Helical Evaporator for Liquefied Gas Sampling

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Solution Overview

Problem

Existing devices for continuous analysis of hydrocarbon mixtures from liquid gas lines suffer from fractionation issues due to differences in boiling points, leading to unreliable and fluctuating results, and often have significant time delays between sampling and analysis.

Innovation Solution

A device with an evaporator unit featuring a downward screw and upward spiral evaporation sections in thermal contact with a heatable body, combined with a wire mesh for enhanced mixing and heat transfer, and a separating device to manage residual liquids, reduces fractionation and minimizes time delays by ensuring efficient energy transfer and pressure reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If thermal energy is supplied to vaporize the sample quickly, then evaporation speed is improved, but fractionation increases due to excessive heating power

Engineering Contradiction:
Improveevaporation speedVSAvoidanalysis reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The evaporator unit is divided into multiple heating zones (first heating zone, second heating zone, third heating zone) with different heating powers. The first heating zone has higher heating power for rapid initial vaporization, while the second and third zones have lower heating powers to complete evaporation without excessive fractionation. This segmentation allows the system to achieve both fast evaporation and reliable analysis.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the sample line receive different amounts of thermal energy based on their specific needs. The sample line sections in the first heating zone receive higher thermal energy for rapid vaporization, while sections in the second and third heating zones receive lower thermal energy to complete the process without causing fractionation. This local differentiation of heating quality resolves the contradiction between speed and reliability.

Inventive Principle:
Principle #3Local quality

2Duration of action of stationary object

If the sample line is heated to ensure complete vaporization, then evaporation completeness is improved, but fractionation increases

Engineering Contradiction:
Improvevaporization completenessVSAvoidanalysis reliability
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The heating process is segmented into three distinct zones with progressively lower heating powers. This ensures that vaporization is completed thoroughly across all sample components while preventing excessive heating that would cause fractionation. The segmented approach maintains both completeness and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating power parameter is changed progressively across different zones of the evaporator unit. The first heating zone operates at higher power to initiate rapid vaporization, while the second and third zones operate at lower powers to complete the process. This parameter change ensures complete vaporization without causing fractionation, resolving the contradiction between completeness and reliability.

Inventive Principle:
Principle #35Parameter changes

3Stress or pressure

If a heated pressure regulator is used for vaporization, then pressure control is improved, but fractionation increases to unacceptable levels

Engineering Contradiction:
Improvepressure controlVSAvoidanalysis reliability
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The pressure control and heating functions are segmented into separate components. The pressure regulator controls pressure independently, while the evaporator unit with its segmented heating zones handles vaporization. This separation allows pressure control to be optimized without causing the fractionation problems associated with heated pressure regulators.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating function is extracted from the pressure regulator and placed in a separate evaporator unit. This extraction eliminates the fractionation problem caused by heated pressure regulators while maintaining effective pressure control. The heating is then applied in a controlled, segmented manner in the evaporator unit.

Inventive Principle:
Principle #2Taking out (Extraction)

4Quantity of substance

If the sample line is made larger to reduce pressure drop, then flow capacity is improved, but time delay increases

Engineering Contradiction:
Improveflow capacityVSAvoidtime delay
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The sample line diameter is made variable along its length, with the diameter decreasing in the direction of flow. This dynamic configuration allows the line to have sufficient capacity for flow while creating a pressure gradient that accelerates the sample through the line, reducing time delay. The dynamic diameter change resolves the contradiction between flow capacity and time delay.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The geometric parameter of the sample line (diameter) is changed progressively along its length. The line starts with a larger diameter to accommodate flow capacity requirements, then transitions to smaller diameters to increase flow velocity and reduce pressure drop. This parameter change allows the system to maintain both adequate flow capacity and minimal time delay.

Inventive Principle:
Principle #35Parameter changes

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 configuration allows for reliable and continuous analysis of hydrocarbon samples with reduced fractionation and minimized time delays, enabling accurate and reproducible results.

Implementation Method 1

a first evaporation section of the sample line runs in a downward screw and is in thermally conductive contact with the heatable body. Furthermore, the invention provides that a second evaporation section of the sample line, located downstream of the first evaporation section, runs in an upward spiral and is also in thermally conductive contact with the heatable body

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The helical line routing, in conjunction with the thermally conductive contact to the heatable body, ensures a particularly effective and spatially defined transfer of thermal energy to the flowing sample medium and a simultaneous reduction in pressure

Methodology Applied
Scientific EffectPressure reduction: Depressurisation

Implementation Method 3

US 2012/0138268 A1 discloses a heat exchanger in which cooling liquid is guided through a winding pipeline. A wire mesh can be provided to create turbulence in the flow

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 4

an evaporator unit to be arranged outside the liquid gas line for at least partially evaporating fluids flowing through the sample line

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3454035B1Devices for continuously sampling and preparing a fluid sample from a liquefied gas conveying process line
Publication Date: 2022.01.12 SICK AG
  • EP3454035B1 patent drawingFigure 1
  • EP3454035B1 patent drawingFigure 2
  • EP3454035B1 patent drawingFigure 3~4

AI summary

A device for taking and processing a fluid sample from a liquefied gas line comprises a sample line which has an open line end that can be inserted into the liquefied gas line and an evaporator unit to be arranged outside the liquefied gas line for at least partially evaporating fluids flowing through the sample line.The evaporator unit comprises at least one heatable body, wherein a first evaporation section of the sample line runs in a downward screw and is in thermally conductive contact with the heatable body, and wherein a second evaporation section of the sample line located downstream of the first evaporation section runs in an upward screw and is also in thermally conductive contact with the heatable body, and/or the open line end (29) is formed at a sampling section (27) of the sample line (25) which has a reduced cross-sectional area compared to the subsequent sample line section.