Demonstrating the effect of solvent aging on the volatile and aerosol-based emissions of the AMP/PZ-based solvent CESAR1 after 1,000 h and 30,000 h operation

A prerequisite for establishing reasonable guidelines for environmental, technical, and economically effective control of the emissions from amine-based capture plants is real-life testing of individual emission mitigation technologies in an industrial environment for different technical use cases and solvents. The operational data is also essential for validating and optimizing process models that predict volatile and aerosol-based emissions. The effect of solvent aging on the emissions of the capture plant is complex and affected by contrary trends. It is expected that emissions of volatile degradation products should increase with increasing degradation of the solvent and that the vapor pressure of the volatile solvent amines may be unaffected or even decrease by solvent aging due to increasing concentration of ionic non-volatile components in the solvent and water wash liquid based on salting out effects. To analyse the effect of solvent aging on volatile and aerosol-based emissions, two testing campaigns have been executed at the capture pilot plant in Niederaussem, Germany, using CESAR1 solvent, an aqueous solution of 3.0 M 2-amino-2-methylpropan-1-ol (AMP) and 1.5 M piperazine (PZ). The comparison of the levels of AMP, PZ, and NH3 emissions after 30,000 h operation without exchange of the solvent inventory and with a relatively fresh solvent inventory after 1,000 h operation shows a significant difference in the emission behavior of AMP and PZ when just a water wash is used to control the emissions of the capture plant. The AMP emissions of the fresh solvent are by a factor of two higher than for the aged solvent, while the emissions of PZ show no significant change with solvent aging or accumulation of contaminants. Two possible explanations for this unexpected strong effect are discussed in this work. However, there are effective emission mitigation technologies that can control emissions irrespective of solvent aging.