Patent GB-888113-A (GB)
Title: Improvements relating to fuel combustion apparatus for heat exchangers
IPC: F22B33/08
Filed: 1957-06-25
Abstract: 888,113. Generating combustion products under pressure. FRAZER, R. P., and WOOSNAM, M. S. June 24, 1958 [June 25, 1957], No. 20052/57. Class 51 (1). [Also in Group XXVI] In combustion equipment associated with a heat-exchange device, such as a boiler, combustion of the fuel which is sulphur-bearing and may be liquid, gaseous or pulverulent, takes place in two stages, viz. an initial combustion stage in which less than the theoretically correct proportion of air or oxygen or oxygen-containing gases for complete combustion is supplied, and a second combustion stage in which the combustion gases produced in the initial combustion stage are completely burned by the addition of air or oxygen or oxygen-containing gases in such quantity that the ratio of fuel to total air or oxygen supplied is stoichiometric. The production of SO 3  from SO 2  gases is thereby avoided or minimized. In Fig. 1, an initial combustion chamber B is disposed within a casing C and air is supplied thereto through inlets C<SP>1</SP> entering the chamber B through the apertures shown. Fuel is supplied to the chamber by injector C<SP>2</SP> and is partly burned therein, the combustible gases produced discharging through duct B<SP>1</SP> into the second stage combustion chamber J to which air is supplied through ducts J<SP>2</SP>. The combustion products with no excess air discharge through coil ducts J<SP>1</SP> giving up heat. In a second embodiment, the combustible gases from the first combustion stage enter the second combustion stage and further fuel and air are supplied thereto, the ratio of total fuel to total air being stoichiometric. In Fig. 3, combustible gas is again produced in the first stage combustion chamber B, the gases discharging through outlet B<SP>1</SP> into the duct J<SP>3</SP> disposed within the heat-exchanger A. Further fuel is supplied into the space J<SP>5</SP> through injector R and further air is supplied through inlet J<SP>2</SP>, combustion of the combustible gases and additional fuel occurring in the space J<SP>5</SP> and in tubes J<SP>4</SP>. The resulting combustion gases then enter casing K and impinge on the turbine D, the exhaust gases discharging through tubes J<SP>6</SP> in the heatexchanger A and finally discharge to atmosphere through outlet J<SP>1</SP>. The turbine D drives an air compressor E which supplies air to casing C the air then entering the first combustion stage B. The fuel supply duct F is also driven by the turbine D, fuel being discharged through the rotary atomizer cup G. In Fig. 4, combustible gases produced in the initial combustion chamber B pass through duct J<SP>7</SP> disposed in the heat-exchanger A and then enter the casing K, discharging from there on to the turbine D, the gases discharging from there through duct O into the second stage combustion chamber J<SP>8</SP>. Further fuel is supplied to the chamber J<SP>8</SP> through injector R and air is supplied thereto from compressor E through duet H<SP>1</SP>. The combustion gases discharge through outlet J<SP>1</SP>. In a further embodiment similar to Fig. 4, air under pressure from the compressor E is admitted into the ducts such as O through small apertures therein, these ducts then serving as combustion chambers, the resulting combustion gases passing through ducts in the heat-exchanger A and thence to atmosphere. In this embodiment the fuel pump is driven by the turbine through the rotary shaft F. Specifications 825,124 and 827,719 are referred to.