The way to obtain olefinic hydrocarbons

 

Usage: petrochemistry. Essence: olefinic hydrocarbons obtained by dehydrogenation of paraffin hydrocarbons in a fluidized bed of particulate catalyst circulating in the reactor - regenerator. The method includes preparation of a hydrocarbon mixture from the forward and recycle streams paraffin hydrocarbons, evaporation, heating vapor by the heat contact of gas and overheated vapors of the hydrocarbons in the furnace, followed their direction to dehydrogenation in a fluidized bed of catalyst, the contact cooling of the gas in the HRSG burning of coke in the process of oxidation catalyst oxygen in the regenerator, the recovery of the catalyst natural gas, the desorption of the reaction products and the recovery of the catalyst with an inert gas, the transportation of the catalyst from the reactor to the regenerator and back, compressing gas contact, condensation and separation of fractions of paraffinic and olefinic hydrocarbons from hydrocarbon condensate by distillation. Thus maintain the oxygen content in the recovered catalyst fed to the reactor, within 0,025-0,075 wt.% by tipperariana catalyst with an inert gas supplied in the amount of 0.25 to 1.25 nm3/m is the torus flow of inert gas is reduced. Effect: increase the efficiency of the process of dehydrogenation of paraffin hydrocarbons, reducing losses of raw material and catalyst, reducing energy consumption. 2 C.p. f-crystals, 4 tab., 1 Il.

The invention relates to the field of production of olefinic hydrocarbons obtained from paraffin hydrocarbons by dehydrogenation in a fluidized bed of catalyst and used for the synthesis of isoprene, ethers or other organic products and can be used in the petrochemical industry.

There is a method of dehydrogenation of paraffin hydrocarbons, such as isobutane, butane, by passing superheated vapors of the hydrocarbons through the layer of fluidized pulverulent alimohammadi catalyst at a temperature of 550-610oWith, including the regeneration of the catalyst at a temperature of not more than 680oWith the oxidation of trivalent chromium to hexavalent content of 0.5-1.0% and then recover natural gas before reaching the content of hexavalent chromium of 0.1-0.2% in the recovered catalyst and sent to the reactor, where at an absolute pressure of 0.12 to 0.13 MPa carry out the dehydrogenation of paraffin hydrocarbons, and selectivity process).

The disadvantage of this method is unsatisfactory desorption of the recovered catalyst from the reaction products recovery and oxygen in the air supplied to the burning of coke in the process of oxidation of the catalyst caused by the lack of information about the content of oxygen in the catalyst.

In addition, the desire to carry out intensive desorption of reaction products from the catalyst withdrawn from the reactor to the regenerator, requires increased flow of inert gas (nitrogen), which contributes to the reactions of pyrolysis of target products, increased coke formation, especially at low loads on raw.

The lack of complete information about the process of regeneration of the catalyst, the uncontrolled flow of inert gas, particularly in the impulse line measuring devices, lead to significant performance losses of raw materials, reaching 30-50 kg/t of olefinic hydrocarbon.

The closest in technical essence to the proposed method of obtaining olefinic hydrocarbon is a method for the dehydrogenation of paraffin hydrocarbons in a fluidized bed of particulate catalyst, which consists in evaporating a mixture of direct and return paraffin hydrocarbon and in which m is heated by the heat contact of the gas in the quenching coils of the reactor to 150oWith and overheating 550oWith in the furnace by the heat of the flue gas, in the subsequent direction of the vapor of the raw material in the reactor circulating in the reactor-regenerator catalyst and carrying out the dehydrogenation of paraffin hydrocarbons at a temperature of 580-590oC and space velocity of the raw material 120-180 h-1and the pressure in the reactor 0,125 MPa, which is also the output supereeego catalyst in the regenerator for burning coke and restore the activity of the catalyst at a temperature of 640-650oAnd pressure 0,117 MPa in the presence of air, in the subsequent desorption of the nitrogen product recovery catalyst natural gas supplied to transfer excess hexavalent chromium to trivalent, which also includes contact cooling gas compression, condensation and separation of fractions of paraffinic and olefinic hydrocarbons by distillation of the hydrocarbon condensate and returning the unreacted recycle paraffin hydrocarbon after binding of olefinic hydrocarbons contained in the fraction, prepared from a hydrocarbon mixture of direct and recycle stream of the paraffin hydrocarbon (P. A. Kirpichnikov, in. A. Beresnev, L. M. Popova. Album technological of this method is the lack of information about the oxygen content in the recovered regenerated catalyst, the process of dehydrogenation at suboptimal concentrations of the Ingaz (nitrogen) in the contact gas, which leads to lower yields of the target product on the decomposed raw material for 2-3 wt.%. In addition, in the known method using recycle stream of unreacted paraffin hydrocarbon containing products of organic synthesis using olefinic hydrocarbons, in particular esters. Their content is limited mainly depending on the capabilities of the hardware allocation return paraffin hydrocarbon without the influence of organic synthesis products on the activity alimohammadi catalyst loaded in the system of the reactor-regenerator. This causes a sharp drop in the content of hexavalent chromium in oxidized catalyst, its coking, the poor performance of the reactors, the overestimation of the temperature in the reactor-regenerator, increases the abrasion of the catalyst and increasing the unit cost of the catalyst, increasing energy consumption.

The aim of the invention is to increase the efficiency of the process of dehydrogenation of paraffin hydrocarbons, reducing losses of raw material and catalyst, reducing energy consumption.

This goal is achieved by those who ipaam layer of pulverulent catalyst, circulating in the reactor-regenerator, comprising preparing a hydrocarbon mixture of direct and recycle streams paraffin hydrocarbons, evaporation, heating vapor by the heat contact of gas and overheated vapors of the hydrocarbons in the furnace, followed their direction to dehydrogenation in a fluidized bed of catalyst, which also includes contact cooling gas in the HRSG burning of coke in the process of oxidation catalyst oxygen in the regenerator, the recovery of the catalyst natural gas, the desorption of the reaction products and the recovery of the catalyst with an inert gas, the transportation of the catalyst from the reactor to the regenerator and back to the compression of the contact strip, condensation and separation of fractions of paraffinic and olefinic hydrocarbons from hydrocarbon condensate by distillation additionally maintain the oxygen content in the recovered catalyst fed to the reactor, within 0,025-0,075 wt. % by tipperariana catalyst with an inert gas supplied in the amount of 0.25 to 1.25 nm3/m3circulating catalyst, and by increasing the oxygen content in the recovered catalyst flow rate of the inert gas increases, and the and used as a recycle stream, for example, return isobutane fraction or return isopentanol fraction drawn from the process of synthesis of esters derived from olefinic hydrocarbons and alcohol, the content of the ester in a hydrocarbon mixture of direct and recycle streams paraffin hydrocarbons is kept in the range from 0.01 to 0.05 wt.%.

The content of the inert gas in contact with gas withdrawn from the reactor, maintained preferably within 0.5 to 1.5 wt.% In contrast to the known method of producing olefinic hydrocarbons proposed method due to the availability of information about the content of oxygen in the circulating catalyst after recovery of hexavalent chromium to trivalent to make tipperariana catalyst with an inert gas to a condition in which remaining after desorption of oxygen will not lead to a significant loss of raw material in the dehydrogenation of paraffin hydrocarbons, and consumption of Ingaz on tipperariana (desorption) must not exceed the number violating the normal circulation of the catalyst in the reactor-regenerator and the supply of heat for the endothermic dehydrogenation process. This method will allow unlike known to reduce the loss of raw material 30 is W, supplied to the evaporator, esters content in the range from 0.01 to 0.05 wt.% allow for the separation of air and return paraffin at rectification with minimal energy costs and dehydrogenation of hydrocarbons with a maximum permissible content of coke in splenorenal the catalyst withdrawn from the reactor by burning coke and oxidation catalyst in the regenerator. Thanks to this mixture of paraffin hydrocarbons fed to the evaporator does not fall in catalyst activity and performance installation dehydrogenation.

As for the content of inert gas (nitrogen) in the contact gas, in contrast to the known method, when the nitrogen content reaches of 3.0-5.0 wt.%, sharp restriction of nitrogen supplied to the desorption of reaction products from the catalyst withdrawn from the reactor to the regenerator, and poddevku pulse in line measuring devices installed to control the operation of the reactor, can significantly reduce the proportion of the pyrolysis process compared to the process of catalytic dehydrogenation and reduce the consumption of abhasa of the allocation process fraction of the paraffin and olefin hydrocarbons. As a result of such technical reception quantity of paraffin techniques in the invention not only achieve savings of raw materials and reduce energy consumption, but also significantly improve the safety of plant operation, prevent local overheating of the catalyst, the formation of small fractions, carry out contact or flue gas, reducing catalyst losses at 3-5 kg/t of olefinic hydrocarbon.

The proposed method is as follows (drawing).

A pair of paraffin hydrocarbons from the evaporator is sent to the superheater, hardening coils and superheating furnace (not shown) with a temperature of 520-550oWith on line 1 under a distribution grid 2 reactor 3 for the dehydrogenation of hydrocarbons. The catalyst in reactor 3 enter catalyzatoroprovod 4 from the regenerator 5. Received contact the gas is cooled in the quenching reactor coils 3 pairs of raw materials, then cleaned catalyst dust in a group of cyclones (not shown) and output on lines 6 through the HRSG, where the contact gas is used as the fluid in the receiving water vapor, then it is sent to the scrubber, irrigated with water to remove catalyst dust and served on the suction side of the compressor (not shown). Superagency catalyst that has lost the necessary activity, directed on catalyzatoroprovod 6 from the reactor 3 in the regenerator 5 ohne oxidation regenerator, where along the lines 7 served in the air and on line 8 fuel gas to maintain the desired regeneration temperature. The oxidized catalyst from the oxidation zone of the display in the reduction zone, where it is treated with natural gas, preferably containing methane. Natural gas for recovery of the catalyst and the translation of hexavalent chromium to trivalent serves on line 9, and an inert gas to tipperariana catalyst (desorption products of oxidation and reduction) direct on line 10. The transportation of the catalyst from the reactor 3 in the regenerator 5 is carried out using a carrier gas (Ingaz, air) supplied through the line 11, and desorption of the catalyst from the reaction products is carried Ingaz supplied through the line 12. Transportation of catalyst from the regenerator 5 in the reactor 3 is carried out with the help of Ingaz and/or vapors paraffin hydrocarbons fed to the dehydrogenation sent via line 13. Flue gas from the regenerator 5 output line 14 in waste heat boilers, then through a scrubber, irrigated with water, dropping through the water seal in the atmosphere (not shown). Feeding a fresh catalyst into the system are carried out by the line 15.

The temperature of the dehydrogenation process of parafi the ru catalyst regeneration 600-650oC. as the catalyst use powdered lomography catalyst type THEM-2201, PCA, AOK, etc.

In contrast to the known method in the proposed monitor the oxygen content in the recovered catalyst is withdrawn from regenerator 5 in the reactor 3. The oxygen content in the recovered catalyst fed to the reactor, maintain within 0,025-0,075 wt.% by tipperariana catalyst with an inert gas supplied in the amount of 0.25 to 1.25 nm3/m3circulating in the reactor-regenerator catalyst, and by increasing the oxygen content in the recovered catalyst flow rate of the inert gas increases, and decreasing the oxygen content in the recovered catalyst flow rate of inert gas is reduced.

This makes the process of dehydrogenation of paraffin hydrocarbons is carried out in optimal conditions, with an insignificant share of oxidative pyrolysis of raw materials and a small loss of the target product.

When used as a recycle stream, for example, return isobutane or return isopentanol faction, their output processes for the synthesis of esters derived from olefinic hydrocarbons contained in ol is in the paraffin hydrocarbons is kept in the range from 0.01 to 0.05 wt.%. This prevents the drop in catalyst activity due to its supervivencia and provide almost complete oxidation contained in the feedstock esters oxygen adsorbed on the catalyst surface, the input of the regenerator to the reactor. The use of mixtures with a high content of esters to a strong drop in catalyst activity and adhesion of particles, followed by the formation of agglomerates of the catalyst and zabawkami of catalyzatoroprovod.

The content of the inert gas in contact with gas withdrawn from the reactor, maintained preferably within 0.5 to 1.5 wt. %. This provides a reduction of less selective share homogeneous process, followed by pyrolysis, and is especially effective when using inert gas obtained from air method of reducing fuel gas with subsequent cleaning of flue gas from a carbon dioxide or without it.

Purged from the catalyst dust and cooled the contact gas is directed to compression, condensation, allocate a fraction of paraffinic and olefinic hydrocarbons and hydrocarbon condensate by distillation. Alafinova-paraffin fraction is used in the process of manufacturing esters, dioxane alcohols, and you shall recycle streams, applied to the dehydrogenation of paraffin hydrocarbons in dust almograve catalyst (not shown).

The method is illustrated by the following examples.

Example 1 the Dehydrogenation of isobutane to isobutylene carried out by a known method on the catalyst IM-2201 at the space velocity of the feedstock 150 h-1temperature 580oC and the pressure in the reactor 0,125 MPa (0,25 MPa) regeneration of the catalyst is carried out at a temperature of 640oAnd pressure 0,117 MPa (0,17 MPa). As a source of raw materials use a mix of direct and recycle streams paraffin hydrocarbons of the following composition, wt.%: isobutane 97,9; isobutylene 1,2, hydrocarbons3N. butane to 0.9. Deformirujuschij agent is nitrogen. Feeding a fresh catalyst 1% from circulating in the system.

Main indicators of the process of dehydrogenation Feed isobutane fraction to dehydration, t/h 25,0 superheat Temperature vapor of the raw materialoC - 546 process Temperature dehydrogenation,oWith: On top of the grate reactor - 580 On average lattice reactor - 558 On the bottom grate reactor 555 temperature of the contact of the gas after quenching coil,oC - 475
The nitrogen content in the contact gas, wt.% - 3,9
The content of oxygen In the missed fraction iC4- 37,3
On the unfolded fraction iC4- 81,1
Conversion, % - 46,0
Air consumption for regeneration of the catalyst, nm3/h - 15000
The content of the coke in the catalyst, wt.%:
Before regeneration - 0,10
After regeneration - 0.04
The content of hexavalent chromium after oxidation catalyst, wt.%: - 0,45
The content of hexavalent chromium after recovery of the catalyst, wt. % - 0,10
Nitrogen flow on tipperariana catalyst (desorption glass regenerator), nm3/h - 45,0
The flow of catalyst, kg/t of isobutylene - 24,0
The flow rate of isobutane per 1 ton of isobutylene taking into account losses in the allocation isobutane-isobutilene fraction, t - 1,270
The flow rate of isobutane per 1 ton of isobutylene in the isobutane-isobutilene fraction without loss of hydrocarbons during selection, t - 1,233
Examples 2-4.

Dehydrogenation of isobutane to isobutylene implement the proposed method on the catalyst IM-2201, volumetric feed rate 150 h-1. Reactor pressure of 0.14 MPa (0,4 MPa) the pressure in the regenerator 0,126 MPa (0,26 ATI). As a source of raw materials use a mix of direct and recycle streams paraffin hydrocarbon composition, wt.%: the of 97.8 isobutane; isobutylene 1,3 hydrocarbons With3N. butane to 0.9. Desorber the d n tipperariana catalyst in the regenerator 50-250 nm3/PM

Main indicators of the process of dehydrogenation see table.1.

Examples 5-7
Dehydrogenation of isobutane to isobutylene is carried out with the proposed method. The dehydrogenation conditions similar to those shown in examples 2-4. The nitrogen content in the contact gas was changed in the range of 0.5-1.5 wt.%. Feed isobutane fraction was 25 t/h, temperature overheating of raw materials, process of dehydrogenation and regeneration identical to those given in examples 2-4. The flow of inert gas to tipperariana catalyst withdrawn from the regenerator, 0,75 nm3/m3circulating catalyst, the oxygen content in the recovered catalyst is 0.05 wt.%.

The main quality parameters of the process of dehydrogenation see table.2.

Examples 8-10.

Dehydrogenation of isobutane to isobutylene is carried out with the proposed method. The modes of the process of dehydrogenation of isobutane and regeneration of the catalyst is similar to example 3. The composition of raw materials characterized by the presence of methyl tertiary butyl ether, input return isobutane (recycle stream), warded off by distillation of methyl tertiary butyl ether derived from isobutylene contained in the isobutane-isobutilene fraction and methanol on the catalyst KU-23 which when elevated levels of methyl tertiary butyl ether isobutane fraction (a mixture of direct and recycle streams) up to 0.10 wt.% the outputs of isobutylene fall to 2 abs.%.

Examples 11-12.

Dehydrogenation of isopentane spend on offer (example 11) and a known manner (example 12) on almograve catalyst IM-2201. Deformirujuschij agent is nitrogen. Feeding a fresh catalyst was 0.8% from circulating in the regenerator-reactor. The composition of isopentanol fraction fed to the dehydrogenation, wt.%: isopentane 98,1; isoamylene 1,4.

Main indicators of the process of dehydrogenation see table.4.

As can be seen from the examples, the use of the proposed method of producing olefinic hydrocarbons can reduce the specific consumption of raw materials 30-40 kg/t of olefinic hydrocarbons, reduces the amount of catalyst 3-6 kg/t of olefinic hydrocarbons, and also increases the production of 4-7%.


Claims

1. The way to obtain olefinic hydrocarbons by dehydrogenation of paraffin hydrocarbons in a fluidized bed of particulate catalyst circulating in the reactor - regenerator, comprising preparing a hydrocarbon mixture of direct and recycle streams paraffin hydrocarbons, evaporation, heating vapor by the heat contact of gas and overheated vapors of the hydrocarbons in the furnace, followed their direction Degi the YIG coke in the oxidation catalyst oxygen in the regenerator, recovery of catalyst natural gas, the desorption of the reaction products and the recovery of the catalyst with an inert gas, the transportation of the catalyst from the reactor to the regenerator and back, compressing gas contact, condensation and separation of fractions of paraffinic and olefinic hydrocarbons from hydrocarbon condensate by distillation, characterized in that withstand the oxygen content in the recovered catalyst fed to the reactor, within 0,025-0,075 wt.% by tipperariana catalyst with an inert gas supplied in the amount of 0.25 to 1.25 nm3/m3circulating catalyst, and by increasing the oxygen content in the recovered catalyst flow rate of the inert gas increases, and decreasing the oxygen content in the recovered catalyst flow rate of inert gas is reduced.

2. The method according to p. 1, characterized in that when used as a recycle stream, for example, return isobutane fraction or return isopentanol fraction drawn from the process of synthesis of esters derived from olefinic hydrocarbons and alcohol, the content of the ester in a hydrocarbon mixture of direct and recycle streams paraffin hydrocarbons withstand the om gas, the output from the reactor, maintain, preferably in the range of 0.5-1.5 wt.%.

 

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FIELD: regeneration of heat and extraction of impurities.

SUBSTANCE: the invention is pertaining to the method of regeneration of heat and extraction of impurities from the area of the heat-producing reaction in the fluidized flow, conducted for conversion into light olefins of oxygenates present in the flow of the oxygenate (oxygen-containing) raw. raw. The offered method includes the new system of a two-stage quick chilling intended for extraction at the first stage of water from the outgoing from the reactor flow and regeneration of heat of this flow for the purpose, at least, of the partial evaporation of the raw flow due to indirect heat-exchange between the oxygenated raw and the flow of the upper product of the first stage or the flow of recirculation of the first stage. The flow of purification being withdrawn from the first stage, contains the large share of impurities and the high-boiling oxygenates. In the second stage besides conduct extraction of water from the products flow containing light olefins, and produce the flow of the purified water, which requires only the minimum evaporation of the water for production of the water flow of the high degree purification. The method allows to concentrate the impurities in a rather small flow and ensures the significant saving of power and money resources at production of a flow of the vaporous raw guided into the area of realization of the heat-exchange reaction in the fluidized flow.

EFFECT: the invention ensures concentration of the impurities in a rather small flow and the significant saving of power and money at production of the flow of the vaporous raw directed into the area of realization of the heat-exchange reaction in the fluidized flow.

19 cl, 3 tbl, 4 dwg, 5 ex

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