The API Standard for Dry Gas Seal: An Inclusive Guide

Precision-engineered dry gas seals prevent leakage in high-speed rotating equipment, including oil and gas, petrochemical, and power-generating compressors. Maintaining a slight separation allows non-contacting rotation and decreases friction and wear. Dry gas seal failures might cause major operational and safety menaces without rigid regulations. That's where API standards include reliable and secure dry gas seal performance criteria.

This article discusses the history and overview of API 692 and API 617, as well as key components, and installation/maintenance guidelines of API standards for dry gas seals.

History of the API Standard for Dry Gas Seals

API requirements for dry gas seals have upgraded industrial practices. API 617 initially covered general compressor specifications, including dry gas seals, but not details. However, API 692 was created in 2018 to address the particular requirements of dry gas sealing systems. It included important topics like seal gas filtration, booster needs, and system monitoring. For instance, API 692 requires 99.9% efficient filtering of impurities down to one micron for seal dependability.

Seal gas boosters maintain pressure differentials during compressor idle to stop process gas infiltration. Such improvements have strengthened sealing systems and lowered emissions.

Overview of API 692 and API 617 Standards for Dry Gas Seals

Introduction to API 692 of Dry Gas Seals

API Standard 692, "Dry Gas Sealing Systems for Axial, Centrifugal, and Rotary Screw Compressors and Expanders," was distributed in June 2018. It sets minimal specs for dry gas sealing systems in the petroleum, chemical, and gas sectors. Part 1 covers basic requirements, Part 2 dry gas sealing, Part 3 support systems, and Part 4 installation and commissioning. API 692 codifies industry best practices into a standard for better dry gas seal reliability.

Introduction to API 617 of Dry Gas Seals

API Standard 617, "Axial and Centrifugal Compressors and Expander Compressors," defines minimum specifications for such types of compressors in petroleum, chemical, and gas industries. It emphasizes compressor design, materials, and testing, but it also covers dry gas seals in high-speed situations where wet seals may not work. API 617 specifies dry gas seal selection and implementation for compressor reliability and performance. This foundational document complements API 692, which digs further into dry gas sealing systems.

Differences and Overlaps

Key Components of the API Standard for Dry Gas Seals

Seal Types and Configurations

API standards provide multiple dry gas seal designs for operations. When leakage control is less important, single seals have one set of sealing faces. Tandem seals have two seals in sequence to preclude leakage. Pressure fluctuations in the space between them indicate seal performance. Dual seals isolate the process fluid from the atmosphere and improve security in hazardous or toxic conditions with two sets of sealing faces separated by a pressurized barrier gas. The configuration used depends on process pressure, fluid properties, and safety.

Primary Components

Dry gas seal systems depend on many key parts. Seal faces of silicon carbide or tungsten carbide are hard and wear-resistant to handle high-speed rotating machinery. Keeping a positive pressure differential across seal faces by clean, dry gas (nitrogen) helps avoid process gas leakage. API 692 mandates that impurities be removed from gas to preserve seal integrity. Pressure and flow sensors are needed for real-time seal performance evaluation to identify pressure decreases and flow irregularities and inhibit seal failures.

API-Recommended Materials and Construction

API standards provide materials and constructing methods for better dry gas seal stability and life expectancy (around 10 years). Silicon carbide is used to make seal faces thanks to its wear resistance and thermal stability. Secondary sealing elements, including O-rings, are made of elastomers (fluoroelastomer or perfluoroelastomer) appropriate to the process fluid and operating temperatures. Preventing leakage while retaining face alignment demands precise engineering of the seal assembly to tolerate thermal expansion and mechanical loads.

Installation Guidelines for Dry Gas Seals per API Standards

• Confirm compatibility of seal materials with process fluids.
• Verify proper alignment of seal components.
• Keep specified clearances between rotating and stationary parts.
• Check the cleanliness of all seal components and housing.
• Apply appropriate lubrication to seal faces, if required.
• Install seals according to the manufacturer's torque specifications.
• Guarantee correct orientation of seal faces and components.
• Verify the uprightness of secondary sealing elements.
• Ratify installation of seal support systems, like piping and instrumentation.
• Conduct pressure testing of the seal assembly to detect leaks.
• Implement proper venting procedures to remove trapped gases.
• Make sure that all instrumentation is calibrated and functioning decorously.
• Document all installation procedures and parameters for future reference.

Maintenance Guidelines for Dry Gas Seals per API Standards

• Recurrently inspect and monitor seal performance.
• Follow manufacturer-recommended inspection and replacement schedules.
• Monitor pressure, temperature, and flow readings to detect performance degradation.
• Utilize condition-monitoring tools, including vibration analysis and leak detection.
• Periodically disassemble and inspect seal components.
• Assess and maintain seal faces to prevent wear and leaks.
• Replace O-rings or elastomeric seals to maintain elasticity and stop degradation.
• Check and replace seal support system components (filters) to avoid contamination.
• Inspect rotating and stationary components for wear and fatigue.
• Monitor and replace gaskets and bellows to elude mechanical stress-induced wear.
• Inspect labyrinth seals to avert contamination from external sources.
• Keep gas supply system components to guarantee correct pressure and flow.
• Confirm the cleanliness of the gas entering the seal to thwart contamination.
• Implement high-quality filtration systems to keep impurities out of the seal gas supply.

Dry Gas Seals from Lepu Seal

Lepu Seal engineers dry gas seals with high-precision, low-leakage technology to emit less than 10 ppm even at 400 pressures. Refined coatings make our seals durable for high-speed applications (up to 100 m/s). Due to our boosted secondary sealing system, frictional losses decrease, and operating life increases. Our customization approach satisfies different operating demands across chemical and maritime industries for a bespoke match for high-demand situations. In sensitive applications, our QC and CAD-driven design reinforce seal reliability.

Visit Lepu Seal to learn the dry gas solutions we provide.