Fluidized Bed Heat Exchanger Segmentation for Boiler Pressure Loss
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Solution Overview
Problem
Existing heat exchangers in circulating fluidized bed boilers face inefficiencies and lack flexibility, particularly in achieving high steam temperatures and reheating temperatures, especially at low loads, due to inadequate heat exchange surface area and pressure losses associated with large boiler sizes.
Innovation Solution
A heat exchanger design featuring two connected heat exchange chambers in series, with means for introducing hot solids from both external and internal circulation, allowing for controlled solid flow and temperature management, including direct introduction of hot solids from the furnace into the second heat exchange chamber to maximize inlet temperature and achieve high reheating temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the volume of the fluidized bed in the heat exchange chamber is increased to raise heat exchange efficiency, then the heat exchange surface increases, but the pressure loss of the fluidizing gas increases
Solution Approach 1:
The heat exchange chamber is divided into two separate chambers instead of using one large chamber. This segmentation allows the system to achieve sufficient total heat exchange surface area while maintaining lower pressure losses in each individual chamber, as the fluidizing gas does not need to traverse a single large volume
2Productivity
If the height of the fluidized bed is increased to increase heat exchange surface, then the heat exchange efficiency improves, but the pressure loss of the fluidizing gas increases
Solution Approach 1:
Instead of increasing the height of a single fluidized bed, the invention uses two separate heat exchange chambers arranged in parallel, effectively distributing the heat exchange function across multiple smaller units rather than one tall unit
3Productivity
If the width and depth of the fluidized bed are increased to increase heat exchange surface, then the heat exchange efficiency improves, but the structural complexity and space consumption increase
Solution Approach 1:
The invention divides the heat exchange function into two separate chambers rather than expanding a single chamber in all dimensions, which can lead to more manageable structural configurations and potentially reduced space consumption depending on the arrangement
4Productivity
If a single large heat exchange chamber is used to achieve high heat exchange efficiency, then the heat exchange surface is sufficient, but the adjustability of heat exchange efficiency is inadequate
Solution Approach 1:
By dividing the heat exchange system into two separate chambers, the invention enables independent control and adjustment of each chamber's operation, providing greater flexibility and adaptability in regulating heat exchange efficiency according to different operational requirements
Solution Approach 2:
The parallel arrangement of two heat exchange chambers allows for dynamic adjustment of the system's operation, where each chamber can be independently controlled to optimize performance under varying load conditions
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 design enhances heat exchange efficiency and flexibility, enabling the attainment of high superheating and reheating temperatures across all boiler loads while minimizing pressure losses and space consumption, particularly effective in large once-through utility boilers.
Implementation Method 1
heat exchange chambers arranged in the external hot circulation
Implementation Method 2
heat exchangers arranged in the backpass of the boiler, by means of water tube panels of the furnace and backpass walls
Implementation Method 3
first means for fluidizing solids, a second inlet channel for introducing solids into the second heat exchange chamber, which is provided with second means for fluidizing solids
Data Source
Figure 1
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Figure 3
AI summary
A heat exchanger (30) and a circulating fluidized bed boiler (10) with a heat exchanger comprising a first (36) and a second (38) fluidized bed heat 5 exchange chamber arranged in connection with a furnace (12) of the circulating fluidized bed boiler, a first inlet channel (18) for introducing hot solids from a particle separator of the external circulation of the circulating fluidized bed boiler (10) into the first heat exchange chamber (36), a second inlet channel (58) for introducing solids to the second heat exchange chamber (38), first discharge 10 means (54, 56) for removing a first portion of the cooled solids from the first heat exchange chamber (36) to the second inlet channel (58) and second discharge means (61) for removing cooled solids form the second heat exchange chamber (38) to the furnace (12), said heat exchanger comprising inlet means (64) for introducing hot solids directly from the internal circulation of 15 the furnace (12) to the second heat exchange chamber (38). The heat exchanger (30) also preferably comprises third discharge means (72, 74, 76) for removing a second portion of the cooled solids from the first heat exchange chamber (36) directly to the furnace.