IM 2019 June 19 | Page 78

PUMPS AND PIPELINES Leak detection Atmos International has been producing leak detection systems for pipelines for over 24 years, supporting several sectors. While it serves the oil, gas, chemical, aviation and mining sectors, Dr Jun Zhang, Atmos’ CEO, says providing leak detection to the latter can be complex. “The geography, with extreme elevation changes, provides challenges due to regular slack events with severe drops in pressure,” she told IM. “The complex hydraulic changes and nature of mining pipelines require leak detection systems to be carefully implemented. This includes interpreting data from pump signals and the pressure profiles to identify and avoid false alarms.” Gaining better leak location accuracy requires additional pressure sensors, according to Dr Zhang. “For example, having only two pressure sensors along a 150 km pipeline with multiple elevations means less accuracy,” she said. “Adoption of additional hardware provides the operators with a comprehensive solution. “From Atmos’ experience, many slurry pipelines have been designed from the ‘same template’ using the same equipment, station set-ups and distances and similar operations philosophy.” Atmos’ leak detection solutions are able to manage abnormal pressure drops caused by valve stations across pipelines, according to Dr Zhang. “Where there are friction elements that can reduce pressure, by using the pattern of pressure response and the signal from the friction element, false alarms can be avoided.” One of the algorithms used by Atmos Pipe and Wave calculates the friction factor of the pipeline. “This value can be a useful indicator for the client, as more friction means more operating cost,” Dr Zhang said. “The algorithms from Atmos Wave can help reveal different events that may be introducing unwanted frequencies on the pipeline operations. These frequencies could lead to even greater issues if no action is taken.” The Atmos Pipe product calculates a corrected flow imbalance and runs a statistical analysis on it. If flow and pressure change, then Atmos Pipe can alarm and notify the operator to the leak. “Leaks are hydraulic events coming from inside the boundaries of the pipeline instead of outside, as is the case of transients (operational changes such as pump operations),” Dr Zhang said. “With Atmos Wave (the negative pressure wave system), the correlation seen in pressure changes (facilitated by the high frequency data collection units – AWAS) enables the operator to differentiate between normal operating conditions and a leak,” she said. “It can locate leaks within tens of meters.” Atmos Wave Flow, meanwhile, uses a dynamic model based on flow and pressure and uses pattern recognition to identify the unique changes in flow and pressure caused by a leak. “This pattern recognition allows for faster leak detection in minutes rather than hours,” Dr Zhang said. proving the MDX is the most reliable pump on the market,” GIW said. Hernan Palavecino, South America Region Manager for GIW, said: “GIW recognises the importance of the Quellaveco mine to the region. “The award is a result of GIW’s drive for continuous improvements in slurry technologies. We are committed to offering high-quality service while building a long-term partnership with Quellaveco.” Over the border in Chile, Germany’s Pleuger Industries has recently installed six robust high- performance submersible pumps at the Collahuasi copper mine. Pleuger’s 10 in pumps enter the Collahuasi flowsheet during the flotation process where they help dewater the copper sludge. The pumps come with a circa-300 m 3 /h flow rate and are powered by Pleuger ® 2-Pole submersible-motors. Process pumps like the ones used at Collahuasi are placed under extreme operating 74 International Mining | JUNE 2019 conditions, according to Pleuger: “Copper… quickly oxidises the materials from which pumps are usually made. In order to counteract this process, the engineers at Pleuger Industries rely on a corrosion protection concept specially adapted to the customer when designing the pumps.” This is a mechanical maintenance-free protection concept based on forced increased resistance in the circuit, Pleuger told IM. The industrial mineral producer previously employed two independent centrifugal pumps for filling the filter press and dewatering the sludge. This, given the size of the filter plates, appeared to initially be the best option. The company decided to opt for a centrifugal pump with a high initial flow rate of 220 m 3 /h, which pumped sludge at a pressure of up to 3 bar, ABEL explained. “Once the filling phase of the filter press was accomplished, a piston- diaphragm pump was used to fulfil the most demanding process of pressurising at an initial theoretic feed rate of 25 m 3 /h.” However, this system showed high operating costs due to frequent spare parts replacement and high energy draw. “As a solution, ABEL proposed installing only one single piston-diaphragm pump of the HM series, which was best-suited for the high filtering pressure required for the process,” the company said. During the first phase of the filtration cycle, the pump delivers an initial flow rate of up to 50 m 3 /h, but, as the filter chambers fill, solids collect against the filter cloth and counter pressure begins to build. “As this happens, the pump will adapt and automatically reduce its flow rate to compensate,” ABEL said. Flow regulation is carried out by a reference signal from the pressure transmitter to the VFD, according to Abel. During the final filtration phase, the pump operates at high pressure while delivering a low flow rate to the filter press to maintain filtration under high pressure. “The lower speed is more efficient, and provides energy-saving, while pumps using less effective technologies risk incurring high wear and possible damage,” ABEL pointed out. The ABEL HM pump provided a solution with these improvements, according to the company: n Reduction of maintenance costs; n Reduction of power consumption; n Reduction of the cycle time by 25%, and; n Drier filter cake. IM Automatic adaptations ABEL Pumps recently fulfilled a brief from a potassium feldspar and silica sand producer looking to improve performance in its filtration process and continue its effort to lower its environmental impact. For RAG’s German coal mine closure project, ANDRITZ will manufacture and deliver a total of three double-suction submersible motor pumps based on the patented HDM technology