The client had a long history of pyrophoric activity when fractionation column overhead heat exchangers were pulled for maintenance. The exchangers produced smoke and heat when exposed to oxygen and would ignite in flames if not properly cleaned prior to pulling. This was especially dangerous considering the high elevation of the exchangers. Several inefficient methods of remediating the pyrophoric activity were attempted. They included trying to keep the bundles wet with a fire hose during the extraction process and filling the entire overhead system from the accumulator to the tower with a liquid oxidizing agent. Both methods proved to be ineffective, time consuming, and generated a significant amount of wastewater to process.
The client contacted RTI for assistance in solving the pyrophoric problem on the overhead exchangers. RTI recommend cleaning the fractionation column and entire overhead system with the patented Vaporganic® QuikTurn® process, followed by a vapor phase treatment of the overhead system with the patented Quench pyrophoric treatment technology.
Effectively dealing with pyrophoric issues requires the complete removal of all hydrocarbons from equipment. Removing the hydrocarbons exposes pyrophoric iron sulfide sites and takes away fuel for burning. RTI cleaned the fractionator and overhead system with the patented QuikTurn process to remove all hydrocarbons. Once hydrocarbon free, the overhead system was treated with steam and Quench to oxidize pyrophoric iron sulfide into iron oxide. Once oxidized with Quench, the pyrophoric iron sulfide no longer reacts with oxygen and produces heat. Thus, pyrophoric activity is prevented. The following overview shows the cleaning flow path and treatment with Quench.
Quench contains a field test marker that is easily detectable on the Quench test strip. When the reaction between Quench and iron sulfide is complete, the field test strip turns from red to blue. Quench is continuously injected into process equipment until there has been an over treatment of the iron sulfide, as indicated by a positive blue test strip. The positive blue test strip verifies that Quench has reacted with all iron sulfide and the reaction is complete.
Upon completion of the QuikTurn cleaning process and vapor phase treatment with Quench, the client was able to pull the overhead exchangers with no pyrophoric activity. The effective cleaning and vapor phase oxidation processes prevented the bundles from igniting in flames or self heating. The successful application created a much safer working environment during the turnaround.
Quench is an effective way to treat pyrophorics in overhead systems. It can also be used to treat main columns, horizontal drums, and other equipment that contains pyrophoric iron sulfide. Contact RTI to learn more about our patented process.