GB948410A - Method and system for generating steam - Google Patents

Abstract

948,410. Direct contact steam boilers. COMBUSTION ENGINEERING Inc. Oct. 26, 1961 [Nov. 21, 1960], No. 38340/61. Heading F4A. A method of generating steam at subcritical or supercritical pressures involves introducing feedwater into a circulating stream of steam at a point where the steam is superheated, thereby evaporating the feedwater to produce a combined stream of steam which is at least at saturation temperature. A quantity of this steam, generally corresponding to the amount of feedwater introduced is withdrawn and superheated and conveyed to the point of use, the remaining circulating steam being compressed and resuperheated and the cycle repeated. Steam circulates in the system denoted by numeral 16, being compressed by a compressor 18 and superheated in parallelconnected tubes 20 of which there may be a large number and which are disposed in fire chamber 10. Feedwater supplied by pump 66 is preheated at 30 and is introduced into the stream of steam by temperature controlled spray means 34 and 36 at locations in tubes 20 such that at least some of the water is introduced after the steam has traversed the full length of superheater tubes 20. Steam is withdrawn at point 38, the remaining circulating steam passing to the compressor inlet to repeat the cycle. The withdrawn steam is superheated in low, intermediate and high temperature portions 40, 42 and 44 respectively of a superheater unit also disposed in chamber 10, and passes to the point of use which as shown comprises turbines 48 and 54 having an interstage reheater 52. Final temperature control of the steam passing to the turbines is provided by spray-type desuperheaters 50 and 58 respectively.