Research Project Summary Information
The goal is to use Hot Water Extraction™ followed by steam explosion to reduce or eliminate the need for conventional grinding when making wood pellets. (28244)
Applied Biorefinery Sciences LLC
Wood chips are often made into pellets before burning because they store and transport well, and they burn more cleanly and uniformly than chips. The first major step in manufacturing pellets is to use a hammermill to grind wood chips into smaller pieces for drying and storage. Then, a second grinding step further reduces the size of the material immediately prior to forming the pellets. These two grinding steps are energy intensive.
Other ways exist to reduce wood to smaller pieces. For decades, paper manufacturers have used “steam explosion” to reduce wood chips into a more fibrous form prior to paper making. Steam explosion is a proven size-reduction technique; the results are a function of the temperature at which the pressure vessel is opened, following the cooking process.
Steam explosion can be combined with other processes. Applied Biorefinery Sciences LLC has a patent-pending complementary process called Hot Water Extraction. This process uses hot water to rinse out some of the more soluble components of wood, leaving behind a material with improved properties for pellet manufacturing and creating a side stream of chemicals: fermentable wood sugars. Hot Water Extraction, optionally followed by steam explosion, may reduce the need for grinding wood chips during pellet manufacturing, but since combining these two steps for this purpose is a new idea, the best operating parameters are unknown.
The goal is to use Hot Water Extraction, followed by steam explosion, to reduce or eliminate the need for conventional grinding when making wood pellets. Objectives include design of the extractor vessel; construction of the vessel at a fabricator; installation of it at the State University of New York College of Environmental Science and Forestry (SUNY ESF); use of it to steam explode wood chips that have first been subjected to hot water extraction, while iteratively testing pressure release temperatures and residence times; measurement and comparison of particle size distributions of each run with those found with conventional grinding of either green or dry wood; use of the particle size distribution information to determine optimal pressure release temperatures and residence times for elimination or reduction of grinding; performance of metallurgical coupon tests that use the temperature, pressure, and acidity conditions found in hot water extraction to determine the durability of metals that could potentially be used for extractor vessel construction; analysis of metal durability with respect to cost; brief discussion of existing literature regarding possible markets for the sugar co-product; and estimation and comparison of the overall avoided electricity consumption and thermal requirements of pellet manufacture, using the new process with pellets made with conventional grinding of green or dry wood.
A successful project could reduce the amount of hammer-mill grinding needed in a typical pellet manufacturing plant, thereby resulting in a 15-20% reduction in overall electricity consumption for wood pellet production. At full scale, cost savings of $6 per ton of wood pellets is targeted. The company has tentative plans to build and operate at least four biorefinery complexes in New York State that would produce marketable wood sugars and other coproducts in conjunction with fuel pellets and other wood products.
Applied Biorefinery Sciences LLC
4736 Onondaga Boulevard 451
Syracuse, NY 13219
SUNY College of Environmental Science an
NYSERDA Contact Information
R&D - Environment & Energy Res