6 replies to this topic

[IonCube]

I am designing a sulphuric acid xchanger using Symmetry (previously VMGsim)

 

Now can anyone summarize from his/her experiences what mechanical parameters have the highest effect on A,B,C... flow ratios? I am mostly interested in Baffle cut & pitch & how can these x2 enhance B flow

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[Pilesar]

Exchanger design has lots of parameters that interact so you should not ignore any of them. A single bad parameter choice can doom the design. See the TEMA guidelines for mechanical constraints. Specialized exchanger design software tools are very useful.

[breizh]

Hi,

Because of the nature of your product (H2SO4 solution), I don't believe that CS will the right material. I would check for graphite and request a design from reputable companies familiar with this technology.

You may want to try with Mersen.

Good luck

Breizh 

[IonCube]

Hi,

Because of the nature of your product (H2SO4 solution), I don't believe that CS will the right material. I would check for graphite and request a design from reputable companies familiar with this technology.

 

Its close to 83% acid by weight so no worries I have checked ColePalmer material compatibility charts.

 

However using this reference: https://www.cheresou...cient/?p=113944

 

I have realised shell side film coefficients are limiting [shell side has acid]. If such is the case what physical changes should a designer incorporate?

Edited by IonCube, 27 June 2023 - 09:36 AM.

[shvet1]

 

Hi,

Because of the nature of your product (H2SO4 solution), I don't believe that CS will the right material. I would check for graphite and request a design from reputable companies familiar with this technology.

 

Its close to 83% acid by weight so no worries I have checked ColePalmer material compatibility charts.

 

 

Sounds bad.

 

Diluted H2SO4 is extremely corrosive. Cooling down below 25°C at any point of shell side is required to guarantee corrosion rate <0.5 mm/year. As per my experience with 85% H2SO4 CS and SS are not recommended because of corrosion rate much more than 1 mm/year. I have encountered glass-lining, PTFE-lining, lead-lining, alloys or even sometimes graphite for such environment.

 

You ignore velocities while velocity of H2SO4 is crucial as corrosion and velocity are interconnected. It looks like critical points of shell and internals will be damaged shortly after start. Hydrogen grooving is ignored too.

 

Note that after tube corrosion HE will become unsafe because of H2SO4 uncontrolled dilution- > overheating -> corrosion -> boiling -> overpressure.

 

I would not like to work on equipment such design. See NACE RP0391 and NACE SP0294 as an examples of a proper design but other kind of.

 

PS

 

Check freezing temperature of H2SO4 - it is 8°C. We often struggled with clogging of piping and equipment caused by inadvertent dilution an/or overcooling.

25°C minus 8°C minus a safety factors 5°C for both limits = 7°C - a rather narrow range for a proper operating range.

 

Note that corrosion rates of CS and SS in diluted H2SO4 are the same, there is no difference.

 

Note that hydrogen explosions was reported in such environment.

Attached Files

•  VEOLIA Sulphuric Acid.pdf   3.66MB   738 downloads

Edited by shvet1, 29 June 2023 - 12:11 AM.

[breizh]

Hi,

Data from a reputable company.

your design is at risk if you don't use the right material.

Breizh 

[horatorres]

Its close to 83% acid by weight so no worries I have checked ColePalmer material compatibility charts.

 

CS is not acceptable for 83 % of h2so4 concentration.. SS is not recommended.  but it depends on the temperature..

 

Be aware

 

Horacio