07/26/2023
Source: Energy & Management Powernews
The building materials producer Holcim is investigating CO2 capture from flue gas produced during cement production at its site in Höver.
Built into wind turbines, houses and bridges, cement is widely used as the main component of concrete and mortar. As part of the research project "ErfMemDekZem", the building materials producer Holcim, headquartered in Zug (Switzerland), is working on separating the climate-damaging greenhouse gases from the resulting flue gas and processing them for further use. The project name stands for "Industrial research into membrane-based CO2 capture for the decarbonization of cement plants."
The CO2 footprint of the cement industry
The production of one ton of cement involves the emission of around 600 kilograms of CO2 due to the raw material. Annually, around 20 million tons of the greenhouse gas are thus released into the atmosphere in Germany, according to Holcim. According to the building materials producer, this amount corresponds to about 10 percent of Germany's total industrial emissions.
Cement clinker burning in particular produces flue gases containing CO2. Currently, about two-thirds of the emission release from raw materials is unavoidable in cement production. Lower greenhouse gas emissions are only possible by capturing the carbon dioxide released during the process. For this reason, industrial research and demonstration of CO2 capture technologies (carbon capture) plays a central role.
A membrane-based process is to be used, which Holcim intends to test for the first time in the cement sector. The Cottbus-based Competence Center for Climate Protection in Energy-intensive Industries (KEI) is supporting the project through the "Decarbonization in Industry" funding program. It supports projects in energy-intensive industries that reduce process-related and hardly or not at all avoidable greenhouse gas emissions as far as possible and permanently. The German Federal Ministry of Economics and Technology is supporting Holcim's project with around 1.3 million euros until the end of 2024.
The company puts the total investment for research and trial operation of the CO2 capture plant, which Holcim is planning at its Höver site southeast of Hanover, at 2.6 million euros. In Höver, the so-called "PolyActive" membrane technology is to be used to separate CO2 from the flue gas of the existing cement plant. According to Holcim, the membrane allows the CO2 flowing through it to pass more easily than other gases. The CO2 can thus be better separated from the flue gas mixture.
From 16 to 530 square meters
The carbon capture technology has already been successfully tested in the laboratory and in pilot studies at two coal-fired power plants, Holcim said. Those studies worked with smaller membrane areas of up to 16 square meters to capture CO2 from biogas and flue gases from coal-fired units. A membrane module with an area of up to 530 square meters is now being installed in the pilot project at the Höver cement plant.
The particular challenge in complex industrial production, according to Holcim, is to test key parameters - such as pressure, temperature and energy consumption - for the first time for a climate-friendly process under real conditions. The Mebran process is being co-developed by the two partners "Helmholtz-Zentrum hereon GmbH" and Cool Planet Technologies Ltd, it adds.
Holcim says it envisages several phases of the project, which is now underway. About 5,750 metric tons of CO2 are to be captured in the first phase this year. The final expansion stage is expected to be able to capture 90 percent of CO2 emissions from the flue gas. High-purity CO2 in liquid and gaseous form is to be available for storage or further use at the end. Holcim intends to transfer the knowledge gained to its 150 sites worldwide.
Author: Davina Spohn
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