Martin Engineering South Africa has recently completed a project to help contain fugitive material at Sasol Synfuels’ West Coal processing plant in Secunda, while significantly reducing maintenance and wash water usage. The processing plant produces a wet coal slurry that is pressed into fuel cakes, which drop down a 5 m chute, with belt speeds of around 3.6 m/sec. The operation processes approximately 1.6 Mt/mth and there are often small amounts of spillage due to this large volume of material being processed at high speeds. This spillage over time can build into significant accumulations, requiring maintenance workers to remove the potential safety hazard and wash the material down into a specially-designed containment system.

 “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,” explained Koos Meyer, Divisional Manager of the Eastern and Western plants. “It required a large amount of water, and it also left us with a significant amount of waste material that had to be addressed. 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 12-20 m, 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. 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.” observed Ronald Wilmot, Technical Sales Representative. Martin Engineering technicians installed 138 Trac-Mountidler frames on three 900 mm wide belt structures during the first phase of the conveyor update. “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 said.

The design fits into tight spaces between support cradles and  the modular units deliver proper belt carriage to stabilise the load and improve sealing.  They can be serviced by a single worker, without the need to raise the belt or remove adjacent idlers and have been engineered with a sliding frame on a stationary base. The assemblies can be supplied with steel or impact rolls in CEMA Class A,B,C,D or E. Once the source of the spillage problem was addressed by stabilising the belt, technicians also installed 42 m of polyurethane skirting to provide additional dust sealing.  “We supply large amounts of this skirting to Sasol, primarily because of its durability and flex,” Wilmot added.  “It works very well in these applications.” Sasol crews have been reporting near-zero spillage on the refurbished sections. Washdowns in the area have decreased proportionally. “We’re very happy with the upgrades,” Meyer concluded. “The equipment is performing well, and the installation was neat and professional.” 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.