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Title: Biogas-fuelling of small engine-alternator set for rural applications

Conference · · Proc., Intersoc. Energy Convers. Eng. Conf.; (United States)
OSTI ID:5723510

The fuelling of a portable engine-alternator set with simulated biogases (mixtures of methane, CH/sub 4/, and carbon dioxide, CO/sub 2/) was investigated. The only modification required for gas-fuelling of the engine (a normally petrol-fuelled, side-valve machine rated at 5,2 kW mechanical output) was the fitting of a simple venturi-type gas feed adaptor. Hand-starting and acceptable running of the engines was possible with biogasses containing up to 31 vol % CO/sub 2/. Replacement of petrol with pure CH/sub 4/ resulted in a 17 % loss of maximum power output. Increasing CO/sub 2/ content of the gas led to further losses of maximum power, with a 35 % loss at 31 % CO/sub 2/. Gas consumption for pure CH/sub 4/ was 1,65 normal m/sup 3//h at 2,2 kA electrical power output (the maximum for this fuel); for biogas of 31 % CO/sub 2/ the corresponding figures were 2,15 m/sup 3//h and 1,65 kW. The overall efficiency of the unit (electrical output divided by calorific input) was higher with biogas-fuelling than with petrol; also the engine ran 80 to 100/sup 0/ C hotter and with reduced carbon deposits in the combustion chamber. The loss in power on fuelling with biogas, instead of petrol, could be partially offset by increasing the compression ratio of the engine.

Research Organization:
School of Mechanical Engineering, University of the Witwatersrand, Johannesburg
OSTI ID:
5723510
Report Number(s):
CONF-840804-
Journal Information:
Proc., Intersoc. Energy Convers. Eng. Conf.; (United States), Vol. 2; Conference: Intersociety energy conversion engineering conference, San Francisco, CA, USA, 19 Aug 1984
Country of Publication:
United States
Language:
English