Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
Steam Trap
- Thread starter Vaione
- Start date
Go here:
and read all the stuff highlighted in "Blue" in the middle of the screen.
and read all the stuff highlighted in "Blue" in the middle of the screen.
- Thread starter
- #3
They only call them steam traps. They are really CONDENSATE traps. Condensate forms in the steam lines, and does not contribute to the job the steam does. It erodes the piping, it puddles up and causes steam hammer, and condensate has about 1000 btu/lb less heat content than a pound of saturated steam.
Jim, they are "called" steam traps because they are meant to trap steam, and allow condensate to pass through ![[smile]](/data/assets/smilies/smile.gif "[smile] [smile]")
. I admit that some don't do this very well.
You also seem to have a jaded view of condensate (is there a bad experience there?) Think of the efficiency gains of trapping, I mean collecting, all that condensate and returning back to the boilers. I wouldn't be surprised if you receive a call from the Condensate Collection Society, in the near future.![[wink]](/data/assets/smilies/wink.gif "[wink] [wink]")
. I admit that some don't do this very well. You also seem to have a jaded view of condensate (is there a bad experience there?) Think of the efficiency gains of trapping, I mean collecting, all that condensate and returning back to the boilers. I wouldn't be surprised if you receive a call from the Condensate Collection Society, in the near future.
- Thread starter
- #6
And to think, I never dreamed I would ever enjoy a condensate conversation this much. When condensate is passed through the trap it can come through as a saturated liquid in which case some will flash off as the equilibrium with the downstream pressure is reached. That flash steam is typically lost. The remaining condensate is saturated and ready to put back into the boiler and become steam again with minimal heat addition. You have to heat the lost flash steam make up from its initial temperature to the saturation temp.
Some traps operate by sub cooling the condensate to reduce flash steam loss, but then there is a penalty to cycle efficiency for the heat required to bring the condensate back to saturation temperature so it can boil.
If you dump the condensate to the sewer then you lose all the condensate plus the heat to heat up the make up water to replace it.
rmw
Some traps operate by sub cooling the condensate to reduce flash steam loss, but then there is a penalty to cycle efficiency for the heat required to bring the condensate back to saturation temperature so it can boil.
If you dump the condensate to the sewer then you lose all the condensate plus the heat to heat up the make up water to replace it.
rmw
Yeah, I was going to make a similar comment about Jim's (jaded) post, but happy to leave it there. 
There are different types of traps for different purposes. Sometimes you want to remove condensate and keep headers dry, e.g. trapping condensate collection pots on headers, while other times you actually want tracing legs to remain filled with condensate, but only want to pass condensate below a certain temperature. The end goal is achieved by different traps and arrangements.
Steam trapping is a black art/science. The most common error I've seen young and ignorant players make is have a long uninsulated leg leading up to the steam trap. Um hellooo??? This leg is now a very efficient condensing leg resulting in bucket or thermodisc type traps working overtime just to remove this unecessary condensate. Maintenance costs go up or traps wear out and dollars dissappear in flash steam clouds.
The next most common error is made by maintenance engineers or stores managers trying to streamline the number of different types of trap designs and generally work towards installing one common design everywhere. *shakes head*
+1 on the benefit of recovering hot condensate.
- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."
There are different types of traps for different purposes. Sometimes you want to remove condensate and keep headers dry, e.g. trapping condensate collection pots on headers, while other times you actually want tracing legs to remain filled with condensate, but only want to pass condensate below a certain temperature. The end goal is achieved by different traps and arrangements.
Steam trapping is a black art/science. The most common error I've seen young and ignorant players make is have a long uninsulated leg leading up to the steam trap. Um hellooo??? This leg is now a very efficient condensing leg resulting in bucket or thermodisc type traps working overtime just to remove this unecessary condensate. Maintenance costs go up or traps wear out and dollars dissappear in flash steam clouds.
The next most common error is made by maintenance engineers or stores managers trying to streamline the number of different types of trap designs and generally work towards installing one common design everywhere. *shakes head*
+1 on the benefit of recovering hot condensate.
- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."
I am pleased that some of you found my comments colorful.
My points were that equipment designed to be heated by steam usually is less efficient when exposed to a steam/condensate mixture. Heat transfer is decreased in a partially-flooded device, and slugs of condensate moving at steam velocity can be destructive. It is important to separate the steam from the condensate, and condensate forms continuously because heat leaks through pipe walls, even when they are insulated.
For the sake of grabbing real numbers: 100 psi dry saturated steam carries an enthalpy of 1189 BTUs per pound. 338F. WIthout losing any temperature whatsoever, it gives up 880 BTUs and becomes saturated condensate with an enthalpy of 309 BTU/lb. THAT's a pretty efficient heat transfer medium. You can reclaim the condensate at (initially) 309 btu/lb, but removing one BTU from a pound of the condensate drops its temperature by one degree (round number). True, those ARE BTUs that have been paid for and they are worth recovering. MOST of the piping in a steam-cycle power plant is dedicted to recovering heat from condensate and pumping essentially saturated feedwater back into the boiler. It still takes a lot of BTUs to boil it, but it's better than starting with cold water.
Every steam trap vendor with which I have had contact offers surveys to inspect steam systems, identify problem areas and malfunctioning traps, and to increase efficiency/decrease heat loss of the system. The biggest obstacle to doing this is that the expenses come out of different budgets and accountability is indirect. If a supervisor spends $10,000 repairing/replacing faulty steam traps, that comes out of his maintenance budget. The resulting $20,000 decrease in fuel cost gets an attaboy for the supervisor at the steam plant. There is not always a recognition of the cause-effect relationship.
My points were that equipment designed to be heated by steam usually is less efficient when exposed to a steam/condensate mixture. Heat transfer is decreased in a partially-flooded device, and slugs of condensate moving at steam velocity can be destructive. It is important to separate the steam from the condensate, and condensate forms continuously because heat leaks through pipe walls, even when they are insulated.
For the sake of grabbing real numbers: 100 psi dry saturated steam carries an enthalpy of 1189 BTUs per pound. 338F. WIthout losing any temperature whatsoever, it gives up 880 BTUs and becomes saturated condensate with an enthalpy of 309 BTU/lb. THAT's a pretty efficient heat transfer medium. You can reclaim the condensate at (initially) 309 btu/lb, but removing one BTU from a pound of the condensate drops its temperature by one degree (round number). True, those ARE BTUs that have been paid for and they are worth recovering. MOST of the piping in a steam-cycle power plant is dedicted to recovering heat from condensate and pumping essentially saturated feedwater back into the boiler. It still takes a lot of BTUs to boil it, but it's better than starting with cold water.
Every steam trap vendor with which I have had contact offers surveys to inspect steam systems, identify problem areas and malfunctioning traps, and to increase efficiency/decrease heat loss of the system. The biggest obstacle to doing this is that the expenses come out of different budgets and accountability is indirect. If a supervisor spends $10,000 repairing/replacing faulty steam traps, that comes out of his maintenance budget. The resulting $20,000 decrease in fuel cost gets an attaboy for the supervisor at the steam plant. There is not always a recognition of the cause-effect relationship.
Jim, I hope you didn't take offence at my light hearted swipe. You sounded like you were having a really bad day.
Vaione seemed to be trying to get some understanding of what ... trapping, was all about. And the trap suppliers' sites contain a wealth of such info, as pennpiper highlighted. There is also much value for people such as Vaione in receiving detailed comments from experienced players in the field, to maybe reinforce some of the teachings, and avoid some of the traps.....
Vaione seemed to be trying to get some understanding of what ... trapping, was all about. And the trap suppliers' sites contain a wealth of such info, as pennpiper highlighted. There is also much value for people such as Vaione in receiving detailed comments from experienced players in the field, to maybe reinforce some of the teachings, and avoid some of the traps.....
- Thread starter
- #11
HEY JIM AND JOHN, I REALLY APPRECIATED YOUR COMMENTS AND I M REALLY SORRY IF I SAID SOMTHIN WRONG. I KNOW I WILL FIND BUNCH OF DETAIL FROM VENDOR'S SUTE BUT I FOUND THIS SITE'S PERSONS LIKE U AND JIM MORE HELPFUL. SEE I HAVE KNOWLWDGE ABOUT CONDENSATE TRAP TOO.. REALLY SORRY FROM JUNIOR ENGINEER TO SENIOR MOST PLAYERS.
Hey Jim, what specific application are you talking about?
Sometimes you do not want the temperature from saturated or dry steam to be transferred into a process. Steam tracing is a classic example of where you can make the most of the heat left in condensate and you can improve heat transfer using a transfer cement like thermabond.
You make a good point about slugs and hammer - that's why steam lines need to be properly designed to limit condensation and collect the condensate in ways that wont promote slugs.
Having good insulation in good repair is one often overlooked way at improving/maintaining the efficiency of steam delivery systems.
- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."
Sometimes you do not want the temperature from saturated or dry steam to be transferred into a process. Steam tracing is a classic example of where you can make the most of the heat left in condensate and you can improve heat transfer using a transfer cement like thermabond.
You make a good point about slugs and hammer - that's why steam lines need to be properly designed to limit condensation and collect the condensate in ways that wont promote slugs.
Having good insulation in good repair is one often overlooked way at improving/maintaining the efficiency of steam delivery systems.
- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."
Nope, Wasn't having a bad day, I just was trying to optimize the time I had on my lunch break. I regret if it came across as terse.
Thank you all for contributing, and for your constructive remarks. I know I benefit greatly from the multiple inputs, if only to realize I should watch how I phrase my comments so they are not misinterpreted.
I think we all helped Mr. Vaione with his dilemma. That's why this forum is here.
Thank you all for contributing, and for your constructive remarks. I know I benefit greatly from the multiple inputs, if only to realize I should watch how I phrase my comments so they are not misinterpreted.
I think we all helped Mr. Vaione with his dilemma. That's why this forum is here.
- Thread starter
- #14
Vaione, there are many steam expert crowds around who will audit your system and come up with recommendations.
There expertise comes into its own in regards to boiler operation, but the rest of it is not rocket science. Good and appropriate insulation, good and appropriate steam trap and repair leaks.
- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."
There expertise comes into its own in regards to boiler operation, but the rest of it is not rocket science. Good and appropriate insulation, good and appropriate steam trap and repair leaks.
- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."
- Thread starter
- #16
The most common (and irritating) mistake I have seen made in steam / condensate trapping installations (especially thermodynamic Y-pattern like - for example - Yarway 721) is putting them so close together so that when you make the final connections in the manifold there suddenly is no room to screw them out for maintenance / replacement, so you end up having to cut them out with a torch.
I don't know how we (engineers and piping construction contractors) accomplish installing them that way...but between the two of us, we somehow do.
Regards,
SNORGY.
I don't know how we (engineers and piping construction contractors) accomplish installing them that way...but between the two of us, we somehow do.
Regards,
SNORGY.
- Status
Similar threads
- Locked
- Question
