| Biomass gasification technology is one of the biomass utilization technology. Based on pyrolysis and combustion decoupling in biomass thermo-chemical conversion process, cyclone air staged composite gasification technology is put forward. This technology can effectively solve the problem in the cyclone gasification technology such as the short time of effective response, unreasonable air flow, the maldistribution of temperature field boundary, the low calorific value gas. it can improve the reaction more sufficiently.This topic perfects the staged composite cyclone air gasification experiment system. it is composed of the cyclone furnace reactor main body, the feeding system and air supply system, besides it includes char filled structure and secondary cyclone separating structure. On this experimental system, for the problems as the initial combustion and gasification temperature is low, the furnace combustion instability, it has carried on furnace process optimization of the experiment system. the experiments apply double feeding combustion process and the combustion process with rice husk quantificationally was 8.62kg/h, ER is 0.75,the ratio of primary air, secondary air, bottom air is respectively 0.48、0.14、0.38, can get a high heating rate, stable heating process and higher final temperature, good repeatability furnace process.In this experiment system, it studies the cyclone air staged composite gasification of rice husk, and explores the effect of the proportion of the bottom air in the rice husk cyclone air staged composite gasification under the invariant ratio of the bottom air. The research shows that the rate of the bottom air at 0.4-0.6 range changes, with the reduction of the ratio of the bottom air, the volume percentage of CH4 increases from 2.607% to 3.185%, C2H4 increases from 1.030% to 1.314%, C2H2 increases from 0.080% to 0.122%, C2H6 increases from 0.074% to 0.168%, H2 increases from 2.493% to 3.912%, CO increases after the first then decreases between 19.117% to 21.780%, and reachs maximum when the ratio the bottom air is 0.50. When the ratio of primary air, secondary air, bottom air is respectively 0.3、0.3、0.5,it can obtain better effects of gasification, the tar content is 3.240 g/Nm3, gas production rate of 1.294 Nm3/kg, carbon conversion and gasification efficiency are 71.5% and 50.8% respectively. In addition, through char catalyst filling in the gas outlet, it studies the effect of char catalytically cracking tar. The experiment indicates that char removal rate increases first and then decreases with the increase of gas outlet temperature. When the temperature of the gas outlet reaches 748 ℃(i.e., the ratio of secondary air is 0.20),the maximum of tar removal ratio is 68.58%.Steam-air gasification is the direction of the cyclone gasification. For providing theoretical basis of the process parameters optimization of steam gasification in the cyclone gasifier, steam gasification of gasification char is studied in the fixed/fluid bed. The study found that the temperature within the scope of 700℃ to 900℃, the weightlessness rate of gasification char secondary gasification increases first and then decreases with temperature increasing, the maximum is 29.56% in 850℃. By FTIR and Raman, it analyzes the functional group of the secondary gasification char under different temperature, the analysis found the oxygen containing functional groups, lipids functional groups, C=C in FTIR, and and total peak area in Raman are reduced. The ratio of D/G increases first then decreases, the ratio of D/(GR+VL+VR)is increasing and the ratio of S/G is decreasing. When the gasification temperature is 800 ℃, the steam gasification effect is most obvious. it show that the steam gasification can further promote air gasification. it provides theoretical basis of the process parameters optimization of steam gasification in the cyclone gasifier... |
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