Coal Briquetting lines was introduced by CASE to take care of the coal fines generated when processed in the Gasifier. By this technology the coal fines can be used upto 30% with the coal in the Gasifier thus making the gasifier process more economically efficient.
The briquetting machine works on the principle of Green Pellet process. The main process line consists of :
The sizes can be controlled in the Pulveriser , which is mainly kept below 1mm. Fines of coal are manually loaded on the belt conveyors and are made to enter the pulverizing zone. Before the coal fines reach the Pulveriser, binding media is added into the coal fines with the help of a hopper having a Rotary Air Valve arrangement. This RAV ensures the exact quantity required for the efficient binding of the briquette. The mixture of coal and binder is made to enter the pulverizing zone where is it undergoes sizing and first level mixing.
After the Pulveriser the mixture of coal fines and binder is made to enter the mixing zone where water is added and all three ingredients mainly coal fines, binder and water are thoroughly mixed. Normal water at 15% by volume is added to the mixer (The amount of water depends upon site conditions, quality of coal and the binder conditions). The consistency is checked by taking a handful of the wet mix and pressed in the hand. The mix should not stick on the hand but should stay as a lump with little amount of loose mix sticking to the hand.
The mix is then conveyed to the briquetting machine where the cavities compact the mixture dust to briquette. The briquette should only be used after a drying period for 48 hours.
The Pulveriser consists of a container, in which a shaft with paddles is mounted, in a fashion that it pulverizes the coal to the required size. A 22 kW three-phase motor drives the machine and the drive is through a pulley and belt arrangement.
The mixer consists of the shaft in opposite direction has paddles mounted at an angle to thoroughly mix the coal dust and the binder in the presence of water.
The machine consists of two rollers with ovoid cavities. The mixed material is loaded in the hopper goes through the compaction between these rollers to ovoid shape. The degree of compaction can be adjusted by moving one of the rollers towards other. However, we recommend to keep at least 1 mm gap between the rollers. The pressure is enough to compact the dust to the requirement for our gasifier.