Catalytic conversion of lignocellulosic biomass to biofuels and bio-based chemicals using molten salts

Lignin is a waste product of the paper industry, that is usually burnt on site. But it can also be converted to a product of higher value: it can deliver the much needed carbon for various products that are currently based on fossil oils, such as chemicals and fuels. In the past years, various processes have been shown in the lab to produce biofuels and biobased platform chemicals from biomass, and in particular technical lignin. However, scaling up to industrial applications is not straightforward, due to low final product yields and the use of expensive catalysts.

In his PhD-research, Bala Sridharan developed a multi-step ABC-process. The ABC-salt approach utilizes relatively inexpensive alkali based molten salt mixtures to depolymerize biomass to liquids which is then upgraded to biofuels via catalytic hydrotreatment. Sridharan succesfully converted two different biomasses: pinewood and kraft lignin, to hydrotreated biofuels using both batch and continuous experimental setups. Process metrics such as overall liquid yields and carbon yields calculated helped benchmark the ABC-salt process to comparable processes reported in literature. The development of the concept over the course of this thesis culminated in a 100-hour demonstration of the process to continuously convert kraft lignin to biofuels with an overall liquid yield of 70 wt% (88 % carbon yield). The promising results reported here demonstrate an efficient and scalable process that will help the valorisation of biomass towards sustainable biofuels and chemicals.

See also: Flying on wood dust

Dissertation: https://hdl.handle.net/11370/d6406853-5411-4a12-82fa-24954b385715