我国每年林业废弃物和农业生产剩余物质产量高达7亿t，如何有效利用这一巨大资源，已成为摆在科研工作者面前的重要课题。生物质气化技术改变了直接燃烧生物质的利用方式，提高了废弃生物质的能源品位，对节约常规能源、降低环境污染、保护生态环境具有重要意义。
Every year in our country forestry waste and surplus of agricultural production material production up to 700 million t, how to effectively utilize the huge resources, has become an important topic in front of scientific research workers. Biomass gasification technology changed the way direct combustion biomass utilization, improve the grade of waste biomass energy, to save conventional energy, reduce environmental pollution, protect the ecological environment is of great significance.
下吸式固定床气化炉由于具有结构简单，易于操作，产出气焦油含量低等优点已经得到了广泛的应用。生物质气化过程是一个复杂的热化学反应过程，生物质气化炉各部位结构尺寸将极大地影响气化炉的热效率、产气成分和产气品质,故设计合理的生物质气化炉是有效利用生物质能的关键。
Suction under the fixed bed gasifier with simple structure, easy to operate, the output gas low tar content advantages has been widely used. Biomass gasification process is a complex thermal chemical reaction process, each part of the biomass gasifier structure size will greatly affect the thermal efficiency of gasifier, gas composition and gas quality, so the reasonable design of biomass gasifier is the key to effective utilization of biomass energy.
作为气化剂的空气从气化炉侧壁空气喷嘴吹入，其产出气的流动方向与物料下落的方向一致，故下吸式气化炉也称为顺流式气化炉。吹入的空气与物料混合燃烧，这一区域称为氧化区，温度约为900～1200℃，产生的热量用于支持热解区裂解反应和还原区还原反应的进行；氧化区的上部为热解区，温度约为300～700℃，在这一区域，生物质中的挥发分（裂解气、焦油以及水分）分离出来；热解区的上部为干燥区，物料在此区域被预热；在氧化区的下部为还原区，氧化区产生的CO2和碳、水蒸气在这一区域进行还原反应，同时残余的焦油在此区域发生裂解反应，产生以CO和H2为主的产出气，这一区域的温度约为700～900℃。由于来自热解区富含焦油的气体须经过高温氧化区和以炽热焦炭为主的还原区，气体中的焦油在高温下被裂解，从而使产出气中的焦油大为减少。
As the gasification agent of air blowing in from the gasifier wall air nozzle, the whereabouts of the output direction of gas flow and material in the same direction, so the suction under gasifier is also referred to as forward gasifier. Blow into the air and material mixed burning, an area known as the oxidation zone, the temperature is about 900 ~ 1200 ℃, the heat generated by the support area pyrolytic cracking reaction and reduction of area reduction reaction; Oxidation zone of the pyrolysis zone, the temperature is about 300 ~ 700 ℃, in the area, the biomass of volatile (cracking gas, tar, and moisture) isolated; Pyrolysis of upside for arid region, the material in this area is hot; At the bottom of the oxidation zone to reduction zone, area of CO2 and carbon oxide, water vapor in the region to carry on the reduction reaction, and the tar cracking reaction in this area, the residual gas output is given priority to with CO and H2, the temperature of this area is about 700 ~ 900 ℃. Area rich in tar from pyrolysis gas after high temperature oxidation zone and reduction zone, mainly for the hot coke tar cracking under high temperature in the gas, which has greatly reduced gas output in the tar.
由于生物质物料的堆比重、粒度相差较大，这将明显影响物料在炉内的驻留时间，这就要求气化炉因物料不同而选用差别较大的气化强度。对于堆比重较小或粒度较小的物料，其炉内驻留时间短，气化强度应相应减小；反之，应增大气化强度。一般气化强度推荐值为500～2000kg/（h·m2）。
As a result of the biomass material bulk density, particle size is large, it will significantly influence the dwell time of the material in the furnace, which requires a greater difference between gasifier with different materials to choose gasification intensity. For small bulk density or smaller particle size material, the furnace resides within short time, gasification intensity should be reduced accordingly; On the other hand, should increase the intensity of gasification. General gasification intensity recommended value for the 500 ~ 2000 kg/h · m2).
划词
尽管下吸式气化炉产出气中焦油含量很少，但根据产出气的不同应用场合，还应当配置不同的除焦油设备以及除尘、除湿设备以进一步提高产出气的品质。
Although the little suction gasifier tar content in the gas output, but according to the different applications of gas output, should also configure different except the tar and dust removal equipment, dehumidification equipment to further improve the quality of the output gas.
