Process system for co-production of solid wax, liquid hydrocarbon and hydrogen by fischer-tropsch synthesis of biosynthetic gas

Abstract

This utility model relates to the field of biosynthetic gas treatment technology, specifically disclosing a process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis. The system comprises a pretreatment system, a blower system, a compression system, a shift converter system, a desulfurization system, an MDEA decarbonization system, a PSA hydrogen extraction system, a desorbed gas compression system, a fine desulfurization and pressurization system, and a Fischer-Tropsch synthesis system, connected in sequence. This process system utilizes biosynthetic gas from the pyrolysis and gasification of municipal solid waste, producing solid wax, liquid hydrocarbons, and hydrogen through a combination of technologies including Fischer-Tropsch synthesis and pressure swing adsorption. This system converts organic matter in waste into high-value-added chemicals such as solid wax, liquid hydrocarbons, and hydrogen, achieving resource utilization and reducing environmental pollution. Furthermore, the process system can adjust the types and quantities of products according to market demand to maximize economic benefits.

Description

Technical Field

[0001] This utility model relates to the field of biosynthetic gas treatment technology, and in particular to a process system for the co-production of solid wax, liquid hydrocarbons and hydrogen from biosynthetic gas Fischer-Tropsch synthesis. Background Technology

[0002] With the public's significantly increased awareness of environmental protection and resource conservation, higher standards have been set for waste treatment technologies. Against this backdrop, traditional waste treatment methods, including landfill, composting, and incineration, have gradually revealed their respective shortcomings. First, while landfilling is simple and easy to implement, it requires a large amount of land resources, which is particularly uneconomical in today's increasingly scarce land environment. Second, although composting is a relatively environmentally friendly method, it processes a relatively small volume of waste and has low efficiency, making it difficult to cope with the ever-increasing volume of waste. Finally, while incineration can effectively reduce waste volume, it is prone to secondary pollution during the process, especially the emission of highly toxic substances such as dioxins, which causes great harm to the environment and poses a significant obstacle to industrial applications. Therefore, finding more efficient and environmentally friendly waste treatment technologies has become an urgent problem for society to solve.

[0003] To address the challenges of municipal solid waste (MSW) treatment, domestic researchers are actively exploring fluidized bed pyrolysis gasification technology for organic waste. This process involves pyrolyzing organic waste at high temperatures, followed by a condensation step to convert the resulting gases into new gaseous and solid forms. From both theoretical and practical perspectives, this method can effectively reduce the formation of harmful substances such as dioxins. Simultaneously, during pyrolysis gasification, most heavy metals dissolve into the ash, significantly reducing the emissions of these harmful substances. The mixed gas obtained from treating MSW in this way is called biosynthetic gas. This gas mainly consists of hydrogen, methane, carbon monoxide, carbon dioxide, and nitrogen, but also contains impurities such as tar, sulfur, chlorine, ammonia, and siloxanes. Currently, biosynthetic gas is still in its early stages of industrial application, and many countries worldwide are actively researching and exploring industrialization pathways for converting waste into hydrogen. Nevertheless, this field is currently still largely in the research and demonstration phase. At present, the mainstream methods for treating MSW remain combustion for power generation or urban heating. Although there are some industrial plants in China that produce hydrogen from municipal solid waste pyrolysis gas, their application scope remains very limited. Given this situation, a key challenge for engineers is how to efficiently utilize the biosynthetic gas produced by municipal solid waste pyrolysis gasification and create greater economic value through this method. Utility Model Content

[0004] This invention provides a process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis. The biosynthetic gas generated from the pyrolysis and gasification of municipal solid waste is sequentially purified through a series of processes, including carbon-hydrogen ratio adjustment, pressure swing adsorption for hydrogen extraction, and Fischer-Tropsch synthesis. Through the synergistic co-production of high-purity hydrogen, liquid hydrocarbons, and solid wax by multiple systems, high-value utilization of organic waste resources and low carbon emissions are achieved.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis includes, in sequence, a pretreatment system A, a blower system B, a pretreatment system C, a compression system D, a shift conversion system E, a desulfurization system F, an MDEA decarbonization system G, a PSA hydrogen extraction system H, a desorbed gas compression system I, a fine desulfurization and pressurization system J, and a Fischer-Tropsch synthesis system K. The pretreatment system A is used for preliminary oil removal treatment of the biosynthetic gas produced from the pyrolysis and gasification of municipal solid waste. The blower system B is used to pressurize the pretreated biosynthetic gas and split it through pipelines, one branch supplying fuel gas externally and the other branch entering the pretreatment system C. The pretreatment system C is used for further oil removal and desulfurization treatment of the pressurized biosynthetic gas. The compression system D is used for… The purified biosynthetic gas is further pressurized; the shift system E is used to adjust the molar ratio of hydrogen and carbon monoxide to obtain shift gas; the desulfurization system F is used to desulfurize the shift gas; the MDEA decarbonization system G is used to absorb and remove carbon dioxide and separate the by-product carbon dioxide through pipelines; the PSA hydrogen extraction system H is used to remove hydrogen and adjust the hydrogen production ratio to obtain PSA desorbed gas, and the carbon-rich gas that does not participate in hydrogen extraction is transported through pipelines to the outlet pipeline of the desorbed gas compression system I; the desorbed gas compression system I is used to pressurize the PSA desorbed gas; the fine desulfurization and pressurization system J is used to further pressurize and finely desulfurize the PSA desorbed gas; the Fischer-Tropsch synthesis system K is used to condense and separate solid wax and liquid hydrocarbons, and at the same time, the obtained purge gas is reused as fuel gas.

[0007] Furthermore, the pretreatment system A includes an electrostatic precipitator and a fiber bed mist eliminator connected together. The electrostatic precipitator is equipped with a heating device at the bottom and a rinsing device at the top. The fiber bed mist eliminator is filled with a loose mesh structure woven from corrosion-resistant and high-temperature-resistant fibers.

[0008] Furthermore, the pretreatment system C removes tar from the biosynthetic gas to ≤5 mg / Nm³. 3 Hydrogen sulfide was removed to ≤50 mg / Nm³. 3 The pretreatment system C includes an oil removal tower and a desulfurization device connected together. The oil removal tower adopts dry oil removal and is filled with coke, activated carbon and aluminosilicate composite adsorption packing. The desulfurization device adopts dry desulfurization or wet desulfurization.

[0009] Furthermore, the conversion system E employs a wide-temperature sulfur-resistant conversion catalyst, and dynamically controls the molar ratio of hydrogen to carbon monoxide within a range of ±0.2 of 2:1 by adjusting the steam conversion reaction between carbon monoxide and water vapor.

[0010] Furthermore, the desulfurization system F adopts dry desulfurization and uses a desulfurization tower, which is filled with a composite desulfurizing agent of coke and activated carbon.

[0011] Furthermore, the MDEA decarbonization system G employs a two-stage absorption process using methyl diethanolamine solution, with the lower stage using a semi-lean solution for washing and the upper stage using a regenerated lean solution for washing.

[0012] Furthermore, the PSA hydrogen extraction system H includes 6 to 12 adsorption towers, and the adsorbent is regenerated by rinsing or vacuuming, with the pressure equalization cycle being 1 to 6 times.

[0013] Furthermore, the fine desulfurization and pressurization system J pressurizes the finely desulfurized mixed gas to a gauge pressure of 4-6 MPa, and the operating pressure of the Fischer-Tropsch synthesis system K is consistent with the output pressure of the fine desulfurization and pressurization system J, which is a gauge pressure of 4-6 MPa.

[0014] Furthermore, the fine desulfurization and pressurization system J uses a fine desulfurization tower to remove hydrogen sulfide from the gas to ≤4ppb, and the fine desulfurization tower is filled with a composite fine desulfurizing agent of zinc oxide and copper oxide.

[0015] A method for the co-production of solid wax, liquid hydrocarbons and hydrogen from biosynthetic gas Fischer-Tropsch synthesis is also provided, comprising the following steps:

[0016] (1) Pretreatment for tar removal: Biosynthetic gas generated from the pyrolysis and gasification of municipal solid waste is introduced into pretreatment system A, and preliminary oil removal is carried out by an electrostatic precipitator and a fiber bed mist precipitator to remove most of the tar.

[0017] (2) Blower pressurization: The pretreated biosynthetic gas is pressurized to 20-60 kPa gauge pressure by blower system B and split into two streams, one stream is supplied as fuel gas and the other stream enters pretreatment system C;

[0018] (3) Pretreatment for oil removal and desulfurization: The biosynthetic gas entering the pretreatment system C passes sequentially through an oil removal tower and a desulfurization unit to remove tar to ≤5mg / Nm³. 3 Hydrogen sulfide was removed to ≤50 mg / Nm³. 3 ;

[0019] (4) Compressor pressurization: The purified biosynthetic gas is further pressurized by the compression system D to a gauge pressure of 1.5 to 2.5 MPa;

[0020] (5) Shift reaction: The pressurized gas enters the shift system E. Under the action of a wide-temperature sulfur-resistant shift catalyst, the molar ratio of hydrogen to carbon monoxide is controlled at 2:1±0.2 by adjusting the steam shift reaction of carbon monoxide and water vapor to obtain shift gas.

[0021] (6) Desulfurization treatment: The shift gas is introduced into the dry desulfurization tower of desulfurization system F, where a composite desulfurizing agent of coke and activated carbon is used to remove hydrogen sulfide to ≤1mg / Nm³. 3 ;

[0022] (7) MDEA decarbonization: The desulfurized gas enters the MDEA decarbonization system G, where carbon dioxide is removed to ≤50ppm and the by-product carbon dioxide is separated.

[0023] (8) PSA hydrogen extraction: The decarbonized gas enters the PSA hydrogen extraction system H and is separated into product hydrogen through the pressure swing adsorption process of 6 to 12 adsorption towers; the carbon-rich gas in the decarbonized gas that did not participate in hydrogen extraction is directly transported to the outlet pipeline of the desorption gas compression system I through the pipeline, and is combined with the remaining PSA desorption gas after hydrogen extraction and then enters the desorption gas compression system I.

[0024] (9) Desorption gas compression: The PSA desorption gas is pressurized to 1.5-2.5 MPa gauge pressure by the desorption gas compression system I;

[0025] (10) Fine desulfurization and pressurization: The desorbed gas after pressurization enters the fine desulfurization and pressurization system J, and through the fine desulfurization tower filled with zinc oxide and copper oxide composite desulfurizing agent, the hydrogen sulfide is removed to ≤4ppb, and further pressurized to 4-6 MPa gauge pressure;

[0026] (11) Fischer-Tropsch synthesis: The gas after fine desulfurization and pressurization is introduced into the Fischer-Tropsch synthesis system K. Under the conditions of 4-6 MPa gauge pressure and 160-200℃, hydrocarbon products are synthesized by catalysis. Solid wax and liquid hydrocarbons are obtained by condensation separation, and the off-gas is reused as fuel gas.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The process system for producing solid wax, liquid hydrocarbons and co-produced hydrogen from biosynthetic gas Fischer-Tropsch synthesis of this utility model mainly consists of a pretreatment system, a blower system, a compression system, a conversion system, a desulfurization system, an MDEA decarbonization system, a PSA hydrogen extraction system, a desorbed gas compression system, a fine desulfurization and pressurization system, and a Fischer-Tropsch synthesis system. The pretreatment system effectively removes impurities from biosynthesis gas using electrostatic precipitators and fiber bed mist eliminators, ensuring high efficiency in subsequent treatment. The pretreatment system further performs deep oil removal and desulfurization to ensure that components such as hydrogen sulfide in the biosynthesis gas meet process requirements. The compression and shift reaction systems increase the concentration of hydrogen and CO in the biosynthesis gas through compression and shift reactions, providing high-quality raw materials for the subsequent PSA hydrogen extraction system. The desulfurization system and MDEA decarbonization system deeply remove sulfides and carbon dioxide from the biosynthesis gas, ensuring gas purity. The PSA hydrogen extraction system can produce high-purity hydrogen according to the needs of downstream hydrogen users, while simultaneously sending the extracted gas to the desorbed gas compression system. The fine desulfurization and pressurization system further removes trace amounts of sulfides from the gas, improving its purity. The Fischer-Tropsch synthesis system uses carbon monoxide and hydrogen to synthesize liquid hydrocarbons and solid waxes under specific temperature and pressure conditions, achieving full conversion of waste resources and the production of high-value-added chemicals. The working principle of the entire system is to use the biosynthetic gas generated by the pyrolysis and gasification of municipal solid waste, and after pretreatment, compression, conversion, desulfurization, hydrogen extraction, fine desulfurization, and pressurization, solid wax, liquid hydrocarbons and hydrogen are finally obtained through Fischer-Tropsch synthesis, which greatly improves the economic and environmental benefits of waste treatment. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process system for the co-production of solid wax, liquid hydrocarbons and hydrogen from biosynthetic gas Fischer-Tropsch synthesis in an embodiment of this utility model. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] Example

[0032] like Figure 1As shown, this utility model provides a process system for producing high-purity hydrogen and co-producing biogas from biogas crude syngas, including a purification unit 1, a hydrocarbon adjustment unit 2, an acid removal unit 3, a methane upgrading unit 4, a hydrogen recycling and purification unit 5, and a methane recycling and purification unit 6 connected in sequence. Specifically, the biogas is connected to the pretreatment system A via pipeline 1; the pretreatment system A is connected to the blower system B via pipeline; the blower system B is connected to the pretreatment system C via pipeline; the pressurized biogas at the outlet of the blower system B is sent out as external fuel gas via pipeline 2; the pretreatment system C is connected to the compression system D via pipeline; the compression system D is connected to the conversion system E via pipeline; the conversion system E is connected to the desulfurization system F via pipeline; the desulfurization system F is connected to the M... The MDEA decarbonization system G is connected; the CO2 absorbed by the MDEA decarbonization system G is vented locally at a high point through pipeline 3; the MDEA decarbonization system G is connected to the PSA hydrogen extraction system H through pipeline; the MDEA decarbonization system G is connected to the outlet pipeline of the desorbed gas compression system I through pipeline 5; the product hydrogen produced by the PSA hydrogen extraction system H is sent out through pipeline 4; the PSA hydrogen extraction system H is connected to the desorbed gas compression system I through pipeline; the desorbed gas compression system I is connected to the fine desulfurization and pressurization system J through pipeline; the fine desulfurization and pressurization system J is connected to the Fischer-Tropsch synthesis system K through pipeline; the liquid hydrocarbons produced by the Fischer-Tropsch synthesis system K are sent out through pipeline 6; the solid wax produced by the Fischer-Tropsch synthesis system K is sent out through pipeline 7; the purge gas of the Fischer-Tropsch synthesis system K is sent out as fuel gas through pipeline 8.

[0033] The pretreatment system A is used for preliminary oil removal of biosynthetic gas generated from the pyrolysis and gasification of municipal solid waste at 2-4 kPa(G) and 40°C. Pretreatment system A includes a connected electrostatic precipitator and a fiber bed mist eliminator. The biosynthetic gas passes through these devices to remove most of the tar. The electrostatic precipitator employs a honeycomb structure, which effectively improves the equipment's collection efficiency. A steam heating device is installed at its bottom, which not only helps maintain the normal operating temperature of the equipment but also prevents tar deposition inside to some extent. A dedicated flushing device is installed at the top of the electrostatic precipitator for periodically cleaning the equipment surface to maintain its optimal working condition. As for the fiber bed mist eliminator, its internal loose fiber bed adopts a core-type structure, which is fixed in the equipment by a tube sheet, ensuring its stability and durability. The fiber bed is a loose mesh structure woven from extremely fine fibers, possessing a very large specific surface area. This gives it a significant coagulation effect on fine dust-laden droplets, thus achieving extremely high separation efficiency. In addition, this fiber bed mist eliminator has advantages such as easy cleaning, corrosion resistance of materials, and ability to withstand high temperatures, making it perform well in various industrial applications.

[0034] The blower system B is used to pressurize the pretreated biosynthetic gas to 20-60 kPa(G). The blower system B uses a blower, and the pressurized biosynthetic gas is divided into two paths: one path is supplied as fuel gas through pipeline 2, and the other path enters the pretreatment system C.

[0035] The pretreatment system C performs deep oil removal and desulfurization pretreatment on the pressurized biosyngas. The pretreatment system C includes connected oil removal towers and desulfurization units; specifically, it comprises two connected dry oil removal towers and one dry desulfurization tower. The pressurized biosyngas undergoes tar removal to ≤5 mg / Nm³ in the dry oil removal towers. 3 The oil removal tower is filled with tar adsorption packing materials such as coke, activated carbon, and aluminosilicates. Pressurized biosynthesis gas is then passed through a desulfurization unit to remove hydrogen sulfide to ≤50 mg / Nm³. 3 The desulfurization unit adopts either dry or wet desulfurization methods depending on the hydrogen sulfide content of the biosynthetic gas.

[0036] The compression system D is used to further pressurize the purified biosynthetic gas to 1.5–2.5 MPa; the compressor used in compression system D is a reciprocating compressor or a centrifugal compressor. Specifically, two connected centrifugal compressors are used. The core objective of this step is to increase the working pressure of the purified biosynthetic gas. When selecting the pressure, the main considerations include the user's specific requirements for hydrogen pressure, as well as a comprehensive evaluation of multiple aspects such as the investment cost, energy consumption, and process removal efficiency of each unit.

[0037] The conversion system E is used to adjust the molar ratio of hydrogen and carbon monoxide to produce the desired converted gas. The conversion system E includes a feed preheater, a detoxification furnace, a humidifier, a primary conversion furnace, a waste heat boiler, a secondary conversion furnace, a heat exchanger assembly, and a cooling unit. The feed preheater receives biosynthetic gas (pressure 1.5–2.5 MPa(G), temperature approximately 130°C) from the compression system D, and heats the gas to 180–230°C through heat exchange. The outlet of the feed preheater is connected to the inlet of the detoxification furnace, where oxygen (O2 < 1 ppm), arsenic, chlorine, and other toxins are removed, and the temperature rises to approximately 300°C (the temperature rise depends on the impurity content). The gas from the detoxification furnace outlet enters the humidifier, where the temperature is reduced to approximately 220°C by spraying water / steam. The humidifier outlet is connected to the inlet of the first-stage shift converter, where the gas undergoes the main shift reaction under isothermal conditions (or adiabatic conditions depending on the feed gas conditions), and the shift converter outlet temperature is approximately 250°C. The heat generated by the shift reaction in the first-stage shift converter is transferred through the catalyst bed. The water heat transfer tube bundle produces 1.0–2.5 MPa (G) saturated steam as a byproduct. The water heat transfer tube bundle in the first-stage converter is connected to the waste heat boiler. The outlet of the first-stage converter is connected to the inlet of the second-stage converter to complete deep conversion (CO concentration is determined by hydrogen content, the purpose being to adjust the molar ratio of CO to H2). The outlet temperature is controlled at approximately 220°C. The heat exchanger group includes a deaerated water preheater and a demineralized water preheater. The gas from the second-stage converter outlet of the deaerated water preheater is cooled to approximately 180°C by the deaerated water preheater; the demineralized water preheater further cools it to 120°C. The cooling unit includes an air cooler and a water cooler. The outlet of the demineralized water preheater is connected to the air cooler, reducing the gas temperature to 60°C; the outlet of the air cooler is connected to the water cooler, ultimately cooling the converted gas to below 40°C before it is delivered to the desulfurization system F.

[0038] The feed preheater heats the compressed biosynthetic gas (approximately 130°C) to the catalytic reaction temperature (e.g., 180°C); the detoxification furnace contains deoxidizers and adsorbents to remove residual O2 (O2 < 1 ppm) and toxins such as arsenic and chlorine from the gas, raising the outlet temperature to approximately 300°C; the humidifier regulates the temperature of the high-temperature gas (e.g., reducing it to 220°C) by spraying water / steam and replenishing the gas with steam; the first-stage conversion furnace is filled with a wide-temperature, sulfur-resistant catalyst (e.g., Co-Mo based) to carry out the main conversion reaction under isothermal conditions (CO conversion rate 60%–80%), raising the outlet temperature to approximately 250°C; waste The hot boiler recovers the by-product steam from the reaction (pressure 1.0–2.5 MPa) while simultaneously cooling the gas to below 200°C. The second-stage shift converter further completes the deep shift (CO concentration ≤15%), employing an isothermal reactor or interstage cooling design, with the outlet temperature controlled at 220°C ± 10°C. The heat exchanger group includes a deaerated water preheater and a demineralized water preheater, recovering waste heat stage by stage (gas temperature drops from 220°C to 80°C). The cooling unit consists of an air cooler (air-cooled) and a water cooler (circulating water-cooled), ultimately reducing the shift gas temperature to below 40°C to meet the inlet requirements of the desulfurization system. This shift system E processes the high-pressure purified biogas under the action of a gas-solid phase catalyst, converting CO and water vapor into H2 and CO2. The purpose of this process is to obtain more hydrogen and adjust the hydrogen-to-carbon ratio in the shifted biogas to meet the requirements of Fischer-Tropsch synthesis. Its basic chemical reaction equation can be expressed as: CO + H2O = CO2 + H2. The conversion system E can flexibly adjust the main products of the unit according to changes in market conditions, thereby primarily adjusting the ratio of H2 to CO in the biosynthesis gas. When hydrogen is not produced, the conversion system E ensures that the ratio of H2 to CO in the converted biosynthesis gas is approximately 2:1, to suit the application scenarios of the Fischer-Tropsch synthesis unit.

[0039] The desulfurization system F is used for deep removal of H2S from the converted biosyngas. The desulfurization system F employs a dry desulfurization method, using a dry desulfurization tower filled with desulfurization adsorbents such as coke and activated carbon. The converted biosyngas passes through the desulfurization tower to remove H2S to ≤1 mg / Nm³. 3 .

[0040] The MDEA decarbonization system G is used to absorb and remove carbon dioxide and separate the byproduct carbon dioxide through pipelines. The MDEA decarbonization system G employs a two-stage absorption process using methyldiethanolamine solution (MDEA solution). The lower stage uses semi-lean liquor for washing, and the upper stage uses regenerated lean liquor for washing. The MDEA decarbonization system G removes CO2 from the decarbonized gas to below 50 ppm. Specifically, the MDEA decarbonization system G includes a raw gas-liquid separator, a two-stage absorption tower, a rich liquor flash tank, a lean-rich liquor heat exchanger, a regeneration tower, a lean liquor circulation pump, and a semi-lean liquor circulation pump. The feed gas-liquid separator is used to separate condensate entrained in the shifted gas; the two-stage absorption tower includes a lower absorption zone and an upper absorption zone. The lower absorption zone is filled with structured packing, and its inlet is connected to a semi-lean liquid circulation pump, which initially absorbs CO2 using a semi-lean MDEA solution (a mixture of lean and rich solutions); the upper absorption zone is filled with random packing, and its inlet is connected to a lean liquid cooler, which further removes CO2 to ≤50ppm using regenerated lean liquid; the rich liquid flash tank is used to receive the rich liquid (a CO2-rich MDEA solution) at the bottom of the absorption tower and releases dissolved gas by depressurization; the lean-rich liquid heat exchanger utilizes the high temperature at the bottom of the regeneration tower. The rich liquor after flash evaporation of the lean liquor is heated to raise its temperature to 100-110℃. The regeneration tower includes a reboiler and a top condenser. The reboiler is heated by steam (0.3-0.5 MPa(G)) to desorb CO2 from the rich liquor at 120-130℃. The top condenser condenses and dehydrates the desorbed CO2 gas to obtain high-purity CO2 (≥99.5%), which is vented through pipeline 3. The lean liquor circulation pump cools the lean liquor at the bottom of the regeneration tower to 40-50℃ and then pumps it to the upper section of the absorption tower. The semi-lean liquor circulation pump draws semi-lean liquor from the middle of the regeneration tower and directly delivers it to the lower section of the absorption tower.

[0041] The process of removing carbon dioxide using the MDEA decarbonization system G and separating the byproduct carbon dioxide through pipelines is as follows: The degassing gas first enters the feed gas-liquid separator for gas-liquid separation. The separated gas enters from the lower inlet of the absorber, is washed with semi-lean liquid in the lower absorption zone, and then enters the upper absorption zone. After washing with lean liquid again, purified gas is obtained and discharged from the top of the absorber and transported to the PSA hydrogen extraction system H. The carbon dioxide gas desorbed at the top of the regeneration tower is dehydrated by the top condenser and vented through pipeline 3 at the highest point. The rich liquid output from the bottom of the absorber is depressurized and flashed in the rich liquid flash tank, then heated by heat exchange with the high-temperature lean liquid in the rich-lean liquid heat exchanger before entering the middle of the regeneration tower. The high-temperature lean liquid at the bottom of the regeneration tower is pressurized by the lean liquid circulation pump, first cooled by heat exchange with the rich liquid in the rich-lean liquid heat exchanger, then cooled to 40-50°C by the lean liquid cooler, and finally transported to the upper inlet of the absorber tower. The semi-lean liquid in the middle of the regeneration tower is directly transported to the lower inlet of the absorber tower via the semi-lean liquid circulation pump. The high-temperature lean liquor at the bottom of the regeneration tower exchanges heat with the rich liquor in the lean-rich liquor heat exchanger, and then enters the lean liquor cooler for further cooling; the steam condensate from the reboiler is returned to the boiler for recycling through pipelines.

[0042] The PSA hydrogen extraction system H is used to remove hydrogen and adjust the hydrogen production ratio to obtain PSA desorbed gas. The carbon-rich gas that does not participate in hydrogen extraction is transported through pipelines to the outlet pipeline of the desorbed gas compression system I. The process flow of the PSA hydrogen extraction system H uses 6-12 adsorption towers, with 1-6 pressure equalization cycles. Adsorbent regeneration is achieved through rinsing or vacuuming. The PSA hydrogen extraction system H is designed to flexibly adjust its production load according to the company's internal hydrogen demand. This adjustment ensures that the system can efficiently meet the specific needs of downstream hydrogen users. The demand for hydrogen mainly comes from these users, who have clear requirements for the quantity and quality of hydrogen used. After completing the hydrogen production process, the PSA hydrogen extraction system H will have some residual purified biosynthetic gas. This residual gas is guided through pipeline 5 into the outlet pipeline of the desorbed gas compression system I. This design not only optimizes gas utilization efficiency but also reduces resource waste. Furthermore, the PSA hydrogen extraction system H has the capability to adjust the purity of produced hydrogen according to the needs of downstream hydrogen users, producing hydrogen with a purity between 99% and 99.999%. This high-purity hydrogen is not only suitable for general industrial applications but also meets the stringent requirements for hydrogen used in standard hydrogen fuel cells, thus enabling the widespread application of hydrogen energy.

[0043] The desorbed gas compression system I is used to pressurize the PSA desorbed gas; specifically, the desorbed gas compression system I pressurizes the PSA desorbed gas of the PSA hydrogen extraction system H to 1.5 to 2.5 MPa (G).

[0044] The fine desulfurization and pressurization system J is used to further pressurize and finely desulfurize the PSA desorbed gas. The system removes H2S from the purified and hydrogen-extracted PSA desorbed gas to ≤4 ppb, and then pressurizes the finely desulfurized PSA desorbed gas to 4–6 MPa(G). Specifically, the purified and hydrogen-extracted PSA desorbed gas passes through a fine desulfurization tower, where H2S is removed to ≤4 ppb. The fine desulfurization employs a dry desulfurization method, and the tower is filled with fine desulfurizing agents such as zinc oxide and copper oxide.

[0045] The Fischer-Tropsch synthesis system K is used to condense and separate solid waxes and liquid hydrocarbons, while simultaneously reusing the resulting purge gas as fuel gas. The Fischer-Tropsch synthesis system K is a process that synthesizes hydrocarbon products from carbon monoxide and hydrogen at 160–200°C and ~4.0 MPa pressure using a Co catalyst. The main products are divided into liquid products (gasoline and diesel components) and solid products (high-end synthetic waxes). The purge gas generated by the Fischer-Tropsch synthesis system K is transported externally as fuel gas through pipeline 8. Specifically, the Fischer-Tropsch synthesis system K includes a shell-and-tube coupled heat exchanger, a Fischer-Tropsch synthesis reactor, a multi-stage condenser, a gas-liquid-solid three-phase separator, a purge gas recirculation compressor, and a product collection tank.

[0046] In this process, the syngas from the desulfurization and pressurization system J is mixed with the circulating process gas from the multi-stage condenser outlet and then preheated to near the reaction temperature (160-200℃) in a shell-and-tube coupled heat exchanger. The preheated mixture is then sent to the Fischer-Tropsch synthesis reactor, where hydrocarbon synthesis is carried out under Co-based catalyst and ~4.0 MPa(G) conditions. The reactor outlet product is then sequentially cooled in a multi-stage condenser (temperature gradient controlled at 200℃→120℃→40℃) to separate liquid hydrocarbons and solid wax. The condensed gas-liquid-solid mixture enters a gas-liquid-solid three-phase separator. The liquid hydrocarbons are sent to a storage tank via pipeline 6, and the solid wax is sent for packaging via pipeline 7. The uncondensed gas is divided into two paths: one path is used as purge gas and supplied as fuel gas via pipeline 8; the other path is pressurized by the purge gas recirculation compressor and returned to the inlet of the shell-and-tube coupled heat exchanger for recirculation reaction.

[0047] The gasification feedstock gas conditions for the biosynthetic gas comprehensive utilization unit in a municipal solid waste harmless treatment project are as follows:

[0048] Components <![CDATA[H2]]> CO <![CDATA[CO2]]> <![CDATA[CH4]]> <![CDATA[O2]]> <![CDATA[N2]]> total Vol,% 32.5 39.7 6.4 19 0.4 2 100

[0049] 1. Biosynthetic gas contains saturated water.

[0050] 2. The tar content of biosynthetic gas is 300 mg / Nm³. 3 .

[0051] 3. Total sulfur content in biosynthetic gas: 300 mg / Nm³ 3 .

[0052] 4. Biosynthetic gas contains impurities such as siloxanes, ammonia, dioxins, chlorine, arsenic, and Ar.

[0053] The process system described in this embodiment of the invention is used to treat the above-mentioned biosynthetic gas, including the following steps:

[0054] (1) Pretreatment to remove tar: Biosynthetic gas from the external gas holder at 2-3 kPa (G) and 40°C is introduced into the pretreatment system A. The biosynthetic gas is removed by the electrostatic precipitator, fiber bed mist precipitator and other equipment in the pretreatment system A.

[0055] (2) Pressurization by blower: The pretreated biosynthetic gas is pressurized to 40 kPa (G) by the blower in blower system B. After pressurization, the biosynthetic gas is split into two paths: one is supplied as fuel gas; the other goes to pretreatment system C.

[0056] (3) Pretreatment for oil removal and desulfurization: The biosynthetic gas from the blower enters the pretreatment system C, where two dry oil removal towers remove tar from the biosynthetic gas to 1 mg / Nm³. 3 The gas then enters a dry desulfurization tower to remove H2S from the biosynthesis gas to 30–50 mg / Nm³.3 .

[0057] (4) Compressor pressurization: Biosynthetic gas at 30 kPa (G) and 40°C enters the two centrifugal compressors in the compression system D and is pressurized to 2.0 MPa (G).

[0058] (5) Conversion: The conversion system E, under the action of a gas-solid phase catalyst, converts CO and steam in biosynthetic gas into H2 and CO2, with the aim of obtaining more hydrogen. The reaction equation is as follows:

[0059] CO+H2O=CO2+H2△Ho298=-41.4KJ / mol

[0060] Specifically, the biosynthetic gas, pressurized by the centrifugal compressor in step 4, does not require cooling and maintains a temperature of approximately 130°C with a pressure of 2.0 MPa(G). First, this gas is heated in a feed preheater to approximately 180°C. After heating, the gas is introduced into a detoxification furnace for detoxification and deoxygenation, during which the outlet temperature rises to approximately 300°C. Next, the gas is cooled by water spraying through a humidifier, and a suitable amount of steam is added before entering the first stage of the shift converter for the shift reaction. After completing the first stage of the shift reaction, the gas enters a waste heat boiler to recover its heat as byproduct steam. Subsequently, the gas is cooled again in the feed preheater to approximately 200°C before entering the second stage of the shift converter to complete the remaining shift reaction. After the second stage reaction, the outlet temperature of the gas is approximately 220°C, and the carbon monoxide content is reduced to below 15%. Finally, the transformed gas will recover the remaining heat through a deoxygenated water preheater and a demineralized water preheater, and then be cooled by an air cooler and a water cooler, eventually reducing the temperature to about 40°C.

[0061] (6) Shifting and desulfurization: The shifted gas enters the dry desulfurization tower in desulfurization system F to remove hydrogen sulfide to 5 mg / Nm³. 3 the following.

[0062] (7) MDEA decarbonization: The gas decarbonized by the gas-liquid separator in the MDEA decarbonization system G separates the condensate and enters the lower part of the absorption tower. The gas is first washed with semi-lean liquid in the lower section of the absorption tower, and some CO2 and H2S are absorbed. Then it is washed with regenerated lean liquid in the upper section of the absorption tower to remove CO2 from the purified gas to below 50ppm.

[0063] (8) PSA Hydrogen Extraction: The decarbonized gas enters the adsorption tower in the PSA hydrogen extraction system H, which is currently in an adsorption state, from the bottom of the tower. During the continuous selective adsorption process by various adsorbents, various impurities are effectively adsorbed and removed. Hydrogen gas not captured by the adsorbents flows out from the top of the adsorption tower. This hydrogen gas is then pressure-stabilized by a pressure regulating system to ensure pressure stability before being sent to subsequent process stages. After the above treatment, high-purity hydrogen gas with a purity of over 99.999% can be obtained. This high-purity hydrogen gas has extremely high value in many industrial applications.

[0064] (9) Desorption gas compression: The pressure of the desorption gas after PSA hydrogen extraction is only ~0.03MPa(G). After being pressurized to 1.6MPa by a centrifugal or reciprocating compressor, it enters the fine desulfurization and pressurization unit to deeply remove sulfur from the desorption gas.

[0065] (10) Fine desulfurization and pressurization: The desorbed gas after pressurization contains trace amounts of organic sulfur, and the conversion unit cannot convert all organic sulfur into H2S. After conversion, the gas is relatively clean with a low content of organic sulfur, so only one stage of hydrogenation is required. The pressurized desorbed gas is heated to about 220-250°C through a gas-to-gas heat exchanger and a steam heater, and then enters the hydrogenation reactor. Here, the organic sulfur in the desorbed gas undergoes a hydrogenation reaction with hydrogen, and the organic sulfur is converted into inorganic sulfur.

[0066] The reaction equation is as follows:

[0067] Alkenes saturated C2H4 + H2 → C2H6

[0068] Thiols: RSH + H2 → RH + H2S

[0069] Sulfides: R1SR2 + 2H2 → R1H + R2H + H2S

[0070] Disulfide: R1SSR2 + 3H2 → R1H + R2H + 2H2S

[0071] Thiophene: C4H4S + 4H2 → C4H 10 +H2S

[0072] Carbon sulfide: CO + H2 → CO + H2S

[0073] Carbon disulfide: CS2 + 4H2 → CH4 + 2H2S

[0074] The pressurized desorbed gas undergoes a first-stage hydrogenation reaction to convert organic sulfur into hydrogen sulfide, using a cobalt-molybdenum hydrogenation catalyst. After hydrogenation, a zinc oxide desulfurizing agent is used to remove the total sulfur content in the purified gas to less than 4 ppb, meeting the sulfur requirements of the Fischer-Tropsch synthesis catalyst.

[0075] The desorbed gas after fine desulfurization is pressurized to about 4.0 MPa (G) by a centrifugal or reciprocating compressor and then enters the Fischer-Tropsch synthesis unit.

[0076] (11) Fischer-Tropsch Synthesis: Fischer-Tropsch synthesis (FTS) is a chemical process involving the conversion of carbon monoxide and hydrogen into hydrocarbon products under specific temperature and pressure conditions using a suitable catalyst. The basic chemical reaction of this process can be represented as follows:

[0077] nCO + (2n+1)H₂ → CnH 2n+2 +nH2O

[0078] The raw material syngas, after being processed in the gas handling unit, is combined with the process gas, which has undergone multi-stage condensation. This gas mixture then enters a shell-and-tube coupled heat exchanger, where it is preheated to near the temperature required for the reaction. After preheating, the mixture enters the Fischer-Tropsch synthesis reactor, where a chemical reaction occurs, ultimately producing Fischer-Tropsch synthesis products, including solid waxes and light hydrocarbons. Depending on the characteristics of the region where the company is located and changes in the market environment, these products can be combined and adjusted within a certain range to better adapt to market demands. Furthermore, Fischer-Tropsch products can be further processed according to the specific circumstances of niche markets, such as extracting elemental straight-chain alkanes. Synthetic waxes can also be further processed to prepare various specialty waxes, thereby increasing the product value by more than 30%.

[0079] After the above steps, the final material balance of the biosynthetic gas is shown in Table 1.

[0080] Table 1 Material Balance Sheet

[0081]

[0082] The Fischer-Tropsch synthesis product data sheet details the specific information of the various products generated during the Fischer-Tropsch synthesis process, as shown in Table 2:

[0083] Table 2 Data Sheet for Fischer-Tropsch Synthesis Products

[0084]

[0085]

[0086] In summary, the pretreatment system A in this invention effectively removes tar and most fine droplets from the biosynthetic gas using an electrostatic precipitator and a fiber bed mist eliminator, improving the efficiency of subsequent treatment steps and catalyst utilization. The blower system B pressurizes the purified biosynthetic gas to a specified pressure, ensuring the reaction conditions of the shift conversion system. The oil removal tower and desulfurization tower in the pretreatment system C further purify the biosynthetic gas, making it meet the requirements of subsequent Fehler-Tropsch synthesis. The compression system D uses a centrifugal compressor to pressurize the gas, improving its thermal efficiency and reducing energy consumption. The shift conversion system E uses a wide-temperature, sulfur-resistant shift catalyst for adiabatic or isothermal reactions, significantly increasing hydrogen yield and meeting market demands. The desulfurization system F employs dry desulfurization, effectively reducing the negative impact of sulfides on the catalyst; the MDEA decarbonization system G utilizes MDEA solution to remove carbon dioxide from biosynthetic gas, further purifying the gas; the PSA hydrogen extraction system H employs multiple adsorption towers and pressure equalization technology, improving the purity and yield of hydrogen to meet different application requirements; the desorbed gas compression system I pressurizes the desorbed gas from the PSA hydrogen extraction system, ensuring the continuity of the gas path; the fine desulfurization and pressurization system J further removes sulfides and pressurizes the system, ensuring the operating conditions of the Fischer-Tropsch synthesis system; the Fischer-Tropsch synthesis system K catalytically synthesizes hydrocarbon products under certain temperature and pressure conditions, producing a variety of products such as solid wax, liquid hydrocarbons, and hydrogen, achieving efficient resource utilization. Its working principle is as follows: the biosynthetic gas generated from the pyrolysis and gasification of municipal solid waste undergoes multiple steps such as pretreatment, pressurization, and purification before entering the conversion system to generate hydrogen. The hydrogen is then purified and distributed through the PSA hydrogen extraction system. The remaining gas continues to undergo Fischer-Tropsch synthesis to generate solid wax and liquid hydrocarbons. The entire process system works in concert to achieve efficient and comprehensive utilization of biosynthetic gas, reduce environmental pollution, and improve economic benefits.

[0087] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis, characterized in that, It includes a pretreatment system A, a blower system B, a pretreatment system C, a compression system D, a conversion system E, a desulfurization system F, an MDEA decarbonization system G, a PSA hydrogen extraction system H, a desorbed gas compression system I, a fine desulfurization and pressurization system J, and a Fischer-Tropsch synthesis system K, which are connected in sequence. The system comprises the following components: Pretreatment system A for preliminary oil removal from the biosynthetic gas produced by the pyrolysis and gasification of municipal solid waste; Blower system B for pressurizing the pretreated biosynthetic gas and splitting it through pipelines, with one branch supplying fuel gas and the other entering pretreatment system C; Pretreatment system C for further oil removal and desulfurization of the pressurized biosynthetic gas; Compression system D for further pressurizing the purified biosynthetic gas; Shift system E for adjusting the molar ratio of hydrogen and carbon monoxide to obtain shift gas; and Desulfurization system F for desulfurizing the shift gas. The process involves the following steps: the MDEA decarbonization system G absorbs and removes carbon dioxide, and separates the byproduct carbon dioxide through pipelines; the PSA hydrogen extraction system H removes hydrogen and adjusts the hydrogen production ratio to obtain PSA desorbed gas, while the carbon-rich gas that does not participate in hydrogen extraction is transported through pipelines to the outlet pipeline of the desorbed gas compression system I; the desorbed gas compression system I pressurizes the PSA desorbed gas; the fine desulfurization and pressurization system J further pressurizes and finely desulfurizes the PSA desorbed gas; and the Fischer-Tropsch synthesis system K condenses and separates solid wax and liquid hydrocarbons, while simultaneously reusing the obtained purge gas as fuel gas.

2. The process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis according to claim 1, characterized in that, The pretreatment system A includes an electrostatic precipitator and a fiber bed mist eliminator connected together. The electrostatic precipitator is equipped with a heating device at the bottom and a rinsing device at the top. The fiber bed mist eliminator is filled with a loose mesh structure woven from corrosion-resistant and high-temperature-resistant fibers.

3. The process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis according to claim 1, characterized in that, The pretreatment system C removes tar from the biosynthetic gas to ≤5 mg / Nm³. 3 Hydrogen sulfide removed to ≤ 50mg / Nm 3 The pretreatment system C includes an oil removal tower and a desulfurization device connected together. The oil removal tower adopts dry oil removal and is filled with coke, activated carbon and aluminosilicate composite adsorption packing. The desulfurization device adopts dry desulfurization or wet desulfurization.

4. The process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis according to claim 1, characterized in that, The conversion system E uses a wide-temperature sulfur-resistant conversion catalyst, and dynamically controls the molar ratio of hydrogen to carbon monoxide within a range of ±0.2 of 2:1 by adjusting the steam conversion reaction between carbon monoxide and water vapor.

5. The process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis according to claim 1, characterized in that, The desulfurization system F adopts dry desulfurization and uses a desulfurization tower, which is filled with a composite desulfurizing agent of coke and activated carbon.

6. The process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis according to claim 1, characterized in that, The MDEA decarbonization system G employs a two-stage absorption process using methyl diethanolamine solution, with the lower stage using a semi-lean solution for washing and the upper stage using a regenerated lean solution for washing.

7. The process system for the co-production of solid wax, liquid hydrocarbons, and hydrogen from biosynthetic gas Fischer-Tropsch synthesis according to claim 1, characterized in that, The PSA hydrogen extraction system H includes 6 to 12 adsorption towers. The adsorbent is regenerated by rinsing or vacuuming, and the pressure equalization is performed 1 to 6 times.

8. The process system for the co-production of solid wax, liquid hydrocarbons and hydrogen from biosynthetic gas Fischer-Tropsch synthesis according to claim 1, characterized in that, The fine desulfurization and pressurization system J pressurizes the finely desulfurized mixed gas to a gauge pressure of 4-6 MPa. The operating pressure of the Fischer-Tropsch synthesis system K is consistent with the output pressure of the fine desulfurization and pressurization system J, which is 4-6 MPa.

9. The process system for the co-production of solid wax, liquid hydrocarbons and hydrogen from biosynthetic gas Fischer-Tropsch synthesis according to claim 8, characterized in that, The fine desulfurization and pressurization system J uses a fine desulfurization tower to remove hydrogen sulfide from the gas to ≤4ppb. The fine desulfurization tower is filled with a composite fine desulfurizing agent of zinc oxide and copper oxide.

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