terça-feira, 11 de março de 2014


Sulfuric acid is an inorganic chemical compound whose formula is H2SO4. It is a colorless, viscous oxidant, non-volatile liquid, your boiling point is 338 ° C and density 1.84 g/cm3. It is extremely soluble in water, but this must be done very cautiously, always pouring the acid in the water and not the reverse, because if it is not followed, vapors are released aggressively, causing severe burns to the operator's body or someone close.

  It is a corrosive and toxic acid, which can cause enough irritation and burns, and is harmful if there is inhalation, skin contact or ingestion.

  With the advent of the Industrial Revolution (from the eighteenth century to the present), which was originated in England, certain chemicals have become of commercial interest, necessary on a large scale. The sulfuric acid was one of the first of these "industrial products". It has even been said that measures the degree of industrialization of a country by the amount of sulfuric acid produced by its industrial park. Thus, the British Industrial invested large amounts of money, time and effort to the task of improving the process of production of sulfuric acid. Small gains in production led to huge profits due to the large amount consumed by industries.

  The process of producing sulfuric acid employed since 1749 was known as "the House Method Lead". In this technique, there was little understanding of the process, which basically requires air, water, sulfur, nitrate dioxide and a large container of lead. Of these ingredients, the nitrate was more expensive. This is because in the final stage of the process, nitrate (in the form of nitric oxide) was lost to the atmosphere, necessitating replacement of a stream of pure nitrate. This additional nitrate, in the form of sodium nitrate, had to be imported from Chile, making it very expensive.

  In 1859, John Glover helped in solving this problem by introducing a mass transfer tower to recover some of the lost nitrate. In this tower, the sulfuric acid (still containing nitrate) was dripped downwards against a stream of ascending gas. The ascending part of the absorbing gas nitric oxide. After the tower, the gas flowed back to the lead chamber where nitric acid was reused.

   The Tower Glover represented a trend in many chemical industries during the late nineteenth century. Economic pressures were forcing rapid development and modernization of chemical plants. A well designed plan, with new chemical operations, such as the Glover tower, representing the difference between success and failure in a highly competitive field of chemical industries.

  It is currently used in the contact process to produce sulfuric acid, which comprises the following steps:

Step 1 - Burns sulfur (S) in air (O2) to produce sulfur dioxide (SO2):
S (O) → SO2 + O2 (g)

Step 2 - Excess heat of combustion of sulfur is used to produce the steam needed to own fusion of sulfur and other uses of steam in the factory. Subsequently, the produced sulfur dioxide is oxidized to sulfur trioxide (sulfuric anhydride) in the presence of vanadium pentoxide (V2O5) as a catalyst:     2 SO2 (g) + 2 O2 → SO3

Step 3 - Finally, sulfur trioxide produced undergoes absorption with water (H2O) or a solution of sulfuric acid with the formation of concentrated sulfuric acid at 98 ~ 99%: 
SO3 (g) + H2O (l) → H2SO4 (l)

  This chemical has a huge importance in basic industry, the most widely used compound, behind only water. Some of its main uses are:

• Batteries of this lead-acid automotive contain sulfuric acid as the electrolyte;
• In the manufacture of explosives;
• In petroleum refining, removing impurities from gasoline and other oils;
• The production of other acids such as phosphoric acid (H3PO4) and nitric acid (HNO3);
• In the fertilizer industry.


COMSTOCK, M. Joan. History of Chemical Engineering. USA: American Chemical Society, 1980.

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