Improvement in Recuperative Gas Cycles by Means of a Heat Generator Partly By-Passing the Recuperator: Application to Open and Closed Cycles and to Various Kinds of Energy

Abstract

A particular arrangement applicable to open or closed recuperative gas cycles, consisting of a heat generator partly by-passing the low pressure side of the recuperator, is proven to enhance the advantages of gas cycles for energy production. In this way, the cogeneration of both power with high efficiency owing to the recuperator and high temperature process heat becomes possible and economically attractive. Furthermore, additional possibilities appear for power generation by combined gas and steam or ammonia cycles. In any case, the overall utilitization coefficient of the primary energy is increased and the combined production of low or medium temperature heat can also be improved. The great operation flexibility of the system for combined energy generation is worth being emphasized: the by-pass arrangement involves no significant change in the operating conditions of the main turbocompressor as the heat output varies. Applications of this arrangement are made to open and closed gas cycle power plants using fossil, nuclear and solar energies. The overall heat conversion efficiency is tentatively estimated in order to appreciate the energy conversion capability of the investigated power plants.

Power Generation From a 770°C Heat Source by Means of a Main Steam Cycle, a Topping Closed Gas Cycle and an Ammonia Bottoming Cycle

“…The relatively small topping gas turbine cycle would play a prominent part in this field for the following reasons : -its waste heat is easily available on an extended range of temperature ; -it is a closed cycle,and its load can be changed quite easily, without conversion efficiency penalty, by varying the working gas inventory, i.e. the mean pressure of the circuit ; a further improvement in increasing process heat conditions, performances and operational flexibility can be offered by a recuperator by-pass arrangement as described in (12), (13), (14), and summarily shown in Fig. 8.…”

“…main cycle bypasses, can be used ; the recovery of the waste heat is effected over a significant temperature variation range and without a phase change of fluids ; -another attractive possibility which would be very useful in the case of a change in the heat sink temperature involving a modification of the compressor inlet temperature, consists in using the so-called bypass arrangement on the LP side of the recuperator. Details about this adjustment of recuperative gas cycles can be found in (12), (13), (14), (16). A limited LP gas flow by-pass, effected from an intermediate temperature of the recuperator LP side, as shown in Fig.…”