Where Valves are Used – Oil and Gas Industry – Article

Where Valves are Used – Oil and Gas Industry

Historically, the oil and gas industry has presented equipment suppliers and production personnel with difficult and demanding operat­ing conditions. For valves, that has translated into an ever-increasing need for tougher, longer-lasting, bet­ter performing valves.

Demand for oil and gas grew tremendously during the industrial revolution and grew even further to fuel the development of western economies. This demand spurred the need for deeper wells, longer pipelines and lower production costs, which required drillers and refiners to select equipment more carefully. As produc­tion, transportation and processing technology advanced, equipment per­formance requirements became more and more stringent to support increasing operational efficiencies. Today, performance expectations are higher than ever because the variety of operating conditions has expanded, and the protection of personnel and the environment have been added to the list of requirements.

Valve service environments and operating conditions within the oil and gas indus­try are unique and extreme. From exceptionally high temperature (greater than 1,500 For 816 C) and high pressure (greater than 25,000 psig) to cryogenic (-150 F or -101 C) or cryogenic for LNG (-260 F or -162 C) and very low- pressure applications, valves must be engineered to perform dependably. In addition to this wide range of conditions, the remote locations of valve services also present unique challenges. Examples include deep sea valves operating 10,000 feet (3,048 meters) below the sea surface and pipeline valves exposed to the extreme tempera­tures found in a desert. Valves in these tough environments may stay open or closed for extended periods of time, yet they are expected to operate reliably even when they have not been cycled in many years.

Each segment of the oil and gas industry—upstream, midstream and down­stream—offers its own examples of extreme conditions for valves. In the upstream segment, valves control the flow of crude oil and natural gas from high-pressure injection systems to choke valves and blow-out preventers at the top of wells. Valve systems are asked to perform over the many years of a producing well’s life—a life that depends on different factors such as economies and new recovery techniques. New-found sources of oil and gas from tar sands and shale formations have added to the complexity of valve specifications because they require placing oil and gas into pipelines taken to processing facili­ties that can be many miles away.

The midstream segment—storage and transportation of oil and gas resources from remote sources such as the deepwater fields of the Gulf of Mexi­co or the frozen tundra of Alaska—has another unique set of conditions. Long pipelines require compressors along the way to keep the product moving, and valves are asked to protect equipment while offering minimal restriction to the flow. Extremely low temperatures are required for converting natural gas into natural gas liquids in preparation for transportation from isolated gas fields to gas-consuming markets. Cryogenic service demands that valves be made of materials for low temperatures and other special designs. Midstream solu­dons for loading/offloading terminals and storage tanks for oil and gas prod­ucts offer more opportunities for valve suppliers.

The third industry segment—down‑stream—brings challenges to find solu­tions for the refining process of crude oil, as well as the sale and distribution of both the refined product (i.e., gaso­line, fuel, asphalt, etc.) and natural gas. This sector is made up of industrial, retail and distribution businesses and is the segment that provides products such as heating and transportation fuels to consumers and businesses. Additionally, this segment feeds raw materials to a variety of petrochemical industries that use petroleum-based products to make plastics, fertilizers, pharmaceuticals and more. The valve requirements for the downstream market include higher pressure designs and metal-seating technology and metallurgies to accom­modate the temperatures at which mod­ern refineries operate

RELEVANT VALVES AND EQUIPMENT

Each of these industry segments faces unique and diverse environments that, in turn, create extreme operating condi­tions for valves and other flow control components. Because of the extreme temperatures and pressures, as well as the most remote and harshest environ­ments, the types of valves and materials for those valves for each segment vary considerably. There are very few valve suppliers that could provide a complete range of solutions, and most suppliers today specialize in one or two segments.

This is because of the complexity of requirements. For example, in the upstream segment, offshore exploration and production operations create extreme conditions, a situation made even more complex as the search for untapped oil and gas fields Continues into deeper and deeper waters. In these applications, valve strength and per­formance is critical because of the dam­age that leakage could cause to the seas and their fragile ecosystems. Standard options for this segment include gate valves produced with higher alloy mate­rials and, on occasion, ball valves. They are used for a variety of reasons includ­ing resistance to corrosion and damage caused by constant exposure to raw sea water. In addition, these valves offer low-depth sensitivity and have proven over time to perform well in this high- pressure, remote environment

In midstream applications that involve transportation of oil and gas, isolation valves play an important role in pipelines. There are primarily two types of pipelines for the energy indus­try—those for oil and those for natural gas. Within each group are subsets that serve specific applications. For example, oil pipelines gather crude oil from a production site and transport the unre­fined oil to refineries. Once refined, additional pipeline networks distribute the refined oil products throughout the world. Natural gas, on the other hand, is typically transported directly from the source to the end user; however, it also includes the cryogenic service that com­presses gas into liquid for economical transport to distant markets

As in the upstream segment, the most common valve solutions for the midstream market include full-port gate and ball valves in materials chosen specifically for the service. For example, nozzle check valves with low-pressure drops and rapid responses to changes in the flow are a critical component to compressor stations, which energize the media for long pipelines. Some major factors when selecting a pipeline valve include the pipeline size, the media that will run through the pipelines and the environment in which the pipeline will operate. Shut-off valves must be full-port designs, not only to minimize pres­sure loss, but also to accommodate pipeline inspection gauges (nicknamed “pigs”), which are used to inspect and clean the inside of pipes or to separate different media as it flows through the line. Regardless of valve style, depend­ability is critical. Although these valves may only rarely be cycled, they may be needed for pipeline flow diversion, shut­off or isolation performance so reliabili­ty is vital. For example, if a pipeline rupture occurred, isolation valves would play a significant role in minimizing environmental damage by shutting off the flow.

Within the downstream segment, there are many harsh environments that require a variety of design solutions. In particular, within refining, applications such as delayed coking present chal­lenges for valve operational integrity. Delayed coking is a heat-intensive process in which heavyweight oil under goes a thermal cracking process that produces the gas oil and petroleum coke. During this process, valves are subject to temperatures of more than 900° F (483° C). Adding to the chal­lenge is the fact that delayed coking process valves are cycled every 12 to 16 hours (for a typical two-drum base cycle). Failure of one valve can shut the entire refinery down, which could cost untold millions of dollars in operating revenues. High-temperature applica­tions such as delayed coking place a sig­nificant amount of thermal stress On all valve components. Added to the temper­ature extremes, coking fines are highly abrasive, which impacts plug/disc and body seating surfaces, as well as the gaskets and stem packing.

To support the operational integrity of this application, valves can be equipped with many special characteris­tics, including heat-dissipating fins, materials designed for high-temperature functionality and remotely-controlled operating systems.

SPECIFIC VALVES FOR THE INDUSTRY

Refinery segments that use valves include atmospheric distillation, vacuum distilla­tion, hydro treating, catalytic reforming, fluidized catalytic cracking, alkylation, hydro cracking, delayed coking, sulfur recovery, visbreaking, gasification, Cube treating and gas plants. The ideal types of valves for these applications vary widely; but, in general, they include multi-torn valves, HF alkylation valves, quarter-turn valves and flow reversal pro­tection valves, to name a few.

Multi-turn valves, such as bolted bonnet gate and globe valves, are generally offered in materials developed to accommodate a variety of flow media. These valves feature a body cast with straight-through ports to minimize turbulence, erosion and pressure drop. Additionally, these valves can be outfit­ted with seat rings seal-welded to elimi­nate potential leak paths behind the rings. Specially developed materials are used in more erosive or higher tempera­ture services.

HF alkylation valves are available in several designs, such as gate, globe, Check or sleeved plug valves. These valves typically offer benefits such as leak-detection options, low-corrosion materials and sealing systems that mini­mize the risk of potential emissions.

Quarter-turn valves include by and large the most versatile selection of valves. This group of valves is com­prised of the metal-seated plug, metal- seated ball, triple offset, soft-seated ball, sleeved plug, high-performance butterfly and others chosen for their special quali­ties. For example, the metal-seated plug valve is renowned for its ability to per­form in hot, dirty and severe refining applications, including delayed coking, ethylene cracking, fluidized catalytic cracking and asphalt production. One design uses the seating advantages of a wedge gate valve and the simplicity of quarter-turn operation. This design pro­vides protection from erosion damage, solids buildup on the sealing surfaces and in cavities, and residual freeze up, which can prevent operation and cause leakage from packing wear.

HSE REQUIREMENTS

Health, safety and environmental (HSE) requirements are critical fac­tors in the oil and gas industry, and key players must meet these HSE stan­dards to maintain the license to oper­ate. These requirements can be affect­ed by the equipment used within a given facility, including valves, and money lost from unplanned shutdowns or costly repairs are a significant threat to the industry.

Because of this, an important aspect of the industry includes acknowledgement of available certifi­cations and quality standards. The most relevant organizations in the industry include the Environmental Protection Agency, International Standardization Organization, Ameri­can Society of Mechanical Engineers and American Petroleum Institute. Examples of what these bodies produce in the oil and gas industries include detailed specifications for valve construction, emissions testing and technical standards for safety.

FAVORABLE MARKET TRENDS

Market trends are particularly relevant in the oil and gas industry because son* experts identify capital investments in this industry as a predictor of global valve market success. In North America, oil and gas investments favor expansion of current facilities, including throughput improvements, sulfur removal and increased spending on maintenance.

According to the Energy Information Administration (EIA), the International Energy Agency and the Organization of the Petroleum Exporting Countries, three of the most respected oil- and gas-related Organizations worldwide, crude oil demand is rising again after several years of negative growth. These Organizations predict this rate of growth will increase over the next two years, which will inevitably lead to consumption rates that reach above pre-recession usage.

For natural gas, on the other hand, the short-term demand and consumption are projected to decrease minimally in 2011. This information is based on fore­casted weather trends and the economy as a whole, among other factors. Howev­er, the E IA also predicts that in 2012, natural gas is expected to rebound from the slight decline at a rate of approxi­mately 1.5% growth over 2011.

CONCLUSION

The oil and gas industry provides valve manufacturers extreme application chal­lenges brought about because of harsh environments in discovery, transporting and refining. Control, regulating, shut-off and backflow prevention services are required in every piping system of the industry. Valve manufacturers have responded with specialized valve designs, materials and machining procedures to meet the industry’s critical specifications. With a rebound expected for the mar­kets, valve producers in the oil and gas field have some reason to be excited about the future.

Source: Valve Magazine

On 八月 5th, 2011, posted in: Industry News by Tags: , ,