Sulfur cycle methane hydrogen sulfide hydrogen production process capable of reducing reaction carbon deposition under pressurization

Abstract

The invention relates to the technical field of hydrogen production, in particular to a sulfur circulation methane hydrogen sulfide hydrogen production process capable of reducing reaction carbon deposition under pressurization, which comprises the following steps: (1) mixing CH4, H2S and circulating S2 steam to react to obtain reaction gas I; (2) separating the reaction gas I obtained in the step (1) to obtain reaction gas II and S2, taking the obtained S2 as a reaction material in the step (1), separating the reaction gas II through a rectifying tower, and condensing from the tower top to obtain reaction gas III; (3) compressing and cooling the reaction gas III, enabling the reaction gas III to enter an absorption tower to be in contact with low-temperature methanol, and separating to obtain hydrogen-rich gas and sulfur-rich methanol; (4) heating the sulfur-rich methanol to obtain sulfur-poor methanol and absorbed H2S gas; and (5) introducing the sulfur-poor methanol and H2S gas into the gas stripping tower, circulating the H2S to the step (1), cooling the sulfur-poor methanol, and introducing the cooled sulfur-poor methanol into the absorption tower in the step (4).

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production, and in particular to a sulfur cycle methane hydrogen sulfide hydrogen production process for reducing reaction carbon deposition under pressure. Background Art

[0002] High-quality and clean energy development is imperative, and natural gas, as the cleanest fossil energy, is of utmost importance. my country is rich in natural gas resources, but sulfur-containing natural gas accounts for 25% of the total proven natural gas, which is mainly distributed in the Sichuan Basin, Ordos, Tarim Basin and offshore oil and gas fields. Hydrogen sulfide (H2S) is not only a highly toxic gas that has serious damage to the human body, but also natural gas must be desulfurized before it can be further utilized, otherwise it will bring risks to oil and gas extraction, transportation and storage. In summary, the presence of hydrogen sulfide has a negative effect on our health and resource utilization that cannot be ignored.

[0003] In industry, most of the methods used are to separate and enrich H2S by physical or chemical methods, and then use the Claus process to treat and convert H2S, converting H2S into sulfur and water. However, in this process, the product obtained does not have a high economic value, and the hydrogen element in H2S is wasted. In order to realize the resource utilization of hydrogen sulfide, researchers have conducted many studies and developed a series of hydrogen sulfide production technologies such as photocatalysis, electrocatalysis, and photothermal. However, the maturity of most technologies is still at a low level. Only H2SMR technology has the highest maturity, has reached the basis of industrialization, and has the most development prospects. Its reaction process is: CH4+H2S=CS2+H2.

[0004] Compared with H2S decomposition, the CH4 and H2S reforming hydrogen production process has a high reaction conversion rate and high hydrogen production under the same conditions. In order to improve production efficiency and reduce the volume of the reactor, industrial production often performs pressurization during the gas reaction process. However, during the reaction process after pressurization, the thermal decomposition of methane will intensify, resulting in the generation of a large amount of carbon. Excessive carbon deposition will cause carbon to adsorb on the surface of the catalyst, covering the active sites, resulting in a decrease in reaction rate and catalyst deactivation. In severe cases, carbon deposition will cause pipeline blockage, and improper handling will easily lead to industrial production safety accidents, and the hidden dangers are very serious. Therefore, in order to suppress carbon deposition, hydrogen sulfide must be excessive during the reaction process, and excessive hydrogen sulfide will increase the subsequent separation cost and cause environmental pollution. These problems have seriously affected the industrial development of methane hydrogen sulfide reforming to produce hydrogen.

[0005] Therefore, there is an urgent need in the art for a method to solve the problem of carbon deposition and excess hydrogen sulfide treatment under pressurized conditions. Summary of the invention

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a sulfur cycle methane hydrogen sulfide hydrogen production process under pressure to reduce reaction carbon deposition.

[0007] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0008] The present invention provides a sulfur cycle methane hydrogen sulfide hydrogen production process under pressure to reduce reaction carbon deposition, comprising the following steps:

[0009] (1) CH4, H2S and circulating S2 steam are mixed and reacted to obtain reaction gas I;

[0010] (2) separating the reaction gas I obtained in step (1) to obtain reaction gas II and S2, using the obtained S2 as the reaction material for step (1), separating the reaction gas II through a distillation tower, and condensing from the top of the tower to obtain reaction gas III;

[0011] (3) After being compressed and cooled, the reaction gas III enters an absorption tower to contact with low-temperature methanol to separate hydrogen-rich gas and sulfur-rich methanol;

[0012] (4) heating the sulfur-rich methanol to obtain sulfur-depleted methanol and absorbed H2S gas;

[0013] (5) The sulfur-depleted methanol and H2S gas are introduced into a gas stripping tower, and the H2S is circulated to step (1). The sulfur-depleted methanol is cooled and then enters the absorption tower in step (4).

[0014] In some embodiments, in step (1), the molar ratio of H2S to CH4 is 2.0-8.0, and the molar ratio of S2 to CH4 is 0.1-1.5.

[0015] In some embodiments, in step (1), the reaction temperature is 900°C-1700°C.

[0016] In some embodiments, in step (1), the reaction pressure is 10-30 bar.

[0017] In some embodiments, in step (2), the gas at the top outlet of the distillation tower is separated by a condenser to obtain reaction gas III, the condensation temperature range is selected from -20°C to -15°C, and the CS2 recovered from the bottom of the distillation tower is further separated by a reboiler, and the reboiler temperature is selected from 70°C to 100°C.

[0018] In some embodiments, in step (3), the molar ratio of the reaction gas III to the low-temperature methanol in the absorption tower is 1:4-1:7.

[0019] In some embodiments, in step (3), the low-temperature methanol absorption temperature range in the absorption tower is -20°C to -70°C.

[0020] In some embodiments, in step (3), the low-temperature methanol and reaction gas III in the absorption tower are reacted at a pressure range of 3-6 MPa.

[0021] The present invention has the following beneficial effects:

[0022] (1) In order to increase production in industrial processes, it is inevitable to pressurize the gas reaction process. However, the thermal decomposition of methane (CH4=C+2H2) in the reaction of methane and hydrogen sulfide under pressurized conditions will inevitably produce a large amount of carbon deposits. Carbon deposits not only reduce the activity of the catalyst and reduce the generation of CS2, but also block the pipeline and cause explosions and other dangers. By adding S2 steam in a cycle, the generation of carbon deposits can be reduced.

[0023] (2) After the reaction gas I is separated from S2 in the separator, it is re-steamed as the initial reaction material. According to the reaction CH4+2S2=CS2+2H2S, it can be seen that adding S2 during the reaction process can make the carbon element in methane react with sulfur to produce carbon disulfide with higher economic value.

[0024] (3) According to the reaction CH4+2H2S=4H2+CS2. In the methane hydrogen sulfide reforming reaction, hydrogen sulfide is often excessive, which is to reduce carbon deposition during the pressurization process and prevent the carbon generated by the decomposition of methane from accumulating on the catalyst surface. However, sulfur is added to the reaction system so that the carbon in the methane reacts with sulfur, thereby reducing or even completely eliminating carbon deposition. Thanks to this, the proportion of hydrogen sulfide added to the reaction system can be reduced, reducing safety hazards while also reducing the economic cost of hydrogen sulfide treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the sulfur cycle hydrogen production process system and process flow of the present invention;

[0026] Figure 2 An energy supply system for the sulfur cycle hydrogen production process of the present invention;

[0027] Figure 3 This is a carbon deposition diagram of methane hydrogen sulfide reactor B5 in comparative example 6, wherein the blue portion in the diagram indicates no carbon deposition, and the red portion indicates severe carbon deposition;

[0028] Figure 4 This is a carbon deposition diagram in the methane hydrogen sulfide reactor B5 of Example 3, wherein the blue portion in the diagram indicates no carbon deposition, and the red portion indicates severe carbon deposition;

[0029] Figure 5 This is a carbon deposition diagram in the methane hydrogen sulfide reactor B5 of Example 6, wherein the blue portion in the diagram indicates no carbon deposition, and the red portion indicates severe carbon deposition;

[0030] Figure 6 This is a carbon deposition diagram in the methane hydrogen sulfide reactor B5 of Example 4, wherein the blue portion in the diagram indicates no carbon deposition, and the red portion indicates severe carbon deposition. DETAILED DESCRIPTION

[0031] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0032] In order to better understand the device of the present invention, the following is the preparation method of the device and the specific implementation process. It should be noted that the entire implementation method is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0033] In order to solve the problem of carbon deposition in the process of producing hydrogen from methane hydrogen sulfide, the present invention proposes the following method: Figure 1As shown, 25°C, 100% methane and 100% hydrogen sulfide (H2S and CH4 mixed molar ratio 4.0-7.0) raw gas are mixed through a methane hydrogen sulfide mixer B1, and then the raw gas is passed into a methane hydrogen sulfide sulfurizing mixer B2, mixed with 100% sulfur vapor (S2 and CH4 mixed molar ratio 0.1-1.5, temperature 450°C-500°C), and then continued to be passed into a first heat exchanger B3, in which the reaction gas I and the sulfurized raw gas exchange heat to obtain a reaction gas I of 700°C-800°C and a sulfurized raw gas of 600°C-800°C. The sulfur-added raw gas after heat exchange is introduced into the first heater B4 for preheating to 800°C-900°C, and then enters the methane hydrogen sulfide reactor B5, and reacts at a reaction pressure of 10-30 bar and a reaction temperature of 1300°C-1600°C to obtain a reaction gas I which is a mixed gas of S2, H2S, H2, and CS2 at 1300°C-1600°C. The reaction gas I is heat-exchanged with the sulfur-added raw gas introduced later through the first heat exchanger B3, and then cooled to 650°C-800°C, and then cooled to 100°C-135°C through the first cooler B6. S2 and CS2 are separated in the sulfur separator B7. The H2S, H2, and CS2 mixed gas is separated, and the separated S2 is vaporized (450℃-500℃) and circulated through the second heater B10 to the methane hydrogen sulfide sulfurizing mixer B2. After separation, the reaction gas II is passed through the second cooler B8 to obtain a mixed gas of H2S, CS2, and H2 at 100℃-135℃. The reaction gas II passes through the rectification tower B9 at an operating pressure of 15-20bar. After the reaction gas II is condensed (-20℃~-15℃) and reboiled (70℃-100℃), liquid CS2 and reaction gas III are obtained. The reaction gas III is a mixed gas of H2 and H2S at 85℃. The reaction gas III passes through the compressor B12 at an operating pressure of 10-15bar, and after compression, it passes through the third cooler B13 and is passed to the hydrogen sulfide absorption tower B15. The absorption liquid is low-temperature methanol, and the absorption gas-liquid molar ratio is 1:4-1:7 of acid gas low-temperature methanol. The pressure of the hydrogen sulfide absorption tower B15 is 3-6MPa, and the temperature of the low-temperature methanol is controlled at -60℃~-45℃. After the absorption is completed, sulfur-rich methanol and H2 are obtained. After the sulfur-rich methanol is separated from H2, the sulfur-rich methanol is passed into the first heat exchanger B16 for high temperature and low pressure (45℃-60℃, 1bar-3bar) treatment and then enters the hydrogen sulfide stripping tower B17 to separate the hydrogen sulfide and methanol. The obtained H2S gas is recycled to the methane hydrogen sulfide mixer B1, and the obtained methanol is recycled to the hydrogen sulfide absorption tower B15 through the fourth cooler B11 (-60℃~-45℃) and the absorption liquid suction pump B14.

[0034] like Figure 2In the energy supply system shown in the figure, the heat flow HEAT-2 is heated to 500°C through the second heat exchanger A4, and the air and methane are heated to 400°C-500°C through the first heat exchanger A3 and the third heat exchanger A5 respectively to reach the methane combustion temperature. After being introduced into the methane-air mixer A1, they are introduced into the methane-air reactor A2 and burned in the methane-air reactor A2 to supply energy for the hydrogen production system. The heat flow HEAT-1 and the heat flow HEAT-3 provide gas preheating energy for the first heat exchanger A3 and the third heat exchanger A5 respectively. The steam VP is heated to 450-550°C steam VP-1 through the seventh heat exchanger A9, which provides energy for the second heater B10. The steam VP is heated to 800-900°C steam VP-2 through the fourth heat exchanger A6, which provides energy for the first heater B4. The steam VP-2 is heated to 1600-1700°C steam VP-3 through the fifth heat exchanger A7, which provides energy for the methane hydrogen sulfide reactor B5. The steam VP-3 is cooled to 45-60°C steam VP-4 through the sixth heat exchanger A8, which provides energy for the distillation tower B9 and the hydrogen sulfide stripping tower B17.

[0035] Example 1

[0036] The raw gas is introduced, wherein the CH4 concentration is 100%, and the introduction flow rate is 1kmol / h; the H2S concentration is 100%, and the introduction flow rate is 6kmol / h. The molar ratio of CH4 to H2S in the raw gas is 1:6, and the raw gas mixed in the methane hydrogen sulfide mixer B1 is introduced into the methane hydrogen sulfide sulfurizing mixer B2 to mix with the circulating S2 steam, wherein the S2 steam concentration is 100%, and the flow rate is 0.1kmol / h. In the methane hydrogen sulfide sulfurizing mixer B2, the CH4 to S2 molar ratio is 10:1 (S2 steam temperature 450°C). After mixing, it is continuously introduced into the first heat exchanger B3, and the reaction gas I and the sulfurized raw gas are heat exchanged in the first heat exchanger B3 to obtain 800°C reaction gas I and 600°C sulfurized raw gas. The sulfur-added raw gas after heat exchange is introduced into the first heater B4 for preheating to 800°C, and then enters the methane hydrogen sulfide reactor B5, and reacts at a reaction pressure of 20 bar and a reaction temperature of 1500°C to obtain a reaction gas I which is a mixed gas of S2, H2S, H2, and CS2 at 1500°C. The reaction gas I is heat-exchanged with the sulfur-added raw gas introduced later through the first heat exchanger B3, cooled to 800°C, and then cooled to 135°C through the first cooler B6. S2 and H2S are separated in the sulfur separator B7. The H2, CS2 mixed gas is separated, the separated S2 is vaporized (450°C) and circulated through the second heater B10 to the methane hydrogen sulfide sulfurizing mixer B2, and after separation, the reaction gas II is passed through the second cooler B8 to obtain a mixed gas of H2S, CS2 and H2 at 135°C. The reaction gas II passes through the rectification tower B9 at an operating pressure of 15 bar. After the reaction gas II is condensed (-20°C) and reboiled (85°C), liquid CS2 and reaction gas III are obtained. The reaction gas III is a mixed gas of H2 and H2S at 85°C. The reaction gas III passes through the compressor B12 at an operating pressure of 10 bar, and after compression, it passes through the third cooler B13 and is passed to the hydrogen sulfide absorption tower B15. The absorption liquid is low-temperature methanol, and the absorption gas-liquid molar ratio is 1:4 acid gas low-temperature methanol. The pressure of the hydrogen sulfide absorption tower B15 is 6MPa, and the temperature of the low-temperature methanol is controlled at -45°C. After the absorption is completed, sulfur-rich methanol and H2 are obtained. After the sulfur-rich methanol is separated from H2, the sulfur-rich methanol is passed into the first heat exchanger B16 for high-temperature and low-pressure (45°C, 1bar) treatment and then enters the hydrogen sulfide stripping tower B17 to separate hydrogen sulfide from methanol. The obtained H2S gas is recycled to the methane hydrogen sulfide mixer B1, and the obtained methanol is recycled to the hydrogen sulfide absorption tower B15 through the fourth cooler B11 (-45°C) and the absorption liquid suction pump B14.

[0037] After simulation with chemical simulation software Aspen Plus V11, the data showed: C production was 0 kmol / h, H2 production was 3.83 kmol / h, and CS2 production was 0.983 kmol / h; CH4 conversion rate was 98.32%, H2S conversion rate was 31.11%, H2 productivity was 47.9%, CS2 productivity was 98.3%, and S2 conversion rate was -1.64%.

[0038] Example 2

[0039] The raw gas is introduced, wherein the CH4 concentration is 100%, and the introduction flow rate is 1kmol / h; the H2S concentration is 100%, and the introduction flow rate is 4kmol / h. The molar ratio of CH4 to H2S in the raw gas is 1:4, and the raw gas mixed in the methane hydrogen sulfide mixer B1 is introduced into the methane hydrogen sulfide sulfurizing mixer B2 to mix with the circulating S2 steam, wherein the S2 steam concentration is 100%, and the flow rate is 0.4kmol / h. In the methane hydrogen sulfide sulfurizing mixer B2, the CH4 to S2 molar ratio is 5:2 (S2 steam temperature 450°C). After mixing, it is continuously introduced into the first heat exchanger B3, and the reaction gas I and the sulfurized raw gas are heat exchanged in the first heat exchanger B3 to obtain 800°C reaction gas I and 600°C sulfurized raw gas. The sulfur-added raw gas after heat exchange is introduced into the first heater B4 for preheating to 800°C, and then enters the methane hydrogen sulfide reactor B5, and reacts at a reaction pressure of 10 bar and a reaction temperature of 1600°C to obtain a reaction gas I which is a mixed gas of S2, H2S, H2, and CS2 at 1600°C. The reaction gas I is heat-exchanged with the sulfur-added raw gas introduced later through the first heat exchanger B3, cooled to 800°C, and then cooled to 135°C through the first cooler B6. S2 and H2S are separated in the sulfur separator B7. The H2, CS2 mixed gas is separated, the separated S2 is vaporized (450°C) and circulated through the second heater B10 to the methane hydrogen sulfide sulfurizing mixer B2, and after separation, the reaction gas II is passed through the second cooler B8 to obtain a mixed gas of H2S, CS2 and H2 at 135°C. The reaction gas II passes through the rectification tower B9 at an operating pressure of 15 bar. After the reaction gas II is condensed (-20°C) and reboiled (85°C), liquid CS2 and reaction gas III are obtained. The reaction gas III is a mixed gas of H2 and H2S at 85°C. The reaction gas III passes through the compressor B12 at an operating pressure of 10 bar, and after compression, it passes through the third cooler B13 and is passed to the hydrogen sulfide absorption tower B15. The absorption liquid is low-temperature methanol, and the absorption gas-liquid molar ratio is 1:4 acid gas low-temperature methanol. The pressure of the hydrogen sulfide absorption tower B15 is 6MPa, and the temperature of the low-temperature methanol is controlled at -45°C. After the absorption is completed, sulfur-rich methanol and H2 are obtained. After the sulfur-rich methanol is separated from H2, the sulfur-rich methanol is passed into the first heat exchanger B16 for high-temperature and low-pressure (45°C, 1bar) treatment and then enters the hydrogen sulfide stripping tower B17 to separate hydrogen sulfide from methanol. The obtained H2S gas is recycled to the methane hydrogen sulfide mixer B1, and the obtained methanol is recycled to the hydrogen sulfide absorption tower B15 through the fourth cooler B11 (-45°C) and the absorption liquid suction pump B14.

[0040] After simulation with chemical simulation software Aspen Plus V11, the data showed: C production was 0 kmol / h, H2 production was 3.58 kmol / h, and CS2 production was 0.993 kmol / h; CH4 conversion rate was 99.39%, H2S conversion rate was 39.8%, H2 productivity was 59.6%, CS2 productivity was 99.4%, and S2 conversion rate was -9.07%.

[0041] Example 3

[0042] The raw gas is introduced, wherein the CH4 concentration is 100%, and the flow rate is 1kmol / h; the H2S concentration is 100%, and the flow rate is 4kmol / h. The molar ratio of CH4 to H2S in the raw gas is 1:4, and the raw gas mixed in the methane hydrogen sulfide mixer B1 is introduced into the methane hydrogen sulfide sulfurizing mixer B2 to mix with the circulating S2 steam, wherein the S2 steam concentration is 100%, and the flow rate is 1.3kmol / h. After mixing, the CH4 and S2 molar ratio is 1:1.3 (S2 steam temperature 450°C). After mixing, it continues to be introduced into the first heat exchanger B3, and the reaction gas I and the sulfurized raw gas are heat exchanged in the first heat exchanger B3 to obtain 800°C reaction gas I and 600°C sulfurized raw gas. The sulfur-added raw gas after heat exchange is introduced into the first heater B4 for preheating to 800°C, and then enters the methane hydrogen sulfide reactor B5, and reacts at a reaction pressure of 10 bar and a reaction temperature of 1400°C to obtain a reaction gas I which is a mixed gas of S2, H2S, H2, and CS2 at 1400°C. The reaction gas I is heat-exchanged with the sulfur-added raw gas introduced later through the first heat exchanger B3, cooled to 800°C, and then cooled to 135°C through the first cooler B6. S2 and H2S are separated in the sulfur separator B7. The H2, CS2 mixed gas is separated, the separated S2 is vaporized (450°C) and circulated through the second heater B10 to the methane hydrogen sulfide sulfurizing mixer B2, and after separation, the reaction gas II is passed through the second cooler B8 to obtain a mixed gas of H2S, CS2 and H2 at 135°C. The reaction gas II passes through the rectification tower B9 at an operating pressure of 15 bar. After the reaction gas II is condensed (-20°C) and reboiled (85°C), liquid CS2 and reaction gas III are obtained. The reaction gas III is a mixed gas of H2 and H2S at 85°C. The reaction gas III passes through the compressor B12 at an operating pressure of 10 bar, and after compression, it passes through the third cooler B13 and is passed to the hydrogen sulfide absorption tower B15. The absorption liquid is low-temperature methanol, and the absorption gas-liquid molar ratio is 1:4 acid gas low-temperature methanol. The pressure of the hydrogen sulfide absorption tower B15 is 6MPa, and the temperature of the low-temperature methanol is controlled at -45°C. After the absorption is completed, sulfur-rich methanol and H2 are obtained. After the sulfur-rich methanol is separated from H2, the sulfur-rich methanol is passed into the first heat exchanger B16 for high-temperature and low-pressure (45°C, 1bar) treatment and then enters the hydrogen sulfide stripping tower B17 to separate hydrogen sulfide from methanol. The obtained H2S gas is recycled to the methane hydrogen sulfide mixer B1, and the obtained methanol is recycled to the hydrogen sulfide absorption tower B15 through the fourth cooler B11 (-45°C) and the absorption liquid suction pump B14.

[0043] After simulation with chemical simulation software Aspen Plus V11, the data showed: C production was 0 kmol / h, H2 production was 2.67 kmol / h, and CS2 production was 0.992 kmol / h; CH4 conversion rate was 99.26%, H2S conversion rate was 17.14%, H2 productivity was 44.51%, CS2 productivity was 99.26%, and S2 conversion rate was -2.45%.

[0044] Example 4

[0045] The raw gas is introduced, wherein the CH4 concentration is 100%, and the flow rate is 1kmol / h; the H2S concentration is 100%, and the flow rate is 7kmol / h. The molar ratio of CH4 to H2S in the raw gas is 1:7, and the raw gas mixed in the methane hydrogen sulfide mixer B1 is introduced into the methane hydrogen sulfide sulfurizing mixer B2 to mix with the circulating S2 steam, wherein the S2 steam concentration is 100%, and the flow rate is 0.6kmol / h. After mixing, the CH4 and S2 molar ratio is 5:3 (S2 steam temperature 450°C). After mixing, continue to be introduced into the first heat exchanger B3, in which the reaction gas I and the sulfurized raw gas are heat exchanged to obtain 800°C reaction gas I and 600°C sulfurized raw gas. The sulfur-added raw gas after heat exchange is introduced into the first heater B4 for preheating to 800°C, and then enters the methane hydrogen sulfide reactor B5, and reacts at a reaction pressure of 30 bar and a reaction temperature of 1400°C to obtain a reaction gas I which is a mixed gas of S2, H2S, H2, and CS2 at 1400°C. The reaction gas I is heat-exchanged with the sulfur-added raw gas introduced later through the first heat exchanger B3, cooled to 800°C, and then cooled to 135°C through the first cooler B6. S2 and H2S are separated in the sulfur separator B7. The H2, CS2 mixed gas is separated, the separated S2 is vaporized (450°C) and circulated through the second heater B10 to the methane hydrogen sulfide sulfurizing mixer B2, and after separation, the reaction gas II is passed through the second cooler B8 to obtain a mixed gas of H2S, CS2 and H2 at 135°C. The reaction gas II passes through the rectification tower B9 at an operating pressure of 15 bar. After the reaction gas II is condensed (-20°C) and reboiled (85°C), liquid CS2 and reaction gas III are obtained. The reaction gas III is a mixed gas of H2 and H2S at 85°C. The reaction gas III passes through the compressor B12 at an operating pressure of 10 bar, and after compression, it passes through the third cooler B13 and is passed to the hydrogen sulfide absorption tower B15. The absorption liquid is low-temperature methanol, and the absorption gas-liquid molar ratio is 1:4 acid gas low-temperature methanol. The pressure of the hydrogen sulfide absorption tower B15 is 6MPa, and the temperature of the low-temperature methanol is controlled at -45°C. After the absorption is completed, sulfur-rich methanol and H2 are obtained. After the sulfur-rich methanol is separated from H2, the sulfur-rich methanol is passed into the first heat exchanger B16 for high-temperature and low-pressure (45°C, 1bar) treatment and then enters the hydrogen sulfide stripping tower B17 to separate hydrogen sulfide from methanol. The obtained H2S gas is recycled to the methane hydrogen sulfide mixer B1, and the obtained methanol is recycled to the hydrogen sulfide absorption tower B15 through the fourth cooler B11 (-45°C) and the absorption liquid suction pump B14.

[0046] After simulation with chemical simulation software Aspen Plus V11, the data showed: C production was 0 kmol / h, H2 production was 3.30 kmol / h, CS2 production was 0.974 kmol / h; CH4 conversion rate was 97.4%, H2S conversion rate was 19.27%, H2 productivity was 36.63%, CS2 productivity was 97.42%, and S2 conversion rate was -7.89%.

[0047] Example 5

[0048] The raw gas is introduced, wherein the CH4 concentration is 100%, and the flow rate is 1kmol / h; the H2S concentration is 100%, and the flow rate is 5kmol / h. The molar ratio of CH4 to H2S in the raw gas is 1:5, and the raw gas mixed in the methane hydrogen sulfide mixer B1 is introduced into the methane hydrogen sulfide sulfurizing mixer B2 to mix with the circulating S2 steam, wherein the S2 steam concentration is 100%, and the flow rate is 0.7kmol / h. After mixing with a molar ratio of CH4 to S2 of 10:7 (S2 steam temperature 450°C), it is continuously introduced into the first heat exchanger B3, and the reaction gas I and the sulfurized raw gas are heat exchanged in the first heat exchanger B3 to obtain 800°C reaction gas I and 600°C sulfurized raw gas. The sulfur-added raw gas after heat exchange is introduced into the first heater B4 for preheating to 800°C, and then enters the methane hydrogen sulfide reactor B5, and reacts at a reaction pressure of 20 bar and a reaction temperature of 1500°C to obtain a reaction gas I which is a mixed gas of S2, H2S, H2, and CS2 at 1500°C. The reaction gas I is heat-exchanged with the sulfur-added raw gas introduced later through the first heat exchanger B3, cooled to 800°C, and then cooled to 135°C through the first cooler B6. S2 and H2S are separated in the sulfur separator B7. The H2, CS2 mixed gas is separated, the separated S2 is vaporized (450°C) and circulated through the second heater B10 to the methane hydrogen sulfide sulfurizing mixer B2, and after separation, the reaction gas II is passed through the second cooler B8 to obtain a mixed gas of H2S, CS2 and H2 at 135°C. The reaction gas II passes through the rectification tower B9 at an operating pressure of 15 bar. After the reaction gas II is condensed (-20°C) and reboiled (85°C), liquid CS2 and reaction gas III are obtained. The reaction gas III is a mixed gas of H2 and H2S at 85°C. The reaction gas III passes through the compressor B12 at an operating pressure of 10 bar, and after compression, it passes through the third cooler B13 and is passed to the hydrogen sulfide absorption tower B15. The absorption liquid is low-temperature methanol, and the absorption gas-liquid molar ratio is 1:4 acid gas low-temperature methanol. The pressure of the hydrogen sulfide absorption tower B15 is 6MPa, and the temperature of the low-temperature methanol is controlled at -45°C. After the absorption is completed, sulfur-rich methanol and H2 are obtained. After the sulfur-rich methanol is separated from H2, the sulfur-rich methanol is passed into the first heat exchanger B16 for high-temperature and low-pressure (45°C, 1bar) treatment and then enters the hydrogen sulfide stripping tower B17 to separate hydrogen sulfide from methanol. The obtained H2S gas is recycled to the methane hydrogen sulfide mixer B1, and the obtained methanol is recycled to the hydrogen sulfide absorption tower B15 through the fourth cooler B11 (-45°C) and the absorption liquid suction pump B14.

[0049] After simulation with chemical simulation software Aspen Plus V11, the data showed: C production was 0 kmol / h, H2 production was 3.25 kmol / h, and CS2 production was 0.987 kmol / h; CH4 conversion rate was 98.65%, H2S conversion rate was 25.47%, H2 productivity was 46.38%, CS2 productivity was 98.65%, and S2 conversion rate was -1.23%.

[0050] Example 6

[0051] The raw gas is introduced, wherein the CH4 concentration is 100%, and the flow rate is 1kmol / h; the H2S concentration is 100%, and the flow rate is 6kmol / h. The molar ratio of CH4 to H2S in the raw gas is 1:6, and the raw gas mixed in the methane hydrogen sulfide mixer B1 is introduced into the methane hydrogen sulfide sulfurizing mixer B2 to mix with the circulating S2 steam, wherein the S2 steam concentration is 100%, and the flow rate is 0.7kmol / h. After mixing with the molar ratio of CH4 to S2 of 10:7 (S2 steam temperature 450°C), it is continuously introduced into the first heat exchanger B3, and the reaction gas I and the sulfurized raw gas are heat exchanged in the first heat exchanger B3 to obtain 800°C reaction gas I and 600°C sulfurized raw gas. The sulfur-added raw gas after heat exchange is introduced into the first heater B4 for preheating to 800°C, and then enters the methane hydrogen sulfide reactor B5, and reacts at a reaction pressure of 20 bar and a reaction temperature of 1400°C to obtain a reaction gas I which is a mixed gas of S2, H2S, H2, and CS2 at 1400°C. The reaction gas I is heat-exchanged with the sulfur-added raw gas introduced later through the first heat exchanger B3, cooled to 800°C, and then cooled to 135°C through the first cooler B6. S2 and H2S are separated in the sulfur separator B7. The H2, CS2 mixed gas is separated, the separated S2 is vaporized (450°C) and circulated through the second heater B10 to the methane hydrogen sulfide sulfurizing mixer B2, and after separation, the reaction gas II is passed through the second cooler B8 to obtain a mixed gas of H2S, CS2 and H2 at 135°C. The reaction gas II passes through the rectification tower B9 at an operating pressure of 15 bar. After the reaction gas II is condensed (-20°C) and reboiled (85°C), liquid CS2 and reaction gas III are obtained. The reaction gas III is a mixed gas of H2 and H2S at 85°C. The reaction gas III passes through the compressor B12 at an operating pressure of 10 bar, and after compression, it passes through the third cooler B13 and is passed to the hydrogen sulfide absorption tower B15. The absorption liquid is low-temperature methanol, and the absorption gas-liquid molar ratio is 1:4 acid gas low-temperature methanol. The pressure of the hydrogen sulfide absorption tower B15 is 6MPa, and the temperature of the low-temperature methanol is controlled at -45°C. After the absorption is completed, sulfur-rich methanol and H2 are obtained. After the sulfur-rich methanol is separated from H2, the sulfur-rich methanol is passed into the first heat exchanger B16 for high-temperature and low-pressure (45°C, 1bar) treatment and then enters the hydrogen sulfide stripping tower B17 to separate hydrogen sulfide from methanol. The obtained H2S gas is recycled to the methane hydrogen sulfide mixer B1, and the obtained methanol is recycled to the hydrogen sulfide absorption tower B15 through the fourth cooler B11 (-45°C) and the absorption liquid suction pump B14.

[0052] After simulation with chemical simulation software Aspen Plus V11, the data showed: C production was 0 kmol / h, H2 production was 3.23 kmol / h, and CS2 production was 0.982 kmol / h; CH4 conversion rate was 98.15%, H2S conversion rate was 21.055%, H2 productivity was 40.33%, CS2 productivity was 98.15%, and S2 conversion rate was -1.04%.

[0053] In addition, in the above-mentioned embodiments 1-6, when S2 is separated in the sulfur separator B7 and is insufficient for reflux to the methane hydrogen sulfide sulfurizing mixer B2, S2 steam is introduced into the methane hydrogen sulfide sulfurizing mixer B2 from the outside to meet the usage demand.

[0054] Comparative Example 1

[0055] Compared with Example 1, other conditions were the same, except that the reaction pressure of the methane hydrogen sulfide reactor B5 was changed to 1 bar and the S2 steam was not introduced into the methane hydrogen sulfide sulfurizing mixer B2.

[0056] The data obtained by simulation of Comparative Example 1 by chemical simulation software Aspen Plus V11 show that the C production is 0 kmol / h, the H2 production is 4.00 kmol / h, and the CS2 production is 0.999 kmol / h; the CH4 conversion rate is 99.9%, the H2S conversion rate is 33.4%, the H2 productivity is 50.05%, the CS2 productivity is 99.99%, and the S2 conversion rate is 7.34%. It can be seen that in Example 1 (CH4 conversion rate is 98.32%, H2S conversion rate is 31.11%, H2 productivity is 47.9%, and CS2 productivity is 98.3%), although the CH4 conversion rate, H2S conversion rate, H2 productivity and CS2 productivity slightly decreased by 1%, 2%, 3% and 1% respectively after pressurization by 20 times. However, it is also because of the 20-fold pressurization condition that the theoretical gas processing capacity and output are increased by 20 times, which is more in line with industrial requirements. Although carbon deposition is more serious under pressurized conditions, no carbon deposition is generated due to the introduction of sulfur vapor in Example 1. At the same time, the S2 conversion rate in Example 1 is negative, indicating that part of S2 is converted into CS2, achieving S2 appreciation.

[0057] Comparative Example 2

[0058] Compared with Example 1, other conditions are the same, except that S2 steam is not introduced into the methane hydrogen sulfide sulfurizing mixer B2.

[0059] The data obtained by simulation of Comparative Example 2 using chemical simulation software Aspen Plus V11 show that the C production is 0.022 kmol / h, the H2 production is 3.88 kmol / h, and the CS2 production is 0.959 kmol / h; the CH4 conversion rate is 98.2%, the H2S conversion rate is 32.00%, the H2 production rate is 48.55%, the CS2 production rate is 95.9%, and the S2 conversion rate is 3.82%. The C production of Example 1 is 0 kmol / h. It can be seen that under the condition of pressurization, since no S2 steam is introduced into Comparative Example 2, part of the methane that has not reacted with hydrogen sulfide will undergo a pyrolysis reaction, resulting in an increase in carbon deposition during the reaction process.

[0060] Comparative Example 3

[0061] Compared with Example 2, other conditions are the same, the molar ratio of CH4 to H2S in the raw gas is changed to 1:8 and S2 steam is not introduced into the methane hydrogen sulfide sulfurizing mixer B2.

[0062] The data of Comparative Example 3 obtained after simulation by chemical simulation software Aspen Plus V11 showed: C production was 0 kmol / h, H2 production was 3.99 kmol / h, and CS2 production was 0.999 kmol / h; CH4 conversion rate was 99.9%, H2S conversion rate was 25.02%, H2 productivity was 39.9%, CS2 productivity was 99.9%, and S2 conversion rate was 3.08%. Through Example 2 (C production is 0 kmol / h, H2 production is 3.58 kmol / h, CS2 production is 0.994 kmol / h; CH4 conversion rate is 99.39%, H2S conversion rate is 39.8%, H2 productivity is 59.6%, CS2 productivity is 99.4%, S2 conversion rate is -9.07%), it can be found that although the carbon deposition in the reaction process can be reduced by excessive H2S in the reaction process, a large amount of hydrogen sulfide increases the processing cost. Compared with Example 2, the processing amount of hydrogen sulfide increases by 25%, but the unreacted hydrogen sulfide unprocessed amount increases by 150%, which seriously increases the industrial processing cost.

[0063] Comparative Example 4

[0064] Compared with Example 3, other conditions are the same, and the reaction temperature of the methane hydrogen sulfide reactor B5 is changed to 1300°C.

[0065] The data of Comparative Example 4 obtained after simulation with chemical simulation software Aspen Plus V11 showed: C production was 0.156 kmol / h, H2 production was 2.35 kmol / h, and CS2 production was 0.833 kmol / h; CH4 conversion rate was 98.9%, H2S conversion rate was 9.15%, H2 productivity was 39.08%, CS2 productivity was 83.3%, and S2 conversion rate was -2.45%. Example 3 (C production is 0 kmol / h, H2 production is 2.67 kmol / h, CS2 production is 0.992 kmol / h; CH4 conversion rate is 99.26%, H2S conversion rate is 17.14%, H2 productivity is 44.51%, CS2 productivity is 99.26%, S2 conversion rate is -2.45%.) It can be found that increasing the reaction temperature also helps to reduce carbon deposition. At the same time, except for the conversion rate of S2, all other conversion rates are improved, indicating that the reaction is changed to an endothermic reaction. The higher the temperature, the more the reaction proceeds in the forward direction.

[0066] Comparative Example 5

[0067] Compared with Example 4, other conditions are the same, the concentration of S2 steam added to the methane hydrogen sulfide sulfurizing mixer B2 is changed to 100%, the flow rate is 1 kmol / h, and the molar ratio of CH4 to S2 is 1:1.

[0068] The data of Comparative Example 5 obtained after simulation by chemical simulation software Aspen Plus V11 showed: C production was 0 kmol / h, H2 production was 2.94 kmol / h, CS2 production was 0.986 kmol / h; CH4 conversion rate was 98.55%, H2S conversion rate was 13.87%, H2 productivity was 32.69%, CS2 productivity was 98.55%, and S2 conversion rate was -1.25%. Example 4 (C production is 0 kmol / h, H2 production is 3.30 kmol / h, CS2 production is 0.974 kmol / h; CH4 conversion rate is 97.4%, H2S conversion rate is 19.27%, H2 productivity is 36.63%, CS2 productivity is 97.42%, S2 conversion rate is -7.89%), it can be found that with the increase of S2, the H2 productivity and H2S conversion rate of Example 5, S2 conversion rate compared with Example 4 are greatly reduced, respectively reduced by 4% and 5%, 6%, however, CS2 productivity and CH4 conversion rate increase is small, only 1%. It can be seen that excessive S2 will inhibit the decomposition of hydrogen sulfide and cause the hydrogen sulfide treatment capacity to decrease, and the S2 introduction ratio should be adjusted to achieve the purpose of reducing carbon deposition and avoiding inhibition of hydrogen sulfide conversion.

[0069] Comparative Example 6

[0070] Compared with Example 4, other conditions were the same, except that the reaction pressure of the methane hydrogen sulfide reactor B5 was changed to 1 bar and the S2 steam was not introduced into the methane hydrogen sulfide sulfurizing mixer B2.

[0071] Comparative Example 6 was simulated by chemical simulation software Aspen Plus V11, and the data showed that the C production was 0 kmol / h, the H2 production was 4.00 kmol / h, and the CS2 production was 0.999 kmol / h; the CH4 conversion rate was 99.99%, the H2S conversion rate was 28.5%, the H2 productivity was 44.46%, the CS2 productivity was 79.52%, and the S2 conversion rate was 2.51%. Example 4 (C production was 0 kmol / h, H2 production was 3.30 kmol / h, and CS2 production was 0.974 kmol / h; CH4 conversion rate was 97.4%, H2S conversion rate was 19.27%, H2 productivity was 36.63%, CS2 productivity was 97.42%, and S2 conversion was -7.89%), it can be seen that under the condition of low reaction temperature (<1500°C), the pressurized conditions are not conducive to the conversion of hydrogen sulfide and the production of hydrogen. However, pressurization is a must for industrial production, so we need to control the appropriate reaction temperature and the ratio of CH4:S2 steam to achieve the purpose of reducing carbon deposition and avoiding inhibition of hydrogen sulfide conversion.

[0072] Figure 3 Corresponding to the carbon deposition diagram during the reaction of Example 6, it can be found that under a reaction pressure of 1 bar, the carbon deposition range during the reaction is small, and when the CH4:H2S molar ratio is greater than 1:3.5, no carbon deposition is produced in the methane hydrogen sulfide reactor B5. Although there is no carbon deposition in the case of no pressure, no pressure does not meet the industrial processing volume requirements, and the value of sulfur is not increased.

[0073] Figure 4 Corresponding to the carbon deposition diagram during the reaction of Example 3, it can be found that under a reaction pressure of 10 bar, the carbon deposition range increases significantly, and when the CH4:H2S molar ratio is greater than 1:5.5, no carbon deposition is produced in the methane hydrogen sulfide reactor B5. In Example 3, by adding S2 steam with a flow rate of 1.3 kmol / h and a concentration of 100%, the CH4 to S2 molar ratio is 1:1.3, so that when CH4:H2S is equal to 1:4, no carbon deposition is produced in the methane hydrogen sulfide reactor B5, wherein the circulating sulfur will not only increase in value to carbon disulfide, but also reduce the proportion of hydrogen sulfide in the reaction, thereby reducing the cost of handling excess hydrogen sulfide.

[0074] Figure 5Corresponding to the carbon deposition diagram during the reaction of Example 6, it can be found that under a reaction pressure of 20 bar, the carbon deposition range continues to increase, and when the molar ratio of CH4 to H2S is greater than 1:6.5, no carbon deposition is produced in the methane hydrogen sulfide reactor B5. In Example 6, by adding S2 steam with a flow rate of 0.7 kmol / h and a concentration of 100%, the molar ratio of CH4 to S2 is 10:7, so that when CH4:H2S is equal to 1:6, no carbon deposition is produced in the methane hydrogen sulfide reactor B5, wherein the circulating sulfur will not only increase in value to carbon disulfide, but also reduce the proportion of hydrogen sulfide in the reaction, thereby reducing the cost of handling excess hydrogen sulfide.

[0075] Figure 6 Corresponding to the carbon deposition diagram during the reaction of Example 4, it can be found that under a reaction pressure of 30 bar, the carbon deposition range is further increased. When the molar ratio of CH4 to H2S is greater than 1:7.5, no carbon deposition is produced in the methane hydrogen sulfide reactor B5. Example 4, by adding S2 steam with a concentration of 100% and a flow rate of 0.6 kmol / h to the raw gas. The molar ratio of CH4 to S2 is 5:3, so that the molar ratio of CH4:H2S is 1:7. There is also no carbon deposition in the methane hydrogen sulfide reactor B5.

[0076] pass Figure 3 , Figure 4 , Figure 5 , Figure 6 It can be seen that increasing the molar ratio of CH4 to H2S in the raw gas can reduce carbon deposition, but it will greatly increase the cost of hydrogen sulfide treatment. However, the present invention uses the circulating sulfur vapor produced by the reaction to greatly reduce carbon deposition, and the sulfur in the value-added reaction is carbon disulfide. Figure 3 , Figure 4 , Figure 5 , Figure 6 It is a carbon deposition diagram of CH4 and H2S added to S2 in different proportions at different pressures at a reaction temperature of 1400°C in the methane hydrogen sulfide reactor B5. However, it also shows the overall trend of the effect of pressurization on carbon deposition during the reforming of CH4 and H2S, that is, the greater the pressure in the methane hydrogen sulfide reactor B5, the more serious the carbon deposition during the reaction.

[0077] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0078] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A sulfur cycle methane hydrogen sulfide hydrogen production process under pressure to reduce carbon deposition. It is characterized in that The following steps are involved: (1) CH 4 , H 2 S and Cyclic S 2 The steam is mixed and reacted to obtain reaction gas I; (2) Separating the reaction gas I obtained in step (1) to obtain reaction gas II and S 2 , the obtained S 2 As the reaction material of step (1), the reaction gas II is separated by a distillation tower and condensed from the top of the tower to obtain the reaction gas III; (3) After being compressed and cooled, the reaction gas III enters an absorption tower to contact with low-temperature methanol to separate hydrogen-rich gas and sulfur-rich methanol; (4) The sulfur-rich methanol is heated to obtain sulfur-depleted methanol and the absorbed H 2 S gas; (5) Reducing sulfur-depleted methanol and H 2 S gas is introduced into the stripping tower, H 2 S is circulated to step (1), and the sulfur-depleted methanol is cooled and then enters the absorption tower in step (4).

2. The hydrogen production process according to claim 1, It is characterized in that In step (1), the H 2 S and CH 4 The molar ratio is 2.0-8.0, the S 2 With CH 4 The molar ratio is 0.1-1.

5.

3. The hydrogen production process according to claim 1, It is characterized in that In step (1), the reaction temperature is 900°C-1700°C.

4. The hydrogen production process according to claim 1, It is characterized in that In step (1), the reaction pressure is 10-30 bar.

5. The hydrogen production process according to claim 1, It is characterized in that In step (2), the gas at the top outlet of the distillation tower is separated by a condenser to obtain reaction gas III, and the condensation temperature range is selected from -20°C to -15°C. The CS recovered at the bottom of the distillation tower is 2 The separation is continued through the reboiler, and the reboiler temperature is selected to be 70°C-100°C.

6. The hydrogen production process according to claim 1, It is characterized in that In step (3), the molar ratio of the reaction gas III to the low-temperature methanol in the absorption tower is 1:4-1:

7.

7. The hydrogen production process according to claim 1, It is characterized in that In step (3), the low-temperature methanol absorption temperature range in the absorption tower is -20°C to -70°C.

8. The hydrogen production process according to claim 1, It is characterized in that In step (3), the low-temperature methanol in the absorption tower and the reaction gas III are reacted at a pressure range of 3-6 MPa.

Images