5.5 Summary and Final Tasks
Lesson 5 covered biomass pyrolysis and biomass pretreatment. Pyrolysis is a thermal treatment in the absence of oxygen and at lower temperature than gasification. The main products of interest are chars that are often used in combustion (with some of the undesirable components removed), and liquids that need to be processed further to remove oxygen functionality and add hydrogen.
The goal of pretreatment is to overcome biomass recalcitrance and improve conversion efficiency/economics. Mechanical size reduction is generally required. Several pretreatment technologies have been developed based on the use of different chemicals. They do the following:
- Low pH pretreatment: hemicellulose removal, acetyl removal, lignin solubilization and re-precipitation, increased surface area
- High pH pretreatment: lignin removal, acetyl removal, hemicellulose solubilization, increased surface area
- AFEX pretreatment: no-compositional changes, lignin alternation, cellulose decrystallization, increased surface area
- Organosolv and IL: fractionation of lignin from cellulose and hemicellulose, increased surface area
Schobert, H.H., Energy and Society: An Introduction, 2002, Taylor & Francis: New York, Ch. 4-6.
He, Brian, Department of Biological and Agricultural Engineering, University of Idaho, BEEMS Module C2, Biomass Pyrolysis, sponsored by USDA Higher Education Challenger Program, 2009-38411-19761, PI on project Li, Yebo.
Shi, Jian, Hodge, D.B., Pryor, S.W., Li, Yebo, Department of Food, Agricultural, and Biological Engineering, The Ohio State University, BEEMS Module B1, Pretreatment of Lignocellulosic Biomass, sponsored by USDA Higher Education Challenger Program, 2009-38411-19761, PI on project Li, Yebo.
Reminder - Complete all of the Lesson 5 tasks!
You have reached the end of Lesson 5! Double-check the Road Map on the Lesson 5 Overview page to make sure you have completed all of the activities listed there before you begin Lesson 6.
If there is anything in the lesson materials that you would like to comment on, or don't quite understand, please post your thoughts and/or questions to our Throughout the Course Questions & Comments discussion forum. I will check that discussion forum daily (Monday through Friday). While you are there, feel free to post responses to your classmates if you are able to help.