膜吸收-再生循环技术捕集CO_2操作性能及其参数优化研究

采用N-甲基二乙醇胺(MDEA)+哌嗪(PZ)复合溶液作为捕集CO2吸收剂,研究了膜吸收-再生循环装置的操作性能,考察了气液流量、吸收剂浓度和再生电压等因素对捕集率和传质通量的影响,采用正交实验方法,优化操作条件,确定最佳操作方案。结果表明,气体流量对捕集率的影响明显大于液体流量的影响;气体流量增大对传质通量影响不明显;吸收剂浓度的增大使传质通量迅速增大,但大于一定值时通量不再增大;正交实验得出最佳操作条件为液体流量110 mL/min、气体流量0.65 L/min、吸收剂总浓度2.5 mol/L和再生电压210 V,捕集率大于95%,传质通量维持在5.86×10-4mol/(m2.s)。

Effects of operation parameters on performance of membrane contactor for CO2 capture and operation optimization

The operation performance of a membrane absorption-regeneration circulatory setup were investigated with a complex aqueous absorbent of N-methyldiethanolamine (MDEA) + piperazine (PZ) for CO₂ capture. Effects of gas and liquid flow rates, absorbent concentrations and regeneration voltages on CO₂ capture efficiency and mass transfer flux were studied. An optimal operation condition was determined by orthogonal optimization design. The results showed that, effects of gas flow rates on the capture efficiency was remarkably larger than that of liquid flow rates. The effects of the increase of the gas flow rates on the mass transfer flux was inconspicuous. The mass transfer fluxes rapidly increaseed with the increase of the absorbent concentrations. However, the flux no longer increased as the absorbent concentration reached a certain value. The optimum operation condition obtained through the orthogonal optimization design was the liquid flow rate in 110mL/min, the gas flowrate in 0.65L/min, absorbent concentration in 2.5mol/L and regeneration voltage in 210V. Here, the capture efficiency was higher than 95% and the mass transfer flux kept in 5.86×10^-4mol/(m²·s).