Process Modeling of an Advanced NH₃ Abatement and Recycling Technology in the Ammonia-Based CO₂ Capture Process

Abstract

An advanced NH3 abatement and recycling process that makes great use of the waste heat in flue gas was proposed to solve the problems of ammonia slip, NH3 makeup, and flue gas cooling in the ammonia-based CO2 capture process. The rigorous rate-based model, RateFrac in Aspen Plus, was thermodynamically and kinetically validated by experimental data from open literature and CSIRO pilot trials at Munmorah Power Station, Australia, respectively. After a thorough sensitivity analysis and process improvement, the NH3 recycling efficiency reached as high as 99.87%, and the NH3 exhaust concentration was only 15.4 ppmv. Most importantly, the energy consumption of the NH3 abatement and recycling system was only 59.34 kJ/kg CO2 of electricity. The evaluation of mass balance and temperature steady shows that this NH3 recovery process was technically effective and feasible. This process therefore is a promising prospect toward industrial application.

Technical and Energy Performance of an Advanced, Aqueous Ammonia-Based CO2 Capture Technology for a 500 MW Coal-Fired Power Station

“…Recently, the focus of modeling work has been shifted to the development of the rigorous, rate-based models for CO 2 absorption and desorption using aqueous ammonia, which is considered to more realistically and accurately evaluate the NH 3 -based CO 2 capture process, guide the process optimization, and scale up. Qi et al, 12 Li et al, 16 and Yu et al 17 have developed rate-based models for CO 2 absorption and regeneration and validated the models using pilot-plant data. These models help obtain a detailed understanding of the interrelationship between the operating conditions and the CO 2 capture performance.…”

Experimental study on CO2 capture by chilled ammonia process

“…Likewise, a simulation study of ammonia-based CO 2 capture was presented recently by Li et al [16], in which they suggest utilizing flue gas temperature to mitigate the ammonia slip. The CO 2 capture using the CAP is not yet a commercialized technology.…”

CO2 absorption characteristics in a random packed column with various geometric structures and working conditions

“…found that the wall flow is more likely to occur in the random packed column. Li et al . and Asif and Kim proposed a rate‐based model for the NH 3 ‐CO 2 ‐SO 2 ‐H 2 O system to strongly adapt to different scenarios such as high SO 2 level in flue gas and high NH 3 level from the CO 2 absorber, which requires a less energy input and a significantly reduced cost of CO 2 and SO 2 capture.…”

“…Using X-ray tomography, Schmidt et al 10 found that the wall flow is more likely to occur in the random packed column. Li et al 11,12 and Asif and Kim 13 proposed a rate-based model for the NH 3 -CO 2 -SO 2 -H 2 O system to strongly adapt to different scenarios such as high SO 2 level in flue gas and high NH 3 level from the CO 2 absorber, which requires a less energy input and a significantly reduced cost of CO 2 and SO 2 capture. Chu et al 14 investigated the CO 2 absorption by ammonia solution in a structured packed column by using an improved computational model based on the representative elementary volume (REV) method and pseudo-single-liquid model, finding that the ammonia solution flow rate and concentration play important roles in the mass transfer process.…”