Performance Evaluation of Kiln for Cashew Nut Shell Carbonization and Liquid

Abstract

Cashew nut shell (CNS) was utilized for carbonization in developed prototype kiln. Prototype kiln was evalu- ated with direct and indirect methods and characteristics of CNS and CNS char were determined by proximate and ultimate analysis. The maximum CNS temperatures obtained inside the kiln during direct and indirect method were recorded as 452.2℃ and 458.8℃ respectively. Maximum oil percentage, charcoal percentage and ash percentage in direct method were observed as 21.1 per cent, 21.04 per cent and 3.34 per cent respectively whereas 23.8 per cent, 18.3 per cent and 1.27 per cent in indirect method respectively. Hydrogen content in CNS was found about 6 to 7 per cent and nitrogen content in CNS was found about 0.70 to 0.75 per cent. Oxygen content in CNS was observed about 29 to 31 percent. Carbon, hydrogen and nitrogen content of the CNS char were observed in the range of 73 to 76 per cent, 4 to 5 per cent and 1 to 2 per cent respec- tively. It was found that nitrogen content has increased in CNS char after the carbonization of CNS. Oxygen content in the CNS char gets reduced to 13 to 14 percent, which was comparatively very less than CNS. It was observed that indirect method is more suitable for carbonization than direct method for obtaining higher calorific value char and maximum fixed carbon percentage as found in cashew nut shell char as 60 per cent.