Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1275515
24 | July - August 2020 | www . machinerylubrication.com OIL RECLAMATION standing of decontamination processes and technologies available. Some of the more common contam- inants frequently found in lube oil systems are water/moisture, solid parti- cles, process gases, high temperatures and varnish deposits. Ingress of these contaminants has detrimental effects on lubricants and equipment components. Most times these effects are long term with progressive deterioration that can potentially lead to failure. However, some consequences are immediate and can be catastrophic. Using best practices, systems can be designed or modified to exclude contaminant ingress. Among the areas of contaminant ingress to review include gaskets, worn or damaged seals, open hatches and pipes, dirty hoses, dirty top-up containers and dirty new oil. Focus is required on the types of contamination that is in a lube oil system. Firstly, examine oil analysis reports and review any abnormalities. Look for data changes and trends (both increasing and decreasing). If a report provides cautionary or critical warnings, it must be investigated further. Resa - mple and retest the lube oil. A retest will confirm accuracy of the results and can prevent unnecessary actions. In the absence of oil analysis reports, take alternative options such as using your senses. is is by no means best practice. Use your sense of touch to feel for tacky, thin or solid material. Use your sense of smell to detect fuel, process gases, burnt, foul or pungent odors. Use your vision to look for water, foam, air bubbles or a cloudy or dark appearance. For solid contaminants, another alternative is to conduct a field patch test. is provides a great snapshot of solid contaminants in the lube oil sample. However, particle counting is the best practice available. Particle counting provides counts of actual particles identif ied in the range numbers of the ISO code. is is very helpful in selecting filters required to remove solid particles. Once contaminants are determined, it is imperative to remove these as soon as possible. Following are some of the most popular methods for removing these contaminants. Water Water and heavy solid particles will naturally settle at the bottom of reser- voirs. If oil analysis results identify high levels of moisture beyond specified limits, it must be reduced. For applications with large ingress of water, a centrifuge will be very effective. However, it will not remove moisture below the saturation point. For lube oils, it is best to remove moisture to as low as reasonably possible. erefore, in most situations, a vacuum dehydrator is used to remove large volumes of water and to meet moisture limits of the oil. In the situation where there is a coolant leak or steam leak, moisture ingress maybe continuous. A balance will have to be achieved with a vacuum dehydrator to ensure that moisture limits are main- tained. Dry air and nitrogen are best suited for maintaining lube oils with existing low moisture levels. For vacuum dehydrators, the tech- nology has evolved significantly. Most systems utilize low wattage density heaters. This prevents lube oils from becoming burnt as it passes over these heaters. Vacuum pumps have improved significantly resulting in more reliable operations. Foam sensors have also been included with controls to avoid foaming. is reduces the risk of vacuum pump failure and oil spills. Vacuum chambers' designs have been improved resulting in improved mass transfer efficiency. Vacuum dehydrators are becoming more reliable in the industry. Gases Most times these gases are directly related to process gases. ey are typically dissolved and can be easily removed using vacuum dehydration. Note that some gases are dangerous. In this case, the vacuum pump exhaust must be vented to a flare. Solid Particles ese particles are removed via filter media. e choice of media can be chal- lenging, as they vary in performance. However, a logical process should be adopted where filters are selected on the type and number of particulates to be removed. ere isn't a simple process to the selection. However, obtain a current particle count with particle distribu- tion. is will give you an indication of particle size and quantity. If filtration is off line with easy access to change filters, then lower cost filters can be explored. Start with the micron size in abundance and remove these particles. Then replace with a lower micron size. Change filter based on recommended differential pres - sure or filter indicator. Repeat process until particle count is acceptable. is will avoid using depleted multiple smaller micron filters which typically are more costly. For pipeline flushing, screen mesh or surface media can be used initially to remove the bulk contaminants followed by standard filtration. Efficiency or beta ratio is sometimes not well understood. Some manufac - turers state their filters are high efficiency or absolute rated. Unfortunately, there is no standard that identifies an absolute