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Mastering the Flow: How to Size Piping in a Triethylene Glycol Dehydration Unit

Triethylene Glycol (TEG) Dehydration Units are instrumental in removing moisture from natural gas streams, ensuring that the gas meets the required specifications for transportation and use. One critical aspect of designing these units is properly sizing the piping system. In this blog post, we'll explore the key considerations and steps involved in sizing piping for a TEG Dehydration Unit, helping you navigate the intricate flow of this essential process.

The Importance of Sizing Piping

Sizing the piping system in a TEG Dehydration Unit is crucial for maintaining operational efficiency and ensuring that the unit functions as intended. Properly sized piping:

  1. Ensures Optimal Flow: It ensures that the TEG solution and gas flow rates are within design parameters, preventing bottlenecks or overflows.

  2. Reduces Pressure Drops: Correct sizing minimizes pressure drops, ensuring that the system operates at the desired pressure levels.

  3. Prevents Erosion and Corrosion: Proper pipe sizing reduces the risk of erosion and corrosion, which can result from high flow velocities or excessive turbulence.

Steps to Size Piping in a TEG Dehydration Unit

  1. Determine Flow Rates: The first step in sizing piping is to determine the flow rates of the gas and TEG. This involves calculating the maximum anticipated flow of both components based on the unit's capacity and the properties of the gas stream.

  2. Select Pipe Material: Choose the appropriate pipe material based on factors such as the temperature, pressure, and corrosiveness of the fluids being transported. Stainless steel and carbon steel are commonly used materials for TEG units.

  3. Calculate Pipe Diameter: Use established engineering equations and calculations to determine the required pipe diameter for both the gas and TEG solution lines. These calculations take into account factors like flow rate, fluid properties, pressure drop limitations, and pipe roughness. The pipe diameter is going to be calculated assuring that the gas velocity is under both the calculated erosional velocity and 70 feet/sec. The glycol velocity in the piping should be under 5.9 ft/sec due to the glycol viscosity.

  4. Consider Pressure Drop: Ensure that the pressure drop along the piping system is within acceptable limits. Excessive pressure drops can lead to inefficient operation and may require additional pumping.

  5. Include Safety Margins: Add safety margins to your calculations to account for variations in operating conditions and unforeseen changes in flow rates. This ensures that the piping system can handle fluctuations without compromising performance.

  6. Plan for Maintenance: Factor in accessibility for maintenance and potential future expansions or modifications when designing the piping layout.

  7. Compliance with Codes and Standards: Ensure that the design and sizing of the piping system comply with industry-specific codes and standards, such as ASME B31.3 for process piping.

Seek Professional Guidance

Sizing piping in a TEG Dehydration Unit is a complex task that requires a deep understanding of fluid dynamics, engineering principles, and industry-specific standards. It is advisable to engage a qualified engineer or a team of experts who specialize in process engineering and piping design to ensure that the system is designed optimally and safely.


Properly sizing the piping system in a Triethylene Glycol Dehydration Unit is paramount to its efficiency and reliability. By carefully considering flow rates, material selection, pressure drop, safety margins, and compliance with industry standards, you can ensure that your TEG unit operates smoothly, effectively removing moisture from natural gas streams and delivering dry, high-quality gas to meet energy demands.

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