Simulation of low-carbon cement production system based on limestone hydrogenation for CaO production

DENG Yumeng; WU Jiawen; CAO Hongjie; LI Yingjie

doi:10.13226/j.issn.1006-6772.GPF25022601

Abstract：Cement production is a significant contributor to global CO2 emissions,and widely researched carbon capture,utilization and storage(CCUS)technologies face challenges related to high energy consumption.In traditional cement production,substantial CO2 emissions result from limestone decomposition.The introduction of green hydrogen into the calciner not only facilitates the reduction of limestone to CaO but also significantly lowers the calciner temperature and converts CO2 into high-value chemical feedstocks such as CO,enabling low-carbon and low-energy cement production.To evaluate the effects of replacing limestone decomposition with limestone hydrogenation in the calciner on the energy consumption,CO2 emissions,exergy efficiency and cost of the cement production system,an Aspen Plus simulation of a low-carbon cement production system based on limestone hydrogenation for CaO production was conducted and compared with a traditional system employing monoethanolamine(MEA)for CO2 capture.The results demonstrate that the limestone hydrogenation-based system significantly reduces the CO2 load on the subsequent MEA capture unit by converting raw material CO₂ into CO.Consequently,this system achieves reductions in energy consumption,CO2 emissions,and CO2 generation(including captured CO₂)by 19.42%,52.91%,and 37.55%,respectively,compared to the traditional system employing MEA for CO2 capture.Exergy analysis indicates that the primary exergy losses occur in the preheating and decomposition unit and the rotary kiln due to thermodynamically irreversible chemical reactions,with heat exergy losses arising from the large temperature differences between the hot and cold streams.Furthermore,the limestone hydrogenation-based system not only produces clinker but also generates syngas,thereby increasing the effective exergy output of the system.This results in an increase in exergy efficiency from 31.11%in the traditional system to 75.63%.Cost analysis indicates that green hydrogen raises the cost of the limestone hydrogenation-based system by 122.66%compared to the traditional system employing MEA for CO2 capture.However,the high profitability of the syngas offsets this cost,resulting in a net profit of 430.15 yuan/t clinker.The cement production system based on limestone hydrogenation for CaO production demonstrates significant advantages in energy consumption,CO2 emissions,exergy efficiency and cost,with promising prospects for industrial application.