Full-scale demonstration of low-NO(sub x) cell(trademark) burner retrofit: Addendum to long-term testing report, September 1994 outage: Examination of corrosion test panel and UT survey in DP&L Unit (number sign)4

摘要

As part of this DOE's demonstration program, a corrosion test panel was installed on the west sidewall of Dayton Power & Light Unit no.4 at the J. M. Stuart Station (JMSS4) during the burner retrofit outage in November 1991. The test panel consisted of four sections of commercial coatings separated by bare SA213-T2 tubing. During the retrofit outage, a UT survey was performed to document the baseline wall thicknesses of the test panel, as well as several furnace wall areas outside the test panel. The purpose of the UT survey was to generate the baseline data so that the corrosion wastage associated with the operation of Low NO(sub x) Cell Burners (LNCB(trademark) burner) could be quantitatively determined. The corrosion test panel in JMSS4 was examined in April 1993 after the first 15-month operation of the LNCB(trademark) burners. Details of the corrosion analysis and UT data were documented in the Long-Term Testing Report. The second JMSS4 outage following the LNCB(trademark) burner retrofit took place in September 1944. Up to this point, the test panel in JMSS4 had been exposed to the corrosive combustion environment for approximately 31 months under normal boiler operation of JMSS4. This test period excluded the down time for the April 1993 outage. During the September 1994 outage, 70 tube samples of approximately one-foot length were cut from the bottom of the test panel. These samples were evaluated by the Alliance Research Center of B&W using the same metallurgical techniques as those employed for the previous outage. In addition, UT measurements were taken on the same locations of the lower furnace walls in JMSS4 as those during the prior outages. Results of the metallurgical analyses and UT surveys from different exposure times were compared, and the long-term performance of waterwall materials was analyzed. The corrosion data obtained from the long-term field study at JMSS4 after 32 months of LNCB(trademark) burner operation are summarized in this report.