Method of removing mercaptans

 

Usage: petrochemistry. Essence: from naphtha wide range of boiling mercaptans and diolefine simultaneously removed in a distillation column type reactor for butane distillate fractions. The mercaptans react with diolefine with the formation of sulphides, which are more storable than4and a lighter part of naphtha, which selected the top shoulder straps. High-boiling sulfides are removed as a residue from the pickup together with C5and heavier materials. The remains of the pickup preferably served in a distant column, where part of the select top shoulder straps; and a more difficult part to remove the sulfides. This reduced the amount of naphtha can be hydrogensulfate to convert sulphides in H2S and diolefine that you can hydrogensulfate in olefins and alkanes. Technical result: a high degree of diatrypaceae. 10 C.p. f-crystals, 1 Il.

The present invention refers broadly to a method of removing mercaptans from flows of petroleum distillates. More specifically, the invention relates to a method where oil distillate contains diolefine that selectively react with the mercaptans to form sulfides. The most to fractional distillation to remove sulfides and, thus, the sulfur from distillate.

Flows of petroleum distillates contain a variety of organic chemical components. Usually, threads are characterized by their boiling ranges that define the composition. Processing flows also affects the composition. For example, products, processes or catalytic cracking or thermal cracking contain a high concentration of olefinic substances, as well as saturated compounds (alkanes) and polyunsaturated substances (diolefins). In addition, these components can be any of the various isomers of these compounds.

Petroleum distillates often contain undesirable impurities such as sulfur and nitrogen. These impurities often are catalytic poisons or lead to the formation of undesirable products during further processing. In particular, can cause anxiety sulfur compounds. Sulfur compounds are known catalyst poisons for catalysts for reforming of naphtha and hydrogenation catalysts. Present in the stream of sulfur compounds depend on the boiling range of the distillate. Mercaptans are usually found in low-boiling distillates, such as "head of the faction" naphtha wide range Anoy distillate is passed over a solid catalyst in the form of particles, comprising hydrogenating metal supported on a carrier of alumina. Raw materials include additional significant amounts of hydrogen. The following equations illustrate the reactions in a typical installation of HDS:

(1) RSH+H2RH+H2S

(2) RCl+H2RH+HCl

(3) 2RN+4H2RH+NH3

(4) ROOH+2H2RH+H2O

Typical working conditions for HDS reactions are:

Temperature,F 600-780

Pressure, psi wt. 600-3000

The rate of recirculation of H2,

STD.a cube.ft/bbl 1500-3000

Replenishment of fresh H2,

STD.a cube.ft/bbl 700-1000

As you can see, the emphasis is on the hydrogenation of sulfur and other polluting compounds. The sulfur is then removed in the form of gaseous H2S, which itself is a pollutant and requires further processing.

The flow of naphtha or from distillation column for refining or from fluid catalytic cracking installation usually fractionary several times in order to get useful fractions. Nafta wide boiling range (C4- 430F) beginning may podney column, then be depentanizer removal With5and lighter materials in the form of upper straps in pentanethiol column (sometimes referred to as the stabilization column), and finally divided into light naphtha (110-250VF) and heavy naphtha (250-430F).

U.S. patent No. 5510568 (Hearn) describes a method of removing mercaptans from distillate feedstock in the distillation column reactor type response contained in the raw material diolefines with the formation of sulfides in the presence of a catalyst comprising a metal of group VIII, and hydrogen. U.S. patent No. 5321163 (Hickey et al) describes a similar way to the esterification zone, also located in the distillation column reactor type. In both these processes distillate feedstock is served below the catalyst bed.

One of the advantages of the present invention is that the present method makes it possible to use existing butanother columns that have a higher pressure than the existing distant columns of petrol, thus providing the appropriate temperature in the layer of diatrypaceae that it is impossible to get in the running at low pressure outrun number is boiling, thus the mercaptans react in the whole range of petrol and achieved a deeper lieterature. Other advantages and features of the present invention will become apparent from the following description.

The present invention represents an improved method of removing mercaptans from a hydrocarbon stream crackerandoj naphtha wide range boiling point (C4- 430F) using a distillation column reactor type. Crakereanda nafta contains components from C4to C8that can be saturated (alkanes), unsaturated (olefins) and polyunsaturated (diolefin) together with minor quantities of mercaptans. Nafta wide range of boiling exposed debutanization in fractionation distillation column to remove the part that contains4and more low-boiling materials (C4-) as the upper shoulder straps and C5and more high-boiling materials (p5+) as the remains of the pickup. The present invention uses lower part butnothing columns for the reaction of substantially all of the mercaptans contained in crackerandoj nafta a wide range of boiling points, with a part of diolefines with education who may respond and be disposed in a layer of catalyst, located above the feed naphtha. Sulfides (including received in located above the layer) is removed in the form of residues from the pickup of butnothing columns with C5+ who served in the distillation column type pentanethiol where sulfides are removed with the remnants of the pickup6+ (or7+), a C5or (C5/S6) fraction having a reduced sulfur content, is removed as the top zipper. Sulfides in the residuals of the pickup can be hydrogensulfate in a separate distillation column type reactor or a fixed bed without distillation, to destroy sulfide, getting through this H2S and hydrologies diolefine. Separated from them H2S is not condensed.

Used for sulfide reaction catalyst is a supported on a carrier of aluminum oxide of the metal of group VIII, such as Nickel sulfide, for example, Nickel/molybdenum, which is typically configured in the form of patterns for catalytic distillation.

In sulfide reaction hydrogen is provided as a prerequisite to sustain the reaction and recovery of the oxide and maintain it in the hydride state.

The present method preferably operates at 200 pounds per square inch gage. and temperatures within the specified zone of the reactive distillation in the range from 100 to 400F, preferably from 130 to 270F. the Partial pressure of hydrogen is between 0.01 and 30 psi. Conditions for this separation accidentally meet the conditions for sulfide reaction. The selected pressure is such that maintains the temperature of the catalyst layer between 100 and 400F.

The term "reactive distillation" is sometimes also used to describe a parallel reaction and separation into fractions in the column. For the purposes of the present invention, the term "catalytic distillation" includes reactive rectification and any other way parallel reaction and fractional distillation in a column, despite applied for this designation.

The drawing is a simplified process flow diagram of an embodiment of the invention.

Description of the preferred embodiments in practice,

The present invention provides a method of response diolefins contained in the oil distillate, with the mercaptans contained in the distillate, with the formation of sulphides and in parallel over a high boiling point which contains the corresponding catalyst, for example in the form of patterns for catalytic distillation.

Raw materials for this installation is contained in one of the faction "naphtha wide range, which can include everything from4to C12and above. This mixture can easily contain from 150 to 200 components. Mixed flows of oil often contain a wide range of olefinic compounds. This is especially true for products obtained in the process either catalytic cracking or thermal cracking. The threads obtained in the refining, usually separated by fractional distillation and, because they often contain compounds with similar boiling points, such division is not exact. For example, C5the stream may contain fractions from C4to C12. These components can be saturated (alkanes), unsaturated (monoolefinic) or polyunsaturated (diolefin). In addition, the components can be any or all of the different isomers of individual compounds. Such streams typically contain from 15 to 30 wt.% isoamylenes.

These streams of oil also contain small amounts of sulfur compounds that must be removed. Sulfur compounds are usually found in the thread what about the selective hydrogenation of diolefins. Removal of sulfur compounds is usually called the demercaptanization of the stream.

Some minor components (diolefin) in raw materials will slowly react with oxygen during storage with the formation of tars and other undesirable substances. However, these components are also very responsive during TAME with the formation of yellow, unpleasant-smelling resinous substances and waste acid in the alkylation plant. Thus, it is obvious that the removal of these components is desirable regardless of whether you must use a fraction of the "light naphtha" only for the compounding of the gasoline, or as raw material for the process of TAME or alkylation.

Catalysts that are useful in the reaction of the mercaptan with diolefine include the metals of group VIII. Typically, the metals are precipitated as oxides on a carrier of alumina. Carriers are typically formed of particles or spheres with a small diameter. The catalyst must then be prepared in the form of a structure for catalytic distillation. Structure for catalytic distillation must be able to function as a catalyst and as a medium for mass transfer. The catalyst should be cooten. Accordingly, the catalyst contained in the structure described in U.S. patent No. 5730843, 5266546, 4731229 and 5073236 that are included in the description by reference.

A suitable catalyst for the reaction is 58 wt.% Ni on alumina with a size of 8 to 14 mesh, sold Calcicat and called E-475-SR. Typical physical and chemical properties of the catalyst, as it is offered by the manufacturer are as follows:

The rate of hydrogen in the reactor should be sufficient to maintain the reaction, but be kept below the rate which would have resulted in zachlapywaniu columns, which, as implied, constitutes "an effective amount of hydrogen" as that term is used here. Usually the molar ratio of hydrogen to diolefins and acetylenes in raw materials equal to at least a 1.0 to 1.0, preferably at least 2.0 to 1.0, and most preferably at least 10 to 1.0.

The catalyst also catalyzes the selective hydrogenation of the polyolefin contained in crackerandoj nafta, and, to a lesser extent, the isomerization of some monoolefins. Usually the relative reaction rates for the various compounds are in the order from faster to slower:

4) hydrogenation of monoolefins.

Interest reaction is the reaction of mercaptans with diolefine. In the presence of a catalyst mercaptans will also react with monoolefins. However, there is an excess of diolefins against the mercaptans in crakereanda ligroin raw materials and preferably mercaptans react with them to reaction with monoolefins. The equation of interest, the response is:

This can be compared with HDS reaction, which consumes hydrogen. Hydrogen consumed in the removal of mercaptans of the present invention, need this quantity, which is necessary to maintain the catalyst in the restored "hydride" state. If a parallel exists hydrogenation dienes, then hydrogen will be consumed in this reaction. For optimal processing residues from the pickup of the second column (distant columns) for the destruction of the sulfide with the formation of H2S and diolefines you should use at least a stoichiometric amount of hydrogen and preferably an excess of.

Typical compounds of mercaptans, which can be found in greater or lesser degree in �="https://img.russianpatents.com/chr/176.gif">F), n-propylmercaptan (TKip.154F), isopropylparaben (TKip.135-140F), isobutylparaben (TKip.190F), tert-butylmercaptan (TKip.147F), n-butylmercaptan (TKip.208F), ferrocilicate (TKip.203F), isoamylalcohol (TKip.250F), n-arylmercury (TKip.259F)-methylbutyrate (TKip.234F)-ethylpropylamine (TKip.293F), n-exillerating (TKip.304F), 2-mercaptohexyl (TKip.284F) and 3-mercaptohexyl (TKip.135F).

Typical diolefine in nafta full boiling range include BUTADIENES, isoprene (2-methylbutadiene-1,3), CIS - and TRANS-piperylene (CIS - and TRANS-1,3-pentadiene).

The present invention carries out the method in the column reactor filled with a solid catalyst, which contains the ascending vapour phase and a certain amount of the liquid phase as distillation. However, POSCO is the spine compared with a case when the liquid just goes down, so it would be normal internal irrigation.

Distillation column type reactor operates at a pressure such that the reaction mixture boils in the catalyst bed. Around the layer of catalyst by controlling the speed selection residues from the pickup and/or the upper straps can be maintained "foam level", which improves the efficiency of the catalyst, thereby reducing the height of the catalyst. As can be appreciated, the liquid boils and physical condition really is a foam having a higher density than would be normal in a distillation column filled with a catalyst, but less than the density of the liquid without boiling vapors.

The drawing shows a simplified flow diagram of one possible implementation of the invention. Crakereanda nafta (from C4to C7+) is served in the stabilization of the column in the form of a distillation column type reactor 10 through line 2 at a point above the catalyst layer 12. The hydrogen serves lower layer 12 through the pipeline 1. C5and heavier materials are selected in the top section of the distillation 15. C5and Baltoro for catalytic distillation. In the zone of the reactive distillation 12 essentially all of the mercaptans react with a part of diolefines with more high-boiling sulfides, which are distilled down and removed in the form of residues from the pickup through a pipe 8 with C5and heavier material. The rectification zone 16 is provided to ensure separation of sulphides.

With4and lighter distillate is less than the mercaptans (except mercaptan) are selected as the top straps through the pipe 5 and is passed through the condenser 13, where it is condensed condensable materials. The liquid collected in the tank 18, where gaseous substances, including unreacted hydrogen is separated and removed via line 3. Unreacted hydrogen can be sent to re-cycle (not shown), if desired. The liquid distillate product is removed through pipe 9. Some amount of liquid is directed to re-cycle in the column 10 in the form of phlegmy through the pipeline 6. A small layer to diatrypaceae 12’ may be placed above the pipeline to supply 2, where the mercaptan reacts with diolefine. The resulting thioether will Athanasia in the column together with the e for the installation of esterification, where contained isobutylene will turn into MTBE and unreacted normal butenes used in cold acid alkylation.

C5and heavier materials that contain sulfides, served by pipeline 8 to the second distillation column 20, which operates as a distant column. Thus the upper shoulder straps With6or C6/C7that does not contain sulfur and diolefine, you can remove without the need of dealing with all the raw material of the pipe 8 in the installation hydrogenation.

Column 20 operates to feed the upper wrap C5and a lighter fraction (C5- through pipe 25 to the condenser 23 where C5(and any other condensable substance, such as the remaining fraction4) is condensed and supplied to the tank 24. Not condensable substances go through the pipeline 27. Part of the condensed matter return to the column 20 in the form of phlegmy pipeline 26, and the remainder is removed in the form of essentially no sulfur-containing fractions With5.

The remains of the pickup 28 are6+ and contain sulfide compound. Residues from the evaporating device 28 can be hydrogensulfate hydrogen through the conduit 31 in the column 30, as a structure for distillation 32. Sulfides dissolved with the formation of H2S removed through pipe 34, and diolefines that you can gidrirovanii to olefins or alkanes, if there is a sufficient amount of hydrogen.

The upper shoulder straps 35 from the column 30 can be a C6+ faction with a part that is condensed in 33, accumulated in the reservoir 37 and returned as phlegm through pipe 36 and the stream removed through pipe 39. With7+ removed through pipe 38 in the form of essentially not containing sulfur and diolefine. The column could also work to choose the most part With6+ as the remains from the pickup just flow taken from the upper part of the column and returned in the form of phlegmy to control the system.

Hydrogenation residues from the pickup distant from the column 20 will not require such a large installation, as would be required if the processing of all raw materials from the pipe 8. There is no need to install hydrogenation represented a distillation column reactor type.

Example

In this example, in the lower part of the column with a diameter of one inch load 20 pounds of catalyst in the form of patterns for distillation. The upper section is left blank the>the contents of the mercaptan 285 wt.h/million

The content of diolefin about to 0.40 wt.%

The conditions and results are shown below.

Claims

1. Method of removing mercaptans from a hydrocarbon stream of naphtha range to a boil, using a distillation column reactor type, characterized in that it comprises the stage of:

(a) flow of naphtha wide boiling range containing mercaptans and diolefine, in the distillation column reactor of the above type catalyst containing deposited on the aluminum oxide of the metal of group VIII;

(b) feeding an effective amount of hydrogen in the specified distillation column type reactor below the catalyst bed;

(c) simultaneously in the specified distillation reactor column type exercise

(i) contact diolefins and mercaptans contained in the specified thread naphtha in the presence of hydrogen in the reaction zone of rectification, through this part of these mercaptans react with part of diolefines with the formation of sulfide products and

(ii) the separation of these sulfides from the specified distillate product by fractional distillation;

(d) the selection of the distillate of the second distillation, moreover, the specified distillate product has a low content of mercaptan; and (e) the selection of part of the hydrocarbon stream of naphtha and sulfide products from the specified distillation column type reactor at a point below the reaction zone of rectification.

2. The method according to p. 1, characterized in that the flow of naphtha wide range boiling is graciously ligroin distillate containing4and a lighter fraction and C5and a heavier fraction, and C4and the lighter fraction is removed as the top straps of the distillation reactor column type, and5and the heavier fraction is removed in the form of residues from the pickup from the specified distillation reactor column type with the specified sulfide product.

3. The method according to p. 1, wherein there is a molar excess of diolefins against the mercaptans.

4. The method according to p. 3, characterized in that essentially all of these mercaptans react with diolefine with the formation of sulfide products and a specified distillate product essentially free of mercaptans.

5. The method according to p. 3, characterized in that essentially all non-reacted with mercaptans excess diolefin is fty and sulfide products from stage (e) is separated into fractions with obtaining fractions of hydrocarbon naphtha, free from sulfide products, and the fraction of hydrocarbon naphtha, containing the sulfide products.

7. The method according to p. 1, characterized in that the fraction of hydrocarbon naphtha, containing the sulfide products, gidrogenit, getting H2S.

8. The method according to p. 1, characterized in that the second layer of catalyst containing deposited on the aluminum oxide of the metal of group VIII, include the above-mentioned flow of naphtha wide range of boiling points, where the mercaptan is in contact with diolefines and reacts with the formation of sulfide products.

9. The method according to p. 1, characterized in that the partial pressure of hydrogen is in the range from 0.1 to 30 psi.

10. The method according to p. 9, characterized in that the total pressure is 50-200 pounds per square inch gage.

11. The method according to p. 10, characterized in that the temperature in this zone of the reaction distillation is in the range from 100 to 400F.

 

Same patents:

The invention relates to oil fuel for gas turbines and more specifically to a method of obtaining fuel oil for gas turbines used for power generation gas turbine, to generate electricity using fuel oil for gas turbines and oil fuel for gas turbines

The invention relates to the refining, in particular to methods of Hydrotreating petroleum fractions

The invention relates to the field of oil refining, particularly to a method of Hydrotreating the oil distillers

The invention relates to methods of producing low-sulfur diesel by Hydrotreating of the feedstock and can be used in the refining industry

The invention relates to the refining of crude oil and, in particular, to the Hydrotreating of petroleum distillates

The invention relates to the refining of crude oil and, in particular, to the Hydrotreating of petroleum distillates

The invention relates to the refining and, specifically, to obtain jet fuel

The invention relates to the refining, in particular, to a method of cleaning gasoline thermal origin from unsaturated hydrocarbons and sulfur compounds for use as motor gasoline

The invention relates to methods for preparation of media and catalysts for refining and petrochemicals used in the processes for hydrogenation purification of heavy oil fractions, such as desalted crude oil, fuel oil, vacuum gas oil, oil shoulder straps, etc

The invention relates to the refining industry, in particular to methods for diesel fuel products from the direct distillation of crude oil

The invention relates to the refining, in particular to methods of Hydrotreating petroleum fractions
The invention relates to hydrogenation desulfurization of flow of oil in the distillation column reactor

The invention relates to the refining, in particular to a method of cleaning gasoline distillates secondary origin from sulfur and unsaturated compounds
Up!