Effect of number concentration of soot and H2SO4 on aerosol based emissions from a post combustion capture plant

It is known that the use of volatile solvents for a post combustion capture process can lead to emission of the solvent due to their high vapour pressure. More recently, the issue of emission due to the formation of aerosols has been observed at different pilot plants. Therefore, it is of high importance to understand the mechanism of the formation process of aerosols. The main hypothesis regarding the formation of these aerosols is related towards the presence of nuclei in the flue gas. These nuclei can be sulphuric acid aerosol droplets, fine particles (e.g. fly ash, soot), etc. which are present especially, in flue gases from coal fired power plants. This article describes the experimental results of the effect of soot and H2SO4 aerosol number concentration on solvent emissions from a typical absorber-desorber setup. The solvent used in this study is 30 wt. % MEA. This work was carried out as a collaboration between TNO, KIT, E.ON and Laborelec/GDF SUEZ. To study the effect of the presence of nuclei in flue gases, TNO’s mobile carbon capture pilot plant, as shown in Figure 1, was used. This system is a conventional absorption-desorption system with a capacity of 4 m3/h of flue gas. KIT’s pilot plant, as shown in Figure 2, produces 180 Nm3/h of flue gas from domestic natural gas combustion. Varying amounts of SO3 can be added to this flue gas to generate the desired amount of H2SO4 aerosol droplets in the quench column by homogeneous nucleation. Additional CO2 can also be added to simulate power plant flue gas conditions.The number concentration was measured by a Condensation Particle Counter (CPC). A Gasmet FTIR from Laborelec was used to follow the emission of MEA and other inorganic components. Laborelec also performed tests to characterize the particulates concentration and size distribution with an ELPI+ system along with manual SO3 measurements.