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Boiler Commissioning at South Carolina Paper Mill a Success

Case Study

  • Company: South Carolina Paper Mill
  • Industry: Manufacturing
  • Location: South Carolina
  • Profile: The 700+ ton/day facility recycles old corrugated containers and mixed papers to produce both corrugating medium and linerboard.
  • Challenge: The facility's 45,000 lb/hr existing boiler had become lethargic in the way it handled the process load, sacrificing reliability.
  • Solution: The facility purchased a new 82,500 lb/hr, natural gas-fired Cleaver-Brooks Nebraska D (CBND) boiler system with condensing economizer and NXT burner with Hawk controls.
  • Results: The CBND’s performance has exceeded expectations, running at 87% efficiency; that is a 15 to 18% increase over the facility’s previous boiler, and 4 to 5% greater than many industrial watertube systems.

 A paper mill located in Upstate South Carolina operates a high-performance linerboard mill. The 700+ ton/day facility recycles old corrugated containers and mixed papers to produce both corrugating medium and linerboard in a wide range of weights to suit its customers’ needs.

In 2011, mill management decided to invest in a new boiler to increase production and plant efficiency, as well as maximize profitability by mitigating future relability issues. Its 45,000 lb/hr existing boiler had become lethargic in the way it handled the process load. For instance, when a sheet broke, the boiler was very slow to respond. It would overpressurize the header system and release steam into the atmosphere. They desired an efficient new boiler that would automatically respond to this situation, instead of venting steam to atmosphere thereby impacting their bottom line.

The mill approached C&C Boiler Sales & Service, a Cleaver-Brooks authorized representative headquartered in Charlotte, N.C., about replacing the boiler system. Jon Craig, president of C&C Boiler, suggested the facility purchase a new 82,500 lb/hr, natural gas-fired Cleaver-Brooks Nebraska D (CBND) boiler system with condensing economizer and NXT burner with Hawk controls.

The client placed an order for a new CBND in March 2012, and the unit was delivered by October 2012. C&C Boiler handled the commissioning without any interruption of production at the facility. According to John Luzon, Technical Solutions Leader for C&C Boiler, the installation and start-up was completely in their scope. C&C removed the old boiler, put in the new one and commissioned it within four weeks.

“This is one of the smoothest running package boilers that I’ve seen,” said Luzon. “I’ve managed a diverse range of Nebraska boiler projects along with other OEM manufacturers and this one was executed safely, seamlessly and on schedule. In fact during commissioning of the Natcom burner, which was completed by C&C Boiler’s factory-trained technicians, no issues were encountered. Boilers usually don’t come out of the box like that.”

The CBND’s performance has exceeded expectations, running at 87% efficiency. That is a 15 to 18% increase over the facility’s previous boiler and 4 to 5% greater than many industrial watertube systems. Luzon notes that one of the reasons the CBND’s efficiency is so high is because it has a Cleaver-Brooks two-stage condensing economizer on it, which recovers sensible and latent heat from the stack flue gases before it is discharged to atmosphere. Another enhancement includes state-of-the-art Hawk controls outfitted with parallel positioning, O2 trim and a VSD drive.

The boiler is designed to respond to changes and adapts well to variations in the cyclical loads of the paper machines. Unlike the previous boiler, the new CBND responds immediately to non-predictive situations such as a sheet breaking. As a result, the boiler is saving the plant additional money in that regard.

The Mill’s new boiler has met or exceeded all of the emissions requirements as well. It met NOx requirements of less than 30 ppm corrected to 3% O2, and is well below the CO requirement of less than 50. Based on 10:1 turndown, the boiler also met the O2 requirement.

In addition, the operators are pleased with the system’s user friendliness. The 10” touch screen display on the Hawk controls is straightforward and easy to navigate. The controls were designed to communicate with the customer’s Allen-Bradley DCS. The paper mill has three remote capabilities to write to Cleaver-Brooks PLC – one is a remote set point for boiler pressure, one is a feedwater control valve and the third is remote shutdown. According to Luzon, “Everything worked very well. The Hawk controls homogeneously integrated with the client’s DCS and performed as well, if not better than expected.”

C&C Boiler trained the 40-person operations team at the Mill to do preliminary start-up, re-occurring maintenance and basic troubleshooting, and Luzon has written several manuals, job safety analysis and standard operating procedures. According to Luzon, the scope of the project required comprehensive training, and this is a distinct advantage of C&C Boiler and the Engineered Boiler Systems divisions of Cleaver-Brooks. He continued, “We routinely offer customized, thorough training for facility personnel to safely operate and maintain their equipment."

As far as the overall project, Luzon stated, “I’ve completed quite a few of these installations, and was very impressed with the safe implementation of our Cleaver-Brooks industrial watertube boiler and burner equipment solutions.” Jon Craig summarized, “What impressed me more than anything was the boiler flue gas outlet temps were in the mid 550°Fs and left the two-stage economixer just above 200°F."