Untitled Deck Flashcards
(24 cards)
What is sulfuric acid?
Sulfuric acid (H₂SO₄) is an essential inorganic acid in the chemical industries.
What is the global production of sulfuric acid?
The global production is 180 million tons per year.
What are the applications of sulfuric acid?
Applications include fertilizers (superphosphates), petroleum refining, detergent manufacturing, dyes, plastics, explosives, and metal treatment.
What is the molar mass of sulfuric acid?
The molar mass is 98.08 g/mol.
What is the boiling point of sulfuric acid?
The boiling point is 337°C.
What is the melting point of sulfuric acid?
The melting point is 10.31°C.
What is the density of sulfuric acid (98%)?
The density is 1.836 g/cm³.
What are the key steps in the contact process for sulfuric acid production?
The key steps are combustion, oxidation, and absorption.
What occurs during the combustion step in the contact process?
Sulfur is transformed into sulfur dioxide (SO₂) at a temperature of 900–1100°C.
What is produced during the oxidation step in the contact process?
Sulfur dioxide (SO₂) is converted into sulfur trioxide (SO₃) with a maximum conversion rate of 98% at an optimal temperature of 430°C.
What happens during the absorption step in the contact process?
Sulfur trioxide (SO₃) reacts with water (H₂O) to form sulfuric acid (H₂SO₄).
What is the purity of the sulfuric acid obtained from the absorption step?
The sulfuric acid obtained is 98% pure and is diluted to reach commercial concentrations.
What are the two variants of the contact process?
The two variants are simple absorption and double absorption.
What are the characteristics of the simple absorption variant?
It has a yield of 98% and high SO₂ emissions (1900 ppm) with lower installation costs.
What are the characteristics of the double absorption variant?
It has a yield of 99.6%, reduced SO₂ emissions (350 ppm), and higher costs, complying with modern standards.
What are the main raw materials for sulfuric acid production?
The main sources are elemental sulfur (85% of global production), metal sulfides (pyrite, blende, galena), and H₂S extracted from natural gas by the Claus process.
What are the exothermic reactions involved in sulfuric acid production?
The combustion of sulfur releases -3026 kJ/kg, the conversion of SO₂ to SO₃ releases -1004 kJ/kg, and the absorption of SO₃ to form H₂SO₄ releases -1390 kJ/kg.
What is the total energy released during sulfuric acid production?
The total energy released is 5671 kJ/kg of H₂SO₄.
How is energy recovered in sulfuric acid production?
Energy is recovered in the form of superheated steam, which is used to power turbines and pumps.
What environmental problems are associated with sulfuric acid production?
Problems include SO₂ emissions, which are toxic and polluting, and the formation of sulfuric mists.
What solutions are proposed to mitigate environmental issues in sulfuric acid production?
Solutions include switching to the double absorption process and treating tail gases with lime, soda, or ammonia.
What is a simplified diagram of the contact process?
- Sulfur (S) + O₂ → SO₂ (Combustion)
- SO₂ + ½ O₂ → SO₃ (Catalysis - V₂O₅)
- SO₃ + H₂O → H₂SO₄ (Absorption)
What are the advantages and disadvantages of simple absorption?
Advantages: low installation cost. Disadvantages: low yield and high emissions.
What are the advantages and disadvantages of double absorption?
Advantages: high yield and less pollution. Disadvantages: higher cost and complexity.
