OCR Text |
Show The furnace observations showed that the superheaters had somewhat more deposits for the Pocahontas coal, but below the superheaters, the furnace was more clean with Pocahontas and the deposits appeared to be thinner and lighter. Additionally, both coals created eyebrows, but the eyebrows from the Pocahontas coal were thinner and more molten. The measurement of FEGT with the PSIT OTM is presented in Figures 3 and 4. In Figure 3, the temperatures measured for Alpine coal are displayed. During the 6-hr period displayed, all four burner rows were operating and the furnace load was 157 MWe. As can be seen, a number of temperature cycles were observed. Essentially, the temperature rose from about 2400° to 2550°F; this period was followed by use of some of the IR sootblowers resulting in an immediate drop in FEGT. The sootblowing activities recorded in the control room logbook are indicated by the crosses on the figure. In addition to correlation with the occurrence of sootblowing, the temperature cycles also correlated with the amount and location of sootblowing. For example, the 150°F drop in temperature between 17:00 and 18:00 resulted from the use of six IR sootblowers on the North side (#13, 14,21,22,23, 24) which were located in the middle furnace section where deposits were the highest. The small, 50°F, drop in temperature which occurred between 18:00 and 19:00 corresponds to engaging two IR sootblowers in the upper region of the furnace (# 31,32) where the walls were relatively clean. The data in Figure 3 give an accurate representation of the observations at full load and with all four burner rows in service with baseline coal. Observations were also made when the next to highest burner row was taken out of service and full load attained with the other three rows. In this case, there was an immediate drop in FEGT of 100°F during the transition. This large drop was due to a momentary drop in load. After a few minutes the FEGT recovered somewhat and stabilized at about 60° to 80°F lower than the baseline. 2700~---------------~--------------------~---------------~--------------------~---------------~~---------------~ .--u . 2600 + + Q) + + ~ .:.:.:.J. C"d 2500 ~ Q) a. E Q) t- 2400 I + Blow Soot 2300 .' 16.5 17.5 18.5 19.5 20.5 21.5 22.5 Time (24 hr) 1: 8-6791 Figure 3. FEGT Measurements at Salem Harbor #3, Baseline Coal 7 |