串行流化床生物质气化动力学模拟

生物质是一种清洁、可再生能源,来源广泛。串行流化床气化工艺将生物质气化和燃烧过程分离,具有气化温度较低和合成气浓度高等优点,是国内外学者进行生物质能源利用研究的热点之一。为模拟其气化过程,针对松木和玉米秸秆这2种生物质原料,以水蒸气为气化介质,结合气化反应动力学方程,利用Aspen Plus系统(V7.2)对串行流化床生物质气化过程进行了动力学模拟,考察了进料水蒸气与生物质质量比(S/B)和气化温度对气化干气组成和产率的影响。模拟结果表明:①S/B值的变化、气化湿度的变化对松木和玉米秸秆气化所得干气组成及产率的影响趋势是一致的,但随着S/B增加,松木和玉米秸秆气化所得干气产率增加,CO_2和H_2含量升高,CO含量降低;②随着气化温度的升高,干气中H_2和CO_2含量逐渐降低,CO含量和干气产率增加;③在相同研究条件下,松木气化所得干气中的H_2含量与玉米秸秆气化相当,但产率优于玉米秸秆气化的产率。

Kinetic modeling of biomass gasification in interconnected fluidized beds

Biomass is a kind of clean and renewable energy with a huge distribution across the land. An interconnected fluidized bed gasification process separates the biomass gasification from combustion, with low gasification temperature and highly concentrated syngas, which has received great. In this paper, pines and corn stalks were selected as biomass feedstock and steam was employed as a gasification medium. The kinetic model for the biomass gasification in an interconnected fluidized bed was generated and developed in Aspen Plus V7.2. Sensitivity analysis was conducted to examine the effect of steam biomass ratio (based on mass) S/B and gasification temperature on the dry gas molar composition and yield. The results show that the change in S/B value and gasification temperature had similar influences on the variation trend of dry gas composition and yield of pines and corn stalks. The dry gas yield, H₂ and CO₂ molar concentrations increase and the CO concentration decreases with the increase of S/B value. Along with the increase of gasification temperature, the content of H₂ and CO₂ progressively lowers, while the content of CO and dry gas yield increase. Under the same research conditions, the content of H₂ in dry gas from pine gasification is similar to that from corn stalk gasification, while the dry gas yield of the former is better than that of the latter.