GB781825A - An improved method of and apparatus for burning a low ash content particle-form fuel - Google Patents

Abstract

781,825. Pulverized fuel-fired combustion apparatus. BABCOCK & WILCOX, Ltd. Sept. 1, 1955 [Sept. 7, 1954], No. 25116/55. Class 51 (1). A particle-form fuel of low ash content is burnt in a cyclone furnace in the presence of air and a slag-forming material. The latter may be a high volatile pulverized coal but if of a non-combustible refractory nature then a supplementary fuel, such as oil, gas or pulverized coal, may require introduction into the furnace. In the furnace shown for burning " petroleum coke " such material is fed nearly tangentially carrier air borne via a series of ports 33 into the combustion chamber 12 immediately behind, in the direction of gas whirl, the secondary air flow tangentially introduced through a damper 32 controlled slot 31. The " coke " drops from hopper 34, feeder 35 and rotary seal 36 into the carrier air flowing through the duct 40. The slag-forming material is either a low-temperature clay or sand or lime or any other non-combustible refractory and is passed to the furnace from a hopper 50 through a feeder 51, rotary seal 52 and a duct 28 in which a carrier airstream flows. In order to minimize the use of new material, slag from the furnace is recovered from a quenching pit 26 in a granulated condition and fed to the hopper 50 through a pneumatic conveyer 48. An oil burner 27 is provided, the necessary primary air entering through the duct 28 whilst tertiary air enters in controlled quantities through a duct 30. A whirl motion is imparted to the air and entrained solids from the duct 28 in a furnace inlet section 16. The slag-forming material may be a high-volatile bituminous coal supplied with primary air and, if desired, granulated slag from hopper 50, through duct 28 and section 16. In such a case the burner 27 may be omitted. If a gaseous supplementary fuel is used then the latter is preferably introduced through burners positioned in the air slot 31. Specification 552,747 is referred to.