Abstract

Reducing the CO content and improving the lower heating value (LHV) of biomass producer gas are essential for transforming it into a reliable energy source. The present work strives to provide a simulation perspective for a biomass producer gas upgrading process containing integrated shift-methanation and cyclic CO₂ capture, where the CO₂ by product from the shift-methanation reactor is separated by cyclic mono-ethanolamine (MEA) scrubbing. Equilibrium calculations via the Gibbs energy minimization method reveal that the appropriate temperature and pressure window for the shift-methanation reaction is 300–450 °C and 1–5 bar, respectively. The simulation results show that the optimal stage number for both the absorber and stripper is 10. The desired value of absorber and stripper efficiency can be obtained by balancing the MEA flow rate and reboiler duty. The original biomass producer gas with a 44.4% CO content and LHV of 9.45 MJ/Nm³ is upgraded to a CO content below 10% and LHV over 14 MJ/Nm³, reaching the national classification standard of Grade I gas. The preliminary engineering design in this work combines the shift-methanation reaction with CO₂ absorption–desorption, demonstrating much potential for industrial-scale applications.

摘要

降低 CO 含量和提高生物质发生炉煤气的低热值 (LHV) 对于将其转化为可靠的能源至关重要。目前的工作致力于为包含集成变换甲烷化和循环 CO ₂捕获的生物质生产气体升级过程提供模拟视角，其中 CO ₂来自变换甲烷化反应器的副产物通过环状单乙醇胺 (MEA) 洗涤分离。通过 Gibbs 能量最小化方法进行的平衡计算表明，变换-甲烷化反应的合适温度和压力窗口分别为 300–450 °C 和 1–5 bar。模拟结果表明，吸收塔和汽提塔的最佳级数均为 10。吸收塔和汽提塔效率的期望值可以通过平衡 MEA 流量和再沸器负荷来获得。CO含量为44.4%、LHV为9.45 MJ/Nm ³的原始生物质发生炉煤气升级为CO含量低于10%、LHV超过14 MJ/Nm ³，达到国家一级燃气分类标准。这项工作的初步工程设计将变换-甲烷化反应与CO ₂吸收-解吸相结合，展示了工业规模应用的巨大潜力。