Performance of a microturbine partially fired with syngas from a biomass fuelled reformer

When solid biomass is externally combusted for the production of power like in steam cycles, Organic Rankine cycles or Stirling engines the conversion efficiencies are known to be limited. It is however possible, as shown in previous work of the authors, to combine the advantages of external firing with the potential high efficiency of gas turbine cycles through co-utilization of natural gas and biomass. Heat from a biomass combustor can be utilized to partially reform natural gas and steam into a hydrogen rich syngas. This syngas can be used in most common gas turbine cycles while maintaining high efficiencies and avoiding costly technological developments.
To demonstrate and proof this concept, a pilot and test facility is being built around an existing microturbine in the university laboratory. Part of the natural gas will be reformed to syngas and used in the engine. This will have a profound effect on engine operation reflected in the marginal efficiency of the biomass - because of the high water and hydrogen content of the syngas and the variable shaft speed of the microturbine. In this paper. results of performed off-design calculations are presented and the effects of partial primary steam reforming on microturbine performance are discussed.