GB378259A - Improvements in hot blast stove systems - Google Patents

Abstract

378,259. Hot blast stoves ; returning combustion products to furnaces. NAAMLOOZE VENNOOTSCHAP NIEUWE OCTROOI MAATSCHAPPIJ, 30, Carel van Bylandtlaan, The Hague.- (Assignees of Blanckenburg, E.; 136, Liberty Street, New York, U.S.A.) Oct. 16, 1931, No. 28824. Convention date, Oct. 17, 1930. [Classes 51(i) and 51 (ii).] In a hot blast stove system adapted to supply heated combustible gas for use in the cracking of oils, products of combustion from a stove which is being heated are passed through each stove at the end of the heating period to purge the stove of air. The stoves may also be purged of combustible gas at the end of the blast period and combustion products may be returned to reduce the temperature during the heating period. Each gas heating stove 10 is provided with a burner 13, a vertically extending combustion chamber 15 and checkerwork 17 communicating through a collecting flue 19 and duct 25 with the chimney 23. The waste gas ducts 25 of a set of stoves are connected by pipes 43 having valves 44 with a pipe 42 so that the waste gases may be withdrawn from any stove and forced by a fan 54 through pipes 45, 49 to the combustion chamber and burner of any stove through pipes 51, 52 respectively. Two stoves of a set of three are heated simultaneously and a proportion of the waste gases is returned for diluting the fuel gas supplied through pipe 41. When a stove has reached the proper temperature the gas and air are shut off and the stove purged of air by continuing the admission of flue gases from the pipe 49, the gases passing from the collecting flue 19 through a byepass pipe 57 and pipe 33 to the stack. The gas to be heated is then admitted through valve 56 from the cold gas main 55 and passed through ,the stove to a hot gas main and thence to the cracking system. When the temperature has dropped below the desired limit valve 56 is closed and flue gas again admitted to connection 51 and steam also admitted at 60, the chimney valve 21 being closed and the gases passing through the byepass 57 to the stack. The byepass 57 may communicate with a gas holder for storing the combustible gas displaced. When fuel of low calorific value is used in the burners 13 the amount of flue gas returned is reduced or the return for diluting purposes discontinued. Air supplied to the burners 13 is preheated in a recuperator 31; a valve 27 in the waste gas passage 25 determining the proportion of flue gas passed through the recuperator.