Firetube Vs. Watertube
Firetube Vs. Watertube
(OP)
We currently have 4 boilers that we are going to replace in one of our paper mills and our consultant has suggested 3 firetube boilers (120,000 lbs/hr total - I am thinking why not one boiler).
My question is - what is more efficient watertube or firetube and what about maintenance which is more costly to maintain/operate. Does anyone have any direct experience with these issues.
Thanks in advance...
My question is - what is more efficient watertube or firetube and what about maintenance which is more costly to maintain/operate. Does anyone have any direct experience with these issues.
Thanks in advance...





RE: Firetube Vs. Watertube
"I am thinking why not one boiler"? What are you going to do for steam/heat/power if you have to take your only boiler down for maintenance/repairs?
RE: Firetube Vs. Watertube
The paper mill goes down every 5 to 6 weeks for a few days and once a year for a week. A boiler is a static machine and I do not believe that we need a spare - however the plant would like one if they could. This is the secondary question - I am more curious if anyone has operating experience in terms of maintenance costs for both types of boilers and efficiency.
Thanks...
RE: Firetube Vs. Watertube
Many times, if you go with one large boiler, control valve, etc. you get into relatively short production runs, and the unit cost and delivery time takes a nasty jump.
While the boiler proper is essentially just a heat exchanger, there are LOTS of things to go wrong with auxiliary equipment like fans, controls, burner equipment, etc. If this was my plant, I'd be thinking a pair of 60's.
RE: Firetube Vs. Watertube
how do you cope with paper breaks do you have a dump condenser or do you dump to air do you have a small steam turbine ?
RE: Firetube Vs. Watertube
TBP gives you good advice,
You havent mentioned your boiler operating pressure....this would help us out an awful lot
Also, what is your miniumum steam demand ? Firetube boilers have excellent turndown
Firetube boilers are commonly avalable to 1000 bhp ( see www.johnstonboiler.com)
Operating pressures go to about 250 psig.....(depends on your selected size).....maximum steam flowrates go to about 34,000 lbs/hr
Firetube boilers are typically cheaper to purchase and quicker to deliver than watertube boilers
Download the DOE Steam Sourcebook for other details about the differences between these boiler types....
www.oit.doe.gov/bestpractices/steam/pdfs/steamsourcebook.pdf
let us know what you decide.........
(Where can we find these 40,000 lbs/hr firetube units !!??)
MJC
RE: Firetube Vs. Watertube
RE: Firetube Vs. Watertube
what fuel do you intend on using?
you can find fire tube (shell) boilers of upto about 80.000 lbs here at http://www.wellmanrobey.com/here
they also manufacture chp units (combined heat and power) or hrsg if you are american i belive this meens heat recovery steam generator
what are your enviromental requirements eg low nox burners and climate levey change tax ?
RE: Firetube Vs. Watertube
Thanks for all the info!
I have been working with a few contractors, our main contractor is pushing Firetube (Johnston) Claiming higher efficiency. From whay I can gather this is not true. He also has Firetubes slightly less expensive than Watertubes.
Our current demand is 80,000 lbs/hr and running 200# on the header. Our fuels is Nat gas.
Linux - I do not think we are heading for hsrg at this time.
TBP - Spares are nice I agree but we can not have a spare of everything. I am sure the plant would like a spare paper machine - but unfortunately that would not sit well with management! We have a few hundred combustions systems nation wide running almost 24/7 with minimal spares - we seem to do fine.
Thanks again for all you input!
RE: Firetube Vs. Watertube
Even if you don't care about having the load spread between 2 boilers, check price & delivery on a single large unit, vs a pair of 50% boilers. I've seen cases where a pair of half size components were a total of 70% of a single large one, and delivery time was literally cut in half.
RE: Firetube Vs. Watertube
RE: Firetube Vs. Watertube
Even if the installed cost of a pair of 50% units is the same as a single large one (and I'd be surprised if it's not measureably cheaper), I'll bet you can chop one to two months off the time line for this project by going with the smaller boilers.