RU2764595C1 - Unit and method for purifying gaseous hydrocarbon raw materials from hydrogen sulphide and mercaptans - Google Patents

Abstract

FIELD: gas purification.

SUBSTANCE: invention relates to a unit for purifying gaseous hydrocarbons from hydrogen sulphide and mercaptans, containing a desulfurisation reactor 6 filled with a solution of a catalyst for oxidation of hydrogen sulphide and mercaptans into sulphur and disulphides, respectively, in an organic solvent, an apparatus for discharging the sulphur solution from the reactor into the sulphur separation unit, and a sulphur separation unit, wherein the unit comprises at least a means of supplying the purified gaseous hydrocarbons and oxygen-containing gas into the reactor, a means of discharging the purified gas from the reactor, and the separation unit comprises a means of sulphur extraction, wherein a disk film reactor with means of distributing the mixture of hydrocarbon and oxygen-containing gas throughout the volume of the reactor is used as a desulphurisation reactor, the unit additionally comprises a container with a catalyst solution, wherein connected to the first input of the reactor via the mixer for the purified hydrocarbon gas with the oxygen-containing gas are the pipeline for supplying gaseous hydrocarbon raw materials for purification and the pipeline for supplying an oxygen-containing gas, installed whereon is an oxygen-containing gas flow rate agitator, a container with the catalyst solution, by means of the agitator for supplying the catalyst solution from the container into the reactor and the pipeline for supplying the catalyst solution into the reactor, is connected to the second input of the reactor, the first output of the reactor is connected to the purified hydrocarbon gas removal pipeline, the second output of the reactor is connected to the pipeline for discharging the sulphur suspension into the sulphur separation unit, the first output of said separation unit is connected to the sulphur discharge pipeline, the second output of said separation unit is connected to the pipeline for discharging the catalyst solution from the block, wherein said pipeline, through the catalyst solution recycling agitator, is connected to the third input of the reactor.

EFFECT: ensured purification of gaseous hydrocarbons.

5 cl, 2 dwg, 6 ex

Description

The invention relates to the field of gas purification from impurities of sulfur-containing ecotoxicants, hydrogen sulfide H ₂ S, mercaptans, RSH R=C _n H _2n+1 , n=1-12. These compounds are among the most aggressive and toxic impurities of hydrocarbons, natural and associated petroleum gas (APG). Because of this, the content of hydrogen sulfide and mercaptans is regulated by GOST, STO, production regulations at the level of hundredths and thousandths of a percent.

Known (RU, patent 2157722, publ. 20.10.2000) method of gas purification and drying and device for its implementation and dried gas at low pressure, and increasing the gas pressure in the adsorber to the operating value after regeneration, while the purge gas is divided into hot and cold flows in the vortex tube when the pressure is reduced, the adsorbent is blown with the hot stream, the pressure in the adsorber is reduced below the purge pressure, and the products are pumped out purification, increase the pressure to the purge value, which is carried out with a cold stream at a temperature below the temperature of the gas to be purified, and a gas purification and drying device containing adsorbers, for example, with a mixed adsorbent, connected to the supply manifold of the purified gas and to the exhaust manifold of the purified and dried gas , receiver, mouth upgraded to the latter, a purge gas vent header, provided with a vortex tube, an ejector installed after the receiver, and a heat exchanger installed between the receiver and the vortex tube and on the purge gas vent header

The disadvantages of the invention are:

- low efficiency of short-cycle non-heating adsorption in the processes of purification and drying of natural gas with a low concentration of extractable impurities (1-2%), since this method is inherently designed to extract components from a mixture with a high concentration of impurities, for example, the extraction of oxygen from air, hydrogen from synthesis gas, etc.;

- the presence of a vortex tube to increase the temperature of the purge gas, which practically does not affect the quality of desorption, since, firstly, during a short desorption time, the adsorbent can heat up only by 10-15°C, and secondly, even at the temperature of the purge gas at the outlet from a vortex tube of 81.5°C, the adsorbent at atmospheric pressure is capable of adsorbing a significant amount of impurities, that is, the regeneration process will hardly improve;

- the problem of the use or disposal of desorption products.

Known (RU, patent 2573677, published on January 27, 2016) is a method and device for removing contaminants from a gas stream. The known method includes:

(a) introducing a gas stream into the reaction chamber of the gas scrubbing column;

(b) introducing reactive elements in the liquid phase into the collector of the gas scrubbing column and oxidizing the first contaminants in said liquid phase;

(c) obtaining an oxidizing solution from said oxidation in step (b);

(d) oxidizing the second contaminants in the gas phase of the gas stream above the reservoir, separating excess reactive elements from the oxidizing solution in the reservoir;

(e) oxidation and washing out of third contaminants in the gas-liquid contact device located above the gas stream; and stages (b)-(e) are carried out simultaneously.

A known device for removing contaminants from a gas stream contains:

a container with a reaction chamber inside it to receive the gas stream;

a gas-liquid contact device located in the reaction chamber;

a collection located in the reaction chamber under the device gas-liquid contact, while the collection is made to receive and contain the liquid washing reagent;

a first inlet in communication with the reservoir for supplying reactive elements to the liquid washing agent contained in the reservoir to obtain an oxidizing solution;

a second inlet in communication with the reaction chamber for supplying a gas flow to the reaction chamber between the gas-liquid contact device and the collector;

and a supply conduit, the first end of which communicates with the collector, and the second end has an outlet opening in the reaction chamber above the gas-liquid contact device to distribute the oxidizing solution to ensure its contact with the gas-liquid contact device.

The disadvantage of the known technical solution should be recognized as its low efficiency.

Known (RU, patent 2394635, publ. 20.07.2010) method of purification of gases from hydrogen sulfide, mercaptans and other sulfur-containing compounds, carbon dioxide and other acidic impurities by the absorption method using a solution of medium sodium salt and sodium hydroxide as absorbents. Purified gases under high pressure are successively treated with two absorbents, first with an aqueous solution of medium sodium salts of hydrogen sulfide and carbonic acids, and then with an aqueous solution of sodium hydroxide.

Also known (ibid) is a plant for cleaning gases from hydrogen sulfide, mercaptans and other sulfur-containing compounds, carbon dioxide and other acidic impurities, including two absorbers, each of which is equipped with a supply tank for the absorbent and a pump for metered supply of the absorbent to the absorber, and in the second in the course of the purified gas, the absorber circulates a solution of sodium hydroxide, as well as collectors of waste absorbents. The absorbers are connected in series, operate under pressure, the second absorber is equipped with a circulation pump.

The collection of the first absorber is connected to a pressure pump that serves to pump the spent absorbent into isolated reservoirs for disposal. At the same time, water and spent absorbent from the second absorber are used as an absorbent in the first absorber, additionally, the installation contains a compressor for creating a given pressure of the purified gas and a separator connected to it, which serves to separate gas condensate and water.

The disadvantages of the known technical solution should be recognized as the low quality of cleaning, high consumption of alkali, obtaining a large amount of toxic waste that is difficult to dispose of.

Known (RU, patent 2398735, publ. 10.09.2010) method of purification of gas streams from hydrogen sulfide by oxidation of hydrogen sulfide to elemental sulfur in the liquid phase in the presence of a catalyst containing a transition metal compound and an organic complexing substance. It is proposed to use oxygen for the oxidation of hydrogen sulfide, copper halide is used as a transition metal compound, the copper content in the solution is from 0.015 to 0.1 wt. %, and as an organic complexing substance, a compound selected from dimethylformamide, pyrrolidone, methylpyrrolidone, pyridine or quinoline, the process is carried out in a solvent medium selected from the following: monohydric alcohol, polyhydric alcohol, water or mixtures thereof, kerosene, isooctane, gas condensate, at a temperature of 20-40°C.

The disadvantage of the known method should be recognized as its low efficiency.

The closest analogue of the developed technical solution can be recognized (RU, patent 2649442, publ. 04/03/2018) device and method for one-stage purification of gaseous hydrocarbon feedstock simultaneously from hydrogen sulfide and mercaptans.

A well-known installation for single-stage purification of gaseous hydrocarbon feedstock simultaneously from hydrogen sulfide and mercaptans contains a catalytic reactor filled with a solution of a catalyst for the oxidation of hydrogen sulfide and mercaptans to sulfur and disulfides, respectively, in an organic solvent, a device for removing sulfur solution from the reactor to a sulfur separation unit and a sulfur separation unit, while the installation contains, at least, means for feeding gaseous hydrocarbon feedstock to be treated and oxygen-containing gas into the reactor, means for removing purified gas from the reactor, and the sulfur separation unit contains means for separating sulfur, and the design of the installation and the composition of the catalyst provide a conversion of at least 99.99 % hydrogen sulfide and mercaptans into sulfur and disulfides, and the catalyst is a mixed ligand complexes of transition metals.

A method for one-stage purification of gaseous hydrocarbon feedstock simultaneously from hydrogen sulfide and mercaptans, characterized in that the gaseous hydrocarbon feedstock to be purified in a mixture with an oxygen-containing gas is passed through a reactor with an organic solution of a catalyst that ensures the conversion of hydrogen sulfide and mercaptans by at least 99.99% to sulfur and disulfides, while the catalyst is a mixed ligand complexes of transition metals.

The disadvantages of the known technical solution should recognize the large volume of the desulphurization reactor required for the quantitative conversion of hydrogen sulfide and mercaptans into sulfur and disulfides, respectively.

The technical problem solved by the present invention is to improve the technology of purification of gaseous hydrocarbons from hydrogen sulfide and mercaptans.

The technical result obtained by implementing the developed technical solution is to increase the efficiency of purification of gaseous hydrocarbons from hydrogen sulfide and mercaptans while reducing the volume of the installation.

To achieve this technical result, it is proposed to use the developed device and method for purifying gaseous hydrocarbons from hydrogen sulfide and mercaptans.

The plant of the developed design contains a disk film desulphurization reactor with means for distributing a mixture of hydrocarbon and oxygen-containing gas throughout the reactor volume, a sulfur separation unit and a container with a catalyst solution, while the first inlet of the reactor is connected, through a mixer of the purified hydrocarbon gas with oxygen-containing gas, to a pipeline for supplying gaseous hydrocarbon raw materials for purification and an oxygen-containing gas supply pipeline, on which an oxygen-containing gas flow booster is installed, a container with a catalyst solution is connected to the second reactor inlet by means of a catalyst solution feed booster from the container to the reactor and a catalyst solution supply pipeline to the reactor, the first reactor outlet is connected to the outlet pipeline purified hydrocarbon gas, a pipeline for withdrawing sulfur suspension to the sulfur separation unit is connected to the second outlet of the reactor, the first outlet of the specified separation unit is connected to the sulfur removal pipeline, the second The second outlet of said separation unit is connected to a catalyst solution outlet pipeline, said pipeline being connected to the third inlet to the reactor via a catalyst solution recycle booster.

In some embodiments of the developed plant, an air compressor can be used as an oxygen-containing gas flow booster, a dosing pump can be used as a booster for the catalyst solution supply from the tank, and a pump can be used as a catalyst solution recycle booster from the sulfur separation unit.

According to the developed method for purifying gaseous hydrocarbon feedstock from hydrogen sulfide and mercaptans, a non-aqueous organic solvent and a catalyst are loaded into the desulphurization reactor, a mixture of the gas to be purified and oxygen-containing gas is fed to the reactor inlet through the mixer, after contact of the supplied gas mixture with the catalyst solution, finely dispersed sulfur is released to form a suspension sulfur in the catalyst solution, the suspension of sulfur in the catalyst solution enters the sulfur separation unit, where sulfur is separated from the catalyst solution, then the catalyst solution is returned to the reactor.

In the future, the essence and advantages of the developed technical solution will be considered using examples of implementation.

The scheme for implementing the process in the installation and according to the method that make up the developed technical solution differs from the closest analogue in the design of the desulfurization reactor.

The developed installation and method provide for the use of a disk film apparatus as a desulfurization reactor.

In FIG. 1 shows a block diagram of the developed installation in the preferred embodiment, the following designations are used: pipeline 1 for supplying raw materials for purification, mixer 2 for hydrocarbon gas to be purified with oxygen-containing gas, pipeline 3 for supplying oxygen-containing gas, booster 4 for the flow of oxygen-containing gas, pipeline 5 for supplying the mixture purified hydrocarbon gas with oxygen-containing gas, desulphurization reactor 6, means 7 for distributing a mixture of hydrocarbon and oxygen-containing gas throughout the volume of reactor 6, container 8 with a catalyst solution, stimulator 9 for supplying a catalyst solution from container 8 to reactor 6, pipeline 10 for supplying a catalyst solution to reactor 6 , pipeline 11 for removal of purified gas, pipeline 12 for sulfur suspension output to sulfur separation unit 13, pipeline 14 for sulfur output from separation unit 13, pipeline 15 for catalyst solution output from separation unit 13 to reactor 6 after sulfur separation, catalyst solution recycle booster 16 from sulfur separation unit 13 to reactor 6.

In FIG. 2 shows the main stages of the implementation of the method, with the following designations used: supply of the purified gaseous hydrocarbon feedstock mixed with oxygen-containing gas to the inlet of the reactor 17, passing the purified feedstock through the reactor with an organic solution of the catalyst 18, obtaining pure gas at the reactor outlet, and the conversion of hydrogen sulfide and mercaptans into sulfur and disulfides is 99.99% 19, the use of an amount of oxygen of at least 50% of the total content of hydrogen sulfide and mercaptan sulfur 20, the distribution of the gas mixture evenly over the volume of the reactor 21, the dosed supply of the catalyst to the reactor 22, the separation of sulfur from the suspension and recycle of the catalyst solution to the reactor 23, maintaining the temperature in the installation within 25-140°C 24.

In the future, the essence of the gas desulfurization method in a disk film apparatus and the advantages of the developed technical solution will be considered using implementation examples.

Example 1. Gas purification according to the patent RU, 2649442 RF. A non-aqueous organic solvent and a catalyst according to patent RU, 2649442 are loaded into the bubbling-type desulphurization reactor. The volume of the solution is 500 ml. A gas stream containing 0.1% vol. hydrogen sulfide, 0.05% mercaptan sulfur and 0.06% vol. enters the reactor inlet. oxygen. Solution temperature 25°C. At the outlet of the reactor, according to potentiometric titration, the content of hydrogen sulfide and mercaptans in the gas is 120 and 100 ppm, respectively. The conversion of hydrogen sulfide and mercaptans is 88 and 80%, respectively.

Example 2. Gas purification according to patent RU, 2649442.

A non-aqueous organic solvent and a catalyst according to patent RU 2649442 are loaded into the bubbling-type desulphurization reactor. The volume of the solution is 1000 ml. A gas stream containing 0.1% vol. hydrogen sulfide, 0.05% mercaptan sulfur and 0.06% vol. enters the reactor inlet. oxygen. Solution temperature 25°C. At the outlet of the reactor, according to potentiometric titration, the content of hydrogen sulfide and mercaptans in the gas is 60 and 50 ppm, respectively. The conversion of hydrogen sulfide and mercaptans is 94 and 90%, respectively.

Example 3. Gas purification according to patent RU, 2649442.

A non-aqueous organic solvent and a catalyst according to patent RU, 2649442 are loaded into the bubbling-type desulphurization reactor. The volume of the solution is 2000 ml. A gas stream containing 0.1% vol. hydrogen sulfide, 0.05% mercaptan sulfur and 0.06% vol. enters the reactor inlet. oxygen. Solution temperature 25°C. At the outlet of the reactor, according to the data of potentiometric titration, the content of hydrogen sulfide and mercaptans in the gas is 5 and 10 ppm, respectively. The conversion of hydrogen sulfide and mercaptans is 99.5 and 98%, respectively.

Example 4. Gas purification according to the patent RU, 2649442 RF. A non-aqueous organic solvent and a catalyst according to patent RU, 2649442 are loaded into the bubbling-type desulphurization reactor. The volume of the solution is 100 ml. A gas stream containing 0.05% vol. hydrogen sulfide, 0.02% mercaptan sulfur and 0.06% vol. enters the reactor inlet. oxygen. Solution temperature 25°C. At the outlet of the reactor, according to the data of potentiometric titration, the content of hydrogen sulfide and mercaptans in the gas is 260 and 150 ppm, respectively. The conversion of hydrogen sulfide and mercaptans is 48 and 25%, respectively.

Thus, to ensure desulphurization in the installation and according to the method of patent RU, 2649442 RF, at least 2 liters of catalyst solution and, as a consequence, the volume of the desulfurization reactor are required. With a decrease in the volume of the absorber with a load of 1000 ml, 500 ml and 100 ml of the solution, the implementation of the known method does not ensure the achievement of the technical result in the conversion of SH>99.99%. In a solution volume of 100 ml, it is possible to remove only 48 and 25% of hydrogen sulfide and mercaptans, respectively, even with a decrease in the concentration of hydrogen sulfide and mercaptans at the inlet.

As shown in the examples below, the developed technical solution ensures the conversion of hydrogen sulfide and mercaptans SH>99.99% with a significant reduction in equipment volume. This result is achieved by switching from using a known plant design to a developed plant design, as follows from the examples of the invention below.

Example 5 Purification of the gas according to the present invention.

A non-aqueous organic solvent and a catalyst according to patent RU, 2649442 are loaded into the disk film reactor of the desulfurization unit. The volume of the solution is 100 ml. A gas stream containing 0.1% vol. hydrogen sulfide, 0.05% mercaptan sulfur and 0.06% vol. enters the reactor inlet. oxygen. Solution temperature 25°C. At the outlet of the reactor, according to potentiometric titration, the content of hydrogen sulfide and mercaptans in the gas is 10 and 30 ppm, respectively. The conversion of hydrogen sulfide and mercaptans is 99 and 94%, respectively.

Example 6 Purification of the gas according to the present invention.

A non-aqueous organic solvent and a catalyst according to patent RU, 2649442 are loaded into the disk film reactor of the desulfurization unit. The volume of the solution is 150 ml. A gas stream containing 0.1% vol. hydrogen sulfide, 0.05% mercaptan sulfur and 0.06% vol. enters the reactor inlet. oxygen. Solution temperature 25°C. At the outlet of the reactor, according to potentiometric titration, the content of hydrogen sulfide and mercaptans in the gas is 8 and 10 ppm, respectively. The conversion of hydrogen sulfide and mercaptans is 99.2 and 98%, respectively.

Thus, the design of the installation according to the present invention provides desulfurization to a residual SH content of 10 ppm in a solution volume of 150 ml. This volume is an order of magnitude less than during desulfurization in a bubbling type reactor according to patent RU, 2649442.

Claims (5)

1. Installation for the purification of gaseous hydrocarbon feedstock from hydrogen sulfide and mercaptans, containing a desulphurization reactor 6 filled with a solution of a catalyst for the oxidation of hydrogen sulfide and mercaptans into sulfur and disulfides, respectively, in an organic solvent, a device for removing sulfur solution from the reactor to a sulfur separation unit, and a sulfur separation unit , while the plant contains at least means for supplying gaseous hydrocarbons and oxygen-containing gas to be purified into the reactor, a means for removing purified gas from the reactor, and the sulfur separation unit contains a means for separating sulfur, characterized in that a disk film reactor with by means of distributing a mixture of hydrocarbon and oxygen-containing gas throughout the volume of the reactor, the installation additionally contains a container with a catalyst solution, while the first inlet of the reactor is connected, through a mixer of the purified hydrocarbon gas with oxygen-containing gas, to a pipeline for supplying gaseous hydrocarbon feedstock for purification and the oxygen-containing gas supply pipeline, on which the oxygen-containing gas flow booster is installed, the container with the catalyst solution is connected to the second reactor inlet by means of the catalyst solution feed booster from the container to the reactor and the catalyst solution supply pipeline to the reactor, the first reactor outlet is connected to the pipeline removal of purified hydrocarbon gas, a pipeline for withdrawing sulfur suspension to the sulfur separation unit is connected to the second outlet of the reactor, the first outlet of the specified separation unit is connected to the sulfur outlet pipeline, the second outlet of the specified separation unit is connected to the pipeline for the output of the catalyst solution from the unit, and the specified pipeline through the recycle booster catalyst solution is connected to the third inlet to the reactor. 2. Installation according to claim 1, characterized in that an air compressor is used as an oxygen-containing gas flow stimulator. 3. Installation according to claim. 1, characterized in that a dosing pump is used as a stimulator for supplying a catalyst solution from a container. 4. Installation according to claim 1, characterized in that a pump is used as a catalyst solution recycle stimulator from the sulfur separation unit. 5. A method for purifying gaseous hydrocarbon feedstock from hydrogen sulfide and mercaptans, including preparing the reactor for operation, supplying a stream of a mixture of gas to be purified and oxygen-containing gas to the reactor inlet, contacting the supplied mixture with a catalyst solution with the release of finely dispersed sulfur into the catalyst solution, supplying a suspension of sulfur to the separation unit with subsequent separation of sulfur from the catalyst solution, characterized in that a disk film reactor is used with means for distributing a mixture of hydrocarbon and oxygen-containing gas throughout the volume of the reactor, the gas to be purified and oxygen-containing gas are supplied through a mixer, after sulfur is separated in the separation unit from the catalyst solution solution catalyst is returned to the reactor.

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