Page 11 - CCPS Golden Rules - Chloral Alkali

Golden Rules for Chlor-Alkali

Golden Rule #3: Do Not Allow Chlorine to Come into Contact with Organic Oils and Greases.

❖ Why:
Chlorine is a strong oxidizer. It reacts violently with most organic oils and greases and can result in a fire
or explosion especially at elevated temperatures [13] [18].
Chlorine reacting with organic oils and grease can quickly initiate chlorine/steel fires [13] [18].
Small quantities of organics such as grease on a gasket can result in fires, damaging piping, gaskets,
etc. resulting in chlorine releases [13] [18].
Explosions can result if larger amounts of organics come in contact with chlorine [13] [18].
New piping and equipment when not cleaned properly can contain cutting and fabrication oils/greases.
Incident History:
Approximately 750 pounds of chlorine escaped when the suction chiller vessel for a chlorine
compressor failed. The failure was caused by an iron-chlorine fire causing a hole in the vessel. The
vessel had just been repacked and the failure occurred during the start-up phase of the process.
Investigators determined that the pall ring packing was contaminated with mineral oil and moisture
on the pall ring packing. The probable cause of the incident was a chlorine/steel reaction. This
reaction was likely caused by elevated temperatures due to the presence of oil and water, which
initially reacted with chlorine [10].
During a plant start-up of a metals-chlorine facility, a reaction occurred in the purification tower
causing it to exceed its design pressure and blowing a rupture disc set for 85 psig. Within a few
seconds, the piping around the rupture disc failed, releasing chlorine to the atmosphere. Within a
few minutes, the insulation around the tower melted and caught on fire. The investigation team
concluded that heat was initially generated by a chlorine-water (hydrolysis) reaction. The rust
particles and oil still present in the tower packing helped to catalyze the chlorine and oil reaction,
which also generated heat. With sufficient amounts of water and oil reacting, a spot in the tower got
sufficiently hot to initiate the reaction between the chlorine and the packing [10].
❖ How — General:

All equipment and packing must be free of organic materials, oils, and greases before use in chlorine
service [8] [14] [18].
Equipment and components need to be properly cleaned, identified as cleaned, dried, and packaged
prior to chlorine service. A certificate of “cleaned for chlorine service” should be provided [8] [14] [18].

Updated January 2024 Page 8 of 28