The Challenge:
When a business has an energy bill in the tens of millions of dollars, even small decreases can add up to big savings. Such was the case at Verso Paper’s Androscoggin Mill in Jay, Maine. With an oil bill on their lime kiln approaching $30 million dollars a year, Verso contacted ETTER Engineering to help with an oil-to-gas conversion. When ETTER was finished, Verso’s fuel costs for that single piece of equipment had been cut by nearly two-thirds. That’s real money!
The Solution:
After consulting with the paper mill’s on-site engineering team, ETTER drew up plans for two separate pieces of equipment – a pair of indoor Valve Rack systems (one for each of the two lime kilns), and a Main Regulator Heating Station for exterior roof top installation. This allowed the paper mill to move to less costly natural gas by taking delivery right off the utility’s high pressure pipeline. The challenge with the application was not just regulating the pressure, but also ensuring the temperature of the gas delivered to the burner stayed within an acceptable range. With a nominal 500 PSIG supply and a pressure at the kiln’s burner of 20 PSIG, the 480 PSID of differential pressure drop resulted in a 30° to 35°F drop in the temperature of the gas. Coupled with an exposed above-ground pipeline, the 167,000 CFH of natural gas being supplied was certainly going to be delivered cold, especially in the dead of winter in Maine! So cold, in fact, that freezing of critical equipment such as gas regulators would plague the project unless additional measures were implemented.
ETTER’s job was to temper that gas throughout the year automatically as the temperature, mass flow rate and conditions changed. “Regulating a gas stream’s pressure is relatively easy, the finesse in this project was to control temperature of the fuel along with its pressure to the kilns in order to maintain reliable and consistent burner operation,” said Jon Moore, Vice President of Engineering Sales at ETTER. After working with oil burners for decades, the kiln operators were pleasantly surprised at the ease of operation with the new fuel. Management was pleased to see the significant cost savings happen in the first month of operation. This project was extremely successful, delivering both the cost savings as well as a robust solution that will bring years of reliable operation!
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