Steady state kinetic model for entrained flow CO gasification of biomass at high temperature
Steady state kinetic model for entrained flow CO gasification of biomass at high temperature
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DOI：
10.1016/j.energy.2020.117073
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发表时间：
2020-04
期刊：
影响因子：
9
通讯作者：
M. Kibria;Pramod Sripada;S. Bhattacharya
中科院分区：
文献类型：
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作者：
M. Kibria;Pramod Sripada;S. Bhattacharya
气流床气化技术因其独特的性质被认为是一项有前途的技术；利用固体燃料生产高价值产品，停留时间短，碳转化率高，污染物排放少。在两级干进料气流床气化炉中，CO2 是从燃烧区逸出的主要气体种类，在氧气和空气燃烧气化炉中浓度分别约为 77% 和 18%。富含CO 2 的气流在还原区中充当反应物，产生合成气。本文提出了模拟干进料气流床反应器还原区的生物质 CO2 气化动力学模型。该模型基于热质量平衡的活塞流模拟。进行显式计算以计算颗粒停留时间。介绍了气相反应，并将预测结果与实验室规模的气流床反应器进行了比较。结果表明在高温CO2气化条件下；气相化学以均相逆水煤气变换反应（rWGSR）为主。颗粒结构通过在炭转化过程中施加扩散效应而发挥重要作用。增加二氧化碳浓度有双重目的：提高脱挥发分速率并降低扩散限制。
Entrained flow gasification technology is considered as a promising technology for its unique nature; high carbon conversion in short residence time and fewer pollutants emission for utilizing solid fuels towards high-value products. In a two-stage dry feed entrained flow gasifier,CO2is the predominant gas species that evolves from combustion zone with a concentration around 77% and 18% during oxy and air-fired gasifier respectively. TheCO2rich gas stream acts as a reactant in the reduction zone that produces syngas. This article presents a kinetic model ofCO2gasification of biomass that mimics the reduction zone of a dry feed entrained flow reactor. The model is based on plug flow analogy for heat and mass balance. Explicit calculations are performed to calculate particle residence time. Gas-phase reactions are introduced, and the predicted results are compared against a bench-scale entrained flow reactor. The results indicate during high-temperatureCO2gasification condition; the gas-phase chemistry is dominated by the homogenous reverse water gas shift reaction (rWGSR). Particle structure plays an essential role by imposing diffusional effects during char conversion. An increased concentration ofCO2served a dual purpose: raising devolatilization rate and lowering the diffusional limitation.