COOLflow™ Case Study 114

Smurfit-Stone Pulp and Linerboard Mill in New Richmond, Quebec

The Situation

The Canadian Province of Quebec has implemented legislation that will ensure improved air quality standards within the region. To comply with the recent legislation, the Smurfit-Stone Pulp and Linerboard Mill located in New Richmond, Quebec, was required to lower particulate emissions in Power Boiler No. 1 to 60 mg/GJ. After researching the available low-emission technology, Smurfit-Stone concluded the most cost-efficient and proven solution for compliance was to perform combustion airflow modeling and then install burner upgrade kits.

The Boiler

Smurfit-Stone’s Power Boiler No. 1 is a Combustion Engineering tangentially-fired boiler that fires bunker C heavy fuel oil. The designed production rate is 375,000 lb/hr of superheated steam at 625 psig and 750° F. The unit has eight burners arranged one over one in each of the four corners. An imbalance resulted in a deficient amount of combustion air through one or more of the burners in the upper row. Consequently, the flame geometry was uncontrolled, combustion efficiency was poor and particulate discharge was too high. To compensate, the boiler operated with only four burners in service for an extended period of the total operating time.

The TODD® Solution

In June 2000, John Zink Company’s TODD Combustion Group visited the Smurfit-Stone Mill to assess the situation and advise of potential solutions. A site inspection of the boiler in its operating mode confirmed that the poor combustion performance was primarily due to the serious airflow imbalance and outdated fuel-oil atomizing techniques. A three-phase plan consisting of both COOLflow™ and COOLkits™ technologies was recommended to treat both conditions that were contributing to the higher than normal opacity and flame instability.

First, COOLflow modeling techniques were used to create a physical airflow model. The physical model was then used to determine existing airflow patterns and design the necessary solution. This consisted of air deflection baffles and turning vanes that were installed in the wind boxes and ductwork systems during the fall maintenance outage. After the modifications were made, a stack emission test was performed to verify that the airflow modifications were successful. Phase three involved installation of COOLkits with state-of-the-art, low-NOx oil atomizing equipment. COOLkits, which entail installing custom-designed burner components into existing air registers, are a low-cost solution to reduce emissions.

The TODD Result

The COOLflow model and associated engineering drawings were completed by October 2000. During the November maintenance shutdown, the boiler’s combustion air system was modified according to the COOLflow results. The installation went as planned, and the boiler started up on schedule.

The phase-two, stack emission tests were completed in early December. The Provincial Permit allowed a particulate discharge of 60 mg/GJ fired, and the test results confirmed that the COOLflow modifications alone had reduced particulate emission below that level. Although the COOLkits modifications were not required to comply with particulate emission requirements, mill experts are still considering the COOLkits modifications for increased emission reductions.

Particulate Discharge Emissions
Pre-modification average 80 to 85 mg/GJ
Post-modification average 35 to 40 mg/GJ

The COOLflow solution delivered several additional benefits.

  • Eliminated unwanted tramp air and air leakage
  • Improved mass flow and air distribution from +32.8% to +3.8% between all eight burners
  • Eliminated detrimental swirl of airflow entering each burner’s register
  • Improved and balanced the airflow velocity at the peripheral inlet of each register from +100% to +13.2% of mean
  • Enabled lower excess O2 operation