GB972738A - Method and apparatus for drying and burning pipeline coal - Google Patents

Abstract

972,738. Drying coal; feeding pulverulent fuel. COMBUSTION ENGINEERING Inc. Sept. 20, 1962 [Dec. 15, 1961], No. 35825/62. Headings F4B and F4G. A slurry comprising crushed coal and water is partially dewatered, pulverized and carried by hot air to the burner of a boiler furnace. The slurry is fed from a storage tank 20 through a pump 22, control valve 24, flowmeter 26, shut-off valve 28 and into a hopper 30 from which it is gravity fed (or pumped) to a centrifuge 32. The centrifuge has a rapidly rotating cone frustum 34 surrounded by a partitioned casing 42 and a screw conveyer to force the partially dewatered slurry down the duct 44 to the pulverizing mill 50, whilst the expelled liquid which may contain 4-8% fine coal is mixed with a flocculating agent from the tank 72 and fed to a settling tank 76. The flocculated fines are fed to the hopper 30 and the clear water is fed to a tank 78. 'The pulverizing mill has a rotating bowl 52 co-operating with a spring roll 54 gas heated air being drawn, by means of the fan 56, through the mill from the duct 58 to dry and transport the coal through the duct 62 and the discharge duct 64 to the burner 66 in the furnace 68. The flowmeter measurement may be compared with the fuel quantity required for a certain condition of the furnace and any difference utilized for controlling the valve 24 and pump 22. An alternative dewatering device, a vacuum filter, is shown at Fig. 4 where perforated or mesh rotating hollow drums 102 have an internal vacuum maintained by the pump 104 and tip into the reservoir of slurry 106, the partially dry slurry being scraped by scrapers 108 on to a conveyer belt 110 for transportation to the pulverizing mill. Several centrifuge and pulverizer combinations may be connected in parallel to a common settling tank and storage tank, Fig. 3 (not shown).