Plug valve

Incorrect. That describes a ball valve.

Correct! This is the unique characteristic of a plug valve.

Incorrect. That describes a gate valve.

Incorrect. That describes a diaphragm valve.

Incorrect. While plug valves are low-maintenance, the tapered design is not the primary reason.

Correct! The tapered design ensures a tight fit, crucial for preventing leaks, especially at high pressures.

Incorrect. The tapered design does not directly influence flow rate.

Incorrect. The tapered design is not related to the valve's size.

Incorrect. Plug valves are known for their ability to withstand high pressures.

Correct! The simple quarter-turn operation makes plug valves fast and efficient to operate.

Incorrect. Plug valves are available in a variety of materials, including exotic alloys.

Incorrect. Plug valves are known for their low maintenance needs.

Incorrect. Plug valves are commonly used for pipeline flow control.

Incorrect. Plug valves are essential for wellhead operations.

Correct! While plug valves are versatile, mixing chemicals is typically handled by other valve types like mixing valves.

Incorrect. Plug valves are used in gas and oil separation processes.

Incorrect. The difference in cost is not the main factor.

Incorrect. Both types can handle high pressures depending on the specific design.

Correct! Lubricated valves use a lubricant to achieve a tight seal, while non-lubricated valves rely on a tight fit between the plug and body.

Incorrect. While some non-lubricated valves may be considered more environmentally friendly, this is not the main difference.

Here's a possible solution:

Key Factors to Consider:

1. Operating Pressure and Temperature: The well produces crude oil at 1000 psi and 250°F. The chosen plug valve must be rated to withstand these extreme conditions to ensure reliable operation and prevent failure.
2. Fluid Compatibility: Crude oil can be corrosive, so the valve material should be compatible with the fluid to prevent degradation and leaks.
3. Tight Shutoff: The valve needs to provide a tight seal to prevent leaks, which is crucial for safety and environmental protection at high pressures.
4. Maintenance Requirements: The valve should be designed for minimal maintenance to reduce downtime and operating costs in a challenging environment.

Suitable Plug Valve Types:

1. Lubricated Plug Valve: These valves are known for their tight shutoff, making them ideal for high-pressure applications. They are often designed to handle corrosive fluids, making them suitable for crude oil. Lubrication provides a smooth, leak-free seal and reduces wear and tear. However, they may require regular lubrication maintenance.

2. Non-Lubricated Plug Valve (with a high-performance, corrosion-resistant material): Non-lubricated valves are designed for applications where lubrication is undesirable or impractical. If the selected material is highly resistant to corrosion and wear, a non-lubricated valve might be a suitable option, minimizing maintenance requirements. However, ensuring the valve's compatibility with crude oil's corrosive properties is crucial.

Justification:

• Lubricated Plug Valve: The tight shutoff, high pressure rating, and compatibility with corrosive fluids make it a strong contender. However, the need for regular lubrication adds complexity.
• Non-Lubricated Plug Valve: The absence of lubrication offers simplicity and reduced maintenance. The chosen material must be robust enough to withstand the high pressure, temperature, and corrosive properties of crude oil.

Additional Considerations:

• Valve Size: The valve's size should match the flow rate of the oil well.
• Operating Environment: The wellhead's location and accessibility should be considered for ease of maintenance and operation.