Efficient biomass dry powder pressurized entrained-flow bed gasification process system

Abstract

The invention discloses an efficient biomass dry powder pressurized entrained-flow bed gasification process system. A biomass raw material is prepared into dry powder through a biomass powder preparation unit, the dry powder is conveyed to a biomass gasification and heat recovery unit through a biomass conveying unit, biomass powder, steam and oxygen are subjected to gasification reaction in the biomass gasification and heat recovery unit to generate synthesis gas, heat recovery is performed, and coarse slag and fine ash are separated; the synthesis gas subjected to heat recovery enters a synthesis gas purification unit to further remove fine ash and then is sent to a next working section for use; slag water and black water enter the slag water treatment unit to be treated and then recycled; the steam-water system unit exchanges heat between boiler feed water and synthesis gas and recovers heat, and high-pressure steam is generated in a steam-water system after heat recovery and is sent out for use. The biomass dry powder pressurized entrained-flow bed gasification technical route has the characteristics of high effective gas composition, high cold coal gas efficiency, no tar or methane in synthesis gas and low operation cost, and can realize better economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of biomass resource gasification and utilization, and in particular to a high-efficiency biomass dry powder pressurized fluidized bed gasification process system. Background Art

[0002] Under the background of "dual carbon", the use of biomass as zero-carbon fuel to prepare green chemicals has attracted widespread attention, especially the market demand for "green methanol". The market predicts that by 2030, the global demand for green methanol will exceed 30 million tons / year, and the market size of green methanol is expected to reach 250 million tons in 2050. In December 2023, green methanol was also included in my country's modern energy system planning to strengthen the demonstration and application of green methanol in the fields of industry, transportation, power generation, construction, consumption, etc. Biogasification of green methanol based on biomass gasification and biomass gasification coupled with green hydrogen to produce green methanol are currently the most suitable technical routes for large-scale production and cost advantages, and are the absolute mainstream technical routes for the current development of green methanol. As a key common technology for green methanol, biomass gasification technology currently has no mature and efficient biomass gasification technology that has been applied on a large scale. The advantages and disadvantages of biogasification technology are the main technical bottlenecks restricting the development of the green methanol industry.

[0003] At present, in order to meet the needs of chemical production, the research and application of biomass gasification technology is developing from atmospheric gasification technology to pressurized gasification technology. The biomass pressurized gasification technology routes being studied or promoted mainly include three technical routes: biomass fixed bed gasification technology, biomass fluidized bed gasification technology, and biomass fluidized bed gasification technology. The production of synthesis gas by biomass fixed bed gasification technology has the disadvantage that tar and methane are difficult to handle. The synthesis gas produced by biomass fluidized bed gasification technology has a lower tar content, but its synthesis gas still contains a large amount of methane that is difficult to handle. Biomass fixed bed gasification technology and biomass fluidized bed gasification technology usually require a high-temperature reforming furnace to be set up after the gasifier to treat the tar and methane in the synthesis gas, which leads to a significant increase in its investment cost, and there are also certain doubts about the operating stability and reliability of the high-temperature reforming furnace. The synthesis gas produced by biomass fluidized flow gasification technology itself has the characteristics of almost no tar and methane, but the problem of heat recovery of its high-temperature synthesis gas has not been well solved, especially the high alkali metal content in biomass, which easily causes the heating surface of the waste heat boiler to be contaminated, resulting in low efficiency of the heat recovery equipment. Therefore, the patent of this invention proposes a high-efficiency biomass dry powder pressurized fluidized flow gasifier and process system, which can achieve efficient biomass gasification and full heat recovery, and will effectively promote the development of the green methanol industry with biomass gasification as the technical source. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention proposes a high-efficiency biomass dry powder pressurized fluidized bed gasification process system, which mainly solves a series of process problems in the biomass gasification process and is applied to biomass gasification to produce synthesis gas. It can realize process steps such as biomass powder making, biomass pneumatic conveying, biomass gasification, high-efficiency heat recovery of synthesis gas, synthesis gas purification, and system slag water treatment, thereby efficiently preparing biomass into synthesis gas, realizing high-efficiency biomass powder making and high-efficiency heat recovery of synthesis gas (anti-contamination).

[0005] In order to achieve the above technical objectives, the following technical solutions are proposed: A high-efficiency biomass dry powder pressurized fluidized bed gasification process system, characterized by comprising a biomass powder making unit, a biomass conveying unit, a biomass gasification and heat recovery unit, a synthesis gas purification unit, a slag water treatment unit, and a steam-water system unit.

[0006] 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 powder making unit, and the biomass dry powder is pneumatically conveyed to the biomass gasification and heat recovery unit by the biomass conveying unit; the biomass powder, steam and oxygen undergo a gasification reaction in the biomass gasification and heat recovery unit to generate synthesis gas, and heat recovery is performed to complete the separation of coarse slag and fine ash; the synthesis gas after heat recovery enters the synthesis gas purification unit to further remove the unseparated fine ash in the synthesis gas and then is sent to the next stage for use; the slag water and black water in the process system enter the slag water treatment unit, and after the steps of heat recovery, coarse slag separation, fine ash separation, ash water deoxygenation and ash water preheating are performed in the slag water treatment unit, they enter the process system for repeated use; in the steam-water system unit, the boiler feed water is heat exchanged with the synthesis gas and the heat is recovered, and after the heat is recovered, high-pressure steam is generated in the steam-water system and sent out for use.

[0007] The biomass powder making unit includes a material feed bin, a material conveying device, a material tearing machine, a crushing conveying device, a material drying and powder making device, a powder conveying device and corresponding pipelines; the feed port of the material feed bin is connected to the source of biomass raw materials, the discharge port of the material feed bin is connected to the feed end of the material conveying device, the discharge end of the material conveying device is connected to the feed port of the material tearing machine, the discharge port of the material tearing machine is connected to the feed end of the crushing conveying device, the discharge end of the crushing conveying device is connected to the feed port of the material drying and powder making device, the discharge port of the material drying and powder making device is connected to the feed end of the powder conveying device, and the discharge end of the powder conveying device is connected to the biomass conveying unit. The process flow of the biomass powder making unit is as follows: the biomass raw material first enters the material feed bin, and then is sent to the material tearing machine through the material conveying device to tear the biomass material into fragments, and the fragments are sent to the material drying and powder making device through the fragment conveying device, and the fragments are simultaneously biomass powdered and dried in the material drying and powder making device, the particle size range of the biomass powder is: 10μm~200μm, the water content of the biomass powder is controlled at 2%~6%, and the generated biomass dry powder is sent to the biomass conveying unit through the powder conveying device.

[0008] Furthermore, the material drying and powder making device adopts a mechanical crushing method to prepare biomass crushed materials into powder, and dries the biomass powder at the same time; the drying adopts electric auxiliary heating, steam auxiliary heating, or low oxygen content hot air drying.

[0009] The biomass conveying unit includes a powder storage bin, a powder pressure-changing bin, a dispensing bin and corresponding pipelines; the feed port of the powder storage bin is connected to the material pipeline connected to the discharging end of the powder conveying device, the discharging port of the powder storage bin is connected to the feed port of the powder pressure-changing bin, the discharging port of the powder pressure-changing bin is connected to the feed port of the dispensing bin, and the discharging port of the dispensing bin 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 milling unit first enters the powder storage bin for standby use, the biomass powder in the powder storage bin is pressurized by the powder pressure-changing bin and enters the dispensing bin, the powder is discharged into the dispensing bin and then the powder is added again for the next feeding to the dispensing bin, and the dispensing bin continuously delivers the biomass powder to the biomass gasification and heat recovery unit by means of pneumatic conveying through carrier gas to cause gasification reaction. The powder pressure-changing bin can be set to one or more according to actual conditions.

[0010] Furthermore, the transport carrier gas and pressurizing gas of the biomass transport unit are inert gases CO2 or N2. Preferably, in the process of biomass gasification to produce green methanol, CO2 is preferably used as the transport carrier gas and pressurizing gas.

[0011] The biomass gasification and heat recovery unit includes a burner, a gasification chamber of a gasifier, a gasification slag gas treatment chamber, a slag breaker, a slag lock bucket, a convection waste boiler, a circulation machine, a steam-oxygen mixer and corresponding pipelines. The burner, the gasification chamber of a gasifier, the gasification slag gas treatment chamber, the slag breaker and the slag lock bucket are arranged and connected in sequence longitudinally. The gasification slag gas treatment chamber is connected to the convection waste boiler through a gas pipeline. The synthesis gas of the circulation machine is connected to the gasification slag gas treatment chamber in two ways. One steam output pipeline of the convection waste 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 gasification slag gas treatment chamber includes a radiation waste boiler in the middle and upper section and a slag water bath section in the lower section; the radiation waste boiler is provided with a low-temperature synthesis gas intake purge route, a low-temperature synthesis gas intake cooling route and a synthesis gas discharge route.

[0012] The top of the radiation waste boiler shell is provided with one or more boiler feed water outlets, the lower end of the shell side wall is provided with one or more boiler feed water inlets, the upper end of the shell side wall is provided with one or more air curtain gas inlets, and the heating surface of the radiation waste boiler is arranged with multiple groups of annular air curtain soot blowing ports connected with the air curtain gas inlets in the vertical space, the nozzle air velocity of the air curtain soot blowing ports is set to between 15 and 45 m / s according to the pressure matching, the air curtain soot blowing ports use the low-temperature synthesis gas from the circulation machine to perform continuous or intermittent air curtain blowing to ensure that the heating surface is not slagging and dust accumulation, and the air curtain gas inlet and the multiple groups of air curtain soot blowing ports form a low-temperature synthesis gas intake and blowing route.

[0013] A quenching air inlet and a boiler feed water inlet are installed at the lower part of the shell side wall of the radiation waste boiler, and a synthesis gas outlet is installed below the side wall below the quenching air inlet and the boiler feed water inlet; an annular quenching air nozzle is arranged at the height of the quenching air inlet in the radiation waste boiler, and a micro-cyclone annular air collecting pipe is arranged at the height of the synthesis gas outlet, and a plurality of micro-cyclone separators are evenly distributed at the lower end of the micro-cyclone annular air collecting pipe; the quenching air inlet and the annular quenching air nozzle form a low-temperature synthesis gas intake cooling route, and the quenching air nozzle gas velocity is set between 5 and 30 m / s; the micro-cyclone separator, the micro-cyclone annular air collecting pipe and the synthesis gas outlet form a synthesis gas discharge route.

[0014] Furthermore, the burner has at least two or more process medium channels, and the burner has a water cooling protection function.

[0015] Furthermore, the gasification chamber of the gasifier and the slag gas treatment chamber of the gasifier can be manufactured in an integrated manner, or can be manufactured in a separate manner connected by flanges.

[0016] Furthermore, the gasification chamber of the gasifier is a double-layer structure, including an inner shell and an outer shell. The inner shell adopts a refractory brick structure or a water-cooled wall structure. The gasification operating temperature is 1200°C~1500°C, and the gasification pressure is 1.0Mpa~6.4Mpa.

[0017] Furthermore, the micro-cyclone separator is located at the end of the radiation waste boiler, and is arranged in a circular array along the inner diameter of the furnace body, and the number of arrangements is calculated based on the amount of synthesis gas.

[0018] Furthermore, the micro-cyclone annular gas collecting pipe is designed according to the project implementation situation, and can be a whole circular ring pipe structure, or can be composed of two semi-circular ring pipes, or can be composed of multiple sections of arc-shaped ring pipes, and each section of the ring pipe is provided with a corresponding synthesis gas outlet.

[0019] 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 are sprayed into the gasification chamber of the gasifier through the burner together with the biomass powder from the biomass conveying unit to generate synthesis gas by high-temperature gasification reaction. The high-temperature synthesis gas with a temperature of 1200°C to 1500°C flows from the outlet of the gasification chamber of the gasifier from top to bottom into the gasification furnace slag gas treatment chamber. In the gasification furnace slag gas treatment chamber, the synthesis gas first recovers heat through the built-in radiation waste pot to reduce the synthesis gas temperature to 700°C to 850°C, and then is mixed with the low-temperature synthesis gas from the circulation machine to be quenched and cooled to 500°C to 650°C to avoid the alkali metal contamination temperature section of the biomass ash, and then the synthesis gas continues to flow downward. In the slag gas treatment chamber of the gasification furnace, the coarse slag of the synthesis gas falls directly into the slag water bath section below due to gravity, and most of the fine ash is separated from the synthesis gas by 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 gasifier from the synthesis gas outlet, and then enters the convection waste boiler through the gas transmission pipe to further recover heat and is sent to the synthesis gas purification unit after cooling to 320℃~250℃; the coarse slag separated in the gasification furnace slag gas treatment chamber and a small amount of fine ash that has not entered the micro-cyclone separator are crushed by the slag crusher below and fall into the slag lock bucket, and are discharged into the slag water treatment unit for treatment through the slag lock bucket, while a large amount of fine ash enters the slag water treatment unit for treatment along with the black water discharged from the slag gas treatment chamber of the gasification furnace.

[0020] The slag water treatment unit performs coarse slag separation, black water and gray water flashing, fine ash separation, gray water deoxygenation, and gray water preheating treatment on the slag. After treatment, the separated ash is transported out for disposal, and the regenerated gray water is preheated and pressurized and then sent back to the synthesis gas purification unit for washing and water replenishment.

[0021] The synthesis gas purification unit includes a gas-liquid mixer, a washing tower, a quenching water pump and corresponding pipelines. The process flow is as follows: the washing tower obtains the washing liquid source from the process condensate and the slag water treatment unit; the synthesis gas carrying a small amount of dust from the convection waste boiler first enters the gas-liquid mixer and is mixed with the ash water extracted from the washing tower by the quenching water pump, and the synthesis gas is humidified in the gas-liquid mixer and the fine ash particles are agglomerated before entering the washing tower. After the synthesis gas is washed in the washing tower by a water bath, it contacts the process condensate in the washing tower in countercurrent to achieve the dust removal and purification of the synthesis gas, reducing the dust content in the synthesis gas to less than 1mg / Nm³, and at the same time reducing the synthesis gas temperature to the temperature required for the subsequent process before 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 extracted from the washing tower by the quenching water pump also enters the gasification furnace slag gas treatment chamber through another pipeline for ash cooling.

[0022] 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 radiation waste boiler and the convection waste boiler to generate corresponding steam for use in subsequent procedures; the pressure of the corresponding steam and the number of the steam drums are combined or split according to actual conditions, 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 actual conditions, and the boiler circulation pump is only used as a backup option for special cases.

[0023] The beneficial technical effects of this technical solution are: 1. The present invention adopts the biomass dry powder pressurized fluidized bed gasification technology route, which overcomes the shortcomings of small processing capacity of single furnace, large equipment footprint and low economy of traditional atmospheric biomass gasification, and overcomes the shortcomings of fixed bed pressurized gasification and fluidized bed pressurized gasification technology that the synthetic gas contains oil tar and methane. It has the characteristics of high effective gas component, high cold gas efficiency, no tar and methane in the synthetic gas, and low operating cost, which can create higher economic benefits; Second, the present invention adopts a full waste boiler process of radiation waste boiler and convection waste boiler, and by setting up circulating air curtain purge and gas quenching of low-temperature synthesis gas, it can effectively avoid slagging and dust accumulation on the heating surface of the radiation waste boiler, and avoid alkali metal contamination in the synthesis gas, thereby ensuring that the process system of the present invention achieves efficient heat recovery and long-term stable operation; 3. The present invention sets a plurality of micro-cyclone separators arranged in an array at the lower end of the radiation waste pot in the gasification furnace slag gas treatment chamber. A large amount of fine ash in the synthesis gas can be separated by the micro-cyclone separators in the gasification furnace slag gas separation chamber. Compared with the complex dry ash removal system set after the convection waste pot in the traditional process, the present invention has the characteristics of simple ash removal equipment, small footprint 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

[0024] Figure 1 This is a schematic diagram of the high-efficiency biomass dry powder pressurized fluidized bed gasification process system of the present invention.

[0025] Figure 2 This is a schematic diagram of the biomass dry powder pressurized fluidized flow gasification furnace of the present invention.

[0026] Figure 3 It is a schematic diagram of the arrangement of the micro-cyclone separator in the gasification furnace slag gas treatment chamber of the present invention.

[0027] Figure 4 The figure is a top view schematic diagram of the arrangement of a micro-cyclone annular air collecting pipe in the present invention.

[0028] Figure 5 It is a top view schematic diagram of the arrangement of another micro-cyclone annular air collecting pipe in the present invention.

[0029] In the figure, 11 material feeding bin, 12 material conveying device, 13 material tearing machine, 14 crushing material conveying device, 15 material drying and powdering device, 16 powder conveying device; 21 powder storage bin, 22 powder transformer bin, 23 material delivery bin; 31 burner, 32 gasification chamber of gasifier, 33 gasification slag gas treatment chamber, 34 slag crusher, 35 slag discharge lock bucket, 36 gas transmission pipe, 37 convection waste pot, 38 circulation machine, 39 steam oxygen mixer; 321 gasification chamber outlet of gasifier, 322 burner installation port, 323 gasification chamber liner of gasifier, 324 gasification chamber gasifier, Chemical chamber shell, 331 micro-cyclone separator, 332 micro-cyclone annular gas collecting pipe, 333 radiation waste boiler, 334 air curtain gas inlet, 335 quenching gas inlet, 336 synthesis gas outlet, 337 slag discharge port, 338 quenching black water outlet, 339 boiler feed water inlet, 3310 boiler feed water outlet, 3311 air curtain soot blowing port, 3312 quenching gas nozzle; 41 gas-liquid mixer, 42 washing tower, 43 quenching water pump; 5 slag water treatment unit; 61 high-pressure steam drum, 62 high-pressure boiler circulating pump, 63 medium-pressure steam drum, 64 medium-pressure boiler circulating pump. DETAILED DESCRIPTION

[0030] like Figure 1 As shown, a high-efficiency biomass dry powder pressurized fluidized bed gasification process system includes six process units: a biomass powder making unit, a biomass conveying unit, a biomass gasification and heat recovery unit, a synthesis gas purification unit, a slag water treatment unit, and a steam-water system unit.

[0031] The process flow of the gasification process system in this embodiment is as follows: (1) preparing the purchased biomass into dry biomass powder through a biomass powder making unit; (2) The biomass powder is transported to the biomass gasification and heat recovery unit by pneumatic conveying through the biomass conveying unit; (3) Biomass powder reacts with steam and oxygen in the biomass gasification and heat recovery unit to generate synthesis gas, achieving efficient heat recovery and completing the separation of coarse slag and most of the fine ash; (4) The syngas after heat recovery enters the syngas purification unit to further remove fine ash in the syngas before being sent to the next stage for use; (5) The slag water and black water in the process system enter the slag water treatment unit, where they undergo heat recovery, coarse slag separation, fine ash separation, ash water deoxidation, ash water preheating and other process steps before entering the process system for reuse; (6) The steam-water system unit is an auxiliary system of the biomass gasification and heat recovery unit. In this system, boiler feed water is exchanged with synthesis gas and heat is recovered. After the heat is recovered, high-pressure steam is generated in the steam-water system and sent out for use.

[0032] The biomass powder making unit is composed of a material feed bin 11, a material conveying device 12, a material tearing machine 13, a crushing conveying device 14, a material drying and powder making device 15, a powder conveying device 16 and related pipelines. The process flow is as follows: the baled biomass first enters the material feed bin 11, and then is sent to the material tearing machine 13 through the material conveying device 12 to tear the biomass material into crushed materials. The crushed materials are sent to the material drying and powder making device 15 through the crushed material conveying device 14. In the material drying and powder making device 15, the crushed materials are simultaneously biomass powdered and dried. The particle size range of the biomass powder is approximately 10μm to 200μm, and the water content of the biomass powder is approximately controlled at 2%~6%. The generated biomass dry powder is sent to the biomass conveying unit through the powder conveying device 16.

[0033] The material drying and pulverizing device 15 prepares the biomass fragments into powder by mechanical crushing. The device also has a drying function, and the drying method adopts an electric auxiliary heating method using green electricity.

[0034] The biomass conveying unit is composed of a powder storage bin 21, a powder pressure changing bin 22, a dispensing bin 23 and related pipelines, and its process flow is as follows: the biomass dry powder from the biomass milling unit first enters the powder storage bin 21 for standby, the biomass powder in the powder storage bin 21 is pressurized by the powder pressure changing bin 22 and then enters the dispensing bin 23, the material from the powder pressure changing bin 22 is discharged into the dispensing bin 23 and then the pressure is released and the powder is added again before the next addition to the dispensing bin, the dispensing bin 23 uses a carrier gas to pneumatically convey the biomass powder to the biomass gasification and heat recovery unit for gasification reaction.

[0035] The transporting carrier gas and pressurizing gas of the biomass transport unit are inert gases CO2 or N2. Preferably, in the process of biomass gasification to produce green methanol, CO2 is preferably used as the transporting carrier gas and pressurizing gas.

[0036] The biomass gasification and heat recovery unit is composed of a burner 31, a gasification chamber 32 of a gasifier, a gasification slag gas treatment chamber 33, a slag breaker 34, a slag discharge lock hopper 35, a gas pipeline 36, a convection waste pot 37, a circulation machine 38, a steam-oxygen mixer 1139 and corresponding pipelines. The burner 31 is fixed to the upper end of the gasification chamber 32 of the gasifier through a burner mounting port 322, the gasification chamber 32 of the gasifier is connected to the gasification slag gas treatment chamber 33 through the gasification chamber outlet 321, the slag breaker 34 is at the bottom of the gasification slag gas treatment chamber 33, 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.

[0037] The gasification chamber 32 of the gasifier includes a two-layer structure of an inner chamber 323 and an outer shell 324 .

[0038] The process flow is as follows: the superheated steam and oxygen premixed by the steam-oxygen mixer 39 are sprayed into the gasification chamber 32 of the gasifier together with the biomass powder from the biomass conveying unit through the burner 31 installed on the top of the gasifier to undergo a high-temperature gasification reaction. The reaction temperature in the gasification chamber is set to 2.8Mpa, and the gasification temperature is set to about 1300°C. The high-temperature synthesis gas that generates the synthesis gas flows from the gasification chamber outlet 321 of the gasifier from top to bottom into the gasification furnace slag gas treatment chamber 33. In the gasification furnace slag gas treatment chamber 33, the synthesis gas first recovers heat through the built-in radiation waste pot 333 to reduce the synthesis gas temperature to about 800°C, and then is mixed with the low-temperature synthesis gas withdrawn from the washing tower 42 by the circulation machine 38 and quenched to about 600°C to avoid the alkali metal contamination temperature section of the biomass ash, and then The synthesis gas continues to flow downward, and the coarse slag in the gasification furnace slag gas treatment chamber 33 of the synthesis gas falls directly into the water bath below due to gravity, and most of the fine ash is also separated from the synthesis gas and falls into the water bath under the action of the micro-cyclone separator 331. The separated synthesis gas is collected by the micro-cyclone annular gas collecting pipe 332 and discharged from the gasification furnace from the synthesis gas outlet 336, and then enters the convection waste boiler 37 through the gas supply pipe 36 to further recover heat and cool to about 260°C before being sent to the synthesis gas purification unit; the coarse slag and a small amount of fine ash separated in the gasification furnace slag gas treatment chamber 33 are crushed by the slag crusher 34 below it and fall into the slag discharge lock bucket 35, and are discharged into the slag water treatment unit 5 for treatment through the slag discharge lock bucket 35, while a large amount of fine ash enters the slag water treatment unit 5 for treatment along with the black water discharged from the gasification furnace slag gas treatment chamber 33.

[0039] The synthesis gas purification unit is composed of a gas-liquid mixer 41, a washing tower 42, a quenching water pump 43, and related auxiliary facilities. Its process flow is as follows: the synthesis gas carrying a small amount of dust from the convection waste boiler 37 first enters the gas-liquid mixer 41 and is mixed with the ash water extracted from the washing tower 42 by the quenching water pump 43. After the synthesis gas is humidified and the fine ash particles are agglomerated in the gas-liquid mixer 41, it enters the washing tower 42. The synthesis gas is first washed in a water bath in the washing tower 42, and then the synthesis gas is countercurrently contacted with the process condensate on the internal components of the washing tower 42 to achieve synthesis gas dust removal and purification, and the dust content in the synthesis gas is reduced to less than 1 mg / Nm³; in addition, a part of the ash water extracted from the washing tower 42 by the quenching water pump 43 enters the gasification furnace slag gas treatment chamber 33 for ash cooling.

[0040] The slag water treatment unit performs coarse slag separation, black water and gray water flash evaporation, fine ash separation, gray water deoxygenation, gray water preheating and other treatments on the ash in the unit, so as to achieve ash separation and gray water regeneration and recycling. The separated ash is transported out for disposal, and the regenerated gray water is preheated and pressurized before being sent back to the washing tower 42 for water replenishment of the washing tower 42.

[0041] The pressure and number of steam drums of the steam-water system unit are designed according to actual conditions. 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 radiation waste boiler 333 to generate high-pressure steam, and the high-pressure steam returns to the high-pressure steam drum 61 and 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 convection waste boiler 37 to generate medium-pressure steam, and the medium-pressure steam returns to the medium-pressure steam drum 63 and then enters the convection waste 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.

[0042] For the above gasification process system, Figure 2 As shown, the specific design of the biomass gasification and heat recovery unit is as follows: 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 bucket are longitudinally arranged and connected in sequence. The burner 31 is installed on 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.

[0043] The burner 31 is provided with two process medium channels, and the gasification furnace gasification chamber 32 and the gasification furnace slag gas treatment chamber 33 are manufactured in an integrated manner.

[0044] The gasification chamber 32 of the gasifier is a double-layer structure, including an inner shell 323 and an outer shell 324. In this embodiment, the inner shell 323 of the gasifier is a refractory brick structure, the gasification operating temperature is set to 1300°C according to the material characteristics, and the gasification pressure is set to 2.8Mpa according to the whole plant process.

[0045] The gasification furnace slag gas treatment chamber 33 is connected to the convection waste boiler through a gas pipeline, and the synthesis gas of the circulation machine is connected to the gasification furnace slag gas treatment chamber 33 in two ways. One steam output pipeline of the convection waste 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.

[0046] The gasification furnace slag gas treatment chamber 33 includes a radiation waste pot 333 in the middle and upper section and a slag water bath section in the lower section; the radiation waste pot is provided with a low-temperature synthesis gas intake purge route, a low-temperature synthesis gas intake cooling route, and a synthesis gas exhaust route.

[0047] The radiation waste boiler 333 is provided with a boiler feed water inlet 339 at the lower end, a boiler feed water outlet 3310 at the upper end, and two air curtain gas inlets 334 at the upper end. The heating surface of the radiation waste boiler 333 is provided with a group of annular air curtain soot blowing ports 3311 connected to the air curtain air inlet every 1 meter in the vertical space. The nozzle gas velocity range of the air curtain soot blowing ports 3311 is 15-45m / s. The top group of air curtain soot blowing ports 3311 uses the low-temperature synthesis gas from the circulation machine 38 for continuous air curtain blowing, and the other air curtain ports are intermittently purged, so as to ensure that the top high-temperature heating surface does not slag and the lower heating surface does not accumulate dust. The air curtain gas inlet 334 and multiple groups of air curtain soot blowing ports 3311 form a low-temperature synthesis gas inlet purge route.

[0048] The lower end of the radiation waste boiler 333 is provided with a quenching gas inlet 335. The low-temperature synthesis gas from the circulation machine 38 enters the annular quenching gas nozzle 3312 provided at the lower end of the radiation waste boiler 333 from the quenching gas inlet 335 and continuously sprays into the furnace to cool it down. The quenching gas nozzle gas velocity range is 5-30m / s, so that the synthesis gas is quenched and cooled to avoid the temperature range of alkali metal contamination. The micro-cyclone annular air collecting pipe 332 can be Figure 4 The structure composed of the entire circular tube shown in Figure 5 The structure is composed of two arc-shaped annular tubes. Figure 5As shown in the structure, a micro-cyclone annular air collecting pipe 332 composed of two semicircular ring tubes is arranged at the lower end of the radiation waste boiler 333 for collecting the synthesis gas after the ash is removed by the micro-cyclone separator 331. The micro-cyclone annular air collecting pipe 332 is connected to two synthesis gas outlets 336. A plurality of micro-cyclone separators 331 evenly distributed in a circular array are arranged at the lower end of the micro-cyclone annular air collecting pipe 332 to separate the synthesis gas from the fine ash. Here, the quenching air inlet 335 and the annular quenching air nozzle 3312 form a low-temperature synthesis gas intake cooling route.

[0049] The micro-cyclone separator 331, the micro-cyclone annular gas collecting pipe 332, and the synthesis gas outlet 336 form a synthesis gas discharge route. The synthesis gas separated by fine ash enters the subsequent convection waste boiler from the synthesis gas outlet 336 through two gas pipes 36; the lower end of the gasification furnace slag gas treatment chamber 33 is provided with a slag discharge port 337, and the lower end of the slag discharge port 337 is immediately installed with a slag breaker 34. The coarse slag produced by gasification passes through the water bath of the lower section of the gasification furnace slag gas treatment chamber 33 and enters the slag breaker 34. The lower section of the gasification furnace slag gas treatment chamber 33 is also provided with a quenching black water outlet 338, and the black water carrying a large amount of fine ash is discharged into the slag water treatment unit 5 through the quenching black water outlet 338.

[0050] like Figure 3 As shown, the micro-cyclone separator 331 is located at the end of the radiation waste pot 333 and is arranged in a circular array. The number of the micro-cyclone separators 331 is calculated based on the amount of synthesis gas. The inlet pipe of the micro-cyclone is preferably arranged at an angle parallel to the tangent of the circular circumference.

[0051] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A high-efficiency biomass dry powder pressurized entrained flow gasification process system, characterized by: It includes a biomass milling unit, a biomass conveying unit, a biomass gasification and heat recovery unit, a synthesis gas purification unit, a slag 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 materials are prepared into biomass dry powder by the biomass milling unit, and the biomass dry powder is transported 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 synthesis gas, which is then heat recovered to separate the coarse slag and fine ash. The syngas after heat recovery enters the syngas purification unit to further remove the unseparated fine ash in the syngas and then is sent to the next stage for use; The slag water and black water in the process system enter the slag water treatment unit (5), and after the steps of heat recovery, coarse slag separation, fine ash separation, ash water deoxidation, and ash water preheating are carried out in the slag water treatment unit (5), they enter the process system for repeated use; In the steam-water system unit, the boiler feed water is exchanged with the synthesis gas and the heat is recovered. After the heat is recovered, high-pressure steam is generated in the steam-water system and sent out for use.

2. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 1 is characterized in that: The biomass milling unit comprises a material feed bin (11), a material conveying device (12), a material tearing machine (13), a crushing conveying device (14), a material drying and milling device (15), a powder conveying device (16) and corresponding pipelines; the feed port of the material feed bin (11) is connected to a biomass raw material source, the discharge port of the material feed bin (11) is connected to a feed end of the material conveying device (12), the discharge end of the material conveying device (12) is connected to the feed port of the material tearing machine (13), the discharge port of the material tearing machine (13) is connected to the feed end of the crushing conveying device (14), the discharge end of the crushing conveying device (14) is connected to the feed port of the material drying and milling device (15), the discharge port of the material drying and milling 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 material first enters the material feed bin (11), and then is sent to the material tearing machine (13) through the material conveying device (12) to tear the biomass material into fragments. The fragments are sent to the material drying and powder making device (15) through the fragment conveying device (14). In the material drying and powder making device (15), the fragments are simultaneously subjected to biomass powder making and drying. The particle size range of the biomass powder is: 10μm~200μm, and the water content of the biomass powder is controlled at 2%~6%. The generated biomass dry powder is sent to 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 is characterized in that: The material drying and powder making device (15) uses a mechanical crushing method to prepare biomass crushed materials into powder, and dries the biomass powder at the same time; the drying uses electric auxiliary heating, steam auxiliary heating, or low oxygen content hot air drying.

4. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 2, characterized in that: The biomass conveying unit comprises a powder storage bin (21), a powder pressure-changing bin (22), a dispensing bin (23) and corresponding pipelines; the feed port of the powder storage bin (21) is connected to a material pipeline connected to the discharge end of the powder conveying device (16); the discharge port of the powder storage bin (21) is connected to the feed port of the powder pressure-changing bin (22); the discharge port of the powder pressure-changing bin (22) is connected to the feed port of the dispensing bin (23); and the discharge port of the dispensing bin (23) is connected to a biomass gasification and heat recovery unit; The process flow of the biomass conveying unit is as follows: the biomass dry powder from the biomass milling unit first enters the powder storage bin (21) for standby use; the biomass powder in the powder storage bin (21) is pressurized by the powder pressure changing bin (22) and then enters the dispensing bin (23); the material in the powder pressure changing bin (22) is discharged into the dispensing bin (23) and then pressure is released and the powder is added again to wait for the next addition of material to the dispensing bin; the dispensing bin (23) continuously delivers the biomass powder to the biomass gasification and heat recovery unit by means of pneumatic conveying with a carrier gas to cause a gasification reaction.

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

6. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 4 is characterized in that: The biomass gasification and heat recovery unit comprises a burner (31), a gasification furnace gasification chamber (32), a gasification furnace slag gas treatment chamber (33), a slag crusher (34), a slag discharge lock bucket (35), a convection waste boiler (37), a circulation machine (38), a steam-oxygen mixer (39) and corresponding pipelines; The burner (31), the gasification chamber (32) of the gasifier, the gasification slag gas treatment chamber (33), the slag breaker (34), and the slag discharge lock bucket (35) are arranged longitudinally and connected in sequence. The gasification slag gas treatment chamber (33) is connected to the convection waste boiler (37) through a gas transmission pipe (36). The synthesis gas of the circulation machine (38) is connected to the gasification slag gas treatment chamber (33) in two ways. One steam output pipeline of the convection waste 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 slag gas treatment chamber (33) includes a radiation waste boiler (333) in the middle and upper section and a slag water bath section in the lower section. The radiation waste boiler (333) is provided with a low-temperature synthesis gas intake purge route, a low-temperature synthesis gas intake cooling route, and a synthesis gas discharge route.

7. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 6 is characterized by: The radiation waste boiler (333) is provided with one or more boiler feed water outlets (3310) at the top of the shell, one or more boiler feed water inlets (339) at the lower end of the shell side wall, and one or more air curtain gas inlets (334) at the upper end of the shell side wall. The heating surface of the radiation waste boiler (333) is provided with multiple groups of annular air curtain soot blowing ports (3311) connected to the air curtain gas inlets (334) in the vertical space. The nozzle air velocity matching pressure of the air curtain soot blowing ports (3311) is set to be between 15 and 45 m / s. The air curtain soot blowing ports (3311) use the low-temperature synthesis gas from the circulating machine (38) to perform continuous or intermittent air curtain blowing to ensure that the heating surface is not slagging and dust accumulation. The air curtain gas inlet (334) and the multiple groups of air curtain soot blowing ports (3311) form a low-temperature synthesis gas intake and blowing route. The radiation waste boiler (333) is provided with a quenching air inlet (335) and a boiler feed water inlet (339) at the lower part of the shell side wall, and a synthesis gas outlet (336) is provided below the side wall below the quenching air inlet (335) and the boiler feed water inlet (339); an annular quenching air nozzle (3312) is provided in the radiation waste boiler (333) at a height corresponding to the quenching air inlet (335), and a micro-cyclone annular gas collecting nozzle (3312) is provided at a height corresponding to the synthesis gas outlet (336). A pipe (332) is provided, and a plurality of micro-cyclone separators (331) are evenly distributed at the lower end of the micro-cyclone annular air collecting pipe (332); the quenching air inlet (335) and the annular quenching air nozzle (3312) form a low-temperature synthesis gas intake cooling route, and the gas velocity of the quenching air nozzle (3312) is set between 5 and 30 m / s; the micro-cyclone separators (331), the micro-cyclone annular air collecting pipe (332), and the synthesis gas outlet (336) form a synthesis gas discharge route.

8. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 7 is characterized in that: The micro-cyclone separators (331) are located at the end of the radiation waste boiler (333) and are arranged in a circular array along the inner diameter of the furnace body. The number of micro-cyclone separators is calculated based on the amount of synthesis gas.

9. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 7 or 8, characterized in that: The micro-cyclone inlet pipe of the micro-cyclone separator (331) is preferably arranged at an angle parallel to the tangent line of the annular circle.

10. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 7 or 8, characterized in that: Designed according to the project implementation situation, the micro-cyclone annular gas collecting pipe (332) is a whole circular ring pipe structure, or is composed of two semi-circular ring pipes, or is composed of a structure composed of multiple sections of arc-shaped ring pipes, and each section of the ring pipe is provided with a corresponding synthesis gas outlet (336).

11. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 6, characterized in that: The burner (31) has a water-cooling protection structure and is provided with at least two process medium channels.

12. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 6, characterized in that: The gasification chamber (32) of the gasifier has a double-layer structure, including an inner shell (323) of the gasifier and an outer shell (324). The inner shell adopts a refractory brick structure or a water-cooled wall structure. The gasification operating temperature is 1200° C. to 1500° C., and the gasification pressure is 1.0 Mpa to 6.4 Mpa.

13. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 7, characterized in that: 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 (39) are sprayed together with the biomass powder from the biomass conveying unit through the burner (31) into the gasification chamber (32) of the gasifier to generate synthesis gas by a high-temperature gasification reaction. The high-temperature synthesis gas with a temperature of 1200°C to 1500°C flows from the outlet (321) of the gasification chamber of the gasifier into the gasification furnace slag gas treatment chamber (33) from top to bottom. In the gasification furnace slag gas treatment chamber (33), the synthesis gas first recovers heat through the built-in radiation waste pot (333) to reduce the synthesis gas temperature to 700°C to 850°C, and then is mixed with the low-temperature synthesis gas from the circulation machine (38) to be quenched to 500°C to 650°C to avoid the alkali metal contamination temperature section of the biomass ash, and then the synthesis gas continues to flow downward. The synthesis gas in the gasification furnace slag gas treatment chamber The coarse slag in (33) falls directly into the slag water bath section below due to gravity, and most of the fine ash is separated from the synthesis gas by the micro-cyclone separator (331) and falls into the water bath. The separated synthesis gas is collected by the micro-cyclone annular gas collecting pipe (332) and discharged from the gasifier from the synthesis gas outlet (336), and then enters the convection waste boiler (37) through the gas transmission pipe (36) to further recover heat and cool to 320°C~250°C before being sent to the synthesis gas purification unit; the coarse slag separated by the gasification furnace slag gas treatment chamber (33) and a small amount of fine ash that has not entered the micro-cyclone separator (331) are crushed by the slag crusher (34) below and fall into the slag discharge lock bucket (35), and are discharged into the slag water treatment unit (5) for treatment through the slag discharge lock bucket (35), while a large amount of fine ash enters the slag water treatment unit (5) for treatment along with the black water discharged from the gasification furnace slag gas treatment chamber (33).

14. 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) performs coarse slag separation, black water and gray water flash evaporation, fine ash separation, gray water deoxygenation, and gray water preheating treatment on the slag. After treatment, the separated ash is transported out for disposal, and the regenerated gray water is preheated and pressurized and then sent back to the synthesis gas purification unit for washing and replenishing water.

15. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 1 or 14, characterized in that: The synthesis gas purification unit comprises a gas-liquid mixer (41), a washing tower (42), a quenching water pump (43) and corresponding pipelines; The process flow of the synthesis gas purification unit is as follows: the scrubbing tower 42 obtains the scrubbing liquid source from the process condensate and the slag water treatment unit (5); the synthesis gas carrying a small amount of dust from the convection waste boiler (37) first enters the gas-liquid mixer (41) and is mixed with the ash water extracted from the scrubbing tower (42) by the quenching water pump (43); the synthesis gas is humidified in the gas-liquid mixer (41) and the fine ash particles are agglomerated before entering the scrubbing tower (42); the synthesis gas is scrubbed in the scrubbing tower (42) and then countercurrently contacts the process condensate in the scrubbing tower (42) to achieve dust removal and purification of the synthesis gas, thereby reducing the dust content in the synthesis gas to less than 1 mg / Nm³; at the same time, the ash water extracted from the scrubbing tower (42) by the quenching water pump (43) also enters the gasification furnace slag gas treatment chamber (33) through another pipeline to cool the ash.

16. The high-efficiency biomass dry powder pressurized entrained flow gasification process system according to claim 6, characterized in that: The steam-water system unit comprises 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 corresponding pipelines. As an auxiliary system of the biomass gasification and heat recovery unit, the process flow of the steam-water system unit is as follows: the high-pressure boiler circulating pump (62) sends the boiler feed water in the high-pressure steam drum (61) into the radiation waste boiler (333) to generate high-pressure steam, and the high-pressure steam returns to the high-pressure steam drum (61) and is then 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 convection waste boiler (37) to generate medium-pressure steam, and the medium-pressure steam returns to the medium-pressure steam drum (63) and then enters the convection waste boiler (37) again to generate superheated steam, a small amount of superheated steam enters the steam-oxygen mixer (39) and then enters the gasifier together with oxygen to react, and most of the superheated steam is sent to other users for use.

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