Tank Technologies Keep it Clean

16 August 2009 (Last Updated August 16th, 2009 18:30)

Getting storage cleaning and coating right is a big challenge for the oil and gas industry. It has huge repercussions for the environment and the safety of workers. Dr Gareth Evans looks at the latest innovations shaping the industry.

Tank Technologies Keep it Clean

The oil and gas industry is no stranger to embracing innovation or to addressing the demands of safety. In the past decade, advances in a range of technologies have made the work safer while simultaneously helping to reduce the environmental impact of refineries, offshore sites and allied operations across the world. It is a picture that has been reflected by developments within the tanks and storage space as much as by the sector as a whole, with innovative technology changing the face of corrosion control, coatings, metering and, most visibly, tank cleaning in recent years.

Automated cleaning

The move away from manual systems of tank cleaning, which involve personal and operational safety risk, high disposal costs and lengthy downtime, towards automated approaches always was, in many ways, an obvious one – but the sea change has been gradual in coming. Nevertheless, with the opportunity to speed up the process and minimise waste – both crucial cost concerns – the shift is seen as inevitable.

Among the players active in this sphere are the likes of Oreco, Butterworth, Veolia Environmental and Global Concept. Between them they offer a range of proprietary systems to allow valuable oil to be reclaimed that would otherwise simply have been incinerated or sent for disposal.

"The oil and gas industry is no stranger to embracing innovation."

Oreco’s Blabo process, recently used in the UK at the Esso Fawley refinery, can recover 85-90% of the oil in the sludge and is designed to fit into standard ISO containers. This means that on-site mobilisation or demobilisation can be achieved in a matter of days. Equally important is that the cleaning period is reduced to about a fifth of traditional downtime; Fawley’s cat slurry tank was fully cleaned and ready to return to service in only 15 days.

In terms of immediate costs, direct tank cleaning has the undoubted edge, but the biggest difference is in maximising hydrocarbon reclamation. STS Tank Cleaning Services was responsible for bringing Blabo technology to Fawley and managing director Jorge Oteiza says that being able to reclaim hydrocarbons is financially crucial to the cleaning operation. "This recovered oil is part of what makes this vein of automated tank cleaning a financially viable or even advantageous option," Oteiza says.

The future uptake of automated tank cleaning may largely depend on the attitude of service providers such as STS and the essential driver to optimisation and innovation that they represent by bridging the gap between technology providers and client expectation. With health and safety, environmental and economic factors overlapping so closely around this matter, the push for technological advancement seems unlikely to diminish any time soon.

However, as C&S International Services managing partner Marc Schindler told Hydrocarbon Engineering, human impact has a big impact nonetheless: "80% of accidents in the industry are due to human error and as long as 80% of all tanks are cleaned manually, there is still a lot of information work to be done." A concerted hearts-and-minds campaign may be called for, to spread the word.

Corrosion and coatings

Corrosion is an industry-wide issue, from offshore platforms to service stations, and one that comes with a potentially big cost – environmental as much as economic. In the US alone, more than 2 billion gallons of fuel languish in the underground tanks of the nation’s 180,000 roadside retail outlets and corrosion-related leaks have proved problematic.

"Fawley’s cat slurry tank was fully cleaned and ready to return to service in only 15 days."

Solutions to these difficulties have been relatively easily achieved, principally through the adoption of all-fibreglass tanks, fibreglass coatings and cathodic protection technology, which have been successfully used for ground tanks and pipelines. For offshore applications, however, greater innovation has been required to overcome particular additional challenges that the environment imposes, with two such examples – advances from 3M and Dow Hyperlast – being showcased at May’s Offshore Technology Conference (OTC).

3M’s Corrosion Protection Products marketing manager Henry Hernandez says that its new Fusion Bonded Epoxy (FBE) technology is primarily aimed at pipeline protection."[It is] designed to withstand the heat and provide an innovative solution that offers reliable high-operating temperature coating systems for the oil and gas industry," Hernandez says.

Marketed as Scotchkote, a single 626-120 coating will withstand temperatures of up to 115°C (239°F), or 130°C (266°F) as part of a three-layer system. Scotchkote coating 626-140 goes even further, protecting in temperatures as high as 135°C (275°F) as a standalone and up to 150°C (302°F) when used in a three-layer polyolefin system. With the operational temperatures dictated by the demands of deep down-hole oil and gas production increasingly ramping up, high-temperature corrosion protection for transfer and storage conduits is becoming an important subject.

The challenge of deepwater has also been addressed by a new approach to coating provision from Dow Hyperlast. Arising out of flow assurance insulation coating materials it supplied to Wasco Coatings for the Gumusut-Kakap project in the South China Sea, the company has developed new technology that blends glass syntactic polyurethane (GSPU) coating with insulation systems for remote deepwater sites.

"Corrosion is an industry-wide issue, from offshore platforms to service stations."

Dow Hyperlast's new ETNAFLOW mixing plant offers a reliable, portable blending system, coupled with advanced process control to guarantee accurate formulation, ensure quality parameters are met and provide batch-to-batch consistency in one of the industry’s most difficult environments.

Dow Hyperlast’s Pipe and Tank Division’s global business leader Alex Lane says that the novel GSPU mixing system was designed to help expedite the project, improve materials handling and ensure quality. Given the interest that this system appears to have generated at the OTC exhibition, it looks likely to be used more widely in years to come.

Beyond today’s technology

Tank provision is a fundamental aspect of the industry and, given the essential role that storage and transportation play, the development drive in these technologies is unsurprising. As well as continuing to prioritise these aspects, many predict that future trends in innovation will also see work on metering, monitoring and filtration being further rolled out, along with moves to lower explosion risk and provide the next generation of intrinsically safe technology.

"Full-flow pressure relief valves, redundant overpressure shutdown systems and high-level alarms have become increasingly commonplace."

Many of the necessary building blocks are already in place. At OTC, Expro launched its new ActiveSONAR metering technology – a clamp-on system that can be retro-fitted to a wide range of applications principally in upstream oil and gas operations.

In particular, it is useful where intrusive devices are impractical.

National Oilwell Varco has already applied state-of-the-art filtering technology to avoid condensation, overpressure problems and explosion risk to leak indication tanks. In addition, features such as full-flow pressure relief valves, redundant overpressure shutdown systems and high-level alarms have become increasingly commonplace.

With economic, environmental and safety considerations remaining paramount concerns for the industry, it is inconceivable that the influence they exert on technological development in tanks and storage is likely to wane any time soon.