生活垃圾与生物质共热解气化过程的模拟及优化

Simulation and Optimization of Co-Pyrolysis Gasification Process of Municipal Solid Waste and Biomass

摘要: 基于Aspen Plus平台，从热平衡角度出发，结合Gibbs自由能最小化原理，模拟了生活垃圾与生物质共热解气化工艺。利用实验数据与模拟结果比较，证明了该模型可用于共气化特性预测。进一步进行了灵敏度分析，研究了不同操作条件对共气化特性的影响，结果表明：生活垃圾占比减小，气体热值和干气产率降低，气化效率提高；气化温度在750℃以前对模拟结果影响很大；水蒸气流量在0.1 kg·h⁻¹ 时气化效率最高；氧气流量增加对模拟结果产生负面影响。通过总结各指标变化规律，得到了适宜的操作条件：原料混合比例取50:50，气化温度取750℃，水蒸气流量取0.1 kg·h⁻¹ ，氧气流量取0.005 kg·h⁻¹ 。在该条件下运行模拟，优化了模拟结果：合成气中H₂为54.43%，CO为33.23%，CO₂为11.77%，CH₄为0.57%，低位热值为10.27 MJ·Nm⁻³ ，干气产率为1.26 N m³ ·kg⁻¹ ，气化效率为70.10%。

Abstract: Based on Aspen Plus platform, from the angle of heat balance, combined with the principle of free energy minimization, the co-pyrolysis gasification process of MSW (municipal solid waste) and bio-mass was simulated. By comparing the experimental data with the simulation results, it is proved that the model can be used to predict the characteristics of co-gasification. The effects of different operating conditions on gasification characteristics were studied by sensitivity analysis. The results show that the proportion of municipal solid waste has decreased, the calorific value and dry gas yield of gas are reduced, and the gasification efficiency is improved. Gasification temperature has great influence on simulation results below 750˚C. The gasification efficiency is the highest when the steam flow rate is 0.1 kg·h⁻¹ . The increase of oxygen flow has a negative effect on the simulation re-sults. By summarizing the change rules of each index, the suitable operating conditions are ob-tained: The mixing ratio of raw material is 50:50, the gasification temperature is 750˚C, the steam flow rate is 0.1 kg·h⁻¹ , and the oxygen flow rate is 0.005 kg·h⁻¹ . Under these conditions, the simula-tion results are optimized. In syngas, H₂ is 54.43%, CO is 33.23%, CO₂ is 11.77%, CH₄ is 0.57%, low heating value of gas is 10.27 MJ·Nm⁻³ , dry gas yield is 1.26 Nm³ ·kg⁻¹ , gasification efficiency is 70.10%.