Experimental studies on suppression of ammonia vaporization by additives



Aqueous ammonia (NH3) based CO2 capture process has been regarded as a promising technology to capture CO2 from many industrial sources including coal-fired power stations. However, this technology has been limited by the high volatility of ammonia and its relatively low reaction rate with carbon dioxide. This study selected nine kinds of chemicals and added them into ammonia solution as additives to investigate their potential to suppress ammonia vaporization. A wetted-wall column reactor was used to study the effect of additives on ammonia loss rate and overall gas mass transfer coefficient of CO2 at the absorption temperature of 15°C and solution of 3 M (mol/L) aqueous ammonia. Among all additives tested, Sulfolane (TMS) and Propylene carbonate (PC) showed the highest potential to suppress ammonia vaporization and enhance the reaction at the same time. The best scenario in this study was the addition of 0.3 M PC to 3 M aqueous ammonia under the CO2 loading of 0.4 which led to a reduction of ammonia loss by 38% and an increase of overall gas mass transfer coefficient by 10% compared to the case of no additive. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd