Numerical Simulation Of Fluidized Bed Experimrntal Setup Under Oxy-enriched Atmosphere

Carbon dioxide occupies an important position in the greenhouse gases, whichcomes mainly from the burning of fossil fuels. Because coal-fired power plants are animportant source of CO₂emissions, reduction and control of CO₂from plant to alleviatethe greenhouse effect have a great significance. Fluidized bed oxy-fuel technology has agreat value for CO₂capture.The research on the fluidized bed under oxy-fuel technology is not mature now, inorder to grasp the technology better, this paper establishment a one-dimensionalsemi-empirical model which is related to the boiler’s characteristics. Through theprogramming which is written in Fortran language, a series of sub-models made up theoxy-fuel fluidized bed comprehensive mathematical model was established, whichincluded hydrodynamic、combustion and heat transfer characteristics of the fluidizedbed. Then established gas、solids mass balance and energy balance to each chamber,simulate the temperature distribution, the heat exchange coefficient distribution, andconcentration profiles under different combustion atmosphere.This paper established the model which can simulate the combustion of fluidizedbed with thermal power of10KW. Firstly, we do a series of experiments about fluidizedbed on the atmosphere of air and30%O₂/70%CO₂, then do the comparison of resultfrom numerical simulation and experimental, the comparison validate the reliability ofthe model to some extent. Secondly, the comparison of the fluidized bed under the airand21%O₂/79%CO₂atmosphere was done, we can concluded that it is easy to capturethe CO₂from the exhaust gas when use CO₂replaced the N2, there is also higher COconcentration in21%O₂/79%CO₂atmosphere. Finally, maintained the same amount ofcoal and the air volume, though changing the concentration of O₂（20%O₂/80%CO₂、30%O₂/70%CO₂、40%O₂/60%CO₂） to simulate the fluidized bed under differentatmosphere. The results showed that: when in the same amount of coal, the higherconcentration of O₂, the higher temperature at the bottom of the furnace, but the furnaceat the top of the opposite trend, the trend of heat transfer coefficient at the bottom wassame with the temperature, while the highest heat transfer coefficient was in the30%O₂/70%CO₂atmosphere; When given the same amount of wind, the higherconcentration of O₂, the higher furnace temperature, and the temperature distributionwas more uniform, the furnace heat transfer coefficient distribution was consistent withthe temperature trends.