Our feature shows examples of how electric valve actuation technology from Rotork is being used in two different, yet equally arduous, applications
The recently opened Botlek Tank Terminal (BTT) at Rotterdam is using Rotork’s electric valve actuation technologies for automated flow control and safety related duties associated with the import, export and storage of liquid bulk products.
The construction of the first phase of the terminal began in April 2010 and was completed within budget and on time. BTT has 34 storage tanks, providing a combined storage capacity of 200,000 cubic metres, of which 130,000 cubic metres is earmarked for clean fuels and the rest is for edible oils and biodiesel. Over 250 Rotork IQPro multi-turn and quarter-turn intelligent electric actuators have been installed to operate the valves that control the routine movement of liquids throughout the site. A further 55 Rotork Skilmatic SI self-contained electro-hydraulic actuators have been installed in strategic areas on valves that provide failsafe Emergency Shutdown (ESD) protection from potential accidents and spillages. The actuators are monitored and controlled on fully redundant Rotork Pakscan digital bus loops, linked by three Pakscan P3 master stations to the site’s central SCADA system.
The Skilmatic SI actuators have an integral circuitry designed to receive a separately hardwired discrete ESD alarm signal that will override any other input and move the actuator to the pre-determined safe position, even in the event of electrical power failure. The actuators are key components in the Terminal’s Safety Instrumented System (SIS).
BTT general manager, Charles Smissaert, pointed out that this solution had been selected as a more robust and reliable alternative to air operated actuators, which also require more maintenance.
All Rotork actuators at BTT feature ATEX explosion-proof certification and IP68 double-sealed watertight enclosures designed for harsh and exposed environments. They also share Rotork’s IQPro non-intrusive setting, commissioning and data communication technologies, enabling actuator configuration and data logger files to be transferred from the field to the office for diagnostics, analysis and storage.
Rotork BV’s local workshop provided the facilities to motorise all the valves, including gate and butterfly designs in sizes up to 16 inches, before shipping them to site as complete, factory tested packages. Rotork also assisted with installation and commissioning.
In a separate application for Mineral Engineering Processes (MEP), Rotork CVA electric control valve actuators are fulfilling the requirement for critical flow control on the company’s TBS Hydrosizer machinery. The machine is used in the mining and mineral process industries to separate materials, remove contaminants and beneficiate mineral particles that are generally less than 5mm in size.
The TBS Hydrosizer process uses an upward current of water to create a hindered settling classifier in which material within a narrow size band can be held in a state of ‘teeter’. Smaller or lighter particles entering the classifier are displaced to the overflow, whilst larger or heavier particles migrate to the bottom and are discharged. Applications include coal preparation, the preparation of high-grade sand for concrete products, glass making, foundry use, and many more.
A well defined separation is achieved by maintaining a constant flow of upward current water, even though the level and nature of the mineral content in the water can cause the density to fluctuate. A 4-20mA signal from a hydrostatic density probe within the Hydrosizer Tank controls the CVA actuator operation, maintaining the constant flow of material. The CVA adjusts the position of a valve, allowing material to discharge at a rate that is determined by the hydrostatic head.
With resolution, repeatability and hysteresis performance quoted at less than 0.1% of full scale, the swift response and positional accuracy delivered by the CVA actuator improves process efficiency. In addition, integral super capacitors enable failsafe operation of the CVA to close the valve on loss of mains power or loss of control signal to prevent product damage or contamination.
Rotork Process Controls