An Aspen Plus simulation of methanation of syngas from biomass gasification in a dual fluidized bed (DFB) was constructed and investigated in this work. The accuracy of the DFB gasification and methanation module was validated by comparing it with other experiments, resulting in a root mean square error (RMSE) of 2.98 % and 0.67 %, respectively. Based on this model, the effects of gasification temperature, steam-to-biomass ratio (S/B), methanation temperature and pressure on CH4 production were investigated throughout. The mass flow, energy flow, energy conversion efficiency and economic feasibility of the process were analyzed. The CH4 molar fraction of the synthetic natural gas (SNG) reaches more than 95 % under the optimal operating parameters of gasifier temperature of 800 °C, methanation temperature of 300 °C, S/B of 0.6 and methanation pressure of 3.0 MPa. The analysis shows that the system has an energy conversion efficiency of 60.59 % and a carbon conversion efficiency of 89.22 %. An economic analysis based on the discounted net present value (NPV) method shows that capital expenditures, annual operating costs and product costs are 2,262,815 USD, 471,557 USD/year and 101 USD/MWh, respectively. In conclusion, the proposed model offers valuable insights for designing, operating and commercially producing SNG via methanation of syngas from biomass gasification in a DFB.

中文翻译：

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双流化床中生物质气化合成气的甲烷化：Aspen plus 建模


本工作构建并研究了双流化床 (DFB) 中生物质气化合成气甲烷化的 Aspen Plus 模拟。通过与其他实验进行比较，验证了 DFB 气化和甲烷化模块的准确性，均方根误差 (RMSE) 分别为 2.98% 和 0.67%。基于该模型，研究了气化温度、蒸汽与生物质比(S/B)、甲烷化温度和压力对CH4产量的影响。分析了该工艺的质量流量、能量流量、能量转换效率和经济可行性。在气化炉温度800℃、甲烷化温度300℃、S/B为0.6、甲烷化压力3.0MPa的最佳操作参数下，合成天然气(SNG)的CH4摩尔分数达到95%以上。分析表明，该系统的能量转换效率为60.59%，碳转换效率为89.22%。基于贴现净现值（NPV）法的经济分析显示，资本支出、年运营成本和产品成本分别为2,262,815美元、471,557美元/年和101美元/MWh。总之，所提出的模型为通过 DFB 中生物质气化合成气的甲烷化来设计、操作和商业化生产 SNG 提供了宝贵的见解。