Draining of heat exhanger 2

[sider]

In one of the CHW projects, I had to deal with a cooling unit heat exchanger whose IN/OUT connections were located in the middle of its overall height. After the hydro test, the heat exchanger could not be drained properly, as shown in the picture, as the lower part of it would be flooded since the drain is not located at the lowest point.

Problem

Exchanger Type

Does anybody have any idea how this could be done?

 

[Latexman]

Blow it out with hot air or nitrogen until dry.

Good Luck,
Latexman

 

[sider]

Blow it out with hot air or nitrogen until dry.

Is there a way to know how much static pressure would I require in order to push the air through the water?
Do you usually heat up nitrogen before being introduced into the system?

Another idea would be to vacuum and boil out the remaining water, however, I am not sure what kind of vacuum pump could handle such an amount of water (4 liters), and not sure if should I be afraid of freezing the water out due to the cooling during boiling without heating the whole HE (since the copper piping of HE has a small diameter, maybe ice formation could increase the volume and break the pipe).

 

[Latexman]

What is CHW?

Good Luck,
Latexman

 

[sider]

Sorry for the abbreviation...CHW is chilled water

 

[LittleInch]

Your diagram isn't correct and then the photo, presumably a typical, doesn't match either.

Can you correct the diagram so that we can actually see the flow path. Is there a vent anywhere?

It's a strange design if the designer didn't think about this or are you mounting it not as intended?

You're not giving us accurate information here I think.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Latexman]

Why do you want to remove hydrotest water before running chilled water through it?

Good Luck,
Latexman

 

[sider]

Your diagram isn't correct and then the photo, presumably a typical, doesn't match either.

Can you correct the diagram so that we can actually see the flow path. Is there a vent anywhere?

It's a strange design if the designer didn't think about this or are you mounting it not as intended?

You're not giving us accurate information here I think.

Here is the real illustration

Unfortunately, I don't have the schematic for flow path inside heat exchanger, just for connection points.

Why do you want to remove hydrotest water before running chilled water through it?

We are hydro testing the unit, and after that, it is shipped to the site, however, during transport and storage the remaining water could be frozen (we cannot control conditions during this period). Usually adding glycol resolves this issue, however, I would like to not have water left, so the unit could be shipped in a dry state.

 

[Latexman]

How big is the assembly? Weight? Can it be positioned to drain better. I.e. laid at an angle so the tubes in the coil are horizontal with the drain valve below them? What is the MAWP of the coils?

Good Luck,
Latexman

 

[sider]

Unfortunately no, the unit is fastened to subtrack or floor, and it is usually packed between the other equipment(standing cabinets)

 

[Latexman]

What is the MAWP of the coils? What is the air pressure in your factory?

Good Luck,
Latexman

 

[sider]

What is the MAWP of the coils? What is the air pressure in your factory?

The unit is rated for 16 bar (tested with water). Unfortunately, I am not aware of the air pressure in the factory...I think compressed air is available, but not sure if could be used as such since the distances for compression stationary lines are far away from the assembly grounds. Could a blower with a heater be sufficient (3000 Pa of static pressure)?

 

[LittleInch]

It implies that this HX is being mounted 90 degrees out of the orientation it was intended for, i. with inlet and outlet on the bottom maybe?

All a bit odd. Are you sure there isn't a drain plug somewhere?

What does the piping look like on the other side?

Any vendor drawings?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Latexman]

[Δ]P = 0.03 bar? I suspect it will take forever and/or not do a good job.

There are vendors/contractors that have the right equipment and experience to do this. I recommend you Google for them locally or talk to your maintenance or purchasing.

Good Luck,
Latexman

 

[TugboatEng]

It's a refrigeration system. Someone must have a vacuum pump near by.

 

[sider]

ΔP = 0.03 bar? I suspect it will take forever and/or not do a good job.

There are vendors/contractors that have the right equipment and experience to do this. I recommend you Google for them locally or talk to your maintenance or purchasing.

Could you point out what kind of technology I would look for? Compressed hot dry air? High-temperature nitrogen purge?

It's a refrigeration system. Someone must have a vacuum pump near by.

Is it possible to remove such quantities of water by vacuum? I believe oil sealed vacuum pump wouldn't be any good since the oil would mix with water, and frequent changes of oil should be made.

 

[shvet]

... what kind of technology I would look for? Compressed hot dry air? High-temperature nitrogen purge?

Any gas with temperature well above dew point.

Is it possible to remove such quantities of water by vacuum?

Yes, it is.
You should put HE under vacuum below water vapor pressure @ ambient temperature. For example if ambient temperature is 20°C vacuum should be bellow 2 mbara.
You can warm HE up to let's say 70°C if you have no proper vacuum source or >100°C of you have no that at all. Make sure that you will not overheat HE above design temperature.

For info - vacuum swing is one of methods to measure dryness of process equipment e.g. long-distance pipelines

 

[sider]

Yes, it is.
You should put HE under vacuum below water vapor pressure @ ambient temperature. For example if ambient temperature is 20°C vacuum should be bellow 2 mbara.
You can warm HE up to let's say 70°C if you have no proper vacuum source or >100°C of you have no that at all. Be sure that you will not exceed HE design temperature.

What vacuum technology/pump could be the best fit for such an operation? Should I be worried about freezing of water inside since it looses energy(temperature is going down)?
There is no possibility to heat HE, maybe just have some hot air blower around and have temperature around HE at approximately 35°C.

 

[shvet]

What vacuum technology/pump could be the best fit for such an operation?

Site specific

Should I be worried about freezing of water inside since it looses energy(temperature is going down)?

Yes, you should

There is no possibility to heat HE

Sounds doubtful

If you are worried about time schedule then you can siphon most part of water by a flexible hose.

https://www.amazon.in/Clear-Tubing-Plastic-Flexible-Beverage/dp/B07W7HTBBS

 

[sider]

It implies that this HX is being mounted 90 degrees out of the orientation it was intended for, i. with inlet and outlet on the bottom maybe?

All a bit odd. Are you sure there isn't a drain plug somewhere?

What does the piping look like on the other side?

Any vendor drawings?

The current orientation is right, since the HE is an integral part of the cooling unit, and the unit is basically a cabinet, there is no possibility of the wrong installation, it is just how it is.
There is no piping on the other side, and there is no drain for sure...also the lower part of the HE could not be reached, because the fan module is in front of it...it is possible to reach it only if a few things are disassembled, which is not really the direction I would like to go.

Sounds doubtful

Unfortunately, the HE cant be reached (in front are filters, fan module, electrical connections, etc) which have to be disassembled (lot of resources necessary).

If you are worried about time schedule then you can siphone most part of water by a flexible hose.

https://www.amazon.in/Clear-Tubing-Plastic-Flexibl...

Could you elaborate please, sot sure do I get this right