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Show TEST FACILITY AND PROCEDURE FM Boiler All tests were conducted using a Babcock and wilcox 50 MBTU/hr capacity, industrial boiler shown in Figure 1. The furnace is a bottom supported, forced draft fired system with the interior dimensions of 20'8" x 6'4" x 8'6". Rows of carbon steel tubes are used in the water wall construction and the convective pass 2 section of the boiler, providing a total heating surface of 4410 ft . Residual fuel oil (0.2% fuel-N) was pumped from a fuel bunker and heated to about 200°F by electric and steam heaters. Fuel atomization was achieved by an 8-hole T-jet atomizer placed in the center of a B&W circular burner. Combustion air was supplied to the burner through eight adjustable swirl vanes with 18 settings from fully closed to wide open. Gas Sampling and Analysis System Stack gases were sampled continuously at 50 feet downstream of the boiler outlet and were filtered and dried before reaching a standard set of gas anal¥zers. Concentrations of CO and CO2 were measured by Beckman nondlspersive infrared analyzers. NO (NO + N02 ) were measured by a Thermoelectron chemiluminescent N5 analyzer equipped with a stainless steel N02 to NO converter. Oxygen was measured by a Beckman paramagnetic analyzer. The analyzers were calibrated using certified gas standards. Opacity Measurement System A Lear Siegler (Model RM 41) optical transmissometer provided a qualitative measurement of the discharged particulate matter from the stack. The instrument operates in the 0.4-0.7 ~m range and uses a double pass beam with a total path length of 8 feet. Temperature/Gas Sampling Probe Furnace temperature was measured by a 75 inch-long highvelocity- thermocouple (HVT) probe. The thermocouple (ChromelAlumel, type K) was shielded by a short refractory tube to minimize radiation losses and was housed inside a water-cooled gas sampling probe. Cyanuric Acid Delivery System Coarse cyanuric acid crystals from two different manufacturers were purchased at a local distributor. One brand (BioGuard) was composed of 100% cyanuric acid; the other (Swim Free) had a purity of 80% with a 20% elemental balance of sodium, oxygen, carbon, and hydrogen. Each batch was ground separately into a fine powder. Large particles were sifted through 16, 30, and 50 mesh screens. Smaller particles (~300 ~m) were measured by a laser-based Microtrac particle size analyzer (Model 7991-1). Figure 2 shows the size distribution of the representative samples. A calibrated variable-speed screw feeder discharged the pulverized acid to an aspirator (Figure 3), where it was dispersed and mixed with air and finally sprayed into the furnace through an injector (Figure 4). Eductor and suction air flow rates for the -3- |