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

Chemical shift, factors influencing chemical shift

factors influencing chemical shift

Microwave digestion, if insoluble residues are found after the microwave di...

if insoluble residues are found after the microwave digestion with nitric acid, how to improve?

Explain heavy water, Explain heavy water? Ans) Isotopes of H 2 O, D 2 ...

Explain heavy water? Ans) Isotopes of H 2 O, D 2 O

Given free energy, Br2(g)=2Br(g) dG=161.69KJ/mol at 298.15K Find kc and kp....

Br2(g)=2Br(g) dG=161.69KJ/mol at 298.15K Find kc and kp.

What is compound, Q. What is compound? A compound is a substance whic...

Q. What is compound? A compound is a substance which consists of two or more elements chemically combined. The elements in a compound aren't simply mingled together as they a

Oxidation - reduction reactions, Iodine is used as an antiseptic treatment,...

Iodine is used as an antiseptic treatment, but it can be poisonous if taken internally! Be sure that the solution is handled with care, and avoid all direct contact with the soluti

What does thermodynamics helps in predicting, Predicting the feasibility of...

Predicting the feasibility of reaction and does not show the rate of chemical reaction

Types of elimination reactions, Types of Elimination reactions Eliminat...

Types of Elimination reactions Elimination reactions are divided into two general categories, (A) α - elimination reactions or 1, 1-elimination reactions. (B) β - elimin

The number of neutron in tritium is, The number of neutron in tritium is : ...

The number of neutron in tritium is : (1) 1        (2) 2        (4) 3        (4) 0 Ans: 2

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