Authors: Mariana Vale da Silva, Victor Ferreira, Aida Sanches, Carlos Pinho

This work presents the study of the thermal performance and combustion hygiene of a domestic briquette burning hot water boiler. The fuels tested were commercial briquettes, briquettes made from pine sawdust and vine pruning waste and eucalyptus logs. The thermal efficiency was determined by the direct method and it was found that the boiler thermal performance was quite similar for the different types of fuel tested and did not depend on the fuel feeding rate. The boiler efficiency values were in the 60.12 to 77.27% range. The dry basis molar composition of the boiler exhaust gases (O2, CO2, CO and NOx) was continuously monitored. In terms of the CO emissions, the worst situation was for the combustion of vine pruning waste briquettes, the fuel with the highest ash content, whereas as far as the NOx emissions were concerned the worst situation was for the combustion of commercial briquettes, which were those with the highest nitrogen content. Increasing the fuel mass flow rate lead to a decrease of the furnace excess air, which reflected in an increase of the exhaust gases temperature and a reduction of CO emission.

Mariana Vale da Silva¹| Victor Ferreira²| Aida Sanches²| Carlos Pinho³
1DEMEC – Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
2INEGI – Instituto de Ciência e Inovação em Engenharia Mecânica e Engenharia Industrial, Porto, Portugal
3CEFT – Faculdade de Engenharia da Universidade do Porto, Porto, Portugal