23 April 2013 – Sasol Synfuels, South African manufacturer of synthetic fuels, lubricants and chemicals is specifying high-performance idler frames and skirt seals on its coal conveyors, helping the company prevent spillage and small particles from escaping the material flow. The new components from Martin Engineering South Africa are proving effective at containing fugitive material, minimising safety hazards and lost production time, while significantly reducing maintenance and wash water usage.
Sasol Synfuels was formed in 1950 to commercialise coal-to-liquids (CTL) technology in South Africa, and has evolved into an international integrated energy and chemical company that employs more than 34,000 people working in 38 different countries. The firm develops and commercialises new processes and technologies, building and operating facilities to produce a number of product streams, including liquid fuels, chemicals and electricity.
The firm’s West Coal Processing plant in Secunda produces wet coal slurry that is pressed into fuel cakes, which drop down a five-meter chute. With belt speeds of around 3.6 meters per second, the operation processes approximately 1.6 million tonnes a month. The large volume of material and relatively high speed had a tendency to release small amounts of spillage, which collected over time into significant accumulations, requiring maintenance workers to remove the potential safety hazards and wash the material down into a specially-designed containment system.
Once the source of the spillage problem was dealt with by stabilising the belt, the technicians also installed 42 metres of polyurethane skirting; this was used due to its durability and flexibility.
“The effect of that fugitive material was a drain on manpower that had to be pulled away from core business activities to remove the accumulations every day,” Koos Meyer, divisional manager of the Eastern and Western plants, says. “It required a large amount of water, and it also left us with a significant amount of waste material that had to be dealt with. We were looking for a way to prevent the spillage from escaping the process stream in the first place, so we could avoid the lost material and focus our personnel on revenue-generating activity.”
Representatives from Martin Engineering inspected the five belts, which range in length from 12 to 20 metres, and they reviewed the problem areas with Meyer’s crew. “We found that there was a loss of stability in the belt path as it passed over certain idlers,” observes technical sales rep Ronald Wilmot. “The unwanted motion was disturbing the material enough to liberate small amounts at a time from the flow. Since there was no skirt seal on these belts, the resulting spillage was uncontained.”
During the first phase of the conveyor update, Martin technicians installed a total of 138 Trac-MountTM Idler frames on three 900 mm wide belts structures. “Although the belt was 900 mm originally, we engineered a 1,050 mm Trac-Mount to accommodate a 1,050 mm belt due to increased production,” Wilmot says.
The results since the upgrades were completed have been excellent, with Sasol crews reporting near-zero spillage on the refurbished sections. Washdowns in the area have decreased proportionally. The final two belts are scheduled for similar upgrades, and that effort has already begun. In addition, Martin Engineering technicians have started work on a nearly identical project at Sasol’s East Coal processing plant.