Dissolved oxygen in water, Chemistry

Assignment Help:

Q. What do you understand by dissolved oxygen in water? How does it create trouble in boiler? Give chemical methods with suitable reactions to remove it from the water.

Ans.

Presence of dissolved oxygen: At room temperature about 8 ppm of dissolved oxygen is present in water. Oxygen enters the boiler through raw make up water. When water containing the free gas is evolved under prevailing high temperature of boiler and attacks the boiler material.

2Fe + 2H2O + O2 = 2Fe (OH) 2

4Fe (OH) 2 + O2 + 2H2O = 2[Fe2O3.2H2O]

Removal of dissolved oxygen:

1. Chemical means: Oxygen can be removed by adding calculated amounts of certain chemicals such as Na2SO3, Na2S and N2H4.

         Na2SO3 + O2 = 2Na2SO4

      Na2S + 2O2 = Na2SO4

However, the sodium sulphate so formed may decompose in high pressure to form H2SO4. Hydrazine (N2H4) is found to be an ideal compound for removing dissolved oxygen since the products are water and nitrogen gas

                                          N2H4 + O2 = N2 + 2H2o

Mechanical means: It works on Henry's law and Dalton's law. Solubility of gas is directly proportional to pressure. Mechanical desecrator is used 


Related Discussions:- Dissolved oxygen in water

Explain propene, Explain propene In propene, the H 3 C-C bond d...

Explain propene In propene, the H 3 C-C bond dipole adds vectorially to the smaller H-C bond dipole; the resultant is smaller than the H 3 C-C bond dipole itself, as th

S block elements.., lithium and beryllium markedly differ from other member...

lithium and beryllium markedly differ from other members of their respective groups.

Reaction involving cleavage of with removal of h as proton, Reaction involv...

Reaction involving cleavage of with removal of 'H' as proton Alcohols are stronger acids as compared to terminal acetylene but are not acidic enough to react along with aqueous

Reactivity, why HOH is not harmful to our body but Phenol is?

why HOH is not harmful to our body but Phenol is?

S block elements, lithium and beryllium markedly differ from other members ...

lithium and beryllium markedly differ from other members of their respstive groups

Determine electrons in carbon atom, The number of unpaired electrons in ca...

The number of unpaired electrons in carbon atom in excited state is: (1) One  (2) Two          (3) Three      (4) Four Ans: Four

Define the term - extrusion, Define the term - Extrusion It is a meta...

Define the term - Extrusion It is a metal working process that produces long lengths of uniform cross sectional area from a metal billet by causing the latter to flow under h

Find the equilibrium extent of reaction, The gas stream from a sulfur burne...

The gas stream from a sulfur burner is composed of 15-mol% SO 2 , 20-mol% O 2 , and 65-mol% N 2 .  This gas stream at 1 bar and 680°C enters a catalytic converter, where the SO 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