Experimental Studies on Wood Pellets Combustion in a Fixed Bed Combustor Using Taguchi Method

Abstract

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.

Improving Combustion Technology for Cooking Activities for Pollutant Emission Reduction and Carbon Neutrality

“…When crop straw was burned in pellet form, most of the air-pollutant emissions dropped by over 80% [29]. Similar results were discovered in woody materials [30,31]. In addition, pellets are convenient for storage and transport due to their significantly larger densities.…”

Combustion Instability and Ash Agglomeration in Wood Pellets Boiler

“…This research was conducted at the Laboratory of Energy and Fluids, School of Engineering, University of Minho, Portugal. As this is another part of the previous research conducted by the same authors [32]. The schematic diagram of the test facility used in this study is presented in Figure 1.…”

“…The computer unit, including a National Instrument data acquisition board, was used to monitor and control all the systems. The boiler condition can be seen in Castro et al [32]. In order to describe the combustion instability by emissions, the exhaust gases were also measured, including CO (13% of O 2 ), O 2 , and CO 2 in the chimney by a "Multi gas analyzer 9000" and NOx by a "NOx gas analyzer".…”

“…The ignition coil is in the front of the grate box and the fuel inlet is on the top of the grate. The grate applied in this study was of a rectangular shape that can be seen in the previous paper [32], can be easily changed and three different cross sections, areas according The total air flow rate is set by adjusting the ventilator draft and the primary/secondary air split is adjusted by throttling the primary air supply. The whole unit is covered by a jacket of rock wool to minimize the heat losses on the outside.…”

“…The ignition coil is in the front of the grate box and the fuel inlet is on the top of the grate. The grate applied in this study was of a rectangular shape that can be seen in the previous paper [32], can be easily changed and three different cross sections, areas according to the study were used. The grate model is schematically described in Figure 2, where 1 and 4 are primary and secondary air orifices (4 mm diameter) respectively, 2 is the primary air orifice on the bottom (3 mm width), 3 is the ignition hole and 5 is the secondary air inlet.…”