Process design and techno-economic risk assessment of a solid sorbent silica polyethyleneimine (Si-PEI) CCS process integrated into a cement plant

The paper examines the design and techno-economic risk assessment of a carbon capture and storage (CCS) process using silica-polyethyleneimine (Si-PEI) as a solid sorbent. This CCS process was integrated into a cement plant with an annual production of one million tonnes of clinker, representing the EU's average plant size. The study benchmarks the Si-PEI CCS process against the monoethanolamine (MEA) CCS process, assuming both systems capture 90 % of the plant's annual emissions. Aspen Plus models, validated through literature and experiments, simulated the CCS processes. A preliminary hazard analysis assessed technical risks, while economic risks were quantified using the Monte Carlo method, considering uncertainties in feedstock supply cost, cement selling price, solvent/sorbent cost, energy cost, and emission allowance price. The Si-PEI CCS unit emerged as the most favourable investment, being less expensive and technically safer than the MEA CCS unit due to its modular design and lower operating temperature. The economic advantage is attributed to the lower operation temperature (120 °C vs. 150 °C) and lower regeneration energy requirement (2.85 GJ/tonne CO2 vs. 4.25 GJ/tonne CO2). Maintaining a purge rate below 0.03 % is crucial for the solid sorbent's benefits over the MEA CCS process.