Selecting Among Dry Gas Seal Support Systems for Northern California Industries
by Malik Durojaiye, on 10/20/21 9:00 AM
Dry gas seal support systems allow for the smooth and efficient operation of dry gas seals. If the seal support system is properly aligned with the gas seal configuration and the conditions used in processing, then the seal support system will increase the reliability and resilience of the seal to operating conditions (e.g. high temperature, high pressure, and corrosive materials used in processing). Components of the seal support system will prevent liquid from forming in the seal and thus, avoid critical breakdown of processing. Further, the components of the seal system will monitor the dry gas seal for leakage. If leakage occurs, the seal support systems have alarms to indicate if a shutdown is necessary to prevent additional gas leakage. This leaked gas can also be contained by the seal support system if there is a seal failure. Finally, components of the seal support system manage the flow of gases to the dry gas seal allowing for processed gases to be moved to the vent system. In all, the seal support system contributes in multiple ways to the effective operation of dry gas seals.
The dry gas seal support system has several components that are important for its ability to maintain the dry gas seal and continued operations. These components include a seal panel, a compressor, and a rotating seat. These components need to be properly configured with the dry gas seal configuration, which includes the following options: single seal, tandem seal, tandem seal with intermediate labyrinth, and double opposed seal. To ensure safe and efficient operations, refineries should consult with seal support system experts on how to select a dry gas seal support system that can seamlessly integrate into operations.
In this article, we will discuss the different gas seal configurations. After, we will discuss the components of the seal support system and the reasons for choosing specific designs.
Types of Dry Gas Seal Configurations
When selecting a dry gas seal system configuration it is important to consider the configuration that best fits operation parameters. These include the pressure, temperature, and the type of chemicals used in operation. The following are the most common dry gas seal configuration designs.
The single seal design is often used with non-toxic gases that do not damage the environment. Operations that use a single seal design often utilize common gasses such as carbon dioxide, air, and nitrogen. Single seal designs do not provide the same level of protection as other seal configurations from leakage. However, they can be cost-effective if leakage is less of a concern.
A double seal design utilizes opposing seals to create a stretch of buffer or barrier gas. This can be especially useful when leakage is needed to be prevented at all costs. Operations that work with toxic or environmentally harmful gasses may utilize a double seal configuration. Further, when using especially corrosive gas (for example hydrogen gas) this design could be beneficial to prevent leaks as a result of wear and tear. However, double seals are limited in that the maximum amount of pressure in operations utilizing a double seal design must be less than other seal configurations.
Tandem seals are frequently used in the petroleum industry and are very effective at preventing gas leaks even if seal failure occurs. When the primary seals fail, the secondary seal will take the full pressure of the system and prevent leakage. An intermediate labyrinth can also be used with a tandem seal. This prevents leaked gas from reaching the atmosphere by introducing a buffer gas in the labyrinth. This buffer gas is at a higher pressure than the other gas and thus prevents the movement of gas through the labyrinth.
The type of gas seal configuration needs to work in tandem with the seal support components. We will discuss these seal support components below.
Dry Gas Seal Support System Components
The dry gas seal support system needs several components to operate effectively. These components include the compressor, seal panel, and rotating seat. For each of these components, it is important that they are made out of corrosion-resistant materials. Further, the materials will need to be able to withstand the variation in temperature and pressure that occurs during operations. Each of these components are critical to operations.
The compressor is used to prevent gas leakage into the atmosphere and atmospheric gases into the system. It seals the rotating assembly in the stationary compressor case. The compressor should be selected based on the design, size, and chemicals used in operation.
The seal panel monitors the dry gas seal for gas leakage. It records data to indicate gas leakage and provides alarms to warn of gas seal failure. It also monitors the second seal to ensure that if a primary seal failure occurs, the gas will be prevented from leaking into the atmosphere. Design considerations need to be made for the seal panel and its configuration with the dry gas seal cartridge. The seal panel design must effectively deliver gas to the dry gas seal to prevent liquid from forming on the seal with changes to temperature and pressure.
The rotating seat generates aerodynamic life and creates gas film stiffness. It does this through the grooves of the rotating seat. The design and space constraints are important considerations when choosing a rotating seat.
The Benefits of a Seamlessly Integrated Dry Gas Seal Support System
A seal support system can properly regulate gasses used in processing while monitoring seal performance. However, to have an effective dry gas seal support system, the conditions (pressure, temperature, and chemicals used in operations) need to be fully assessed. Further, the type of dry gas seal needs to work with the components of the dry gas support system.
An expert in gas seals can help identify the components that are best suited for operations based on operational conditions and the type of dry gas seal.
For decades, Swagelok has been helping process and manufacturing companies in Northern California and Western Nevada to improve component reliability and through the guidance of dry gas seal and support system selection.
Our Field Engineers are available for consulting at your facility or online. We’ll work closely with you to understand your specific process requirements. With this understanding, we’ll design, fabricate, and thoroughly test your dry gas seal support systems following ISO 9001 standards. By partnering with Swagelok, you can ensure that your dry gas seal support system meets operational and safety standards.
About Malik Durojaiye | Field Engineer, Assembly Services
Malik Durojaiye began his Swagelok career in 2019 as a Custom Solutions Engineer in our Assembly Services group. Prior to Swagelok, Malik developed as a design engineer as well as a manufacturing engineer for 6 years serving Kentucky and California with Altec Industries; a leading provider of products and services to the electric utility, telecommunications, tree care, lights and signs, and contractor markets.