An evaluation of performance of automatically operated multi-fuel downdraft gasifier for energy production

Till now mainly commercially available downdraft gasifiers are constructed and developed for a clean and well prepared woody biomass, like wood chips. However, recently, wastes, such as sewage sludge, farm litter or harvested agricultural waste, are of great interest to end users. Desirable that facility like gasifiers could be able to recognize different waste types and properly adapt to the required processes. per presents the results of experimental investigations in a downdraft gasifier using different types of fuel and waste to compare process performance and estimate the potential to gasify various feedstock types in a single fully automated device. Several types of feedstock were used in investigations: wood chips, pellets from wood, rape straw, poultry litter, dried sewage sludge and their mix with wood. The experimental analysis evaluates and reveals the differences in process parameters such as temperatures, pressure drop of a bed, products composition and yields, process efficiencies associated with the gasification of various feedstock. Established, that the proper automation of multi-fuel downdraft gasifier should contain a residual discharge and fuel feed control according to optimized the pressure value, whereas air flow supply automation is possible due to staged air adjustments and must be followed by a char discharge system.