液相共存成分对双极膜电解吸氨法脱碳富液的影响

Effect of liquid coexistent components on ammonia decarbonization solution desorption using bipolar membrane electrodialysis

考察了烟气中SO2、NOx和CO2与NH3·H2O的反应机理以及双极膜电解吸的机理,对本文自制实验系统的操作工况进行了进一步的调整,探究了氨法脱碳吸收富液双极膜电解吸的一般规律,研究了模拟解吸液解吸过程中主要液相共存成分,如(NH4)2SO3、(NH4)2SO4、NH4NO3、Na Cl和NH4Cl对CO2双极膜电解吸的影响。研究表明,液相共存成分种类、质量分数、pH、表面张力等对CO2的双极膜电解吸均能产生一定影响。少量Na Cl、NH4Cl和(NH4)2SO4成分的共存对吸收富液的电解吸是有利的,且对电解吸的影响程度为Na Cl>NH4Cl>(NH4)2SO4;吸收富液中应该极力避免(NH4)2SO3成分的存在;NH4NO3成分的共存对脱碳富液电解吸的影响不大。因此,在碳捕集前应对烟气中的杂质成分进行脱除,减少其对解吸液理化特性以及双极膜电解吸的影响。

The reaction mechanisms of SO2, NOx and CO2 in flue gas with ammonia solution and desorption mechanism of bipolar membrane electrodialysis were described. Furthermore, the operation conditions of self-dissembled experimental system were adjusted and the desorption general rules of ammonia decarbonization solution using bipolar membrane electrodialysis were explored. There were many major liquid coexisting components in rich solution after ammonia decarbonization, such as（NH4）2SO3,（NH4）2SO4, NH4NO3, Na Cl and NH4 Cl. Impacts of these major liquid coexisting components on bipolar membrane electrodialysis were studied. Researches have shown that types of liquid coexisting components, mass fraction, pH values and surface tension all can have an impact on the bipolar membrane electrodialysis. Small amounts of Na Cl, NH4 Cl and（NH4）2SO4were good to electrodialysis of absorbing solution, and the effecting degree on electricity desorption was Na ClNH4Cl（NH4）2SO4. Existence of（NH4）2SO3 should be avoided in absorption rich solution. Coexistence of NH4NO3 had no significant impact on the electrodialysis of rich solution after ammonia decarbonization.