Acetylene Production from Calcium Carbide

The process under analysis comprises three major sections: (1) Acetylene generation; (2) Purification; and (3) Carbide Lime Recovery.

Acetylene generation. Initially, the calcium carbide is mixed with the water, which is present in large excess in the chamber (carbide-to-water principle) to help dissipate the heat of reaction between these two components generating the gaseous acetylene. A gaseous stream of acetylene and impurities, mainly sulfur and phosphorus compounds, exits from the generators top and proceeds to the purification section while a liquid stream of lime slurry exists from the bottom of the gasification tank as a by-product.

Purification. The acetylene formed first passes through a scrubbing tower, where the solids conveyed by the gas are removed. Subsequently, the Acetylene is fed to an absorption column where it flows countercurrent to a sulfuric acid solution, which acts as an oxidizing/neutralizing agent for the removal of impurities present in the Acetylene stream. The Acetylene is then passed through a caustic scrubber, where sulfur dioxide formed in the absorber column is removed by a caustic wash. Finally, the Acetylene is compressed, cooled and dried in silica gel beds before being sent directly to nearby facilities where it is consumed.

Carbide Lime Recovery. The carbide lime slurry coming from the Generator is fed to a decanter, in which a lime sludge is obtained and sent to a press filter to reduce the humidity to about 30%. The carbide lime cake is dried, crushed and sent to warehouses at the facility’s OSBL to be stored.