Supercritical production of extract from poplar containing bioactive substances – An economic analysis

The concept of a biorefinery entails, the multi-product use of biomass, which is processed to high quality products and afterwards the production residues are used for energy or other purposes. The maximum utilization of resources and the minimum impact on the natural environment are the two essential arguments attesting to the validity of this concept. Beside the environmental considerations, another important factor is the profitability of a production process, which underlies the market competitiveness of products. The main objective of the study presented in this article has been to analyse the life cycle costs and profitability of a chosen chain of values of two bioproducts: extract from poplar biomass and pellet from post-extraction residues, processed according to the concept of a biorefinery. The input raw material was biomass of poplar (Populus nigra × Populus maximowiczii (L.) Henry) grown in short rotations. The main bioproduct was dry extract, while post-extraction biomass was used to produce an energy co-product, which was pellet. The main bioproduct, generated by supercritical extraction, is an innovative ingredient of high-quality bioproducts, e.g. in veterinary medicine or in anti-inflammatory drugs. In this study, production costs in a chain of values composed of dry extract and pellet from poplar biomass were determined. The analysis included the determination of capital expenditures (CAPEX) and operating expenditures (OPEX) as well as life cycle costs (LCC). In addition, a production profitability analysis was made, where the profitability thresholds for production of dry extract and pellet were calculated, and the following investment profitability indicators were determined: net present value (NPV), internal rate of return (IRR), profitability index (PI) and discounted payback period (DPBP). The scope of analyses comprised the following system sets: subsystem I including expenditures and income related to the production of poplar chips in an annual cycle; subsystem II contained costs of transport to a drying plant, costs of drying and grinding as well as costs of transport to the next subsystem; subsystem III, known as a biorefinery, comprised expenditures and income related to the production of extract as well as costs and income related to the production of pellet. The highest capital expenditures (CAPEX) were incurred by the purchase (73%) and installation (22%) of a plant for supercritical extraction. In turn, the highest operating expenditures (OPEX) consisted of labor costs (59%) and costs of raw materials and utilities for the supercritical extraction process (37%). Production of extract and pellet was profitable.