Aqua ammonia is thought to be a feasible new absorbent for CO2 capture in recent years because of its high CO2 removal efficiency

high loading capacity and the possibility of removing NOx and SOx simultaneously.The heat of reaction for aqua ammonia regeneration was considered as low as 26.88 kJ·（mol CO2）-1 before

which was much lower than 85 kJ·（mol CO2）-1 for MEA regeneration.Data from literature were collected and compared

and their reliability was analyzed in this work.It was found that both our theoretical estimation and experimental data disagreed with those from earlier economic analyses for aqua ammonia capture system.The experimental data in this paper also confirmed that the heat of absorption was about 60—70 kJ·（mol CO2）-1 and was seemingly independent of CO2 loading at a low temperature (35℃).The heat of absorption at a high temperature (80℃) was about 60 kJ·（mol CO2）-1 at the beginning

rose to a maximum of around 120 kJ·（mol CO2）-1 with increasing loading

and then decreased to 80 kJ·（mol CO2）-1 after a certain high loading value was reached.It was impossible to get heat of absorption as low as 26.88 kJ·（mol CO2）-1 according to the experimental data of CO2 in ammonium carbonate solutions.Therefore，aqua ammonia had advantage in energy saving

however the advantage of aqua ammonia over other amine solutions was not as obvious as expected.