Wood-Based Biorefinery: Technological Overview and Benefits

Biomass has been an important energy source for mankind since the beginning of civilization. Ligno-cellulosic biomass is the most abundant organic source on earth, with an annual production in the biosphere of about 170 billion metric tons. Taping into the chemical energy of biomass and reclaiming the historically important position for biomass in energy and transportation is imperative to the sustainability of world economy. Developing a biorefinery technology based on wood facilitates to the development of a bio-based energy economy, whether the final intent is the use of forest biomass alone, woody biomass crops, perennial grasses, or agricultural residues, all of which are beneficial to rural economies. The SUNY ESF biorefinery, a hardwood focused water-based technology, includes five main components or essential elements, namely: 1) hot-water extraction; 2) hydrolysis of hot-water extracts; 3) fractionation of hydrolyzates or wood extracts; 4) conversion of five- and six-carbon sugars to ethanol, butanol, bioplastics, or other products; 5a) pulping of hot-water extracted woodchips followed by bleaching and papermaking; 5b) burning of the hot-water extracted residual chips and organics for CHP use; 5c) pelletizing the hot-water extracted residual chips together with the lignin separated from wood extracts; or 5d) production of fiber board from the hot-water extracted woody biomass. Hot-water extraction In the absence of mineral acids and bases is preferred due to its ability to maintain high product values. Extraction and hydrolysis produce xylo-oligomers, acetic acid, sugars, and other (race compounds. The production of acetic acid makes the process autocatalytic as acid catalyzes extraction and hydrolysis. Membrane fractionation can be applied to purify and concentrate sugars and acetic acid. There is an enhancement in manufacturing processes and several products based the extracted chips, most notably in pulping and bleaching processes. Therefore water based technology is preferred for a wood based biorefinery. Developing a wood based biorefinery is the starting point for a biomass biorefinery. Since wood is available year-round in forested regions, wood provides assurances for continuous industrial operation of a biorefinery. The "catch and release" scheme of carbon utilization is of great value to the environment and development of a sustainable economy. In this presentation, we will be focusing on the five to eight essential elements of a biorefinery.