GB772072A - Improvements in or relating to the method of burning granular fuel - Google Patents

Abstract

772,072. Combustion apparatus. COMBUSTION ENGINEERING, Inc. April 20, 1955 [April 26, 1954], No. 11391/55. Class 51 (1). In order that a granular fuel of large particle size and low volatile content, e.g. char from low-temperature carbonization of coal utilizing the fluidized process or coke produced by the oil cracking processes which use fluidized coke beds, may be burnt in suspension it is simultaneously introduced into a furnace with a fuel which is capable of self-sustaining ignition such that a portion of it is burnt, the unburnt portion that passes from the furnace entrained in the combustion gases being collected and then pulverized such that it may be reintroduced into the furnace generally at the location of the burning fuel. In the furnace shown burners 16, 18, 20 project fuel and air in a tangential manner into a chamber 10 from which molten ash is continually drawn off through an opening 13 whilst the hot combustion gases, together. with entrained solids, pass via superheater 30, economizer 33, air heater 34, dust collector 28 to a chimney and hence into the atmosphere. Each of the burners is supplied with heated air from the air heater 34 through a duct 14 and together with this air burners 18 fire large particle sized, and low volatile content fuel whilst simultaneously burners 16 fire a gaseous fuel or other fuel capable of self-sustaining ignition with suspension firing. The unburnt fuel in the combustion gases is deposited partly in a hopper 36 and partly in a hopper 38 connected to the dust collector. The fuel so deposited is passed through pipe 40 to a pulverizing mill 42 which receives its carrier gas a mixture of air from the air heater and combustion gas from the chimney through ducting 41. The pulverized resultant entrained in the carrier gas is then passed to the burners 20 through ducting 44.