GB1056722A - Improvements in or relating to power-generating steam cycle - Google Patents

Abstract

1,056,722. Turbine power plant. A. M. SQUIRES. Jan. 15, 1965 [Jan. 15, 1964; July 2, 1964], No. 2016/65. Headings F1G, F1Q and F1T. Steam generated at 22 in a turbine plant is superheated at 23 before passing to a combustion chamber 1 where additional heat is added by the combustion of a "clean fluid fuel" F, such as natural gas or alcohol, with oxygen or a gas containing oxygen as its primary component. The term "clean fluid fuel" means fuel substantially free of sulphur, ash substances and particulate matter and preferably rich in hydrogen. The mixture of steam and combustion products leaving chamber 1 expands in the first turbine stage 2 and is reheated by the addition of the products of combustion of further clean fuel and oxygen in combustion chamber 3. Further heat is added in combustion chambers 5, 7 intermediate turbine stages 4, 6, 8. The mixture of steam and combustion gases leaving stage 8 is cooled by boiler feed water in heat exchanger 9 before expanding to sub-atmospheric pressure in turbine stage 10. A major portion of the exhaust from stage 10 is condensed in condenser 12, a vacuum pump 13 drawing off non-condensible gases and steam vapour. The steam vapour is condensed at 14 and 16 and carbon dioxide discharged to atmosphere. Excess condensate from 12, 14, 16 is also discharged. The pressure of the feed water is raised by pumps 18, 19 and heat added at 20 without boiling. Steam is raised by further heat addition at 22 and in heat exchanger 9. Steam bled from turbine stage 10 may also heat the feed water. In a modification, Fig. 2 (not shown), stage 10 and condenser 12 are replaced by a closed power cycle having a turbine 42 and a working fluid such as ammonia, sulphur dioxide or a wide range of freons, e.g. trichloromonofluoromethane. In this plant superheated steam from 23 is admitted to a combustion chamber 31 together with clean fuel F. Oxygen is supplied to chamber 31 in an amount insufficient for complete combustion of the fuel such that a mixture of steam, carbon dioxide, hydrogen and carbon monoxide leaves the chamber to enter turbine 32. The turbine has a series of internal nozzles 33a, 33b, 33c, situated between rows of blades for admission of small quantities of oxygen to complete combustion of the fuel F and effect reheating of the steam/combustion product mixture. The mixture on leaving turbine 32 is cooled in heat exchanger 9, as before, and then passes to a heat exchanger 34 where the closed cycle fluid is heated, condensation water being collected in drum 35. An additional heat exchanger upstream of exchanger 9 may also effect cooling of the mixture in preheating the oxygen and fuel F. Further heating of the closed cycle fluid occurs in heat exchangers 36, 38, condensation water being collected in associated drums 37, 39 respectively. Uncondensed gas is vented from drum 39. Heat is also added to the closed cycle at 45 and 46, condensation of vapour from turbine 42 occurring in a condenser 43. In both embodiments the sources of heat Q, to Q6 may be, for example, turbine exhaust gases, heat from a turbine blade cooling arrangement, or waste heat from a chemical process. Other sources of heat are specified.