Research On Ammonia Escape In CO₂Capture Process By Ammonia Method

As process of Greenhouse Effect deepens, the world is in continuous increasingpressure for reducing CO₂emission. Thus methods and strategies for CO₂controlling have been constantly improved all the time. Among these methods,CO₂capture by ammonia in post-combustion gases gained wide attention for itshigher efficiency, lower energy consumption and wider application range.However, ammonia escape will limit utilization and capability of absorbent, and also,cause the air pollution.In this work, experimental setup was designed and constructed based on bubblingreactor to investigate rules of ammonia escape in different conditions. Theammonia escape amount, CO₂absorption efficiency and CO₂load of absorbent weremeasured as ammonia concentration, temperature of absorbent, gas flow rate andgas component changed. Optimal conditions to reduce ammonia escape can begiven according to results of experiments and analysis for mass transfer theory.For further limit of ammonia escape, methods of using additives and scrubbingfacilities were brought out then checked by experiments. Results indicated that inlow ammonia concentration, low temperature, slow flow rate and high CO₂ratioconditions, amount of ammonia escape could drop by about9.5%³0.4%. Use ofethanol as additive could reduce ammonia escape amount by about10.5%¹7.8%.Use of scrubbing facilities for escaped ammonia capture could have an efficiency of95%⁹9.5%. Estimate of ammonia escape amount could be limited within10ppmunder optimal condition in conjunction with additives and scrubbing facilities.High light of this work is that it’s the first systematical investigation for ammoniaescape based on CO₂capture background. Chemical titration was adopted asmethod for ammonia measuring in liquid while FTIR was used for componentmeasuring in gas phase, the results of which were exact and direct. Additives andscrubbing facilities in optimized condition could significantly reduce the escapeamount which provides reference for further study on ammonia escape.