Use of Stirling engines or gas turbines with producer gas
In addition to the use of producer gas with internal combustion engines, other possibilities are the combination of gasifiers with gas turbines or with Stirling engines. Because high inlet gas temperatures aid the thermal efficiency of gas turbines, these in principle present an attractive option for converting hot producer gas into mechanical and/or electric power. However, the current state-of-art of gasifier as well as turbine technology prevents their use. Gas turbines are very sensitive to dust, especially at high inlet temperatures, and it is doubtful if gas quality requirements can be met with the filtering systems described in section 2.6.
Another problem stems from the sensitivity of current turbine vanes to corrosion by alkaline vapours (Na, К and Ca) which are usually present in tiny amounts in producer gas. An
optimum system would require a pressurised gasifier, which would add considerably to cost and complexity and probably will only be economic for very large installations.
Beagle (6) mentions the possibility of using Stirling engines in conjunction with gasifiers especially in micro scale applications. Stirling engines in this power range are now becoming commercially available.
Because of a number of advantages as compared to the use of internal combustion engines (low maintenance, high efficiency, low lubricant consumption etc.) this concept should be further evaluated and tested.