FIELD: organic chemistry.
SUBSTANCE: invention refers to enhanced method of propane and/or butanes flow separation from original hydrocarbons containing alkylmercaptan impurities by means of fractional distillation resulted in liquid phase and separated flow from column head at pressure providing that separated flow from column head containing propane and/or butanes has temperature within 50 to 100°C, including (i) addition to specified origin hydrocarbons an amount of oxygen sufficient for mercaptan oxidation, (ii) fractional distillation of produced mixture containing at least one catalyst layer oxidising mercaptans to sulphur compounds with higher boiling temperatures and (iii) separation of sulphur compounds with higher boiling temperatures as portion of distillation liquid phase.
EFFECT: improved method of propane and/or butanes flow separation from of original hydrocarbons by means of fractional distillation resulted in liquid phase and separated flow.
8 cl, 2 tbl, 1 dwg, 1 ex
The present invention relates to the desulfurization and, in particular, to desulphurization hydrocarbon streams.
Natural gas contains a variety of hydrocarbons, predominantly saturated, together with impurities, particularly sulfur compounds. It is often desirable separation of the flow of hydrocarbons into fractions. C2and higher hydrocarbons, as a rule, separated from methane by liquefaction, and the resulting fluid flow in the future liquefied natural gas, may be separated into fractions, such as ethane, propane, butane and a stream of higher hydrocarbons, hereinafter referred to as the gasoline fraction. In some cases, it is desirable separation of the flow of butane to n-butane and ISO-butane.
The separation into fractions is usually by means of fractional distillation, in which the source of the hydrocarbons is introduced into a column for fractional distillation. Between the upper and lower part of the column is set to the temperature gradient, so that the more volatile components are separated in the form of a gas stream from the head of the column, while the less volatile components are released from the bottom of the column in the form of fluid flow. Column usually works with the heat supplied to the bottom edge of the column by boiling part of the separated liquid stream, and return isprev is Asa liquid in the column. Similarly, the flow of steam from the upper part of the column is cooled to the condensation of a part of it. The condensate is returned to the upper edge of the column.
The separation of liquefied natural gas is often carried out in several stages. In the first stage, the ethane is separated in the form of a stream from the head of the column, in the first column, called deethanization, obtaining a liquid stream containing C3and higher hydrocarbons. This stage is usually carried out at elevated pressure, cooling for the condensation of a liquid phase. The liquid stream containing C3and higher hydrocarbons, is then entered in the second column, called depropanizer, in which the propane is separated in the form of a gas phase from the head of the column. The resulting stream of liquid hydrocarbons and depleted in C3then enter in the next column, called debutanizer, where butane is separated from the higher hydrocarbons in the form of a stream from the head of the column. Higher hydrocarbons to form a gasoline fraction. As indicated above, in some cases, the flow of butane can be separated into normal and isobutane through a separating column for butane so that water could be used to effect the cooling flow from the head of the column in depropanizer and debutanizer (and in the separating column for butane, is if it is used), distillation is carried out under such high pressure that the temperature of the vapor introduced into the condenser at the head of the column, is a temperature in the range of from 50 to 100°C.
Natural gas typically contains many sulfur compounds, including hydrogen sulfide, carbondisulfide, allylmercaptan, alkylsulfate and disulfides. Boiling point, at atmospheric pressure, common impurities containing sulfur and paraffin presents forth in the following table.
|Material||The boiling point at atmospheric pressure (°C)|
|The hydrogen sulfide||-42|
|The ethyl mercaptan||35|
|Other sulfur compounds||>50|
Thus, sulfur compounds have a specific range of boiling points, and thus, depending on their volatility, should, as the government is about, be separated together with the corresponding fraction of hydrocarbons. Thus, the streams of ethane and propane, as a rule, must contain impurities of hydrogen sulfide, carbondisulfide and methylmercaptan. The flow of butane should, as a rule, contain impurities methyl - and ethyl mercaptan and dimethyl sulfide. If you are using a separating device for butane, methyl mercaptan will be separated together with the stream of isobutane and ethyl mercaptan and dimethyl sulfide together with a stream of n-butane. Gasoline fraction will contain impurities methyl - and ethyl mercaptan, dimethyl sulfide and higher sulfur compounds.
The presence of sulfur compounds in different fractions, as a rule, is undesirable, since sulfur compounds give a distinctive odor, and can make a faction corrosive and/or poisons the catalysts used in the further processing of the fraction.
The hydrogen sulfide and carbondisulfide can easily be removed from natural gas by means of an appropriate pre-processing stage. So, natural gas can pass through the material, which will hydrolyze carbondisulfide to gaseous carbon dioxide and hydrogen sulfide. The hydrogen sulfide and, if desired, the carbon dioxide can be removed by appropriate absorption technology. So, can be used "wet" SP is the event, in which the hydrogen sulfide and carbon dioxide are absorbed by the corresponding regenerated absorbing liquid, such as diethanolamine. Alternatively, the hydrogen sulfide can be removed using the appropriate solid absorbent, such as zinc oxide. The removal of mercaptans, sulfides and disulfides delivers more problems.
Mercaptans and other sulfur compounds can be removed by hydrodesulfurization conversion of sulfur compounds to hydrogen sulfide, with the subsequent removal of hydrogen sulfide using conventional methods of absorption, as described above. However, as a rule, is inconvenient to expose the flow of raw materials natural gas or liquefied natural gas hydrodesulfurization before fractionation or expose every faction hydrodesulfurization and hydrogen sulfide removal.
It is known that mercaptans can interact with oxygen in the presence of a catalyst, with the formation of disulfides and water. This method can be used in industry for cleaning sulphur fluid hydrocarbons, such as butane, diesel fuel and kerosene. In the present invention the catalytic oxidation is carried out in the distillation process, so that the mercaptans are oxidized to sulfur compounds with higher boiling points and, therefore, as great the second part, become a part of the flow of gasoline. This thread may be hydrodesulfurization and separation of hydrogen sulfide, if required.
Catalytic distillation of hydrocarbons for the removal of sulfur compounds proposed in international application WO 97/03149. However, in this link the flow of oil is subjected to hydrodesulfurization by way catalytic distillation, so that the organic sulfur compounds are converted to hydrogen sulfide, which is removed in the form of a vapor stream from the head of the column. In contrast, in the present invention, the sulfur compounds are oxidized and separated as part of the liquid stream.
Accordingly, the present invention provides a method of separating a stream containing propane and/or butane, from the original hydrocarbons containing impurities of allylmercaptan by fractional distillation at such pressure that the separated flow from the head of the column containing the specified propane and/or butane, is at a temperature in the range from 50 to 100°C, including the introduction of these original hydrocarbons in the amount of oxygen sufficient to oxidize the mercaptans in them, and the impact on the resulting mixture fractional distillation column containing at least one layer of a catalyst capable of under the prevailing conditions, oxidation of measures is of Aptana to sulfur compounds with higher boiling points, and the separation of sulfur compounds with higher boiling points as part of the liquid phase from the distillation.
By way of oxidation of mercaptans such as methyl mercaptan and ethyl mercaptan, are oxidized to the corresponding disulfides, which have a boiling point at atmospheric pressure exceeding 100°and thus, instead of distillation as part of the flow of propane and/or butane from the head of the column will remain in the fluid flow. Another advantage of the method according to the present invention is that the mercaptans, in particular methyl mercaptan, can be formed in a cube with return phlegmy by disproportionation of other sulfur compounds. For this reason, the method according to the present invention can remove these mercaptans, when they are formed.
The number of mercaptans present in the original hydrocarbons will typically be less than 2000 mlnd, and generally will be in the range from 100 to 1000 mlnd by volume. Typically, half of all present mercaptans will represent methyl and ethyl mercaptan. Thus, the amount of oxygen required for oxidation, is usually relatively small, and when used pressure source hydrocarbons can dissolve a quantity of air sufficient for baking and such amount of oxygen.
The distillation is generally carried out at an absolute pressure in the range from 5 to 25 bar and will determine the temperature at the head of the column required for the implementation of distillation.
Catalysts that can be used to effect the oxidation include catalysts based on transition metals, in particular catalysts based on cobalt and/or manganese and/or copper. Typically, they include catalysts based on copper or cobalt, such as cobalt coal used in the above methods for cleaning hydrocarbons from sulfur. Optionally, the catalyst contains other metals, such as compounds of alkali metals. As an example, one typical catalysts is a granular material sold by Johnson Matthey Catalyst as Johnson Matthey KSR, and contains 10-12% of the mass of copper sulfate, 6-8% of the mass of sodium chloride and 10-20% of the mass of water on the substrate of clay. He is active at the temperatures prevailing in the distillation column.
For maximizing the activity of the catalyst may be necessary to establish the water content in the raw materials to maintain the water content of the catalyst at its optimum value, or close to it, through the balance of the added water and the water produced in the reaction, with water removed in the faction, leaving the upper part of the column, and the liquid fraction. Typically, the amount of water that should be included in the initial hydrocarbon is such that it could be mixed with a stream of hydrocarbons under the prevailing conditions.
The catalyst preferably is located in the distillation column as a fixed layer. Can be used a column having a modular structure gaskets, with the catalyst loaded in the form of individual layers in each module.
The present invention is illustrated with reference to the accompanying drawing which is a block diagram of one of the embodiments of the present invention.
The drawing shows the column 10 fractional distillation of debutanizer used for separation of butane from a stream of liquid hydrocarbons from depropanizer. Thread 12 of liquid hydrocarbons is fed into the column in position, some distance up the column. Typically, the column may have 20 or more stages and, as a rule, at least one third, preferably at least half, but not more than three quarters of the steps will be following provisions, which serves the source material. At its lower edge column is supplied with a selection of 14 for the liquid. Part of the flow of liquid hydrocarbons are removed from the bottom of the column, agrawala in the reboiler 16 and recycled to the bottom of the column through line 18. The remaining part of the flow of fluid from the lower part of the column is the flow of gasoline.
On the top edge of the column 10, the steam flow from the head of the column containing butane, shown on line 20. These vapors are cooled in heat exchanger 22, which can be cooled with water or air for condensing steam, which is introduced into the drum 24. Part of the condensed liquid butane is recycled to the upper part of the column through line 26, and the remainder is withdrawn as stream 28 is received Bhutan. Located in the column, preferably above the input position of the hydrocarbons, is fixed layer 30 of the oxidation catalyst, such as Johnson Matthey KSR. Lines 32 and 34 are provided for injection of air and water, respectively, in the flow 12 of the original hydrocarbons.
The column operates at the same absolute pressure, as, for example, 10 bar, and the temperature of the steam in line 20 is in the range from 50 to 100°C. typically, the temperature of the fluid flow at the lower edge of the column is 20-60°C greater than that of the steam in line 20.
When you work a small amount of air and water is injected into the stream 12 of the original hydrocarbons. The number of injected air and water are such that they dissolve in the stream of hydrocarbons, thereby forming a single phase. In the column of the mercaptans in the original materials are oxidized under esteem catalyst, forming sulfur compounds with higher boiling points, which are separated as part of the flow of gas, leaving a grocery flow of butane, essentially not containing sulfur compounds.
As an example, the calculation of the flow of fluid from depropanizer has the following volumetric composition
It also contains 124 mlng methylmercaptan, 141 mlnd of ethyl mercaptan and 71 mlnd dimethyl sulfide (all mlnd by volume). The liquid stream is introduced at a rate of 70 KMOL/h (approximately 1,500 bbl/day) in debutanizer operating at an absolute pressure of 10 bar, at a reflux distilled 2, the head temperature of the column 70°C, the temperature of the lower part of the column 120°C and 20 degrees below the point of entry, and with 10 degrees above the insertion point. Air and water injections in the liquid source material at speeds of 0.022 KMOL/h and 0.025 KMOL/h, respectively 0.5 m3granules of catalyst Johnson Matthey KSR are in the form of a fixed layer in the column above the entrance plate.
According to calculations, the composition of the product is as shown forth in the following table. This table also indicates the calculated to the position, if the layer of catalyst and injection of water and air are excluded.
|The flow from the head of the column||Propane/butane||KMOL/h||43,2||43,2|
|The ethyl mercaptan||mind||8||0|
|The flow of gasoline||Butane/pentane||KMOL/h||26,8||26,8|
|The ethyl mercaptan||mind||356||125|
1. The method of separating a stream containing propane and/or butane, from the original hydrocarbons containing impurities of allylmercaptan by fractional distillation to obtain a liquid phase and separated flow from the head of the column, at such pressure that the separated flow from the head of the column containing the specified propane and/or butane, is at a temperature in the range from 50 to 100°S, including
(i) introduction to the specified original hydrocarbons in the amount of oxygen sufficient to oxidize the mercaptans in them,
(ii) carrying out fractional distillation of the mixture in the column containing at least one layer of a catalyst which oxidizes mercaptan to sulfur compounds with higher boiling points, and
(iii) separating sulfur compounds with more in the high boiling points as part of the liquid phase distillation.
2. The method according to claim 1, in which the catalyst contains a granular material containing a transition metal on a carrier.
3. The method according to claim 2, in which the transition metal includes copper, manganese or cobalt, or a mixture of two or more of them.
4. The method according to claim 3, in which the catalyst is a granular material containing copper sulphate, sodium chloride and water, the medium of clay.
5. The method according to any one of claims 1 to 4, in which the number of mercaptans present in the original hydrocarbons is less than 2000 mlnd volume.
6. The method according to any one of claims 1 to 4, in which the distillation is carried out at an absolute pressure in the range from 5 to 25 bar.
7. The method according to any one of claims 1 to 4, in which the oxygen is supplied by dissolving air in the original hydrocarbons.
8. The method according to any one of claims 1 to 4, in which water is included in the original hydrocarbons in such quantity that it is mixed with a stream of hydrocarbons.
FIELD: chemistry, organic.
SUBSTANCE: invention is related to a method for condensate stabilisation with production of solvent and kerosene-gas oil fraction comprising fractionating of raw stock and characterised in that the raw stock is fed to a heat exchanger wherefrom it is fed to a heater having live steam as a heat carrier, and then the raw stock heated to 140°C, at a pressure of 4 atm., is delivered to a hydraulic cyclone where the hydraulic cycloning process is carried out comprising creation of vacuum at the flow rotation centre, which results in a process of separation of light hydrocarbons that constitute the base of the solvent in the form of a vapour-gas mixture, the mixture being cooled in a condenser-cooler by water not higher than 15°C and collected in another tank in the form of solvent, dry gas from the mixture being supplied to a furnace while heavier hydrocarbons that are the base of the kerosene-gas oil fraction, in the form of separated liquid, are accumulated in a tank and fed to the heat exchanger at a temperature of 120°C, the heat exchanger performing heat transfer from hotter heavy hydrocarbons (the kerosene-gas oil fraction) to cold raw stock. A plant for realisation of the described method is also proposed. The method makes it possible to produce solvent and kerosene-gas-oil fraction in a single process and to simplify the design of the plant.
EFFECT: production of a solvent and a kerosene-gas oil fraction in a single process.
FIELD: petroleum processing.
SUBSTANCE: invention relates to rectification of petroleum feedstock and can be used in production of straight-run gasolines and gasoline components, e.g. iso- and normal pentanes. Process is implemented via separating feedstock into light, intermediate, and heavy fractions, one of which, after hydrofining and isomerization, is further rectified. Rectification column system comprises preliminary feedstock separation column and isomerizate separation column. Light fraction from preliminary column is recovered as commercial product and heavy fraction is sent to reforming. Intermediate fraction, which iC5-70°, is subjected to hydrofining and isomerization and then fed into isomerizate separation column to be separated into light fraction ΣC5, intermediate fraction, and heavy fraction ΣC6, light and heavy fractions being then used, respectively, as upper and lower recycles in preliminary column and intermediate fraction is recovered as commercial product. In other embodiments of invention, iC5 fraction from preliminary column is recovered as commercial product. In this case, recycle inlet points in preliminary column for light and heavy fractions are positioned, respectively, below and above outlet points for light and heavy fractions and, as upper and lower recycles of hexane column, respectively, ΣC5 and ΣC6 fractions are used. In addition, several heavy gasoline fractions are withdrawn from preliminary feedstock separation column through additional side outlets. In another embodiment of invention, iC5-70° fraction is withdrawn as intermediate fraction from preliminary separation column, subjected to hydrofining and isomerization and then introduced into isomerizate separation column, while light fraction from the same column is routed as recycle to preliminary column and heavy fraction is recovered as commercial product. Intermediate fraction from preliminary separation column is iC5-70° fraction, which is subjected to hydrofining and isomerization and then introduced into isomerizate separation column, while heavy fraction from the same column is routed as recycle to preliminary column and light fraction is recovered as commercial product.
EFFECT: increased rectification accuracy of gasoline fraction rectification and reduced energetic expenses.
11 cl, 3 dwg
FIELD: crude oil treatment.
SUBSTANCE: invention relates to removal of hydrogen sulfide and mercaptans from petroleum and gas condensate. Process is conducted through oxidation of impurities with air oxygen dissolved in petroleum under pressure up to 2.5 MPa at 20 to 70°C in presence of solution of ammonium salts of cobalt sulfophthalocyanines in 20-30% aqueous ammonia solution. Reagents are used in following amounts calculated per 1 mole hydrogen sulfide: 0.1-1.6 mole NH4OH, 0.05-0.1 g phthalocyanine catalyst, and 0.05-0.1 m3 air. More specifically, ammonium salts of cobalt sulfo-, disulfo-, tetrasulfo-, dichlorodisulfo-, and dichlorodioxydisulfophthalocyanine are used. Part of exhausted ammonia catalyst solution is separated from cleaned raw material and returned into process.
EFFECT: minimized consumption of reagents and power, and enabled carrying out the process directly under oil-field conditions.
10 cl, 1 dwg, 2 tbl, 3 ex
FIELD: crude oil treatment.
SUBSTANCE: to remove hydrogen sulfide and mercaptans, 3-30% solution of urotropin in technical-grade formalin or in formalin/aqueous ammonia is added to crude material in amounts corresponding to 0.8-3.5 mole formaldehyde and 0.009-0.3 mole urotropin per 1 mole hydrogen sulfide and mercaptan sulfur. Reaction is carried out at 15 to 70°C. Method is applicable for oil and gas production and petroleum processing industries.
EFFECT: reduced consumption of reagents at high degree of purification of raw material.
5 cl, 3 tbl