Stochastic Techno-Economic and Environmental Optimization of Carbon Capture and Utilization (CCU) from Cement Plant for Green Brick Production

While carbon capture and utilization (CCU) technology often face economic challenges, CCU via carbon mineralization with solid waste offers a cost-effective solution. In this work, the feasibility of a proposed CCU process that utilizes captured CO2 from the accelerated weathering of limestone (AWL) process to mineralize cement kiln dust (CKD) to produce a green brick termed CKD-bicarbonate lime brick (CKD-BLB) was evaluated with techno-economic analysis (TEA). The main variable that affects the techno-economic feasibility of the proposed CCU process is the absorber size, as it dictates the amount of captured CO2 and producible CKD-BLB. This variable also indirectly impacts the environmental aspect, as different absorber sizes contribute to varying degrees of CO2 avoidable. Thus, this work conducts a multi-objective stochastic optimization to determine the optimal absorber size with consideration of profitability and CO2 avoidance. It was found that the optimal absorber size of 67.93 m3 achieved a maximum NPV of $ 3,165.38 million with a desirable CO2 avoidance of 21,337.41 $${\text{M}\text{T}}_{{\text{C}\text{O}}_{2}}$$ . Although increasing the absorber size to 93.96 m3 would increase the process’s avoidable CO2 by 2.87%, the 3.22% drop in its NPV result is a less favorable tradeoff between the two aspects. A sensitive analysis was also conducted, and the results indicate that among CKD-BLB price, electricity cost and water cost, the CKD-BLB price is the most sensitive parameter affecting the NPV of the proposed process. A ± 50% variation in CKD-BLB price leads to more than a 100% shift in NPV, while at a ± 50% variation in electricity and water costs results in less than a 30% change. Overall, the insights generated in this work enable strategic planning for decisions making.