# Techno-economic assessment of hybrid post-combustion carbon capture systems in coal-fired power plants and steel plants

• Techno-ökonomische Analyse von kombinierten $CO_{2}$ Abscheideverfahren in Kohlekraftwerken und Stahlerzeugungsanlagen

Jülich : Forschungszentrum Jülich GmbH, Zentralbibliothek, Verlag (2020, 2021)
Book, Dissertation / PhD Thesis

In: Schriften des Forschungszentrums Jülich. Reihe Energie & Umwelt = Energy & environment 534
Page(s)/Article-Nr.: 1 Online-Ressource (IV, xx, 230 Seiten) : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2020

Abstract

Post-combustion carbon capture technology is seen as an indispensable option for global CO2 mitigation. Nevertheless, the benchmark post-combustion carbon capture technology, i.e. the MEA-based chemical absorption technology, has been reported to be rather energy-intensive. Meanwhile, the performance of the gas permeation membrane technology, one of the emerging alternative carbon capture technologies, has also been found to be restricted by the membrane properties, especially when it is designed to be applied in industrial-scale plants. As a result, the applications of the post-combustion carbon capture technology in the power and industrial sectors are faced with great resistance. On the other hand, the research of post-combustion carbon capture for industry is found to lag behind the power sector. The objective of this work is to advance the feasibility of post-combustion carbon capture technology as well as contribute to the study of carbon capture in the steelmaking industry. In order to do this, two types of hybrid membrane/MEA carbon capture systems (Hybrid D1 & D2) were designed in Aspen Plus®. In the Hybrid D1 system, a single-stage membrane is combined with an MEA system while a cascaded membrane system and an MEA system are combined in the Hybrid D2 system. For comparison, two widely studied standalone capture systems (cascaded membrane & MEA) were also modeled. The Polyactive® membrane was selected to be the investigated membrane material. These carbon capture systems were deployed in a reference coal-fired power plant and a reference iron & steel plant, respectively. A model of the power plant was simulated using EBSILON® Professional to represent the detailed operation. Pinch analysis was used to analyze the potential for waste heat integration of the capture systems into the water-steam cycle. In addition, the performances of the capture systems when the power plant is operated at part-load were investigated. As for the iron & steel plant, the energy use network and point sources of CO2 emissions inside the plant were analyzed so as to specify the boundary condition for carbon capture. A cost model based on the discounted cash flow approach was developed for economic analysis. In the power plant, it is revealed that the Hybrid D1 system is neither an energy-efficient nor a cost-effective design. The Hybrid D2 system, however, has shown to lead to both a lower efficiency penalty (9.7 %-pts) and a lower CO2 avoidance cost (48.8 €/tCO2) than the standalone cascaded membrane and MEA systems in the power plant. A basic principle for the design of a hybrid system is concluded according to the result. In the iron & steel plant, the Hybrid D2 system leads to the lowest CO2 avoidance cost (53.9 €/tCO2) but the differences in the avoidance costs of different capture systems are insignificant considering the uncertainty of the cost model. It is also found that the steam supply strategy has pronounced impacts on the cost competitiveness of a carbon capture system. In addition, it is disclosed that an overall lower CO2 avoidance cost can be achieved by deploying multiple types of capture systems to deal with different point sources of CO2 emissions as compared to deploying only one single type of capture system.