Non-thermal Plasma Gasification System Cleans Up Syngas

April 16, 2019

Biomass gasification, which converts organic material into valuable gaseous product called syngas, is one of the efficient thermochemical process for the production of biopower, biofuels, and chemicals. However, one of the major problems of biomass gasification is the removal of tars from syngas. Tars can block the pipes and reduce the engine performance. Several approaches have been adopted to overcome the tar challenge, but are either very costly or generate hazardous by products.

Dr. Ajay Kumar, Associate Professor of Biosystems and Agricultural Engineering (BAE), Oklahoma State University (OSU), collaborated with Dr. Gerardo Diaz from the School of Engineering at University of California-Merced (UC-Merced) and Dr. Prakash Bhoi, former Postdoctoral Fellow at BAE, OSU, to develop a unique syngas cleaning system.

The research team from UC-Merced developed and incorporated a non-thermal plasma (NTP) generation system to the existing pilot scale gasifier at OSU to significantly reduce tars.

“Our results showed that NTP improved the syngas composition by increasing hydrogen content (from 4.3 to 6 vol. %) and decreasing heavy gaseous hydrocarbons”, Kumar said. “Non-thermal plasma significantly reduced syngas tars from 25 to 3 g/NM3 by ionizing tar molecules when tested with a syngas flow rate of about 0.5 standard cubic feet per minute,” Kumar added.

“Electricity consumption was also reduced because NTP typically operates at relatively low temperatures (much less than 1500 oC),” Kumar said. “Removal of tars and reduction of electricity consumption is expected to improve the economics of the gasification with plasma gas clean-up technology”.

The successful development and commercialization of this technology will reduce the need of secondary syngas cleaning methods and will economically benefit small-scale commercial application of biomass and waste gasification for electricity generation and fuel production.

Funding of this project was provided by the U.S. Department of Agriculture-National Institute of Food and Agriculture (USDA-NIFA) through the South Central Sun Grant Program.