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Here, I have explained Unit Processes including Combustion, Oxidation, Causticization, Nitration, Isomerization in Chemical Engineering point of view.
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Unit Processes (Part-1) Topics Covered: 1. Combustion 2. Oxidation 3. Causticization 4. Nitration 5. Isomerization
Combustion Explanation ❑ Combustion is a high-temperature exothermic chemical reaction between a fuel and an oxidant, usually atmospheric oxygen. ❑ It produces gaseous mixture of product which is known as smoke. ❑ Complete combustion produces CO2and H2O, if CO is formed, then the reaction is known as partial combustion. ❑ It is spontaneous reaction. e.g. 2C8H18(l) + 25O2(g) → 16CO2(g) + 18H2O (g) (octane) Applications Fuel and Power Equipment Use For That Boilers (steel, Firebrick)
Oxidation Explanation (Discussion is limited to oxygen transfer) ❑ In terms of oxygen transfer, oxidation is defined as the chemical reaction in which a substance gains oxygen. e.g. 4Al (s) + 3O2(g) → 2Al2O3(s) (alumina) Equipment Use For That Applications Waste Water Treatment Tanks (Concrete) Water gas Generators (steel, brick) Industrial gases (CO2, H2) Boilers (steel, brick), Reactors (Alloy steel) Phosphoric acid from Phosphorus Oxidizers (Carbon, graphite) Sulphuric Acid Sulphur burners (steel), Converters (steel, cast iron), Chambers (lead lined) Nitric Acid from NH3 Oxidizers (steel) Paints and Pigments Reactors, kettles, mixers (steel) Linoleum Oxidizing rooms (brick) Perfumes Reactors (enamel, steel) Fermentation: Acetic, Critic and Gluconic acids Tanks (wood, stainless steel), Trays (aluminum) Phthalic Anhydride Reactors (steel) Formaldehyde Oxidizers (steel) with silver gauze catalyst Reactors and condensers (stainless steel) Acetic Acid from (CH3CHO) Reactors (stainless steel) Camphor
Causticization Explanation ❑ Causticization is a function in which sodium carbonate in green liquor reacts with calcium hydroxide from slaker to form sodium hydroxide and calcium carbonate. e.g. Na2CO3+ Ca(OH)2→ CaCO3+ 2NaOH Applications Caustic Soda Equipment Use For That Causticizers (steel)
Nitration Explanation ❑ In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. ❑ Organic compounds are nitrated by both ionic and free-radical reactions. Ionic nitration are employed extensively with aromatics, compounds containing hydroxyl groups and amines. Free-radical nitration is used for paraffins and cycloparaffins. ❑ Nitrating agents are: mixtures of HNO3and H2SO4, mixtures of N2O5and HNO3, mixtures of N2O4and H2SO4, HNO3and NO2. e.g. C6H6(l) + HNO3(l) → C6H5NO2(l) + H2O (benzene) (nitrobenzene) Applications Equipment Use For That Nitrators (cast iron and stainless steel) Nitrators and Separating Columns Nitrators (cast iron and stainless steel) Reactors (Copper) Intermediates for dyes, nitrobenzene etc. Nitro-paraffins Explosives Perfumes
Isomerization Explanation ❑ Isomerization is the process in which a molecule, ion or molecular fragment is transformed into an isomer with a different chemical structure isomerization. e.g. tautomerization. ❑ When the isomerization occurs intramolecularly it may be called as rearrangement reaction. ❑ Catalyst used for isomerization are Fridal-Craft catalyst, tungsten sulfide, bifunctional catalysts , zeolite containing catalyst with noble metals like Pt or Pd and complex catalysts. heat e.g. n-Butane Iso-Butane Applications Petroleum Industry Equipment Use For That Isomerizers (steel)