Caustic embrittlement, Chemistry

Assignment Help:

Caustic Embrittlement: Caustic embrittlement is a type of boiler corrosion caused by using highly alkaline water in the boiler. During softening process by lime-soda processes, free Na2CO3 is usually present in small proportion in the softening of water. In high pressure boilers, Na2CO3 decomposes to give sodium hydroxide and carbon-dioxide.

  Na2CO3 + H2O = 2NaOH + CO2

And this makes boiler water "Caustic". The NaOH containing water flows into the minute hair cracks, always present in the inner side of boiler, by capillary action. Here water evaporated and the dissolved caustic soda concentration increases progressively. This caustic soda attacks the surrounding area, thereby dissolving iron of boiler as sodium ferrate. This causes embrittlement of boiler parts, causing even failure of the boiler. Caustic cracking can be explained by considering the following concentration cell. The iron surrounded by the dilute NaOH becomes the cathodes sides, which the iron in contact with concentrated NaOH becomes anodic part, which is consequently dissolved or corroded.

 

 


Related Discussions:- Caustic embrittlement

Ionic and covalent bonds, Ionic and covalent bonds are present in: (1) ...

Ionic and covalent bonds are present in: (1)  CCl 4                                               (2)  CaCl 2              (3)  NH 4 Cl

Acid halides, what are the properties of acid halides

what are the properties of acid halides

Electrode potentials, In an electrochemical cell a redox reaction perform...

In an electrochemical cell a redox reaction perform in two halves. Electrons are liberated by the oxidation half reaction at one electrode and go through an electrical circuit

Conductions, Factor of affecting conductions

Factor of affecting conductions

Rate of advancement, how do i calculate the rate of advancement of a week e...

how do i calculate the rate of advancement of a week electrolyte

The following has zero valency, The following has zero valency : (1) Sod...

The following has zero valency : (1) Sodium (2) Beryllium (3) Aluminium (4) Krypton Ans: Krypton

Ventilation can be improved , i. Talk about the terms "short circuiting" an...

i. Talk about the terms "short circuiting" and "turbulence" in settling tanks under the following headings - causes, effects and design improvements/remedial calculates taken to av

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd