Steam Surface condenser 2

[deepu78]

thread391-504505
The response from a specialist steam surface condenser vendor with regards to tender (RFP) for design &fabrication of Steam Surface Condenser
1"We will not provide thermal & mechanical calculations.These are proprietary documents and we do not submit to client." Is this correct?
2."Carbon steel tubes are not used in vacuum shell side service." But SA 214 tubes are mentioned in HEI standards.Is there any issues with using SA214 CS tubes for SSC?
Thanks,
DV

 

[MJCronin]

My two cents worth:

1) We will not provide thermal & mechanical calculations.These are proprietary documents and we do not submit to client." Is this correct ?

What does your purchase contract say ? ... I have specified several of these and ALWAYS received thermal and ASME mechanical calculations. Competent vendors have been providing these for DECADES !! These calculations must be done to complete the design and cost the SSC vendor virtually nothing ... Does the vendor view these as an opportunity to "shake down" the purchaser for more money ?... Who is this SSC vendor ?... Identify him so the world can avoid him

[i]2) Carbon steel tubes are not used in vacuum shell side service.[/i]

Complete and utter BS ... On what basis is this statement made ? ... Is this another attempt at "shake down" to get more money ? .... Ask him to explain and provide refernces.... (In all fairness, most SSC have a nasty water on the tubeside and frequently use SS or other corrosion resistant material.... Stainless, Brasses, titanium and more exotic materials have all been used on SSCs)

Keep us posted and provide more details of the SSC that you wish to install .... We may be of great help to you !!!

Can you share details of your requirements ?

Where, in the world will this unit be installed ?

MJCronin
Sr. Process Engineer

 

[EdStainless]

You don't say what the application is, but in many cases I have seen customers not care about the calculations.
After all their contract contains performance criteria that impact the payment.
and they end up modeling the condenser themselves for internal use (performance tracking).
CS tubes are used, but ...
You have to be able to tolerate the Fe pickup in the condensate and your cooling water must be treated to be suitable.
In smaller process condensers it is not uncommon to use CS tubes.
In large main steam condensers it is never done.

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P.E. Metallurgy, consulting work welcomed

 

[deepu78]

Application: SSC for Turbine in nitric acid plant.
The current SSC tube material SA214(789 off BWG16 ,L=5.8 m long),changing to duplex will need a bigger size SSC. Due to space restrictions it is not possible.
Condenser normal duty (shell)Opr pr.76 mm Hg Abs.
Tube side normal duty opr pr :400kPag
Design Pr Shell side Kpag 100&Full Vacuum
Design Pr Tube side kPAg 517
Design Temp (Shell side& Tube side )105 Deg C
Edstainless : In large main steam condensers it is never done.Why?Any limitation in ASME Sec 2 specified?
Performace criteria-We specify that Thermal performance guarantee,How this can be enforced? Is there a time for evaluating performance?Maximum liability is limited to cost of HX for a fabricator.
MJCronin (Mechanical):ALWAYS received thermal and ASME mechanical calculations-What about HEI-2629 Thermal & Mechanical calculations? Have u received it?
DV

 

[davefitz]

edstainless is correct . The corrosion on the outside of the tube acts as fouling and the inside corrosion spalls off and the resulting water quality is not adequate for use in a high pressure boiler that feeds a steam turbine. Modern surface condensers use stainless , titanium, ferritic sea-cure, copper alloys, etc. Each material selection affects the type of water treatment used and also the spacing of the anti-vibration supports within the condenser.


"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[EdStainless]

Thanks Dave, yes, boiler/turbine water quality issues.
How much thinner was the duplex design? Half of the CS wall?
If it isn't a lot thinner go back and take another look.
We used to swap thin SS for thick brass tube all of time with no penalty.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed