A Paper Industry Giant Upgrades Its Existing Scrubbers To Meet New And Future Pollution Control Standards

In order to meet new and future air pollution control standards a leading manufacturer of paper products has installed two Venturi scrubbers at their plant in Georgia. The units, installed by AirPol Inc. based in Parsippany, New Jersey, were needed to comply with new, more stringent EPD Air Compliance Regulations.

The company chose the turnkey Venturi system because it can be designed for practically any particulate emission level and can be upgraded to meet future regulations. Also, in the past AirPol has successfully installed several installations at the company's mills.

As part of an upgrade of their plant, the paper manufacturer was required to comply with new more stringent EPD Air Compliance Regulations for emissions from their No. 1 and No. 2 power boilers. These multi-fuel boilers burn an assortment of wood/bark, sludge, coal, tire derived fuel (TDF) and oil. The boilers produce approximately 500,000 lbs. of steam per hour each, and operate 24 hours/day, 350 days/year. To meet the new standards they decided to upgrade their two old AirPol scrubbers installed in 1974.

In order to meet the gas volume per boiler of approximately 450,000 ACFM at 390ºF, with a maximum particulate loading of 2,680 lbs./hr, AirPol provided two turnkey gas cleaning systems. Of particular concern was the ability of the systems to handle process gas volume fluctuations. Therefore, each Venturi was equipped with a double bladed large diameter adjustable throat Venturi scrubber, which ensures constant pressure drop to accommodate variations in flue gas volume. Also included was a cyclonic separator, exhaust stack and recycle tank. The project also included structural support towers, stairways, ductwork, instrumentation, demolition of existing equipment and installation, commissioning and start-up. A very aggressive project schedule was met and the final tie-in was on time and extremely smooth.

According to Jorgen Hedenhag, Sales Manager for AirPol, the advantage to the Venturi system is that it can practically be designed for any particulate emission level and can be upgraded to meet future regulations. "Due to AirPol's extensive data base for power boilers combined with emission testings before the final design, the required Venturi pressure drop could be established and later confirmed at a level that was much lower than for competitive systems," said Mr. Hedenhag.

The old system, installed in 1974, worked very well until the capacity of the two boilers was increased in the mid 1990's. The large increase in gas volume from the boilers caused excessive particulate emissions and increased stack opacity levels. However, the most annoying effect for the mill personnel was "raining" of dirty liquid droplets from the stacks. The purchase order for the new system contained a very strict limitation for liquid discharge from the stacks with performance guarantees.

"We gave this unconventional guarantee which has probably never given by any other company," said Mr. Hedenhag. Performance testing after start-up confirmed compliance and determined that no liquid droplets were being discharged from the stacks.

The system easily met and exceeded the State requirements for particulate emissions, not to exceed 0.28 lbs. per million BTU at maximum inlet (118.4 lbs./hr. at average inlet). Actual results were less than one third of allowable at very low pressure drop.