Process design and scale-up study for the production of polyol-based biopolymers from sawdust

Abstract

Sawdust is a by-product of the forestry industry which can be used as raw material for the production of added-value bio-based chemicals, leading to the development of a circular economy based on this organic resource. One of the most promising approaches for the reuse of sawdust is the production of polyols, which in turn can be used as raw material for the production of biopolymers. In this work, this process is analyzed to develop a sustainable alternative for the processing of forestry waste, obtaining biodegradable polymers than can be re-incorporated into the production cycle. A conceptual design and scale up of the process for the production of polyols out of sawdust and glycerol is developed based on experimental data. The process has been designed following the premise of being as environmentally sustainable as possible, but using simple equipment feasible to be deployed and operated by the timber facilities. Therefore, sawdust is used as raw material and energy source. The process is modeled using an equation based approach to perform a techno-economic analysis of it. The proportions of sawdust devoted to polyol production and thermal energy generation and power consumption are determined, as well as capital and operating expenses. In addition, a scale-up study to determine the effect of the economies of scale on the economic performance of the process proposed is carried out, as well as a sensitivity analysis in order to assess the influence of the raw materials price on the production cost. The results show that, for usual market prices of glycerol and starch, the production cost ranges from 0.10 to 0.66 USD per kilogram of biopolymer produced.