Submersible pump a fit for petroleum coke sump service

Problem: PABTEX, an affiliate of Kansas City Southern Industries in Port Arthur, Texas, is a major bulk commodity handling facility specializing in exporting petroleum coke. When the raw petcoke is transported to PABTEX’s terminal in bottom-dump railcars, the coke goes to a system of shakers, which breaks it into smaller chunks that are easier to transport on a conveyer system. However, below the shakers is the open conveyer shaft that goes down 70 to 80 feet below the ground. Due to the risk of rainwater filling up the conveyer shaft, a large sump was sunk into the bottom of the shaft to make sure that water could be pumped out to an existing retention pond. With the shakers directly above the bottom of the conveyer shaft, pieces of petroleum coke fall into the shaft and eventually washed into the sump.

Solution: Todd Wilkes, maintenance supervisor of Savage Gulf Services, had tried several submersible pumps. However, the petcoke was too abrasive and, without an integral agitator, solids settled out and clogged the pumps. Tim Weber, sales manager of Saladin Pump, suggested a KZN110H: a 15 hp high-head, hard-metal-agitator slurry pump from BJM Pumps. All wetted parts are constructed of abrasive-resistant 28 percent chrome iron. A replaceable hardened wear plate is located on the suction side, where erosion harms pump performance. An integral agitator fluidizes settled solids into a slurry, making them easier to pump with less chance of clogging. The semi-open impeller handles abrasive solid concentrations as high as 70 percent by weight.

Result: Saladin Pump installed a KZN110H in the sump for a 60-day trial. The trial was so successful, with no clogs or wearing issues, that Savage Gulf bought the pump, and 60 days later bought a backup unit. 877/256-7867; www.bjmpumps.com.

Related: Greening the Plant: LEEDing the Way

Cleaning system eliminates biomass, increases productivity

Problem: Shane Donoghue, a wastewater facilities manager in a large Australian city, saw accumulation of FOG and biomass up to 4 feet deep in a month in a lift station. This required tens of thousands of dollars in maintenance, including weekly to biweekly vacuum truck services and confined-space entry to clean the well by hand. “Sometimes the FOG would build so thick, it was too great of a load for a single truck, and they would have to come back again,” says Donoghue.

Solution: Donoghue purchased the EP-1300 conditioning and cleaning system from Anue Water Technologies to relieve the department’s operations budget. The unit operates by recycling a small amount of discharged flow to create ongoing surface agitation that prevents FOG buildup and promotes aerobic activity.

Result: The installation immediately reduced maintenance checkups from weekly to monthly, and the lift station no longer required continuous vacuuming. “Our need for confined-space entry was just about eliminated,” says Donoghue. When considering the reduction in labor costs, vacuum truck cleaning and tipping fees, a single unit saved $15,000 in the first year and nearly $22,000 in the second year. The change in cleaning routines reduced maintenance costs by nearly 50 percent. 760/727-2683; www.anuewater.com.

Related: Top Performer - Plant: Clean Plant, Clean Effluent

City chooses electromagnetic variable-speed drive for pump application

Problem: A city waterworks in southern Indiana had operated vertical turbine pumps for high and low service using eddy current drives from Dynamatic and another manufacturer. Motors were nominally rated at 200 and 500 hp, operating at 4,160 volts. The pumps, motors and drive units had operated successfully since 1980. After 33 years of service, the city engaged a consulting engineer to evaluate and specify rebuilding the pumps and replacing the motors, drives and motor control equipment.

Solution: The engineer evaluated replacing the eddy current drives with new 480-volt variable-frequency drives (with transformers to reduce the 4,160-volt supply) and low-voltage motors, versus direct replacement of the eddy current drives with new units and 4,160-volt motors. After considering costs, energy consumption and equipment longevity, it was a split decision: The 200 hp applications were redesigned for low-voltage VFDs, while the 500 hp high-service pump unit received a new DSI Dynamatic SPMV-8180, equipped with a high-efficiency 500 hp 4,160-volt motor and EC-2000 controller. To facilitate integration of the eddy current drive with the plant’s PLC-based SCADA system, the controller was equipped with an internet IP interface to enable the unit to exchange data and command signals digitally.

Result: The project was successfully started up in early 2016, and has operated as designed. 800/548-2169; www.dynamatic.com.

Related: Engineering, Consulting and Contracted Services

Highly loaded waste ponds become biogas banks

Problem: Uncovered anaerobic systems can generate significant odors in addition to methane. A Missouri project, believed to be the largest and most comprehensive livestock manure-to-energy system of its type in the world, is underway. The existing facultative basins collect waste from some 3 million hogs. The challenge was to convert more than 40 basins to covered anaerobic systems that would capture the biogas.

Solution: The earthen basins were covered with 80-mil linear, low-density polyethylene membrane covers from Industrial and Environmental Concepts (IEC). The airtight covers are sealed around the basin perimeters in an earthen anchor trench. A pipeline encircles the water’s edge to collect and channel the biogas to equipment on the berm that scrubbed and compressed the gas for use on site or to sell.

Result: The basins were upgraded with minimal disruption to the operation. The cover captured the biogas and contained the sulfides, significantly reducing hauling and pumping costs, as rainwater was excluded from the wastewater treatment facility. 952/829-0731; www.ieccovers.com.

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Delay coupling saves wear on gearbox bearings

Problem: The Eugene (Oregon) Wastewater Treatment Facility saw premature wear in the bearings of the gearbox connecting the motor to a double-flight Archimedean screw pump. Because a belt drive was used to transfer torque between a 200 hp motor and the gearbox turning a 90-inch-diameter, 63-inch-long screw, there was premature wear in the bearings. The lateral forces of the belt drive on the gearbox shaft created an unbalanced load.

Solution: Gregory Watkins, project manager for the city Wastewater Division, replaced the belt-driven system with Model MGD‑
18/250 delay couplings from MagnaDrive for four pumps.

Result: The city saw a 35 percent reduction in energy required to operate the pump, saving $34,831 per year. There was no wear on the bearings resulting from the lateral tension of the belts and virtually no maintenance after installation. The city also saw longer bearing life, as no vibration was transmitted between system components. “The initial price of the MGD was a little higher than other coupling technologies, but when we looked at the total cost of ownership over the life of our system, it was definitely the right decision,” says Watkins. 425/463-4700; www.magnadrive.com.

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