The present work studied the simultaneous separation of H₂S and CO₂ from biogas by gas–liquid membrane contactor (GLMC) using single and mixed absorbents. The synthetic biogas contained 300 to 900 ppm of H₂S, 30% to 50% CO₂ and CH₄. To better understand the effects of different absorbents on simultaneous separation of H₂S and CO₂ from biogas, water, monoethanolamine (MEA, primary amine), potassium carbonate (K₂CO₃, inorganic salt), potassium hydroxide (KOH, inorganic salt), and potassium sarcosine (PS, organic salt) were applied as absorbent solutions. Poly(vinylidene fluoride) (PVDF) hollow fiber membrane was used in the membrane contactor modules. The simultaneous absorption performance of CO₂ and H₂S into single and mixed absorbents was investigated. In addition, the effects of liquid and gas velocities, absorbent concentration, acid gas content of the feed gas, and gas pressure on the absorption performance and the analysis of mass transfer coefficients were investigated. The results indicated that the highest H₂S absorption flux was obtained when KOH and K₂CO₃ were used as single absorbents, and the highest CO₂ flux was obtained using PS as the single absorbent. The use of promoted K₂CO₃ with PS solutions could simultaneously improve the absorption flux of H₂S and CO₂. Increasing the liquid flow rate and absorbent concentration led to an increase in the CO₂ absorption flux, while increasing the gas flow rate led to a significant increase in H₂S absorption; The change of liquid flow rate has little effect on H₂S absorption flux. A long-term stability test revealed that partial wetting of membrane could reduce the CO₂ absorption flux but has little effect on H₂S absorption flux. The detailed analysis of the mass transfer coefficients showed that liquid side resistance was negligible in comparison with membrane and gas side resistances for H₂S absorption. On the contrary, the mass transfer process of CO₂ was controlled by liquid mass transfer resistance.

中文翻译：

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气液膜接触器使用单一和混合吸收剂同时从沼气中分离H ₂ S和CO ₂

目前的工作研究了使用单吸收剂和混合吸收剂通过气液膜接触器（GLMC）同时从沼气中分离H ₂ S和CO _2的方法。合成沼气包含300至900 ppm的H ₂ S，30％至50％的CO ₂和CH ₄。为了更好地了解不同吸收剂对同时从沼气，水，单乙醇胺（MEA，伯胺），碳酸钾（K ₂ CO ₃）中分离H ₂ S和CO _2的影响，无机盐），氢氧化钾（KOH，无机盐）和肌氨酸钾（PS，有机盐）用作吸收剂溶液。膜接触器模块中使用了聚偏二氟乙烯（PVDF）中空纤维膜。研究了CO ₂和H ₂ S在单一吸收剂和混合吸收剂中的同时吸收性能。此外，还研究了液体和气体的速度，吸收剂的浓度，原料气中酸性气体的含量以及气体压力对吸收性能的影响以及传质系数的分析。结果表明，将KOH和K ₂ CO ₃用作单一吸收剂可获得最高的H ₂ S吸收通量，而CO最高。使用PS作为单一吸收剂获得了_2个助熔剂。PS溶液中促进K ₂ CO _3的使用可以同时提高H ₂ S和CO ₂的吸收通量。液体流速和吸收剂浓度的增加导致CO ₂吸收通量的增加，而气体流速的增加导致H ₂ S吸收的显着增加。液体流速的变化对H ₂ S吸收通量的影响很小。长期稳定性测试表明，膜的部分润湿可降低CO _2的吸收通量，但对H _2的影响很小S吸收通量。传质系数的详细分析表明，与吸收H ₂ S的膜侧和气体侧电阻相比，液体侧电阻可忽略不计。相反，CO ₂的传质过程是通过液体传质阻力来控制的。