Matrix Engineering (Paducah, KY) is an industry leader in petroleum coke conversion projects for lime recovery kilns in the pulp and paper industry. The shift in this niche industry to pulverized carbon powder fuel during the past decade has primarily been based on the lower price and very low price volatility of pet coke. Generally mills can negotiate longer-term contracts for the fuel and lower their dependence on natural gas and fuel oil. Because pet coke doesn’t share spontaneous combustive properties with other pulverized fuels, such as coal, it can be prepulverized and delivered to industry as a finished fuel ready to burn. This allows a mill to begin burning it with a low capital investment—a delivery system in lieu of building and maintaining a costly pulverizing facility.

In the fall of 2006, a leading North American coated paper manufacturer made the decision to convert one of its mills in the Midwestern United States to a pulverized pet coke burning system and chose Matrix Engineering as the provider of their fuel feed and delivery system. Matrix was awarded the complete turnkey contract for engineering, equipment supply, and installation of a single discharge silo and pet coke feed system capable of unloading both truck and rail. At the time, energy prices were high and the project was on an extremely tight schedule.

Matrix’s Densi-Feed system consisted of a storage silo with an unloading system for receiving and storing truck or rail deliveries of pulverized pet coke, an integral feed system for metering pet coke at a controlled and steady rate, and a pneumatic conveying system for transferring pet coke into a pneumatic line to the burner at the kiln.

The storage silo for the project was unique in that it required a design that would withstand high seismic activity. In addition, Matrix was committed to a stringent six-month turnkey delivery timeline from purchase order to burning coke. Matrix turned to storage expert Columbian TecTank, its partner from previous projects, to meet these challenges and provide a high-quality storage silo.

The Columbian TecTank silo installed for the project was factory welded at a height of nearly 90 ft and diameter of 14 ft. Manufactured at the company’s Winchester, TN, facility, the tank was capable of storing more than 8622 cu ft of dry bulk product. The silo was specially designed to withstand high seismic activity. It also featured an exterior spiral stairway, hopper, and loading/unloading system for truck and rail car. The interior did not require a coating, but the exterior coating selected was a proprietary shop applied baked-on coating designed to withstand fading and corrosion and to provide low long-term maintenance requirements.

Matrix and Columbian TecTank completed the project ahead of schedule, in less than six months, providing a significant cost savings in fuel for the manufacturing facility. Matrix credits its ability to provide both engineering and complete equipment supply—including tanks from Columbian TecTank—for shortening project times and allowing customers to see returns sooner. In this case, it allowed the pulp and paper mill to return more quickly to what it does best: manufacturing some of the most respected paper products in the industry.

Columbian TecTank is a global leader in the design, manufacture, and installation of factory-coated storage tank systems. The company has been in business since 1893, delivering more than 150,000 tanks to hundreds of different applications in over 125 different countries. For more information, visit www.columbiantectank.com.