Prospective LCA of a biorefinery concept for production of bulk and fine chemicals
Konferensbidrag (offentliggjort, men ej förlagsutgivet), 2018
The move from a fossil-based to a bio-based economy requires the development of new technologies and process concepts for the production of bio-based energy, chemicals and materials. A biorefinery concept can be designed by integrating such technologies, and can thus provide a viable alternative to produce bulk and fine chemicals. This paper presents a prospective life cycle assessment (LCA) of a novel biorefinery concept, in its early stages of development, for the combined production of adipic acid from forest residues (GROT) and of lutein from micro-algae.
Adipic acid is a high-volume chemical (yearly production of approx. 2.3 million tonnes) and is primarily used for the production of nylon-6,6. Conventional adipic acid production from fossil resources is characterized by significant emissions of N2O. Lutein is a high added-value chemical used in the food and pharmaceutical industries, and is conventionally produced from marigold flowers. Furthermore, lignin is an important by-product. The biorefinery concept in this work consists of the pretreatment of GROT, the separation of lignin, and the hydrolysis and fermentation of the pretreated GROT to adipic acid which is then separated and purified. Water, nutrients and CO2 flows from the adipic acid production can be connected to the algae production. Anaerobic digestion is used in this concept to produce biogas from waste streams.
Multiple design variants of the biorefinery concept, which is the foreground system, were modelled and simulated based on both experimental and literature data. These variants aimed at narrowing down uncertainties about, for instance, the most suitable GROT pretreatment options, available technologies for anaerobic digestion, and possible routes for further processing of lignin. The data and information resulting from the simulations of the design variants were used to compile the life cycle inventories of each of these variants. The assessment of these variants provides a range for the future environmental performance of the biorefinery concept based on design choices and process conditions. Furthermore, scenarios for future energy systems were considered in order to assess the influence of the background system on the environmental performance of the biorefinery concept. The results provide more relevant information and valuable insight to industry and policy decision makers in order to guarantee an environmentally benign future production of bulk and fine chemicals.