Eng-Tips is the largest engineering community on the Internet
Intelligent Work Forums for Engineering Professionals
-
Congratulations waross on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
Copper in Feedwater
- Thread starter GBurns
- Start date
i would concur; however, i not an expert either. copper would likely accummulate in the boiler, which is not good!
suggest investigating the source of copper (i.e. exchanger tubes), isolate that source, and then apply corrective measures.
try the abma (american boiler manufacturer's association) web site or conducting a web search for boiler feedwater+copper and you will likely get positive responses.
good luck!
-pmover
suggest investigating the source of copper (i.e. exchanger tubes), isolate that source, and then apply corrective measures.
try the abma (american boiler manufacturer's association) web site or conducting a web search for boiler feedwater+copper and you will likely get positive responses.
good luck!
-pmover
Copper deposits in boiler can result in pitting corrosion, very similar to that caused by dissolved oxygen. At the pressures you're talking about, is the source of the copper a condenser under a steam turbine? If it is, are you using a water treatment program that can result in low levels of ammonia in the condensate? Ammonia + copper = bad news.
- Thread starter
- #5
billblackwellpe
Mechanical
The copper will deposit on the waterside of your boiler tubes causing overheating and tube failure. Once this happens you have to chemically clean your boiler. The copper gets in the feedwater from condenser tubes and feedwater heater tubes when there is oxygen in the feedwater. You can feed chemicals to remove the oxygen.
Bill Blackwell, P.E.
Bill Blackwell, P.E.
If you are experiencing copper transport, you'll need to look at several items:
1) if it is carrying over to the boiler, usually your chemical supplier will be able to analyze tube samples and advise whether you are a candidate for a boiler chemical cleaning... he'll tell you where and how big a sample you'll need to cut out... it's usually in the section of the furnace that sees the highest heat flux... copper deposits will reduce heat transfer and also provides cells for corrosion as indicated in the other postings...
2) check your cycle chemistry: the source is either your condenser or low-pressure FW heaters where Admiralty brass tubes are used... check for ammonia at your vapor extractors (SJAE of vacuum pumps)(this is usually from the breakdown of your oxygen scavenger, too much gives lots of ammonia)
3) check the intermidiary tube sheets at the tube penetrations right below your exhaust for signs of ammonia attack -- may need to keep track of these for tube failures
4) another area of concern is the hp and crossover heaters although at the boiler pressures you mention, these may not be significant -- the copper plates out in areas of high heat flux, I have seen where the copper in the feedwater has plated out on the inside of the tubes in these heaters reducing the heat transfer -- this copper will shed like snake skin when trying to do normal tube cleaning -- it pillows up (usually near the U-tube section and will plug up the tube) -- you will not get these out without replacing the tube... you may need to look at chemical cleaning the tube side of the feedwater heater rather than normal means of cleaning)...
so, excessive copper can give you headaches, even nightmares -- your best preventios are training the operators to keep your cycle chemistry within the desired ranges at all times -- and solicit the experience of your chemical supplier; they should be able to tell you if your copper loading is liveable or it needs addressed in the near term...
best wishes..
1) if it is carrying over to the boiler, usually your chemical supplier will be able to analyze tube samples and advise whether you are a candidate for a boiler chemical cleaning... he'll tell you where and how big a sample you'll need to cut out... it's usually in the section of the furnace that sees the highest heat flux... copper deposits will reduce heat transfer and also provides cells for corrosion as indicated in the other postings...
2) check your cycle chemistry: the source is either your condenser or low-pressure FW heaters where Admiralty brass tubes are used... check for ammonia at your vapor extractors (SJAE of vacuum pumps)(this is usually from the breakdown of your oxygen scavenger, too much gives lots of ammonia)
3) check the intermidiary tube sheets at the tube penetrations right below your exhaust for signs of ammonia attack -- may need to keep track of these for tube failures
4) another area of concern is the hp and crossover heaters although at the boiler pressures you mention, these may not be significant -- the copper plates out in areas of high heat flux, I have seen where the copper in the feedwater has plated out on the inside of the tubes in these heaters reducing the heat transfer -- this copper will shed like snake skin when trying to do normal tube cleaning -- it pillows up (usually near the U-tube section and will plug up the tube) -- you will not get these out without replacing the tube... you may need to look at chemical cleaning the tube side of the feedwater heater rather than normal means of cleaning)...
so, excessive copper can give you headaches, even nightmares -- your best preventios are training the operators to keep your cycle chemistry within the desired ranges at all times -- and solicit the experience of your chemical supplier; they should be able to tell you if your copper loading is liveable or it needs addressed in the near term...
best wishes..
- Status
Similar threads
- Locked
- Question
- Locked
- Question
- Locked
- Question
- Question