INDIRECTLY AIR-COOLED CONDENSING SYSTEM

摘要

1307996 Condensation of steam; cooling water for jet condensers GEA LUFTKUHLERGESELLSCHAFT HAPPEL GmbH & CO KG 17 March 1970 [17 March 19691 12720/70 Heading B1B Steam discharged from turbine 1 is condensed by contact with jets of cool water from nozzles 5a in condenser 5, the mixture of condensate and cooling water leaving the condenser divides into two streams, one of which is conveyed by pump 7 to the boiler (not shown), the other stream is cooled by pumping it via manifold 10 through groups of elements 12 (e.g. finned tubes) exposed to atmospheric air, and the cooled water collected in manifold 15 is passed to the nozzles of the condenser 5 via pipe 16 and valve 17. The pressure within condenser 5 is maintained as low as possible, e.g. 0.15 atm. abs. by air ejector 27. The highest points of the elements 12 are connected by pipes 35, 35a to the air ejector 37 of the condenser; but the elements 12 can also be maintained under reduced pressure by connecting their highest points to the condenser itself (Fig. 3, not shown) or to a separate vacuum pump (Fig. 4, not shown). In the system shown in Fig. 4, two of the elements 12 have water-level gauges which start the vacuum pump whenever the water-level falls below a given minimum due to a corresponding rise in pressure in pipe 35 owing to access of atmospheric air or release of inert gases from the water. The pump remains in operation until the air or inert gases have been ejected from elements 12 and the water has risen to its normal level. Alternatively the pump may be allowed to run continuously. Each group of elements 12 is fitted with a temperature gauge and this, together with a pressure gauge in pipe 35, sends signals to a regulator which adjusts valve 17 so that the pressure in pipe 35 does not fall below the saturation pressure in the upper ends of elements 12. The systems shown in Figs. 2 and 4 are provided with a supply of protective gas, such as nitrogen, connected to pipe 35, and this permits the elements 12 to be filled with protective gas when they are drained. In the system shown in Fig. 5, the highest points of elements 12 are connected to the ejector pump of the jet condenser (as in Figs. 1 and 2), but a separator, which removes water that may have entered the main vacuum system, is connected between pipe 35a and the ejector pump. The separated water is returned to the cooling cycle. The pressure-reducing valve 17 may be replaced by an expansion turbine.