Demands accelerate – so do solutionsSlop oil recovery at Newalta’s Elk Point facility Case story

Newalta Corporation is a company that sets the standardin industrial waste management in Canada. This involvesdealing with the processing of industrial and oilfieldwaste, and Newalta runs the largest slop oil processingoperation in western Canada, with a 55% share of thisspecialist market.

Complexity increasesAs the intensity of refining operations increased over time, theemulsions that customers sent to Newalta for treatmentbecame more complex and difficult. To deal with this, Newaltaand Alfa Laval worked together to determine the bestmachine/process mix for efficient separ a tion in this difficultapplication. Comprehensive pilot testing and operationsconfirmed that decanters were able to handle very high solidsloads, which is important in slop oil treatment.

As a result, Newalta and Alfa Laval agreed on the installationof two and three-phase decanters at Newalta’s sites atBrooks, Stauffer, Grande Prairie and Fort St. John. Alfa Laval decanter / disc stack combinations were tested at the Hughenden site.

However, improved production methods in the oilfield industrymeant that Newalta found that an increasing percentage ofthe emulsions in the slop oil it was treating could no longerbe broken down with two or three-phase decanters.

A new stage of developmentIn 2000, Newalta took an ambitious decision to expand itsoperations dramatically. These plans included treating andselling more oil, as well as maximizing its value by ensuringmore consistent quality. Based on past experience, Newaltahad found decanters to be the preferred technology. In orderto break down the toughest slop oil emulsions and meet theindustry standard of 0.5% BS&W, the decanters now had tobe combined with disc stacks. What Newalta needed was amachine that could handle high solid loads, extremelychallenging emulsions and high throughputs at the sametime, and it was therefore only natural for Newalta to againturn to Alfa Laval for advice.

After stringent comparative testing, the answer turned out tobe the FOX 15 module, which Alfa Laval had recently de -ve loped specifically to meet the needs of the slop oil market.

The FOX 15 is a high-speed disc stack nozzle centrifuge thatcombines a high capacity for handling solids with the superbseparation performance of the disc stack.

An abrasive situationTrials with the new Alfa Laval FOX 15 module took place atNewalta’s Elk Point facility, aimed at proving that the FOX 15could reach the target level of 0.5% BS&W at a reasonableflow rate.

The slop oil at Elk Point contains large quantities of abrasivesand, partly in the form of very fine particles that cannot beremoved using a decanter. It was therefore crucial that thecentrifuge could withstand the effects of these highly abrasive solids.

The tests showed that the FOX 15 unit provided both asubstantial increase in flow rate (8–12 m3/hr / 35–53 GPM)and exceptio nally good separation, which met the industrystandard in full. However, the tests also showed that the fineabrasive particles caused severe erosion inside the bowl ofthe test centrifuge, especially in the feed distribution zone.

Working together, Newalta and Alfa Laval technicianstherefore made a number of important alterations to thedesign, which resulted in a significant improvement in theability of the FOX 15 to withstand erosion.

Significant supplementThe FOX 15 unit now installed at the Newalta plant at ElkPoint supplements the existing decanter installation, so thatthe process consists of four major components:• A shaker removes larger solids from the slop oil.• Alfa Laval NX series decanters remove the bulk of the

solids.• The FOX 15 disc stack nozzle centrifuge then treats the oil

still further in order to achieve better sales specificationsand to increase the value of the final product.

• The separated water and sediments enter a cone tank,where the solids settle and the water is re-circulated. TheFOX 15 centrifuge only uses water generated by theprocess itself.

Elk Point processed 63,000 bbl in 2002.

Further plansNewalta is continuing to refine its FOX 15 centrifugeinstallation at Elk Point, and has already purchased a similarunit at the company’s mobile processing on-site division.

The oil recovery process at Elk Point

How to contact Alfa LavalUp-to-date Alfa Laval contact details for all countries are always available on our website at www.alfalaval.com

PLS00053EN 0705 Alfa Laval reserves the right to change specifications without prior notification.