Suchergebnisse

The European Union aims to fulfill 20% of the primary energy consumption with renewable energy sources, by 2020. Biomass has a great potential for domestic and industrial heating applications and these are amongst the most promising uses for biomass as they combine high efficiency and ease of use. Pellets are a good method for biomass distribution due to its quality standards and energy density which make them attractive to distribution and handling. In addition to the traditional use of sawdust as a raw material, there has been a growing interest in the incorporation of residues from industry processing such as the furniture sector. This paper reports the application of pellets made of residues from the furniture industry as a fuel source in domestic heating applications. Pellets were characterized according to their chemical and physical composition. They were subsequently burned in an automatic boiler rated at 15 kW. A probe in the exhaust chimney was used to continuously analyze the flue gases. In addition, the ashes chemical composition was also analyzed. The results show that these pellets have a good thermal efficiency in domestic boilers, releasing however large emissions of NOx, originated from the high concentration of nitrogen in its chemical composition. The ash analysis confirms the slagging and fouling prediction, and these problems were verified in the grate, chamber combustion and heat exchanger. In conclusion, these pellets can be explored for industrial applications, with better control of its chemical composition. For domestic boilers however, these can cause serious ash problems. ; One of authors (P. T. Ferreira) acknowledges the scholarship (SFRH/BD/73101/2010) sponsored by ...

The combustion of wood pellets in a fixed bed combustor of a 20 kW capacity domestic pellet boiler was tested according to several factors including Power, Excess Air (EA), Primary/Secondary air Split Ratio (SR) and Grate Area (GA). The Taguchi method was applied to program the experimental design. Several parameters were measured, including gas emissions (CO), fuel bed temperature (measured at 4 different heights), and efficiency. The experimental results show that the lower CO emission and the higher efficiency were obtained at medium thermal loads and the highest temperature on the fuel bed was obtained at about ¼ of its height (15 mm). The results obtained from the analysis of variance (ANOVA) show that the SR and the Power are the most important factors contributing to the CO reduction and also increase the fuel bed temperature. ; This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units, MEtRICs Project Scope: UIDB/04077/2020; Lelis Fraga was supported through a PhD Grant by Fundo de Desenvolvimento Capital Humano of the Government of Timor ...