10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Aerosol Formation and Growth in Amine-based CO2 Scrubber: Experiments and Numerical Simulation
DAVID I. A. DHANRAJ, Zhichao Li, Pratim Biswas, Washington University in St. Louis
Abstract Number: 412 Working Group: Aerosol Modeling
Abstract The concerns owing to global warming and climate change have initiated significant efforts to reduce the concentration of atmospheric CO21. Post-combustion CO2 capture using amine solvents is currently the key economical retrofit process for large power plants2. Amine loss is a primary challenge for amine-based CO2 scrubbing technology considering its environmental and economic impacts. The presence of fine particles in flue gas is regarded as the major contributor of aerosolized amine emissions. Experiments using a lab-scale structured packing spray column were conducted to investigate the effects of inlet particle size distribution, gas flow rate and amine flow rate on the particle size distribution at the outlet. The results indicate that the total number concentration of particles with diameter in the range from 10 nm to 450 nm increased significantly after passing the scrubber. It was also seen that a small fraction of the particles larger than 1 µm was trapped in the scrubber. From these experiments, it can be inferred that increasing the number concentration of submicrometer particles and liquid flow rate could further increase the aerosol emission. Moreover, it is known that supersaturated amine in the vapor phase is the major contributor of aerosolized amine emissions. Amine vapor condenses on the fine particles and further grow by coagulation. In order to understand the processes that govern the formation and growth of particles, a discrete sectional model was used to simulate the relevant physical phenomena under industrially relevant operating conditions. Further experiments are performed to investigate the effects of amine and CO2 concentration, operating temperature and pressure on aerosolization. These experiments and simulations provide insights for optimized design and operation strategy in order to minimize amine losses in a full-scale amine scrubber.
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