Method for preheating a fluid upstream of a furnace
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Solution Overview
Problem
Existing oxy-fuel combustion technologies struggle to efficiently preheat fluids for furnaces with varying flue gas flow rates and temperatures, particularly in batch furnaces where hot gas production is intermittent.
Innovation Solution
A process involving a heat transfer medium that adjusts its flow rate based on multiple temperature parameters to optimize heat recovery and preheating, using a chamber with a first wall for initial heat exchange with flue gases and a second wall for preheating the fluid, ensuring efficient energy transfer and safety by regulating temperatures within predetermined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If indirect heat exchange is used with a fixed flow rate of heat transfer medium, then the system is simple to operate, but it cannot adapt to significant variations in flue gas flow rate and temperature
Solution Approach 1:
The patent applies dynamics by making the flow rate of the heat transfer medium variable rather than fixed. The flow rate is dynamically adjusted based on the actual flue gas flow rate and temperature conditions, allowing the system to adapt to varying operational modes including batch furnace operations with intermittent hot gas production.
Solution Approach 2:
The patent implements feedback control by continuously monitoring flue gas temperature and flow rate, then using this information to regulate the heat transfer medium flow rate. The control system compares actual conditions with desired conditions and adjusts the flow rate accordingly to maintain optimal heat exchange efficiency.
2Adaptability or versatility
If the flow rate of heat transfer medium is increased to adapt to varying conditions, then adaptability improves, but energy loss increases
Solution Approach 1:
The patent changes the flow rate parameter of the heat transfer medium dynamically based on flue gas conditions. By adjusting this parameter rather than maintaining a constant high flow rate, the system adapts to varying furnace operations while minimizing energy loss from flue gases that would otherwise be wasted.
3Loss of energy
If a control system regulating flow rate based on multiple temperature parameters is implemented, then energy efficiency is optimized, but device complexity increases
Solution Approach 1:
The control system uses feedback from multiple temperature sensors (flue gas temperature, heat transfer medium temperature, preheated fluid temperature) to continuously optimize heat exchange efficiency. This multi-parameter feedback approach maximizes energy recovery while the control system integrates these measurements to regulate flow rate effectively.
Solution Approach 2:
The control system serves multiple functions: it monitors flue gas conditions, regulates heat transfer medium flow rate, ensures safe operation temperatures, and optimizes energy recovery. This multi-functionality justifies the increased complexity by providing comprehensive control over the heat exchange process.
4Loss of energy
If high preheating temperatures are achieved, then energy efficiency improves, but safety risks increase
Solution Approach 1:
The control system continuously monitors temperatures at multiple points (flue gas, heat transfer medium, preheated fluid, and wall temperatures) and uses this feedback to maintain safe operating conditions. When temperatures approach safety thresholds, the system automatically adjusts the heat transfer medium flow rate to prevent dangerous conditions while still achieving high preheating temperatures for energy efficiency.
Solution Approach 2:
The control system takes preliminary anti-action by monitoring wall temperatures and predicting potential overheating conditions before they become dangerous. By adjusting the heat transfer medium flow rate in advance based on wall temperature measurements, the system prevents safety issues from occurring while maintaining efficient heat exchange.
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 allows for high preheating temperatures while maintaining safety, adapting to varying furnace operations, and optimizing energy efficiency by adjusting the flow rate of the heat transfer medium in response to temperature changes, thus enhancing the efficiency of fluid preheating in furnaces with fluctuating conditions.
Implementation Method 1
The flue gases in the duct heat the intermediate medium in the chamber by heat exchange across a wall, referred to as first wall, separating the intermediate medium which is in the chamber from the flue gases which are in the discharge duct
Implementation Method 2
The heated medium, which is in the chamber, preheats the fluid that is in the at least one line by heat exchange across the second wall
Data Source
AI summary
Method for indirectly preheating a fluid upstream of a furnace, wherein the fluid is preheated by indirect heat exchange with fumes discharged from the furnace through a medium in a chamber, and wherein the flow rate of the medium in the chamber is adjusted on the basis of at least one of the following temperatures: the temperature of the discharged fumes, the temperature of the medium in the chamber, the temperature of the preheated fluid, and the temperature of the wall separating the discharged fumes from the medium in the chamber.