Investigation of aerosol based emission of MEA due to sulphuric acid aerosol and soot in a post combustion CO2 capture process

The prevention of emissions of amine species is of high importance for the overall sustainability and performance of Post Combustion CO2 Capture facilities. There is a clear understanding of amine emissions based on volatility in the treated flue gas. Emission via aerosols from Post Combustion CO2 Capture facilities has only been pointed out recently. Thus, there is little knowledge about emission via aerosols in contrast to emission based on volatility. It has been found that flue gas quality plays an important role for emissions caused by aerosols formation. In this work, we study the experimental assessment of the impact of flue gas quality on the level of monoethanolamine (MEA) emission via aerosols. In a dedicated test rig, effects of the flue gas components such as sulphuric acid aerosols and extremely fine particles like soot has been studied. An aerosol generator capable of producing controlled amounts of soot and dosing sulphuric acid aerosol to a mobile CO2 capture mini-plant was used as a test equipment for this study. Soot particle number concentration were in the range of 104-106 per cm3. The particle number concentration for different amount of H2SO4 aerosols were in the order of 108 per cm3. Amine emissions up to 4.3ppmv (12mg/Nm3 for MEA) is considered to be as an upper limit for the design of a Post Combustion CO2 Capture plant. MEA emissions in the presence of soot particles were in the range of 100-200mg/Nm3 which is 2-4 times higher than baseline vapour based emissions of about 45mg/Nm3. The expected particle size of H2SO4 aerosols is well below 100nm, while the corresponding mass concentration range is between 1 and 5mg/m3. The MEA emissions observed due to H2SO4 aerosols were in the range of 600-1100mg/Nm3. Moreover, parametric tests have shown that besides flue gas quality, the absorber temperature profile and the presence of CO2 in the flue gas are pre-requisite for aerosol emissions. It is evident that the observed level of emissions in this study are unacceptable. Therefore, it is imperative that fundamental know-how about aerosol formation and reduction is generated in order to design appropriate counter measures. © 2013 Elsevier Ltd