Rotork
Cut VOC losses from tanks by maintaining constant pressure
Minimizing emissions of volatile organic compounds (VOCs) from oil tankers in transit is challenging because of fluctuating ambient conditions experienced during sea voyages. Controlled release of VOCs is often undertaken when the gas pressure in the tank approaches a pre-set threshold. The Vocon Valve and Reporting System (photo) controls the vapor pressure inside oil cargo tanks to minimize and control VOC emissions. The system, which combines a venting control valve operated by an electric process valve actuator, is installed on the bypass line between the inerting gas pipeline and the mast riser. In automatic mode, the actuator modulates the valve position in response to a control signal from a pressure transmitter, to control the vapor pressure in the cargo tanks. It complies with the latest international rules and regulations, and has an advanced reporting system, according to the manufacturer. Its wide ambient operating temperature range (from –20 to 65°C) makes the system versatile in the exposed conditions experienced by oil tankers at sea. — Rotork PLC, Bath, U.K.