Triple expansion waste heat recovery system and method

Abstract

A waste heat recovery system is provided. The waste heat recovery system includes a Rankine cycle system for circulating a working fluid. The Rankine cycle system includes at least one first waste heat recovery boiler configured to transfer heat from a heat source to the working fluid. The Rankine cycle system also includes a first expander configured to receive the heated working fluid from the at least one first waste heat recovery boiler. Further, the Rankine cycle system includes a second expander and a third expander coupled to at least one electric generator. The waste heat recovery system also includes a condenser configured to receive the working fluid at low pressure from the first expander, the second expander and the third expander for cooling and a pump connected to the condenser for receiving a cooled and condensed flow of the working fluid from the condenser.

Description

BACKGROUND[0001]The present application relates generally to power generation and, more particularly, to a system and method for recovering waste heat from a plurality of heat sources having different temperatures for the generation of electricity.[0002]Many industrial power requirements could benefit from power generation systems that provide electricity or mechanical power with minimum environmental impact and that may be readily integrated into existing power grids or rapidly sited as stand-alone units. Combustion engines such as gas turbines or large reciprocating engines are suitable for power generation in industrial applications but rely on increasingly costly fuel and also generate emissions and waste heat. One method to generate electricity from the waste heat of a combustion engine without increasing the output of emissions and without requiring additional fuel is to apply a bottoming cycle. Bottoming cycles use waste heat from a heat source, such as an engine, and convert...

AI Technical Summary

Benefits of technology

The invention is a waste heat recovery system that uses a Rankine cycle system to convert heat from a variety of sources into mechanical energy. The system includes multiple expanders and a pump to circulate the working fluid through the system. The system is designed to maximize the recovery of waste heat and generate power efficiently. The technical effects of the invention include improved energy conversion, reduced energy waste, and improved energy utilization.

Problems solved by technology

Combustion engines such as gas turbines or large reciprocating engines are suitable for power generation in industrial applications but rely on increasingly costly fuel and also generate emissions and waste heat.

However, the amount of heat that can be recovered from the waste heat source is limited as a boiler inlet temperature of the working fluid increases after passing the recuperator.

The boiler efficiency declines and the heat input as well as power output is limited.

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