Indirect Fluid Preheating With Variable Medium Flow Control
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Solution Overview
Problem
Existing preheating technologies for furnaces struggle with efficiently preheating fluids when the flow rate and temperature of hot fumes vary significantly during operation, particularly in discontinuous furnaces where combustion and fume production are intermittent.
Innovation Solution
A method involving an intermediate heat transfer medium that adjusts its flow rate based on various temperature parameters to optimize heat exchange between hot fumes and the fluid to be preheated, ensuring efficient preheating even with fluctuating furnace conditions, using a pipeline system with a first and second wall for heat exchange stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If indirect heat exchange is used with a fixed flow rate intermediate medium, then preheating is effective for continuous furnaces with stable fume flow, but the system cannot adapt to significant variations in fume flow rate and temperature in discontinuous furnaces
Solution Approach 1:
The patent applies dynamics by making the flow rate of the intermediate heat transfer medium variable rather than fixed. The flow rate is dynamically adjusted based on the actual fume flow rate and temperature conditions in discontinuous furnaces, allowing the heat exchange system to adapt to significant variations in operational parameters while maintaining preheating effectiveness
Solution Approach 2:
The patent implements feedback control by monitoring the fume flow rate and temperature, and using this information to regulate the flow rate of the intermediate medium. This closed-loop control system automatically adjusts the heat transfer process to match actual furnace conditions, improving adaptability without requiring complex manual intervention
2Adaptability or versatility
If the flow rate of the intermediate medium is increased to adapt to varying fume conditions, then adaptability improves, but energy loss increases due to excessive medium circulation
Solution Approach 1:
The patent applies partial action by adjusting the intermediate medium flow rate to match the actual heat recovery needs rather than maintaining constant high flow. The system uses only the necessary amount of medium circulation required for effective heat exchange under current fume conditions, avoiding excessive energy consumption while maintaining adaptability to varying furnace operational states
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 the furnace's operational state, and effectively recycling thermal energy, even in furnaces with varying fume flow rates and temperatures, enhancing energy efficiency and preventing thermal damage.
Implementation Method 1
The flue gases in the pipe heat the intermediate medium in the chamber by heat exchange through a wall, called the 'first wall'
Implementation Method 2
heat exchange through a wall that separates the fluid to be heated from the hotter fluid
Implementation Method 3
The heated medium, which is in the chamber, preheats the fluid which is in the at least one conduit by heat exchange through the second wall
Implementation Method 4
preheated by direct heat exchange with the intermediate fluid heated in the first stage through a second wall
Data Source
Figure 1
Figure 2
AI summary
Method for indirectly preheating a fluid 40 upstream of a furnace, wherein the fluid is preheated by indirect heat exchange with fumes 10 discharged from the furnace through a medium 31 in a chamber 20, and wherein the flow rate of the medium 31 in the chamber 20 is adjusted on the basis of at least one of the following temperatures: the temperature of the discharged fumes 10, the temperature of the medium 32 in the chamber 20, the temperature of the preheated fluid 42, and the temperature of the wall 21 separating the discharged fumes 31 from the medium 31 in the chamber 20.