The Project

Why C4U?

The iron and steel industry represents the largest energy-consuming manufacturing sector in the world, with average specific emissions being 1.83 tonnes of CO2 per tonne of steel and global crude steel production reaching 1.8 Gt for the year 2018, up by 4.6% compared to 2017. This enormous CO2 footprint of steel mills, which accounts for up to 8% of anthropogenic CO2 emissions must be substantially reduced.

Given the urgency of emission reductions, the very different characteristics of the CO2 containing streams emanating from steel plants and the huge quantities of CO2 involved, a portfolio of promising CO2 capture technologies must be developed and practically tested to high TRL to identify the optimal integration solutions that deliver the minimum cost and energy consumption.

Haroun MahgereftehThe critically important 2030 net zero emission target cannot be met without curtailing CO2 emissions from the steel making industries. A multidisciplinary approach spanning technology development, safety, environmental, societal, policy and business aspects is required to tackle this huge challenge. The C4U project is aimed at achieving this.” – Prof. Haroun Mahgerefteh, UCL
The C4U Project Coordinator


C4U CO2 Capture Technology

C4U aims to advance 2 emerging carbon capture technologies, known as DISPLACE and CASOH, which have the potential to tackle up to 94% of the CO2 sources in a steel mill.


DISPLACE – high-temperature sorption-displacement process for CO2 recovery

CASOH – Calcium Assisted Steel mill Off-gas Hydrogen production

Both DISPLACE and CASOH technologies involve high temperatures gas-solid separation processes that reduce the exergy penalty associated with CO2 capture. This is due to their ability to:

  1. recover heat at very high temperatures that can be used for energy-demanding processes in the steel plant (i.e. reheating furnaces and CO2-free power generation), and
  2. co-produce H2/N2 fuel gases that can lead to the decarbonization of energy-consuming processes in the steel mill or the manufacture of high-value products.

These C4U capture technologies will be optimised for a wide range of operating conditions typical of steel mills, leading to a significant improvement in Key Performance Indicators (KPIs), such as the capture rate and associated energy and cost requirements.

The C4U capture functional materials are not on the Critical Raw Materials list of the EU.

The experimental testing at TRL7, combined with the modelling work at capture plant, steel mill and industrial cluster levels, will provide the basis for C4U capture technology scale-up and hence precise and reliable cost estimates at TRL9, whilst meeting the CO2 quality requirements for pipeline transportation, utilisation and storage.

Integration into CCUS Clusters

The planned North Sea Port industrial CCUS cluster. Figure courtesy of North Sea Port, Gent, Belgium.

Regarding the connection of the CO2 streams to the pipeline transport networks for ultimate geological storage and/or utilisation, many relevant issues need to be considered to identify techno-economic optimums. Work based on CO2QUEST and CO2PipeHaz projects has shown that many of the impurities in the CO2 stream even if present in small proportions have unique and likely significant impact on the CO2 compression work, cost of capture and ultimately the economic and safe operation of both the transportation pipeline and the storage site. These issues can be dealt with by further purification of the steelworks off-gases and/or captured CO2 but the inevitable increase in cost may become prohibitive. As such, a whole-system approach is required balancing the different requirements of capture, pipeline transportation and storage, as well as society.

An important challenge for the development of CCUS clusters is to demonstrate and commercialise the entire value chain and to establish a framework for the long-term business case, requiring governmental and public support.

The C4U project will capitalise on the diversity of stakeholder knowledge and the technology base to optimise the performance of next generation capture technologies, integrated with their industrial emissions sources and operating as part of the North Sea Port CCUS industrial cluster.

C4U is the first project to consider technology development alongside societal, business and policy considerations for a real industrial cluster by taking into account all the major relevant factors and actors. We balance the technical demonstration with integrated and solution-focused societal readiness research, distinguishing between public and private sector stakeholders.