At the beginning of October, 140 representatives from the arena of CCU (carbon capture & utilisation) met for three days in Essen at Europe’s largest conference on “CO2 as chemical feedstock – a challenge for sustainable chemistry”. According to the Nova-Institute, the possibility of re-using harmful waste carbon dioxide as a feedstock in the chemical industries, as well as an ingredient in plastic manufacture is a lot closer than most of us realise.
Carbon dioxide does not necessarily have to be reduced for use in chemical building blocks, but can instead be directly incorporated into chemical structures, partly even into exothermic processes. Professor Matthias Beller of the Leibnitz Institute for Catalysis in Rostock presented to the group various methods of direct CO2 incorporation that have been developed in recent years. One of these processes is already operational, due to be commercialised in less than two years. Dr Christoph Gürtler from Bayer MaterialScience (BMS) in Leverkusen (Germany) presented the current progress of his “dream production” project. Starting in 2015, a commercial facility is to be built in North Rhine-Westphalia (Germany) that is scheduled to produce several thousand tonnes of foam material from CO2-based polyol. For the very first time, there was a presentation of a life-cycle assessment of the “dream production”, which had been jointly carried out by RWTH Aachen (Germany) and BMS. Nicklas von der Assen of RWTH Aachen was able to show at the conference that CO2-based polyol production performs better in the life-cycle assessment than fossil-based production. The assessment included the CO2-emitting power station as well as all its power production.
Dr Xiaoqing Zang and his CSIRO agency (Australia) are working with composites made from CO2-based polypropylene carbonate (PPC), which is already produced in the USA, China and South Korea. Zang showed various composites containing wood and natural fibre with PPC compared with PLA and petrochemical polymers. PPC is well suited for wood-plastic composites. It binds well with cellulose and improves its impact resistance. Mixtures of biodegradable PPCs (30-40%) and biopolymers are also of interest for grocery bags, for example. Zang expects mass production to bring the price down to $1 per kg.
Finally, Dr Klaas Hellingwerf from the University of Amsterdam presented genetically tailor-made bacteria, algae and enzymes that can produce lactic acid directly from CO2 for PLA production. It seems that foams, composites and PLA all have potential to draw on CO2 as a resource.
But experts are asking which is the most attractive source of CO2? At present this would appear mainly to be carbon dioxide emissions from fossil-burning power station and industries such as the steel industry, as well as bioethanol plants. These produce large volumes of CO2 that would have to be cleaned so as not to destroy the catalyser or the electrolysis unit. Direct air capture would be the ideal way, as one would not have to resort to large-scale fossil-powered plants but could obtain CO2 as a raw material anywhere on the globe, including places where inexpensive renewable energy is available. This is however still a long way off, although Christoph Gebald from the Swiss company Climeworks AG did tell the conference about a new method of separating CO2 directly from air with the help of cellulose fibres; this method can also be applied on both small and large scales. The first demonstration plant is due to come into service next year with a production of 1,000 t/yr and aims to sell purified CO2 at €800 per tonne. In 2016 a first commercial plant is to produce liquid CO2 at €200-300 per tonne, and commercial production of fuels and chemicals is scheduled to begin in 2018.
Of course, others have questioned how significant CO2-based technologies will actually be for protecting the climate and securing raw material supplies. This was a major discussion at the conference.
Michael Carus, managing director of nova-Institute GmbH, gave this illustration of the possibilities of CCU: if the European chemical industry were to meet its entire carbon needs from CO2 rather than fossil sources such as oil, gas and coal, it would use or recycle 5.5% of Europe’s total CO2 emissions, despite only being responsible for just under 2% of Europe’s CO2 emissions.