Selective separation and recycling of dimethyl ester in method of converting methanol into olefins
SUBSTANCE: claimed invention relates to method of selective isolation of recycling flow, which contains dimethyl ester (DME), from flow, which leaves zone of methanol conversion into olefins (MTO), where said leaving flow contains water, methanol, DME, ethylene, propylene, C4-C6-olefins. Claimed method includes stages: (a) cooling and separation of at least part of leaving flow into liquid flow, which contains methanol and DME, liquid hydrocarbon flow, which contains methanol, DME and C2-C6-olefins, and vaporous hydrocarbon flow, which contains DME, methanol, ethylene and propylene; (b) distillation of DME from at least part of liquid hydrocarbon flow, separated at stage (a) in zone of DME distillation, functioning in conditions of distillation, efficient for formation of vaporous main flow, which contains DME, methanol, ethylene and propylene, and liquid hydrocarbon bottom flow, which contains C4-C6-olefins; (c) mixing of at least part of vaporous hydrocarbon flow, separated at stage (a), with at least part of main vaporous flow, produced at stage (b), with formation of enriched DME vaporous flow of light hydrocarbons; (d) supply of formed enriched with DME vaporous flow of light hydrocarbons into zone of primary absorption of DME, where said vaporous flow is brought in contact with methanol-containing selective with respect to DME solvent in conditions of wet purification, which allows to form (1) liquid bottom solvent flow, containing methanol, DME, water and substantial and undesirable amount of ethylene and propylene, and (2) main vaporous flow of product, enriched with light olefins and depleted of DME; (e) directing of at least part of liquid bottom flow, separated at stage (d), into zone of light olefins distillation, functioning in conditions of distillation, efficient for distillation of at least considerable part of ethylene and propylene, contained in liquid bottom flow, without distilling from there any considerable part of methanol, which results in formation of main flow of distillation section, containing DME, ethylene and propylene, and liquid bottom flow, containing DME, methanol, water and light olefins in amount reduced in comparison with amount of light olefins in liquid bottom solvent flow, supplied to this stage, and (f) recycling of at least part of liquid bottom flow, separated at stage (e) into zone of conversion MTO, thus selectively introducing to it additional oxygenated reactants.
EFFECT: reduction of undesirable increase of C2 and C3-olefins in recycling DME flow.
10 cl, 4 tbl, 2 dwg, 2 ex
The main part of the global petrochemical industry associated with the production of light olefins and their subsequent use in the production of many valuable chemical products by polymerization, oligomerization, alkylation, and other chemical reactions. Light olefins are ethylene, propylene and mixtures thereof. These light olefins are essential building blocks for modern petrochemical and chemical industries. The main source of these materials in today's refining industry is cracking with water vapor of crude oil. For various reasons, including geographic, economic, and political considerations associated with reduction of stocks of raw materials, equipment for a long time seeking non-oil source of mass quantities of raw materials necessary to meet the needs in these light olefins. In other words, the fundamental research staff working in this area, is to find ways for effective and selective use of alternative raw materials for the production of light olefins and thereby reduce the dependence of the petrochemical industry from crude oil. A significant portion of the attention of the prior art was coredata is on the use of hydrocarbons and oxygenates, more specifically, methanol as the main source of necessary alternative raw materials. Oxygenates are particularly attractive for the reason that they can be made from widely available materials, such as coal, natural gas, recyclable plastic, various carbon industrial waste and various products and by-products of the agricultural industry. A method of producing methanol from these types of raw materials is well developed and usually includes the use of one or more of the following operations: (1) production of synthesis gas by any known method, which is commonly used Nickel or cobalt catalyst, with subsequent well-known stage methanol synthesis with application of relatively high pressure on the catalyst copper-based; (2) selective fermentation of various organic agricultural products for the production of oxygenates or (3) various combinations of these operations.
Having developed and well-known technology for the production of oxygenates from alternative non-petroleum origin raw materials, technique focused on the different ways the catalytic conversion of oxygenates, such as methanol, in the target light olefin products. These light olefin products produced from raw materials not of petroleum origin, must be, of course, available in amounts and with such purity that they could be the subsequent processing are interchangeable with the materials that are currently manufactured using petroleum sources. Although in the prior art discussed many oxygenates, the main center of attention of two major pathways for the production of the target light olefins was the technology of conversion of methanol, primarily due to the availability of commercially proven technologies for methanol synthesis. Review of the prior art revealed essentially two main ways, which are discussed in connection with the conversion of methanol into light olefins. The first of these methods, the conversion of methanol to olefins (MTO) based on early German and American work devoted to the catalytic conversion zone containing a catalytic system of the zeolite type. The example of the early German work is US-A-43 87263. In this patent (patent ′263) reported a series of experiments on how the conversion of methanol using a catalyst ZSM-5, where the problem of recycling of dimethyl ether (DME) is the main object of attention of the disclosed technology. Although this patent ′263 reported good outcrops of ethylene and propylene, these outputs are, unfortunately, accompanied the tsya significant education higher aliphatic and aromatic hydrocarbons, which, as suggested by the patent, could be used as a motor fuel and, in particular, as the material type of the gasoline. In order to restrict the amount of heavier material patent owners ′263 proposed to limit the conversion of methanol is introduced at the stage of the conversion process, logistics, to levels below 80%. Work at lower degrees of conversion required critical appraisal tools for extracting and recycling not only unreacted methanol, but also significant quantities produced as an intermediate product of DME. Thus, the invention patent ′263 focused on stage wet scrubbing DME and methanol using water solvent to rational and effective return light petroleum equivalent of unreacted methanol and intermediate participant reactions of DME.
Early work on the procurement system of the zeolite catalyst was continued by the company Mobil Oil Company, which also investigated the use of the system of the zeolite catalyst that is similar to ZSM-5, to obtain light olefins. Early work of the firm is represented by the patent US-A-4587373, which recognises and emphasises the German contribution to this method of procurement to obtain light olefins on zeolite catalyst. Inventor paten is a ′ 373 made two important improvements in this zeolite way ito, the first of which includes the recognition that commercial installation should be operated at a pressure considerably higher than the outside pressure, which was proposed by German researchers in this area, with the aim to give industrial equipment is a reasonable size at commercially reasonable mass costs. In the patent ′373 recognized that, when the purpose of limiting the size of equipment needed for industrial installations in zeolite way MTO, go to higher pressures, there are significant additional loss of DME, which was not considered in the German work. The reason for these additional losses is dissolving significant amounts of DME in the side of the resulting oil from heavy hydrocarbons, which are separated from the liquid hydrocarbon stream withdrawn from the first separator. Another significant contribution of the patent ′373 clearly follows from consideration of the block diagram is presented in figure 2, which clearly shows that part of the methanol feedstock is discharged in the area of absorption DME order to take advantage consisting in the high affinity between methanol and DME, and, thus, reduce the size of the zone of wet cleaning compared to the size of the wet zone of isdi in the case of using pure water, which (zone) was proposed in earlier German work.
First of all, due to the inability called zeolite way MTO to adjust the amount of spam With4+-hydrocarbon products produced by the catalyst of ZSM-5, was soon developed another conversion technology procurement with the use of catalytic material on the basis of neoreality molecular sieves. This is the direction technology procurement, however, best illustrated by the extensive work done in this area by the company UOP, as reported in numerous patents, typical examples of which are US-A-5095163, US-A-5126308 and US-A-5191141. The second option conversion technology procurement was primarily based on the use of a catalytic system comprising silica-alumina-phosphate molecular sieves (SAPO), of which a decisive preference for the species SAPO, known as SAPO-34. It was found that this material, SAPO-34, has a very high selectivity for light olefins, obtained from a methanol feedstock, and therefore a very low selectivity for unwanted respective light paraffins and heavier materials. It is known that these catalyzed SAPO way MTO has at least the following advantages compared with the way the floor is recommended reading light olefins on zeolite catalyst: (1) higher yields of light olefins with the same quantities of converted methanol; (2) the possibility of direct allocation of ethylene and propylene polymer qualifications without having to use the stages of the complex physical separation for separating ethylene and propylene from the corresponding paraffin counterparts; (3) sharply limited output of by-products, such as stabilized gasoline; (4) flexibility in the regulation of weight relationship of ethylene and propylene in the range from 1.5:1 to 0.75:1 with a minimum change of the conversion material and (5) significantly lower coke formation in the conversion zone MTO compared with what occurs in the case of zeolite catalytic system.
Despite promising developments related to the catalyzed SAPO MTO-method for producing light olefins, the problem of simultaneous formation of DME is common to both types of the above catalytic methods procurement and therefore, in the prior art has proposed various measures to retrieve DME from leaving the conversion zone logistics flow and recirculation of DME. In the patent US-A-4382263 for extraction and recycling of the intermediate product DME offers a relatively high pressure in the absorption zone DME using as a solvent of pure water. With regard to the use of the term "high pressure" in relation to the above mentioned patent ′263 are of Kazanian, what examples 1, 2, 3 and 4 were conducted at 2000 kPa, and the fifth example was carried out at higher pressure (4000 kPa). One of the enhancements proposed in US-A-4587373, refers to the use of more efficient solvent for DME in the zone of absorption DME, and provides a recommendation to the part of the methanol feedstock is directed into the reactor conversion MTO, assigned to the zone of absorption DME to more effectively extract the impurity of dimethyl ether from an olefin stream product. In the said patent ′373 proposed to reduce the size of an industrial installation by a significant increase in the preferred pressure in the reactor conversion MTO compared to what was proposed in the prior art, and in particular, we are talking about the operation of the reactor at a pressure of 550 kPa, but noted that the work of the MTO reactor at high pressure can lead to a significant loss of DME with a stream of heavy hydrocarbon products derived from the main separator unit of treatment flowcharts of the process, if no action is taken for distillation, dissolved DME from a stream of heavy hydrocarbon by-products. In particular, the block diagram shown in figure 2 of the patent ′373, serves to expose the distillation of the exhaust from the primary separator 16 heavy hydrocarbon by-product in the stabilization column 26 a is Yu return values dissolved therein intermediate DME while using the DME absorber (22) of the methanol solvent.
In my attempts to introduce technological scheme highlight product, quite similar to that disclosed in figure 2 of the patent ′373, in combination with the use of a catalytic system of the type SAPO in the conversion zone MTO, I was faced with another problem associated with the use of this scheme for extraction and recirculation intermediate DME, which is in admixture resulting from the reaction zone MTO thread. I found that if part of the methanol feedstock is directed into the reactor conversion MTO, is given in the absorber DME, as proposed in the patent ′373, to more effectively extract DME, according to this scheme, there is a significant simultaneous absorption of methanol solvent of light olefins. About the ability of the methanol solvent extraction from the fed to the absorber DME containing light olefins feedstock not only DME, but a significant number With2- and3-olefins, in the patent ′373 were not reported, while this greatly complicates the design of the scheme effective product treatment zone conversion MTO based on SAPO. For example, when the zone of absorption DME operates with methanol solvent under conditions of wet cleaning, including temperature 54°and pressure 2020 kPa, with 99,85% (wt.) methanol solvent, at least, 12.3 wt.% With3-is Levinov and 40.3 wt.% With 3-olefins loaded in DME-scrubber will be absorbed in the output of the scrubber downstream stream enriched DME liquid solvent. When the stream enriched DME solvent recycle to the conversion zone, logistics, creates considerable inner contour of light olefins, which leads to a significant increase in zone size conversion material and thus increases the level of adverse coke formation on contained in this zone, the catalyst due to the fact that the above C2- and3the olefins are chemically reactive and can undergo polymerization and condensation with the formation of coke precursors.
Delivered by the present invention the task is thus to significantly reduce the mentioned undesirable increase in the content of C2- and3-olefins in the recirculation flow DME traveling to the conversion zone MTO in case of using methanol as a solvent in the absorption zone of DME, which is an important feature distinctiveness pattern emerging from the MTO reactor stream.
Disclosure of inventions
The main objective of the present invention is to make the extraction and recirculation contained in the output from the conversion MTO thread DME and/or other oxygenates more selective is compared with the technology of extracting DME, which is known from the prior art, thus creating the possibility of reducing the size of the zone of conversion of procurement by reducing the number of recirculating flow of DME. Another purpose is the provision of a selective method for the recovery and recycling of intermediate DME contained in the output from the conversion MTO thread, which (method) would be significantly lowered the risk of a significant coke formation in used in the conversion zone MTO catalytic system due to internal recirculation of relatively large quantities of highly reactive light olefins.
The present invention solves the problem of pollution of recirculating flow of the methanol solvent light olefins by creating a specially crafted remote area, which is used for concentrating the flow of solvent extracted from the absorption DME, for selective removal therefrom of significant quantities of light olefins without substantial influence on the content in this stream of methanol and, thus, significantly reduce the risks of negative effects on performance zone conversion MTO, when it works in conjunction with the technological scheme of processing effluent from the reactor product.
The author is now established that the problem of light pollution is the olefins, primary oxygenate recycle stream, containing DME and methanol, which is an important distinguishing feature of the technological scheme of processing logistics-product, which is described in US-A-4587373, can be successfully solved by introducing a block diagram of the patent ′373 special distant columns of light olefins. This Stripping column operates at liquid grassroots flow of solvent from the absorber DME and is designed to work in such harsh conditions that a substantial part dissolved in the liquid stream of light olefins was removed from the stream without evaporation of the main part contained in this stream of oxygenates such as dimethyl ether and methanol. The block diagram of the patent ′373 suggests that this enriched liquid oxygenates stream must be subjected to the operation of distillation, oxygenates, which is designed to evaporate essentially all contained oxygenates. This, of course, very different from the decision of a question, a prisoner in my invention, which is based on the assumption that the light olefins can be selectively removed, if the rigidity of the distillation conditions are selected so that this degree was stiff enough to evaporate any significant part of the methanol contained in the liquid stream of the solvent, but would be, which would evaporate essentially of from 90 to 100% ethylene and 40 to 70% impregnated is s, dissolved in the stream of solvent.
The present invention is, therefore, a new method for the selective extraction containing DME recirculating flow of the flow coming from the conversion of ito, which has a side formed water, unreacted methanol, reactive intermediate product of dimethyl ether, ethylene, propylene,4-C6-olefins and a minor amount of other hydrocarbons and oxygenates. The first stage of this method involves cooling and separating at least part of this exit stream water liquid stream containing methanol and dimethyl ether, a hydrocarbon liquid stream containing methanol, DME and C2-C6-olefins, and vaporous hydrocarbon stream containing DME, methanol, ethylene and propylene. In the second stage of this method is obtained from the first stage liquid hydrocarbon stream Argonauts DME in the zone of the distillation DME operating in the distillation conditions effective for the formation of vaporous stream containing DME, methanol, ethylene and propylene, and the liquid downstream of the hydrocarbon stream containing4-C6-olefins. At subsequent stages separated in the first stage vaporous hydrocarbon stream is combined with at least a part of the brain vapor stream produced at the stage from once DME, with the formation of enriched DME vaporous stream of light hydrocarbons, which is then injected into the area of the primary absorption DME, where he comes into countercurrent contact with a selective regarding DME containing methanol solvent under conditions of wet cleaning, effective for education (1) liquid low-flow solvent containing methanol, DME, water, and significant undesirable quantities of ethylene and propylene, and (2) of the vapor stream enriched in light olefins and depleted DME product. At least part of the liquid downstream of the flow of solvent extracted on stage wet scrubbing DME, then send in the distillation zone of the light olefins, functioning in the distillation conditions effective for distillation of at least a significant part of ethylene and propylene contained in this stream of solvent, without Stripping out any significant parts of methanol, resulting in a head-stream of distant sections, enriched with ethylene and propylene and containing trace amounts of dimethyl ether and a liquid bottom stream of solvent containing DME, methanol, water and light olefin in amounts, reduced by compared with the content of light olefins in the liquid downstream flow of solvent extracted at the stage of primary wet cleaning DME. At the last stage, hence, is her least portion of the liquid downstream of the flow of solvent extracted at the stage of distillation of light olefins, recycled to the conversion zone MTO, where, thus, selectively introduce additional reactive oxygenates.
In the second embodiment of the present invention described above, the method further characterized by direction, at least a portion of the flow of distant sections extracted at the stage of distillation of light olefins, in the lower area of the primary absorption DME to retrieve DME, which Argonauts in this zone, the distillation of light olefins.
Another embodiment of the present invention includes the above-described method of the present invention, which is additionally characterized by direction, at least a portion of the flow of distant sections extracted at the stage of distillation of light olefins, in the area of secondary absorption DME, where he comes into countercurrent contact with a selective solvent for DME in terms of wet cleaning, selected so to get depleted DME head stream containing ethylene and propylene, and a liquid bottom stream of solvent containing DME, methanol and water, which recycle on the stage of conversion MTO. The resulting depleted DME head stream is combined with the main stream enriched in light olefins product, the floor is obtained at the stage of primary wet cleaning DME, resulting in a stream of light olefin product, which is derived from the procurement process.
Another embodiment of the present invention includes an additional modification of the methods of selective extraction of DME described in any of the first three embodiments, where the conditions of distillation used at the stage of distillation of light olefins include the severity of conditions sufficient for the production of liquid downstream of the stream of solvent containing less than 1 wt.% of ethylene.
Brief description of drawings
Figure 1 represents the process stream diagram of one of the preferred embodiments of the present invention, which shows a significant mutual relations between work areas associated with the present method for the selective extraction of DME.
Figure 2 represents the process stream diagram relating to the circuit extraction DME prior art.
These drawings are not shown well-known medium-sized specialist items of equipment, such as heaters, refrigerators, heat exchangers, pumps, compressors, vacuum drums, punch, capacitors, collections of head straps, controls, valves and valves, boilers, etc.
Terms and definitions
In the present description uses the following terms and conditions, have their following values: (1) "part" thread means or aliquot part, having the same composition as that of the entire stream, or a portion, receive, separate from the stream easily detachable component (for example, if the stream contains hydrocarbons mixed with water vapor, then condensing the main part of the water vapor stream contains water portion and a hydrocarbon portion); (2) "parent" means the total flow top shoulder, obtained from a particular zone after recycling any parts in the area with the purpose of irrigation or any other purpose; (3) "grassroots" means the total flow surface flow from a particular zone obtained after recycling any parts with the aim of re-heating and/or re-evaporation, and/or after separation of any phase; (4) the line is "blocked"when it has a valve that is installed in a position that blocks the flow on this line; (5) availability of the necessary compressors and/or pumps is implicit in the case, when shown a flow from a zone of relatively low pressure to a zone of higher pressure; (6) availability of the necessary heating and/or cooling means is expected in the case, when shown a flow between zones operating at different temperatures; (7) the ingredient "clubbed" in that case, when it is concentrated in the main stream withdrawn from a particular zone; (8) "vaporous" stream means a stream that contains one Il the more components in a gaseous state, and (9) the term "light olefins" means ethylene, propylene and mixtures thereof.
The implementation of the invention
The starting point for the present invention is a phase conversion MTO, in which as the primary source oxygendemanding reactive agent is methanol. As explained above, there are two different ways of catalytic conversion of methanol to light olefins. The main difference between these two ways based on the type of molecular sieve, which is used as the active catalytic ingredient in the logistic system, and I prefer neoreality way conversion MTO. Details related nezeritis way conversion MTO, described in US-A-5095163, US-A-5126308 and US-A-5191141, the entire contents of which is specifically incorporated into the present application by reference. As indicated in the content of the above patents, the preferred molecular sieve is an aluminosilicate-phosphate (SAPO) system, which was installed, there are many specific crystal structures. As indicated in the above-mentioned patents, the most preferred for the conversion of the MTO structure SAPO was identified as the structure of SAPO-34. Although the method for the selective extraction of the present invention will work equally well with flows originating from areas of conversion MTO, soderzhaniya zeolite, and neoreality catalyst system, preferably, the waste stream was the stream from the conversion MTO working on catalytic system SAPO-34. Molecular sieve SAPO-34 can be used either by themselves or in a mixture with a binder and/or filler and prepared in such form, as extrudates, pellets or spheres. As a binder and/or filler can be used any well-known technique in inorganic oxides of the type of aluminum oxide, silicon oxide, alumophosphate, aluminosilicate and/or one of various well-known medium-sized specialists vysokoglinozemistykh clays. In that case, when compiling the catalytic system SAPO-34 is used a binder and/or filler, SAPO-34 is usually contained in an amount of 5 to 90% by weight of the finished catalyst, and preferably from 5 to 40% of its mass. It should be borne in mind that the active ingredient is a molecular sieve SAPO-34, and the binder and/or filler is an inert material that is used to provide the particles of the catalyst structural integrity. The best results with a catalytic system SAPO-34 are obtained by using this system with a particle size suitable for system reactor fluidized bed, generally the average particle size is between 65 and 85 µm.
Although the area to which nversio procurement can work with any known in the art, the configurations of the reactor, it is preferable to use the system with a fixed layer, and a system with a movable layer that provides an effective contact of the flow of the methanol feedstock with the catalyst particles and facilitates regeneration formed zakoksovanie catalyst. Good results can be obtained with a system with a movable layer and the system fluidized bed. However, the best practical results are obtained using a system with a fluidized bed of catalyst.
The reaction zone MTO fluidized bed operates at conditions that include a temperature of from 300 to 600°With the preferred range is from 450 to 550°C. the Pressure applied at the stage of conversion MTO, usually ranges from 138 to 1000 kPa and preferably from 170 to 345 kPa. The contact time of the reactant with the catalyst is measured, as a rule, the volumetric rate per unit mass of catalyst (WHSV), based on the time consumption of the total mass participates in the reaction of methanol passing through the conversion zone MTO, any other oxygenated chemicals present in raw materials or recirculate, and were there any other hydrocarbon materials, divided by the mass of the molecular sieve SAPO-34 in the conversion zone logistics. WHSV for use in the conversion zone logistics related to the present the invention, can vary in the range from 1 to 100 h-1moreover , the best results are obtained in the range from 5 to 20 h-1. Since the reaction conversion MTO is strongly exothermic, along the reaction zone has a significant temperature rise, typically of the order of from 250 to 500°C. In the system of the reactor with a fluidized bed, the speed of circulation of the catalyst between the reactor and regenerator is installed mainly on the minimum level capable of maintaining the average coking circulating mass preferred SAPO catalyst in the range from 1 to 20 wt.% in the calculation of the active ingredient of the catalyst and more preferably in the range from 5 to 17 wt.%.
On associated with the stage of conversion of the procurement stage of regeneration to remove the necessary amount of coke from the catalyst before it is recycled to the conversion zone typically use one of the accepted oxidative methods. The main factor which determines the circulation rate between the conversion zone and the regeneration zone, is the equilibrium mass of coke on the catalyst, which is desirable to maintain to obtain the desired degree of conversion. Catalytic system based on SAPO-34 works very well when the degree of conversion of 95% or higher, resulting in the coke formation is about 2-5 wt.% equivalents methane is a, introduced on stage conversion MTO. Knowing the rate of coke formation, the average person will be able to set the speed of circulation to the regenerator based on the combustion of coke at a rate that will provide the total average number of coke on the circulating catalyst system used in the conversion zone MTO, in the desired range. Compared with the traditional operation FCC circulation rate in the conversion zone MTO fluidized bed is very low, because there is no need for the regenerated catalyst was enough to heat the reaction zone logistics.
Submitted on stage conversion MTO methanol raw materials can generally be used with a diluent, as described in the prior art mentioned above and included in the present application. In practice, however, it is better not to use a diluent other than autogenous water vapor formed. The use of a diluent is useful in that it allows you to adjust the partial pressure of participating in the reaction of methanol, but it is not beneficial in that it increases the volume of the reaction zone and is additional material that must be separated from the products section of the extract product of the process. When at the stage of procurement is thinner, it is mainly water vapor generated from the water which is inevitable impurity in the flow of the methanol feedstock, and oxygenate recycle streams. Because in many cases it is desirable to load the raw stream of the crude methanol containing up to 20 wt.% water, raw materials flow in this case brings into the system a significant amount of diluent. However, in most cases it is preferable to work with the flow of the methanol feedstock, representing 95-99,9% (by weight) methanol. It must be recognized that a significant number acts as a diluent autogenous water vapor formed in the conversion zone, logistics, because we can assume that the methanol contains about 56 wt.% bound water, and also due to the fact that the kinetics of reactions occurring in the implementation area of logistics, such that the initial formation of DME is extremely fast, resulting in every two moles of methanol reacting with the formation of dimethyl ether, to form one mole of diluent in the form of water vapor.
The waste stream that is output from the conversion MTO, will, therefore, contain a significant amount of the formed side of the water, and unreacted methanol, a significant amount of the intermediate product of dimethyl ether, ethylene, propylene,4-C6-olefins and a minor amount of hydrocarbons and oxygenates. With the preferred catalyst system SAPO-34, when working with her at the degrees to which nversio 97% or higher, usually from about 70 to 78% of incoming to the stage of conversion of the methanol equivalent carbon will be converted to the target With2- and3-olefins, while from 2 to 5% of carbon will turn into coke and approximately 0.5-1% will turn into DME. The number appearing on the stage of the MTO conversion of saturated hydrocarbons, such as methane, ethane and propane, in the case of the use of the catalyst SAPO-34 is typically at very low levels and in the carbon balance is approximately 2 to 5%.
The exhaust stream leaving the MTO reactor typically has a relatively high temperature (350 to 600° (C) and before entering into the zone of separation of the phases must be cooled considerably. Typically, cooling is carried out either by heat exchange with a stream of the methanol feedstock, or by using water cooling flow in the cooling tower, or a combination of both methods. Regardless of the method of heat transfer is preferably substantial cooling and condensation of at least a significant part of the side forming the water contained in the output stream from the conversion, using a cooling tower, working on the cooling medium consisting mainly of water, in conditions of rapid cooling, resulting in the waste stream is partially condensed, separating a substantial portion p is formed in the side zone conversion MTO water. The cooling tower is typically operates at a pressure of from 40 to 95% pressure maintained in the conversion zone, logistics, and the main flow of this cooling tower along with the hydrocarbon and oxygenate products of the synthesis reaction still contains substantial amounts of water vapor. Scheme is preferred for this application two-stage cooling towers described in the patent US-B-6403854, the entire contents of which is included, therefore, in the present application by reference. After selection named head of product from the cooling tower is preferably pass it through a series of vacuum drums and compressor for raising the pressure in the range from 2000 to 2600 kPa.
Let us turn now to the accompanying figure 1 is a diagram of a product of the present invention. Figure 1 is a schematic plan of interdependence and interrelation between different areas for one of the preferred embodiments of the present invention. Zone 1 represents the conversion zone MTO, which serves methanol feedstock entering the system through line 10. Zone 1 operates in accordance with the description above, producing the output stream that exits from zone 1 through line 13 and is fed into the lower region of the cooling zone 2, where he prototechno contact with circulating chilled water flow, resulting in condensate significant portion side formed in the reaction zone MTO water. In zone 2 shows the drainage water cooling medium line 15 and recycling it to the top area rapid cooling 2 after passing through the corresponding cooling device (not shown). Of the circulating water flow in the zone of rapid cooling is discharged through line 16 and is directed to the zone selection oxygenate 3, which consists in Stripping, essentially the entire amount of oxygenates, which are dissolved in the circulating water leaching environment, and in the extraction and circulation of these oxygenates in the conversion zone MTO (1) on lines 17 and 10. The flow of water, which contains almost no impurities, is removed from zone 3 through line 18 and represents the major portion of the formed side of the water. The resulting cooled and then quickly cooled head steam stream is withdrawn by line 14 of the rapid cooling zone 2, is compressed using a not shown device until the pressure in the previously specified limits, and serves the area of the primary separation of the product 4, which operates at a temperature of from 10 to 100°C, preferably from 20 to 60°providing the division into three phases. Received in the primary separator vapor stream is removed from the separator through line 22 and is fed into the lower region of the zone of initial absorption DME 6. Formed in zone 4 liquid hydrocarbon phase contains a significant share of the VA DME, light olefins and dissolved therein unreacted methanol and sent via line 25 in the distant zone 5, where this phase is in contact with the rising generated in the evaporator (not shown) of the steam flow in the distillation conditions effective for removal from the hydrocarbon stream DME and light olefins and create exhaust line 26 vaporous head stream containing DME, ethylene and propylene together with minor amounts of light-saturated compounds, which are dissolved in the stream of relatively heavy hydrocarbons. Liquid hydrocarbon stream is withdrawn from the bottom of distillation zone DME 5 and supplied from this zone through line 27 is a flow formed in the side reactions procurement of heavy hydrocarbons, which mainly consists of a4-With5- and6-olefins in a mixture with a minor amount4+-saturated hydrocarbons. In the preferred procurement with a catalytic system SAPO-34 exhaust line 27 liquid stream of heavy hydrocarbon contains from about 8 to 18% of the methanol equivalent carbon introduced into the conversion zone logistics 1.
At the intersection of line 26 from line 22, at least a portion of the vaporous hydrocarbon stream from the separation zone 4 is combined with at least a part of the brain vapor stream produced in the zone of othank the DME 5, with the formation of enriched DME vaporous stream of light hydrocarbons, which is supplied via line 22 into the bottom area of the primary absorption DME (6). Area of the primary absorption DME (6) represents the normal contact area of liquid-gas, filled with a suitable nozzle, is well known to specialists, with the aim of strengthening cooperation between the pair of fluid in the process of contacting the upward steam flow with a downward flow of liquid. Appropriate means for a contact are various well-known specialists profiled supplementary materials, as well as plates for vapor-liquid contact, such as the well-known multilevel drain plates supplied by the company UOP. Served in the area of washing DME (6) the solvent is in accordance with the present invention a part of the methanol feedstock that enters the process flow through line 10 and passes through line 11 to the upper section of the absorption zone 6, where it comes into countercurrent contact with the rising enriched DME vapor stream of light hydrocarbons, which is fed to the wet scrubbing zone 6 through line 22. Supplementary material for wet scrubbing zone 6 are usually ring processTRwhich are inert with respect to the input in the wet scrubbing zone 6 different active ingredients and are highly effective in massop is passing, promote interaction between ascending vapor flow and a downward flow of the methanol solvent. The wet scrubbing zone 6 operates under conditions effective to create a liquid grassroots stream of solvent containing methanol, DME, water, and a significant and undesirable quantities of ethylene and propylene, and vaporous head stream enriched in light olefins and depleted DME product. Preferred conditions include wet scrubbing pressure in the range from 1896 to 2241 kPa and a temperature of from 20 to 66°C, and the pressure measured at the top of the column, when the vapor head stream is discharged through line 20, and the temperature measured at the bottom of the column, when enriched DME solvent is discharged through line 21. Used in the wet scrubbing zone 6 the ratio of vapor to liquid is determined not only by the concentration of methanol supplied up zone 6 through line 11, but also the concentration of DME in the incoming vapor stream which is introduced into the bottom of the same zone through line 22. As mentioned above, used the flow of the methanol feedstock to the conversion zone MTO usually has a concentrated form containing up to 99 wt.% methanol or higher. However, in some cases, when economic considerations dictate the use as a raw stream in the conversion zone logistics flow of the crude methanol,the methanol content can be reduced to 80 wt.% of methanol. The methanol solvent is supplied to the wet scrubbing zone 6 on lines 10 and 11 may in this case be the concentration of methanol from 80 to 99.9 wt.% and, when the conversion zone logistics serves concentrated methanol feedstock preferably contains from 95 to 99.9 wt.% of methanol. The concentration of dimethyl ether in the vapor stream entering zone 6 through line 22, may vary from 0.5 to 2.5% by weight of the total vapor flow. On the basis of the number of these variables it is advisable to carry out the wet scrubbing zone 6 when the mass ratio of solvent to a couple of from 1:1 to 3:1, with best results being obtained when the mass ratio of solvent to a couple of from 1.2:1 to 2.5:1. The exact values of the mass ratios of solvent to steam in zone 6 choose within the limits established with the purpose of the preferred removal from 85 to 99.99 wt.% DME, which enters the zone through line 22. The best practical results for the methanol solvent containing at 99.5 wt.% or more of methanol, is achieved by using the ratio of the solvent to a couple within the limits established for the purpose of removal from 95 to 99.9 wt.% DME, which enters the zone through line 22.
At least part of the depleted DME and enriched in light olefins vaporous head stream from the wet scrubbing zone 6 is preferably passed then through line 20 to the lower area and zone recovery of methanol 9 to remove from this stream of residual methanol vapors. As a result of the wet scrubbing zone 6 necessarily formed vaporous stream, which in the conditions that prevail at the top of zone 6, saturated with methanol, this thread will contain from 1.5 to 5.5 wt.% of methanol. To remove this small amount of methanol, dissolved in withdrawn from zone 6 vaporous head thread, this thread serves on line 20 in the lower region of the zone of recovery of methanol 9, in which from this thread laundered methanol part received in the area of extraction of oxygenates (3) stream side of the formed water, which is sent to the zone 9 through lines 18 and 19. Area extraction methanol 9 completed appropriate means to ensure contact vapor-liquid, such as those mentioned above in connection with the work zone 6, which facilitates washing of methanol of these vaporous stream. The resulting depleted methanol vapor stream of light olefins is withdrawn from zone 9 through line 32, is a stream of light olefin product of the present invention. In one of alternative embodiments that are not shown on the attached drawing, a stream of light olefin product can directly be selected from line 20, if a minor amount of methanol losses valid and the methanol will not affect subsequent processing.
Return ASAS to the downstream flow of liquid solvent, the output from the wet scrubbing zone 6 through line 21, we note that this stream contains methanol, DME, water, and significant undesirable quantities of ethylene and propylene. As presented in figure 2 of the patent US-A-4587373 the block diagram of the prior art shown that the flow of liquid product from the DME absorber 22 is fed to a separator, where the water phase is separated from the liquid hydrocarbon phase, which is then returned to the distillation zone DME 26 running on liquid hydrocarbon stream to be extracted from the primary separator. Obviously, in the prior art has not recognized that, despite the separation of the phases, a stream enriched in methanol solvent still contains substantial amounts of ethylene and propylene, which in the case of recycling in the conversion zone logistics through the device for distillation, oxygenates 18 in the patent ′373 can cause significant internal recirculation of these very reactive materials that will lead to an increase in zone size conversion MTO, as well as to decrease the stability of the catalytic system due to unwanted polymerization and condensation of these very reactive light olefin materials. Indeed, for a zone of wet cleaning DME, working as described in relation to zone 6 of the present invention, enriched liquid DME RA is the solvent, exhaust from a bottom zone through line 21, even after separation of the hydrocarbon phase will contain dissolved therein from 10 to 15 wt.% ethylene, which arrives in zone 6 through line 22, and from 35 to 50 wt.% propylene served in this column. The existence and magnitude of the mentioned internal re-circulating stream of light olefins, obviously, were not understood and have not been evaluated in the flowsheet shown in figure 2 in the patent ′373.
According to the present invention, at least part of the liquid downstream of the flow of solvent drawn from the wet scrubbing zone 6, is passed by line 21 to the zone of distillation olefins 7, which operates at this level of stringency conditions, which is sufficient for distillation of a significant part of ethylene and propylene contained in the liquid downstream flow of water solvent, without distillation of the flow of any substantial parts of methanol, resulting in a gain head flow organoclay sections containing dimethyl ether, ethylene and propylene, and water surface stream containing DME, methanol, water and light olefins in quantities reduced in comparison with the olefins in the liquid downstream flow of the solvent supplied to the zone 7 through line 21. Preferably named stage distillation olefins in the level of stringency conditions sufficient to repel C is aceteline part of light olefins, while retaining essentially all (i.e. at least 90% or more) of the methanol contained in the input liquid stream of solvent, forming part of the liquid downstream of the flow of solvent extracted from zone 7. In particular, the level of stringency conditions are preferably set so that the output from this zone through line 21 depleted light olefins liquid grassroots flow to this area leaves from 95 to 99 wt.% methanol, coming in the distant zone 7 through line 21. Typically, the level of stringency conditions are defined in terms of temperature, pressure and rate of distillation, set so that formed downstream water flow from zone 7, containing less than 1 wt.% ethylene, and the best results are obtained in the case when the hardness level is set to the lower stream contained less than 0.25 wt.% of ethylene. It should be noted that in the distillation zone of the light olefins 7 can be used evaporator (not shown) to generate the ascending vapor flow in the quantity necessary for the distillation of light olefins, or, as shown in the drawing, to ensure necessary for distillation environment can be used optional not containing light olefins gaseous stream is introduced into the bottom of the distant zone 7 through line 33. Of course, the scope of the invention allows operation from the Onna area 7 with a combination of built environment, generated in the evaporator (not shown), with depleted in olefins Stripping gas supplied to zone 7 through line 33. Enriched with oxygenates and depleted in olefins liquid stream removed from the bottom of the distillation zone of the light olefins 7, line 28, then recycle through lines 30 and 10 back into the conversion zone MTO to provide an additional reagents for the conversion in it.
Containing light olefins vaporous stream withdrawn from distant zone 7 through line 29 contains minor quantities of dimethyl ether, which boils together with contained therein propylene material, as a consequence, the necessary subsequent processing stream in order to remove DME. According to one embodiments of the present invention, at least part of this vaporous head of the stream that is output from the distant zone 7, is supplied via lines 29, 35 and 22 in the lower region of the zone of initial absorption of dimethyl ether in order to remove this residual flow DME. In this embodiment, the area of the secondary absorption DME (8) is not used, and in line 29, after crossing with a line 35 to a suitable shut-off valve to cut off any flow in zone 8. The impact of this recycling at least part of the vapor downstream of the stream withdrawn from the distillation zone of the light olefins 7 in the area of the primary absorption DME (6) is, of course, to increase the steam supply in tomorrow purification 6, the result is a proportional increase in the amount of the solvent supplied to the zone 6 through line 11. The amount of increase in the supply of steam to the zone 6 is approximately 15 to 40 wt.% from steam in zone 6 if there is no such recirculation line DME.
In the second and preferred embodiment of the present invention, the line 35 is locked by a valve (not shown) and at least a substantial portion of the vapor downstream of the stream withdrawn from the distillation zone of the light olefins 7, is supplied via line 29 into the lower area of the secondary absorption DME (8), where this vaporous stream comes into close contact with the descending liquid stream containing the solvent for DME. Considering the fact that the mass flow rate and the concentration of dimethyl ether in the vapor stream entering zone 8 through line 29, less than the corresponding values for vapor flow, which enters the area of the primary wet cleaning 6 through line 22, and that opportunities for resource savings are much higher, the best option is to use for absorption DME of the vapor downstream of the flow area of the secondary wet cleaning DME (8) when the mass ratio of steam applied to the area of secondary absorption DME to the couple served in the area of primary absorption DME average of from 0.15:1 to 0.4:1. Used in the area of secondary wet cleaning DME (8) RA the solvent may be or any suitable selective for DME solvent, or the second part of the methanol stream of incoming raw materials to the stage of conversion MTO, which in this case would be to zone 8 through lines 10 and 12, and the line 34 in this case will be locked valve (not shown)located on line 34 prior to its connection with line 12. In this mode of operation as the initial absorption zone 6 and zone secondary absorption 8 will work on the solvent of the same composition, since they are both parts of the flow of the methanol feedstock supplied to the conversion zone logistics. The means of implementation of a contact used in zone 8 to ensure close contact between rising vapor flow and a downward flow of the solvent, preferably the same as those applied in zone 6, and used in zone 8 conditions wet cleaning include the mass ratio of the solvent/vapor from 1:1 to 3:1, the same as in the case of zone 6, but the size of the zone 8 will be much smaller than zone 6, and opportunities for resource conservation using the appropriate heat-exchange operations is in this embodiment a lot more.
Since most of the work for removing DME from vaporous stream withdrawn from zone conversion ito (1), is in zone 6, the final purification of the resulting zone of wet cleaning 7 light olefins, carried out in the area again the wet cleaning 8, provides an additional opportunity to use in zone 8 other selective regarding DME solvent. Since the work associated with wet cleaning DME in zone 8, much less the work that must be done in the area of primary absorption 6, it is possible to use for operation in zone 8 as selective regarding DME solvent portion of the stream formed side of the water, which is diverted from the area extracting oxygenates 3. In this embodiment used in zone 8 the solvent passes from zone 3 through means (not shown) in the upper area of the wet scrubbing zone 8, while line 12 is blocked by a valve (not shown), which closes the passage of the methanol feed to zone 8 via line 10 and 12. In this case, when the solvent in the zone of secondary wet cleaning DME (8) is formed of side water supported in this zone, the conditions will be similar to the conditions maintained in zone 6, except that there the mass ratio of solvent/steam will be increased from 1.5 to 5 times in order to take into account the fact that DME has compared to methanol lower affinity to water.
In the case when in the zone of secondary wet cleaning is the preferred methanol solvent, this area will work in conditions that matched the s so, to produce depleted DME vapor top stream containing methanol, ethylene and propylene, and a liquid bottom stream containing DME, methanol and water, which is usually recycle lines 30 and 10 to the conversion zone MTO (1) for the purpose of submission there of additional quantities of the reactants. As shown on the attached figure 1, it is preferable to skip depleted DME vapor parent hydrocarbon stream withdrawn from zone 8 through line 31 through the zone of recovery of methanol 9 with the purpose of capture and recycling of minor amounts of methanol, which may be contained in this thread. If loss of methanol can be valid for zone conversion MTO from an economic point of view and if the presence of this minor amount of methanol is not dangerous for any of the units further processing of light olefins, at least a portion passing through line 31 downstream of the flow can be combined (using means which are not shown) with the main stream enriched in light olefins and depleted DME product extracted from the top of zone 6 and supplied directly to the installation further processing. The best option is the implementation of the present invention is, however, in applying both enriched in light olefins streams in the area of recovery of methanol 9 the purpose of washing out the residual methanol, as already mentioned above. In this latter case, enriched in light olefins vaporous stream withdrawn from the top zone of the scrubbing methanol 9, line 22, is a stream With2- and3-olefinic product of the present invention.
To further facilitate understanding of the present invention, the following examples in comparison with the control sample. However, these examples are not to limit the invention, and to illustrate. These examples demonstrate the difference between the results using the scheme of the present invention and results obtained in accordance with the scheme highlight product disclosed in the prior art. Scheme highlight product of the present invention is shown in figure 1, and the allocation of the product of the prior art in figure 2. Comparison of the two drawings shows that, to the extent possible, common to the two block diagrams of receipt of the product elements have the same numbers, which facilitates their direct comparison. In both examples, the conversion zone MTO mode fluidized bed with catalyst SAPO-34. The catalyst SAPO-34 prepared according to the recommendations of the US-A-5191141 and apply a particle size suitable for fluidization (i.e. average particle diameter equal to 70-80 μm). the leaves are used in both examples of the catalyst particles is the basis of 40 wt.% molecular sieves SAPO-34, related to 60 wt.% inert fill/binders.
Supplied to the conversion zone 1 through line 10 commodity flow in both cases consists of a mixture of methanol and water containing of 99.85 wt.% of methanol. Neither is any other example does not use thinner, since significant quantities acts as a diluent of water vapor formed in the area due to the very fast kinetics of formation of the intermediate DME.
Used in both cases in zone 1 operating conditions are as follows: (1) the temperature of the raw input flow 100°and the temperature of the exit stream at the output of 475°With; (2) pressure 239 kPa; (3) the volumetric rate per unit mass of catalyst WHSV=2.4 h-1calculated on the total weight of the catalyst, and the catalyst is recycled after separation of the normal way of product, mainly using internal or external recirculation means; (4) the output rate of the catalyst in the regeneration of the circulating mass of catalyst in zone 1 in amounts sufficient to maintain the average amount of coke in the catalyst in the circulating catalyst inventory in the range of 2 to 5 wt.% The inferred catalyst is subjected to oxidative regeneration in the existing scheme of a conventional regenerator (not shown in any one of the accompanying drawings) to reduce to the KSA to 1 wt.% or less, after which the regenerated catalyst is recycled to the conversion zone logistics to maintain a given content of coke in the circulating catalyst inventory.
Work area 1 in both the examples provided in these conditions with a given catalytic system and a methanol feedstock allows to achieve a conversion of 99.5 wt.% consumption of methanol and food composition shown in table 1, based on the balance carbon.
Because methanol contains about 56 wt.% bound water, water is a very important by-product in the reaction MTO occurring in zone 1, and in both examples, in order to prepare a portion of the exhaust flow direction in the allocation of product from the waste stream it is necessary to condense large quantities of water and to separate it from the hydrocarbon products of the reaction zone logistics.
|The yields of products from the conversion MTO|
|Component||Selectivity (wt.% methanol equivalent)|
|Other (N2, CO, CO2diene)||1,29|
The exhaust stream leaving the conversion zone MTO (1) in line 13 may be subjected to the usual operations of cooling, such as heat transfer raw material/waste stream (not shown), and filed with the quick cooling zone 2, where the flow undergoes additional cooling for the purpose of condensation contained significant quantities of produced water side. The quick cooling zone 2 operates as described above, with a circulating cooling medium, mainly water, which prototechno contact with hot, containing large amounts of water vapor, the exhaust flow from zone 1 thus, in order to condense the major portion of the water formed in the side on the stage of conversion, logistics, and reduce the temperature of the exhaust stream to such an extent that the hydrocarbon part came out of zone 2 through line 14 at a temperature of 40°and a pressure of 200 kPa. In both examples of the circulating line 15 of the aquatic environment is given to the via line 15 and is fed to the extraction of oxygenates 3. Zone 3 operates in normal conditions of distillation, oxygenates, involving distillation, essentially the entire amount of oxygenates, which are then recycled to the conversion zone MTO (1) on lines 17 and 10. These oxygendemand materials are accumulated in the above-mentioned circulating cooling medium due to their high solubility in it. Water flow output line 18 from the lower region of the zone of extraction of oxygenates 3, is essentially pure water with very small amounts of dissolved impurities.
Containing hydrocarbons and oxygenates vaporous head product from the top of the rapid cooling zone 2 is fed by line 14 in the area of primary separation of the product 4. The path of this vaporous stream from zone 2 to zone 4, it passes through a series of vacuum drums, compressors and coolers (not shown in the accompanying drawing) to increase its pressure to 2069 kPa and, in the end, the thread enters the area of the primary separation of the product 4 at a temperature of 38°and is maintained in these conditions in zone 4 to effect the separation of the three phases, then enriched with the hydrocarbon vapor phase is removed from zone 4 through line 22, heavy liquid hydrocarbon phase is removed from the zone through line 25 and the aqueous phase is diverted from there through the line 23. Figure 1 example 1 aqueous phase from zone 4 removed from this AOR is s on line 23 and fed through lines 24 and 15 in the area of extraction of oxygenates 3. In the figure 2 example 2 the block diagram of the water flow from the primary separator product is also fed to zone 3 except that in this case it is taken along the lines 21, 31 and 16 to the extraction of oxygenates 3.
In both examples 1 and 2, a liquid hydrocarbon phase, which is removed from the zone of primary separation of the products 4, line 25, is fed to the distillation DME 5, which operates under pressure in the upper part of the remote device and discharged to the parent product, at 172 kPa below the pressure maintained in zone 4. In the zone of the distillation DME 5 has an evaporator (not shown in any of the drawings)to generate a rising pair, which in both cases is distilled dimethyl ether and olefins dissolved in the incoming hydrocarbon stream head stream, which is removed from this zone through line 26 and enters the exhaust system with line 22, in which this stream is combined with the main product from the zone 4. The resulting mixture flows then through line 22 into the zone of initial absorption DME (6). Enriched With4+-material liquid hydrocarbon stream is given in both examples 1 and 2 from the bottom of zone 5 through line 27. This grassroots stream contains4- and5-olefinic products zone conversion MTO together with various other heavier hydrocarbon by-products. This thread is serious is the logo of the hydrocarbon product is removed through line 27 and enters additional device for processing heavy hydrocarbons, located after the procurement process.
On the block diagram of the present invention used in example 1 as well as in the block diagram of the prior art used in example 2, area 5 provides an additional tool to retrieve DME, as well as to extract light olefins. Head vaporous stream that is separated in the primary separator product 4 concatenated in both cases with the main vapor stream from a distant zone 5 at the intersection of the lines 22 and 26, and the resulting combined vapor stream flows through line 22 into the bottom area of the primary absorption DME (6). It should be borne in mind that due to the difference in pressure between the vapor flow in line 22 and line 26 to provide such a head stream of DME from zone 5, as described above, in the line 26 may be required by the compressor.
As in the allocation of product of the present invention (shown in Fig.1), and in the allocation of the product of the prior art (shown in figure 2) for the removal of dimethyl ether from light hydrocarbon reaction products of conversion MTO in the wet scrubbing zone 6 is enriched in methanol solvent. In both cases, a methanol solvent receive as part of the flow of the methanol feedstock that enters the process through line 10. The part that is used in the wet scrubbing zone 6, which is found in line 11 and enters the upper region of the wet scrubbing zone 6, in which it is passed in countercurrent to the ascending United-containing hydrocarbon vapor stream, which enters the lower portion of zone 6 through line 22. The amount of the methanol solvent, which is discharged through lines 10 and 11 for use in the area of the wet purification of dimethyl ether and other oxygenates from light hydrocarbons vapor introduced into the lower portion of zone 6 through line 22, is from 50 to 100 wt.% from the total mass of the raw material introduced into the conversion process of procurement through the line 10. In both cases, the zone 6 operates in conditions of wet cleaning DME, including temperature 54,4°C, pressure 2020 kPa and the mass ratio of the solvent/vapor equal to 1.32:1, resulting in a depleted DME and enriched vaporous hydrocarbons head flow, which in both cases is out of zone 6 through line 20, and enriched DME liquid flow of the methanol solvent, which comes from the zone 6 through line 21. The temperature and pressure in zone 6, as mentioned above, measured at the point of diversion downstream gaseous stream.
After describing the common elements used in both examples, block diagrams to illustrate the difference between the flowcharts 1 - one of the embodiments of the present invention used in example 1 scheme of the prior art, figure 2 used in example 2, then details two examples.
Example 1 (present invention)
Used in this example, the block diagram of the extraction of the product shown in figure 1 except that in this embodiment of the present invention, the area of the secondary absorption DME (8) is not used. Therefore, to disable the zone of the secondary absorption DME (8) line 12, 31, 30 to the intersection with the line 28 and line 29 to its connection with the line 35 is overlapped with valves (not shown).
In this embodiment, the area of washing DME (6) operates as described above, when discussing the common elements for both block diagrams except for the increased load, which is imposed on this area in the recirculation downstream of the flow generated in the distillation zone of the light olefins 7 and supplied to the zone 6 through lines 29, 35 and 22. It should be borne in mind that between zone 7 and zone 6 may be a differential pressure, and in this case, to increase the pressure of the named head of the stream to a level which is higher than the pressure in the lower part of zone 6, there is a need for compressor means (not shown) on line 35. Area of the primary absorption DME (6) operates as described above, except that the load pair in this area increased by 25%, and to maintain the mass ratio solvent/vapor equal to 1.32:1, requires a corresponding increase in the number of the methanol solvent, which through the line 11 is removed from the line one 6, thus, operates as described above, producing a vapor top stream that is depleted of DME and enriched With2- and3-olefins. Since this enriched olefin vapor stream also contains some amount of methanol is determined by the equilibrium vapor-liquid supported in the upper part of zone 6, in this embodiment of the present invention preferably this upper stream is fed by line 20 in the area of recovery of methanol 9, where the vapor top stream from zone 6 would come into countercurrent contact with a stream of an aqueous solvent under conditions conducive to wash this vaporous stream almost all the methanol. Used in the area of extraction of the methanol aqueous solvent is served in this area along the lines 18 and 19 as part of the stream formed side of the water, which is created in the zone 3. Area 9 contains a special contact means of facilitating interaction introduced through line 19 water solvent with the ascending vapor stream, which enters the bottom of this zone on the lines 20 and 31. Area 9 is at a temperature of 25°C, pressure 1813 kPa and a mass ratio of the solvent to the total number of the input pair is equal to 3:1. Thus, zone 9 operates so as to remove essentially all of the methanol from the stream of light Ola is new product of the present invention, which is formed in the form of the head of the product and is removed from this zone 9 through line 32, forming the main flow of light olefin product in the scheme of obtaining the product of the present invention. The stream containing methanol water solvent being withdrawn from the bottom of zone 9, recycle to zone 3 on the lines 24 and 16 with a view to eventual return contained in the solvent of methanol to zone 1 through line 17.
Returning to the work area 6, note that the flow of the methanol solvent with a high content of DME withdrawn from zone 6 through line 21, is served according to the present invention in the distillation zone of the light olefins 7 and is included in this zone mid-point or below it. The distillation zone of the light olefins 7 operates in accordance with the present invention with such stringency conditions, which is sufficient for distillation significant part C2- and3-olefins contained in the stream enriched DME solvent, which is served in this area in line 21, but not sufficient to remove a substantial portion of the methanol contained in this stream of solvent. In other words, installed in zone 7 the degree of stiffness is significantly less than the hardness installed in the area of extraction of oxygenates 3, where there is a need to drive off essentially all of the oxygenates in the head vaporous stream. As mentioned above, zone 7 who can work with to facilitate the Stripping gas environment which is depleted in olefins and enriched with methanol and which can enter the zone 7 through line 33. Alternatively, zone 7 can work with the evaporator (not shown) and may be autologous to generate ascending pairs by evaporating part of the depleted light olefins methanol solvent being withdrawn from the bottom of this zone through line 28. For example, line 33 can be blocked and can be applied to the system evaporator to generate the total number of ascending vapors using a suitable recuperating heat tool (not shown)located on the line 29 to minimize the funds associated with the operation of evaporation using an evaporator. In this example, zone 7 operates in conditions that are sufficient for distillation, essentially, the total amount of ethylene contained in the feed to this zone enriched DME solvent. These conditions include the pressure 1827 kPa and temperature 76,7°With that measured at the point of diversion head vaporous stream from zone 7 through line 29. When working in these conditions in zone 7 is removed 100% of the ethylene contained in the enriched DME methanol solvent supplied to this zone on line 21, and 51.2% of propylene dissolved in the enriched DME methanol solvent. The resulting enriched in light olefins vaporous head stream that is diverted from areas of the 7 line 27, unfortunately, contaminated with a minor amount of DME, due to the high affinity between DME and propylene. According to this method of implementing the present invention, which is illustrated in the above embodiment, it is necessary to return a named stream of light olefins in the area of primary absorption DME (6) for cleaning of this thread impurity DME. As mentioned above, the head stream from the distillation zone 7 is supplied via lines 29, 35 and 22 in zone 6. The bottom stream from zone 7 is discharged through line 28, and a stream depleted in light olefins and enriched DME methanol solvent which is returned to the conversion zone MTO (1) along the lines 28,30 and 10.
The calculated efficiency of the separation and extraction related to this example embodiment of the present invention, are presented in table 2 in tabular form, where in the first column are the main products, in the second column is the percentage of products in the recirculating liquid stream and the third column gives the percentage of product in the stream of light olefin product is withdrawn by means of this method of obtaining product on line 32. Based on the data of table 2 it can be shown that the present invention brings the product yield for the technological scheme of production of the product up to 100%, which sharply ex which differs from the output to the prior art, equal 87,71%, which is shown below in table 3.
|Efficiency* separation and extraction of the technological scheme of production of the product of the present invention|
|The reaction product procurement||Extraction (%) in the recirculating stream||Extraction (%) in the flow of product|
|* Measured in wt.% regarding the reaction products procurement in a single pass.|
From the fourth row in table 2 one can see that the level of extraction of propylene increased to 80%, which differs sharply from the level of extraction 59,72% technological scheme of the prior art, an example of which is shown in comparative example 2. It should be noted that this increase in the level of extraction of the target light olefin was not accompanied by any loss in the extraction of DME, which is clearly demonstrated by the comparison of R which results in the efficient recovery of DME in tables 2 and 3.
Example 2 (comparative)
Turning now to the details of the work zone wet cleaning DME (6), figure 2, according to the description of US-A-4587373, you can see that enriched DME methanol solvent which is drained from the bottom of zone 6, is supplied via line 21 and line 16 in the area of extraction of oxygenates 3 the purpose of distillation, as extracted DME and methanol solvent from a number contained in the water flow, and recirculation is obtained as an intermediate product of dimethyl ether and unreacted methanol in zone 1 through line 17. You should pay attention to the fact that enriched DME methanol solvent which is withdrawn from zone 6 through line 21, may be the traditional way directed in patristical (not shown) for separating a quantity of relatively high-boiling hydrocarbons (i.e.4+-material), which is condensed in zone 6 through supported in this zone conditions. Stream depleted in DME containing light olefins vaporous product is given after that of the upper region of the wet scrubbing zone 6 through line 20 and fed to further processing, which is not part of the procurement of the patent ′373.
The purpose of figure 2 is to show the block diagram, shown in figure 2 US-A-4587373. In figure 2 of the patent ′373 area 12 corresponds to zone 1, the proposed figure 2 and represents the conversion zone logistics. The quick cooling zone 2 is functionally represented by a cooling zone 14 of the patent ′373. Area extracting oxygenates 3 attached figure 2 corresponds to a section of the distillation, oxygenates 18 patent ′373. Primary product separator 4 corresponds to the separator product 16 patent ′373. The distillation zone DME (5) are presented in figure 2 of the patent ′373 stabilization tower 26, and the wet scrubbing zone 4 presents the absorber DME (22).
Applying the above operating conditions, are presented in table 1 degree of conversion of DME and well-known affinity for DME, the solidity of the solvent with high methanol content, the efficiency of separation and recovery related to technological scheme of production of the product of the prior art, were calculated using the simulation scheme of the traditional chemical process (which was also used for the calculations presented in table 2). The results of these calculations are presented in table 3 in the form of outputs for different product key zone conversion MTO.
|Efficiency* separation and extraction of the technological scheme highlight product of the prior art|
|The reaction product procurement||Of the treatment (in %) in the recirculating stream||Extraction (%) in the flow of product|
|* Measured in wt.% regarding the reaction products MTO per one pass.|
In table 3 the efficiency measured in wt.% specified in the first column of the reaction product procurement extracted using the separation system for the product in one pass. For example, in the case of ethylene, the results indicate that 87,71 wt.% ethylene formed in the conversion zone ito (1), remove the head stream 20 from the zone of wet cleaning DME 6, which is a stream of light hydrocarbon product patent ′373. The remainder of ethylene, in contrast, is dissolved in the enriched methanol solvent, the output from the bottom of the wet scrubbing zone 6 through line 21 and recycled to the conversion zone MTO (1) through line 21, 16, zone 3, and lines 17 and 10. In respect of propylene results are even more impressive in that 59,72 wt.% propylene formed in zone 1, enters the C process on line 20 as part of the flow of light olefin product system product receipt, illustrated in figure 2. However, it is surprising that a significant portion of the propylene is returned to the conversion zone MTO (1) due to its high solubility in methanol solvent used in the wet scrubbing zone MTO (6). Recycled propylene passes through lines 21, 16 in zone 3, where he Argonauts in the head stream leaving zone 3 through line 17, to which he finally returned to the conversion zone MTO (1) in line 10.
The main lesson that should be learned from the study are presented in table 2 the results of calculations, is that the use of a methanol solvent in the wet scrubbing zone DME (6) has as the undesirable consequences of the seizure of significant quantities of C2- and3-olefins to internal recycle stream with which they are returned to the conversion zone MTO (1) and, in the end, is formed in the processing circuit internal circuit of light olefins, which increases the concentration of these materials in the stream 13 to such quantities, leaving the system through line 20, cancel quantities of light olefins produced in the reaction zone MTO (1). This recirculation path of light olefins, which thus takes place in the technological scheme of the patent ′373, an unwanted consequence of the use of methanol as races is vorites in the area of wet cleaning with the purpose of take advantage of well-known affinity of methanol to DME.
When comparing the results given in table 2, with the results shown in table 3, it becomes obvious that the main advantage that makes the present invention is, therefore, significant reduction in the rate of recirculation of light olefins, which is required for 100%extraction of target light olefin products produced in the conversion zone MTO (1). The degree of improvement obtained in the embodiment of the present invention shown in example 1, in comparison with the flow chart illustrated in example 2, identified in table 4, which shows the ratio of recirculation required for 100%extract the two target light olefin products from the reaction ito in the form of a recirculation ratio required for each of these products in order to withdraw from the system 100% of the products zone 1 through line 32 in the case of figure 1 and 20 in the case of figure 2.
|The recirculation ratio*required for 100%extract C2- and3-olefinic products from reaction stage MTO**|
|Product||Technological scheme of the prior art||Technological scheme nastojasih the inventions||Improvement|
|* Recycling + raw material/raw materials.|
|** Based on the amount of product that should be recycled to ensure 100%extraction of this product per one pass.|
As follows from the first row of table 4, the present invention improves the ratio of recycle ethylene 12.3%. Even more striking results were obtained in relation to propylene reaction product conversion MTO. As follows from row 2 in table 4, the present invention provides 26,2%improvement in coefficient of recirculation. The present invention clearly and convincingly demonstrates significantly lower rate of recirculation needed to extract valuable light olefin products. This reduction factor recirculation naturally leads to the size reduction zone conversion MTO (1) because there are fewer of ethylene and propylene, which should be recycled through this zone. In addition, the present invention allows to hold significant amounts of reactive light olefins outside to the version of MTO, thereby increasing the stability there are catalytic system due to the removal of significant quantities of potential precursors of coke.
1. Process for the selective extraction containing dimethyl ether (DME) recirculation flow from the flow coming from the conversion of methanol to olefins (MTO), where the mentioned output stream contains water, methanol, dimethyl ether, ethylene, propylene,4-C6-olefins, and this method involves the following stages:
(a) cooling and separating at least part of the output stream of liquid water stream containing methanol and dimethyl ether, liquid hydrocarbon stream containing methanol, DME and C2-C6-olefins, and vaporous hydrocarbon stream containing DME, methanol, ethylene and propylene;
(b) distillation of dimethyl ether from at least part of the liquid hydrocarbon stream is separated in stage (a) in the zone of the distillation DME operating in the distillation conditions effective for the formation of vaporous head stream containing DME, methanol, ethylene and propylene, and liquid hydrocarbon grassroots thread, containing4-C6olefins;
(c) combining at least part of the gaseous hydrocarbon stream is separated in stage (a), with at least a part of the brain vapor stream produced in stage (b), with images is of enriched DME vaporous stream of light hydrocarbons;
(d) feeding the resulting enriched DME vaporous stream of light hydrocarbons in the area of primary absorption DME, where this vapor stream is introduced into contact with the containing methanol selective regarding DME solvent under conditions of wet cleaning, to make (1) liquid bottom stream of solvent containing methanol, DME, water, and a significant and undesirable quantities of ethylene and propylene, and (2) the head vaporous product stream enriched in light olefins and depleted DME;
(e) providing at least part of the liquid downstream of the flow is extracted from stage (d), in the zone of the distillation of light olefins, functioning in the distillation conditions effective for distillation of at least a significant part of ethylene and propylene contained in the liquid grassroots thread without Stripping out any significant parts of methanol, resulting in a head-stream of distant sections containing dimethyl ether, ethylene and propylene, and a liquid bottom stream containing DME, methanol, water and light olefins in the amount reduced in comparison with the content light olefins in the liquid downstream flow of the solvent supplied to this stage; and
(f) recycling at least part of the liquid downstream of the flow extracted at stage (e), in the conversion zone, logistics, selectively entering there,so additional oxygendemand the reactants.
2. The method according to claim 1, in which at least a portion of the flow of distant sections extracted at stage (e), served in the area of primary absorption DME.
3. The method according to claim 1, in which at least a portion of the flow of distant sections from stage (e) served in the area of secondary absorption DME, where it is introduced into countercurrent contact with other selective regarding DME solvent under conditions of wet cleaning, selected to create a depleted DME vapor head stream containing ethylene and propylene, and a liquid bottom stream containing DME, methanol and the solvent, and in which the resulting depleted DME vapor head flow combined with enriched in light olefins and depleted DME main product stream recovered from step (d) forming a stream of light olefin product which is withdrawn from the procurement process.
4. The method according to claim 1, which is used in stage (d) selective towards DME solvent contains from 80 to 99.99 wt.% of methanol.
5. The method according to claim 1, which is used in stage (d) conditions of wet cleaning include the mass ratio of solvent to a couple of from 1:1 to 3:1.
6. The method according to claim 3, in which areas of both primary and secondary absorption DME operate with methanol solvent and under conditions of wet cleaning, include the mass ratio of solvent to a couple of from 1:1 to 3:1.
7. The method according to claim 1, in which the fed to stage (d) the solvent is a part of the flow of the methanol feedstock supplied to the conversion zone logistics.
8. The method according to claim 2, which is used in stage (e) distillation conditions effective to increase the steam load on the zone of initial absorption of DME in size from 15 to 40 wt.%.
9. The method according to claim 3, in which the mass ratio of steam applied to the area of secondary absorption DME to the couple served in the area of primary absorption DME is from 0.15:1 to 0.4:1.
10. The method according to claim 1, which is used in stage (e) conditions of distillation set in such a way as to produce a liquid bottom stream containing less than 1 wt.% of ethylene.
FIELD: chemistry; obtaining of ethyl tert-butyl ether.
SUBSTANCE: ethyl tert-butyl ether is a high-octane component of engine fuel, made from hydrocarbon raw materials, containing isobutylene, and ethanol, containing more than 1% mass of water, including a column of heteroazeotrope fractional drying of ethanol using the obtained ethyl tert-butyl ether as the selective heteroazeotrope agent with output of dry ethanol, directed for obtaining ethyl tert-butyl ether in the lower heteroazeotrope distillation column and a mixture of ether, water and ethanol in the upper heteroazeotrope distillation column, with subsequent condensation of this mixture and splitting into two layers, with return of the upper layer into the heteroazeotrope distillation column and directing the water layer for separation of ethanol through distillation. The mixture of ether, water and ethanol is output from the upper heteroazeotrope distillation column in a quantity, determined from the formula G1=G2·Xe 2·n, where G1 is the quantity of the mixture of ether, water and ethanol, from the upper heteroazeotrope distillation column, in kg/hour, G2 is the quantity of ethanol, taken for drying in kg/hour, Xe is the concentration of water in ethanol, taken for drying in % mass and n is a coefficient, assuming values from 0.1 to 0.2. After condensation, of the mixture directed for splitting is cooled down to 10-40°C.
EFFECT: increased selectivity of the process.
5 cl, 5 ex
FIELD: obtaining of ether product.
SUBSTANCE: method involves reaction of iso-olefins of iso-olefin hydrocarbon raw materials with ethanol, using at least, one reaction-rectification system, with a middle reaction zone and upper and lower rectification zones. The initial ethanol is put between the upper rectification zone and the reaction zone. The ether product is tapped off from the lower part of the lower rectification zone. The used hydrocarbon fraction is taken from the upper part of the upper rectification zone in the form of azotrope with ethanol. The used hydrocarbon fraction is washed from ethanol, and the ethanol is separated from the washing water by rectification in form of azeotrope with water and the separated ethanol is returned to the reaction-rectification system. The azeotrope ethanol with water is put into the upper rectification zone, 5-15 plates higher than the point of input of initial ethanol. From the used hydrocarbon fraction, taken from the upper part of the upper rectification zone, water is taken out, containing ethanol, which is taken to the washing stage or to the stage of separating ethanol from washing water. The technical outcome is achieved due to lowering of the quantity of water on the catalyst of the process with ethanol, separated from the washing water.
EFFECT: increased efficiency of the process.
FIELD: processing of isobutene-containing hydrocarbon mixture and alcohol C1 or C2.
SUBSTANCE: proposed method includes joint chemical transformations of isobutene and said alcohol at forming of alkyl-tert-butyl ether, dimmers, trimmers, isobutene and probably codimmers and trimmers of isobutene with n-butenes in reaction zone (zones) at temperature ranging from 30 to 100 C in presence of highly acid solid catalyst and probably mixture of water at total molar ratio of alcohol to isobutene in flows fed to reaction zone (zones) equal to 0.1: 1 to 0.9:1; then flow containing mainly unreacted hydrocarbons C4 is separated from reaction mixture by rectification and subsequent rectification distillation of flow containing alkyl-tert-butyl ether and flow containing mainly isobutene dimmers from remaining reaction mixture (mixtures) is carried out; isobutene may be subjected to hydrogenation at maintenance of alcohol C1 or C2 in concentration of no less than 0.33 mass-% which is achieved through limitation of temperature and/or time of contact with catalyst and through delivery of additional amount of alcohol to last reaction zone; it is preferably to obtain content of alcohol no less than 0.5 mass-% but not exceeding its total amount permissible in target products and distilled with hydrocarbons C4 contained in said reaction mixture; during distillation of reaction products, pressure of from 0.025 to 0.15 Mpa and temperature in still (stills) of from 80 to 180 C shall be maintained.
EFFECT: possibility of depression of oligo- and polymerization of isobutene, thus reducing degree of catalyst deactivation.
14 cl, 3 dwg, 3 tbl, 14 ex
FIELD: petrochemical processes.
SUBSTANCE: invention is directed to processing of isobutene-containing hydrocarbon mixture preferably containing C4-hydrocarbons, which processing comprises interaction of isobutene contained therein with methanol in presence of acidic solid catalyst in one or several zones of synthesis of methyl tert-butyl ether followed by distilling off unreacted C4-hydrocarbons from reaction mixture, withdrawing, as more high-boiling residue, stream containing methyl tert-butyl ether, which is fully or partially supplied to ether decomposition zone, decomposing methyl tert-butyl ether in presence of high-acid solid catalyst, distilling off reaction products of stream preferably containing isobutene, methanol , and minor portion of non-decomposed methyl tert-butyl ether, withdrawing the rest of more high-boiling product containing predominantly methyl tert-butyl ether from the system or recycling it to ether decomposition zone, rectifying distilled-off stream predominantly containing isobutene, methanol, and minor portion of non-decomposed methyl tert-butyl ether, wherein stream mainly containing isobutene is distilled off and more highly boiling residue containing methanol and ether is subjected to additional rectification at lower pressure, recycling bottom residue containing mostly methanol to ether synthesis zone and distillate to distillation zone next after decomposition zone, recovering methanol by water extraction from mainly isobutene-containing stream, freeing washed isobutene stream from dimethyl ether by rectification, wherein stream containing dimethyl ether and isobutene is withdrawn as distillate and purified isobutene is recovered as more high-boiling bottom residue or, in case of heteroazeotropic drying of isobutene jointly with removal of dimethyl ether, stratifying resulting distillate and discharging water and hydrocarbon streams while recovering purified isobutene as more high-boiling bottom residue. Process is characterized by that decomposition of methyl tert-butyl ether is conducted at pressure assuring liquefied state of substances and temperature 60-120°C, stream obtained as distillate of rectification of washed out isobutene stream and containing dimethyl ether and isobutene or hydrocarbon stream containing dimethyl ether and obtained after stratification of distillate of heteroazeotropic drying of isobutene is recycled to methyl tert-butyl ether decomposition zone.
EFFECT: reduced formation of dimethyl ether and increased productivity of plant.
2 dwg, 9 tbl, 9 ex
FIELD: industrial organic synthesis and catalysts.
SUBSTANCE: invention provides a method for processing methanol into dimethyl ether and liquid hydrocarbons, the latter being used as high-octane components of gasolines Ai-92, 95. Processing comprises contacting of raw material, in at least one step, in at least one reactor containing catalyst: Pentasil-type zeolite and binder, followed by cooling resulting products, condensation and separation thereof to isolate methanol conversion hydrocarbon gases, water, and desired products, after which cooled hydrocarbon gases are recycled to methanol conversion stage in at least one reactor. Catalyst is characterized by SiO2/Al2O3 molar ratio 20-100, content of sodium oxide not higher than 0.2%, and additionally contained silicon dioxide and zirconium dioxide at following proportions of components: 1.0-15.0% silicon dioxide, 1.0-5.0% zirconium dioxide, 20-70% zeolite, and binder - the balance.
EFFECT: increased yield of desired products and improved performance characteristics of catalyst.
4 cl, 5 tbl, 18 ex
FIELD: petrochemical industry; method of reprocessing of the hydrocarbon mixture containing isobutene.
SUBSTANCE: the invention is pertaining to the field of petrochemical industry, in particular, to the method of reprocessing of the hydrocarbon mixture containing isobutene. The invention provides, that conduct the chemical transformation of isobutene and non-tertiary alcohol (alcohols) in the reactionary zone (zones) at presence of the solid acid catalyst at the temperature of 30-100°C predominantly in the alkyl-tret.butyl ester (esters) and isobutene dimers. Then from the reaction mixture distill at least hydrocarbons C4 in the rectification zone and it is possible to use the subsequent hydrogenation of the formed isobutene dimers. At that in the reactionary zone (zones) as the source substances feed the non-tertiary alcohol (alcohols) and isobutene in the hydrocarbon mixture in the molar ratio from 0.1 up to 0.9 and hold the temperature and the time of the contact to the catalyst providing transformation of the major part of the alcohol (alcohol) into the alkyl-tret.butyl ester (esters) and not resulting in the domination of the reverse reaction of decomposition of the formed epy alkyl-tret.butyl ester (esters) in the end of the reaction zone and to the significant increase of the amount of the non-tertiary alcohol (alcohol) in the gating out of it stream. The technical result of the invention is the increased quality of the final product.
EFFECT: the invention ensures the increased quality of the final product.
15 cl, 3 dwg, 10 ex
FIELD: petrochemical industry, chemical technology.
SUBSTANCE: invention relates to a method for combined synthesis of methyl-tert.-butyl and methylisobutyl esters that are used as high-octane additive to motor fuels. Method involves treatment of isobutylene-containing fraction with methanol in liquid phase at heating, under pressure, in the presence of sulfocation-exchange resin in H+-form as a catalyst. Then reaction products are separated in fractionating column wherein dimethyl ether and isobutanol are added additional to the raw composition in the following mole ratio of components: methanol : isobutylene : dimethyl ether : isobutanol = (0.71-0.82):1:(0.21-0.33):(0.21-0.33), respectively, and treated in liquid phase. Temperature in the reaction zone is maintained in the range 50-70°C and pressure - 1.6 mPa. Invention provides the possibility for simultaneous synthesis of different esters and simplifying the process.
EFFECT: improved preparing method.
1 tbl, 2 dwg, 5 ex
FIELD: petroleum chemistry, chemical technology.
SUBSTANCE: method involves processing hydrocarbon raw comprising as minimum tert.-pentenes and other C5-hydrocarbons to yield one or some high-octane products comprising alkyl-tert.-pentyl ester wherein methyl or ethyl represents alkyl. Method involves liquid-phase chemical interaction of tert.-pentenes with methyl alcohol or ethyl alcohol in the presence of acid solid catalyst at 25-100°C for two steps and intermediate distillation of hydrocarbons. At the first step conversion of tert.-pentenes is 40-88% and at this step 80% of C5-hydrocarbons, not less, is distilled off from the reaction mixture, among them the greater part of unreacted 2-methyl-butene-2 and, preferably, the greater part of alcohol and with removal of high-octane residue wherein the concentration of alkyl-tert.-pentyl ester exceeds as minimum the total concentration of C5-hydrocarbons. At the second step in distillate obtained at the first step, possibly, with additional addition of alcohol and/or hydrocarbon raw comprising tert.-pentenes and/or hydrocarbon raw comprising isobutene method involves conversion of 40% tert.-pentenes feeding to the second step and high-octane flow is prepared wherein the total concentration of C5-hydrocarbons exceeds the concentration of alkyl-tert.-pentyl ester. Invention provides simplifying technology of the process.
EFFECT: improved method of processing.
11 cl, 3 dwg, 1 tbl, 11 ex
FIELD: industrial organic synthesis.
SUBSTANCE: high-purity dimethyl ether is obtained via dehydration of methanol in presence of sulfo-ionite catalyst at 110-150°C and pressure 4.9-13.2 atm gauge in combined reaction-rectification apparatus composed of two rectification zone and one middle reaction zone filled with catalyst. Methanol is fed to catalyst zone or to lower rectification zone. It is possible to dispose reaction and rectification zone both inside the same apparatus and separately in two or three apparatuses so to conduct a single reaction-rectification process. Desired ether is recovered from the top of apparatus. A part of dimethyl ether containing impurities is discharged from lower part of higher reaction zone in side withdrawal point corresponding to 1-10 theoretical plate (going from the bottom of rectification column).
EFFECT: improved quality of product.
2 cl, 3 dwg, 3 ex
FIELD: organic chemistry, chemical industry in particular distillation of organic substance mixtures.
SUBSTANCE: dimethyl ether of high purity is obtained from reaction mixtures in process of synthesis of dimethyl ether from carbon oxide, carbon dioxide and hydrogen, or simultaneous synthesis of dimethyl ether with methanol, or methanol dehydration. Dimethyl ether in recovered from reaction mixture in distillation column under pressure with dimethyl ether discharge. Dissolved gases are removed in stripping column before feeding into distillation column. Pressure in stripping column is maintained in limits of 7-31 ata. As stripping column plate-type column or packed column is used. In packed column conditions sufficient for phase inversion are maintained. Dimethyl ether is discharged in form of distillate and/or in form of upper side cut with or without admixture discharge.
EFFECT: decreased carbon dioxide content in finished product, increased dimethyl ether yield.
5 cl, 7 tbl, 4 dwg, 6 ex
FIELD: rectification of organic compounds.
SUBSTANCE: all-purpose installation enables purification of high-boiling vacuum rectification solvents, in particular ethylene glycol, monoethanolamine, methyl cellosolve, ethyl cellosolve, butyl cellosolve, N-methylpyrrolidone, and benzyl alcohol.
EFFECT: enhanced purification efficiency.
8 cl, 1 dwg, 7 tbl, 7 ex
SUBSTANCE: invention pertains to the method of obtaining 2-methyl-2-butene from isopentane, including gas phase dehydrogenation of isopentane in the dehydrogenation zone, extraction of the C5-fraction from contact gas, mainly consisting of isopentane, tert pentanes, isoprene impurities and other hydrocarbons and obtaining a stream from it, mainly consisting of 2-methyl-2-butene, with use of a liquid phase isomerisation catalyst in a C5-fraction 2-methyl-1-butene in 2-methyl-2-butene and distillation. The method is characterised by that, the above mentioned C5-fraction, possibly containing extra piperylene and 2-pentene, directly or after distillation from the larger part of 2-methyl-2-butene, undergoes liquid phase hydroisomerisation in the presence of a solid catalyst, containing group VIII metal(s), capable of simultaneous catalysing hydrogenation of pentadienes, isoprene and possibly, piperylenes, and positional isomerisation of tert pentenes, preferably with subsequent additional isomerisation of 2-methyl-1-butene in 2-methyl-2-butene on a sulfocationite catalyst, and distillation with output of a distillate stream of mainly isopentane, containing not more than 1.0% mass, preferably not more than 0.2% mass of pentadiene(s), which are mainly recirculated in the hydrogenation zone, and output from the lower part of the recirculation stream of mainly 2-methyl-2-butene with impurities of n.pentane and possibly 2-pentenes. The invention also pertains to the method of obtaining isoprene from isopentane, which involves reaction of 2-methyl-2-butene, obtained from gas phase dehydrogenation of isopentane, with hydroperoxide with further conversion of the oxide or products of hydroxylation in isoprene.
EFFECT: obtaining 2-methyl-2-butene and isoprene from isopentane.
13 cl, 8 ex, 2 tbl, 3 dwg
FIELD: industrial organic synthesis.
SUBSTANCE: production of styrene is effected via gas-phase dehydration of 1-phenylethanol at elevated temperature in presence of dehydration catalyst including molded particles of alumina-based catalyst having BET surface area 80 to 140 m2/g and pore volume (Hg) above 0.65 ml/g.
EFFECT: reduced amount of by-products and prolonged service cycle of catalyst.
3 cl, 1 tbl, 5 ex
FIELD: one-stage production of isoprene.
SUBSTANCE: proposed one-stage production method includes continuous or cyclic delivery of isobutylene and/or tert-butanol, formaldehyde and water to aqueous acid solution and interaction of reaction mixture at distillation of mixture containing isoprene to be produced, water, unreacted starting materials and other low-boiling components from reaction mixture beyond reaction system where said reaction is conducted at regulation of concentration of high-boiling byproducts which are accumulated in said reaction mixture at interval of from 0.5 to 40 mass-%.
EFFECT: enhanced efficiency.
10 cl, 2 dwg, 1 tbl, 13 ex