Author(s): Geon-woo Ha, Ji-yeon Sim and Hye-rin Pyo

Abstract: Nearly 1.3 billion tonnes of agricultural residue are generated worldwide each year, yet only a fraction is converted into useful thermal energy through decentralised gasification systems ^[1]. This research presents the design, fabrication and thermal testing of a low-cost porous-media burner (PMB) intended to combust producer gas from a small downdraft gasifier fuelled with rice-husk briquettes. The burner body was constructed from a 100 mm diameter stainless-steel cylinder packed with two layers of alumina-based porous media: a fine upstream pre-heat zone (3 mm pellets) and a coarser downstream combustion zone (10 mm saddles). Producer gas was generated on-site and its volumetric composition, determined by micro gas chromatography, averaged 18.7% CO, 14.3% H?, 3.2% CH?, 12.8% CO? and 48.6% N? with minor traces. The burner was operated at equivalence ratios (?) from 0.6 to 1.0 while axial temperature profiles, flue-gas emissions and thermal efficiency were recorded. Peak bed temperature reached 953 °C at ? = 1.0 at the mid-bed station (x = 100 mm), decreasing to 412 °C at the inlet under the leanest mixture. CO and NO? emissions stayed below 48 ppm and 31 ppm respectively across all tested ratios, satisfying the South Korean indoor-combustion guideline. Thermal efficiency, defined as the ratio of useful heat absorbed by a water-cooled calorimeter to the chemical energy of the producer-gas feed, ranged from 61.3% at ? = 0.6 to 78.9% at ? = 0.9. A simple cost analysis placed the total material expenditure at approximately USD 127, making the unit accessible for small-holder farming operations. The data show that a two-layer alumina porous bed can sustain stable, low-emission combustion of low-calorific-value producer gas across a wide equivalence-ratio window, and the accompanying cost figures confirm its suitability for resource-limited settings.

DOI: https://www.doi.org/10.22271/27078043.2026.v7.i2a.138

Pages: 56-60 | Views: 86 | Downloads: 43

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