为了提高沼气液化的CO₂脱除指标，简化脱碳工艺，采用带压液化技术设计了一种混合冷剂沼气带压液化流程：将预处理后的沼气二级膜分离，得到高纯度CH₄流和富CO₂流，再经带压液化和精馏，得到液态CH₄和食品级液态CO₂。HYSYS流程模拟表明，对于流量为1 000 kg/h、组分为60% CH₄+40% CO₂的模拟沼气，该流程可实现沼气液化率84.24%、CH₄回收率83.62%、CO₂回收率85.17%、液态CH₄产出率51.06%、液态CO₂产出率33.18%、产品总销售额7 797元/h。在此基础上，建立了HYSYS&Matlab混合仿真平台，以产品比功耗为目标函数，采用序列二次规划（SQP）算法，对流程进行了优化，优化后的比功耗降低了26.8%。最后，通过调整沼气组分（CH₄ 57%~62%）和流量（920~1 060 kg/h），分析了优化工况的适应性。

To improve CO₂ removal index of biogas liquefaction and simplify its decarbonization process,a biogas pressurized liquefaction process with mixed refrigerant is designed.After the pretreated biogas is separated by a two-stage membrane,a high-purity CH₄ stream and a CO₂-rich stream are obtained.Liquid CH₄ and food-grade liquid CO₂ are obtained through liquefication and distillation under pressure.HYSYS simulation shows that this process can realize a biogas liquefaction rate of 84.24%,a CH₄ recovery of 83.62%,a CO₂ recovery of 85.17%,a liquid CH₄ output rate of 51.06%,and a liquid CO₂ output rate of 33.18% when the simulated biogas has a flow of 1 000 kg·h^-1 and a composition of 60% CH₄+40% CO₂.Based on this,HYSYS & Matlab,a co-simulation platform,is constructed.Taking the product specific power consumption as the objective function,the process is optimized by the sequential quadratic programming (SQP) algorithm.Specific power consumption reduces by 25.83% after optimization.Finally,the adaptability of the optimized conditions is analyzed by adjusting the biogas composition (CH₄ content between 57% and 62%) and flow (920-1 060 kg·h^-1).

常明亮(1994-),男,硕士生