Gasifier Control Unit for IGCC Plant Stabilization
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Solution Overview
Problem
Existing gasification power generation plants face challenges in stabilizing control due to variations in the heating value of synthesis gas, leading to increased fuel consumption and pressure deviations, which result in overshoots in oxidizer flow rates and require larger capacity equipment, causing inefficiencies and increased costs.
Innovation Solution
Implementing a control unit that switches between fixed-air-ratio and variable-air-ratio modes based on operating-state variations, allowing the oxidizer amount to deviate from set values within predetermined limits, thereby reducing overshooting and stabilizing the plant more quickly without increasing oxidizer supply equipment capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the air ratio is fixed to maintain stable operation, then the gasifier operates stably, but the plant takes longer to stabilize after load variations or heating value changes due to overshoot in oxidizer flow rate
Solution Approach 1:
The patent applies dynamics by switching the air ratio control from a fixed state to a variable state based on operating conditions. When load variation or heating value change is detected, the control unit changes the air ratio from a fixed set value to a variable value that adapts to the new conditions, allowing the system to respond dynamically and stabilize faster without excessive overshoot.
Solution Approach 2:
The patent changes the parameter of air ratio from a constant set value to a variable parameter that adjusts according to the gasifier's operating state. This parameter change enables the system to optimize performance under different conditions, reducing stabilization time while maintaining operational stability through controlled adaptation.
2Reliability
If the oxidizer supply equipment capacity is increased to handle overshoot, then the plant can handle load variations, but the equipment becomes oversized and less efficient during normal operation
Solution Approach 1:
The patent makes the air ratio dynamic rather than fixed, allowing the oxidizer supply system to operate at optimal capacity during normal conditions while adapting to handle load variations without requiring oversized equipment. The dynamic adjustment prevents the need for excessive capacity by intelligently modulating the air ratio response.
Solution Approach 2:
By changing the air ratio parameter based on operating conditions, the system optimizes the oxidizer supply equipment utilization. The parameter adjustment ensures the equipment operates efficiently during normal conditions while still having the capability to handle variations, eliminating the need for oversized design.
3Loss of time
If the air ratio is variable to respond to heating value changes, then the plant stabilizes faster, but the air ratio deviates from the optimal set value
Solution Approach 1:
The patent implements dynamic air ratio adjustment that balances response speed with control precision. The system transitions from a static set value to a dynamic adjustment mechanism that responds to heating value changes while incorporating control logic to minimize deviation from optimal operating conditions, achieving both fast stabilization and acceptable precision.
Solution Approach 2:
The air ratio parameter is changed from a fixed optimal value to a dynamically adjusted value that responds to heating value variations. This parameter change enables faster stabilization while the control system manages the deviation to maintain acceptable operational precision through intelligent adjustment rather than rigid fixation.
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 stabilizes the gasification power generation plant more rapidly, reduces the need for oversized oxidizer supply equipment, and minimizes deviations from optimal operating conditions, leading to improved efficiency and cost savings.
Implementation Method 1
a gasifier that gasifies carbon-containing fuel by using an oxidizer
Implementation Method 2
a gas turbine that is driven by combustion gas generated by combustion of fuel gas
Data Source
AI summary
An IGCC plant includes a coal gasifier that gasifies coal by using an oxidizer, a gas turbine that is driven by combustion gas generated by combustion of fuel gas obtained by purifying gas generated by the coal gasifier in gas clean-up equipment, and an oxidizer supply path for supplying air extracted from an air compressor of the gas turbine or oxygen separated from the air as an oxidizer for the coal gasifier. A control unit (50) for the gasification power generation plant controls the amount of the oxidizer that is supplied to the coal gasifier to be less than or equal to a predetermined upper-limit value, while allowing deviation of an air ratio from a predetermined set value, the air ratio representing the ratio of the amount of air that is supplied to the coal gasifier relative to a theoretical amount of air for combustion of carbon, in accordance with variations in an operating-state quantity of the coal gasifier or variations in a load of the IGCC plant. Accordingly, the capacity of the oxidizer supplying equipment need not be increased in the IGCC plant, and it is possible to quickly stabilize control of the plant as a whole.