The Coffeyville Resources Nitrogen Fertilizer plant in Kansas has introduced new technology to overcome tracking, spillage and dust problems on two conveyors transporting petcoke.
The system was redesigned by Martin Engineering, with belt stabilisation and chute sealing technology, sensitive belt tracking equipment and heavy-duty primary and secondary belt cleaners. Operators have reported considerably less carryback, no tracking issues and a significant reduction in fugitive dust and spillage.
As a result, the only plant in North America to utilise petcoke gasification to produce hydrogen – a key ingredient in the manufacturing of ammonia and urea ammonium nitrate (UAN) fertilizers – estimates that the facility is saving more than US$14,000 per month in labour costs alone.
One of the primary issues that operations technical superintendent Marc Gilbertson wanted to address was material containment, to reduce the amount of dust and spillage that escaped from conveyors 19A and 19B, each 300ft long with a 24-inch wide belt. Travelling at 400 fpm (~2 mps), the belts carry an estimated 1400 tpd of petcoke to an entrained flow gasifier.
“We were seeing waist-deep piles accumulating each day, which required an average of about 90 man-hours per week to safely clean,” Gilbertson explained. In addition, the operation invested another 16 hours of equipment maintenance time each week.
Technicians first installed three Martin Impact Cradles, located under the belt in the loading zones. The cradle design features a bed of steel angles lined by energy-absorbing impact bars with a top layer of low friction, ultra-high molecular weight (UHMW) plastic.
After the impact zone, a series of 16 slider cradles were installed on each conveyor to stabilise the belt line and eliminate bounce. Designed for conveyor speeds up to 700 fpm (3.5 m/sec) and belt lengths of more than 50ft (15.2m), the units offer a flat and stable belt surface throughout the settling zone, reducing fugitive material and extending belt life.
Following the cradles, 20 Trac-Mount Idlers were installed on each conveyor. These rugged idlers have sliding frames on a stationary base that fits in tight spaces between belt support cradles for easy installation and service.
The system upgrade also included 90ft of modular chute wall. The pre-fabricated components make it easy to design and install transfer points and stilling zones to manage air flow and keep airborne dust inside. The components simply bolt together to reduce installation labour and replacement time.
To further improve containment, technicians also installed 184ft of ApronSeal Skirting System, which provides dual-seal efficiency with a single, one-piece sealing strip to prevent the escape of fines and dust. It incorporates a primary seal clamped to the steel skirtboard to keep lumps on the belt and a secondary or “outrigger” strip to capture any fines or dust particles.