Marine Vapour Control Systems
by Melissa Lenhart, Ken Wright, and Chuck Baukal John Zink Co. LLC.
Two common methods for controlling the emission of vapours from product storage and transfer operations include vapour recovery units (VRUs) and vapour combustion units (VCUs).
The transfer of volatile organic liquids such as gasoline, higher vapour pressure hydrocarbon chemicals, and ethanol into transport vessels such as trucks, railcars and ships generate hazardous vapours, which if left uncontrolled result in adverse effects to the environment. Control of volatile organic compounds (VOCs) from railcar, trucks, and storage vessel operations has been required by a majority of regulatory agencies around the world for many years. Now many of these same agencies are requiring control of VOC containing vapours from marine vessel loading, i.e. barges and ships.
Collecting and controlling vapour from marine operations presents new challenges for the industry that typically result in additional safety requirements compared to land-based systems. In the United States, vapour control from marine loading operations has been practiced for over 15 years, and regulations for safety equipment in the vapour collection system have been published by the United States Coast Guard (USCG). Although these regulations are not enforced outside of the US, they do provide a proven guideline for safety, and have set a precedent in the design of vapour control systems worldwide. This article will briefly discuss some of the history of the added safety requirements and then will present the equipment used in these marine vapour control applications.
