两步进气法和水蒸气对竹材下吸式固定床气化性能的影响

Experimental investigation of bamboo gasification in the double air stage downdraft fixed-bed gasifier using air and steam agent

以毛竹加工剩余物为研究对象,采用自制的两步进气下吸式固定床气化炉,在当量比(ER)一定的情况下,研究进气比例(AR,0%和60%)和水蒸气/生物质质量比(ms/mb,0,0.045,0.112,0.153,0.211,0.245和0.305)对气化炉性能(炉内温度分布、原料消耗率和气化强度)和可燃气指标(温度、成分、热值和焦油含量)的影响。结果表明:1)与一步进气法相比,两步进气法(AR为60%时)可显著提高气化炉炉温,并且分别在2个进气位置出现2个温度峰,分别为热解区的606℃和氧化区的856℃,可燃气的温度也增加至377℃; 2)两步进气法可显著提高可燃气的可燃组分含量和热值,降低焦油含量,CO含量、H_2含量和低位热值的最大值分别为17.47%、14.67%和4.54 MJ/Nm^3,焦油含量最低值为55.4 mg/Nm^3; 3)随着m_s/m_b从0.045增加至0.305,气化炉内各反应区的温度逐渐降低,与空气气化剂相比,虽然热值并未增加,但是可燃气中H_2和CO的含量发生变化,导致V(H_2)/V(CO)比例逐渐增加至1.01,有助于应用于合成气的研究。本研究为竹材废弃物的能源化利用提供了新的途径和基础数据。

In order to investigate the effect of double air intake method and steam agent on the performance of biomass downdraft fixed-bed gasifier fed by bamboo ( Phyllostachys edulis ) residues, two air ratios (AR, 0% and 60%) in double air intake method and six steam/biomass mass ratios (ms/mb, 0.045, 0.112, 0.153, 0.211, 0.245, and 0.305 ) were chosen. These parameters were used to study the performance of gasifier (temperature distribution, feedstock consumption rate, cold gas efficiency, carbon conversion rate, and gas production rate) and gas properties in gasifier (temperature, composition, heating value, and tar content). The result showed that:(1) Compared with the one air intake method, the double air intake method could remarkably promote the temperature inside the gasifier when the AR was 60%. Two temperature peaks were clearly observed in the pyrolysis zone (606℃) and combustion zone (856℃), and the gas temperature in the gasifier reached its maximum value of 377℃.(2) Compared with the one air intake method, the double air intake method could remarkably promote the concentrations of combustible gas component and lower heating value (LHV) and reduce the content of tar when the AR was 60%. The maximum concentration of CO and H2 was 17.47% and 14.67%, respectively, and the minimum value of tar content was 55.4 mg/Nm^3 .(3) As the ms/mb increased from 0.045 to 0.305,the temperature inside the gasifier decreased. In contrast to the air agent, although only slight variation of the LHV of gas in gasifier was observed, the concentrations of H2 and CO were greatly varied, leading to an increase in ratio of V(H2)/V(CO) with 1.01. This result was beneficial for the application of produced gas on the field of synthesis gas. This research created a new industrial and energy application method for bamboo residues, and provided some basic data for bamboo gasification.