Study of biomass combustion characteristics for the development of a catalytic combustor/gasifier

The research reported here explored, a "new" approach to biomass energy conversion for small-scale process heat-applications. The conversion process uses close-coupled catalytic. combustion to burn combustibles in effluent generated by primary combustion or gasification of biomass fuels. Computer control of primary and secondary air flow rates allow control of the devices output power while maintaining fuel-lean or stoichiometric conditions in the effluent entering the catalytic combustion zone. The intent of the secondary combustion system is to ensure "clean" exhaust (i.e., promote complete combustion). A small-scale combustor/gasifier was built and instrumented. Characteristics of combustion were studied for three biomass fuels so that primary and secondary air flow control strategies could be devised. A bang-bang type controller was devised for primary air flow control. Secondary air as controlled based on feedback signals from an inexpensive automobile exhaust gas oxygen sensor. The control strategies and catalytic combustion were implemented on prototype combustor/gasifier and the device was tested with good results. Power turn down ratios of 4 to 1 and 3 to 1 were achieved. The zitconia-type automobile exhaust gas oxygen sensors adapted well to the combustion environment of biomass fuel, at least for short periods (long term durability tests were not conducted). The secondary air control system was able to maintain fuel-lean flows for the most part and, the secondary combustion system provided reductions of approximately three fourths in carbon monoxide emissions.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1985

Author dc:creator

• Dody, Joseph W.

Chair dc:contributor.committeechair

• Jaasma, Dennis R.

Committee members dc:contributor.committeemember

• Leonard, Robert G.
• Reinholtz, Charles F.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-06102012-040156

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/43039