The Project
Pipe at a phosphate mine is currently used to convey a gypsum slurry mixed with sand tailings during upset conditions. The above-ground pipelines have discharge pressures of about 80 psi with slurry temperatures up to 90°F in the summer. The abrasive nature of the gypsum-sand slurry causes material wear in the pipelines. While having experienced varying degrees of success with materials such as lined steel, high-density polyethylene (HDPE), and primarily fiberglass-reinforced pipe (FRP), the mine was on the lookout for an innovative solution to improve the life of their slurry lines.
The Solution
In laboratory testing conducted by Performance Pipe, Driscoplex® 4800 series medium-density polyethylene (MDPE) pipe proved to have better abrasion resistance than two PE4710 HDPE pipe resins tested, experiencing less material wear than the HDPE pipe samples in both ambient and raised temperature conditions. Test results are explained in PP844-TN Slurry Abrasion Resistance in Polyethylene Pipe. Encouraged by the test results, the mine put in 5,100 ft. of 34-inch DR13.5 and DR17 Driscoplex® 4800 series MDPE pipe to see how it compared in abrasion resistance to their existing HDPE lines.
The Results
The Driscoplex® 4800 series MDPE pipe installed in the gypsum slurry lines has experienced less wear over the past year than their existing DR17 and DR13.5 HDPE pipes operating under similar design conditions. These results support the findings of Performance Pipe’s testing detailed in PP844-TN, as well as additional research that has shown that the abrasion resistance of polymers is principally dependent on the effective number of physical cross-links per macromolecular chain of the polymer structure. The Driscoplex® 4800 series MDPE pipe resin has more effective physical cross-links (i.e. has a smaller percentage of shorter chains that do not contribute to the polymer’s structural connectivity) than the HDPE pipe resins. This results in improved abrasion resistance for the Driscoplex® 4800 series MDPE pipe. The positive field results encouraged the mine to order another 5,000 ft. of 32” DR17 Driscoplex® 4800 series MDPE pipe to continue integrating the improved abrasion-resistant pipe throughout their plant.
Before using this product, the user is advised and cautioned to make its own determination and assessment of the safety and suitability of the product for the specific use in question and is further advised against relying on the information contained herein as it may relate to any specific use or application. It is the ultimate responsibility of the user to ensure that the product is suitable, and the information is applicable to the user’s specific application. Performance Pipe a divisional of the Chevron Phillips Chemical Company LP does not make, and expressly disclaims, all warranties, including warranties of merchantability or fitness for a particular purpose, regardless of whether oral or written, express or implied, or allegedly arising from any usage of any trade or from any course of dealing in connection with the use of the information contained herein or the product itself. The user expressly assumes all risk and liability, whether based in contract, tort or otherwise, in connection with the use of the information contained herein or the product itself.