Experimental and modeling aspects of producer gas engine

Biomass gasification technology offers a cost effective option of power generation for a wide variety of applications including distributed power generation. In most cases a reciprocating engine forms the prime mover. The work reported here uncovers some of the misconceptions associated with the usage of producer gas, a lower calorific gas as a reciprocating engine fuel. This paper particularly addresses the use of producer gas in reciprocating engines at high compression ratio (17:1), which hitherto had been restricted to lower compression ratio (up to 12:1). The current work clearly indicates to the breakdown of this compression ratio (CR) barrier and it is shown that the engine runs smoothly at CR of 17:1 without any tendency of knock or auto-ignition. These experiments were conducted on a spark-ignition engine converted from a diesel engine at a CR of 17. Experiments at varying CR (17 to 11.5) have established the benefits of operating the engine at higher CR in terms of lower de-rating and better efficiencies. These experiments also established the optimum parameters, namely the minimum advance for brake torque and the corresponding equivalence ratio for maximum power. It was also found that the exhaust emission from the producer gas fuelled engines meet the emission norms without using emission control devices. Furthermore, a zero-dimensional model has been formulated using wrinkled flame theory for flame propagation to estimate output of producer gas engines.