Parametric study of Aerosol Behaviour and Solvent Emission in a Post Combustion Carbon Capture

Parametric study of Aerosol Behaviour and Solvent Emission in a Post Combustion Carbon Capture

Harsha, Shreyas (TU Delft Mechanical, Maritime and Materials Engineering)

Vlugt, Thijs (mentor)

Delft University of Technology

Mechanical Engineering | Energy and Process Technology

2018-10-12

The amine-based post combustion carbon capture process is one of the most advanced and preferred technologies to reduce CO2 emissions from point sources like power plants. The emissions of amine from capture plants is one of the biggest challenges faced by this technology. These emissions typically occur by means of aerosol/mist formation. To develop effective countermeasures, it is crucial to understand the dynamic behavior of aerosols within the column, which is currently not well understood. This manuscript presents the results from a study aiming to understand the mechanism of aerosol growth and its behavior along the absorber column in terms of particles number concentration, particle size distribution, and amine emissions. For that, a series of experiments were performed in TNO's bench scale CO2 capture plant using 30 wt% monoethnolamine (MEA) as solvent. For a SO3 and CO2 concentrations of 5.25ppm and 12.5 vol.% in the flue gas, MEA emissions at the top exit of the column were recorded as 1051mg/Nm3 (with vapour emissions of 201mg/Nm3). In the absence of SO3 in the flue gas, inlet particle concentration was 2.71 x 107/cm3 and resulting MEA emissions reduced by 63.5% to 383mg/Nm3. From the bottom of the column until the point of maximum temperature, the MEA content in the vapour phase (<200mg/Nm3) was consistent with the volatility of the solvent. After this point it drastically increases to 1051 mg/Nm3. Both the number of particles and the total particle mass has lowered from the bottom to the top of the column. For the benchmark test, inlet and outlet total particle concentration were found to be 6.24x 107/cm3 and 2.3x 107/cm3 respectively, while total particle mass is 2.22mg/m3 at inlet and 1.32mg/m3 at outlet. Particles with a diameter below 0:006 μm contribute the most to total particle concentration both at the inlet (50%) and outlet (32%), while particles with diameter of 0:087 μm contributes the most to the total particle mass at inlet (47%) and outlet (55%). The measured total mass of particles was in the order of magnitude of 1mg/m3. This is much lower than the expected aerosol mass emissions, in the order of magnitude of 1 g/Nm3 based on FTIR emissions. Increasing the solvent temperature entering the absorber column to 50C caused an increase in total MEA emission (1345mg/Nm3). An increase in total MEA emissions (1793mg/Nm3) during an increase in solvent ow rate (26kg/h) was also observed due to the presence of excess unreacted free MEA present in the solvent. No particles larger than 0:147 μm were recorded, which might explain the low total mass recorded. The cause for this is still under investigation, but it suggests that the sampling procedure may induce systematic errors to the measurements. Nonetheless, the observations from this study have given further insight into the aerosol dynamics in the absorber column and corresponding emissions.

CO2-sequestration
Amine
Emission
Aerosols
MEA
CO2 capture
SO2

http://resolver.tudelft.nl/uuid:9d66f374-221c-4616-9c42-cb962309f54b

Student theses

master thesis

© 2018 Shreyas Harsha