Patent GB-717192-A (GB)
Title: A vaporising system for a heavy liquid fuel, particularly for gas turbine power plant
Inventor: THOMAS ALUN
IPC: F23R3/32
Filed: 1952-04-17
Abstract: 717,192. Vapour burners. SHELL REFINING & MARKETING CO., Ltd. March 17, 1953, [April 17, 1952.] No. 9674/52. Class 75 (1). A vaporizing system for heavy liquid fuels, particularly for gas turbine plants, comprises means for supplying liquid fuel to the inner surface of a heat-conducting vaporizing tube wholly or mainly disposed within a combustion chamber, so as to be heated by the combustion products therein, means for continuously maintaining relative rotational and/or oscillatory movement between the vaporizing tube and scraper means for removing solid deposits from the inner surface thereof, an outlet for discharging vapour from said tube within the combustion chamber, and an outlet at one end of said tube for discharging solid material outside the combustion chamber. A vaporizing tube, 18, Fig. 2, which extends vertically across a gas turbine combustion chamber 12 is supplied with fuel via a pipe 44, a "banjo" fitting A, and a nozzle 41, or nozzles 41, 40a, which extends or extend through the wall of a rotary shaft 31 carrying a scraper 32 for cleaning the inner wall of the tube 18. The shaft 31 is coupled with a shaft 50 driven by a motor or other means. Vapour is discharged through a tube 57 leading to a burner nozzle (not shown), and is swept out of the vaporizer by streams of air and/or steam supplied at the upper and lower ends of the tube 18 through perforations 61, 62 communicating with air and/or steam feed pipes 63, 64 respectively. Fins 70 on the outer surface of the vaporizing tube 18 assist the transfer of heat thereto. A baffle 37 at the lower end of the shaft 31 shields the lower bearing 34 of the latter from solid material dislodged by the scraper 32, and diverts such material through apertures 38 in the bearing support to a discharge hopper 66 which can be closed at top and bottom by sliding or rotating valves 67, 68 operated manually or by driving mechanism. The upper end of the vaporizing tube is closed by a flanged plate 27 secured over an aperture in the wall 13 of an air jacket surrounding the combustion chamber 12, through which aperture the end of the vaporizing tube is allowed to expand on heating. In a modified construction the vapour outlet from the vaporizing tube is disposed between two inverted frusto-conical baffles through which the shaft passes, and two helical screws on the latter are located each in a flange depending from one of said baffles for conveying the scrapings to the discharge hopper. In this construction the carrier air and/or steam is passed through the vaporizing tube in an upward direction only. In a further construction the vaporizing tube 79, Fig. 6, is rotatable relatively to a fixed scraper 80, being secured to a rotary shaft 83 and the upper and lower ends being received in tubes 86, 89, respectively, secured to the wall 13. Liquid fuel is supplied through the shaft 91 carrying the scraper 80 to nozzles 96, 97 and 98, and the vapour is discharged through a pipe 99 leading to the burner nozzle. The scraper 80 is of channel form, having a semi-circular cross section, and the scrapings are passed through an inclined conduit 104 to a discharge hopper. Air or steam is passed into the vaporizing tube through a connection 102 and apertures 103 in the upper end closure of the tube and also through apertures 101 at the lower end. Alternatively the vapour is discharged from the vaporizer through an outlet in the wall of the tube 86 above an apertured upper end closure of the vaporizer, air or steam being supplied only at the lower end of the latter. A further construction is described in which the vaporizing tube rotates relatively to a fixed scraper, the vapour being withdrawn from the vaporizer at the upper end of a rotary tubular shaft which passes through and is secured to the vaporizing tube for rotating the latter. In this construction a number of vaporizing tubes may be arranged in a circle around the combustion chamber axis, each being provided with a burner nozzle. In a further arrangement, the air stream is divided between two combustion systems, one being fired by known means, and the other by vaporized fuel generated in a vaporizer heated by the first system, e.g. a bank of vaporizing tubes, one of which may supply fuel vapour to the first system.