Chemical Recovery Boiler Char Bed Temperature Control
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Solution Overview
Problem
Chemical recovery boilers face issues with uneven smelt flow, leading to jellyroll smelt formation, which causes explosions and erosion of smelt spouts, and problems with injection gun clogging and boiler water leakage, which affect operational efficiency and safety.
Innovation Solution
The use of cameras and optical detectors to image the char bed and measure temperature profiles, allowing for real-time control of the boiler to maintain optimal smelt temperatures and detect issues such as clogging or leakage by determining local temperature deviations from thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If excess primary combustion air is supplied to increase furnace temperature, then jellyroll smelt formation is reduced, but carryover formation increases
Solution Approach 1:
The combustion air supply is divided into multiple zones: primary air at the bottom, secondary air in the middle, and tertiary air at the top. This segmentation allows targeted temperature control - excess air can be supplied locally near the smelt spout to prevent jellyroll smelt without excessively increasing overall furnace temperature that would cause carryover
Solution Approach 2:
Different air supply conditions are applied to different locations within the furnace. Local quality control enables specific regions (near smelt spouts) to have higher air supply for temperature control, while other regions maintain optimal combustion conditions, preventing both jellyroll smelt and excessive carryover
2Measurement precision
If camera systems and optical detectors are installed to monitor temperature profiles, then operational safety and control precision are improved, but device complexity increases
Solution Approach 1:
A camera system acts as an intermediary to non-invasively measure temperature profiles through the furnace wall. This optical measurement approach provides precise temperature data without requiring physical sensors inside the harsh furnace environment, maintaining measurement precision while avoiding the complexity of installing and maintaining intrusive measurement devices
Solution Approach 2:
Mechanical contact-based temperature measurement (thermocouples, resistance thermometers) is replaced with optical measurement using cameras. This substitution eliminates the need for physical sensor installation in the furnace, reducing device complexity and maintenance requirements while maintaining or improving measurement precision
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 minimizes jellyroll smelt formation, extends the life of smelt spouts, and prevents costly maintenance by promptly addressing temperature-related issues and potential leaks, thereby enhancing operational safety and efficiency.
Implementation Method 1
imaging an area (A) of a char bed (150) of the chemical recovery boiler (100) using at least a first optical detector (410) and a second optical detector (420) to obtain a two-dimensional or a three-dimensional spatial temperature profile
Data Source
AI summary
A method for controlling a chemical recovery boiler. The method includes measuring concentrations of sodium carbonate, sodium sulfide, and sodium sulfate from green liquor of the chemical recovery boiler, determining a target temperature for smelt, imaging at least an area of a char bed of the chemical recovery boiler, the area being close to a smelt spout, to obtain an image of the area, determining a measured temperature of the char bed using the image of the area. The method further includes determining that the measured temperature of the char bed is less than the target temperature for smelt, and controlling the chemical recovery boiler such that the temperature of the char bed increases. A chemical recovery boiler for the same.