With oil production disrupted this past summer in the Gulf of Mexico because of two hurricanes, it can't be anything but good news that oil is expected to be brought up in the southern part of the North Sea next summer.

Recently, KSB Aktiengesellschaft of Frankenthal, Germany, supplied 23 pumps to Petro-Canada for a drilling platform in the De Ruyter oil field. The Canadian oil producer is having the 12,500-ton platform built in the Netherlands, and is planning to moor it to the seabed about 35 meters (110 feet) deep and 60 kilometers (37 miles) northwest of The Hague on the Dutch Continental Shelf.

Submersible borehole pumps for the De Ruyter project during final assembly at KSB's factory in Homburg, Germany.

KSB supplied submersible borehole pumps made from a special duplex steel. This is a corrosion-resistant type of stainless steel capable of withstanding the damaging effects of seawater. The pumps are driven by high-voltage motors that are filled with fresh water. Those motors have a 6,000-volt power rating. A mechanical seal stops the seawater from entering the motor space. To make sure that any water losses are immediately replenished, the motor space is also connected to a constant-level fresh water storage tank.

The De Ruyter development will initially consist of three production wells. Oil export will be via offshore loading to a shuttle tanker. Petro-Canada is one of Canada's largest oil and gas companies.

Researchers at the Pennsylvania State University have demonstrated a protein purification process that they say offers both high throughput and high selectivity.

The throughput is achieved via ultrafiltration, the high specificity via electrically charged dyes that bind to a target protein.

According to the developers, the process can broaden the scope of ultrafiltration.

"Classically, in ultrafiltration, the size of the pores in the filter determined what could get through," said Andrew Zydney, a professor of chemical engineering, who helped develop the process.

Recent studies, however, showed that additional retention could be achieved with electrically charged membranes if the protein were of the same charge as the membranes, he said.

The process tags the protein with a small, negatively charged dye molecule that can be easily removed. When the solution to be purified flows through a negatively charged ultrafiltration membrane, the protein—now negatively charged because of the attached dye—is retained in higher proportion than when it wasn't tagged, Zydney said.

The team performed experiments using just one protein, but Zydney said it should be possible to enhance the selectivity of other protein separations, which would offer new opportunities for membrane systems.

We've all walked through an air curtain at one time or another. It's that stream of air that blows down on you when you leave a public building. It keeps conditioned interior air from escaping out of doors. The curtain can also control dust and humidity.

Battelle, the technology research organization based in Columbus, Ohio, used an air curtain for containment of a different sort. It seems that a government agency wanted a containment facility that could be used to test methods of detecting chemical and biological agents. Although tests would use simulant particles or aerosols instead of real deadly agents, many of the substitutes are mildly toxic and so must be contained.

The design had to provide optical access for a range of light wavelengths, thus precluding physical windows and requiring open ports to the atmosphere. The agency's request for proposal included an engineering study of methods to contain the simulant particles in the presence of the open ports.

Battelle built a demonstration unit to study air curtain behavior. It had a dissemination chamber 4 meters square and 5 meters high, where simulants were introduced. A 3-meter-diameter port opens to an 11-meter-long chamber that contains three air curtains spaced 4.5 meters apart on center. The air curtain chamber connects through another 3-meter port to a vestibule chamber that is exposed to the ambient air through dampers. The air curtains were provided by Biddle Air Systems Ltd. of Warwickshire, England, which consulted on their design and use.

Physical testing measured aerosol concentrations in and around the facility. Hot wire anemometry, pitot tubes, and smoke visualization techniques were used to characterize the flow field.

Battelle studied the test structure in computer models, executed by Steve Ricci, a senior research engineer who was principal investigator, and Jim Saunders, a research leader. Engineers reasoned that if they could verify the accuracy of computerized fluid dynamics in simulating air curtains, CFD software could be used in the design of an actual containment facility.

Physical tests of the demonstration unit confirmed that it achieved the required containment. The concentration of particles in the ambient air was about five orders of magnitude lower than that of particles in the dissemination chamber.

However, flow field visualization tests showed that when more than one air curtain was operating, the curtain closest to the dissemination room showed some instability. When the middle and inner curtains were operating at the same time, the inner one exhibited periods of oscillation lasting a few seconds.

Although the system was undesirable from the viewpoint of design, it presented an opportunity to demonstrate the ability of CFD modeling. Using software from Fluent Inc. in Lebanon, N.H., engineers ran a simulation of the system that reproduced the oscillatory patterns of the inmost curtain.

Battelle was able to modify the design to provide sufficient containment while taking advantage of the physics of air curtains to stabilize the dynamic behavior. The solution lay in avoiding the interaction of air curtains by using a single, wide air curtain with a lower velocity to minimize disturbances on the jet boundaries and a suitable set of blower flow rates to reinforce the curtain with the net incoming ambient airflow.

CFD is now being used extensively in the design of the actual containment facility.

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