THE CHEMICAL ENGINEERS' RESOURCE PAGE
EMAIL ARCHIVE MESSAGE 007

I would like to know how sulfuric acid is produced on an industrial scale including reactants and reaction conditions.

First, elemental sulfur is burned is a furnace to form sulfur dioxide:
S + O₂ ---> SO₂
The sulfur dioxide is reacted with oxygen over a vanadium catalyst:
SO₂ + 1/2 O₂ ---> SO₃
Typical feeds for the reactor that converts sulfur dioxide to sulfur trioxide are 11% SO₂, 16% O₂, and 79% N₂.  The nitrogen does not participate in the reaction  (inert).  A 1000 ton/day plant would have a reactor with an area of about 200 ft².  Typical reaction temperatures are between 800 ⁰F and 1100 ⁰F depending on many factors.  Once the sulfur trioxide is formed, it is bubbled through water where the final reaction takes place:
SO₃ + H₂O ---> H₂SO₄

A process flow diagram (PFD) for this process appears in a book entitled Elements of Chemical Reaction Engineering, 2nd Edition, p 435, by H. Scott Fogler.  Published by Prentice Hall, copyright 1992, ISBN 0132635348