沼气同时脱硫脱碳过程模拟

Simulation of Simultaneous Desulfurization and Decarbonization Process from Biogas

[目的]模拟沼气同时脱硫脱碳过程模型的建立。[方法]采用Aspen流程模拟软件建立了沼气同时脱硫脱碳的过程模型,以此为基础考察了吸收剂流量、浓度、温度和塔器的操作压力、塔板数等因素对脱除效率的影响。[结果]吸收剂MDEA的体积流量和浓度对沼气中H2S和CO2的脱除率有直接的影响;考虑到脱除成本,采用相对较低的MDEA浓度,最佳质量分数为10%左右;温度升高,吸收速率降低,低温更有利于吸收脱碳操作。增加吸收塔的操作压力能够提高H2S和CO2的脱除率,对H2S具有较高的选择性;对于含硫量偏高的沼气,增加操作压力,有助于提高处理效果。吸收塔板数对脱硫脱碳效果的影响不明显,一般采取11块板左右能够达到分离要求。[结论]该模拟结果对工业规模的吸收塔的设计和运行具有参考意义。

[Objective] To establish a simulation model of simultaneous desulfuriziation and decarbonization from biogas.[Method] Based on Aspen process simulation software,a simultaneous desulfurization and decarbonization model was established,based on which the impact of absorbent flow,concentration,temperature as well as the pressure and stage number of towers on the removal rate was studied.[Result] The absorbent volume and concentration of MDEA had direct effect on the removal of H2S and CO2 in biogas.Considering the cost of absorption process,low concentration of MDEA solution was selected,about 10%.The absorption rate decreased with the increasing temperature,low temperature was better for the absorption process.Increasing the operation pressure will raise the absorption rate of H2S and CO2,and show high selectivity for H2S.To deal with high content of sulfur biogas,the increasing of operation pressure help to improve the process effect.The number of stages showed insignificant impact on the absorption results,generally 11 plates were selected to meet the purification requirement.[Conclusion] The simulation results provide references for the design and operation of industrial scale absorber.