Covestro to expand CO2-using processes

COVESTRO is working to expand its innovative process for producing plastics from CO2 – including the volume it makes, the proportion of CO₂ it uses, and the range of chemicals it can produce.

The process which started up last year uses CO₂ to replace 20% of the oil-derived propylene oxide conventionally used to produce polyols – a precursor in the production of polyurethane foams. At a press meeting held in London yesterday, Covestro CEO Patrick Thomas discussed the progress of the plant which is currently producing 5,000 t/y of polyols. The resulting foam is being used today in mattresses and car seats and the company is now discussing deals to license the process to polyol producers in a bid to propel the technology to a higher level.

“The next scale is probably 100,000 t/y – so that would be the next logical step,” said Thomas, who noted that he expected to be on track to achieve that level of output in the next five years. He added that while the drop-in product technically performs the same as the material it is replacing, the confidence of using a CO2-based product still has to be built within the market.

“We have said we’ll license the technology and we have one or two companies who are interested in building jointly larger-scale facilities, so that is where we are at the moment.”

The company also plans to double the proportion of CO₂ used to make polyols but explained that moving away from the 20% used today will require the company to overcome process and chemistry challenges.
“43% is the limit set by chemistry,” he said, but noted it was important to get closer to 40% because the “economics just look so much better”.

Work is also underway to expand the range of chemicals that Covestro can make using CO₂ feedstocks.
“We did a project with a professor at Aachen University to look at the thermodynamics of all chemical processes and to see where you could drop in CO₂ instead of other feedstock. Around half of all the processes in the chemical industry can be done using CO₂.”

The company has 30 postdoctoral researchers at the Dream Production centre in Aachen University in Germany where its commercial polyol catalyst was developed, working on how to use CO₂ to produce rigid foams for use in insulation and construction products. It has also proved that it can use CO₂ and another greenhouse gas methane to produce rubbers.

Given the experience of developing the polyol catalysts, however, Covestro is allowing its researchers the latitude to innovate.

“You don’t want to be too directional because we actually started them on working out how to make polycarbonate from CO₂. They came back saying: ‘We don’t know how to do that, but we found a way to make polyurethane’. So you don’t want to be too directive as you never know where they are going to go.”

Away from using greenhouse gases, but still focussed on the use of waste, the company plans by 2025 to produce aniline, the feedstock for MDI, from a bio-based feedstock. Thomas was unable to disclose too many details at this stage but what he was able to share was the following: a pilot unit is being built that uses an engineered bacteria to convert non-food plant waste into an intermediate that would then be converted through chemical catalysis to aniline.

“The real breakthrough came by building together a biosynthesis route with a catalytic chemistry route; getting those two bits to cross over in the middle with the right intermediate.”