Laboratory Studies of Ammonia Emissions from the CO_2 Capture Process Using Aqueous Ammonia from the Solvay Process

摘要

The aqueous solutions of various amines are used as chemical absorbents in gas treating processes. It is considered that aqueous ammonia can be used as a promising solvent for CO2 capture. Apart from the many advantages of ammonia as a CO2 capture solvent, its major drawback is high volatility. As a consequence, a large amount of ammonia can be released into the atmosphere. In this paper we investigated the effects of process parameters on ammonia emissions from the absorber used for CO2 capture. Ammonia solution withdrawn from the ammonia recovery tower of the Solvay Process was used as solvent. During the research, the absorber pressure, liquid to gas flow ratio 9L/G) and concentration of ammonia have been varied. In addition, a novel simple method for quantitative analysis of absorbed CO2 in the ammonia solvent was described. We found that increasing the L/G ratio and ammonia concentration in the solvent resulted in a growth of ammonia emissions. The amount of released ammonia from the absorber was in the range 14-46 mg/dm(3). However, it is important to note that no emission reduction devices were applied. The test of CO2 capture using aqueous ammonia was satisfactory, with more than 90% of the inlet CO2 stream being removed.