Chemical Decontamination of a Sulfur Recovery Unit Sour Water Tank

Results Achieved

Complete elimination of hydrogen sulfide and reduction of ammonia to acceptable levels

Over 80% reduction in outage time

No personnel exposure to hazardous materials

No additional disposal expense

Chemical profiles


Designed for instantaneous and permanent elimination of Hydrogen Sulfide present in refining and other process equipment.

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FQE Ammonia Odor

Exceptionally rapid removal of potentially toxic and harmful ammonia odors in refinery operations.

A large petroleum refinery in New Jersey used our hydrogen sulfide abatement product, FQE™ H2S, and ammonia control product FQE™ Ammonia Odor to decontaminate a sour water tank in their sulfur recovery unit (SRU) containing 1,438 m3 (380,000 gallons) of sour water.


The initial H2S readings from the sour water vessel exceeded 80,000 ppm (8.0%). A 20% FQE H2S mixture in water was prepared and pumped into the tank. The tank contents were circulated for 48 hours to ensure good contact was made between the vessel water and FQE H2S. The tank contents were sampled every two hours with the H2S being reported at 0 ppm after 32 hours. Prior to the hydrogen sulfide treatment, the vessel was treated with FQE Ammonia Odor for ammonia control. The required amount of FQE Ammonia Odor was pumped into the tank and the vessel contents were circulated for 12 hours until the ammonia level was below the acceptable 10 ppm.


The chemical circulation was performed at an ambient temperature and was applied from bottom to top through a 3D nozzle mounted through the vessel’s top manway access. The spray nozzle was used to eliminate the high H2S and ammonia concentrations present in the vessel’s head space. Upon completion, the treated water was processed through the wastewater treatment plant without delays.


Typically, this process is conducted by the slow addition of a strong oxidizing liquid over a 7-10 day period of time, resulting in extra time and additional disposal considerations being required.

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