IGCC Plant Steam Generator Integration for Heat Recovery
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Solution Overview
Problem
Gas turbine power generation plants using Integrated Gasification Combined Cycle (IGCC) suffer from low heat recovery efficiency and complex dual power extraction systems, leading to high investment and maintenance costs, as well as reduced efficiency due to indirect firing and steam turbine operation at lower temperatures.
Innovation Solution
The integration of Wet Cycle Turbine Technology with gasification, where steam generated from heat recovery is used to preheat and treat the fuel gas stream, reducing the need for excess air and enhancing combustion efficiency by transporting heat from the gasifier to the combustor, and incorporating a steam generator connected to the fuel gas treatment device to supply steam for indirect combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a steam generator is used to recover heat from flue gases in a traditional IGCC plant, then heat recovery is achieved, but the heat recovery efficiency is very low (only about 30% of heat captured from fuel gas stream)
Solution Approach 1:
The patent combines the steam generator function with the fuel gas treatment device into a single integrated unit. The steam generator is positioned to receive hot fuel gas directly from the gasifier and uses this heat to generate steam for fuel gas cooling and treatment, eliminating the need for separate heat recovery systems and achieving much higher heat recovery efficiency (about 10% improvement over traditional IGCC).
Solution Approach 2:
The steam generator performs preliminary cooling of the hot fuel gas stream before it enters the fuel gas treatment device. By pre-cooling the fuel gas and generating steam simultaneously, the system prepares the fuel gas for efficient treatment while maximizing heat recovery, avoiding the need for separate cooling and treatment systems.
2Loss of energy
If a dual power extraction system with steam turbine is used, then heat recovery is possible, but investment and maintenance costs are high
Solution Approach 1:
The patent merges the steam generation function with the fuel gas treatment device, creating a single integrated unit that performs both heat recovery and fuel gas cooling/treatment. This eliminates the need for separate steam turbines and complex dual power extraction systems, significantly reducing investment and maintenance costs while maintaining effective heat recovery capability.
Solution Approach 2:
The integrated steam generator/fuel gas treatment device performs multiple functions simultaneously: it recovers heat from fuel gas, generates steam for process use, cools the fuel gas stream, and prepares fuel gas for treatment. This multi-functionality replaces what would traditionally require multiple separate systems, reducing overall plant complexity and costs.
3Temperature
If indirect firing through heat exchangers is used in steam turbine cycles, then lower operating temperatures are required, but combustion efficiency is substantially reduced
Solution Approach 1:
The patent extracts the steam generation function from the traditional indirect firing heat exchanger system and integrates it directly into the fuel gas treatment pathway. This allows direct heat transfer from hot fuel gas to generate steam, eliminating the inefficiencies of indirect firing through complex heat exchangers while maintaining the benefits of controlled steam turbine operation.
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
This approach increases heat recovery efficiency by about 10% and allows for more stable combustion, reducing fuel costs and plant expenses, while also enabling the conversion of fuel gas into hydrogen with additional efficiency gains.
Implementation Method 1
heat in the flue gases downstream of the gas turbine is recovered by heat exchange in a steam generator
Implementation Method 2
a condenser positioned for water recovery in the flue gas stream
Implementation Method 3
steam generated from heat recovery is used to preheat and treat the fuel gas stream, reducing the need for excess air and enhancing combustion efficiency by transporting heat from the gasifier to the combustor
Implementation Method 4
The solid raw fuel is gasified following part combustion thereof for the production of a hot fuel gas stream
Data Source
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AI summary
A gas turbine power generation plant including: a solid fuel gasifier (5) for the production of a fuel gas stream, an arrangement for fuel gas treatment, a combustor (4) for receiving the fuel gas stream and for the production of a flue gas stream, a gas turbine unit (1) having an inlet for said flue gas stream and being mechanically coupled to an electric generator (2) for the extraction of useful work; a compressor unit (3) for the supply of compressed oxygen to the combustor (4). A steam generator (6) is arranged for heat recovery in the flue gas stream downstream of the turbine unit (1), a condenser (9) is positioned for water recovery in the flue gas stream, said condenser (9) having a connection for water supply to the steam generator (6), and the steam generator (6) is connected for supply of steam to the combustor (4) for contributing as process gas. The invention also concerns a method for operating a power plant and an arrangement and a method for fuel gas treatment.