Petroleum Valve in the Oil and Natural Gas Field

Each market segment in the oil and gas industry faces a unique and diverse environment, which creates extreme operating conditions for valves and other flow control components. Due to extreme temperatures and pressures, as well as the most remote and harshest environments, valve types and valve materials vary greatly in each market segment. Few petroleum valve suppliers can provide a complete solution, and today most suppliers focus on one or two areas.

For example, in the upstream part, offshore exploration and production operations have created extreme natural conditions. As the exploration of undeveloped oil and gas fields continues into deeper waters, the situation becomes more complicated. In these applications, the strength and performance of the petroleum valve are critical, as leakage may cause damage to the ocean and its fragile ecosystem. Standard options in this segment include gate valves made with higher alloy materials and sometimes ball valves. They are used for a variety of reasons, including corrosion resistance and damage caused by continuous exposure to raw seawater. In addition, these valves have low depth sensitivity and have proven to perform well in this high-pressure, remote environment over time.

In midstream applications involving oil and gas transportation, isolation petroleum valves play an important role in pipelines. There are two main types of pipelines in the energy industry-oil pipelines and natural gas pipelines. Within each group, there is a subset that serves a specific application. For example, oil pipelines collect crude oil from production sites and transport unrefined oil to refineries. Once refined, an additional pipeline network distributes refined petroleum products to all parts of the world. On the other hand, natural gas is usually transported directly from the source to the end-user.

As in the upstream sector, the most common valve solutions in the midstream market include full-port gate valves and ball valves, which use specialized materials. For example, the nozzle check valve with low-pressure drop and rapid response to flow changes is a key component of the compressor station, providing energy for the medium in the long pipeline. Some of the main factors when choosing a petroleum pipeline valve include the size of the pipeline, the medium flowing through the pipeline, and the environment in which the pipeline operates. The shut-off valve must be a full-port design, which can not only minimize pressure loss but also accommodate pipeline inspection instruments (nicknamed “pigs”), which are used to inspect and clean the interior of the pipeline or separate different media flow lines. Regardless of the valve type, reliability is paramount. Although these petroleum valves may rarely be recycled, they may require pipeline flow diversion, shut-off, or isolation performance, so reliability is critical. For example, if a pipe rupture occurs, the isolation valve will play an important role in minimizing environmental damage by shutting off the water flow.

In the downstream part, there are many harsh environments that require various design solutions. Especially in the oil refining field, applications such as delayed coking pose a challenge to the integrity of the valve operation. Delayed coking is a heat-intensive process in which heavy oil undergoes a thermal cracking process to produce gas oil and petroleum coke. During this process, the petroleum valve will withstand temperatures exceeding 900° F (483° C). Adding to the challenge is the delayed coking process valve cycle every 12 to 16 hours (for a typical two-drum base cycle). The failure of a single petroleum valve can shut down an entire refinery, which can result in millions of dollars in lost operating income. High-temperature applications such as delayed coking can cause a lot of thermal stress on all petroleum valve components. Coupled with extreme temperatures, the coking powder is highly abrasive, which will affect the petroleum valve plug/disc and valve body seat surface, as well as gaskets and stem packing.

To support the operational integrity of the application, the petroleum valve can be equipped with many special features, including cooling fins, materials designed for high-temperature functions, and remotely controlled operating systems.

This article introduces the different types of  oil and gas valves used in the petrochemical industry for any of the following applications:

1. Petroleum valves are responsible for starting/stopping the flow of fluids (including hydrocarbons, oil and natural gas, steam, water, acids and other fluids) through pipelines (such as gate valves, ball valves, butterfly valves, knife gate valves or plug valves);
2. Many Petroleum valves can freely adjust the fluid flow through the pipeline (for example: stop valve);
3. Oil and gas valves can control the flow of fluid in the pipeline (for example: control valves);
4. Petroleum valves can change the direction of fluid flow (such as three-way ball valves);
5. Petroleum valves can adjust the pressure of fluids in the flow process (such as pressure reducing valves);
6. Petroleum valves can protect pipelines or equipment (pumps, motors, tanks) from overpressure (safety or pressure relief) or back pressure (for example, check valves);
7. Petroleum valves can also filter debris flowing through the pipeline to protect equipment that may be damaged by solid components (y and basket filters).

The Petroleum valves used in the oil and gas industry are generally assembled from multiple mechanical parts. The key components are the valve body (housing), valve trim (combination of replaceable wetted parts), valve stem, valve cover, and action Mechanism (manual lever, gear or actuator). Due to the particularity of the oil and gas industry, all industrial valves must be made of corrosion-resistant, high-temperature, and high-pressure materials.

Petroleum valves used in the oil and gas industry and for piping applications can be classified in multiple ways:

Disc type

The following disc types are mainly used in the oil and gas industry:

1. Linear motion: gate valve, globe valve, diaphragm valve, pinch valve and check valve.
2. Rotational movement: butterfly valve, ball valve, plug valve, eccentric valve and swing check valve.
3. Quarter turn: A device that requires about a quarter-turn of movement, from 0 to 90° of the valve stem, to move from a fully closed position to a fully open position, and vice versa.

If we classify the petroleum valves used in oil and natural gas according to the driving method, we can classify them in the following ways:

1. Manual valve: The valve is manually operated by levers, wheels and/or gears;
2. Automatic valve: The valve is driven by an electromechanical device called an actuator, which can be electric, pneumatic, hydraulic and oil pressure.

According to the valve design, it can be classified into the following categories:

1. Gate valve: This type is most commonly used in oil and gas pipelines. But gate valves cannot be used for throttling applications, that is, to adjust fluid flow. If you want to adjust the flow in oil and gas pipelines, using a globe valve or a ball valve is the best choice at this time.
2. Globe valve: This type of valve is used to throttle (regulate) fluid flow. The shut-off valve can also close the flow.
3. Check valve: This type of valve is used to avoid backflow in oil and natural gas pipeline systems or pipelines, thereby damaging downstream equipment, such as pumps, compressors, etc. When the fluid pressure is sufficient, it opens the valve; when it returns to the design pressure (reverse flow), it closes the valve-preventing unwanted flow.
4. Butterfly valve: This is a multifunctional, cost-effective valve used to regulate or open/close the flow of fluid. The butterfly valve has a concentric or eccentric design (double/three), compact in appearance, and because of its simpler structure and cost, it is more and more competitive than ball valves.
5. Pinch valve: This is a linear motion valve that can be used for throttling and closing applications in pipeline applications that handle solid materials, drilling fluids and mud. The pinch valve uses a pinch tube to adjust the flow.
6. Safety valve: The safety valve can also be called a pressure relief valve, which is mainly used for offshore drilling platforms and oil and gas pipelines. Essentially, the safety valve releases the pressure when the set value is exceeded.
7. Control valve: This type of valve is mainly used in some refining and chemical enterprises.

In addition to the above petroleum valves that are common in the middle and upper reaches of the oil and gas industry, the use of valves also includes downstream industries such as refineries and natural gas plants. Generally speaking, they include multi-stop valves, HF alkylation valves, quarter-turn valves, and reverse flow protection valves.

1. Multi-turn valves, such as bolted bonnet gate valves and globe valves, usually use materials developed to adapt to various flowing media. These valves use body castings with straight-through ports to minimize turbulence, erosion, and pressure drop. In addition, these valves can be equipped with seal-welded seat rings to eliminate potential leak paths behind the seat. Specially developed materials are used for more corrosive or higher temperature services.
2. HF alkylation valve has many designs, such as gate valve, globe valve, check valve or sleeve plug valve. These valves usually have the advantages of leak detection options, low-corrosion materials, and sealing systems to minimize the risk of potential emissions.
3. The right-angle rotary valve basically includes the most versatile valve selection. This group of valves includes metal seat valve core, metal seat ball valve, triple eccentric valve, soft seat valve, sleeve valve core, high-performance butterfly valve and other valves selected for their special performance. For example, metal-sealed plug valves are known for their performance in high-temperature, dirty, and harsh oil refining applications, including delayed coking, ethylene cracking, fluid catalytic cracking, and asphalt production. One design takes advantage of the seat advantage of the wedge gate valve and the simplicity of the right-angle turn operation. This design prevents corrosion damage, solid accumulation in the sealing surfaces and cavities, and residual freezing, which can prevent operation and cause packing to wear and leak.

Because the oil and gas industry is a very dangerous industry, the petroleum valves used in this industry must meet a number of safety standards. ASME Valve Standard B16.34 is a globally recognized standard for the design, manufacture and testing of valves used in the oil and gas industry.

The petroleum valve’s ASME B16.34 standard mainly includes the following:

1. The  petroleum valve body and shell materials used in the oil and gas industry comply with ASME and ASTM material chemistry and strength standards;
2. The main body and shell materials of petroleum valves must be heat treated to ensure proper grain structure, corrosion resistance and hardness.
3. The wall thickness of the petroleum valve body and other pressure-bearing parts meets the minimum value of each pressure level specified by ASME B16.34.
4. The end connection of NPT and SW conforms to ASME B1.20.1 or ASME B16.11.
5. The petroleum valve stem is loaded inside and has a blowout prevention function.
6. All bolt connections are ASTM grade, and the maximum applied stress is controlled by B16.34.
7. Each petroleum valve must undergo a shell test for a specific test duration at 1.5 times the rated pressure.
8. Each oil and gas valve undergoes a two-way valve seat leakage test within a specific test duration.
9. Each petroleum valve is marked with construction materials, operating restrictions and the manufacturer’s name.

In addition to the above compliance standards, Health, safety and environmental (HSE) requirements are key factors in the oil and gas industry, and a qualified petroleum valve manufacturer must meet these HSE standards in order to maintain operating permits. These requirements may be affected by the equipment (including valves) used in a given facility, and the financial losses caused by unplanned downtime or expensive repairs pose a major threat to the industry.

Therefore, an important aspect of the industry includes the recognition of available certifications and quality standards. The most relevant organizations in the industry include the Environmental Protection Agency, the International Organization for Standardization, the American Society of Mechanical Engineers, and the American Petroleum Institute. Examples of products produced by these agencies in the oil and gas industry include detailed specifications for valve structures, emission testing, and safety technical standards.

Petroleum valve manufacturer used in the oil and gas industry need to know the following information to supply the right device:

1. Valve type.
2. Bore size in NPS or DN.
3. Petroleum valve pressure rating (class range from 150# to 4500#).
4. Specification (example API 6D, API 600, API 602, etc).
5. Body and trim materials (at least).
6. Required end connection (flanged, threaded, butt weld, lug and others).
7. Fluid in the pipeline (>oil, gas, water, steam, solids).
8. Working temperature and pressure.
9. Quantity.
10. Delivery time.
11. Origin restrictions (Chinese and Indian origins allowed or not).
12. Each petroleum manufacturer has its own valve ordering sheets that map the valve configuration parameters that the user has to consider.