GB639120A - Improvements in or relating to the supply of heat consuming operations - Google Patents

Abstract

639,120. Combustion processes ; coking and gasification processes. STANDARD OIL DEVELOPMENT CO. Aug. 6, 1946, No. 23325. [Classes 51 (i) and 55 (i)] A process for supplying heat to a heat consuming operation which comprises burning solid carbonaceous material in the presence of an oxidizing gas while in the form of a bed of fluidized solids having a relatively high carbon content to produce combustion gases containing substantial quantities of carbon monoxide, passing said combustion gases, together with at least sufficient oxygen to convert the carbon monoxide therein to carbon dioxide, through at least one bed of fluidized carbonaceous solids of relatively low carbon content under conditions to produce a final gaseous combustion product consisting substantially entirely of carbon dioxide, withdrawing hot solid residues from said beds of relatively high and low carbon content and utilizing at least part thereof to supply heat to said heat consuming operation. Fig. 1 (not shown), illustrates a heater suitable for carrying out the above dual combustion process and this heater is utilized in the system applied to the carbonization of coal and the generation of gas shown diagrammatically in Fig. 2. Fluidized coal fed from a hopper 1 is carbonized at 1,000-1,400‹ F. in a carbonizer 10 as a fluidized bed of material over a grid 9, the volatile carbonization products being led off by a pipe 18 after passing through a separator 15, and the fluidized coke produced is burnt in a heater 25 by the dual combustion process using a coke bed 30 of high carbon content and another 32 of low carbon content preheated air being supplied through the pipes 23, 24. Fluidized residues from the beds 30 and 32 pass by pipes 41 and 61 respectively to a carbonizer 10 and by pipes 42 and 62 to a gas generator 45 wherein passage of steam into the fluidized solids bed 43 kept at 1,600-1,800‹ F. produces water-gas which is vented off through the pipe 50, the residual solids being drawn off through a pipe 52 and recirculated to the heater 25 via a steam boiler 59 said solids being carried by flue gases introduced through a pipe 55. Control of the combustion in the heater 25 may be influenced by the addition of oxygen through a pipe 35, inert gases through a pipe 36, or by the recirculation of fluidized residues from the bed 32 through a boiler 66. In preparing the fuel bed 32 catalytic material containing iron oxide, high iron clays, red mud or spent cracking catalysts may be included. Oxygen may be supplied direct to the bed 32 of the heater 25 or under certain conditions, such as short contact times, sufficient oxygen to complete the conversion to carbon dixoide may be carried through the lower fluidized bed 30. Fig. 3 (not shown), illustrates a modification in which the directions of circulation of fluidized are modified and steam is used to convey the solids to the gas generator.