Cooled Smelt Restrictor Assembly for Recovery Boiler Flow Control
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Solution Overview
Problem
The existing methods for controlling smelt flow from a recovery boiler to a dissolving tank are inadequate in managing abnormal or heavy smelt flows, leading to explosions and equipment damage due to the large temperature differential between the hot smelt and cooler liquids, which conventional shatter jet nozzles cannot effectively mitigate during upset conditions.
Innovation Solution
A smelt restrictor assembly with a rotatable restrictor plate and actuator is introduced, allowing for remote control of smelt flow blockage, coupled with a cooling mechanism using steam or other disrupting fluids to regulate the flow rate and temperature of the smelt, particularly during abnormal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shatter jet nozzles are used to disrupt smelt flow, then normal smelt flow is adequately controlled, but abnormal or heavy smelt flows cannot be effectively mitigated
Solution Approach 1:
The patent implements a dynamically adjustable restrictor assembly that can modify its opening degree in response to varying smelt flow conditions. The restrictor plate is positioned at an angle to the smelt flow and can be adjusted remotely to control the flow rate, allowing the system to adapt from normal to abnormal heavy smelt flow conditions effectively
Solution Approach 2:
The restrictor assembly acts as an intermediary device between the smelt flow source and the dissolving tank. By introducing this intermediate control mechanism, the system can regulate smelt flow rate and disrupt explosive reactions regardless of whether the incoming smelt flow is normal or abnormal
2Object-affected harmful factors
If the restrictor plate is positioned to block smelt flow during abnormal operations, then explosive reactions are reduced, but smelt flow control complexity increases
Solution Approach 1:
The control mechanism for the restrictor plate is extracted and positioned remotely from the high-temperature smelt flow environment. This allows operators to adjust the restrictor plate opening degree safely from a remote location, reducing operational complexity and safety risks while maintaining effective control over smelt flow and explosive reactions
Solution Approach 2:
The patent replaces direct mechanical intervention in the hot smelt flow zone with a remotely controllable mechanism. The restrictor plate can be adjusted via remote actuation, substituting the need for complex mechanical systems in the hazardous environment with a simpler, safer control approach
3Strength
If cooling mechanism is applied to the restrictor assembly, then the restrictor can withstand heavy smelt flows, but energy consumption increases
Solution Approach 1:
The cooling mechanism is activated preliminarily or proactively when abnormal heavy smelt flow conditions are detected or anticipated. By applying cooling before the restrictor assembly reaches critical temperature, the system protects the restrictor from thermal damage while minimizing unnecessary energy consumption during normal operation
Solution Approach 2:
The cooling system operates based on feedback from smelt flow conditions and restrictor temperature. When heavy smelt flow is detected, cooling is activated to protect the restrictor assembly; when normal flow conditions prevail, cooling is reduced or stopped, optimizing energy consumption while maintaining required thermal protection
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 the frequency and intensity of explosive reactions in the dissolving tank by controlling the smelt flow rate and temperature, enhancing safety and reducing equipment damage during heavy smelt flows.
Implementation Method 1
coupled with a cooling mechanism using steam or other disrupting fluids to regulate the flow rate and temperature of the smelt
Implementation Method 2
A smelt restrictor assembly with a rotatable restrictor plate and actuator is introduced, allowing for remote control of smelt flow blockage
Implementation Method 3
The disruption of the smelt flow may be to breakup a smelt stream into droplets or pieces as the stream flows from the spout
Data Source
Figure 1
Figure 2
AI summary
The amount or extent of expositions as a result of hot smelt from a pulp mill recovery boiler impacting cool liquid in a dissolving tank is reduced more effectively by regulating the smelt flow via a restrictor assembly. The restrictor assembly may be positioned to permit the smelt to flow, unrestricted, from the recovery boiler to the dissolving tank, or the restrictor assembly may be positioned so as to fully or partially block the smelt flow from the boiler to the dissolving tank. In some embodiments, a source of cooling fluid may be coupled to the restrictor assembly so as to assist in cooling parts of the restrictor assembly when hot smelt is in contact with the assembly.