Heat Exchanger Tube Bundle Flow Inversion
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Solution Overview
Problem
Existing heat exchanger designs for horizontal heat recovery steam generators face inefficiencies in heat recovery due to unfavorable cross-flow properties and complex construction, leading to reduced heat transfer efficiency and increased costs, while also struggling to maintain stable feed water velocity and prevent flow instabilities.
Innovation Solution
A heat exchanger tube bundle design featuring a sequence of bottom and top headers with specific configurations of tube rows for alternating flow directions, eliminating the need for partition plates and crossovers, allowing for optimized up- and downflow dynamics and improved heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If partition plates are welded inside headers to create subsequent circuits, then feed water velocity can be maintained and flow stability improved, but heat recovery efficiency is reduced due to unfavorable cross-flow properties
Solution Approach 1:
Instead of using partition plates to force water through multiple passes in the same rack (creating cross-flow), the invention inverts the approach by connecting bottom headers to top headers via tube rows, allowing water to flow in a single direction through each tube row. This eliminates the cross-flow configuration and enables all exhaust gas to be exposed to cold water, thereby improving heat recovery efficiency while maintaining flow stability through the header-tube row header connection structure.
2Loss of energy
If single tube rows are connected in series to inlet and outlet headers, then heat recovery efficiency is improved, but device complexity and construction difficulty increase
Solution Approach 1:
The invention segments the heat exchanger into a sequence of modular header units, where each unit comprises a bottom header, a top header, and tube rows connecting them. This segmentation allows for simplified construction of individual modules while achieving high heat recovery efficiency through the series connection of these modules, balancing both efficiency and constructability.
Solution Approach 2:
The invention merges the functions of inlet and outlet headers into unified bottom and top headers that serve multiple tube rows. By combining these header functions and connecting them directly via tube rows without requiring external crossovers or complex piping, the design reduces construction complexity while maintaining improved heat recovery efficiency.
3Productivity
If multiple tube rows are connected to inlet and outlet headers to maximize heat exchange surface area, then heat transfer effectiveness is improved, but device complexity increases due to required crossovers and external piping
Solution Approach 1:
The invention merges multiple tube rows into a unified structure where all tube rows connect directly between bottom and top headers. This eliminates the need for external crossovers and complex piping systems, reducing device complexity while maintaining large heat exchange surface area through the multiple tube rows configured in parallel between the headers.
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 recovery efficiency, simplifies construction, reduces costs, and stabilizes feed water flow, achieving a more compact and robust heat exchanger configuration that addresses the inefficiencies of previous designs.
Implementation Method 1
heat exchanger tube bundle... for exchanging heat like a flue gas
Implementation Method 2
fluid is guided through the tubes of the tube bundle... heat transfer efficiency
Data Source
AI summary
A heat exchanger tube bundle of horizontal gas path design is presented, the tube bundle comprising a sequence of bottom headers and corresponding top headers, wherein each unit of the sequence comprises a row of tubes, wherein each bottom header-is fluidly connected to a corresponding top header-via at least two similar tube rows for passing a fluid in a first direction between the bottom header and the top header, respectively, and wherein each unit of the sequence further comprises at least one further tube row in fluid connection with one of said bottom or top header, wherein the further tube row is further fluidly connected to a header of a subsequent unit, and wherein the further row's tubes are configured for passing the fluid in a second direction opposite to the first direction. Moreover, a related heat recovery steam generator-and combined cycle power plant are presented.