Process stability verification of the two-stage fluidized bed gasification for pine particles to produce clean gas
In order to verify the long-term operation stability of the two-stage fluidized bed gasification process,commercial fruit charcoal semi-coke is used as the catalytic bed material for the preparation of clean gas by pine fluidized two-stage gasification in this experiment.In the early stage of the experiment,a stable and effective catalytic semi-coke bed layer is formed to reduce the accumulation period of semi-coke,so as to quickly reach high-efficiency tar removal in the system.The excess air coefficient(ER)is maintained at 0.35,the gas velocity in the riser is 3m/s,and the oxygen concentration in the fluidization medium is gradually adjusted to gradually increase the biomass processing capacity.The results show that as the feed rate of pine particles increases from 1kg/h to 3kg/h,the volume percentages of CO and H2 in the product gas increase from 7.71%and 3.13%to 16.15%and 12.60%,respectively,while the volume percentage of CH4 slightly decreases.The gas yield also increases from 0.90m3/kg to 1.36m3/kg,and the corresponding calorific value of the product gas increases from 3.26MJ/m3 to 4.80MJ/m3.Through multiple manual start-stop and change of operating parameters,during the entire 12h operating cycle,the semi-coke produced by the fluidized two-stage gasification matches the speed of semi-coke consumption,and the temperature and pressure show good operating stability.This result proves that the two-stage fluidized bed gasification process has technological advancement and long-term operation stability in the production of gas from biomass.