GB688422A - Improvements in or relating to pebble heating and apparatus therefor - Google Patents

Abstract

688,422. Pebble-heating apparatus. PHILLIPS PETROLEUM CO. Nov. 1, 1950, No. 26666/50. Classes 64 (i) and 64 (ii) A pebble-heating chamber is provided with a moving bed of pebbles supported by a single selfsupporting refractory dome dividing the chamber into a heating zone above the dome and a combustion-gas zone below the dome, the pebble outlet from the chamber extending centrally through the dome and downwardly through the combustion zone. In the form shown in Fig. 1, the pebble-heating chamber comprises a shell 11 lined with common refractory material 14 such as fire brick with an inner lining 15 of super refractory material such as silicon carbide. The pebbles, formed of solid refractory material such as silicon carbide, alumina, periclase, beryllia, stellite, zinconia or mullite, are in the form of a fluent bed 28 moving between an inlet 29 and an outlet 23. The pebble bed is supported by a perforated dome 16 of super refractory material formed into tapered bricks 17, Fig. 2, arranged in ring formation. Grooves at the sides of the assembled bricks form holes for the passage of hot gases from a combustion chamber below the dome fitted with tangential gas burners 25. Methane-rich gas with oxygen may be used. To ensure the passage of hot gas upwardly through the centre of the pebble bed, a baffle 26 is provided. The lower part of the bed is formed of aggregate 27 or a refractory cone may replace the aggregate. The pebble outlet comprises an upper super refractory throat part 18 formed in sections and a lower part 23 formed of refractory rings 24 with an expansion joint between the parts. Fig. 5 shows the use of the heater 11 in conjunction with a lower pebble flow chamber 35 for heating gas which enters at 36 and leaves at 37, the pebbles being raised by elevator 38 from the outlet of chamber 35 to the inlet of chamber 11. To prevent the passage of combustion gases from one chamber to the other, hot inert gas may be forced into the pebble outlet conduit. Specification 688,421 is referred to.