Tank Storage Magazine v10 i01


Volume: 10
Issue: 1
Date Published: January 13, 2014



Outlook 2014

Hear terminal operators’ thoughts on what the market holds for the year ahead. 

The build-out opportunity

Deals, new partnerships and terminal construction stole the storage sector spotlight in 2013. For 2014, forget about Keystone and refining centres; it’s the terminals serving them that are moving forward with their own plans for Bakken and Athabasca crude   Independent terminal operators supplying crude oil to refineries want their hands on shale play crude, so they are willing to deal or build at breakneck speeds and big expense to get it. ‘Just witness what has happened in the last five years. We want to make sure we are investing when we have the opportunity, particularly in midstream,’ says Marathon Petroleum’s CFO Donald Templin. ‘The buildout opportunity is now, and we don’t want to miss out.’ Marathon certainly has an aggressive midstream growth strategy, which spawned a wholly owned subsidiary named MLPX to focus entirely on logistics and distribution. ‘Fully committed to building out its transportation assets, Marathon is now signed-on to two of the biggest pipeline-to-terminal construction projects in all of the tank storage sector,’ says Angela Graves, media representative for Marathon.

US EPA confirms ASTM D6377 as an alternative test method for measuring vapour pressure of crude oils

A new method for measuring the true vapour pressure (TVP) of crude oils is spreading quickly within the oil and gas industry. At request of API, the US Environmental Protection Agency (EPA) has confirmed the use of the ASTM D6377-10 standard as an alternative test method for the determination of the TVP of high VP crude oils. Widely used by the industry, the new method is now included within the Ametek Grabner Instruments vapour pressure testers provided by Petrolab. As defined by the International Maritime Organisation, the TVP or bubble point vapour pressure is the equilibrium vapour pressure of a mixture when the vapour/liquid ratio (V/L) is zero. A V/L of 0 can be achieved if a container is filled to the top with crude oil. This condition is typical for floating roof tanks, where the roof is floating directly on the crude oil. As clear as this definition seems, a correct interpretation of the TVP term always depends on the specification for which it is used. In refining, the term TVP often is used to reflect the specific conditions of storage or transport. For example, if a truck or a ship is filled 95% with crude oil and only 5% vapour space remains, the vapour pressure at a V/L = 0.053 may be referred to as TVP. Within US EPA title 40 regulations, the term TVP is used for a TVP estimate calculated from a D323 Reid Vapour Pressure measurement and the crude oil´s tank stock temperature.

Finding the right balance

How NuStar optimised its railcar loading operations at its US terminal in California   NuStar has terminal operations across the country and its Stockton facility in California is one of its largest. It features 33 storage tanks, with a total storage capacity of nearly 900,000 barrels, for a mix of petrol, diesel/ULSD, ethanol and aviation fuel. It sports a three truck loading rack with nine loading lanes, as well as two rail spurs with 16 loading/unloading positions. The facility also offers automated additive and dyeinjection services, truck scales and dry warehouse storage. ‘We had a customer ask us if we could move red-dye diesel fuel by rail to a mining site in Nevada,’ explains Dan Thomas, terminal manager at NuStar’s Stockton facility. ‘We could and we began by transloading the red-dye diesel via a fleet of trucks that would fill up at our truck rack and then drive to the rail siding, where they would be pumped off with a portable pump into the railcar. We would need to use three trucks running a continuous loop from the truck rack to load one railcar.’ Finding theright balanceThis was not only a repetitious process, but also a time-consuming one. As only one truck could be unloaded at a time, it would take more than 10 hours to load five railcars. Since the railcars were being bottom-loaded from the trucks, there were also ergonomic and safety concerns for the technicians who were facilitating the loading process.

On spot loading: hitting the mark?

Loading facilities are categorised depending on the required daily or annual liquid transfer rates. Filling systems include top, bottom, series and on spot loading. Top and bottom loading takes place when the loading capacity is low. Series loading facilities are extended, linear facilities with a large number of top loading arms arranged in series. On spot rail car loading facilities are filling stations for rail cars with a top loading system and a high filling capacity – up to 1,000m3 per hour. Several products can be loaded at one station.

A breakthrough design in aluminium internal floating covers

Since the 1970s, the design principles used in the fabrication, installation and upkeep of internal floating covers (IFC) have essentially remained the same, while the issues of reliability, lifeexpectancy, time and costs associated with maintenance, testing, cleaning and repairing, as well as the hazards posed by life-threatening vapour leakage, have persisted. The skin and pontoon tank cover model developed in the ’70s is still widely used today, despite the fact this type of roof frequently fails due to inadequate flotation, poor design, improperly assembled components, structural members spaced across a large grid, poor test port design and the use of plated fasteners. In the mid-1990s, tank cover designs for the petrochemical industry took a step forward with the invention of enclosed welded honeycomb ‘sandwich’ panel roofs. However, neither the pontoon nor the honeycomb compartment covers really solved the problem of leaks and emissions. Moreover, both pontoon and sandwich panel roofs have enclosed compartments that often trap gasses and liquids and become ‘hot’.

Behind the functional safety: SIL1?, SIL2?, SIL3?

Based on the standard IEC 61511, how should you determine the SIL value of an overfilling protection system to enable you to reach your safety target without over-engineering?   Process safety became a hot issue after the Piper Alpha disaster in 1988, which started the evaluation of the state of oil industry from a safety point of view, and resulted in a standardisation process publishing IEC 61508, IEC 61511, ISA-TR84.00.02-2002 and ANSI/ISA-84.00.01-2004 (IEC 61511-Mod) standards. Nowadays, it is a general requirement for companies to operate functional safety management (FSM) systems with goals to identify the management activities that are necessary to ensure the functional safety objectives are met: • Maintain the operability of safety instrumented system (SIS) all over the lifecycle • Maintain the level of safety (SIL value) of safety instrumented functions (SIF) all over the lifecycle • To place and/or maintain the process in a safe state.

Evaporative loss from floating roof tanks

All stored liquid has a vapour pressure, which depends on the surface temperature and the composition of the liquid, causing evaporation. Under static conditions, it establishes a balance in the vapour concentration, after which no further evaporation occurs. However, tanks are exposed to dynamic conditions that break this balance, causing a continuous evaporation. These variable dynamic conditions of temperature, pressure and wind speed are causing continuous evaporation. According to API there are two types of losses on a floating roof tank: standing loss and working loss.

Benefits of robotic in-line inspection tools

With a large number of tank lines originally built without pig launchers and receivers, it falls upon current integrity engineers and risk managers to determine how best to address facility piping which may not have been inspected previously. With tanks out of service, API 653 inspections provide a convenient opportunity to inspect and/or replace below ground tank lines. A thorough inspection of each tank line ensures environmental and human safety and eliminates blind replacement of piping. With more emphasis being placed on pipe inspection rather than blind replacement, the industry has been faced with the challenge of finding inspection solutions which employ proven technologies that provide reliable, cost effective inspection results.

Overspill level protection for remote tank storage installations

How the latest wireless enabled guided wave radar level transmitters and vibrating fork switches, help operators maximise tank capacity, while minimising the risk of overfilling and potentially hazardous spillages, even in remote installations   In tank storage applications within the oil and gas, chemical, petrochemical and pharmaceutical industries, having access to accurate tank level data is important for process control and inventory management. Overflow presents a risk to the environment, damage to the plant and is potentially harmful to workers and people living nearby. Several high-profile accidents involving storage tanks have highlighted the need to increase the protection to primary containment systems. More stringent legislation covering overspill protection on critical applications now requires a level of redundancy to be installed. For many customers the combination of guided wave radar (GWR) transmitters, for continuous level monitoring and vibrating fork point level sensors for high and low level alarms, provides an ideal solution for many applications. However, one aspect that has held back the application of increased level instrumentation is a lack of an existing cable infrastructure connecting the remote tanks. The cost of installing new wiring can include ducting, cable trays and the digging of trenches, which can be cost-prohibitive. There is also the inconvenience and issues of performing the work while the site is operating.

Eagle Ford shale tank battery installed with high performance secondary containment liner

With so much growth happening in the US shale industry, it is more important than ever that companies do everything they can to avoid spills and other incidents that could endanger lives, as well as the industry’s reputation. In the summer of 2013, one south Texas 7,000 barrel oil facility tank required new secondary containment. Meador Coating Services, a division of Meador Industries, a US provider for oil and gas plant services, completed the job using 100% pure polyurea from VersaFlex.

Keeping oxygen to a minimum during welding

Whether welding small tanks, associated pipework or large tanks with accessories for stainless steels, nickel alloys, titanium and other metals, it is important to ensure the oxygen level is kept below specific guidelines to keep discolouration, oxidation and coking either to an absolute minimum or totally eliminated. This is carried out by flushing out the air surrounding the weld joint using an inert gas, such as argon or helium, until the oxygen level approaches 50 parts per million (ppm). Some operators will attempt to use nitrogen as a cheaper alternative. However nitrogen is not as inert as sometimes thought and it can react with some stainless steels and alloys to create undesirable changes in metallurgy.

Best year yet for Tank Storage Asia

This year’s speakers drew in record numbers to Tank Storage Asia in Singapore in December. The likes of Jasper Schmeetz, commercial manager at VTTI Asia; Chong Rok Park, president of the Ulsan Port Authority in the Republic of Korea; and Xu Ruiqing, chief commercial director at Sinopec Kantons all ensured the conference was the busiest yet.