Turbogenerator Options for a Heat-Recovery Thermal Power Complex on the Basis of a Low-Boiling Working Fluid

Abstract

Optional lists of turbogenerator equipment for a 1-MW heat-recovery thermal power complex operating on isopentane are examined. It has been found that, with the selected initial conditions, the axial turbine used as a direct drive of the generator with a standard speed of 3000 rpm should have five or six stages with the first stage having a partial admission of the working fluid. An alternative 6500 rpm, high-speed five-stage turbine for driving a generator with subsequent conversion of the current frequency has approximately halved the diametrical overall dimensions and the increased internal efficiency due to the elimination of the partial admission of isopentane vapor, reduction of the losses caused by clearance leakages and disc friction, yielding a total of at least than 3%. Should a 8400 rpm high-speed turbine be used, the number of stages may be reduced to three. High-speed turbines are less labor intensive to manufacture. The turbine generator can be made suitable for using heat sources different in power and temperature potential by modifying the basic design of the turbine through adding or removing the first or the last stages. A prototype of a heat-recovery power complex can be created using commercial equipment, conventional technologies, and standards adopted for the manufacture of high-pressure cylinders (HPC) of steam turbines. At the same time, a turbine generator with commercial prospects should be a high-speed unit integrated into a closed loop featuring minimal manufacturing and operating costs using equipment specially designed for this service.