A major food processor in California installed a 150,000 lb/hr boiler in 1999 to help meet their increased seasonal demand. To meet low NOx regulations at the time, a high flue gas recirculation (FGR) burner and a large forced draft (FD) fan were installed for 9 ppm NOx operation.
To meet sub-10 ppm NOx requirements, the ultra-low NOx burner resulted in high FGR rates that often compromised the operational limits of the boiler equipment. These included limited turndown capabilities, flame pulsations, and unstable operation, and the unit could not properly follow the normal plant loads. The burner was also operating with high excess air (4.5% O2) resulting in poor efficiency. A solution was needed to improve boiler efficiency, provide a better operating boiler, and meet the newest air standards of 5 ppm NOx.
The existing boiler was upgraded with Nationwide's "Best Performance Standards" (BPS) boiler technology. The high FGR burner was replaced with a new low NOx burner that required no FGR and resulted in 10:1 turndown with low excess air operation (3%). New efficiency upgrades were also installed including an extended surface EconoStak economizer designed for maximum heat recovery. To meet NOx emissions a CataStak™ selective catalytic reduction system was installed to easily achieve 5 ppm NOx or less. The combination of the Econostak Economizer and CataStak SCR system is known as Nationwide Boiler's E2Stak.
The BPS solution provided immediate efficiency savings, emission compliance, and a quick return on investment. The burner upgrade decreased FD fan horsepower requirements by almost 200 HP and coupled with the EconoStak economizer, existing stack temperature was reduced by an additional 40°F, resulting in a 1% increase to the current boiler's fuel to steam efficiency. The immediate energy cost savings resulted in a utility rebate check of almost $150,000 to the end-user, offsetting the costs of the project.
The customer was more than satisfied with the overall performance of the system and commented that, "This was the first year we could operate the boiler in automatic!".
The yearly savings in both fuel and electricity further demonstrates how a BPS boiler upgrade assures that the latest efficiency gains and low NOx emission performance can be achieved.
Download this CataStak SCR and BPS Boiler Project PDF
| CUSTOMER PROFILE | EQUIPMENT SUPPLIED |
|---|---|
| Major food processor | Low temperature CataStak™ Selective Catalytic Reduction System |
| Located in the San Joaquin Valley Air Pollution Control District in California | Stack-mounted EconoStak economizer |
|
Received $150,000 rebate check at the completion of the project |
Low NOx burner with no FGR |
