×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Caustic plus HCl---What happens?
2

Caustic plus HCl---What happens?

Caustic plus HCl---What happens?

(OP)
Dear all,

       I was trying to figured out from my mind as to what will be the effect of combining HCl and NaOH.
       This was after one of our an auditor for our plant said that NaOH and HCl tanks should have separate drainage as when they combine "they could produce explosion".
       Can any of you guys clear my mind? Im supposed that when acid and caustic is combined, a neutral pH arises (when same in qty).


gladkenn

RE: Caustic plus HCl---What happens?

You forgot about the enormous release of heat...

RE: Caustic plus HCl---What happens?

gladkenn,

Heat of Neutralisation of HCl and NaOH is approx -57.1 kJ/gmol.  

Lets say you have equal quatities of HCl and NaOH and have 10m3 of 48% NaOH at 40degreesC and stoichiometric equivalent of HCl then you have 14,922 kg NaOH solution which contains 7,162.6kg NaOH = 179,064gmol.  

Therefore the energy from reaction is 10,224.6 MJ of heat, using 4.087 kJ/kg specific heat (as a roughy) with a start temp of 40degreeC then final temp roughly would be about 150degreeC.

As such you can see why you use seperate drain lines for the tanks as this energy will release suddenly if they mix quickly as opposed to a nice slow rise in temp.

Cheers.

RE: Caustic plus HCl---What happens?

Of course, you might also want to consider if you have adequate safeguards on tanker-unloading.
Is it possible, one cold Monday morning or rainy Friday night, that the tanker driver could couple up to the wrong tank inlet system?
I am doing some work for a company that is concerned about what might happen if the tanker delivers concentrated caustic into the nitric storage by mistake.
They are concerned enough to want to fit a variety of different sensors in the tanker unloading system so that they can "identify" the product and react if it isn't the product they expect i.e. make enough measurements to provide a high level of confidence that they have the right product going to the right tank.

JMW
www.ViscoAnalyser.com

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources