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To all gurus there,
We have four 7E frame Non-DLN along with 4 HRSG, making 600 supertheat steam (780 degree F+). Controller is Mark Vie. Denox steam is solely used for de-nox purpose (300 psig). Denox header has to come down for major repair for seven days. Our engineer has developed a plan for alternate denox mode. He made up a jump over from 600 header to 300 header IBL in one of the unit. This will be a try run to see if it works. There is no control over pressure and operator can manipulate glove valve (with relief valve downstream) to control the pressure and there is no desup to bring temperature down.
Right now denox temp is about 510F, but his plan demands straight use of 600 steam with temp 780+F. He talked to GE and per him there are no problems involved with GT hardware for this temp. Now my question why do Mark VIe has (L60STHT) height temp denox lock out? Which is set at 650F. So he plans to use 780F steam instead of normal 510F steam. I don't agree with him since there must be reasons for high temp denox lock out. My concern is combustion casing cover where 8 denox nozzles are located. this part is hot and barely cooled by CPD surroundings. I will use 780F steam instead of 510F steam for say 4 to 7 days. Controlling pressure would be tricky but once steady state reaches I think pressure is not an issue. Please advise me if temp is going to be a problem, if not then why do we have L60STHT trip for denox at 650F. I have great regards and hopes on this forum and anxiously waiting for any feed backs. Any feedbacks or insights are appreciated
We have four 7E frame Non-DLN along with 4 HRSG, making 600 supertheat steam (780 degree F+). Controller is Mark Vie. Denox steam is solely used for de-nox purpose (300 psig). Denox header has to come down for major repair for seven days. Our engineer has developed a plan for alternate denox mode. He made up a jump over from 600 header to 300 header IBL in one of the unit. This will be a try run to see if it works. There is no control over pressure and operator can manipulate glove valve (with relief valve downstream) to control the pressure and there is no desup to bring temperature down.
Right now denox temp is about 510F, but his plan demands straight use of 600 steam with temp 780+F. He talked to GE and per him there are no problems involved with GT hardware for this temp. Now my question why do Mark VIe has (L60STHT) height temp denox lock out? Which is set at 650F. So he plans to use 780F steam instead of normal 510F steam. I don't agree with him since there must be reasons for high temp denox lock out. My concern is combustion casing cover where 8 denox nozzles are located. this part is hot and barely cooled by CPD surroundings. I will use 780F steam instead of 510F steam for say 4 to 7 days. Controlling pressure would be tricky but once steady state reaches I think pressure is not an issue. Please advise me if temp is going to be a problem, if not then why do we have L60STHT trip for denox at 650F. I have great regards and hopes on this forum and anxiously waiting for any feed backs. Any feedbacks or insights are appreciated
