Upgrading of biomass: alternative ways for biomass treatment

Sammanfattning: As the world population and wealth increases it is necessary to look for sustainable alternatives to guarantee modern living standards. With depleting resources and the threat of global warming, biomass is emerging as a promising alternative to lay the basis for a bio-based sustainable economy. New biomass upgrading trends lead to the concept of biorefinery, where a large array of chemicals, fuels and energy can be produced, maximizing the value of biomass. The aim of the present work is to find industrial biorefinery processes developed to produce chemicals and fuels but that at the same time yield considerable amounts of combustible by-products that can be employed as a fuel in Vattenfall´s power plants. This paper is focused on lignocellulosic biomass as a feedstock. A comprehensive review of existing technologies at different maturity levels to upgrade biomass is done. The review covers biomass pretreatment operations, thermochemical, chemical and biochemical processes. It starts by describing simple unitary operations that are used to build complex biorefinery systems. A selection of some of the possible biorefinery schemes is briefly described. After listing and describing different biomass upgrading processes, three process were selected for further analysis. Two biorefinery processes with different maturity levels were selected: the Biofine process and Lignocellulosic Ethanol. A process to produce a solid fuel, Hydrothermal Carbonization, was selected as well. The process selection was done according to Vattenfall´s interests. The three processes selected were further analyzed performing a mass and energy balance. To achieve these tasks, a model of the processes using Microsoft Excel was done. The estimation of the product yields and energy usage was done assuming woodchips as a feedstock. Sensitive operating conditions where the energy usage can be improved are identified. After the mass and energy balance an economical evaluation by means of OPEX and CAPEX calculations was done to determine the profitability of the processes. Opportunities for each process are identified and conditions to achieve or improve the profitability of the processes were pinpointed. The biorefinery concept is an emerging technology and as any new technology there are obstacles that need to be surpassed for being introduced into the market. A discussion on these issues was made as they will drive R&D efforts, industrial development and policies in the upcoming years. The importance of innovation in technology through R&D and market push policy measures was analyzed as it plays a fundamental role in the industrial dynamics of emerging technologies. Synergies and cooperation between the pulp and paper, forest, petrochemical and energy industries should be seek to tackle the challenges these technologies present and endorse a sustainable bio-based economy.