Bio-based vs. petrochemical production of commodity chemicals

Lignocellulosic biomass can be converted, for example, via hydrolysis to carbohydrates, gasification to syngas, pyrolysis to bio-oil, and anaerobic digestion to biogas. In each case, further conversion into commodity chemicals can proceed by catalytic or fermentative methods.

While most overall routes are at an early stage of development, there is a need to identify which might be able to outcompete fossil-based routes. Therefore, for all types of current commodity chemicals, the perspective of replacing fossil-based by biomass-based production is discussed.          

It is assumed that feedstock costs will keep dominating costs in mature chemicals production processes. Each consecutive product will be more expensive due to feedstock costs multiplied by a factor due to other processing costs and profit. Consequently, routes should use cheap raw materials, have an optimized yield on key raw materials, and consist of the minimum number of conversion steps.  

Considering raw materials, it is assumed that the prices of petrol and biomass prices will remain coupled via the energy value of transportation fuels.

It will be shown that these assumptions exclude naphtha derivatives such as lower olefins and BTX to be produced competitively from biomass, irrespective of the route or process type. Biomass-based production will be competitive for relatively oxidized products, if they can be produced via a very small number of conversion steps, such as by fermentation. The overall extent of oxidation of a route should not surpass the requirements of overall stoichiometry and thermodynamics. This also minimizes energy use, CO₂ production, and equipment size.