Storage, Handling, and Properties of Sulfur, Sulfuric Acid, Oleum, and Liquid SO3
Storage, handling and safety
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12.1
Sulfur
12.1.1
Properties of Sulfur
Molecular weight Chemical symbol Appearance Solid Available commercially as coarse/fine mixture of broken lumps or as granules (as produced after recovering from petroleum refineries) Solubility in water Melting points for the different forms are: Rhombic Monoclinic Boiling point Flash point for pure sulfur Ignition point in the atmosphere
Specific heat capacity Rhombic sulfur Monoclinic sulfur
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32.0 S Rhombic or monoclinic crystals/fine yellow flakes
Insoluble 112.8 °C 119.0 °C 444.6 °C 188 °C 250 °C. This can come down to 170 °C due to the presence of hydrocarbon impurities 3.63 + 0.0064T K (range of temp. 273—368 K) 4.38 + 0.0044T K (range of temp. 368–392 K) (continued)
N.G. Ashar and K.R. Golwalkar, A Practical Guide to the Manufacture of Sulfuric Acid, Oleums, and Sulfonating Agents, DOI 10.1007/978-3-319-02042-6_12, © Springer International Publishing Switzerland 2013
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Storage, Handling, and Properties of Sulfur, Sulfuric Acid, Oleum, and Liquid SO3
(continued) Heat of fusion of sulfur Heat of combustion for the reaction S + O2−− → SO2 Ignition temperature for liquid sulfur Dust cloud auto ignition temperature Specific gravity Solid Rhombic Monoclinic
9.378 kcal/kg (−)70,900 kcal/kg mol Approx. 250 °C Approx. 190 °C
2.07 1.96
12.1.1.1 Storage, Handling, and Safety A large number of sulfuric acid and oleum plants use elemental sulfur as the main raw material. Liquid sulfur is taken out from the mines and is solidified. It is then made available as solid lumps or powder. Sulfur is also supplied as granules when recovered as elemental sulfur from petroleum refineries (by partial oxidation of H2S). It is transported by ships, railway wagons, or road trucks when solid. It is packed in bags of 500 kg or bigger capacity for ease of unloading at point of use and is dumped on grids of the melter (which are equipped with steam coils) either through small hand carts or by bucket loaders. Care should be taken to avoid dust clouds during handling due to the possibility of fires or explosions. Metallic parts of conveyors and bucket elevators should generally be electrically bonded together and earthed to avoid build-up of static electricity. Loaders and hand shovels should be of non-sparking materials. 12.1.1.2 Non-compatible Materials Sulfur should not be stored with along with chlorates, nitrates, or other oxidizing materials, mineral acids, or metal powders. No naked flames should be present in the sulfur storage area and all electrical wiring and motors should be flame proof. Hot permits should be issued by competent and experienced persons before undertaking any cutting or welding activities in such areas. Solid Sulfur Solid sulfur can be stored in open yards but it is better stored in covered sheds and protected from rain to avoid formation of acid. Rain water in the sulfur powder can increase steam consumption in the melter. Solid elemental sulfur is non-toxic. However, persons working at the melters can inhale sulfur dust or vapor present and th
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