Intake air cooling method, intake air cooling device executing said method, and waste heat recovery facility and gas turbine plant each comprising said intake air cooling device
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Solution Overview
Problem
In gas turbine systems, existing intake air cooling methods lead to heat being transferred from the air to cooling water, causing the water to be heated and discharged, which results in inefficient heat utilization and potential boiling issues in waste heat recovery boilers, leading to pressure losses and water hammer phenomena.
Innovation Solution
An intake air cooling method and device that uses a heat pump to transfer heat from the air suctioned by the gas turbine to water, preheating it before sending it to a waste heat recovery boiler, while incorporating a supply water temperature adjuster and condensation return line to manage water temperature and prevent boiling, and optionally employing a second heat pump and low boiling point medium Rankine cycle for enhanced efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat is exchanged between intake air cooling medium and cooling water to cool the intake air, then the intake air can be cooled, but the cooling water is heated and discharged, resulting in inefficient heat utilization
Solution Approach 1:
The patent converts the harmful waste heat in cooling water into a beneficial resource by using it to preheat feedwater in the waste heat recovery boiler. The cooling water that would normally be discharged after cooling the intake air is instead routed through the feedwater heating system, where its thermal energy is utilized to raise the temperature of feedwater before it enters the evaporator, thereby eliminating waste heat loss and improving overall system efficiency.
Solution Approach 2:
The cooling water serves multiple functions: first, it cools the intake air in the heat exchanger; second, it preheats the feedwater in the waste heat recovery boiler; and third, it can be condensed in the condenser to generate additional power through the Rankine cycle. This multi-functional utilization maximizes the value extracted from the cooling water throughout the system.
2Loss of energy
If water is preheated excessively before entering the waste heat recovery boiler, then heat utilization efficiency improves, but water may boil in the economizer causing pressure loss and water hammer phenomena
Solution Approach 1:
The patent implements a feedback control mechanism where the temperature of preheated water is continuously monitored, and the flow rates of cooling water and feedwater are adjusted based on temperature differential feedback. When the temperature difference between cooling water and feedwater indicates risk of excessive preheating, the system automatically adjusts flow rates to maintain safe operating conditions, preventing boiler tube damage while maximizing heat recovery.
Solution Approach 2:
The system dynamically adjusts the flow rates of cooling water and feedwater based on real-time temperature conditions rather than operating at fixed rates. This dynamic control allows the system to optimize heat recovery efficiency under varying load conditions while maintaining safe operating margins that prevent water hammer and pressure loss issues in the economizer.
3Productivity
If mass flow rate of air suctioned by compressor increases, then output of gas turbine increases, but more heat needs to be removed from the air
Solution Approach 1:
The patent establishes a continuous heat recovery chain where heat is sequentially transferred from intake air to cooling water, then from cooling water to feedwater, and finally from feedwater to the Rankine cycle system. This continuous multi-stage heat recovery ensures that regardless of the air mass flow rate, all available thermal energy is captured and utilized, allowing the system to handle increased gas turbine output without proportionally increasing energy loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively cools the air suctioned by the gas turbine while preheating the water for waste heat recovery, suppressing boiling in the boiler and improving the overall efficiency and output of the waste heat recovery process.
Implementation Method 1
a heat pump device which transfers heat of air suctioned by the gas turbine to water flowing through the water supply line and thereby cools the air while heating the water
Implementation Method 2
a waste heat recovery boiler which converts the water into steam using heat of an exhaust gas exhausted from the gas turbine
Implementation Method 3
an intake air cooler which exchanges heat between the air and an intake air cooling medium and thereby cools the air while heating the intake air cooling medium
Implementation Method 4
an intermediate heat exchanger which exchanges heat between the intake air cooling medium heated by the intake air cooler and an intermediate medium and thereby cools the intake air cooling medium while heating the intermediate medium
Data Source
AI summary
An intake air cooling device includes a water supply line and a heat pump device. The water supply line is configured to send water to a waste heat recovery boiler which is configured to generate steam using heat of an exhaust gas from a gas turbine. The heat pump device is configured to transfer heat of air suctioned by the gas turbine to water flowing through the water supply line and thereby cool the air while heating the water.