CO2 as Chemical Feedstock From CO2 to Plastic Foams: The Stuff That Dreams are Made of?
Dream Production is a new approach to making stuff that dreams are made of (at least if you are a chemist): Industry and scientists are working together on a project to produce chemical feedstock from CO2 which is extracted from power station flue gas emissions. The underlying reaction is revolutionary, but there is uncertainty surrounding the economic viability of the process. It remains to be seen whether this time the vision is more than just a dream.
This chemical reaction could mean the rehabilitation of a harmful substance. CO2, infamous as an industrial waste and greenhouse gas, could become a feedstock source for the chemical industry. Besides cutting harmful emissions, the new technology could also reduce oil and gas consumption. Plant photosynthesis removes all doubt that such a reaction is possible: All of the carbon needed for herbal cell growth is extracted from atmospheric CO2. However, there is one huge stumbling block associated with this fairy-tale chemical reaction: CO2 is a relatively stable molecule that is not particularly reactive.
So far, this low reactivity has made recovery of carbon from waste gas very unattractive. Now the chemical industry has set its sights on this dream reaction. Bayer Material Science is investing 15 million euros to build an initial industrial-scale (5000 t/a) production line in Dormagen, Germany, where CO2 will be used to produce polyols, typical precursors for polyurethane (PUR).
New Life for an Old Idea: CO2 as a Raw Material
The idea of using CO2 as a feedstock for plastics production has been around for more than 40 years and is resurrected during each and every oil crisis. The main problem is, however, that the molecule’s low reactivity makes the process economically unviable. Without some outside help, the reaction does not get off the ground. Having this in mind, the researchers at Bayer who are working on the waste gas utilization are concentrating their efforts on the development of a suitable catalyst.
The Chemical Industry’s Holy Grail?
“The reaction is more or less the Holy Grail of the chemical industry,” reported Dr. Karsten Malsch, Bayer’s Venture Manager for CO2 polyether. “Despite all of the research so far, no way has been found of using CO2 in larger molecules.” The dream reaction remains a hard nut to crack: The problem has haunted researchers for more than 40 years, but now, a solution could finally be at hand.
Has the Holy Grail finally been found? Malsch seems convinced, but the road has been long: The Bayer team, working with researchers at the CAT Catalytic Center, has tried more than 200 different substances before discovering a zinc-based catalyst. Now, for the first time, the vision of making polyols from CO2 and propylene oxide, an oil-based precursor, appears to be within reach.
The leap from the lab environment to industrial-scale production was the result of teamwork: Five partners from the scientific community and industry joined forces in the Dream Production project, which received government funding. Bayer Technology Services, Bayer Material Science, the power utility company RWE, the RWTH Aachen University and the CAT Catalytic Center, a research institution which is located on the RWTH campus and is jointly run by the university and Bayer, joined forces in the research consortium.
In the process, a pilot line was constructed at Bayer’s main site in Leverkusen in 2011. The CO2 for these trials, supplied from an RWE Niederaußem power station near Cologne, was reacted with propylene oxide to produce a high-viscosity, colorless mass, namely polyol.
Kick-Off for a Dream
Now, following three years of pilot production, the time has come to scale up the process: A production line with a capacity of 5000 t/a will be built at an existing Bayer polyether plant in Dormagen. “The production volumes are relatively modest. The main emphasis is on further development of the technology,” explained Malsch, who is in charge of the Dream Production project.
The fact that the plant in Dormagen is located at an integrated chemical site enables Bayer to exploit significant synergies. The CO2 needed for production is supplied as a waste product from a nearby Kemira ammonia plant. Starting in 2016, the plan is to begin using polyol produced on the line to make polyurethane foam for products such as heat insulation, shoes, auto parts, mattresses and furniture cushions.
A Better CO2–Balance Can Be Achieved
“Initially, production will be operating at a loss. We are investing up front, but over the medium term we expect to make money from the polyurethane when we ramp up production to the next level.” Bayer claims that the quality of the new material is at least as good as that of feedstock produced using conventional techniques, and there is an added sustainability dimension: By using a certain amount of CO2, production is no longer completely dependent on oil-based propylene oxide, thus reducing oil consumption. At any rate, the CO2 balance of the new process is better compared to the conventional production technique.
Annual worldwide demand for PUR currently stands at 15 million tonnes, making this is a persuasive argument. Moreover, the material has significant additional potential. When you factor in the huge growth of the emerging economies, the polyurethane market is expanding at an annual rate of 5 %.
From waste Gas to Plastic: Foundation on Foam
Will it be possible to make climate-friendly mattresses and insulation panels in the future? Maybe not quite. Utilization of CO2 could help to reduce oil consumption, but there will still be a need for fossil-based propylene oxide. Bayer believes that the savings will be in the region of 20 %. The energy needed to break down the gas also has to be factored in.
Will this really make industry any “greener” given the 147 million tonnes of CO2 that belched out of the chimneys of Germany’s large lignite-fueled power stations in 2012? Initial figures generated by RWTH Aachen are reassuring. The scientists report that the new process consumes less energy and generates lower CO2 emissions over the full lifecycle.
Can CO2 Utilisation be Coupled with renewable Energy
5000 tonnes may not sound like much but it is a start. The technique could become genuinely lucrative in combination with renewable power generation. Energy sources like wind are extremely fluctuating, yet an electrolysis process could make it possible to store energy in form of hydrogen (see box). That, however, may be as far off as waste gas based PUR.
“Of course that is not enough to meet market demand,” admitted Bayer Material Science Executive Board Chairman Patrick Thomas. “However, we have a patented process and it remains to be seen whether we will be the sole producer of this polyol. We also have the option of licensing the technology.”
There is a general feeling of satisfaction: Bayer is pleased at the positive response to the technology and the opportunity to reduce oil consumption. The RWTH Aachen has demonstrated its credentials in basic research, and RWE hopes to use the technology to clean up power station emissions. Whether the waste gas foam becomes economically significant or remains the stuff of dreams remains to be seen. There is now, however, reason to dream, maybe even on a mattress made from CO2.