Carlos Flores is the Plant Manager at Infra, SA in Tlalnepantla, Mexico. Infra manufactures Ethylene Oxide gas. Ethylene Oxide gas (EtO) is used to reduce or render inactive microbial populations in sterilization processes where traditional methods involving heat, moisture or radiation are inappropriate.

The venting of EtO to the atmosphere however is prohibited and Infra consulted the engineers at its supplier, Air Products and Chemicals, Inc., for assistance. Air Products turned to Croll Reynolds and the two companies worked together to arrive at a solution for Infra.

Croll Reynolds’ proprietary EtO scrubbing systems utilize absorption and hydrolysis of oxides to glycols to effectively treat EtO contaminated gases. The conversion of EtO to ethylene glycol involves first breaking the EtO bond to release oxygen and ethylene radicals before the ethylene radicals in turn form ethylene glycol. Because mass transfer and hydrolization factors are critical in this two-part reaction, the system must be designed to ensure adequate dwell time. The conversion reaction is hastened by introducing an acid catalyst.

Croll Reynolds engineers designed two packed towers in series, each five feet long and eight inches in diameter, together with a reactor and solution tank combined in a single 4,300 gallon vessel, 8 feet in diameter by 13.5 feet high. An internal baffle separates the two components of the tank. Other system components include a pump and a heat exchanger for cooling the ambient recirculating liquid during the hot Mexican summers.

The system is designed to operate continuously at a removal efficiency of 99%+. Plant manager Flores reports that the Croll Reynolds system has operated exactly as specified for the past three years.