Heat Exchanger Safety Device for Rapid Pressure Relief

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Solution Overview

Problem

Conventional heat exchangers, particularly salt bath coolers, face challenges in rapid and reliable pressure relief during pipe ruptures, leading to potential damage and safety hazards due to the buildup of high pressure from evaporating water under high temperatures and poor feed water quality causing stress and corrosion.

Innovation Solution

A heat exchanger design featuring a safety device located near the base, which acts as an emergency release to alleviate pressure by allowing the vapor to expand into a smaller column, and a collecting device to manage the displaced heat transfer medium, ensuring quick pressure reduction and containment of the medium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional emergency relief devices (bursting disc, overflow nozzle) are used at the top of the heat exchanger, then pressure relief is provided, but the steam must pass through or displace the entire heat transfer medium column, causing difficulty in pressure relief and potential housing rupture

Engineering Contradiction:
Improvepressure relief reliabilityVSAvoidpressure relief mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The heat exchanger is divided into multiple sections with intermediate relief openings distributed along the tube bundle. This segmentation allows steam to escape at multiple locations rather than having to traverse the entire height of the heat transfer medium column, significantly reducing the displacement burden and enabling reliable pressure relief.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of providing relief only at the top (single point), the invention distributes relief openings along the vertical dimension of the heat exchanger. This multi-level arrangement creates multiple escape paths for steam, transforming the pressure relief mechanism from a single-point discharge to a distributed system that reduces the workload on each individual relief device.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the heat exchanger housing is designed to withstand high pressures from steam displacement, then safety is improved, but the housing design becomes more complex and costly

Engineering Contradiction:
Improvehousing safetyVSAvoidhousing design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The intermediate relief openings act as preemptive pressure release points that prevent excessive pressure buildup before it can reach the housing. By providing multiple early escape routes for steam, the system cushions against potential pressure surges, allowing the housing to be designed for normal operating pressures rather than extreme pressure scenarios.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If the heat exchanger height is reduced to 4-8m as in conventional designs, then installation is easier, but pipe ruptures in the lower area are more difficult to detect and pressure relief is less effective

Engineering Contradiction:
Improveinstallation easeVSAvoidpressure relief effectiveness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Different sections of the heat exchanger are equipped with relief openings tailored to local conditions. The distribution of relief openings along the tube bundle ensures that each section has appropriate pressure relief capability, with intermediate openings specifically addressing the vulnerability of lower-area pipes while maintaining overall system compactness.

Inventive Principle:
Principle #3Local quality

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

The solution enables rapid and safe pressure relief without subjecting the heat exchanger housing to excessive pressures, reducing the risk of damage and ensuring safety by containing the heat transfer medium, thus eliminating the need for additional pressure-resistant design features beyond 5 bar.

Implementation Method 1

a liquid heat carrier (7) which is discharged from a reactor (27) to be cooled, the liquid heat carrier (7) serving to absorb heat in a convective manner

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

the water suddenly evaporates, so that high pressure builds up spontaneously

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3120099B1Heat exchanger, reactor arrangement comprising said heat exchanger, and method for temperature control of a reactor
Publication Date: 2019.06.12 BASF SE
  • EP3120099B1 patent drawingFigure 1
  • EP3120099B1 patent drawingFigure 2

AI summary

The invention relates to a heat exchanger (1) which comprises a bundle of at least two heat exchanger tubes (3), wherein the bundle of heat exchanger tubes (3) is aligned vertically and terminated downward by a heat exchanger tube floor (31), a heat exchanger housing (5) enclosing the bundle of heat exchanger tubes (3), wherein a liquid heat transfer medium (7) circulates in the bundle of heat exchanger tubes (3) in the heat exchanger housing (5), a heat exchanger hood (9) terminating the heat exchanger housing (5) upward, a heat exchanger floor (11) terminating the heat exchanger housing (5) downward, an inlet (13) into the heat exchanger (1) on the heat exchanger housing (5) for the heat transfer medium (7), an outlet (15) out of the heat exchanger (1) on the heat exchanger housing (5) for the heat transfer medium (7), and an emergency relief connection (17) which is arranged near the heat exchanger hood (9). The heat exchanger (1) is characterized in that the heat exchanger (1) has a safety device (19) which is arranged near the heat exchanger floor (11). The invention furthermore relates to a reactor arrangement (101) which comprises a reactor (27), a heat exchanger (1) connected to the reactor (27) according to the present invention and a pump (29) connected to the reactor (27) and/or the heat exchanger (1) for circulating at least one part of the liquid heat transfer medium (7). Finally, the invention relates to a method for temperature control of a reactor (27) and the use of the heat exchanger (1) according to the invention.