“Sub-arctic climates experience temperatures from 100° F (38° C) in the summer to –60° F (–51° C) in the winter. While there is nothing spectacular about the high end of the range, the low end impacts the functionality of pneumatic actuators”
You may ask, how exactly does the temperature impact the pneumatic actuators that are in the fields right now? There are a few things you have to consider.
First, the actuator housing is steel, thus the housing becomes brittle. This does not necessarily mean it becomes weaker but a sudden impact or an imperfection can result in a sudden fracture at these temperatures because the temperature is below the brittle transition temperature of steel.
Secondly, the “precipitation-hardened shaft material has also become brittle and may fracture given an impact load. If, for example, the driven valve resists opening and then breaks free, the resulting sudden impact may cause the actuator shaft to fail.”
There are many solutions to these issues, but the best would be to call your actuator mfg to discuss how to avoid any fractures caused by these temperatures. Just like the manufacture should know what to do, the users of the actuators should know what to do as well. If you are not able to get in contact with your manufacturer, here are a few steps you can take:
“First, and most obvious, users should shelter the actuator from weather extremes where possible. Second, users must assure a dry air supply, at least 15° F (–9° C) below the lowest temperature that may be experienced since ice plays havoc with air flow and mechanical motion. Finally, users should assess the recommended actuator and whether all possible precautions have been incorporated by the supplier.”
Clearly, pneumatic actuators can perform their intended functions despite having to operate in extreme temperatures. However, they need to be designed and manufactured properly, and users need to take responsibility to keep them functioning correctly.
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Pipeline Ball Valves are manufactured and tested in accordance with the requirements of API 6D, and are designed not to rely on lubricant to ensure that they seal.
During manufacture and factory testing, the use of lubricants and/or sealants is prohibited. This is to prevent masking of any defects in the new valve.
Installation and commissioning into a pipeline is an interventive engineering process, making use of hot and cold working techniques relying on mechanical tooling. As a result it is inevitable that between valve installation and commissioning, an amount of foreign debris will enter the valve (i.e. sand / dirt / swarf / weld slag). This is a natural result of the manufacturing process that cannot be avoided.
Once installed the valve is usually cycled during the testing of its gearbox or actuator, and again during hydrostatic testing of the pipeline.
These activities create tiny scratches on the polished ball surface where the debris present in the line wears on the ball and seat during the cycling of the valve.
In time, this reduces the valves ability to provide an adequate seal, as these tiny scratches begin to cause minor leak paths. All fluid and gas flows contain an element of contaminant which contributes to this effect over the life of the valve.
Minor leak paths that seal at low pressure become obvious when using the valve to isolate high pressure gas. Seating material is often softer than the ball itself in order to provide a pliable material which takes up minor leak paths, but at higher pressures the gas compresses the seats and they become less pliable meaning that the minor leak paths become more significant at higher pressures.
This type of damage mechanism can also be said to be true for gate and plug valves, as gate and plug surfaces are also susceptible to the similar damage. In fact any sealing surface subject to mechanical friction is susceptible to the damage mechanism described above.
Lubricants, lubricant-sealants and emergency-sealants
Lubricants help clean valve internals, and reduce operating torque. Valvecare use a light lubricant called Equa-Lube Eighty from Sealweld immediately after hydrostatic testing of valve, to purge all test water from seat pockets where corrosion normally occurs. The advantage of this is that it removes as much debris as possible from the internal mechanism of the valve, thus reducing the chance for wear. Lubrication also reduces the friction between the wearing surfaces. Of course, new contaminant can be introduced at any time via the flow in the pipeline.
Lubricant-Sealants help to preserve seat sealing effectiveness, and to seal worn valves with minor leakage problems. Valvecare use a lubricant-sealant called Total-Lube # 911 from Sealweld, this has been proven to seal minor scratches to sealing surfaces and shallow corrosion pits, as well as small nicks and cuts on soft seals.
For valves with sealing surface scoring, this is an effective way to achieve a bubble tight seal on a valve that would otherwise fail a leak test. Use of lubricant-sealants can delay or prevent the need for costly overhaul of a worn valve.
Emergency Sealants provide an effective temporary means of creating of leak tight seal, even on valves with severe leakage problems. Valve sealing plays an important role, when performing pipeline repair, modification or renewal work, as often the costs of shutting down, evacuating, draining, and excavating pipeline equipment are typically many times more than just the cost of a new valve. Valvecare use a Valve Sealant called Ball Valve Sealant #5050 from Sealweld, containing particles of PTFE, and is capable of sealing relatively large scratches to sealing surfaces.
Lubrication is introduced into the valve, using the seat injection fittings. Valves that do not have seat injections fittings can usually be retrofitted to include these. Specialist valve maintenance companies, such as Valvecare, can advise you on specifics for individual valves.
Seat lubrication, is a proven means of cleaning foreign debris from valve seats, and done properly as part of a scheduled valve maintenance programme, stops debris from getting there in the first place. This practice significantly reduces damage suffered during installation, commissioning and normal cycling operation, extending the service life of the valve dramatically. The costs associated with a scheduled maintenance program including lubrication are considerably lower than a full overhaul or replacement of the valve itself.
Lubricating your valves gives the following operational advantages:
- Cleans their seats of potentially damaging particles (Sand / Dirt / Swarf / weld slag)
- Stops debris from getting stuck between seats if administered before pigging pipeline
- Prevents and removes stiction (Torque to operate reduced / less strain on stem and actuator)
- Preserves the life of their seals, and components against mechanical and corrosion damage
These advantages reduce operational cost and should therefore form part of your planned valve maintenance programme.
Emergency Sealing involves the introduction of heavy sealant, through the valve seat injection fittings, to achieve a temporary seal. Valves that do not have seat injections fittings can usually be retrofitted to include these. Specialist valve maintenance companies, such as Valvecare, can advise you on specifics for individual valves.
Emergency Sealing your valves:
Provides an temporary bubble tight seal, even on valves with severe leakage problems
Has significant cost savings, when compared to alternatives
Saves time, with lead times for some replacement pipeline valves taking several months
The Lubrication, lubricant-Sealant and Emergency Sealant process involves the use of specialist equipment, capable of pumping a range of lubrication and sealant types safely at pressures of 10,000–15,000 psi. It is recommended that trained valve service engineers, proficient in the safe use of sealant guns and pumps, carry out this procedure.
Lubrication and sealing becomes more critical in applications such as Natural Gas, Production Wellheads, Gathering Systems, Gas processing Plants, Pipelines, Gas Storage Facilities and Gas Distribution Systems. Applications like these are more likely to cause damage to the critical sealing surfaces of valves, due to the lack of lubrication present in dry gas, and the presence of sand and debris in production wellheads. As part of a valve maintenance programme, preventative valve maintenance helps minimises the adverse effects of these services, increasing the service life of your valves.
For increased valve service life, the presence of an emergency seat sealant injection feature is an important consideration when procuring pipeline valve stock.
Equally as important is the choice of injection fittings and/or adaptors that are installed on the valve. Sealant injection fittings feature a means of passing sealant or lubricant into the valve, and incorporate a high pressure metal seated check valve. As a safety precaution, Valvecare do not endorse the use of carbon steel, crimped style injection fittings. As standard, we only recommend the use quality stainless steel injection fittings incorporating a threaded spring retaining cage, in order to minimise the risk of dangerous fitting failure.
Valve lubrication and sealing is an essential part of an effectively managed valve maintenance programme. Once installed and lubricated, a regular documented lubrication schedule should be established for all critical valves. Valvecare specialise in a supplying a total management programme for your valves, with a focus on the criticality of valves in relation to impact on safety elements and production, maintenance routines, spares holding, valve tracking and selection procedures. This type of valve management programme is a highly effective way of optimising reliability and safety whilst minimising cost and downtime.
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Editor’s Note: This is the fourth in a multi-part series examining the fundamentals behind the structural transformation of the U.S. oil markets and the downstream logistics challenges that are resulting. The third installment covered the “disconnect” between inland crudes priced off Cushing crude values when the North American oil hub is flush with crude in storage. (Image Source: CN)
As geopolitical turmoil drives crude prices skyward and lifts retail gasoline to US$4.89 per gallon (/gal) in cities like Los Angeles, it’s anything but business as usual in the U.S. oil patch.
Inland producers who are left in the dust amid triple-digit waterborne crude prices on most every U.S. coast are pioneering inventive downstream logistics to ship crude at low cost to higher-priced markets – thereby avoiding the disconnect in the wild west of North America’s oil industry.
Nearly every multimodal logistics opportunity short of yesteryear’s Pony Express and today’s Federal Express is being considered to cost-effectively ship crude oil to profit from high-price spreads between landlocked and waterborne crudes.
In intra-day trading on March 2, a remarkable spread was logged as the West Canadian Select (WCS) grade saw discount pricing around $80.00 per barrel (/ bbl), while both Heavy Louisiana Sweet and Light Louisiana Sweet (HLS and LLS) crudes on the Gulf Coast traded at more than $122.00/bbl.
That astounding discount of more than $40.00/bbl represents 50% of the then current WCS value. The basis differential can partly be explained by crude quality, but these theoretically, wide-open arbitrage opportunities attract pioneering innovators like the land rush days of old.
Furthermore, the $19.70/bbl discount to LLS prices that day for 38 million barrels of crude stored inland at Cushing at the time represented $750 million in dollar terms.
In the void left by insufficient pipeline takeaway capacity, tankers are stepping in to ship crude via rail and inland waterways away from the heavily utilized and smaller Mid-Continent refining fleet toward a Gulf Coast refining fleet twice its size.
Canadian Railway Company Rides the Rails to the Rescue?
Canadian National Railway Co. (CN), based in Montreal, Quebec, has pioneered and trademarked, PipelineOnRail – described as an “economically sound, surprisingly fast way to ship crude oil products within Alberta to the rest of Canada, the U.S. Midwest, the Gulf coast and other export markets.”
The plan seeks to use its extensive North American rail system that already traverses the Canadian continent on an East-West axis to tank crude south along its interconnected rail spine spanning the U.S. down the Mississippi River valley all the way to and around the U.S. Gulf Coast.
On March 1, Hart Energy contacted CN’s Kelli Svendsen, senior manager of regional public and government affairs, and learned that “CN has been testing concepts to move crude (heavy, light, and pure bitumen) from areas in Western Canada to various markets in the U.S.”
Svendsen said two areas of Canada are already exporting crude oil to the U.S: “CN has moved pure bitumen from Fort McMurray to U.S. markets,” and “from the Bakken reserves in Saskatchewan (Canada) to the U.S.”
The Bakken effort began recently with shipments “in October 2010.” Svendsen said, adding that “CN is optimistic that rail will play an increasing role in the transport of crude moving forward.”
EnSys Study Documents Crude-by-Rail Potential
EnSys Energy noted in a December 2010 North American crude logistics assessment that “CN Rail currently imports condensate, for blending with oil-sands bitumen to make DilBit (a.k.a. diluted bitumen)” from the Kitimat Port on Canada’s west coast.
According to EnSys, the “PipelineOnRail … avoids the large, fixed investments associated with major pipelines.” EnSys also noted that CN indicates potential capacity to move “as many as 200,000 b/d or more.”
EnSys said the study did not allow for the expansion of the PipelineOnRail capacity in any scenario, because tariffs for rail are generally not considered attractive relative to pipelines.
“However, during a period of constrained pipeline capacity, the PipelineOnRail could compete as an alternative,” the assessment reads.
Pioneers on the U.S. Side of the Border
The Bakken petroleum that CN is shipping originates from a producing region that extends into the U.S. states of North Dakota and Montana. Drillers in North Dakota produce the area’s greatest share of petroleum using unconventional hydraulic fracturing and horizontal drilling techniques.
Justin Kringstad, director of the North Dakota Pipeline Authority (PA), wrote in a September 10, 2010, release: “Because of our distance to market, regional producers have always absorbed a per-barrel discount on production.” Yet he noted that recent increases in rail and pipeline “takeaway capacity has pared that discount down substantially.”
Kringstad tabulated new capacity for crude oil shipments from several takeaway projects, including new rail-loading terminals in the area. These include EOG Resource’s 65,000-b/d rail facility in Stanley, N.D., which began rail tanker shipments to Cushing, Okla., in December 2009.
Hart contacted EOG spokesperson K. Leonard on March 1, who shared that “EOG is currently utilizing five trains, with plans to add a sixth in the future.” Leonard said EOG leases the rail tankers it uses to ship crude.
“The company typically loads one train daily and regularly hauls 68,000 gross barrels of crude per train,” Leonard said, adding that “Each train has approximately 100 cars.”
North Dakota PA’s Kringstad further noted in his release that Hess Corp. is readying a $48-million, 60,000 b/d rail facility in Tioga, N.D., for an early-2012 start-up. His post also said that Dakota Transport Solutions began shipping crude from New Town, N.D., to St. James, La., in August 2010. Kringstad said that facility reportedly had the capacity to transport 20,000 b/d by the end of 2010.
Kringstad also noted that smaller rail facilities operate with an estimated combined capacity of 30,000 b/d and include North Dakota locations in Minot, Dore, Donnybrook and Stampede.
Rangeland Energy LLC a New Pioneer
Rangeland Energy LLC (Rangeland), based in Sugar Land, Texas, has also announced plans that would enable Bakken producers to ship crude by rail tanker to the U.S. Gulf Coast.
On March 1, Hart spoke with Chris Keene, Rangeland president and CEO, and learned the company is developing the “COLT” rail terminal hub or connector to ship 100 rail tankers daily (60,000 b/d) of Bakken crude via the BNSF Railway Company to points including the Gulf Coast.
Keene said his company was formed in 2009 and noted: “It’s a huge opportunity, and I think our facility that we are building will be extremely valuable to the industry. It’s been great.”
“There are new rail tank cars being built as we speak. As fast as they can build them, they are being leased. In fact, they are being leased before they build them. Tank car makers, Keene said, have a huge backlog at present – driven by this trend.
Although Keene would not name names, Hart learned that Dallas-based Trinity Industries, Inc., and Oregon-based The Greenbriar Companies, manufacture multi-modal tankers for rail, barge and/or land transport. A review of company disclosures suggested a confirmation of strong backlogs in tanker manufacturers.
The new rail tankers “are coming on because you have a huge demand that has grown not only in North Dakota but also in the Eagle Ford,” Keene added.
Shippers also “are doing whatever they can using existing fleets … a refiner that has an existing fleet of rail cars that maybe they were moving refined products. They convert them and move crude oil,” according to Keene.
“We have not looked at rail into Canada although we have talked with the folks working Saskatchewan’s Bakken trend. Everything we have looked at doing is in and around Williams County in North Dakota where we will be building,” Keene noted. “But certainly the opportunity exists wherever there is existing infrastructure, rail infrastructure, there is an opportunity to do manifest or unit trains.
“Currently, we have a huge draw to get it to the Gulf Coast, into the LLS market,” he said, but “non-traditional” markets for inland crude could soon take the rising flows shipped by rail tanker from Bakken and Eagle Ford producers. “Bakken crude is going to California at Bakersfield right now, by manifest trains, a few cars at a time.”
Keene further mused about the potential for Eagle Ford to flood the Gulf Coast, saying that this could back crude up at Cushing and further back in the Bakken.
“Now you have this rush of light, sweet crude coming on the market; where is it going to go? It’s an interesting story,” Keene said. “It will be interesting to see which refiners run it given that a lot of these refiners just a couple years ago were converting to run heavy, sour crude with investments of billions of dollars.”
Musket Trading Makes The Connection
On March 1, Hart Energy also contacted Oklahoma-based Musket Trading and spoke to Dan House, managing director of crude oil. House said the shifting North American oil industry landscape has “been pretty active as far as the changes that are going on. That creates opportunity, so it’s a good place for us.”
Musket owns and operates rail-served terminals; maintains some 2,000 railcars; provides shipment logistics in 39 states and Canada; and distributes crude oil and other commodities via more than 20,000 railcars annually. That includes crude from the Bakken region to the U.S. Gulf Coast.
House confirmed that rail shipments of Canadian crude are increasingly being talked about and occurring in small batches. “We have done a small amount of it, and I know there are a lot of people looking at it in a bigger way recently,” House said.
Regarding Eagle Ford production, House said producers there yield “a lot more condensate type material that will be railed out of the Eagle Ford. The crude seems to have a good local market, but the condensate volumes that they are talking about do not seem to have a natural home down there.”
Hart also asked House if the Eagle Ford condensate could be sent northward to Alberta’s bitumen producers for use as diluent instead of importing it at Kitimat and shipping it by CN rails to Alberta. House agreed that this opportunity is “most likely” and “that’s where we are seeing it make sense.”
Kirby Inland – Heavy Oil to Crude Tanker?
To obtain the waterborne tank barge perspective, Hart Energy spoke with Steve Holcomb, communications officer for Kirby Corp. in Houston – among the largest inland waterway shippers in the U.S.
According to Holcomb: “We carry very little crude oil. We’ve had a lot of inquiries into it, but they have got to get the product to the Mississippi River or the Arkansas River. So it’s a logistics problem of getting the crude to a river system that is navigable.”
When asked about CN’s rail plan, Holcomb said: “A tank barge would be much more economical way to move it than rail cars. But then, of course, you have to have access to [load the crude] on a viable waterway.”
“Our utilization is pretty high, so we don’t have a lot of barges available, but the industry may have some available … If you move refined products in a barge and you switch it over to crude service, then you have a significant cost of cleaning that barge. You cannot carry a petroleum product upriver and bring crude oil back.
“That doesn’t work. It must be dedicated,” Holcomb said, or the shipper could incur something like “$50,000 to $60,000 to clean it.” That cleaning cost could be justifiable, Holcomb said, if spread-over barrels shipped over a lengthy lease commitment.
“If it’s moved in a black oil barge, it’s a little different. We have 112 black oil barges out of our total fleet of 825,” Holcomb told Hart, noting that such costly cleaning procedures would be unnecessary.
Hart noted the EnSys stance that “rail linked in to barge (or tanker) could also play a role in the transport market. Small volumes of WCSB crudes are currently arriving in the Gulf Coast in part via barge.”
Holcomb offered assurance that “Somebody will figure it out before long. If it involves inland tank barges, Kirby will benefit, because it will tighten up the inland barge market. Barge availability will be much less than what it is today, and rates will begin to escalate.”
According to Holcomb, several other black oil barge firms provide similar services. If Hart Energy makes headway on researching those, they will be covered in a future segment of Hart Energy’s Oil’s Changing Landscape special series.