Performance analysis of cross-draft biomass gasifier and synthesis gas burner as heat source for small ceramic kilns

The traditional biscuit firing process typically uses LPG, firewood, or electricity as a heat source. This research explores the application of a cross-draft biomass gasifier to generate and combust synthesis gas from rubberwood scraps as a heat source for small ceramic kilns. The firing program consists of two stages. In the first stage, rubberwood scraps are burned with primary air in the gasifier, causing the equivalence ratio (ER) to decrease from 2.07 to 1.36. During this stage, the kiln's internal temperature rises from room temperature to 400 °C. In the second stage, synthesis gas from the gasifier is burned at the burner with secondary air, reducing the ER from 1.68 to 1.18 and increasing the kiln temperature from 400 °C to 800 °C. Gas emission analysis showed that carbon monoxide (CO) remained below 690 ppm, while nitrogen oxides (NOx) peaked at 225 ppm at kiln temperatures above 400 °C. The final biscuit product exhibited a shrinkage of 2.69 %, a density of 1.71 g/mL, and a water absorption rate of 18.51 %.