Search

CN-121975555-A - Novel biomass circulating fluidized bed gasifier device and method

CN121975555ACN 121975555 ACN121975555 ACN 121975555ACN-121975555-A

Abstract

The invention provides a novel biomass circulating fluidized bed gasifier device, belongs to the technical field of biomass energy gasification conversion, and aims at the defects of complex structure, low gasification efficiency and the like of the existing circulating fluidized bed; the biomass gasification device comprises a novel biomass fluidized bed cyclone gasifier, a gasification cooling chamber, a gasification fly ash returning device, a fly ash cooling buffer bin, a feeding preheating dryer and a gasification air preheater, wherein during use, the biomass fluidized bed cyclone dust removal returning device is adopted to concentrate in a furnace body to realize internal circulation and external circulation of biomass gasification fuel, the fluidized bed structure is simplified, the cyclone in a dilute phase region is efficiently separated to improve the biomass carbon conversion efficiency, meanwhile, the temperature in the dilute phase region is improved to be beneficial to tar cracking, the gasification cooling chamber is cooled by steam, the steam is heated by fuel gas to be used for drying biomass feeding, and water-cooling steam is generated to condense and heat primary air of the gasifier, so that the biomass gasification efficiency is improved.

Inventors

  • LIU FANGLIANG
  • LIU JIA

Assignees

  • 武汉方程能源有限公司

Dates

Publication Date
20260505
Application Date
20260313

Claims (7)

  1. 1. The novel biomass circulating fluidized bed gasifier device is characterized by comprising a novel biomass fluidized bed cyclone gasifier (1), a gasification cooling chamber (2), a fly ash returning device (3), a fly ash cooling buffer bin (4), a feeding preheating dryer (5), a gasification air preheater (6), a high-pressure gasification fan (7) and a water vapor circulating cooling fan (8); The novel fluidized bed cyclone gasifier (1) is divided into a cyclone dilute phase region (1.1), a transitional inner jacket necking cyclone region (1.21), a dense phase region (1.2) and a wind distribution combustion chamber (1.3) from top to bottom. The swirl dilute phase zone (1.1) is internally provided with a steam cooling film wall (1.4), a plurality of groups of secondary air nozzles (1.5) and a steam connecting pipe (1.6). An inner protective cylinder (1.7), a rotational flow guide vane (1.8), a steady flow body (1.9) and a feeding spiral auger (1.10) are arranged in the middle of the dense phase zone (1.2). The bottom of the air distribution combustion chamber (1.3) is provided with a burner (1.11), an air distribution plate (1.12), a fluidized bed hood (1.13) and a return annular nozzle (1.14), and the bottom of the air distribution combustion chamber is provided with a slag discharge pipe; The gasification cooling chamber (2) is divided into an upper-level tube type heat exchanger (2.1), a lower-level tube type heat exchanger (2.2) and a steam soot blower (2.3) from top to bottom; the fly ash returning device (3) consists of an ash dropping pipe, a first fluidizing air chamber (3.1) and a second blanking air chamber (3.2); the fly ash cooling and buffering bin (4) consists of a fly ash buffering bin body air pipe (4.1), a bin body lower cooling water pipe (4.2) and a water-cooling spiral ash conveyer (4.3); The feeding preheating dryer (5) consists of a middle jacket shell (5.1) with a streaming fin and an inner screw shaft (5.2); the gasification air preheater (6) consists of a steam tube bundle and an air side air duct; The top of the novel circulating fluidized bed cyclone gasifier (1) is connected with a gasification cooling chamber (2) through a high-temperature pipeline; The gas pipeline of the gasification cooling chamber is connected with a gas external supply user pipe at the lower part of the gasification cooler. The raw material bin is connected with a feeding preheating dryer (5), a discharge hole of the feeding preheating dryer is connected with an intermediate bin (5.3), and the intermediate bin is connected with a feeding spiral auger (1.10). The rotational flow circulating fly ash of the circulating fluidized bed flows into the fly ash returning device (3) through a space ash falling pipeline between the inner protective cylinder (1.7) of the dense phase zone and the wall of the dense phase zone. The fly ash flows into the fly ash cooling buffer bin (4) by blowing fluidized air under the fly ash returning device. After passing through the cooling pipe at the lower part of the buffer bin, the air is sent out of the furnace through a water-cooling spiral ash conveyor (4.3), is sent into a gasification air preheater (6) by a blower (7), exchanges heat, is then introduced into a lower combustion chamber (1.11) of the hearth, and is sent into the gasification furnace through an air distribution plate.
  2. 2. The novel circulating fluidized bed gasifier device according to claim 1, wherein a gas diffusing ignition port, carbon monoxide (9) and an oxygen analyzer (10) are arranged on a gas pipeline at the outlet of the gas cooling chamber, and the gas components in the system are detected and controlled together by the carbon monoxide analyzer (9) and the oxygen analyzer (10) on the gas pipeline to regulate the feeding and air quantity in the system.
  3. 3. The novel circulating fluidized bed gasifier device according to claim 1, wherein the shell side of the upper-level tube array heat exchanger of the gas cooling chamber (2) is connected with an outlet pipe of the steam circulating fan (8), the outlet pipe enters the upper-level tube array heat exchanger for heat exchange together with cooling water fed by the cooling water pump (11), the upper-level tube array heat exchanger is connected with the lower-level tube array heat exchanger, and an outlet pipe shell side outlet of the lower-level heat exchanger is connected with an inlet of the steam circulating fan (8). Meanwhile, one side of the upper-level tube nest heat exchanger is provided with a steam outlet valve (2.4) for steam for the circulating fluidized bed gasification furnace.
  4. 4. The novel circulating fluidized bed gasifier device according to claim 1, wherein the shell side of the superior tubular heat exchanger is connected with a steam outlet pipe, and the outlet steam pipe is connected with a novel circulating fluidized bed cyclone dilute phase region air-cooled film type wall (1.4) and a plurality of groups of secondary air nozzles (1.5) through valves.
  5. 5. The novel circulating fluidized bed gasification furnace device according to claim 1, wherein a high-temperature steam outlet pipe of a novel fluidized bed cyclone dilute phase region steam cooling film wall (1.4) is connected with an interlayer (5.1) in a feeding preheating dryer (5), and the other pipe is connected with an intermediate bin (5.3). The outlet pipe of the interlayer heater (5.1) in the feeding preheating dryer (5) is connected with the steam outlet pipe of the other path of the interlayer heater and the steam outlet pipe of the intermediate storage bin (5.3) and then is integrated into the gasification air preheater (6). The heated air outlet pipe of the gasification air preheater is connected into an air combustion chamber (1.3), and the air combustion chamber (1.3) is provided with a gas burner (1.11).
  6. 6. The novel circulating fluidized bed gasifier device according to claim 1, wherein the novel circulating fluidized bed cyclone circulating fly ash is connected into a first fluidized air chamber (3.1) and a second blanking air chamber (3.2) in a fly ash returning device (3) through a space pipeline between a dense-phase zone inner protective cylinder and a dense-phase zone inner furnace body, a second blanking air chamber inclined pipe is connected into a buffering bin body (4), an air nozzle pipe (4.1) is arranged in the middle of the buffering bin body, a lower cold serpentine pipe group (4.2) is arranged at the lower part of the buffering bin body, and a water-cooling spiral ash conveyer (4.3) is connected below the buffering bin body.
  7. 7. The method for using the novel circulating fluidized bed gasifier device according to any one of claims 1 to 6, which is characterized by comprising the following steps of firstly preheating to enable the feeding temperature of the bed material on the air distribution plate (1.12) in the biomass gasifier (1) to be above a set temperature, and ensuring that the bed material in the gasifier (1) is fluidized normally. And (3) starting a biomass spiral feeder to feed a set raw material amount to the biomass gasification furnace, simultaneously starting a cooling water supply pump and a steam circulating fan to cool biomass fuel gas to a set temperature, adjusting a steam outlet valve to enable proper steam amount of drying steam fed to a feeding preheating dryer and an intermediate bin, starting a return air amount in a fly ash returning device (3), and finally starting a water-cooling spiral ash conveyer (4.3) to discharge ash for outward transportation. Biomass materials are produced by a dense-phase region in a gasification furnace (1) to generate high-temperature biomass gas which entrains biomass carbon powder, the high-temperature biomass gas is sent to a dilute-phase region after being subjected to cyclone flow through a dense-phase region cyclone guide vane (1.8), a plurality of groups of secondary air and steam are sprayed to generate high-temperature cyclone tar for decomposition in the dilute-phase region, fly ash falls into an outer interlayer of a jacket (1.7) of the dense-phase region, the fly ash is introduced through annular return air (1.14), the fly ash is recycled, the conversion rate of biomass gasified carbon is improved, the biomass gas is input into a gas cooling chamber (2) through a high-temperature pipeline at the top of the furnace, an air pipeline is arranged at the top of the gas cooling chamber (2), the introduced air is further heated to improve the tar decomposition rate, the high-temperature biomass gas is introduced into the outside the gasification furnace through a gas pipeline at the bottom of the gas cooling chamber after being cooled by a tube heat exchanger at the upper part and the lower part of the gas cooling chamber, and when the heat exchange capacity of the biomass gasification furnace is poor and the temperature is increased, and the fly ash is fully distributed on the tube heat exchanger, a rotary soot blower (2.3) is opened for regular soot blowing.

Description

Novel biomass circulating fluidized bed gasifier device and method Technical Field The invention belongs to the technical field of biomass energy gasification conversion, and particularly relates to a circulating fluidized bed gasification furnace system. More particularly, the invention relates to an innovative high-efficiency gasification furnace system which is integrated and operated in a furnace by integrating an internal solid cycle and an external cycle, has simplified equipment, realizes nearly complete conversion of carbon, has extremely low tar content in synthesis gas, and can flexibly adapt to various fuels. Background In recent years, due to the promotion of factors such as rapid economic development, price fluctuation of fossil energy, global climate change and the like, biomass can be listed as a real renewable energy source, has the characteristics of large potential, reproducibility and low pollution, and is internationally recognized zero-carbon energy without increasing the total amount of atmospheric greenhouse gases. Compared with renewable energy sources such as wind power, photovoltaic solar energy and water energy, the solar energy and water energy hybrid power generation system has the characteristics of stability and controllability. From the environmental point of view, biomass belongs to clean energy, has the characteristics of low ash, low sulfur and the like as fuel, and realizes a zero emission mechanism in combustion, and carbon dioxide after combustion participates in carbon circulation, so that new pollution is not formed. Development of biomass energy utilization technology is of great importance. In recent years, various countries in the world have put into much effort in biomass energy conversion, and research results of developing biomass energy to utilize new technologies and applications in biomass direct combustion, biomass briquette fuel, biomass pyrolysis, fuel ethanol, biodiesel and the like in China are remarkable. However, only a few exemplary devices for converting biomass gasification into chemical products actually put into operation. The biomass is not converted to a scale, and the main difficulties include low energy density of raw materials, various and complex physical properties, difficult collection, storage and transportation, difficult fuel transportation in equipment, tar problem, low conversion rate, poor economy, lack of product standards and the like. The circulating fluidized bed gasification technology is a key technology for converting solid fuel (such as coal, biomass, petroleum coke and organic waste) into clean synthesis gas (the main components of the technology are CO and H 2、CH4) as an advanced gasification conversion technology. The synthesis gas can be used for generating power, producing hydrogen, synthesizing liquid fuel and chemicals, and is one of core ways for realizing efficient and clean utilization of carbon resources. However, in the commercialized application process of the existing circulating fluidized bed gasification furnace with large scale, high efficiency and low cost, a series of technical bottlenecks which cannot be solved well for a long time still exist, the carbon conversion rate and gasification efficiency are low, the tar content in biomass gas is high, the gas heat value is low when the biomass water content is high, the air tightness is poor when gasification is carried out, and the existing furnace is complex and high in cost. Because of the contradiction between the gasification reaction rate and the particle residence time, the primary cyclone separator has low separation efficiency on small particles, a large amount of fine particle fuel is carried out of the hearth by high-speed airflow after entering the high-temperature reaction zone, and the carbon content in fly ash is usually up to 10% or even more than 20% because the fine particle fuel cannot be collected in the primary cyclone separator and leaves the gasification system. This not only reduces the gasification efficiency (cold gas efficiency is typically less than 76%), resulting in fuel waste. The restriction of tar problem is that tar is a mixture of macromolecular condensable hydrocarbon substances generated in the gasification process. The tar yield is large when gasifying at medium-high temperature (650-700 ℃), especially when gasifying and condensing biomass. They can condense in downstream equipment piping, causing plugging, corrosion and catalyst poisoning, one of the biggest obstacles to commercial application of gasification technology. The existing solutions such as high-temperature gasification (> 1100 ℃) have severe requirements on furnace materials, the investment and operation cost of catalytic cracking equipment outside the furnace are high, fly ash is easy to melt wall built-up and block gasification channels, and the thermal cracking energy consumption is huge. The contradiction between fuel adaptability, load regulation and stabi