Towards a carbon negative large-scale clinker plant through first-ever demonstration of a groundbreaking flue gas recirculation & concentration-based concept paired with a full CCS solution

Introduction

The GO4ZERO project aims to put into operation an innovative pollutant-free and carbon-negative clinker kiln in the Holcim Obourg plant located in Wallonia, Belgium. The project will couple an oxy-combustion process with a large-scale carbon capture and sequestration system (CCS). The oxyfuel clinker kiln design significantly concentrates CO2 in its flue gases, and CO2 processing technologies will make the project excel in carbon capture and purification.

CO2 Processing and Transportation

The processed CO2 will be transported by pipeline to the Antwerp@C CO2 Export Hub, where it will be liquefied and loaded onto CO2 ships for permanent and safe offshore storage beneath the North Sea. The project is expected to have a 103% avoidance in relative greenhouse gas (GHG) emissions when compared to the reference scenario without implementing Carbon Capture and Sequestration.

Innovative Technologies

The project will combine several innovative technologies to produce a carbon-negative clinker, ultimately supporting the construction sector in improving its sustainability. Key aspects include:

1. The CO2 intensity per tonne of clinker will be below the European benchmark value prior to carbon capture.
2. Utilization of low heat consumption, optimized combustion, and gas recirculation conditions.
3. Intensive use of alternative high-biomass content fuels and decarbonized raw materials.

The cement portfolio will be further developed to reduce the embedded clinker factor (the amount of clinker in cement) and to push the use of new mineral components in substitution to clinker and slag.

Energy Input and Emissions

The plant will also contribute a very low level of indirect carbon emissions from energy input. This will be achieved through a combination of:

• Sourcing energy from a locally developed 30 megawatt (MW) floating photovoltaic farm.
• Secured electricity through Power Purchase Agreements (PPAs).
• Installation of a Waste Heat Recovery system, yearly producing 50 gigawatt hours (GWh) of energy.

Additionally, to reach the inlet gas specifications of the cryogenic purification unit (CPU), the design of the oxyfuel kiln is combined with cleaning technologies for flue gases. This combination will be the first of its kind, including:

• A wet scrubber.
• A thermal oxidizer.
• Selective non-catalytic reduction (SNCR).

A cooling and condensing unit will extract water from the kiln gases and send it to a condensate treatment plant to comply with strict wastewater disposal conditions.

Production and Environmental Impact

The project is planning to produce annually more than 2.3 million tonnes (Mt) of carbon-neutral cementitious materials, mainly cement but also clinker, pioneering work on the path to a sustainable construction sector. It will also avoid more than 10 million tonnes CO2 equivalent of absolute GHG emissions over the first ten years of operation.

The project will contribute to the European objectives to reach climate neutrality by 2050, and in particular to the Net-Zero Industry Act to reach 50 Mt per year of CO2 storage capacity in 2030.

Dissemination and Job Creation

The dissemination of the project results, developed knowledge, and lessons learned will directly benefit all stakeholders throughout the project lifecycle, accelerating the roll-out of the oxyfuel process combined with an efficient carbon processing unit. The project is expected to create 18 direct jobs for the oxyfuel kiln, auxiliaries, and the CPU, along with 54 indirect jobs.