Effect of Hot Briquetting Conditions on Briquettability of Preheated Fine Coals

Abstract

A double-roll briquetting machine was selected to conduct hot briquetting of the preheated fine coal without binder. Since a scale-up theory for the briquetting machine has not been established, its diameter was set at 1200 mm as the same size as that of commercial scale machine.
We were obtained as following findings about the effects of hot briquetting conditions on briquettability.
(1) The relation between the residence time of coal in a hopper and gas pressure in a void of packed bed was clarified. Enough residence time is effective means to prevent increase of gas pressure during hot briquetting of the preheated fine coal.
(2) When the briquetting temperature is more than 360°C, gas pressure in a void of packed bed rises rapidly over 5 kPa and the yield of briquette is decreased. In order to control gas pressure in a packed bed to 5 kPa or less, it is necessary to control the briquetting temperature 360°C or less.