Challenge

A client required the stripping and cleaning of a butane storage vessel as part of a facility transition to renewable diesel service. Envent was assigned the responsibility of degassing the tank and delivering continuous vapor control to minimize tank atmosphere to non-explosive levels. Furthermore, the tank needed to be inerted to prevent oxygen ingress into the vapor space, and the sub-freezing ambient temperature conditions had to be taken into account while devising a solution.

 

Solution

Envent supplied two CSA-compliant EMECS 70 thermal oxidizers to offer redundant vapor control for the butane tank. Each oxidizer unit was modified in accordance with Canadian Standards, enabling their operation under local permitting. Both units were integrated into an existing flare line system, allowing tank vapors to be channeled to each combustor. In addition, Envent provided a nitrogen generation system to introduce inert makeup gas into the tank atmosphere. Each generator was capable of heating the nitrogen prior to injection, preventing the formation of condensable materials in the vapor lines. As a result, Envent continuously swept VOC-laden vapors to the thermal oxidizers for 99.9% DRE combustion, while oxygen-free inert gas was introduced into the tank volume.

 

Benefit

The thermal oxidizer system, furnished by Envent, enabled the client to successfully degas the butane tank to levels appropriate for manned entry and maintenance. Envent delivered a turnkey system that complied with all local regulations, resulting in a seamless entry and setup process. The end user was also able to minimize their emissions and adhere to their maintenance schedule.