Small heat source used for combustion of wheat-straw pellets

Abstract

Wheat straw, as a secondary waste agricultural product, presents a potential renewable source of energy. It is necessary to design simple heat sources to achieve better usage. As part of an analysis of heat sources, a tubular type of heat exchanger was reviewed. The design of the exchanger was focused on the smallest possible dimensional requirements, low costs, high reliability and easy maintenance. We chose a tubular type of heat exchanger. In our case, flue gas flows through the tubes, and water flows outside of the tubes. This type of exchanger allows for continuous cleaning, but also simple maintenance, even in case of equipment failure. It is possible to replace individual parts (pipes) of equipment that are exposed to the adverse corrosive effects of biomass flue gases. A mathematical model was composed to compute the construction of a heat source. The model was verified by CFD simulation. The main idea of this design is modularity. The composed model can be used to design a series of similar heat sources with different levels of power, and which, as it is of maximal availability for this type of construction, increase use of waste straw as fuel by small farms.