Depolymerisation and up-cycling

We have seen that medium-temperature biomass gasification leads to the production of a gas with significant concentrations of valuable compounds. Whereas the selection of operating conditions (temperature, bed material) can steer to a limited extent the yield of these target molecules, the use of waste as feedstock boosts the content of ethylene (and other insaturated hydrocarbons) as well as BTX, as can be seen in the figure below. Ethylene, styrene and benzene are part of the original building blocks, so gasification becomes a way of recycling the monomers, but without the strict specifications on the purity of the plastic waste feedstock.

The high yield of ethylene, styrene, etc. when using plastic waste-containing feedstock creates new way of recycling (upcycling) the monomers / depolymerization. Thus, this leads to a novel approach - converting waste into aromatics and adding biomass to the blend to close the aromatic cycle.

Closing the aromatics cycle with biomass/waste

Bio-aromatics production on the long term is expected to be part of an integrated large-scale process where aromatics, olefins, biofuels and bio-energy will be produced as co-products with overall high efficiency. It is expected, that contrary to conventional refinery plants based on mineral oil, in a bio-refinery energy is an important product. Since the energy market (power, fuels, heat) is dozens of times larger than the market for (bulk) chemicals, energy creates the scale that is needed to have the economy for chemicals such as the aromatics. Bio-energy and bio-chemicals will go hand in hand: bio-energy creates scale and efficiency, whereas bio-chemicals create necessary income.