Partial CO2 capture to facilitate cost-efficient deployment of carbon capture and storage in process industries - Deliberations on process design, heat integration, and carbon allocation

Abstract: Climate change requires that all energy-related sectors reduce drastically their greenhouse gas (GHG) emissions, at a global rate of 1–2 GtCO2 per year, starting now. Process industries, such as the iron and steel, cement, petrochemical, and oil-refining industries, are inherently carbon-intensive, and carbon capture and storage (CCS) is one of the few options available to achieve the required deep reductions in carbon dioxide (CO2) emissions. Despite being technologically mature, CCS has so far not been implemented at the required rates. This is due inter alia to the low value created by CCS for process industries, which is attributed to uncertainties related to carbon pricing and the considerable investments required for CO2 capture installations. This thesis explores the concept of partial carbon capture as an opportunity for the process industry, as part of its transition, to operate in a net-zero emissions framework by the middle of this century. Partial capture is governed by market and site conditions, and aims to capture a designated share of the CO2 emissions from an industrial site, thereby lowering the absolute and specific costs (in€/tCO2) for CO2 capture, as compared to a conventional full-capture system. The thesis elaborates the relevant technical, economic, and policy-related aspects related to facilitating the near-term implementation of carbon capture at industrial sites. These aspects include: 1) the energy- and cost-effective design of solvent-based processes for partial capture, which can lead to capture cost savings of up to 10% for gases with a high CO2 content (>17 vol.%wet); 2) the efficient use of residual heat and existing capacities on-site to power partial capture, which in case studies of an oil refinery and an integrated steel mill, are shown to confer cost savings along the entire CCS chain of 17%–24%; 3) the incorporation of site realities, such as temporal variations in heat availability, into techno-economic assessments; 4) the adaption of policies that address the allocation of carbon emissions reductions to low-carbon products, so that investments in mitigation technologies are incentivized with respect to the ambition level; and 5), the recognition of the rather narrow window of opportunity for partial capture with regard to the lifetime of the existing infrastructure, alternative production and (co-)mitigation technologies, as well as the regional energy and CO2 transport and storage systems. As the title image indicates, the share of carbon extracted from the earth that is sequestered needs to reach 100% by mid-century, in order to limit global warming in line with the targets of the Paris Agreement (i.e., 1.5°C or well below 2°C). Thus, partial capture is only a short-term solution for kick-starting CCS, and it will eventually have to lead to full capture, alternatively full mitigation (e.g., via carbon-free production), or be combined with renewable feedstocks if used in the longer term. Therefore, it is timely for the process industry to apply partial capture and, thereby, ramp up widespread adoption of CCS, so to build up the infrastructure for direct removal of carbon from the atmosphere, which will be required on the gigatonne scale in the second half of the 21st Century.