In the gas industry, valves are crucial equipment used for controlling the transmission, distribution, pressure regulation, and safety assurance of gases. Due to the unique operational conditions and safety requirements of the gas industry, valves must possess high reliability, resistance to high pressure, corrosion resistance, and excellent sealing properties. Below are specific applications and special requirements of valves in the gas industry:
Application Scenarios
1. Urban Gas Distribution Network:
- Control the transmission and distribution of natural gas in urban pipelines.
- Use valves with high sealing and corrosion resistance.
2. Gas Pressure Regulation Stations:
- Control gas pressure regulation and flow control.
- Require high-precision pressure regulating valves and quick-acting shut-off valves.
3. Gas Storage:
- Control the storage and transmission of liquefied natural gas (LNG) or compressed natural gas (CNG).
- Use valves that are resistant to low temperatures and high pressures.
4. Gas Transmission and Distribution Systems:
- Control the flow and pressure of gas in transmission and distribution systems.
- Require valves with high sealing and corrosion resistance.
5. Gas Application Equipment:
- Control gas flow in gas boilers, gas stoves, and industrial gas equipment.
- Use valves with high safety and sealing performance.
Special Requirements
1. High Pressure Resistance:
- Valves must withstand pressures up to several hundred psi (pounds per square inch) during gas transmission and storage.
- Materials typically include high-strength alloy steel or stainless steel.
2. Low Temperature Resistance:
- Especially in LNG systems, valves must endure temperatures as low as -162°C.
- Materials need to maintain low-temperature toughness, such as stainless steel and low-temperature steel.
3. High Sealing Performance:
- Ensure no leakage under high pressure and temperature conditions to prevent gas leaks and potential safety incidents.
- Employ metal seals or composite sealing materials for effective sealing under extreme conditions.
4. Fire and Explosion Proof:
- Valves should be designed to be fire and explosion proof to ensure safety in flammable and explosive environments.
- Certified through fire safety testing standards like API (American Petroleum Institute).
5. Corrosion Resistance:
- Valves must resist corrosion from components in gas like hydrogen sulfide.
- Use materials such as stainless steel, nickel-based alloys, or fluorine-lined materials.
Typical Valve Types
1. Ball Valves:
- Suitable for quick opening and closing requiring tight shut-off.
- Full bore design reduces fluid resistance, suitable for urban gas distribution networks and gas transmission systems.
2. Butterfly Valves:
- Used for flow control in large-diameter pipelines.
- Simple structure, lightweight, suitable for pressure regulation stations and storage systems.
3. Globe Valves:
- Suitable for applications requiring precise flow control.
- Simple structure with superior sealing performance, suitable for gas pressure regulation and application equipment.
4. Check Valves:
- Prevent reverse flow to protect equipment safety.
- Used in various process pipeline systems.
5. Safety Valves:
- Prevent system overpressure, protecting equipment and personnel safety.
- Used in high-pressure vessels and pipeline systems.
6. Pressure Regulating Valves:
- Used in gas pressure regulation stations to ensure stable gas pressure.
- High precision, quick response to ensure downstream gas supply safety.
Maintenance and Operation Considerations
1. Regular Inspection and Maintenance:
- Periodically inspect valve sealing and operational performance, promptly replace worn or damaged components.
- Clean valves internally and externally to prevent deposits and corrosion.
2. Lubrication:
- Regularly apply appropriate lubricants to valves requiring lubrication for smooth operation.
- Use lubricants suitable for high temperature and high pressure to prevent lubricant failure.
3. Fastener Inspection:
- Periodically check valve fasteners to ensure tightness and prevent leaks.
4. Operational Procedures:
- Operators must strictly adhere to operational procedures to avoid excessive force or rapid operations that may damage valves.
- Conduct training on valve performance and operating procedures to ensure safe and effective use.
5. Emergency Handling:
- Develop and familiarize with emergency response plans to promptly address emergencies such as valve leaks or failures.
Typical Case Studies
1. Urban Gas Distribution Network Ball Valves:
- Ball valves used in urban gas distribution networks require high sealing and corrosion resistance, typically made from stainless steel or nickel-based alloy materials.
2. LNG Storage System Butterfly Valves:
- Butterfly valves used in LNG storage systems require high sealing and low-temperature resistance, with valve bodies and discs made from materials resistant to low temperatures.
3. Gas Pressure Regulation Station Pressure Regulating Valves:
- Pressure regulating valves used in gas pressure regulation stations require high precision and quick response capabilities to ensure stable downstream gas supply.
By selecting appropriate valve types and materials and conducting regular maintenance and inspections, valves in the gas industry can operate stably in high-pressure, low-temperature, corrosive, and potentially hazardous environments, thereby improving production efficiency and equipment safety.