Cement Americas

FALL 2017

Cement Americas provides comprehensive coverage of the North and South American cement markets from raw material extraction to delivery and tranportation to end user.

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www.cementamericas.com • Fall 2017 • CEMENT AMERICAS 21 FEATURE cutting edges to knock down accumulated material without damaging the silo's walls or support structure. Requiring no confined space entry, the device was set above the manhole opening at the top of the vessel and maneuvered by remote control. "Working together with the electrical and maintenance departments, we were able to continue operations during the cleaning process," Venegas said. "This really helped us avoid what could have been some costly downtime." Long-Term Prevention Once the silo had been completely evacuated, Brown – a flow aid specialist – realized that the ongoing problem could be remedied by utilizing Drake's current stockpile of air cannons. Using an innovative placement strategy, Brown was certain that the cannons could safely pre- vent buildup and promote efficient high-volume mate- rial flow, no matter how moist or dense the limestone. Rather than the two cannons at the bottom of the lime- stone silo firing across the cargo flow, five cannons were strategically placed around the vessel. Three 70-liter Martin Tornado Air Cannons were placed on the lower incline of the cone at a 30-degree down- ward angle against the 60-degree slope in the 6 and 12 o'clock positions (one side of the silo was inaccessible). In the 3 o'clock position, one air cannon was situated at the 2-ft.-wide shaft, and another was added to the upper silo to aid in loosening material. Already fitted with 53 XHV and Tornado Air Cannons throughout the plant, a programmable logic control (PLC) system centrally placed in the facility coordinates and monitors the timing and firing sequence of each unit at all locations, including the limestone silo. During the wet winter and monsoon months, the cannons are activated approximately every hour, but throughout the rest of the year the system has a firing sequence of only 4-5 times per day. This pattern can also be manually activated from the weigh feeder, at the solenoid panel or in the control room. Results Demonstrated by Production Gains Since installation, plant production has returned to normal levels. Material flow is ongoing, and the silo has not been shut down for cleaning. There has been no unscheduled downtime due to clogging, which has greatly increased production, especially through heavy weather periods. The use of CO2 tubes has been ceased altogether. When a buildup is detected, workers no longer are re- quired to get close to the area to resolve it, increasing plant safety and reducing the number of man-hours required to maintain the silo. "This equipment upgrade has paid for itself many times over," Venegas said. "We are extremely happy with the results. The service was fast, responsive and well coor- dinated. During our next scheduled outage, we're going to have a Martin Engineering team out here to consult on other areas where we might need air cannons, so that we can maximize production. We look forward to an ongoing and productive relationship." Information for this article courtesy of Martin Engineering. The lower silo cannons strategically placed around the 60-degree incline. Contractors installing the pipe nozzles at a 30-degree an- gle to promote material flow.

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