RU61282U1 - INSTALLATION OF CLEANING OF HYDROCARBON RAW MATERIALS FROM SERO-ORGANIC COMPOUNDS - Google Patents

Abstract

The utility model relates to the purification of products of natural gas and gas condensate from organosulfur compounds and can be used in the gas processing industry. The technical result is the provision of the possibility of separation of dimethyl disulfides as an additional commercial product. The installation for purification of hydrocarbon feedstocks from organosulfur compounds contains a block for the demercaptanization of hydrocarbon feedstocks with an alkali solution with lines for supplying hydrocarbon feedstocks and the output of purified hydrocarbons and an alkaline solution saturated with mercaptides, an adsorption drying unit for purified hydrocarbons with a feed line for dried hydrocarbons, a regeneration unit for a saturated alkaline mercaptides solution with disulfide exit lines and regenerated alkali on the block of demercaptanization of hydrocarbons, and the additional but contains a disulfide fractionation unit, installed after the regeneration unit of the alkaline solution saturated with mercaptides, with dimethyl disulfide and bottoms outlet lines, including adsorbers connected through a pipe space of a recuperative heat exchanger to a distillation column, the top of which through an annular space of a recuperative heat exchanger, a refrigerator, and a reflux tank a dimethyl disulfide exit line, the latter being connected by an irrigation line to the top of the distillation tank the bosom, the bottom of which is connected through the second refrigerator and the second reflux tank with the output line of bottoms. [1 n. p. f., 1 Fig.]

Description

The utility model relates to the purification of products of natural gas and gas condensate from organosulfur compounds and can be used in the gas processing industry.

A known installation for the purification of hydrocarbons from mercaptans, hydrogen sulfide, carbon disulphide and carbon disulfide, described in the method of purification of hydrocarbons from mercaptans, hydrogen sulfide, carbon disulphide and carbon disulfide [RF Patent No. 2224006, 7MPK C 10 G 27/06, C 10 G 27/10, C 10 G 29/00, C 10 G 29/20, c. No. 2002120054, priority of 07.22.2002, publ. 02/20/2004 BI No. 5].

The installation includes a line for supplying hydrocarbon feed to the extractor, the top of which is connected through the separator to the outlet line of the purified feed, and the bottom through the heat exchanger, reactor, separator and settling tank is connected to the discharge line of disulfides, and the settling tank is connected through the pump to the top of the extractor. The reactor is connected at the bottom with an air supply line and is filled with activated carbon or carbon fiber material, the surface of which is coated with a phthalocyanine catalyst.

In the extractor during the interaction of hydrocarbon feedstock and an alkaline solution containing amine or alcohol additives, the feedstock is purified from hydrogen sulfide, mercaptans, carbon sulfide and carbon disulfide. Then the purified raw material enters the separator for sedimentation from the entrained alkaline solution, after which it is discharged from the installation along the outlet line. An aqueous solution of alkali from the bottom of the extractor is heated in a heat exchanger and enters the lower part of the reactor, where compressed air is also supplied. Sulfide oxidation occurs in the reactor.

to thiosulfate and sulfate, mercaptides, thiocarbomats and xanthates to the corresponding disulfides with alkali regeneration. Next, the alkaline solution in the separator is separated from the exhaust air, and enters the settling tank for sedimentation from disulfides, after which it is pumped to the upper part of the extractor, and disulfides are discharged from the installation along the outlet line.

In a known installation, disulfides are a waste of the process of purification of hydrocarbons from sulfur compounds.

Closest to the claimed purpose and the set of essential features is the installation of purification of the propane-butane fraction from organosulfur compounds, currently used at the Orenburg gas processing plant ["Technological regulations for the process of stabilization of condensate, purification of the propane-butane fraction from organosulfur compounds at U-330 ( Dep. 331, 335) of the third stage of the Orenburg Gas Processing Plant ”TR 2-23-02].

This installation for the purification of the propane-butane fraction (PBP) from organosulfur compounds contains a block for demercaptanization of PBP with an alkali solution, an adsorption drying unit for purified PBP, and a regeneration unit for the alkaline solution saturated with mercaptides.

The demercaptanization unit contains a hydrocarbon feed line, an alkali tank, three stages of alkaline purification of raw materials from organosulfur compounds, and a fourth step of washing the purified hydrocarbons from alkali with water, each of which includes a contactor-mixer, a separator and a circulation pump, a pump for feeding alkali to replenishment of three stages of purification, as well as the line of exit of the purified hydrocarbons to the adsorption drying unit, the line of exit of the alkaline solution saturated with mercaptides to the block egeneratsii water feed line for feeding the fourth stage and a conduit connecting the third and the second purification stage.

The adsorption drying unit of the purified PBF includes parallel mounted adsorbers filled with zeolite, the outlet line of the dried PBF, the supply and exhaust lines of the regeneration gas.

The regeneration unit of the alkaline solution saturated with mercaptides includes a regenerator column, a separation tank, a collection tank, lines for the regenerated alkali to exit to the demercaptanization unit and disulfides to the fractionation unit, air supply and exhaust lines, and a catalyst supply line.

Installation cleaning PBP from organosulfur compounds works as follows.

PBP is fed through the hydrocarbon feed line to the contactor-mixer, to mix with which the alkali from the first stage separator is fed by the circulation pump, and as a result of the reaction of hydrogen sulfide and carbon dioxide contained in the PBF, alkali removes hydrogen sulfide and carbon dioxide from the PBP, based on on the ability of organosulfur compounds (mercaptans, hydrogen sulfide, carbon dioxide) to react with alkali to form water-soluble and insoluble hydrocarbon compounds. The settled alkali, saturated with salts of sodium sulfide and sodium carbonate, is collected in the lower part of the separator, and PBP, purified from hydrogen sulfide and carbon dioxide, is sent to the second stage of purification.

PBF enters the second stage contactor-mixer, where alkali from the second stage separator is fed by a circulation pump to mix with PBF. When PBP is mixed with an alkali solution, the mercaptans contained in PBP and possessing slightly acidic properties react with alkali, resulting in the formation of mercaptides, which are practically insoluble in hydrocarbons. The settled alkali saturated with mercaptides is collected in the lower part of the separator, and the PBF partially purified from mercaptans is sent to the contactor-mixer of the third cleaning stage, where it is mixed with the PBF by a circulation pump

alkali is fed from the separator of the third stage. Part of this alkali stream is sent via a jumper to the second stage of purification. When PBP is mixed with an alkali solution, it is further purified from mercaptans to form mercaptides that saturate the alkaline solution. The settled alkali saturated with mercaptides is collected in the lower part of the separator of the third stage, and the PBF, purified from the mercaptans, is sent to the contactor-mixer of the fourth purification stage, where water is pumped from the separator of the fourth stage with a circulation pump, while the alkali contained in the PBF is dissolved in water. In the fourth stage separator, PBP is separated from water. Settled water is collected in the lower part of the separator, and PBP, purified from hydrogen sulfide, mercaptans and carbon dioxide, is sent to the adsorption drying unit.

PBP is fed to the adsorber operating in the adsorption mode for drying, and, passing from the bottom up through the adsorber, it is freed from water that is adsorbed on zeolites, and then the purified and dried PBF is sent to the freight fleet along the outlet line. In this case, the second adsorber operates in the zeolite regeneration mode. The adsorber is regenerated in the following sequence: emptying - regeneration - cooling - filling. The zeolite is regenerated by supplying a hot regeneration gas.

The alkali solution saturated with mercaptides from the second stage of purification of the demercaptanization unit is supplied with the Ivkaz catalyst and the mixture enters the regenerator column of the regeneration unit, into which cube technical air is supplied from the factory system. In the presence of a catalyst, mercaptides are oxidized by atmospheric oxygen to organic disulfides. Disulfides are insoluble in the catalytic alkaline solution and are separated from it by simple delamination. The regenerated alkali solution with disulfides is discharged from the upper part of the regenerator column to a separation tank, where disulfides are separated from the solution during delamination. The regenerated alkali solution is discharged with

bottom of the separation tank and is sent along the exit line to the demercaptanization unit for reuse. Disulfides (disulfide oil) are discharged from the top of the tank to a storage tank, from where they are sent to the stable condensate pipeline through the outlet line as a waste of the process of purifying PBP from organosulfur compounds.

When cleaning hydrocarbon feedstock (PBP) in a known installation, in the process of regeneration of a mercaptide alkaline solution, regenerated alkali and disulfides (disulfide oil) are obtained. The recovered alkali is then sent to the demercaptanization unit, and the disulfides recovered are waste products that are sent to the stable condensate line. Disulfides have the following composition,% mass .:

dimethyl disulfide 65-70 methyldisulfide 20-24 methyl isopropyl disulfide 0.04-0.05 diethyl disulfide 2-3 high boiling disulfides rest

As you can see, most of the composition falls on dimethyl disulfide, which is an expensive product and is in significant demand. Dimethyldisulfide is used as a sulfidizing agent of aluminum-cobalt-molybdenum and aluminum-nickel-molybdenum catalysts for the hydrotreatment of hydrocarbon condensate; as an inhibitor of coke formation during the pyrolysis of sulfur-free hydrocarbon feedstock in ethanol and liquefied petroleum gas pyrolysis plants; as a solvent of elemental sulfur. Dimethyldisulfide is not produced by the industry of the Russian Federation, and it has to be purchased abroad for the production needs of the domestic industry.

Thus, the disadvantage of the known installation is that the expensive product - dimethyl disulfide remains in the waste, which is not economically viable.

The inventive utility model solves the problem of expanding the technological capabilities of the installation for the purification of hydrocarbon raw materials from organosulfur compounds by providing the possibility of obtaining additional commercial product.

The task in the proposed installation for the purification of hydrocarbon raw materials from organosulfur compounds, containing a block for the demercaptanization of hydrocarbon raw materials with an alkali solution with lines for the supply of hydrocarbon raw materials and for the output of purified hydrocarbons and alkaline solution saturated with mercaptides, an adsorption drying unit for purified hydrocarbons with a line for dried hydrocarbons output, and a regeneration unit for saturated alkaline mercaptides solution with disulfide and regenerated alkali exit lines to the demercaptanization unit and hydrocarbon feedstocks, it is decided that it additionally contains a disulfide fractionation unit installed after the regeneration unit of the alkaline solution saturated with mercaptides, with dimethyl disulfide and bottoms outlet lines, including adsorbers connected through the pipe space of the recuperative heat exchanger to a distillation column, the top of which through the annulus a recuperative heat exchanger, a refrigerator and a reflux tank are connected to the dimethyl disulfide exit line, the last the line is connected by an irrigation line to the top of a distillation column, the bottom of which is connected through a second refrigerator and a second reflux tank to the bottom residue outlet line.

The technical result provided by the claimed installation is to provide the possibility of separation of dimethyldisulfides as an additional commercial product.

The difference between the proposed utility model and the one closest to the one indicated above is the presence of an additional disulfide fractionation unit installed after the saturated regeneration unit

mercaptides of alkaline solution, with the output lines of dimethyl disulfides and bottoms, including adsorbers connected through the pipe space of the recuperative heat exchanger with a distillation column, the top of which through the annular space of the recuperative heat exchanger, a refrigerator and reflux capacity is connected to the output line of dimethyl disulfides, the latter being connected to the top line distillation column, the bottom of which is connected through a second refrigerator and a second reflux tank with an exit line to bottom balance.

The presence of an additional block of fractionation of disulfides in the proposed installation allows for the purification of hydrocarbon raw materials from organosulfur compounds by distillation of disulfides in a distillation column, followed by cooling in a recuperative heat exchanger and refrigerator, to additionally isolate dimethyl disulfides.

Thus, a new set of essential features in the proposed installation allows you to expand its technological capabilities by obtaining an additional commercial product - dimethyl disulfides.

The drawing shows a diagram of a plant for the purification of hydrocarbon from organosulfur compounds.

The installation for the purification of hydrocarbon feed from organosulfur compounds consists of the following blocks:

- block I of demercaptanization of hydrocarbons, including a line 1 for the supply of hydrocarbons, a tank 2 with alkali, sequentially installed three stages of alkaline cleaning of raw materials from organosulfur compounds and the fourth stage of washing purified hydrocarbons with water from alkali, each of which includes a contactor-mixer 3-6, separator 7-10 and circulation pump 11-14, alkali supply pump 15 to feed the three stages of cleaning, and also the exit line 16

purified hydrocarbons to block II of adsorption drying, line 17 of the outlet of the alkaline solution saturated with mercaptides to block III of regeneration, line 18 of water supply to feed the fourth stage and a jumper 19 connecting the third and second stages of purification;

- block II adsorption drying of purified hydrocarbons, including adsorbers 20-21 filled with zeolite, a line 22 of the exit of the dried hydrocarbons, the supply line 23 and the exhaust 24 of the regeneration gas;

- block III regeneration of alkaline solution saturated with mercaptides, including regenerator column 25, separation tank 26, collection tank 27, regenerated alkali outlet line 28 to demercaptanization unit I, disulfide outlet line 29 to fractionation unit IV, supply line 30 and air exhaust 31 catalyst supply line 32;

- block IV of disulfide fractionation, installed after block III of regeneration of alkaline solution saturated with mercaptides and including two-layer filling adsorbers 33-34 installed in parallel, recuperative heat exchanger 35, distillation column 36, refrigerators 37-38, reflux tanks 39-40, reboiler 41, lines 42 and 43 of the output of bottoms and dimethyl disulfides, the latter being connected by an irrigation line 44 to the top of a distillation column 36, a supply line 45 and a fuel gas outlet 46 for regenerating adsorbers 33-34, which line 47 is connected through the pipe space of the recuperative heat exchanger 35 to the distillation column 36. The top of the distillation column 36 through the annular space of the recuperative heat exchanger 35, the cooler 37 and the reflux tank 39 is connected to the dimethyl disulfide exit line 43. The bottom of the column 36 is connected through a refrigerator 38 and a reflux tank 40 to the bottoms outlet line 42. Adsorbers 33-34 are filled with silica gel and activated carbon.

Installation works as follows.

Hydrocarbon feedstock through line 1 enters the contactor-mixer 3 of the first stage, where, when mixed with alkali supplied by the pump 11 from the bottom of the separator 7, the reaction of the combination of hydrogen sulfide and carbon dioxide with alkali in the feed occurs with the formation of water-soluble and insoluble in hydrocarbons compounds. The resulting mixture enters the separator 7 for the separation of hydrocarbons and alkali. After interaction with hydrogen sulfide and carbon dioxide, the alkali is collected in the lower part of the separator 7, and the hydrocarbons purified from carbon dioxide and hydrogen sulfide are sent to the contactor-mixer 4 of the second stage, to which alkali is fed from the lower part of the separator 8 by the pump 12. When hydrocarbons are mixed with an alkali solution, the mercaptans contained in the hydrocarbon feed react with the alkali to form mercaptides. At the second stage, the main purification of hydrocarbons from mercaptans takes place. In separator 8, an alkali saturated with mercaptides is collected in the lower part, and hydrocarbons partially purified from mercaptans are sent to the contactor-mixer 5 of the third purification stage. At the same time, from the bottom of the separator 9, the alkali is pumped 13 by one flow to the mixing contactor-mixer 5, and by the other stream through the jumper 19 to the second cleaning stage. At the third stage, hydrocarbons from mercaptans are treated in a similar way. The alkaline solution saturated with mercaptides is collected in the lower part of the separator 9, and the hydrocarbons purified from the organosulfur compounds are sent to the fourth stage contactor-mixer. Water is mixed with hydrocarbons by a pump 14 to wash them from alkali from the bottom of the separator 10, as a result of which the alkali dissolves in water. In the separator 10, due to the difference in specific gravities, hydrocarbons and water are separated. The loss of water in the fourth stage, carried along with hydrocarbons to the drying unit II, is replenished from line 18.

The purified hydrocarbons from the separator 10 through the exit line 16 are sent to the adsorber 20 operating in the adsorption mode. Passing from the bottom up through the adsorber 20, the hydrocarbons are freed from the water that is adsorbed on the zeolites, after which the dried hydrocarbons are discharged through line 22 to the goods park. In this case, the adsorber 21 operates in the mode of regeneration of the zeolite. The adsorber is regenerated in the following sequence: emptying - regeneration - cooling - filling. Zeolite is regenerated by supplying hot regeneration gas through line 23 to adsorber 21, which, passing from the bottom up, takes moisture and is discharged through line 24.

The alkaline solution saturated with mercaptides from the second stage of block I of the demercaptanization line 17 along with the Ivkaz catalyst supplied via line 32 enters the regeneration column 25 of the regeneration block III, into which a cube of technical air is supplied through line 30. In the presence of a catalyst, mercaptides are oxidized by atmospheric oxygen to organic disulfides.

2RSNa + ½O ₂ + H ₂ O → RSS-R + 2NaOH.

Disulfides are insoluble in the catalytic alkaline solution and are separated from it by simple delamination. The regenerated alkali solution with disulfides is discharged from the regenerator column 25 to a separation vessel 26, where the separation of disulfides and alkali takes place. The regenerated alkali solution is discharged from the bottom of the separation tank 26 and is sent through line 28 to the tank 2 to the demercaptanization unit I for reuse. Disulfides from the top of the tank 26 enter the collection tank 27, from where they are sent via line 29 to the adsorber 33 of fractionation unit IV. In the adsorber 33 operating in the adsorption mode, when the disulfides pass from the bottom up, they are dried with silica gel, and when the activated carbon layer passes, the disulfides are purified from the catalyst. Dried and purified from the catalyst disulfides from the adsorber 33 are sent along

line 47 for heating into the pipe space of the recuperative heat exchanger 35. The disulfides heated to a temperature of not more than 60 ° C then enter the distillation column 36, the top temperature of which is not more than 105 ° C, and the cube temperature is maintained by reboiler 41 no more than 120 ° C.

In the distillation column 36, dimethyldisulfides (DMDS) are supplied as an irrigation liquid via line 44. In the distillation column 36, upon repeated contact of the liquid and vapor phases, disulfides are separated. In this case, boiling dimethyldisulfides accumulate in the vapor phase, and heavier ones (methyldisulfides, methylisopropyl disulfides, etc.) are deposited in the cube of the column 36. The vapor phase of dimethyldisulfides from the top of the column 36 is cooled to the annular space of the recuperative heat exchanger to 35 °, where it is cooled C, heating the tube space through which disulfides from the adsorber 33 are supplied. From the heat exchanger 35, the DMDS enters further cooling and condensation in the refrigerator 37, and then enters the reflux tank 39, from on line 43 in the form of a commercial product are output from the installation. At the same time, part of the DMDS through line 44 is sent to the column 36 to be irrigated. The bottoms product (heavy disulfides) from the distillation column 36 is fed to the cooler 38 for cooling and condensation, then to the reflux tank 40, from which it is withdrawn from the unit as line waste.

In this case, the adsorber 34 operates in the regeneration mode of the adsorbent. The regeneration is carried out by fuel gas from line 45 passing through the adsorber 34 from the bottom up and is discharged along line 46. The adsorbers 33 and 34 operate alternately.

Thus, the use of the proposed installation for the purification of hydrocarbon raw materials from organosulfur compounds allows for the provision of the possibility of separation of expensive dimethyl disulfides from disulfides, which are a waste of the hydrocarbon purification process

raw materials, get an additional commercial product, which greatly expands the technological capabilities of the installation and increases the efficiency of the process. In addition, the problems of domestic product production and reduction of imports of dimethyl disulfide are being addressed.

Claims (1)

Installation for cleaning hydrocarbon feedstocks from organosulfur compounds, containing a block for the demercaptanization of hydrocarbon feedstocks with an alkali solution with supply lines for hydrocarbon feedstocks and the yield of purified hydrocarbons and alkaline solution saturated with mercaptides, an adsorption drying unit for refined hydrocarbons with a dried hydrocarbons outlet line, a regeneration unit for alkaline solution saturated with mercaptides with outlet lines disulfides and regenerated alkali on the block of demercaptanization of hydrocarbons, which distinguishes The fact that it additionally contains a disulfide fractionation unit installed after the regeneration unit of the alkaline solution saturated with mercaptides with dimethyl disulfide and bottoms outlet lines, including adsorbers connected through a pipe space of a recuperative heat exchanger to a distillation column, the top of which through the annular space of a recuperative heat exchanger, a refrigerator and the reflux capacity is connected to the dimethyl disulfide exit line, the latter being connected to the irrigation line with erhom distillation column, the bottom of which is connected through a second reflux refrigerator and a second capacitance from the output line of the distillation residue.