Evaluation of dried compost for energy use via co-combustion with wood

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Date
2018Author
Malaťák, J.
Bradna, J.
Velebil, J.
Gendek, A.
Ivanova, T.
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Show full item recordAbstract
There is still a question of utilization of compost of unsatisfactory quality. This article
deals with energy utilization of untreated compost. The energy utilization of raw compost as a
fuel is not directly possible without further processing. Separation
might be necessary due to large
amount of mineral content (soils and other inert substances).
This article is focused on the analysis of the basic fuel characteristics of compost. Proximate and
elemental analyses were performed and stoichiometric combusti
on was calculated. Finally, the
sample was co
-
burned with wood biomass in a fixed grate combustion device and the gaseous
emissions were determined in dependence on the amount of combustion air supplied. The
emissions were expressed in graphs against exces
s air coefficient and flue gas temperature.
Elemental analysis of the compost sample shows high percentage of ash up to 61.70% wt. on dry
basis causing low average calorific value of 8.51
MJ
kg
-
1
on dry basis. For combustion tests, the
heating value was in
creased by addition of wood chips to reach an average calorific value of the
mixture to 13.4
MJ
kg
-
1
. The determined stoichiometric parameters can help in optimization of
diffusion controlled combustion of composts or similar materials. In combustion of th
e mixture
of compost and wood biomass an optimum of emission parameters was found not exceeding the
emission limits. Measured emission concentrations show the possibility of optimizing the
combustion processes and temperatures while lowering CO emissions v
ia the regulation of
combustion air.