Performance Evaluation for Rotary Vacuum Filters

Tristar, Ltd. is a manufacturer of fabricated components and equipment, including remanufactured filtration systems. The Encoded Digital Guidance (EDG) system is designed to improve filtration performance and reduce energy costs. The EDG-trac Knife Advance system is an ancillary system for a rotary vacuum drum filter (RVDF), which consists of an advancing knife, single motor gear drive, and associated controls. In the EDG-trac Knife Advance system, accumulated solids are cut away from the filter drum surface much more efficiently, while maintaining acceptable solids separation and improving liquid throughput.
OPPORTUNITY AREAS
Remanufacturing is an important means of extending the life of a product and reducing environmental impacts. It was anticipated that, when compared to conventional systems, a remanufactured filter system, which incorporated the newly designed EDG-trac Knife Advance System, would use less energy and water, produce a drier sludge cake, and have a higher filtrate throughput. NYSP2I assisted Tristar with quantifying these improvements.
The goal of this project was to evaluate Tristar’s EDG-trac Knife Advance System at a manufacturing facility and quantify energy reduction, suspended solid removal efficiency, and increased throughput for this system as compared to a traditional RVDF system.
WORK PERFORMED
NYSP2I performed a comparative analysis of the two systems at a chemical manufacturer who was replacing two traditional RVDF systems with two remanufactured systems built by Tristar. The performance of the traditional operating RVDF system and Tristar’s remanufactured “EDG-trac” system was measured using the following key parameters: energy use, filtration rate, sludge moisture content, and effluent quality (suspended solids).

RESULTS FROM THE FIELD
TriStar states that it will rebuild or remanufacture existing RVDF units at its facility or retrofit the EDG-trac system to an RVDF at a customer’s plant. The Tristar Edge-trac Knife Advance System, as installed in a remanufactured rotary vacuum drum filter, exhibited the improved performance results as compared to a traditional RVDF system.
An independent field test at a leading chemical manufacturer in Buffalo, New York, showed that the EDG-trac system increased filtration throughput by 700 percent on average and reduced energy consumption by 87 percent on a per-gallon filtered basis. The study was recently conducted by the New York State Pollution Prevention Institute (NYSP2I) at the Rochester Institute of Technology (RIT). In the study (consisting of two batch tests) the performance of an existing RVDF was measured. The entire filter was then replaced with a remanufactured RVDF and EDG-trac system from TriStar, and the new filter was evaluated under the same process conditions.
IMPROVED FILTRATION PERFORMANCE, LOWER ENERGY COSTS
Ideal solids penetration into a pre-coat filter is 2 to 5 thousandths of an inch. The EDG-trac system removes as little as 1.4 thousandths of an inch per revolution at a drum speed as low as 0.2 RPM. This extends pre-coat life by not cutting away clean pre-coat while maintaining acceptable solids separation and improving liquid throughput, according to TriStar.
EDG-trac also features a highly efficient, single-motor VFD to reduce energy use and cost. A fully automated PLC controls the advance speed, retract speed, and drum speed, allowing precise control and providing valuable information to operators, the company states. An automatic high-speed retract mode reduces time between cycles and allows the filter to be recycled and put back online quickly.
TriStar says that the company can remanufacture an entire RVDF including EDG-trac at 60 to 70 percent the cost of a new filter in eight to ten weeks. It can also retrofit the EDG-trac system to any installed RVDF. TriStar also fabricates a wide range of process equipment including pump skids, heat exchanger skids, pre-coat systems, frames, platforms, piping systems, and other custom projects. The company also provides welding services including piping, valve ends, equipment repair, sanitary piping, and stainless steel tubing. ■
About the Author
Charles M. Harrigan III is the sales and marketing director at TriStar Ltd. He can be reached at 716.873.0081 or via email at charrigan@tristarltd.com. Established in 1985, TriStar Ltd. is a remanufacturer of filtration equipment including Rotary Vacuum Drum Filters, Belt Filters, Vacuum Belt Filters, and Filter Presses. In addition, TriStar manufactures a proprietary line of Hot Water Sets. For more information, visit www.tristarltd.com.