ES279532A1 - Furnace wall arrangement - Google Patents

Abstract

A forced-flow, once-through vapour generator, particularly one operating at supercritical pressure, has furnace lining tubes which extend vertically in parallel relationship between inlet and outlet headers 54, 60 and 58, adjacent tubes being connected together over the height of the combustion chamber 10 by welding or as shown (Fig. 5) by elements 86 to which the tubes are welded. A vertical panel of similarly connected tubes 29 forms a partition in the combustion chamber, the tubes 29 extending in parallel between inlet and outlet headers 40, 42. At full load, when the generator operates as a once-through, forced-flow system, the working medium flows serially through an economizer 32 in a rear gas pass 14, the partition tubes 29, rear gas pass wall-lining tubes 47 which may be interconnected as shown in Fig. 5 and then to the wall-lining tubes of the combustion chamber. From the outlet header 58 into which the latter tubes discharge, the working medium flows through superheating surfaces 70, 80 before flowing to a turbine 82. A reheating stage 84 is disposed in a lateral gas pass 12. At part load a recirculating pump 90 draws part of the working medium from the header 58 and delivers it into a mixing vessel 36 for recirculation through the heating surfaces together with the through-flow also delivered to the mixing vessel 36 by a feed pump 30. Recirculation of the working medium serves to prevent temperature unbalance and stresses in the wall panels which might lead ultimately to fatigue failure. The four walls of the combustion chamber are welded together or to connecting elements at the four corners to form a gas-tight easing which may be suspended by hangers 93 at the upper end. In modification, Fig. 1 (not shown), the outlet header for the tubes forming a partition in the combustion chamber is connected directly to the inlet headers for the wall lining tubes.