Controllable injection for implementing different local refrigerant distribution
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Solution Overview
Problem
Coil wound heat exchangers in natural gas liquefaction plants face performance losses due to maldistribution of refrigerant across the pipe bundle, leading to uneven heat transfer and local temperature differences.
Innovation Solution
A coil wound heat exchanger design with helically wound pipes featuring nozzles at different heights and layers, connected to adjustable valves for targeted refrigerant injection and withdrawal, allowing for controlled distribution of refrigerant across the bundle to counteract maldistribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If refrigerant is introduced into the shell space through a single point, then the structure is simple, but maldistribution of refrigerant occurs leading to performance losses
Solution Approach 1:
The single refrigerant introduction point is segmented into multiple introduction points distributed across different heights and radial positions. First pipes are connected to the shell space at multiple locations (different heights along the longitudinal axis and different radial positions), allowing refrigerant to be introduced at multiple points simultaneously, thereby eliminating maldistribution while maintaining structural simplicity
Solution Approach 2:
Different regions of the shell space are provided with different refrigerant introduction characteristics. Pipes are positioned at specific heights and radial locations to create locally optimized refrigerant distribution, ensuring each region receives appropriate refrigerant flow based on its specific heat transfer requirements
2Productivity
If multiple pipes are used to distribute refrigerant at different locations, then refrigerant distribution is improved, but device complexity increases
Solution Approach 1:
The first pipes serve multiple functions simultaneously: they act as heat exchange conduits, refrigerant distribution channels, and structural support elements. This multi-functionality reduces the need for separate dedicated distribution components, thereby improving refrigerant distribution without proportionally increasing device complexity
Solution Approach 2:
The pipe arrangement transitions from a single-plane configuration to a three-dimensional distribution network extending along the longitudinal axis and radial direction. Pipes are positioned at multiple heights and radial positions, creating a spatial distribution pattern that achieves uniform refrigerant delivery without requiring an excessive number of components
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 ensures uniform refrigerant distribution and improved heat transfer efficiency by allowing precise control of refrigerant flow, reducing local temperature variations and enhancing overall performance.
Implementation Method 1
A first refrigerant, which evaporates by means of a falling film, is introduced on the shell side
Implementation Method 2
a first refrigerant can be introduced or injected into the shell space, e.g., as a two-phase flow (liquid/gaseous)
Data Source
AI summary
A heat exchanger for indirectly transferring heat between a process medium and at least one first refrigerant, comprising: a shell which surrounds a shell space and extends along a longitudinal axis; and a pipe bundle which is disposed in the shell space and extends along the longitudinal axis of the shell from a lower end to an upper of the pipe bundle in the shell space; wherein; the pipe bundle has a plurality of first pipes for receiving the first refrigerant; the first pipes are wound helically onto a core pipe of the heat exchanger. According to the invention, the first pipes each have an end which is formed by at least one nozzle via which the first refrigerant can be introduced into the shell space, the ends being disposed along the longitudinal axis of the shell at different heights.