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close this bookLow Cost Charcoal Gasifiers for Rural Energy Supply (GTZ, 1994, 49 p.)
View the document(introduction...)
View the documentForeword
View the document1. What? Gasifiers?
View the document2. Gasification in recent history
View the document3. Small gasifier-engine systems for rural energy supply in developing countries
close this folder4. The trouble with ''field applications''
View the document4.1 Weak points of gasifier-engine-systems
View the document4.2 The problem of ''acceptance''
close this folder5. Lowering plant costs by ferrocement construction
View the document5.1 What makes a gasifier expensive?
View the document5.2 The construction of a ferrocement gasifier
close this folder6. Technical performance of the ferrocement gasifier
View the document6.1 Design details
View the document6.2 Performance data
close this folder7. Derived technical demands for field application of gasifier-engine systems
View the document(introduction...)
View the document7.1 Issues in engine operation
View the document7.2 Typical applications
View the document7.3 Repair and maintenance of the ferrocement gasifier
close this folder8. Non-technical aspects of gasifier operation in the field
View the document(introduction...)
View the document8.1 Pro's and contras of the ''do it yourself'' approach
View the document8.2 Community plant or private ownership?
View the document8.3 Qualification and motivation of the operator
View the document8.4 Implications of non-technical issues
close this folder9. Economics of gasifier operation
View the document9.1 How to compare gasifier costs
View the document9.2 Case study: Comparative costs of gasifier installations in Argentina and Malaysia
close this folder10. Concepts of future dissemination of small gasifier-engine systems
View the document10.1 Perspectives of biomass energy
View the document10.2 The actual limits of gasification technologies
View the document10.3 Substitution of firewood by other biomasses
View the document10.4 Framework for establishing gasification technologies
View the documentReferences

4.1 Weak points of gasifier-engine-systems

It became obvious in the late eighties that despite the lively interest in the gasifier technology during the past 10 years no "dissemination" worthwhile mentioning had taken place. The dominant argument to explain this was the claimed "technical immaturity" of the systems. This requires some comments.

It is typical for gasifiers employed in developing countries over the last years that these systems had mainly been developed by research institutions and universities. These plants (all of them prototypes) showed technical shortcomings as soon as they were tested under the rough conditions of "field application". In the end their failure consisted of a sum of mistakes made in details, which only came to light when the favourable conditions of lab application (defined and constant fuel quality, good possibilities for repair and optimization, qualified and motivated operators) were missing: Bad bunker flow of insufficiently prepared fuel, unoptimized container geometry, fast wear of parts subjected to varying temperature, wear of scalings, problems of corrosion, insufficient gas cleaning were wide-spread defects [3].

On the basis of subsequent documentation quite often it can also be reconstructed that grave mistakes have been made in the adaptation between gasifier output and engine size (usually the cylinder volume of the engine was chosen too small, thus preventing the gasifier from reaching the necessary operating temperature). Often there also existed wrong ideas about the application purposes, to which gasifiers might generally be suited or unsuited.

More will be said on the technical aspects later in this paper. First, however, another approach is chosen. The most commonly used argument of the allegedly existing technical "immaturity" of those gasifiers available certainly often holds true for some wellknown cases, but it can no longer be accepted as the sole reason for the hitherto limited dissemination. Technical problems are almost always solvable, once they have been recognized. Meanwhile, knowledge about gasifiers should be sufficient to realize good technical performance. But still the reputation of this technology is not too good.