Multi-production system of coupling gasification of ammonium carbamate and biomass

Abstract

This invention relates to the field of waste gas treatment technology and discloses a combined gasification system for ammonium carbamate and biomass, comprising a pyrolysis system, a boiler system, and a gasification system. The pyrolysis system includes a pyrolysis furnace, a biomass silo connected to the pyrolysis furnace, and a denitrification agent treatment unit. The pyrolysis furnace is used to pyrolyze ammonium carbamate and biomass materials to produce flue gas, pyrolysis gas, and pyrolysis char. The boiler system includes a boiler body and is used to receive flue gas and pyrolysis gas for denitrification. The gasification system includes a fluidized bed, a waste heat boiler, a shift converter, a low-temperature methanol washing unit, a methanol synthesis unit, and a desorption unit connected in series. The fluidized bed receives pyrolysis char and gasifies it to produce crude syngas. The crude syngas is cooled, shifted, and washed before outputting hydrogen and carbon monoxide, ultimately synthesizing methanol. This invention can reduce boiler NOx generation and carbon emissions, while simultaneously achieving green combined gasification of ammonium carbamate and methanol through the gasification system.

Description

Technical Field

[0001] This invention belongs to the field of waste gas treatment technology, specifically relating to a multi-product system for the coupled gasification of ammonium carbamate and biomass. Background Technology

[0002] With increasingly stringent requirements for ultra-low emissions of industrial flue gas, mainstream SCR and SNCR denitrification technologies rely on liquid ammonia or urea, posing risks of ammonia escape and secondary pollution. The urea-to-ammonia process has high water and energy consumption, with water vaporization heat accounting for 30%-50% of total energy consumption. It also easily generates byproducts such as isocyanate and biuret, causing pipeline corrosion and blockage, resulting in high operating costs. Related technologies have failed to deeply couple biomass thermochemical conversion with flue gas denitrification and carbon resource recycling, making it difficult to simultaneously achieve low-NOx and low-carbon combustion in boilers, full-component utilization of biomass, and co-production of green chemicals. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a polygeneration system for the coupled gasification of ammonium carbamate and biomass. This polygeneration system can reduce NOx generation and carbon emissions from boilers, while simultaneously achieving the green co-production of ammonium carbamate and methanol through coordination with the gasification system.

[0004] The polygeneration system for co-generation of ammonium carbamate and biomass gasification according to an embodiment of the present invention includes a pyrolysis system, a boiler system, and a gasification system. The pyrolysis system includes a pyrolysis furnace, a biomass silo connected to the pyrolysis furnace, and a denitrification agent treatment unit. The denitrification agent treatment unit is used to supply solid ammonium carbamate to the pyrolysis furnace. The biomass silo is used to supply biomass material to the pyrolysis furnace. The pyrolysis furnace is used to pyrolyze the ammonium carbamate and the biomass material to produce flue gas, pyrolysis gas, and pyrolysis char. The boiler system includes a boiler body connected to the gas phase outlet of the pyrolysis furnace and used to receive the flue gas and pyrolysis gas for denitrification of the boiler body. The gasification system includes… The system comprises a fluidized bed, a waste heat boiler, a conversion system, a low-temperature methanol washing unit, a methanol synthesis unit, and a desorption unit connected in series. The fluidized bed is connected to the pyrolysis furnace to receive the pyrolysis char and gasify it to produce crude synthesis gas. The crude synthesis gas is first cooled by the waste heat boiler, then the ratio of hydrogen to carbon monoxide in it is adjusted by the conversion system, and finally the acidic gases are washed out by the low-temperature methanol washing unit, and hydrogen and carbon monoxide are output. The hydrogen and carbon monoxide output from the low-temperature methanol washing unit enter the methanol synthesis unit to synthesize methanol. The acidic gases output from the low-temperature methanol washing unit are desorbed by the desorption unit to produce carbon dioxide, which is used in the production system of ammonium carbamate.

[0005] The polygeneration system of ammonium carbamate and biomass coupled gasification in this invention couples three major systems: pyrolysis, boiler, and gasification. The ammonia gas generated from the pyrolysis of biomass and ammonium carbamate is used for denitrification in the boiler. Simultaneously, the flue gas and pyrolysis gas generated in the pyrolysis furnace are fed into the boiler, creating a fuel-rich, oxygen-deficient atmosphere within the furnace, reducing NOx formation at the source. Furthermore, the gasification system ensures full utilization of materials throughout the system, especially the heat, gaseous substances, and solid substances generated by the biomass.

[0006] In some embodiments, the denitrification agent processing unit includes a denitrification agent silo, a conveying pipeline, a blower, a cyclone separator, and a metering conveyor. The denitrification agent silo is used to store solid ammonium carbamate. The blower is connected to the conveying pipeline, and the outlet of the denitrification agent silo is connected to the conveying pipeline. The fluidized airflow output by the blower mixes with the ammonium carbamate falling from the denitrification agent silo to form fluidized material, which is then conveyed along the conveying pipeline. The inlet of the cyclone separator is connected to the end of the conveying pipeline. The cyclone separator is used to receive the mixed raw material medium conveyed by the conveying pipeline and separate it into qualified granular ammonium carbamate and dust medium. The inlet of the metering conveyor is connected to the bottom outlet of the cyclone separator, and the outlet of the metering conveyor is connected to the pyrolysis furnace. The metering conveyor is used to receive the ammonium carbamate output by the cyclone separator and meterly convey it to the pyrolysis furnace.

[0007] In some embodiments, the denitrification agent treatment unit further includes a gas-solid separator. The inlet of the gas-solid separator is connected to the cyclone separator and is used to receive the dust medium. The gaseous medium outlet of the gas-solid separator is connected to the boiler body, and the solid medium outlet is connected to the denitrification agent silo. The gas-solid separator is used for gas-solid separation of the dust medium and outputs solid ammonium carbamate and gaseous mixed medium. The gaseous mixed medium is transported to the boiler body for boiler combustion and denitrification, and the solid ammonium carbamate is transported to the denitrification agent silo.

[0008] In some embodiments, the pyrolysis furnace includes a shell, an insulation layer, a first stirring shaft, a second stirring shaft, and a heater. A pyrolysis chamber is formed inside the shell. The insulation layer covers the outer wall of the shell, and a heating chamber is formed between the insulation layer and the outer wall of the shell. The heating chamber is used to supply a first heat-conducting medium. The first stirring shaft and the second stirring shaft are hollow shafts that rotate synchronously in opposite directions. The axes of the first stirring shaft and the second stirring shaft are parallel. The outer walls of the first stirring shaft and the second stirring shaft are provided with helical blades with opposite rotation directions to achieve stirring and propulsion. The heater includes a first heating tube rotatably disposed inside the first stirring shaft and a second heating tube rotatably disposed inside the second stirring shaft.

[0009] In some embodiments, the heater is a U-shaped tube structure comprising two straight pipe sections and a U-shaped section. The two straight pipe sections respectively form a first heating tube and a second heating tube. The heater includes a first partition, a second partition, an inlet pipe, and an outlet pipe. The first partition is a U-shaped plate adapted to the U-shaped tube structure and disposed inside the U-shaped tube structure. The first partition divides the pipe chamber inside the U-shaped tube into an interconnected inner channel and an outer channel. The second partition is disposed in the middle of the outer channel and separates the outer channel. An inlet side and an outlet side are formed on both sides of the second partition in the outer channel. The inlet pipe and the outlet pipe are respectively connected to the inlet side and the outlet side, so that the second heat-conducting medium enters through the inlet pipe, circulates through the outer channel and the inner channel, and is discharged through the outlet pipe.

[0010] In some embodiments, both the first heat-conducting medium and the second heat-conducting medium are selected from hot flue gas at 500℃-600℃, or both are selected from heat-conducting oil at 300℃-400℃.

[0011] In some embodiments, the pyrolysis reaction temperature of the pyrolysis furnace is 250℃-350℃, and the pyrolysis reaction time is 10s-20s.

[0012] In some embodiments, the biomass material located in the biomass silo has a particle size of less than 3 cm and a moisture content of less than 20%.

[0013] In some embodiments, the temperature of the crude syngas produced by the fluidized bed is greater than or equal to 1200°C, and the temperature of the crude syngas after being cooled by the waste heat boiler is 200°C-300°C.

[0014] In some embodiments, solid ammonium carbamate is in granular form.

[0015] In some embodiments, the molar ratio of hydrogen to carbon monoxide in the crude syngas adjusted by the conversion system is 2.05:1-2.2:1.

[0016] In some embodiments, the polygeneration system of ammonium carbamate coupled with biomass gasification further includes a crusher, which is located between the pyrolysis furnace and the fluidized bed. The crusher's feed inlet is connected to the solid phase outlet of the pyrolysis furnace, and its discharge outlet is connected to the feed inlet of the fluidized bed. The crusher is used to receive the pyrolysis char produced by the pyrolysis furnace, crush it, and then transport it to the fluidized bed.

[0017] In this invention, the pyrolysis char produced by the pyrolysis furnace of the polygeneration system for co-generation of ammonium carbamate and biomass is converted into green methanol via the gasification system. Simultaneously, high-purity green CO2 is produced as a byproduct, which can be directly reused to produce more ammonium carbamate, forming a closed-loop carbon resource cycle. The entire system achieves cascade utilization of biomass materials, simultaneously completing low-NOx and low-carbon combustion in the boiler and the co-production of green chemicals. While meeting ultra-low emission requirements, it reduces operating costs and significantly improves the utilization efficiency of biomass resources. Attached Figure Description

[0018] Fig. 1 This is an overall schematic diagram of the present invention.

[0019] Fig. 2 This is a cross-sectional schematic diagram of a pyrolysis furnace.

[0020] Fig. 3 This is a schematic diagram of the heater.

[0021] Figure label:

[0022] 1. Pyrolysis system; 2. Boiler system; 21. Boiler body; 3. Gasification system; 4. Crusher; 11. Pyrolysis furnace; 111. Shell; 112. Insulation layer; 113. First stirring shaft; 114. Second stirring shaft; 115. Spiral blade; 116. Heater; 1161. First partition; 1162. Second partition; 1163. Liquid inlet pipe; 1164. Liquid outlet pipe; 12. Biomass feed silos; 13. Denitrification agent processing unit; 131. Denitrification agent silo; 132. Conveying pipeline; 133. Fan; 134. Cyclone separator; 135. Quantitative conveyor; 136. Gas-solid separator; 31. Fluidized bed; 32. Waste heat boiler; 33. Shift conversion system; 34. Low-temperature methanol washing unit; 35. Methanol synthesis unit; 36. Desorption unit. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] like Figs. 1-3As shown, the polygeneration system of ammonium carbamate and biomass coupled gasification according to an embodiment of the present invention includes a pyrolysis system 1, a boiler system 2, and a gasification system 3. The pyrolysis system 1 includes a pyrolysis furnace 11, a biomass silo 12 connected to the pyrolysis furnace 11, and a denitrification agent treatment unit 13. The denitrification agent treatment unit 13 is used to feed solid ammonium carbamate to the pyrolysis furnace 11. The biomass silo 12 is used to provide biomass material to the pyrolysis furnace 11. The pyrolysis furnace 11 is used to pyrolyze the ammonium carbamate and biomass material to generate flue gas, pyrolysis gas, and pyrolysis char. The boiler system 2 includes a boiler body 21, which is connected to the gas phase outlet of the pyrolysis furnace 11 and is used to receive flue gas and pyrolysis gas for denitrification of the boiler body 21. The gasification system 3 includes, in sequence, a boiler body 21 connected to the gas phase outlet of the pyrolysis furnace 11 and used to receive flue gas and pyrolysis gas for denitrification of the boiler body 21. The system consists of a fluidized bed 31, a waste heat boiler 32, a conversion system 33, a low-temperature methanol washing unit 34, a methanol synthesis unit 35, and a desorption unit 36 ​​connected in series. The fluidized bed 31 is connected to the pyrolysis furnace 11 to receive pyrolysis char and gasify it to produce crude synthesis gas. The crude synthesis gas is first cooled by the waste heat boiler 32, then the ratio of hydrogen and carbon monoxide in it is adjusted by the conversion system 33, and finally the acidic gas is washed out by the low-temperature methanol washing unit 34, and hydrogen and carbon monoxide are output. The hydrogen and carbon monoxide output by the low-temperature methanol washing unit 34 enter the methanol synthesis unit 35 to synthesize methanol. The acidic gas output by the low-temperature methanol washing unit 34 is desorbed by the desorption unit 36 ​​to produce carbon dioxide, which is used in the production system of ammonium carbamate.

[0025] The polygeneration system of ammonium carbamate and biomass coupled gasification in this invention can simultaneously achieve efficient thermochemical conversion of biomass and low-NOx and low-carbon combustion of coal-fired boilers, solving the problems of high ammonia escape risk, high operating energy consumption and many by-products in traditional flue gas denitrification processes. At the same time, through the coupling of multiple process links, green methanol and green ammonium carbamate are co-produced, forming a carbon resource recycling system and reducing the overall carbon emissions and operating costs of the system.

[0026] The system of the present invention consists of three parts: a pyrolysis system 1, a boiler system 2, and a gasification system 3. The pyrolysis system 1 is connected to the boiler system 2 and the gasification system 3 respectively. The boiler system 2 receives the gaseous products of the pyrolysis system 1, and the gasification system 3 receives the solid products of the pyrolysis system 1. The three systems work together to complete the entire continuous production process from raw material input to multi-product output.

[0027] In pyrolysis system 1, the biomass silo 12 is directly connected to the pyrolysis furnace 11, allowing for a continuous and stable supply of biomass materials. The denitrification agent treatment unit 13 is also connected to the pyrolysis furnace 11, supplying solid ammonium carbamate into it. The pyrolysis furnace 11 serves as the core carrier for the co-pyrolysis reaction. After receiving the biomass materials and ammonium carbamate, it completes the co-pyrolysis process of the two materials under set reaction conditions, simultaneously producing three types of products: flue gas, pyrolysis gas, and pyrolysis char.

[0028] In boiler system 2, the boiler body 21 is directly connected to the gas phase outlet of the pyrolysis furnace 11. The flue gas and pyrolysis gas generated by co-pyrolysis in the pyrolysis furnace 11 are transported to the interior of the boiler body 21 through the gas phase outlet. After the flue gas and pyrolysis gas enter the boiler body 21, a locally fuel-rich and oxygen-poor atmosphere can be formed in the combustion zone, inhibiting the formation of nitrogen oxides during boiler combustion. At the same time, the reducing component (NH3) in the pyrolysis gas can directly participate in the denitrification reaction of the boiler flue gas, reducing the original emission concentration of nitrogen oxides at the boiler outlet. The combustible components in the pyrolysis gas can simultaneously participate in the boiler combustion heat release, reducing the consumption of fossil fuels in the boiler and reducing carbon emissions during boiler operation. Among them, solid ammonium carbamate can be decomposed into ammonia and carbon dioxide in one step. The reaction process is more concise.

[0029] In the gasification system 3, the feed end of the fluidized bed 31 is connected to the solid phase outlet of the pyrolysis furnace 11, receiving the pyrolytic carbon produced by co-pyrolysis in the pyrolysis furnace 11. The pyrolytic carbon undergoes a high-temperature gasification reaction within the fluidized bed 31 to generate crude syngas. The crude syngas produced by the fluidized bed 31 first enters the waste heat boiler 32, where heat exchange and cooling are performed. The cooled crude syngas then enters the conversion system 33, where the ratio of hydrogen to carbon monoxide is adjusted. The crude syngas with the adjusted ratio enters the low-temperature methanol washing unit 34, where acidic gases are removed, and hydrogen and carbon monoxide meeting the synthesis requirements are output. The hydrogen and carbon monoxide output from the low-temperature methanol washing unit 34 directly enter the methanol synthesis unit 35 to complete the synthesis and preparation of green methanol. The acidic gas removed by the low-temperature methanol washing unit 34 enters the analysis unit 36. The analysis unit 36 ​​performs stepwise analysis of the acidic gas to produce high-purity carbon dioxide. This carbon dioxide is directly transported to the ammonium carbamate production system for the preparation of green ammonium carbamate, realizing the closed-loop recycling of carbon resources within the system.

[0030] In some embodiments, the denitrification agent processing unit 13 includes a denitrification agent silo 131, a conveying pipeline 132, a blower 133, a cyclone separator 134, and a metering conveyor 135. The denitrification agent silo 131 is used to store solid ammonium carbamate. The blower 133 is connected to the conveying pipeline 132, and the outlet of the denitrification agent silo 131 is connected to the conveying pipeline 132. The fluidized airflow output by the blower 133 mixes with the ammonium carbamate falling from the denitrification agent silo 131 to form fluidized material, which then flows along the conveying pipeline 132. The inlet of the cyclone separator 134 is connected to the end of the conveying pipe 132. The cyclone separator 134 is used to receive the mixed raw material medium conveyed by the conveying pipe 132 and separate it into qualified granular ammonium carbamate and dust medium. The inlet of the metering conveyor 135 is connected to the bottom outlet of the cyclone separator 134. The outlet of the metering conveyor 135 is connected to the pyrolysis furnace 11. The metering conveyor 135 is used to receive the ammonium carbamate output from the cyclone separator 134 and meter it into the pyrolysis furnace 11.

[0031] This embodiment can realize continuous fluidized conveying, particle classification and precise quantitative feeding of solid ammonium carbamate, effectively avoiding blockage and feeding fluctuation problems during the solid denitrification agent conveying process, and ensuring the stable and controllable feed amount of denitrification agent in pyrolysis furnace 11.

[0032] The denitrification agent silo 131 is used to store pretreated solid ammonium carbamate, which is usually in granular form. The outlet of the denitrification agent silo 131 is connected to the conveying pipe 132, allowing the stored ammonium carbamate to continuously fall into the conveying pipe 132. The blower 133 is connected to the front end of the conveying pipe 132, and the blower 133 continuously outputs a fluidizing airflow. The fluidizing airflow is fully mixed with the falling ammonium carbamate in the conveying pipe 132 to form a uniform fluidized material, which is continuously conveyed to the end of the conveying pipe 132.

[0033] The inlet of the cyclone separator 134 is directly connected to the end of the conveying pipe 132. After receiving the fluidized material conveyed by the conveying pipe 132, the cyclone separator 134 performs material classification through centrifugal separation, separating the fluidized material into qualified granular ammonium carbamate and a dust medium carrying fine powdered ammonium carbamate. The qualified granular ammonium carbamate collects at the bottom outlet of the cyclone separator 134 under gravity, while the dust medium is discharged from the top outlet of the cyclone separator 134.

[0034] The inlet of the quantitative conveyor 135 is connected to the bottom outlet of the cyclone separator 134, and the outlet of the quantitative conveyor 135 is directly connected to the pyrolysis furnace 11. The quantitative conveyor 135 receives qualified granular ammonium carbamate output from the bottom of the cyclone separator 134 and continuously and stably conveys the ammonium carbamate into the pyrolysis furnace 11 according to the preset feed parameters.

[0035] In some embodiments, the denitrification agent treatment unit 13 further includes a gas-solid separator 136. The inlet of the gas-solid separator 136 is connected to the cyclone separator 134 and is used to receive dust media. The gaseous media outlet of the gas-solid separator 136 is connected to the boiler body 21, and the solid media outlet is connected to the denitrification agent silo 131. The gas-solid separator 136 is used for gas-solid separation of dust media and outputs solid ammonium carbamate and gaseous mixed media. The gaseous mixed media is transported to the boiler body 21 for boiler combustion and denitrification, and the solid ammonium carbamate is transported to the denitrification agent silo 131.

[0036] This embodiment allows for secondary separation of the dust medium containing fine ammonium carbamate discharged from the cyclone separator 134, efficiently recovering the entrained fine ammonium carbamate, reducing the transport loss of denitrification agent raw materials, and improving raw material utilization. Simultaneously, the separated gaseous mixture is directly reused in the boiler system 2, realizing the resource utilization of the transport air, while avoiding material waste and ammonia escape risks caused by the discharge of fine powder with the transport air, further enhancing the boiler denitrification effect and the environmental friendliness of the system operation.

[0037] Specifically, the gas-solid separator 136 employs a bag filter, electrostatic precipitator, or cyclone separator 134 to meet separation requirements. The gaseous mixed medium produced is directly transported to the boiler body 21 through the gaseous medium outlet of the gas-solid separator 136, serving as secondary air for the boiler's combustion and denitrification processes. Trace amounts of ammonium carbamate remaining in the gaseous mixed medium can undergo pyrolysis at the boiler's high-temperature environment, releasing ammonia that directly participates in the denitrification reaction of the boiler flue gas, further reducing the concentration of nitrogen oxide emissions from the boiler; simultaneously, the air component in the gaseous mixed medium can supplement the combustion air required for boiler combustion.

[0038] In some embodiments, the pyrolysis furnace 11 includes a shell 111, an insulation layer 112, a first stirring shaft 113, a second stirring shaft 114, and a heater 116. A pyrolysis chamber is formed inside the shell 111. The insulation layer 112 covers the outer wall of the shell 111, and a heating chamber is formed between the insulation layer 112 and the outer wall of the shell 111. The heating chamber is used to supply the flow of a first heat-conducting medium. The first stirring shaft 113 and the second stirring shaft 114 are hollow shafts that rotate synchronously in opposite directions. The axes of the first stirring shaft 113 and the second stirring shaft 114 are parallel. The outer walls of the first stirring shaft 113 and the second stirring shaft 114 are provided with helical blades 115 that rotate in opposite directions to achieve stirring and propulsion. The heater 116 includes a first heating tube rotatably disposed in the first stirring shaft 113 and a second heating tube rotatably disposed in the second stirring shaft 114.

[0039] In some embodiments, the heater 116 has a U-shaped tube structure and includes two straight pipe sections and a U-shaped section. The two straight pipe sections respectively form a first heating tube and a second heating tube. The heater 116 includes a first partition 1161, a second partition 1162, an inlet pipe 1163, and an outlet pipe 1164. The first partition 1161 is a U-shaped plate adapted to the U-shaped tube structure and is disposed inside the U-shaped tube structure. The first partition 1161 divides the pipe chamber inside the U-shaped tube into an interconnected inner channel and an outer channel. The second partition 1162 is disposed in the middle of the outer channel and divides the outer channel. An inlet side and an outlet side are formed on both sides of the second partition 1162 in the outer channel. The inlet pipe 1163 and the outlet pipe 1164 are connected to the inlet side and the outlet side, respectively, so that the second heat transfer medium enters through the inlet pipe 1163, circulates through the outer channel and the inner channel, and is discharged through the outlet pipe 1164.

[0040] This embodiment utilizes a dual-layer synchronous heating structure—combining outer chamber heating and inner shaft heating—along with a dual-shaft counter-stirring propulsion structure, to achieve precise temperature control within the pyrolysis chamber and uniform heating of the material throughout the process. This effectively avoids localized overheating or incomplete pyrolysis, ensuring the stable pyrolysis of ammonium carbamate and biomass. Simultaneously, the optimized flow channel design within heater 116 standardizes the flow path of the heat-conducting medium, improving the temperature uniformity of the first stirring shaft 113 and the second stirring shaft 114.

[0041] The shell 111 contains a closed pyrolysis chamber, which provides a sealed reaction space for the co-pyrolysis reaction of ammonium carbamate and biomass.

[0042] The heating chamber provides a continuous flow channel for the first heat-conducting medium. During the continuous flow of the first heat-conducting medium in the heating chamber, it typically enters from the bottom and exits from the top to improve the heat transfer to the pyrolysis chamber and achieve uniform heating of the outer layer of the pyrolysis chamber. The insulation layer 112 can effectively prevent heat loss to the outside.

[0043] The first stirring shaft 113 and the second stirring shaft 114 are installed parallel to each other inside the pyrolysis chamber. Both the first stirring shaft 113 and the second stirring shaft 114 are hollow rotating shafts, driven by a drive mechanism to achieve synchronous counter-rotation. Spiral blades 115 are fixed to the outer walls of both the first stirring shaft 113 and the second stirring shaft 114, with the corresponding spiral blades 115 rotating in opposite directions. When the first stirring shaft 113 and the second stirring shaft 114 rotate synchronously in opposite directions, the spiral blades 115 rotating in opposite directions can drive the ammonium carbamate and biomass materials in the pyrolysis chamber to synchronously complete radial stirring and axial uniform propulsion, ensuring full contact and fusion of the two materials. This avoids the problems of uneven decomposition and caking of ammonium carbamate due to local overheating, ensuring the stable and continuous progress of the co-pyrolysis reaction. The pyrolysis furnace 11 ultimately achieves the effects of heating, stirring, and conveying. Typically, the shell 111 is equipped with dedicated outlets for gaseous and solid substances to discharge pyrolysis gas (including flue gas) and pyrolysis char, respectively.

[0044] The heater 116 adopts a U-shaped tube structure, consisting of two straight tube sections and one U-shaped section. The two straight tube sections respectively form the first heating tube and the second heating tube. The first heating tube is rotatably mounted in the hollow cavity of the first stirring shaft 113 via a bearing, and the depth to which the first heating tube is inserted into the first stirring shaft 113 is generally as long as possible. The second heating tube is similarly designed.

[0045] The heater 116 also has a first partition 1161 inside its U-shaped tube structure. The first partition 1161 is a U-shaped plate adapted to the U-shaped tube structure and is completely embedded inside the U-shaped tube structure, dividing the pipe chamber inside the U-shaped tube into an interconnected inner channel and an outer channel. The inner channel and the outer channel are connected at the end of the U-shaped section. A second partition 1162 is provided in the middle of the outer channel, which completely separates the outer channel, so that independent liquid inlet and liquid outlet sides are formed on both sides of the second partition 1162.

[0046] The second heat transfer medium enters the inlet side of the heater 116 through the inlet pipe 1163, flows along the outer channel towards the U-shaped section, enters the inner channel through the through-hole at the end of the U-shaped section, then flows in the reverse direction along the inner channel, and flows through the outer channel again before finally being discharged through the outlet pipe 1164, forming a complete circulating flow path. This flow channel design ensures uniform heat exchange between the first and second heating tubes throughout the entire process.

[0047] In some embodiments, the first and second heat transfer media can be the same heat exchange medium, such as hot flue gas at 500℃-600℃ or heat transfer oil at 300℃-400℃. Through the synergistic effect of internal and external double-layer heating, the pyrolysis reaction temperature within the pyrolysis chamber can be stably controlled within the range of 250℃-350℃. Simultaneously, with the propulsion speed of the twin-shaft stirring, the residence time of the material within the pyrolysis chamber is controlled to 10s-20s, fully meeting the operating requirements of one-step pyrolysis of ammonium carbamate to produce ammonia and biomass pyrolysis. The ratio of the processing capacity of the pyrolysis system 1 to the capacity of the boiler body 21 is controlled between 2-10 kg / MJ, that is, when the processing capacity of the pyrolysis system 1 is 200-1000 kg / h, the boiler capacity is 100MW.

[0048] In some embodiments, the polygeneration system of ammonium carbamate coupled with biomass gasification further includes a crusher 4, which is located between the pyrolysis furnace 11 and the fluidized bed 31. The feed inlet of the crusher 4 is connected to the solid phase outlet of the pyrolysis furnace 11, and the discharge outlet of the crusher 4 is connected to the feed inlet of the fluidized bed 31. It is used to receive the pyrolysis char produced by the pyrolysis furnace 11, crush it, and then transport it to the fluidized bed 31.

[0049] In this embodiment, a crusher 4 is installed between the pyrolysis furnace 11 and the airflow bed 31. The feed inlet of the crusher 4 is sealed to the solid phase outlet of the pyrolysis furnace 11, and the discharge outlet of the crusher 4 is sealed to the feed inlet of the airflow bed 31, forming a fully enclosed continuous conveying channel for pyrolysis char from production, crushing to gasification feeding. The entire process isolates the outside air, avoiding oxidation and burn-off of pyrolysis char due to contact with oxygen, and at the same time preventing material waste and environmental pollution caused by the overflow of pyrolysis char dust.

[0050] The pyrolytic carbon produced by the co-pyrolysis reaction in the pyrolysis furnace 11 is continuously discharged through the solid phase outlet of the pyrolysis furnace 11 and directly fed into the crusher 4 through a closed pipeline. The crusher 4 performs step-by-step crushing and grinding on the incoming pyrolytic carbon, crushing it into powder with a particle size of less than 0.15 mm, which perfectly matches the feed particle size requirements of the gasification in the fluidized bed 31, ensuring that all pyrolytic carbon materials can meet the particle size standard required for the gasification reaction.

[0051] The qualified pyrolytic char powder, after being crushed, is continuously discharged from the outlet of crusher 4 and directly and stably conveyed to the inlet of fluidized bed 31 through a closed conveying mechanism, where it enters the fluidized bed 31 to participate in the high-temperature gasification reaction. The uniform particle size of the powder allows the pyrolytic char to react fully within the fluidized bed 31.

[0052] In some embodiments, the biomass material located in the biomass silo 12 has a particle size of less than 3 cm and a moisture content of less than 20%. Typically, the biomass material is crushed and dried to meet the requirements for particle size and moisture content.

[0053] In some embodiments, solid ammonium carbamate is granular with a uniform particle size, typically 3 mm or less. As a novel denitrification agent, it is less prone to escape compared to traditional liquid ammonia. It is easy to transport and has a good denitrification effect.

[0054] In some embodiments, the temperature of the crude syngas produced by the fluidized bed 31 is greater than or equal to 1200°C, and the temperature of the crude syngas after being cooled by the waste heat boiler 32 is 200°C-300°C. The molar ratio of hydrogen to carbon monoxide in the crude syngas after being adjusted by the conversion system 33 is 2.05:1-2.2:1.

[0055] The following describes the gasification system 3 of this embodiment. Upstream of the gasification system 3, it is connected to the solid phase outlet of the pyrolysis furnace 11 of the pyrolysis system 1 via the crusher 4. Downstream, it is connected to the methanol product collection system and the ammonium carbamate production system, respectively. The entire process adopts a closed continuous operation mode, which isolates the outside air from entering, avoids material oxidation loss and dust overflow, and ensures the environmental protection and material conversion rate of the production process.

[0056] The fluidized bed 31 receives the crushed pyrolytic carbon powder. The pyrolytic carbon powder and the gasifying agent are mixed at high speed and in full contact within the fluidized bed 31, undergoing a rapid gasification reaction under high temperature and high pressure, realizing the complete conversion of fixed carbon and volatile matter in the pyrolytic carbon, and producing high-temperature crude syngas with a temperature of not less than 1200℃. The main components of the high-temperature crude syngas are hydrogen, carbon monoxide, and carbon dioxide, and it also contains small amounts of hydrogen sulfide, dust, and tar impurities. The crude syngas is continuously discharged through the gas phase outlet at the top of the fluidized bed 31 and directly transported to the waste heat boiler 32.

[0057] Waste heat boiler 32 receives high-temperature crude syngas from fluidized bed 31. Within waste heat boiler 32, the high-temperature crude syngas undergoes heat exchange and cooling, waste heat recovery, and water washing purification treatment sequentially. The high-temperature crude syngas fully exchanges heat with the heat exchange medium within waste heat boiler 32, recovering high-temperature waste heat to produce saturated steam. This steam can be directly used in the system's shift reaction, material heating, and other processes, reducing the overall external energy consumption of the system. Simultaneously, the crude syngas undergoes water washing after heat exchange to remove entrained solid dust, tar, and other impurities. Finally, the temperature of the crude syngas is stably reduced to 200℃-300℃, and it is then transported to the shift system 33 via a closed pipeline.

[0058] The conversion system 33 receives the crude syngas cooled and purified by the waste heat boiler 32. Some of the carbon monoxide in the crude syngas undergoes a conversion reaction with the water vapor supplied by the system to generate hydrogen and carbon dioxide (CO + H2O - H2 + CO2). The system adjusts the reaction depth according to the initial composition of the crude syngas, and finally stabilizes the molar ratio of hydrogen to carbon monoxide in the crude syngas to 2.05:1-2.2:1, which fully matches the stoichiometric ratio requirements of the methanol synthesis reaction. The crude syngas with the hydrogen-carbon ratio adjusted is directly delivered to the low-temperature methanol washing unit 34.

[0059] The low-temperature methanol washing unit 34 receives the crude synthesis gas after the hydrogen-to-carbon ratio has been adjusted. Using low-temperature methanol as a selective absorbent, it selectively adsorbs and removes acidic gases such as carbon dioxide and hydrogen sulfide from the crude synthesis gas under low-temperature and high-pressure conditions, completing the deep purification of the crude synthesis gas. The purified synthesis gas mainly consists of hydrogen and carbon monoxide, and its purity fully meets the feed requirements for methanol synthesis. It is directly fed to the methanol synthesis unit 35. The saturated methanol-rich solution is discharged from the bottom of the low-temperature methanol washing unit 34 and directly fed to the desorption unit 36.

[0060] The analysis unit 36 ​​receives the methanol-rich solution output from the low-temperature methanol washing unit 34 and performs stepwise analysis of the acidic gases in the methanol-rich solution through a process of progressively reducing pressure and gradually increasing temperature. During the analysis, high-purity hydrogen sulfide gas is first separated and collected for harmless treatment to avoid environmental pollution. Subsequently, high-purity carbon dioxide gas is analyzed stepwise. The green carbon dioxide, derived from biomass conversion, has a purity of up to 99.9% and contains no harmful impurities. It can be directly transported to the ammonium carbamate production system as a core raw material for the preparation of green ammonium carbamate, achieving closed-loop recycling of carbon resources within the system. The methanol solution after analysis is cooled and then returned to the low-temperature methanol washing unit 34 for reuse, reducing reagent consumption during system operation.

[0061] The methanol synthesis unit 35 receives purified hydrogen and carbon monoxide from the low-temperature methanol washing unit 34. Under set temperature and pressure conditions and with the aid of a dedicated catalyst, the hydrogen and carbon monoxide undergo a methanol synthesis reaction to produce green methanol. This completes the conversion of biomass into a high-value-added liquid product, achieving the system's multi-product objective.

[0062] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0065] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0066] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0067] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A polygeneration system for the coupled gasification of ammonium carbamate and biomass, characterized in that, include: A pyrolysis system, comprising a pyrolysis furnace, a biomass silo connected to the pyrolysis furnace, and a denitrification agent treatment unit, wherein the denitrification agent treatment unit is used to feed solid ammonium carbamate to the pyrolysis furnace, the biomass silo is used to supply biomass material to the pyrolysis furnace, and the pyrolysis furnace is used to pyrolyze the ammonium carbamate and the biomass material to generate flue gas, pyrolysis gas, and pyrolysis char. A boiler system, comprising a boiler body connected to the gas phase outlet of the pyrolysis furnace and used to receive the flue gas and the pyrolysis gas for denitrification of the boiler body; The gasification system comprises a fluidized bed, a waste heat boiler, a shift conversion system, a low-temperature methanol washing unit, a methanol synthesis unit, and a desorption unit connected in series. The fluidized bed is connected to the pyrolysis furnace to receive the pyrolysis char and gasify it to produce crude syngas. The crude syngas is first cooled by the waste heat boiler, then the ratio of hydrogen to carbon monoxide in it is adjusted by the shift conversion system, and finally the acidic gases are washed out by the low-temperature methanol washing unit, and hydrogen and carbon monoxide are output. The hydrogen and carbon monoxide output from the low-temperature methanol washing unit enter the methanol synthesis unit to synthesize methanol. The acidic gases output from the low-temperature methanol washing unit are desorbed by the desorption unit to produce carbon dioxide, which is used in the production system of ammonium carbamate.

2. The polygeneration system for co-gasification of ammonium carbamate and biomass according to claim 1, characterized in that, The denitrification agent treatment unit includes: Denitrification agent silo, used to store solid ammonium carbamate; The system includes a conveying pipeline and a blower. The blower is connected to the conveying pipeline, and the outlet of the denitrification agent silo is connected to the conveying pipeline. The fluidized airflow output by the blower mixes with the ammonium carbamate falling from the denitrification agent silo to form fluidized material, which is then conveyed along the conveying pipeline. A cyclone separator, the inlet of which is connected to the end of the conveying pipeline, is used to receive the mixed raw material medium conveyed by the conveying pipeline and separate it into qualified granular ammonium carbamate and dust medium. A quantitative conveyor is provided, the inlet of which is connected to the bottom outlet of the cyclone separator, and the outlet of which is connected to the pyrolysis furnace. The quantitative conveyor is used to receive ammonium carbamate output from the cyclone separator and quantitatively convey it to the pyrolysis furnace.

3. The polygeneration system for co-gasification of ammonium carbamate and biomass according to claim 2, characterized in that, The denitrification agent treatment unit also includes a gas-solid separator. The inlet of the gas-solid separator is connected to the cyclone separator and is used to receive the dust medium. The gaseous medium outlet of the gas-solid separator is connected to the boiler body, and the solid medium outlet is connected to the denitrification agent silo. The gas-solid separator is used for gas-solid separation of the dust medium and outputs solid ammonium carbamate and gaseous mixed medium. The gaseous mixed medium is transported to the boiler body for boiler combustion and denitrification, and the solid ammonium carbamate is transported to the denitrification agent silo.

4. The polygeneration system for co-gasification of ammonium carbamate and biomass according to claim 1, characterized in that, The pyrolysis furnace includes: A shell, within which a pyrolysis chamber is formed. A thermal insulation layer is provided, which covers the outer wall of the shell. The thermal insulation layer and the outer wall of the shell enclose a heating chamber for the flow of a first heat-conducting medium. The first stirring shaft and the second stirring shaft are hollow shafts that rotate synchronously in opposite directions. The axes of the first stirring shaft and the second stirring shaft are parallel. The outer walls of the first stirring shaft and the second stirring shaft are provided with spiral blades with opposite directions of rotation to achieve tumbling and propulsion. The heater includes a first heating tube rotatably disposed within the first stirring shaft and a second heating tube rotatably disposed within the second stirring shaft.

5. The polygeneration system for co-gasification of ammonium carbamate and biomass according to claim 4, characterized in that, The heater has a U-shaped tube structure and includes two straight tube sections and one U-section. The two straight tube sections respectively form a first heating tube and a second heating tube. The heater includes: The first partition is a U-shaped plate adapted to the U-shaped tube structure and disposed inside the U-shaped tube structure. The first partition divides the pipe chamber inside the U-shaped tube into an interconnected inner channel and an outer channel. The second partition is located in the middle of the outer channel and separates the outer channel. The outer channel has an inlet side and an outlet side on both sides of the second partition. The liquid inlet pipe and the liquid outlet pipe are respectively connected to the liquid inlet side and the liquid outlet side, so that the second heat transfer medium enters through the liquid inlet pipe, circulates through the outer channel and the inner channel, and is discharged through the liquid outlet pipe.

6. The polygeneration system for co-gasification of ammonium carbamate and biomass according to claim 5, characterized in that, Both the first heat-conducting medium and the second heat-conducting medium are selected from hot flue gas at 500℃-600℃, or both are selected from heat-conducting oil at 300℃-400℃. The pyrolysis reaction temperature of the pyrolysis furnace is 250℃-350℃, and the pyrolysis reaction time is 10s-20s.

7. The polygeneration system for co-gasification of ammonium carbamate and biomass according to claim 1, characterized in that, The biomass material located in the biomass silo has a particle size of less than 3 cm and a moisture content of less than 20%.

8. The polygeneration system for co-gasification of ammonium carbamate and biomass according to claim 1, characterized in that, The temperature of the crude syngas produced by the fluidized bed is greater than or equal to 1200℃, and the temperature of the crude syngas after being cooled by the waste heat boiler is 200℃-300℃.

9. The polygeneration system for co-gasification of ammonium carbamate and biomass according to any one of claims 1-8, characterized in that, Solid ammonium carbamate is in granular form; The molar ratio of hydrogen to carbon monoxide in the crude syngas after adjustment by the aforementioned conversion system is 2.05:1-2.2:

1.

10. The polygeneration system for co-gasification of ammonium carbamate and biomass according to claim 9, characterized in that, It also includes a crusher, which is located between the pyrolysis furnace and the fluidized bed. The inlet of the crusher is connected to the solid phase outlet of the pyrolysis furnace, and the outlet is connected to the inlet of the fluidized bed. It is used to receive the pyrolysis char produced by the pyrolysis furnace, crush it, and then transport it to the fluidized bed.

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