Simulation and Economic Optimization of Amine-based CO2 Capture using Excess Heat at a Cement Plant

Abstract

In order to remove CO2 from power or process industry, a well-known method is absorption in monoethanolamine (MEA) followed by desorption, and this technology has been in operation for decades. The major challenge is the high energy demand for CO2 desorption. In many industrial cases, a limited amount of cheap waste heat is available and this makes partial CO2 capture an interesting option. It is not obvious whether a high removal efficiency from a part of the exhaust or a low removal efficiency from the total exhaust is the optimum solution. In this work, simulations of traditional amine-based CO2 capture processes are performed with full-flow and part-flow of flue gas. The cost of CO2 capture is estimated using a detailed factor method and a Lang factor method. It is found that a full-flow alternative is the energy optimum while a part-flow alternative treating 80% of the exhaust gas is the cost optimum. This work shows that the calculated optimum is dependent both on the criteria used and on the selected method.