OCR Text |
Show emissions of N O x and CO. Figure 1 is a photograph of the R S B burner during normal operation, showing the radiant and blue-flame zones of the burner when fired. Recent progress in the commercialization of the RSB is presented in the following sections. Results of full-scale industrial boiler field tests are summarized in Section 2. These results led to the first commercial sale of the R S B with a 9 ppm NOx guarantee, and this installation is described in Section 3. A summary of the current status of the commercial development of the R S B is presented in Section 4. 2. SUMMARY OF FIELD TEST RESULTS The RSB was originally developed for use as a 30 ppm "non-FGR" low-NOx burner for oil field steamers, but its application was limited due to the necessity of operating at approximately 30 percent excess combustion air to achieve the desired N O x level without FGR. In order to lower stack 0 2 levels and obtain a higher efficiency system, F G R was selected as the appropriate N O x reduction strategy based on sub-scale testing. The goal of field tests completed in 1997 was to demonstrate the use of F G R in a full-scale R S B with N O x emissions below 9 ppm, C O emissions below 50 ppm, stack 0 2 below 3%, and F G R levels under 30%. These goals were achieved at several test points in a 62.5 MMBtu/hr (18.3 M W J oil field steamer used for demonstration and data acquisition. The test boiler was a Struther's oil field steamer and consisted of a 9 ft (2.7 m) diameter, 37 ft (11.3 m ) long radiant section lined by 3 inch (76 m m ) diameter tubes placed on 6 inch (152 m m ) centers. A convective section follows as the flue products turn upward toward the exhaust stack. The R S B installed in the steamer had nominal active burner dimensions of 30 inch (762 m m ) O D by 105 inch (2.67 m ) length, and was installed on the boiler front wall. A 12 inch (305 m m ) F G R line connected the boiler exhaust to the fan inlet. A butterfly valve was used to control the percentage of induced FGR. Typical exhaust temperatures (inlet to the F G R piping) were 330 °F (165 °C) and typical F G R temperatures at the butterfly valve were 260 °F (127 °C). The burner was operated over approximately a 3:1 turndown range with the majority of the data collected at half to full load for the burner as configured. NOx 2 |