|Low Cost Charcoal Gasifiers for Rural Energy Supply (GTZ, 1994, 49 p.)|
|6. Technical performance of the ferrocement gasifier|
In table 1, data are listed which were measured at the operation of a standardized gasifier in ferrocement construction, designed for a power range of 2-10 kW. These data are derived from test series, carried out in the laboratory of FLEUS (Bremen University). More detailled data sets can be derived from the project report for BMFT [ 12].
The performance data largely depend on the mechanical resp. electrical load, connected to the engine. The values in table I resulted when a 6-cylinder engine with 2.0 cylinder volume and a speed of 2,500 rpm was connected, linked to a 3-phase alternator powering an electrical load (stove plates).
Diagr. 1 and 2 show very clear that the "nominal operation" of the gasifier has to be defined clearly. In diagr. 1 the specific fuel consumption of the ferrocement gasifier is plotted for three load situations (2, 6 and 10 kW). At 10 kW (which is a bit below the maximum power of 12 kW, which can be reached with he 2 liter engine) the fuel consumption per kWh is much less than at the load 2 kW. This is reflected as well in the overall efficiency of the system (the relation of usable electric energy to the energy content of the fuel): The efficiency is much better on 10 kW than on 2 kW.
This tendency is obviously common to all types of gasifiers and has to be recognized:
A gasifier has a narrow range of optimum performance. A deviation from the optimum working condition results in less efficient use of fuel, less operational stability, and less economic viability.