Using carbon to produce ethanol
In order to connect to a large market, the generation of ethanol suitable for drop-in fuel is another strategic development of HeidelbergCement to valorise CO2. On 11 December 2015, Joule Unlimited and HeidelbergCement announced their strategic cooperation. Joule has developed the technology to generate ethanol by means of modified bacteria that are exposed to sunlight and CO2. Cement plants that are located in sun-rich regions and have access to a considerable plot of (non-arable) land as well as (brackish) water are ideal locations to erect the bioreactor fields. Joule already operates a demo-plant in Hobbs New Mexico, though it is not connected to flue gas from cement production. This will be the next step to be realised jointly, followed by further scale up activities.
The technologies fitting best to the industry are those that use CO2 from flue gas to carbonate (waste) minerals into construction materials. These are initiatives that use exhaust gases to carbonate, for example olivine or other products that consist of a considerable amount of free lime, such as incineration ashes or oil shale ashes. Such technologies are different from classical capture technologies, as they bind the CO2 in a long living construction material that has an improved environmental footprint compared to classical binder materials.
Factors that determine the success of CO2 carbonation applications are on the one hand the costs and availability of (waste) minerals, and on the other the market size and value of the generated materials. The amount of CO2 uptake per t of end-product is another decisive factor for the attractiveness of the technology. HeidelbergCement has tested the technology in Norway and is currently exploring further applications.
For several decades, the cement industry has improved its environmental performance by converting from wet process kilns to dry kilns and further optimisation of dry kilns to nearly the optimum in energy efficiency. In parallel, more and more biomass fuels are used and low-clinker cement and concrete are produced.
The next jump in CO2 emissions abatement will come from capturing carbon and either storing it safely or turning it into a valuable feedstock for basic materials. Besides intensive collaboration on R&D and piloting within the cement industry, HeidelbergCement is also dedicated to exploring new opportunities. Those opportunities are not restricted to technology innovations but will also include innovative cooperation with other sectors in order to maximise and accelerate the implementation rate of viable CO2 mitigation projects.
This is part three of a three-part article written for World Cement’s May issue and abridged for the website. Subscribers can read the full May issue by signing in, and can also catch up on-the-go via our new app for Apple and Android. Non-subscribers can access a preview of the April 2016 issue here.
Read the article online at: https://www.worldcement.com/special-reports/02052016/theulen-heidelbergcement-capture-storage-utilisation-carbon-3/