Have you ever had high levels of acid in your phosphate ester fluid? Well, check out my new story… A large power plant, located on-site at a paper mill, contacted me regarding some issues they were having with acidic phosphate ester fluid. What is that stuff, you say? Phosphate ester is a synthetic liquid that is used as a hydraulic fluid or as a lubricant (lube oil) because it has a high thermal tolerance. It is often used in high-temperature applications because of its high flash point and self-extinguishing ability. Why were they having issues with its acidity? Well, the lower the pH of oil (i.e. the higher the acidity) the more corrosive it can become, which is bad for the machinery. Higher levels of acid will also have an adverse effect on the additives in the oil, causing them to drop out or degrade in effectiveness.
After thoroughly reviewing their application, I suggested that they use fullers earth filter cartridges in order to lower the acidity of the the phosphate ester fluid. Fullers earth is basically diatomaceous earth media in bulk form, but it’s filtered using a clay treater. With certain brands of phosphate ester fluid you must use Selexsorb, which is an activated alumina bulk media used to condition the oil. However, fullers earth as a filter media is typically less expensive than the Selexsorb media. Fortunately for the paper mill, their brand of phosphate ester was compatible with fullers earth. I also recommended that they use fullers earth because some of my other customers had reported good results using it in similar applications.
Prior to us sending the fullers earth elements the acidity level of their phosphate ester was close to a pH of 2. During 3 months in operation with the fullers earth cartridges that we supplied, their acid numbers have returned to being within the manufacturer’s specifications. To this day the acidity remains at a near-neutral pH of 6. Success once again!
Do you have a question about filters or filtration? Feel free to contact us anytime. Our friendly team of experts will be happy to help you out with your particular issue.
Until next time!
Paul at Precision Filtration Products
P.S. Have you seen our latest videos? If not, click here to check them out now!