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Show SEOUENCE START·UP AND FlOW RATE AND EMPERATURE AND PRESSURE PROTECTION SYSTEM BALANCE CONTROl MONITORING @~IR NATURAL GAS ~~--------~---~~~ AIR BLOWER 0 FLUE GAS -0 Figure 3. TEST SYSTEM OF THE UL TRA-LOW-EMISSION COMBUSTOR Because measurement protocol for combustion emissions is not standardized and the emissions being measured in the current studies are ultra-low, sampling and analysis of combustion gases were carried out very carefully. A water-cooled probe was used to sample the combustion products. The probe at the cold end was equipped with a section of externally heated stainless steel tubing to maintain a sample temperature of about 1900F so that moisture would not condense. The warm sample was passed through a millipore filter to remove any solid particles and a Permapure dryer to remove moisture. The dried sample was supplied to oxygen (02), carbon monoxide (CO), carbon dioxide (CO:V, nitrogen oxide (NO and NO,J, and total hydrocarbon (THC) analyzers through Teflon tubing. To ensure the accuracy of the measured emissions at ultra-low levels, all instruments were selected with appropriate operating ranges and calibrated before and after each test. The CO analyzer with a range of 0 to 50 vppm was calibrated by a 4.1-vppm span gas. The hydrocarbon analyzer with a range of 0 to 100 vppm was selected and calibrated by a 4.9-vppm span gas. The NO/NOx analyzer was ranged from 0 to 1 vppm and 0 to 10 vppm, respectively, and calibrated by a 3.3-vppm span gas. Because the NOx formation during combustion is comparable to that in ambient air, the NOx concentration in the combustion air was monitored before and after each test. The NOx content of combustion air was found to be from 0.08 to 0.25 vppm. Therefore, all NOx emission data have been corrected to a net increment through the combustion process. A suction pyrometer was used to measure gas temperature In the main combustor for evaluation of flame stability, as well as temperature uniformity. The sophisticated design and test system are for the purpose of extensive evaluation studies. A practical unit will be simplified Significantly based on the test results. 6 |
