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

Determine the density of salt, A tank contains 50 gal of a solution of NaCl...

A tank contains 50 gal of a solution of NaCl in water (20% wt). To wash the tank, we supply fresh water at 10 gal/min and drain the tank at the constant rate of 10 gal/min. Determi

Explain aldol condensation, Write one reaction each to exemplify the follow...

Write one reaction each to exemplify the following: (a) Aldol condensation (b) Friedel-Crafts reaction

Buffer.., Why is it important to know pka of a buffer

Why is it important to know pka of a buffer

Atoms and molecules, what are the application of law of chemical combinatio...

what are the application of law of chemical combination?

Draw the structures of white phosphorus and red phosphorus, Draw the struct...

Draw the structures of white phosphorus and red phosphorus. Which one of these two types of phosphorus is more reactive and why?

The solvent power of carbon dioxide, Calculate the pressures required to ac...

Calculate the pressures required to achieve a density of 220 g dm -3 , 330 g dm -3 , and 440 g dm -3 at temperatures of 305 K and 350 K.   Properties, like the solvent powe

Assignment, solution and collegative properties explanation

solution and collegative properties explanation

The nature of bonding in graphite, The nature of bonding in graphite is: ...

The nature of bonding in graphite is: (1) Covalent                                       (2) Ionic     (3) Metallic (4) Coordinate Ans: Covalent

Define why the glocose and fructose form the same osazone, Glucose and fruc...

Glucose and fructose are epimers so they are differ in their second carbon position and remaining is same so when they react with phenylhydrazeen they give same osazone

Differential extraction of organic acids, What would happened if I put sodi...

What would happened if I put sodium hydroxide instead of sodium bicarbonate into diethyl ether?

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