Wet Natural Gas Sampling Probe with Heating Zone
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Solution Overview
Problem
Current natural gas sampling technologies are inadequate for accurately capturing representative samples of 'wet' natural gas, which contains entrained liquids, due to phase changes and operational challenges, leading to inaccuracies in BTU content measurement and custody transfer.
Innovation Solution
A static isokinetic sampling process that captures a volume of the gas stream in a streamlined container, breaks up entrained liquids into small droplets, and then withdraws the sample outside the flow stream for analysis, ensuring accurate representation of the gas and liquid phases without requiring flow rate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sampling methods are used for wet natural gas, then the sampling process is simple, but the measurement precision of BTU content is poor due to phase changes and liquid separation
Solution Approach 1:
The sampling system is divided into distinct functional segments: a sampling probe for isokinetic collection, a heating zone for phase stabilization, and a separation chamber for liquid-gas separation. This segmentation allows each component to perform its specific function optimally, ensuring accurate representation of wet gas composition while maintaining manageable system complexity
Solution Approach 2:
The sampling probe performs preliminary isokinetic collection of wet gas with entrained liquids before any phase changes can occur. The heating zone then applies preliminary thermal action to stabilize the sample at elevated temperatures, preventing condensation and phase separation during subsequent handling and analysis
2Measurement precision
If isokinetic sampling is performed in rapidly changing pipeline velocities, then the sample representation is accurate, but the device complexity increases due to flow control requirements
Solution Approach 1:
Instead of actively controlling and matching the sampling flow rate to pipeline velocity (conventional isokinetic approach), the invention inverts the approach by using a static container that passively captures the gas stream. The container's geometry and positioning ensure isokinetic sampling without requiring active flow control mechanisms, simplifying operation while maintaining accuracy
Solution Approach 2:
The streamlined container design allows the gas stream itself to perform the sampling function by filling the container through its own kinetic energy. The system self-regulates to maintain isokinetic conditions based on the natural flow dynamics, eliminating the need for external flow control devices or complex operational procedures
3Measurement precision
If entrained liquids are removed from the sample, then the sampling process is simplified, but the measurement precision of BTU content deteriorates due to loss of liquid hydrocarbon components
Solution Approach 1:
The system changes the temperature parameter by heating the sample in the heating zone, which alters the phase behavior of entrained liquids. This parameter change prevents condensation and maintains liquids in a suspended state, allowing accurate measurement of liquid hydrocarbon components without requiring complex liquid handling or separation systems
4Stability of the object's composition
If the sample is withdrawn outside the flow stream, then phase changes are avoided, but the sampling time increases
Solution Approach 1:
The sample container is pre-positioned within the flow stream to perform preliminary isokinetic collection directly at the sampling point. This preliminary action captures the wet gas composition before any phase changes can occur, then the container is rapidly withdrawn and sealed, minimizing the time the sample is vulnerable to composition changes while ensuring accurate initial collection
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 method provides a superior sampling solution for wet gas streams, ensuring accurate BTU content measurement and overcoming phase changes triggered by flow, pressure, and temperature, while maintaining isokinetic sampling even with rapidly changing pipeline velocities.
Implementation Method 1
a streamlined container suspended in said source fluid to capture a volume of said source fluid flowing through a conduit or pipeline by isokinetic flow conditions
Implementation Method 2
said container is then heated in a heating zone to vaporize the liquid entrained in said sample gas to render the sample entirely in gas phase
Implementation Method 3
said constriction member terminating with a sharp lip to break up entrained liquids into droplets
Implementation Method 4
breaks up entrained liquid in the gas stream into small liquid droplets, so that they are suspended in the flowing gas stream to form a sampling area
Data Source
AI summary
A system for on-stream sampling of pressurized process gas such as natural gas or the like, said pressurized process gas having liquid entrained therein, or otherwise referenced as “wet”. The preferred embodiment of the present invention contemplates a system for obtaining an accurate sample of said wet process gas, as well as providing an apparatus for obtaining same.