... Filtration Forethought - North American Energy Pipelines

Filtration Forethought

Reducing Waste Oil on Pipeline Engines by Improving Compressor Maintenance
By Kevin G. Kroger

feat-filtr-engineThe unprecedented surge in interest about the environment and the concurrent growth in the media’s focus on the subject mean that it’s no longer enough to look like a responsible corporate citizen. The oil and gas industry is expected to take swift and definitive steps to ensure it is doing everything possible to be ecologically responsible.

Waste oil is a natural byproduct of the combustion engines that power compressors, which pump oil and gas from one point to another along the pipeline. According to the American Petroleum Institute (API), a single gallon of improperly disposed used oil can contaminate 1 million gallons of drinking water. Waste oil is a natural byproduct of the combustion engines that power compressors transporting oil and gas from one point to another along the pipeline and can be recycled and re-refined for use as heating oil, asphalt or heavy lubricant, resulting in a more expensive fuel material and reducing the amount destined for disposal. But even after being recycled and re-refined the used oil has its own set of problems. Substantial amounts of heavy metals and organic mineral such as carbon, potassium, magnesium, iron, zinc, aluminum, lead, nickel and cobalt, all of which come from engine parts as a result of wear can be found in recycled oil.

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One practical solution that is gaining traction in the oil and gas industry is bypass oil filtration. This technology allows engine lubricating and hydraulic oil to remain viable for an extended period, avoiding oil drains and thereby reducing the quantity of used oil by as much as 90 percent. By keeping the oil continuously clean of contaminants and base additives intact, oil can be used almost indefinitely. Use of a simple oil analysis will confirm if the oil is good for continued use.

Bypass filtration technology extends the life of the oil and elongates the life of the engine, reducing additional pollution contributors of these components as well. As an added benefit, steps taken to reduce these pollution contributors also will significantly reduce operating costs.

The success or failure of a pipeline operation is largely dependent on the performance of the compressor needed to move crude or natural gas from the field to storage or refineries and from refineries to market. As a result, meeting contractual commitments can often come down to the reliability and efficiency of your compressor, and making sure your compressor’s engine is running at optimal performance is a good way to avoid unnecessary maintenance costs.

Proper scheduled maintenance is key to assuring peak performance. However, this equipment typically operates continuously under high load factors, and in order to perform proper maintenance, a full shut down of the equipment may be required for scheduled maintenance. If inadequate maintenance or scheduled maintenance is delayed for any number of reasons, this would lead to increased stress levels on the engine, drastically reducing performance and/or increasing equipment deterioration. In the event of equipment deterioration, higher proportions of unscheduled interruptions for unspecified durations occur, and operating cost begins to mount up.

Performance issues and deterioration can be addressed by keeping the lubricating oil clean. When lubricating oil — which is designed to lubricate, seal and cool — becomes dirty, it allows impurities in the oil to create friction, which leads to higher running temperatures, a contributing factor to high stress levels on an engine. Over time, lube oil becomes less effective because of contaminant saturation and additive depletion.

Cutaway view of the puraDYN System.

Fig. 1: Cutaway view of the puraDYN System.

The life expectancy of compressor engines can be safely and significantly extended if lubricating oil is kept free from solid, liquid, and gaseous contaminant and the base additives are replenished. Certain large bypass oil filtration systems provides the technology to keep large quantities of oil continuously clean and is becoming an indispensable factor in a well-rounded maintenance program for compressor engines, especially if those compressors need to run 24/7 and are situated in remote locations.

Working in much the same way as a kidney dialysis machine, the puraDYN System diverts engine oil at a slow rate of 6 to 8 gallons per hour (gph) or 22 to 40 liters per hour (LPH) (slightly higher for hydraulic applications), cleaning lube oil of its impurities and feeding it back to the engine or hydraulic tank (Figure 1).


A Colorado-based natural gas pipeline operator has been using oil bypass filtration for more than eight years, primarily to increase time to overhaul, greatly reducing the lifecycle
cost of the engine. The fleet is comprised of 61 natural
gas compressors; 35 are powered by Waukesha 7042GL
engines, 26 with Cat 3516 engines, and all use Puradyn’s
largest system, the TF-240.

Puradyn’s TF-240 model.

Fig 2: Puradyn’s TF-240 model.reducing the lifecycle cost of the engine. The fleet is comprised of 61 natural gas compressors; 35 are powered by Waukesha 7042GL engines, 26 with Cat 3516 engines, and all use Puradyn’s largest system, the TF-240.

The puraDYN TF-240model (Figure 2) micro-filters an oil sump capacity of 85 gallons (322 liters) and is designed to be used in multiples where engines can hold up to 450 gallons (1,703 liters) of oil. Described as a workhorse, it can easily handle 24/7 operations in demanding environments.

Onsite, every component of an engine is inspected as it comes apart for an overhaul. At the first overhaul interval after installing the system, the engine was torn down, as customary, and the components inspected. Management noted how clean the parts were and from that point on, they were able to extend overhaul intervals, on average, by 25 percent or 10,000 hours.

Oil drain extension. High efficiency micro-filtration removes solid contaminant to below one micron and all liquid and gaseous contaminant. Base additives in engine oil are replenished through a proprietary additive package, maintaining the engine oil’s chemical balance and viscosity properties. When contaminants are removed and base additives replenished, oil drains can be safely extended because of the oil’s cleanliness and chemical balance has been kept in check, a fact verified by simple oil analysis.

Fig. 3: Replacement filter element change.

Fig. 3: Replacement filter element change.

Oil condition monitoring. Instead of changing the oil at regular intervals, an oil sample is taken for analysis. Oil analysis, which is becoming standard in major company maintenance programs, provides instant and continuous monitoring of the oil’s condition and alerts the end-user to potential problems before they occur. As long as the sample returns as “good for continued use,” the lubricating oil does not have to be changed; the only change is to the replacement filter element (Figure 3).

Equipment readiness. Compressor engine maintenance often requires a full shut down of the equipment. Even scheduled overhauls of a compressor can keep equipment out of service for a few days. But an oil filtration system can be done with the engine running. Taking an oil sample or changing the replacement filter element can be done without any equipment shutdown.

Cost reduction and fast payback. Avoiding the need to halt operations for long periods of time, tear down equipment and/or make repairs due to oil-related maintenance issues can save hundreds of thousands of dollars, and for large operators, millions. In addition, by extending oil drain intervals on compressors that are running on continuously clean oil, new oil purchases and waste oil disposal costs alone can be substantially reduced, in some instances up to 90 percent. On top of costs savings and ease of use, your engines run at optimum performance and run longer.
An efficient bypass oil filtering system should:

  • Filter solid contaminants, including wear metals, soot, dirt, sludge, etc., to below 1 micron. Conventional oil filtration filters solid contaminants to approximately 5 to 10 microns, but anything over 1 to 1.5 microns will create wear in engine components. The best bypass filters are designed to achieve micro-fine filtration to trap particulates ranging in size from 5 microns to below 1 micron.
  • Remove liquid (water) and gaseous contaminant, including sulfur oxides (SOx), nitrogen oxides (NOx), fuel vapors, etc.
  • Replenish base additives in oil.

feat-filtr-chartLubricating oil is becoming more of an operations cost and the life expectancy of field equipment must be extended in order for companies to improve their profit. The direct cost of new oil purchases is only the tip of the operations cost-factor in the indirect costs of transporting and storing oil at remote locations and diverting your crew and equipment for oil-related maintenance issues and it’s easy to see how fast a positive impact bypass oil filtration will have on any company’s bottom line.

Kevin G. Kroger is president and COO of Puradyn Filter Technologies Inc. (www.puradyn.com)

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