Power recovery and energy conversion systems and methods of using same

Abstract

In various illustrative examples, the system may include heat recovery heat exchangers, one or more turbines or expanders, a desuperheater heat exchanger, a condenser heat exchanger, a separator, an accumulator, and a liquid circulating pump, etc. In one example, a bypass desuperheater control valve may be employed. The system comprises a first heat exchanger adapted to receive a heating stream from a heat source after passing through a second heat exchanger and a second portion of a working fluid, wherein, the second portion of working fluid is converted to a hot liquid via heat transfer. An economizer heat exchanger that is adapted to receive a first portion of the working fluid and the hot discharge vapor from at least one turbine may also be provided. The first and second portions of the working fluid are recombined in a first flow mixer after passing through the economizer heat exchanger and first heat exchanger, respectively. A second heat exchanger is provided that receives the working fluid from the first flow mixer and a hot heating stream from a heat source and convert the working fluid to a hot vapor. The hot vapor from the second heat exchanger is supplied to at least one turbine after passing through a separator designed to insure no liquid enters the said at least one turbine or expander. The hot, high pressure vapor is expanded in the turbine to produce mechanical power on a shaft and is discharged as a hot, low pressure vapor.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention generally relates to heat recovery for the purpose of electrical or mechanical power generation. Specifically, the present invention is directed to various systems and methods for the conversion of heat of any quality into mechanical or electrical power. [0003] 2. Description of the Related Art [0004] In general, there is a constant drive to increase the operating efficiency of heat and power recovery systems. By increasing the efficiency of such systems, capital costs may be reduced, more power may be generated and there may be a reduction of possible adverse impacts on the environment, e.g., a reduction in the amount of waste heat that must ultimately be absorbed by the environment. In other industrial processes, an excess amount of heat may be generated as a byproduct of the process. In many cases, such waste heat is normally absorbed by the environment through the use of waste heat rejectio...

AI Technical Summary

Benefits of technology

[0015] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an exhaustive overview of the invention. It is not intended to id

Problems solved by technology

This process is complex and requires either multiple steam turbines or a multistage steam turbine, feed water heaters, steam drums, pumps, etc.

The system remains complex and is highly inefficient at low operating temperature differences.

The four largest weaknesses of the prior art system are a) the vapor 107 discharged from the second turbine 124 is significantly superheated and thereby the system of FIG. 5 fails to recover a portion of the valuable heat, b) the system utilizes a subcritical working fluid which limits the efficiency of the heat recovery in the heat recovery heat exchangers 120 and 121 due to the non-linearity of the temperature-enthalpy profile in said exchangers, c) the system generates unnecessary entropy further reducing its output in accordance with the Second Law of Thermodynamics, and d) the complexity of the system having multiple turbines and multiple heat recovery heat exchangers is reflected in an increased cost of the system for a given capacity recovery heat exchanger(s) are usually the largest costs in a system of the type.

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