Biomass Boiler Flame Loss Control via Fan Speed and Baghouse Bypass
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Solution Overview
Problem
In combined gasifier-boiler systems, particularly those using biomass fuel, there is a lack of safety features to prevent unburned gas accumulation in the boiler exhaust system, which can lead to hazardous conditions such as fires in the baghouse due to unstable conditions in the gasifier.
Innovation Solution
A control system and method that includes a measurement device to detect loss of flame in the boiler, automatically bypassing the baghouse and reducing the speed of the induced draft fan to reduce hazardous conditions and attempt to reignite the flame, while ensuring the baghouse is bypassed to prevent fires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If safety features like flame detection are implemented in the boiler, then safety against fire hazards is improved, but device complexity increases
Solution Approach 1:
The system uses the existing induced draft fan to automatically perform the safety function by reducing its speed when flame loss is detected, eliminating the need for separate active safety components. The fan's inherent capability is leveraged to both maintain normal operation and respond to safety conditions.
Solution Approach 2:
The induced draft fan serves dual functions: it normally draws exhaust gases from the baghouse for output, and it automatically reduces speed to prevent fire hazards when flame loss is detected. This multi-functionality eliminates the need for dedicated safety devices.
2Reliability
If the baghouse is bypassed during flame loss, then safety against fire hazards is improved, but productivity decreases due to reduced exhaust gas processing
Solution Approach 1:
The system dynamically adjusts the baghouse bypass valve position based on flame detection status. During normal operation, the baghouse processes exhaust gases fully. When flame loss is detected, the valve automatically opens to bypass the baghouse, and closes when flame is restored, providing dynamic adaptation to operating conditions.
Solution Approach 2:
The system takes preliminary action by reducing the induced draft fan speed before the baghouse bypass is fully activated, creating a gradual transition that minimizes productivity impact while still preventing fire hazards.
3Reliability
If the induced draft fan speed is reduced during flame loss, then safety against fire hazards is improved, but energy consumption increases
Solution Approach 1:
The system changes the operating parameter (fan speed) in response to detected flame loss conditions. The fan speed is reduced from its normal operating level to a lower level that prevents fire hazards while consuming less energy than full-speed operation would require.
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
The solution effectively reduces and eliminates hazardous conditions by automatically addressing a loss of flame in the boiler, attempting to relight the burner, and ensuring the baghouse is bypassed to prevent fires, thereby enhancing safety and system stability.
Implementation Method 1
A measurement device associated with the boiler is configured to measure a temperature of the flame of the boiler and to determine loss of flame based on the temperature
Implementation Method 2
the induced draft fan is configured to control the production rate of energy and to run at a predetermined speed to draw filtered exhaust gas from the baghouse for output via an exhaust system
Implementation Method 3
The baghouse is configured to receive exhaust gas from at least the boiler to remove particulates therefrom
Implementation Method 4
The boiler has a flame for igniting the exhaust gas received from the gasifier and for providing power
Data Source
AI summary
A system and a method for controlling operation of a power plant system. The system has at least a gasifier, a boiler, an induced draft fan, and a baghouse. A controller in communication with the system is configured to implement a first stage and/or a second stage sequences after detecting loss of flame in the boiler using a temperature measurement device. The method includes automatically bypassing the baghouse and controlled (e.g., decreasing) the speed of the induced draft fan in the system to relight the boiler. The input feed to the gasifier can be limited and devices operated for a predetermined amount of time before reigniting the boiler.