Extracting bundle of floating head heat exchanger
Extracting bundle of floating head heat exchanger
(OP)
Dear All,
we are facing the problem that we can't remove the bundle of our horizontal shell&tube heat exchanger. Weight of bundle is 9t. Design floating head (drawing attached).
Problem: hx has severe fouling and is leaking. Leaks are expected to be caused by uneven thermal expansion due to debris collected between the baffle plates and reducing heat transfer (pic), mechanical stress as we have non corrosive fluids (hydrocarbons).


Assumed reason that bundle stuck in the shell:
Solids (coke) has has settled down at the botom of the shell between the baffle plates (high and tolerance of baffle plates to shell is to small. Bundle can't be moved at all.
We tried to pull with 16 t forklift, used hydraulic jack at floating end to push it and to break it loose - no success. There might be also a deformation of the shell due to uneven heat distribution since we expect a lot of residue (coke - pic is from different unit) has settled at the bottom so free tubes have a different thermal expansion than the covered tubes.Chemicals doesn't work as coke is quite inert to most common used chemicals
We will try once again with larger hydraulic jacks to break the bundle loose and then pull (see right side of marked drawing). If that fails we will need to cut the shell. Red marked cutting of a window is not suitable acc to the vendor as the shell will collapse once the section is welded back (heat impact and shrinking - many attempts failed with other clients). They agreed to follow the green marked strategy to cut the shell in 3 pieces. But even then rewelding will be a challenge. Please note that only the pic with tubesheet (leaks) is the particular unit. The other pics are from an other unit but we were able to extract the bundle. Any suggestion? Thanks in advance
we are facing the problem that we can't remove the bundle of our horizontal shell&tube heat exchanger. Weight of bundle is 9t. Design floating head (drawing attached).

Problem: hx has severe fouling and is leaking. Leaks are expected to be caused by uneven thermal expansion due to debris collected between the baffle plates and reducing heat transfer (pic), mechanical stress as we have non corrosive fluids (hydrocarbons).


Assumed reason that bundle stuck in the shell:
Solids (coke) has has settled down at the botom of the shell between the baffle plates (high and tolerance of baffle plates to shell is to small. Bundle can't be moved at all.
We tried to pull with 16 t forklift, used hydraulic jack at floating end to push it and to break it loose - no success. There might be also a deformation of the shell due to uneven heat distribution since we expect a lot of residue (coke - pic is from different unit) has settled at the bottom so free tubes have a different thermal expansion than the covered tubes.Chemicals doesn't work as coke is quite inert to most common used chemicals
We will try once again with larger hydraulic jacks to break the bundle loose and then pull (see right side of marked drawing). If that fails we will need to cut the shell. Red marked cutting of a window is not suitable acc to the vendor as the shell will collapse once the section is welded back (heat impact and shrinking - many attempts failed with other clients). They agreed to follow the green marked strategy to cut the shell in 3 pieces. But even then rewelding will be a challenge. Please note that only the pic with tubesheet (leaks) is the particular unit. The other pics are from an other unit but we were able to extract the bundle. Any suggestion? Thanks in advance
RE: Extracting bundle of floating head heat exchanger
Let you try ultra high pressure cleaning , you can use the nozzles at the bottom of the HX to introduce the gun and the hose.
Pierre
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
Can you remove the whole thing or at that second set of flanges?
Can you drill as et of 1" holes and add screwed in nozzles to jet out coke or maybe even a set of say 4" coupons to get some mechanical cleaners in there. if you do this just in front of where the tube supports / baffle plates are would be a good place to start.
Flood the shell with lubricating oil (thin) and let it soak in for a while?
whatever you do please let us know how it goes - looks errr "interesting".
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
Btw. I was thinking of putting it vertically on the tube sheet and pull the casing like a sleeve just to break it loose. But it is also an expensive job as eqipment etc is difficult to get here in Batam island. It is also not the safest way to stand it up.
This was second attempt with tightening the strut bolts and press it into the shell (from floating end). 4x4 was bent and we used small hydraulic jack....Failed
This is a leak and it looks tube is torn on the circumference about 270 Deg. Th end shows the coke blocking the tube. Please note, this is 25.4 x 2 mm SA179 and we hv no corrosive fluids and pressure is below 6 bar.
So it can only be thermal stress due to expansion problems ..
RE: Extracting bundle of floating head heat exchanger
Then hammer the daylights out of what is now the roof? Basically use its own weight to peel it off the surface just enough to pull it out?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
It probably is a mechanical fit issue, but worth a try to use its own weight to free it from the surface tension and adhesion.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
I suggest that you perform a cost study and contact a TEMA fabricator about a complete HX replacement or retain the channel and consider a replacement of only the bundle and the far side head
If you are forced to chose between replacement of the entire bundle or performing extensive tube cleaning, replacement and repair, then the cost of complete replacement may not be much different.
Bundle replacement also has the benefit and peace of mind of a brand new unit and the assurance that you will not find yourself in the same clogging predicament a year of two from now!!
There may also be some benefits from some design improvements made to a replacement unit (larger tube spacing or a different tube pattern ?) Perhaps even some ports added to the shell for periodic spray clean out ??
Oooops ... I forgot .... your boss just said that there will be no HX replacements !!! ..... Why ?.... Because there is no money in the budget and he said so !!!
Please keep us in the loop and tell us of your final fix
MJCronin
Sr. Process Engineer
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
Such equipment is not available here especially during covid logitic also difficult.
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
Yes new unit but..........as you know
pipe material from Japan, Korea or Europe 2-3 months ex works
building it 3 months...........No budget ..no time either. So need to get plant running by repairing and replace unit asap.
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
Red tubes are blocked and need manual drilling. Hydrojetting 15000 psi cant get it out
1. pass is solvent vapor in tubes - 2. pass is condensate (last 4 bottom rows).
Will take another week to get it cleaned in the tube side.
RE: Extracting bundle of floating head heat exchanger
Are there any higher hydrojet pressures available on your island? 15,000 psi is low for hard, asphalty deposits. I’m not surprised it is ineffective. You would be better served with 40k, preferably 55k lancing.
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
Yes, we use 20k and 40k regularly here for cleaning polymer reactors and Hx tubes. Pressures below 13-15k barely do anything to clean hard polymers off the metal surfaces. The cleaning is done by a professional external company - I do not recommend you taking a "do it yourself" approach when using high pressure water cleaning that is outside your normal area of expertise.
I’ve also used 55k to clean a styrene storage tank - polystyrene buildup is as hard as a rock and chips away like glass. That was cleaning with a hand-operated wand, though - I’m not sure if Hx cleaning is done with 55k.
Ultimately, I think MJCronin is right. I wish you the best, but you I suggest you start collecting design data/quotes for a new unit.
RE: Extracting bundle of floating head heat exchanger
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
RE: Extracting bundle of floating head heat exchanger
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
Please respect us by keeping us in the thread and leaving information that others will benefit from
Thank you and Best Regards ....
MJCronin
Sr. Process Engineer
RE: Extracting bundle of floating head heat exchanger
luis
RE: Extracting bundle of floating head heat exchanger
Already considered but as the 16 t forklift did not work at all, the 9 t bundle will not help much especially crane costs USD 2000/day
I will go with hydraulic jack 50 t and support-frame and will push it from the floating head side. Once it can be moved 100-200 mm then we can pull it. But anyway....this is just the beginning. We will have to clean the bundle and investigate the cause of the leaks (so far 23). Anyone has an idea what can cause such leak as shown in pic? Pressure not exceeding 9 bar. Tubes are 25.4 x 2 mm SA 179
This is just 1 pic with left side large hole.
I am still thinking of mech. stress due to uneven thermal expansion but side walls are looking like overpressure inside of tube. Also leaks happened almost same time. Problem was only recognized when level of 1. column could not be maintained but level of 2. column increased. That indicated the leakage of more than 1 0r 2 tubes. (Still need to check trends which might identify wrong operation)
RE: Extracting bundle of floating head heat exchanger
luis
RE: Extracting bundle of floating head heat exchanger
Consider to contact Uraca Indonesia ,they should be able to give you a contact (contractor)
https://www.uraca.com/en/contact/sales-worldwide/
Another Link : http://sbsindonesia.com/products/equipment/
Not far you may consider to check with Singapore .
Sore
Pierre
RE: Extracting bundle of floating head heat exchanger
Right now all is difficult since we were unable to generate revenue since 2 years. We are bleeding due to some design faults.
RE: Extracting bundle of floating head heat exchanger
Lesson learnt. Keep 3 mm gap between shell and baffle plate. At least if you run with products which require regular cleaning of shell side.
RE: Extracting bundle of floating head heat exchanger
1. Pulling didn't work so I decided to push it out with a 100t hydraulic jack
2. Built a structure with a 20 mm plate to protect the tube sheet, and a reinforced 24 mm plate as counter part.
3. Used 8 long stut bolts to balance the forces on the shell flange
5. Welded a support on the plate to support the 30 kg jack
6. Installed marker for the progress of movement
7. ....starting pumping up. Once the pressure was to high the bundle made a 20mm jump and was freed.
Costs:
Steel plates from junkyard incl cutting, drilling, stut bolts, u chanel, welding, rental jack: ~ USD 800
Need retubing now since many damaged tubes can be seen. Corrosion might be the reason due to chem reaction of solvent. Acidity might have not been considered correctly in the design of the heat exchangers. Need to send samples to metallurgic lab to confirm.
Video: https://files.engineering.com/getfile.aspx?folder=...
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
Good job and thanks for sharing your progress and video.
Bagus,bagus.
Pierre
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
Don1980. Unfortunately we do not have such facilities here in Batam and it requires a high temperature I am sure.
RE: Extracting bundle of floating head heat exchanger
Thank you for sharing your field experience and detailed reasoning in solving this challenging HX problem.
Your extra effort by completion of this thread certainly helps us all ..
Thanks again
MJCronin
MJCronin
Sr. Process Engineer
RE: Extracting bundle of floating head heat exchanger
Horacio
https://www.linkedin.com/company/lagotuy/
RE: Extracting bundle of floating head heat exchanger
Another unit will be inspected the next 3 days with Eddy Current to check the wall thickness. Unfortunately we do not have any test rings for hydro test. I definitely would always buy optional test rings if you have corrosive or critical fluids that can cause tube damages. It looks like my assumption of mechanical failure might be wrong and we really created a corrosive environment inside due to operation conditions.
RE: Extracting bundle of floating head heat exchanger
Can you roll it Around 160 degree.?
https://mwi.solutions/technologies/wms-wcs-and-oms...
RE: Extracting bundle of floating head heat exchanger
Guys out there, I now need your input. My maintenance managed to damage 2 expansion bellows which are installed between floating outlet and end cap. Pic attached...
Right pic shows 6" bellow which is bent as they removed endcap without realizing there is a bellow. Now I need to straighten the bellow to be able to install it again.
Left pic shows 8" bellow (different heat exchanger) which was deformed (now 30 mm longer) during a hydro test. They did not restrict the bellow movement. So I need to get it back to original length.
Bellows are SS316 , the 6" bellow is made of 2 ply 0.6mm = 1.2 mm
8" is made 3 x 0.6 = 1.8mm
Buying new ones is not an option right now as it will take min 8 weeks
I am planning to heat the bellow with gas torch and carefully try to adjust them and replace within the next 3 months with new ones
Any comments? Thanks guys out there.
RE: Extracting bundle of floating head heat exchanger
RE: Extracting bundle of floating head heat exchanger
We have considered all these option but due to our product itself and the available space it looks like regularly cleaning is the only way. Larger units with spare heating surface might be an option to prolong the operation time but will be still a major modification.