Biomass Feedstock Engineering—Densification and Moisture Management

Vance Morey, Professor
Nalladurai Kaliyan, Graduate Student
Greg Cuomo, West Central Research and Outreach Center, Morris, MN
Mike Reese, Renewable Energy Coordinator, West Central Research and Outreach Center, Morris, MN

Funding Sources

University of Minnesota Initiative for Renewable Energy and the Environment (IREE)

Objective

Define systems to collect, store, preprocess (dry and densify), and deliver biomass (cornstover, perennial grasses, or legumes) of increased density and consistent quality to end-users.

Need or Impact

There are multiple sources of agricultural biomass with several potential uses. These sources have different characteristics, costs, and environmental benefits associated with them. One of the challenges is to make biomass from multiple sources more consistent and convenient for multiple end users. Some of the factors to consider include sources, end uses, collection, processing, storage, product characteristics, environmental benefits, economics, and marketing. Increased use of biomass as fuels for heating, fuels for generating electricity and process heat in a combined heat and power application, or feedstocks for liquid fuels and chemicals will provide environmental benefits by replacing fossil energy sources and strengthen the economic base of rural communities.

Project Status

Corn stover and switchgrass are often harvested in low-density baled form, resulting in significant handling, storage and transportation costs. Densification characteristics of corn stover and switchgrass under single and multiple compression cycles were studied under laboratory conditions at several pressures and moisture contents. All tests were conducted at room temperatures. Higher densities and greater durability were obtained for corn stover compared to switch grass at the same conditions. Multiple compression cycles provided modest improvements in density and for both corn stover and switch grass. Multiple compression cycles improved the durability for cornstover; however, switchgrass briquettes had zero durability under both single and multiple compression cyles.
The next steps are 1) laboratory scale briquetting at elevated temperatures to determine if durability can be improved, and 2) evaluation of performance using pilot-scale roll compaction/briquetting equipment.