An Experimental Study of Spontaneous Ignition of Rice Husks

Abstract

Spontaneous ignition of rice husks is one of the risk factors for fires. The objectives of this study were to analyze the spontaneous ignition of rice husks by comparing the ratio of the chemical energy release from combustion to heat loss due to the conduction of rice husks, and to assess the safe storage size of rice husks that did not cause spontaneous ignition using Frank-Kamenetskii theory. Experiments were done by collecting rice husks samples into cube shaped containers with 8, 9 and 10 cm side lengths. Each sample was heated to the target temperature in a convective oven. From the calculation, (E/) was 8850 K and (Ahc/k) was 6.58 x 10¹² K/m². Then, the calculated Damkohler number was used as a guideline to determine the safe storage size of rice husks in the shape of a cylinder and a rectangle under the rice husks storage condition in a certain mill where the highest temperature was 39.9°C.