Techno-economic and environmental analysis of decarbonization pathways for cement plants in Uzbekistan

Abstract

The cement industry is a major contributor to global carbon emissions and is characterized by high energy waste, necessitating urgent mitigation efforts. This study explores decarbonization pathways, including energy efficiency, clinker substitution, alternative fuels, and carbon capture, storage, and utilization technologies, for a 1 Mt/year cement plant in Uzbekistan. Waste heat recovery and CO2 capture technologies are identified as the most effective methods for this plant because of their high efficiency and sustainability potential. By using modeling tools such as Aspen Plus and Aspen Custom Modeler, various scenarios, including the cement plant baseline, amine-based CO2 absorption, membrane CO2 separation, and WHR units, are investigated to assess their techno-economic and environmental impacts. The study establishes design parameters for each unit and calculates both capital and operational costs. Compared with conventional amine absorption, the membrane separation process reduces the clinker cost, levelized cost of clinker, CO2 avoided cost, and CO2 capture cost by 31%, 34.3%, 72%, and 70%, respectively. The implementation of a waste heat recovery system with amine absorption and membrane separation further reduces annual indirect CO2 emissions by 17% and 35%, respectively, thereby lowering operating costs. Membrane separation systems prove to be more economical in terms of both capital and operational expenses, particularly when integrated with heat recovery systems, effectively offsetting the higher costs associated with amine-based systems.