An efficient biomass dry powder pressurized entrained flow gasification process system

Abstract

The present invention discloses an efficient biomass dry powder pressurized entrained flow gasification process system. The process steps of this system include: after the biomass raw materials are made into dry powder by the biomass powder making unit, they are transported to the biomass gasification and heat recovery unit through the biomass transportation unit. The biomass powder reacts with steam and oxygen in the biomass gasification and heat recovery unit to generate syngas, heat is recovered, and coarse slag and fine ash are separated; the syngas after heat recovery enters the syngas purification unit to further remove fine ash and then is sent to the next process section for use; the slag water and black water enter the slag water treatment unit for treatment and then are reused; the steam-water system unit exchanges heat between the boiler feed water and the syngas and recovers heat, and high-pressure steam is generated in the steam-water system for external use after the heat is recovered. The biomass dry powder pressurized entrained flow gasification technical route of the present invention has the characteristics of high effective gas component, high cold gas efficiency, tar and methane-free syngas, and low operating cost, and can achieve better economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass resource gasification utilization, and particularly to a high-efficiency biomass dry powder pressurized entrained flow gasification process system. Background Art

[0002] Using biomass as a zero-carbon fuel to produce green chemicals has attracted wide attention. Especially the market demand for "green methanol". It is expected that the global demand for green methanol will exceed 30 million tons / year by 2030, and the market scale of green methanol is expected to reach 250 million tons in 2050. In December 2023, green methanol was also included in the plan of China's modern energy system to strengthen the demonstration application of green methanol in industries, transportation, power generation, construction, consumption and other fields. The bio-gasification to produce green methanol with biomass gasification as the source and the coupling of biomass gasification and green hydrogen to produce green methanol are currently the most suitable technical routes for large-scale production and have cost advantages, and are the absolute mainstream technical routes for the current development of green methanol. As a key common technology for green methanol, there is currently no mature and efficient biomass gasification technology for large-scale application. The advantages and disadvantages of bio-gasification technology are the main technical bottlenecks restricting the development of the green methanol industry.

[0003] At present, to meet the needs of chemical production, the research and application of biomass gasification technology are developing from atmospheric pressure gasification technology to pressurized gasification technology. The main biomass pressurized gasification technology routes under research or promotion are biomass fixed bed gasification technology, biomass fluidized bed gasification technology, and biomass entrained flow gasification technology. The synthesis gas produced by biomass fixed bed gasification technology has the disadvantage of difficult treatment of tar and methane. The synthesis gas produced by biomass fluidized bed gasification technology has less tar content, but there is still a large amount of methane in the synthesis gas, which is difficult to treat. Biomass fixed bed gasification technology and biomass fluidized bed gasification technology usually need to set a high-temperature reforming furnace behind the gasifier to treat the tar and methane in the synthesis gas, which leads to a significant increase in their investment costs, and there are also certain doubts about the operation stability and reliability of the high-temperature reforming furnace. The synthesis gas produced by biomass entrained flow gasification technology itself has the characteristics of almost no tar and methane, but the heat recovery problem of its high-temperature synthesis gas has not been well solved. Especially when the alkali metal content in biomass is high, it is easy to cause fouling of the heating surface of the waste heat boiler, resulting in low efficiency of the heat recovery equipment. Therefore, the present invention patent proposes a high-efficiency biomass dry powder pressurized entrained flow gasifier and process system, which can achieve efficient biomass gasification and full heat recovery, and will effectively contribute to the development of the green methanol industry with biomass gasification as the technical source. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention proposes an efficient biomass dry powder pressurized entrained flow gasification process system, which mainly solves a series of process problems in the biomass gasification process and is applied to the production of syngas from biomass. It can realize the process steps of biomass pulverization, biomass pneumatic conveying, biomass gasification, efficient heat recovery of syngas, syngas purification, and system slag water treatment, thereby efficiently preparing biomass into syngas and achieving efficient biomass pulverization and efficient heat recovery (anti-fouling) of syngas.

[0005] In order to achieve the above technical objectives, the following technical solutions are proposed:

[0006] An efficient biomass dry powder pressurized entrained flow gasification process system, characterized in that it includes a biomass pulverization unit, a biomass conveying unit, a biomass gasification and heat recovery unit, a syngas purification unit, a slag water treatment unit, and a steam-water system unit.

[0007] The gasification process flow of the gasification process system is as follows: Biomass raw materials are prepared into biomass dry powder through the biomass pulverization unit, and the biomass dry powder is sent to the biomass gasification and heat recovery unit by pneumatic conveying through the biomass conveying unit; the biomass powder reacts with steam and oxygen in the biomass gasification and heat recovery unit to generate syngas, and heat recovery is carried out to complete the separation of coarse slag and fine ash; the syngas after heat recovery enters the syngas purification unit to further remove the fine ash that has not been separated in the syngas and then is sent to the next process section for use; the slag water and black water in the process system enter the slag water treatment unit, and after steps of heat recovery, coarse slag separation, fine ash separation, ash water deoxidation, and ash water preheating in the slag water treatment unit, they enter the process system for reuse; in the steam-water system unit, boiler feed water is exchanged heat with the syngas and heat is recovered, and after heat recovery, high-pressure steam is generated in the steam-water system and sent out for use.

[0008] The biomass powder-making unit includes a material feed bin, a material conveyor, a material shredder, a shredded material conveyor, a material drying and powder-making device, a powder conveyor and corresponding pipelines; the feed inlet of the material feed bin is connected to the source of biomass raw materials, the discharge outlet of the material feed bin is connected to the feed end of the material conveyor, the discharge end of the material conveyor is connected to the feed inlet of the material shredder, the discharge outlet of the material shredder is connected to the feed end of the shredded material conveyor, the discharge end of the shredded material conveyor is connected to the feed inlet of the material drying and powder-making device, the discharge outlet of the material drying and powder-making device is connected to the feed end of the powder conveyor, and the discharge end of the powder conveyor is connected to the biomass conveying unit. The technological process of the biomass powder-making unit is as follows: the biomass raw materials first enter the material feed bin, and then are sent into the material shredder through the material conveyor to tear the biomass materials into shredded materials. The shredded materials are sent into the material drying and powder-making device through the shredded material conveyor. In the material drying and powder-making device, the shredded materials are simultaneously made into powder and dried. The particle size range of the biomass powder is 10μm - 200μm, and the moisture content of the biomass powder is controlled at 2% - 6%. The generated biomass dry powder is sent into the biomass conveying unit through the powder conveyor.

[0009] Furthermore, the material drying and powder-making device adopts a mechanical crushing method to prepare the biomass shredded materials into powder and simultaneously dry the biomass powder; for the drying, electric auxiliary heating, or steam auxiliary heating, or low-oxygen hot air drying is selected.

[0010] The biomass conveying unit includes a powder storage bin, a powder pressure-changing bin, a feeding bin and corresponding pipelines; the feed inlet of the powder storage bin is connected to the material pipeline connected to the discharge end of the powder conveyor, the discharge outlet of the powder storage bin is connected to the feed inlet of the powder pressure-changing bin, the discharge outlet of the powder pressure-changing bin is connected to the feed inlet of the feeding bin, and the discharge outlet of the feeding bin is connected to the biomass gasification and heat recovery unit. The technological process of the biomass conveying unit is as follows: the biomass dry powder from the biomass powder-making unit first enters the powder storage bin for standby. The biomass powder in the powder storage bin enters the feeding bin after being pressurized by the powder pressure-changing bin. After the materials in the powder pressure-changing bin are discharged into the feeding bin, they are depressurized and then the powder is added again for the next feeding into the feeding bin. The feeding bin continuously sends the biomass powder into the biomass gasification and heat recovery unit through the carrier gas by pneumatic conveying for gasification reaction. The powder pressure-changing bin can be set to one or more according to the actual situation.

[0011] Furthermore, the conveying carrier gas and pressurizing gas of the biomass conveying unit are inert gases CO2 or N2. Preferably, in the process of biomass gasification to produce green methanol, it is better to use CO2 as the conveying carrier gas and pressurizing gas.

[0012] The biomass gasification and heat recovery unit includes a burner, a gasification chamber of the gasifier, a slag gas treatment chamber of the gasifier, a slag breaker, a slag discharge lock hopper, a convection waste heat boiler, a recycle compressor, a steam-oxygen mixer, and corresponding pipelines. The burner, the gasification chamber of the gasifier, the slag gas treatment chamber of the gasifier, the slag breaker, and the slag discharge lock hopper are longitudinally arranged and connected in sequence. The slag gas treatment chamber of the gasifier is connected to the convection waste heat boiler through a gas transmission pipe. The syngas of the recycle compressor is connected to the slag gas treatment chamber of the gasifier in two paths. One steam output pipeline of the convection waste heat boiler is connected to the steam-oxygen mixer, and the mixed gas output pipeline of the steam-oxygen mixer is connected to the burner. The slag gas treatment chamber of the gasifier includes a radiant waste heat boiler in the upper and middle sections and a slag water bath section in the lower section. The radiant waste heat boiler is provided with a low-temperature syngas inlet purge line, a low-temperature syngas inlet cooling line, and a syngas discharge line.

[0013] One or more boiler feed water outlets are provided at the top of the shell of the radiant waste heat boiler, one or more boiler feed water inlets are provided at the lower end of the side wall of the shell, one or more air curtain gas inlets are installed at the upper end of the side wall of the shell. The heating surface of the radiant waste heat boiler is provided with multiple groups of annular air curtain soot blowing nozzles connected to the air curtain gas inlets in the vertical space. The jet gas velocity of the air curtain soot blowing nozzles is set between 15 and 45 m / s according to pressure matching. The air curtain soot blowing nozzles use low-temperature syngas from the recycle compressor to perform continuous or intermittent air curtain purging to ensure that the heating surface does not slag or accumulate ash. The air curtain gas inlet and multiple groups of air curtain soot blowing nozzles form a low-temperature syngas inlet purge line.

[0014] An impinging gas inlet and a boiler feed water inlet are installed at the lower part of the side wall of the shell of the radiant waste heat boiler. A syngas outlet is installed below the side wall below the impinging gas inlet and the boiler feed water inlet. An annular impinging gas nozzle is provided at the height corresponding to the impinging gas inlet in the radiant waste heat boiler, and a micro-cyclone annular gas collector is provided at the height corresponding to the syngas outlet. A number of micro-cyclone separators are evenly distributed at the lower end of the micro-cyclone annular gas collector. The impinging gas inlet and the annular impinging gas nozzle form a low-temperature syngas inlet cooling line, and the jet gas velocity of the impinging gas nozzle is set between 5 and 30 m / s. The micro-cyclone separators, the micro-cyclone annular gas collector, and the syngas outlet form a syngas discharge line.

[0015] Further, the burner has at least two or more process medium channels, and the burner has a water-cooling protection function.

[0016] Further, the gasification chamber of the gasifier and the slag gas treatment chamber of the gasifier can be integrally processed and manufactured, or can be separately processed and manufactured by flange connection.

[0017] Further, the gasification chamber of the gasifier has a double-layer structure, including an inner liner and an outer shell. The inner liner adopts a refractory brick structure or a water-cooled wall structure. The gasification operation temperature is 1200°C to 1500°C, and the gasification pressure is 1.0 Mpa to 6.4 Mpa.

[0018] Further, the micro-cyclone separator is located at the end of the radiant waste heat boiler and is arranged in an annular array along the inner diameter of the furnace body, and the number of arrangements is calculated according to the synthesis gas volume.

[0019] Further, the micro-cyclone annular gas collecting pipe is designed according to the project implementation situation. It can be the structure of a whole circular pipe, or composed of two semi-circular pipes, or composed of multiple arc-shaped pipes. Corresponding synthesis gas outlets are provided on each section of the pipe.

[0020] The process flow of the biomass gasification and heat recovery unit is as follows: The superheated steam and oxygen premixed by the steam-oxygen mixer and the biomass powder from the biomass conveying unit are sprayed into the gasification chamber of the gasifier through the burner together to generate high-temperature gasification reaction to produce synthesis gas. The high-temperature synthesis gas at a temperature of 1200°C to 1500°C flows from the outlet of the gasification chamber of the gasifier to the slag gas treatment chamber of the gasifier from top to bottom. The synthesis gas first recovers heat through the built-in radiant waste heat boiler in the slag gas treatment chamber of the gasifier to reduce the temperature of the synthesis gas to 700°C to 850°C, and then is mixed with the low-temperature synthesis gas from the recycle machine and quenched to 500°C to 650°C to avoid the alkali metal contamination temperature section of the biomass ash. Subsequently, the synthesis gas continues to flow downward. In the slag gas treatment chamber of the gasifier, the coarse slag directly falls into the lower furnace slag water bath section due to gravity. Most of the fine ash is separated from the synthesis gas under the action of the micro-cyclone separator and falls into the water bath. The separated synthesis gas is collected by the micro-cyclone annular gas collecting pipe and discharged from the synthesis gas outlet of the gasifier, and then enters the convection waste heat boiler through the gas transmission pipe to further recover heat and cool down to 320°C to 250°C and then sent to the synthesis gas purification unit; The coarse slag separated in the slag gas treatment chamber of the gasifier and a small amount of fine ash that does not enter the micro-cyclone separator are broken by the slag breaker below and fall into the slag discharge lock hopper, and are discharged into the slag water treatment unit through the slag discharge lock hopper, while a large amount of fine ash enters the slag water treatment unit with the black water discharged from the slag gas treatment chamber of the gasifier for treatment.

[0021] The slag water treatment unit conducts coarse slag separation, black water and grey water flashing, fine ash separation, grey water deoxidation, and grey water preheating treatment on the furnace slag. After treatment, the separated slag is transported out for disposal, and the regenerated grey water is preheated and pressurized and then sent back to the synthesis gas purification unit for use as washing makeup water.

[0022] The syngas purification unit includes a gas-liquid mixer, a scrubbing tower, a quench water pump and corresponding pipelines. The process flow is as follows: The scrubbing tower obtains the source of scrubbing liquid from the process condensate and the slag water treatment unit; The syngas carrying a small amount of dust from the convective waste heat boiler first enters the gas-liquid mixer and mixes with the ash water pumped from the scrubbing tower by the quench water pump. After the syngas is humidified and the fine ash particles are agglomerated in the gas-liquid mixer, it enters the scrubbing tower. The syngas is washed by water bath in the scrubbing tower and then flows upward in the scrubbing tower to contact the process condensate countercurrently to achieve dust removal and purification of the syngas, reducing the dust content in the syngas to less than 1mg / Nm³, and at the same time reducing the temperature of the syngas to the temperature required by the subsequent process and then sending it to the next section (the specific temperature is designed according to the requirements of the subsequent process flow); At the same time, the ash water pumped from the scrubbing tower by the quench water pump also enters the slag gas treatment chamber of the gasifier through another pipeline for ash slag cooling.

[0023] The steam-water system unit includes a steam drum and a boiler feed water circulation pipeline, which serves as an auxiliary system for the biomass gasification and heat recovery unit. The process flow of the steam-water system unit is as follows: The boiler feed water in the steam drum is sent to the radiant waste heat boiler and the convective waste heat boiler to generate corresponding steam for subsequent procedures; The pressure of the corresponding steam and the number of steam drums are combined or split according to the actual situation, and the user can flexibly select technical parameters for engineering design; The boiler feed water can also be designed as a natural circulation according to the actual situation, and the boiler circulation pump is only used as a backup option in special cases.

[0024] The beneficial technical effects of this technical solution are as follows:

[0025] First, the present invention adopts the biomass dry powder pressurized entrained flow gasification technology route, which overcomes the disadvantages of small single furnace processing capacity, large equipment footprint and low economy of traditional atmospheric pressure biomass gasification, and overcomes the disadvantages of oil tar and methane in the syngas of fixed bed pressurized gasification and fluidized bed pressurized gasification technologies. It has the characteristics of high effective gas component, high cold gas efficiency, syngas without tar and methane, and low operation cost, and can create higher economic benefits;

[0026] Second, the present invention adopts the full waste heat boiler process of radiant waste heat boiler and convective waste heat boiler, and through the setting of circulating gas curtain purging and gas quench of low-temperature syngas, it can effectively avoid slagging, ash accumulation on the heating surface of the radiant waste heat boiler, and avoid the problem of alkali metal contamination in the syngas, so as to ensure the efficient heat recovery and long-term stable operation of the process system of the present invention;

[0027] III. A number of micro - cyclone separators arranged in an array are provided at the lower end of the radiation waste heat boiler in the gasification furnace slag gas treatment chamber of the present invention. Through the micro - cyclone separators, a large amount of fine ash in the syngas can be separated in the gasification furnace slag gas separation chamber. Compared with the complex dry ash removal system arranged after the convection waste heat boiler in the traditional process, the present invention has the characteristics of simple ash removal equipment, small floor area, and low operating cost, which can reduce the investment and operating cost of the ash removal system and ensure stable and reliable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the high - efficiency biomass dry powder pressurized entrained - flow gasification process system in the present invention.

[0029] Figure 2 It is a schematic diagram of the biomass dry powder pressurized entrained - flow gasification furnace in the present invention.

[0030] Figure 3 It is a schematic diagram of the layout of the micro - cyclone separators in the gasification furnace slag gas treatment chamber of the present invention.

[0031] Figure 4 It is a top - view schematic diagram of the layout of a kind of micro - cyclone annular gas collector in the present invention.

[0032] Figure 5 It is a top - view schematic diagram of the layout of another kind of micro - cyclone annular gas collector in the present invention.

[0033] In the figure, 11 is the material feed bin, 12 is the material conveying device, 13 is the material tearing machine, 14 is the crushed material conveying device, 15 is the material drying and pulverizing device, 16 is the powder conveying device; 21 is the powder storage bin, 22 is the powder variable - pressure bin, 23 is the material - sending bin; 31 is the burner, 32 is the gasification chamber of the gasification furnace, 33 is the gasification furnace slag gas treatment chamber, 34 is the slag breaker, 35 is the slag discharge lock hopper, 36 is the gas transmission pipe, 37 is the convection waste heat boiler, 38 is the circulating machine, 39 is the steam - oxygen mixer; 321 is the outlet of the gasification chamber of the gasification furnace, 322 is the burner installation port, 323 is the inner liner of the gasification chamber of the gasification furnace, 324 is the outer shell of the gasification chamber of the gasification furnace, 331 is the micro - cyclone separator, 332 is the micro - cyclone annular gas collector, 333 is the radiation waste heat boiler, 334 is the inlet of the gas curtain gas, 335 is the inlet of the quench gas, 336 is the syngas outlet, 337 is the slag discharge port, 338 is the outlet of the quench black water, 339 is the inlet of the boiler feed water, 3310 is the outlet of the boiler feed water, 3311 is the gas curtain soot - blowing port, 3312 is the quench gas injection port; 41 is the gas - liquid mixer, 42 is the scrubbing tower, 43 is the quench water pump; 5 is the slag water treatment unit; 61 is the high - pressure steam drum, 62 is the high - pressure boiler circulating pump, 63 is the medium - pressure steam drum, 64 is the medium - pressure boiler circulating pump. DETAILED DESCRIPTION OF THE INVENTION

[0034] As Figure 1As shown in the figure, an efficient biomass dry powder pressurized entrained flow gasification process system includes six process units: a biomass powder preparation unit, a biomass transportation unit, a biomass gasification and heat recovery unit, a syngas purification unit, a slag water treatment unit, and a steam and water system unit.

[0035] In the gasification process system of this embodiment, its process flow is as follows:

[0036] (1) The purchased biomass is prepared into dry biomass powder by the biomass powder preparation unit;

[0037] (2) The biomass powder is sent to the biomass gasification and heat recovery unit by the biomass transportation unit through pneumatic transportation;

[0038] (3) The biomass powder reacts with steam and oxygen in the biomass gasification and heat recovery unit to generate syngas, achieving efficient heat recovery and completing the separation of coarse slag and most of the fine ash;

[0039] (4) The syngas after heat recovery enters the syngas purification unit to further remove the fine ash in the syngas and then is sent to the next process section for use;

[0040] (5) The slag water and black water in the process system enter the slag water treatment unit. After heat recovery, coarse slag separation, fine ash separation, ash water deoxidation, ash water preheating and other process steps are carried out in the slag water treatment unit, they enter the process system for reuse;

[0041] (6) The steam and water system unit is an auxiliary system of the biomass gasification and heat recovery unit. In this system, the boiler feed water is exchanged heat with the syngas and the heat is recovered. After the heat is recovered, high-pressure steam is generated in the steam and water system and sent out for use.

[0042] The biomass powder preparation unit is composed of a material feed bin 11, a material transfer device 12, a material tearing machine 13, a shredded material transfer device 14, a material drying and powder making device 15, a powder transfer device 16 and related pipelines. Its process flow is as follows: The baled biomass first enters the material feed bin 11, and then is sent into the material tearing machine 13 by the material transfer device 12 to tear the biomass material into shredded materials. The shredded materials are sent into the material drying and powder making device 15 by the shredded material transfer device 14. In the material drying and powder making device 15, the shredded materials are simultaneously made into biomass powder and dried. The particle size range of the biomass powder is approximately 10μm to 200μm, and the moisture content of the biomass powder is roughly controlled at 2% - 6%. The generated biomass dry powder is sent into the biomass transportation unit by the powder transfer device 16.

[0043] The material drying and powder making device 15 uses mechanical pulverization to prepare the biomass shredded materials into powder. This equipment also has a drying function, and the drying method is selected as the electric auxiliary heating method using green electricity.

[0044] The biomass conveying unit consists of a powder storage bin 21, a powder pressure-changing bin 22, a feeding bin 23 and related pipelines. Its technological process is as follows: The dry biomass powder from the biomass powder-making unit first enters the powder storage bin 21 for standby. The biomass powder in the powder storage bin 21 enters the feeding bin 23 after being pressurized by the powder pressure-changing bin 22. After the materials in the powder pressure-changing bin 22 are discharged into the feeding bin 23, the pressure is relieved and the powder is added again for the next feeding into the feeding bin 23. The feeding bin 23 continuously sends the biomass powder into the biomass gasification and heat recovery unit through pneumatic conveying by carrier gas to carry out gasification reaction.

[0045] The conveying carrier gas and the pressurizing gas of the biomass conveying unit are inert gases CO2 or N2. Preferably, in the process of producing green methanol by biomass gasification, it is better to use CO2 as the conveying carrier gas and the pressurizing gas.

[0046] The biomass gasification and heat recovery unit consists of a burner 31, a gasification chamber 32 of the gasifier, a slag gas treatment chamber 33 of the gasifier, a slag breaker 34, a slag discharge lock hopper 35, a gas transmission pipe 36, a convection waste heat boiler 37, a circulating machine 38, an oxygen-steam mixer 1139 and corresponding pipelines. The burner 31 is fixed at the upper end of the gasification chamber 32 of the gasifier through the burner installation port 322. The gasification chamber 32 of the gasifier is communicated with the slag gas treatment chamber 33 of the gasifier through the gasification chamber outlet 321 of the gasifier. The slag breaker 34 is arranged at the bottom of the slag gas treatment chamber 33 of the gasifier. The slag discharge pipeline of the slag breaker 34 is connected to the slag discharge lock hopper 35, and the slag discharge pipeline of the slag discharge lock hopper 35 is connected to the slag water treatment unit 5.

[0047] The gasification chamber 32 of the gasifier includes two-layer structures of an inner liner 323 of the gasification chamber of the gasifier and an outer shell 324 of the gasification chamber of the gasifier.

[0048] The process flow is as follows: The superheated steam and oxygen premixed by the steam-oxygen mixer 39 and the biomass powder from the biomass delivery unit are sprayed into the gasification chamber 32 of the gasifier through the burner 31 installed at the top of the gasifier to undergo a high-temperature gasification reaction. The reaction in the gasification chamber is set at 2.8 Mpa, and the gasification temperature is set at about 1300 °C. The high-temperature syngas generated flows from the outlet 321 of the gasification chamber of the gasifier downward into the slag gas treatment chamber 33 of the gasifier. The syngas first recovers heat through the built-in radiant waste heat boiler 333 in the slag gas treatment chamber 33 of the gasifier to reduce the temperature of the syngas to about 800 °C, and then is mixed with the low-temperature syngas recycled from the back of the scrubber 42 by the recycle machine 38 to be quenched and cooled to about 600 °C to avoid the alkali metal contamination temperature range of the biomass ash. Subsequently, the syngas continues to flow downward. In the slag gas treatment chamber 33 of the gasifier, the coarse slag directly drops into the lower water bath due to gravity, and most of the fine ash is also separated from the syngas under the action of the micro-cyclone separator 331 and drops into the water bath. The separated syngas is collected by the micro-cyclone annular gas collecting pipe 332 and discharged from the syngas outlet 336 out of the gasifier, and then enters the convection waste heat boiler 37 through the gas transmission pipe 36 to further recover heat and be cooled to about 260 °C and then sent to the syngas purification unit; while the coarse slag and a small amount of fine ash separated in the slag gas treatment chamber 33 of the gasifier are crushed by the slag crusher 34 below and drop into the slag discharge lock hopper 35, and are discharged into the slag water treatment unit 5 through the slag discharge lock hopper 35, and a large amount of fine ash enters the slag water treatment unit 5 with the black water discharged from the slag gas treatment chamber 33 for treatment.

[0049] The syngas purification unit consists of a gas-liquid mixer 41, a scrubber 42, a quench water pump 43, and related auxiliary facilities. The process flow is as follows: The syngas carrying a small amount of dust from the convection waste heat boiler 37 first enters the gas-liquid mixer 41 and is mixed with the ash water extracted from the scrubber 42 by the quench water pump 43. The syngas is humidified in the gas-liquid mixer 41 and the fine ash particles are agglomerated and then enter the scrubber 42. The syngas is first washed by water bath in the scrubber 42, and then the syngas flows upward and contacts the process condensate countercurrently on the internal components of the scrubber 42 to achieve dust removal and purification of the syngas, reducing the dust content in the syngas to less than 1 mg / Nm³; in addition, a part of the ash water extracted from the scrubber 42 by the quench water pump 43 also enters the slag gas treatment chamber 33 of the gasifier for ash slag cooling.

[0050] The slag water treatment unit conducts treatments such as coarse slag separation, flashing of black water and ash water, fine ash separation, deoxidation of ash water, and preheating of ash water for the ash slag in the unit, realizes ash slag separation and regeneration and recycling of ash water. The separated ash slag is transported out for disposal, and the regenerated ash water is preheated and pressurized and then sent back to the scrubber 42 as makeup water for the scrubber 42.

[0051] The pressure of the steam-water system unit and the number of steam drums are designed according to the actual situation. In this embodiment, it is composed of a high-pressure steam drum 61, a high-pressure boiler circulating pump 62, a medium-pressure steam drum 63, a medium-pressure boiler circulating pump 64 and related auxiliary facilities. Its main process flow is as follows: The high-pressure boiler circulating pump 62 sends the boiler feed water in the high-pressure steam drum 61 into the radiant waste heat boiler 333 to generate high-pressure steam. After the high-pressure steam returns to the high-pressure steam drum 61, it is sent to other users for use; The medium-pressure boiler circulating pump 64 sends the boiler feed water in the medium-pressure steam drum 63 into the convective waste heat boiler 37 to generate medium-pressure steam. After the medium-pressure steam returns to the medium-pressure steam drum 63, it enters the convective waste heat boiler 37 again to generate superheated steam. A small amount of superheated steam enters the steam-oxygen mixer 1139 and then enters the gasifier together with oxygen to react, and most of the superheated steam is sent to other users for use.

[0052] For the above gasification process system, as Figure 2 shown, the specific design of the biomass gasification and heat recovery unit is as follows:

[0053] The burner 31, the gasification chamber 32 of the gasifier, the slag gas treatment chamber 33 of the gasifier, the slag breaker and the slag discharge lock hopper are longitudinally arranged and connected in sequence. The burner 31 is installed at the top of the gasification chamber 32 of the gasifier. The upper section of the gasifier is the gasification chamber 32 of the gasifier, and the lower section is the slag gas treatment chamber 33 of the gasifier.

[0054] The burner 31 is provided with 2 process medium channels, and the gasification chamber 32 of the gasifier and the slag gas treatment chamber 33 of the gasifier are selected to be integrally processed and manufactured.

[0055] The gasification chamber 32 of the gasifier has a double-layer structure, including an inner liner 323 and an outer shell 324. In this embodiment, the inner liner 323 of the gasification chamber of the gasifier adopts a refractory brick structure. The gasification operation temperature is set at 1300 °C according to the material characteristics, and the gasification pressure is set at 2.8 Mpa according to the whole plant process considerations.

[0056] The slag gas treatment chamber 33 of the gasifier is connected to the convective waste heat boiler through a gas transmission pipe. The synthesis gas of the circulating machine is connected to the slag gas treatment chamber 33 of the gasifier in two paths. One steam output pipeline of the convective waste heat boiler is connected to the steam-oxygen mixer 11, and the mixed gas output pipeline of the steam-oxygen mixer 11 is connected to the burner 31.

[0057] The slag gas treatment chamber 33 of the gasifier includes a radiant waste heat boiler 333 in the upper and middle sections and a slag water bath section in the lower section; The radiant waste heat boiler is provided with a low-temperature synthesis gas inlet purging route, a low-temperature synthesis gas inlet cooling route and a synthesis gas discharge route.

[0058] At the lower end of the radiant waste heat boiler 333, there is one boiler feed water inlet 339. At the upper end of the radiant waste heat boiler 333, there is one boiler feed water outlet 3310. At the upper end of the radiant waste heat boiler 333, there are two air curtain gas inlets 334. The heating surface of the radiant waste heat boiler 333 is provided with a set of annular air curtain soot blowing nozzles 3311 connected to the air curtain air inlets every 1 meter in the vertical space. The jet gas velocity range of the air curtain soot blowing nozzles 3311 is 15 - 45 m / s. The topmost set of air curtain soot blowing nozzles 3311 uses the low-temperature syngas from the recycle machine 38 for continuous air curtain purging, and the other air curtain nozzles are purged intermittently, so as to ensure that the high-temperature heating surface at the top does not slag, and the heating surface below does not accumulate ash. The air curtain gas inlets 334 and multiple sets of air curtain soot blowing nozzles 3311 form a low-temperature syngas inlet purging route.

[0059] At the lower end of the radiant waste heat boiler 333, there is a quench gas inlet 335. The low-temperature syngas from the recycle machine 38 enters through the quench gas inlet 335 into the annular quench gas nozzles 3312 arranged at the lower end of the radiant waste heat boiler 333 and continuously jets gas into the furnace for cooling. The jet gas velocity range of the quench gas nozzles is 5 - 30 m / s, so that the syngas quenching and cooling avoid the temperature range of alkali metal contamination. The micro-cyclone annular gas collector 332 can be Figure 4 the structure composed of the entire circular pipe shown in Figure 5 , or can be Figure 5 the structure composed of two arc-shaped circular pipes shown in . In this embodiment, the structure shown in is adopted. At the lower end of the radiant waste heat boiler 333, there is a micro-cyclone annular gas collector 332 composed of two semi-circular pipes for collecting the syngas after ash removal by the micro-cyclone separator 331. The micro-cyclone annular gas collector 332 is connected to two syngas outlets 336. At the lower end of the micro-cyclone annular gas collector 332, a number of micro-cyclone separators 331 are evenly distributed in an annular array to realize the separation of syngas and fine ash; here, the quench gas inlet 335 and the annular quench gas nozzles 3312 form a low-temperature syngas inlet cooling route.

[0060] The micro-cyclone separator 331, the micro-cyclone annular gas collector 332, and the syngas outlet 336 form a syngas discharge route. The syngas separated from fine ash enters the subsequent convective waste heat boiler through two gas pipelines 36 from the syngas outlet 336. At the lower end of the gasification furnace slag gas treatment chamber 33, there is a slag discharge port 337. Immediately below the slag discharge port 337, a slag breaker 34 is installed. The coarse slag generated by gasification enters the slag breaker 34 after passing through the lower section water bath of the gasification furnace slag gas treatment chamber 33. At the lower section of the gasification furnace slag gas treatment chamber 33, there is also a quench black water outlet 338. The black water carrying a large amount of fine ash is discharged into the slag water treatment unit 5 through the quench black water outlet 338.

[0061] As Figure 3As shown, the micro cyclone separator 331 is located at the end of the radiant waste heat boiler 333 and is arranged in an annular array. The number of the micro cyclones is several, which is calculated according to the synthesis gas volume. The inlet pipe of the micro cyclone is preferably arranged parallel to the tangent of the annular circumference.

[0062] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An efficient biomass dry powder pressurized entrained flow gasification process system, characterized in that: It includes a biomass pulverizing unit, a biomass conveying unit, a biomass gasification and heat recovery unit, a syngas purification unit, a slag and water treatment unit (5), and a steam-water system unit; The gasification process flow of the gasification process system is as follows: The biomass raw material is prepared into biomass dry powder by the biomass pulverizing unit, and the biomass dry powder is sent to the biomass gasification and heat recovery unit by the biomass conveying unit through pneumatic conveying; The biomass powder reacts with steam and oxygen in the biomass gasification and heat recovery unit to generate syngas, and heat recovery is carried out to complete the separation of coarse slag and fine ash; The syngas after heat recovery enters the syngas purification unit to further remove the fine ash not separated in the syngas and then is sent to the next process section for use; The slag water and black water in the process system enter the slag and water treatment unit (5). After steps of heat recovery, coarse slag separation, fine ash separation, ash water deoxidation, and ash water preheating in the slag and water treatment unit (5), they enter the process system for reuse; In the steam-water system unit, the boiler feed water is exchanged heat with the syngas and heat is recovered. After heat recovery, high-pressure steam is generated in the steam-water system and sent out for use; The biomass gasification and heat recovery unit includes a burner (31), a gasification furnace gasification chamber (32), a gasification furnace slag and gas treatment chamber (33), a slag breaker (34), a slag discharge lock hopper (35), a convection waste heat boiler (37), a recycle machine (38), a steam-oxygen mixer (39) and corresponding pipelines; the burner (31), the gasification furnace gasification chamber (32), the gasification furnace slag and gas treatment chamber (33), the slag breaker (34), and the slag discharge lock hopper (35) are longitudinally arranged and connected in sequence. The gasification furnace slag and gas treatment chamber (33) is connected to the convection waste heat boiler (37) through a gas transmission pipe (36). The syngas of the recycle machine (38) is connected to the gasification furnace slag and gas treatment chamber (33) in two paths. One steam output pipeline of the convection waste heat boiler (37) is connected to the steam-oxygen mixer (39), and the mixed gas output pipeline of the steam-oxygen mixer (39) is connected to the burner (31); the gasification furnace slag and gas treatment chamber (33) includes a radiation waste heat boiler (333) in the upper and middle sections and a furnace slag water bath section in the lower section; the radiation waste heat boiler (333) is provided with a low-temperature syngas inlet purging route, a low-temperature syngas inlet cooling route, and a syngas discharge route; Among them, one or more boiler feed water outlets (3310) are arranged at the top of the shell of the radiant waste heat boiler (333), one or more boiler feed water inlets (339) are arranged at the lower end of the side wall of the shell, one or more air curtain gas inlets (334) are installed at the upper end of the side wall of the shell, and multiple groups of annular air curtain soot blowing nozzles (3311) connected to the air curtain gas inlets (334) are arranged in the vertical space of the heating surface of the radiant waste heat boiler (333). The jet gas velocity matching pressure of the air curtain soot blowing nozzles (3311) is set between 15 and 45 m / s. The air curtain soot blowing nozzles (3311) use the low-temperature synthesis gas from the recycle machine (38) to conduct continuous or intermittent air curtain soot blowing to ensure that the heating surface does not slag or accumulate ash. The air curtain gas inlets (334) and multiple groups of air curtain soot blowing nozzles (3311) form a low-temperature synthesis gas intake and soot blowing route; a quench gas inlet (335) and a boiler feed water inlet (339) are installed at the lower part of the side wall of the shell of the radiant waste heat boiler (333), and a synthesis gas outlet (336) is installed below the side wall lower than the quench gas inlet (335) and the boiler feed water inlet (339); an annular quench gas nozzle (3312) is arranged inside the radiant waste heat boiler (333) at the height corresponding to the quench gas inlet (335), and a micro-cyclone annular gas collector (332) is arranged at the height corresponding to the synthesis gas outlet (336). A number of micro-cyclone separators (331) are evenly distributed at the lower end of the micro-cyclone annular gas collector (332); the quench gas inlet (335) and the annular quench gas nozzle (3312) form a low-temperature synthesis gas intake and cooling route, and the gas velocity of the quench gas nozzle (3312) is set between 5 and 30 m / s; the micro-cyclone separators (331), the micro-cyclone annular gas collector (332), and the synthesis gas outlet (336) form a synthesis gas discharge route; The micro-cyclone separators (331) are located at the end of the radiant waste heat boiler (333), and are arranged in an annular array along the inner diameter of the furnace body, and the number of arrangements is calculated according to the synthesis gas volume.

2. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 1, wherein: The biomass powder preparation unit includes a material feed bin (11), a material conveying device (12), a material tearing machine (13), a shredded material conveying device (14), a material drying and powder preparation device (15), a powder conveying device (16) and corresponding pipelines; the feed inlet of the material feed bin (11) is connected to the biomass raw material source, the discharge outlet of the material feed bin (11) is connected to the feed end of the material conveying device (12), the discharge end of the material conveying device (12) is connected to the feed inlet of the material tearing machine (13), the discharge outlet of the material tearing machine (13) is connected to the feed end of the shredded material conveying device (14), the discharge end of the shredded material conveying device (14) is connected to the feed inlet of the material drying and powder preparation device (15), the discharge outlet of the material drying and powder preparation device (15) is connected to the feed end of the powder conveying device (16), and the discharge end of the powder conveying device (16) is connected to the biomass conveying unit; The process flow of the biomass powder making unit is as follows: The biomass raw materials first enter the material feeding bin (11), and then are sent into the material tearing machine (13) through the material conveying device (12) to tear the biomass materials into shredded materials. The shredded materials are sent into the material drying and powder making device (15) through the shredded material conveying device (14). In the material drying and powder making device (15), the shredded materials are simultaneously pulverized and dried to produce biomass powder. The particle size range of the biomass powder is 10μm - 200μm, and the moisture content of the biomass powder is controlled at 2% - 6%. The generated biomass dry powder is sent into the biomass conveying unit through the powder conveying device (16).

3. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 2, wherein: The material drying and powder making device (15) adopts a mechanical pulverization method to prepare the biomass shredded materials into powder and simultaneously dry the biomass powder. The drying method selects electric auxiliary heating, or steam auxiliary heating, or low oxygen content hot air drying.

4. An efficient biomass dry powder pressurized entrained flow gasification process system according to claim 2, characterized in that: The biomass conveying unit includes a powder storage bin (21), a powder variable pressure bin (22), a feeding bin (23) and corresponding pipelines. The feeding port of the powder storage bin (21) is connected to the material pipeline connected to the discharging end of the powder conveying device (16). The discharging port of the powder storage bin (21) is connected to the feeding port of the powder variable pressure bin (22). The discharging port of the powder variable pressure bin (22) is connected to the feeding port of the feeding bin (23). The discharging port of the feeding bin (23) is connected to the biomass gasification and heat recovery unit. The process flow of the biomass conveying unit is as follows: The biomass dry powder from the biomass powder making unit first enters the powder storage bin (21) for standby. The biomass powder in the powder storage bin (21) enters the feeding bin (23) after being pressurized by the powder variable pressure bin (22). After the materials in the powder variable pressure bin (22) are discharged into the feeding bin (23), they are depressurized and then the powder is added again for the next feeding into the feeding bin (23). The feeding bin (23) continuously sends the biomass powder into the biomass gasification and heat recovery unit through the carrier gas by pneumatic conveying for gasification reaction.

5. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 4, wherein: The conveying carrier gas and pressurizing gas of the biomass conveying unit are inert gases CO2 or N2.

6. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 4, characterized in that: The arrangement angle of the micro-cyclone inlet pipe of the micro-cyclone separator (331) should be parallel to the tangent of the annular circumference.

7. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 4, characterized in that: Designed according to the project implementation situation, the micro-cyclone annular gas collecting pipe (332) is a whole circular pipe structure, or is composed of two semi-circular pipes, or is composed of multiple arc-shaped ring pipes. Each section of the ring pipe is provided with a corresponding syngas outlet (336).

8. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 4, wherein: The burner (31) has a water-cooled protection structure and is provided with at least 2 process medium channels.

9. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 4, characterized in that: The gasification chamber (32) of the gasifier has a double-layer structure, including the inner liner (323) of the gasification chamber of the gasifier and the outer shell (324) of the gasification chamber of the gasifier. The inner liner adopts a refractory brick structure or a water-cooled wall structure. The gasification operation temperature is 1200℃ - 1500℃, and the gasification pressure is 1.0Mpa - 6.4Mpa.

10. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 4, characterized in that The process flow of the biomass gasification and heat recovery unit is as follows: Superheated steam and oxygen premixed by the steam-oxygen mixer (39) and biomass powder from the biomass feeding unit are sprayed into the gasification chamber (32) of the gasifier through the burner (31) to undergo a high-temperature gasification reaction to generate syngas. The high-temperature syngas at a temperature of 1200°C to 1500°C flows from top to bottom into the slag gas treatment chamber (33) of the gasifier from the outlet (321) of the gasification chamber of the gasifier. The syngas first recovers heat through the built-in radiant waste heat boiler (333) in the slag gas treatment chamber (33) of the gasifier to reduce the temperature of the syngas to 700°C to 850°C, and then is mixed with the low-temperature syngas from the recycle compressor (38) and quenched to 500°C to 650°C to avoid the alkali metal contamination temperature range of the biomass ash slag. Subsequently, the syngas continues to flow downward. In the slag gas treatment chamber (33) of the gasifier, the coarse slag directly falls into the lower slag water bath section due to gravity. Most of the fine ash is separated from the syngas under the action of the micro-cyclone separator (331) and falls into the water bath. The separated syngas is collected by the micro-cyclone annular gas collecting pipe (332) and discharged from the syngas outlet (336) of the gasifier, and then enters the convection waste heat boiler (37) through the gas transmission pipe (36) to further recover heat and cool down to 320°C to 250°C and then sent to the syngas purification unit; The coarse slag separated in the slag gas treatment chamber (33) of the gasifier and a small amount of fine ash that does not enter the micro-cyclone separator (331) are broken by the lower slag breaker (34) and then fall into the slag discharge lock hopper (35), and are discharged into the slag water treatment unit (5) through the slag discharge lock hopper (35) for treatment, while a large amount of fine ash enters the slag water treatment unit (5) with the black water discharged from the slag gas treatment chamber (33) for treatment.

11. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 1, characterized in that: The slag water treatment unit (5) conducts coarse slag separation, flash evaporation of black water and ash water, fine ash separation, deoxygenation of ash water, and preheating treatment of ash water on the slag. After treatment, the separated ash slag is transported out for disposal, and the regenerated ash water is preheated and pressurized and then sent back to the syngas purification unit for use as washing makeup water.

12. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 1 or 11, characterized in that: The syngas purification unit includes a gas-liquid mixer (41), a washing tower (42), a quench water pump (43), and corresponding pipelines; The process flow of the syngas purification unit is as follows: The washing tower (42) obtains the washing liquid source from the process condensate and the slag water treatment unit (5); The syngas carrying a small amount of dust from the convection waste heat boiler (37) first enters the gas-liquid mixer (41) and is mixed with the ash water extracted from the washing tower (42) by the quench water pump (43). The syngas is humidified in the gas-liquid mixer (41) and the fine ash particles are agglomerated and then enter the washing tower (42). The syngas is washed by water bath in the washing tower (42) and then contacts the process condensate countercurrently upward in the washing tower (42) to achieve dust removal and purification of the syngas, reducing the dust content in the syngas to less than 1 mg / Nm³; At the same time, the ash water extracted from the washing tower (42) by the quench water pump (43) also enters the slag gas treatment chamber (33) of the gasifier through another pipeline for ash slag cooling.

13. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 4, wherein: The steam-water system unit includes a high-pressure steam drum (61), a high-pressure boiler circulation pump (62), a medium-pressure steam drum (63), a medium-pressure boiler circulation pump (64) and corresponding pipelines; as an auxiliary system of the biomass gasification and heat recovery unit, the technological process of the steam-water system unit is as follows: the high-pressure boiler circulation pump (62) sends the boiler feed water in the high-pressure steam drum (61) into the radiant waste heat boiler (333) to generate high-pressure steam, and the high-pressure steam returns to the high-pressure steam drum (61) and then is sent to other users for use; the medium-pressure boiler circulation pump (64) sends the boiler feed water in the medium-pressure steam drum (63) into the convective waste heat boiler (37) to generate medium-pressure steam, and the medium-pressure steam returns to the medium-pressure steam drum (63) and then enters the convective waste heat boiler (37) again to generate superheated steam. A small amount of superheated steam enters the steam-oxygen mixer (39) and then reacts with oxygen in the gasifier, and most of the superheated steam is sent to other users for use.

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