Shelley Pike looks at how a digital wireless valve control was used on a petroleum tank farm automation project in the USA.
In 2011, an operating division of Martin Midstream Partners (MMLP) began building a single product tank farm at the Port of Corpus Christi, Texas, consisting of six 100,000 barrel tanks and four booster pumps to serve nearby truck and ship loading terminals. Originally, the facility was designed for a single hydrocarbon product and did not require any automated valves to isolate the individual storage tanks.
During construction, MMLP decided to upgrade and introduce the capability to handle a second product, which necessitated the requirement of isolating the tanks to avoid cross-contamination.
To achieve this, MMLP specified Rotork electric valve actuation under centralised control. The explosion-proof Rotork IQ non-intrusive intelligent actuators are monitored and controlled by a Rotork Pakscan P3 digital system, designed specifically for valve actuation duties and the environments associated with hazardous area petrochemical plants and storage areas. The Rotork system incorporates all appropriate interlocks which safeguard the integrity of the terminal operations.
For this project, MMLP has been able to take advantage of additional functionality and further economies through the introduction of Pakscan P3 with a wireless field network.
Wireless Pakscan eliminates virtually all the costs associated with the installation of wiring, cable ducts, safety barriers and associated equipment required for network cabling, whilst enabling an increased level of information from the actuators to be communicated over the wireless network.
Chris Duke, Rotork's lead service technician on the project, explains: "The customer didn't want to add a lot of new conduit and wiring to control the actuators, so the wireless Pakscan system was a perfect fit.
"The installation consists of 16 Rotork IQ40 non-intrusive intelligent actuators, one Pakscan P3 wireless master station and three network repeaters, which are used to overcome radio black spots and ensure the redundancy of the network. As far as start-ups go, this was by far the easiest of any type of control system that I have seen.
"Some pre-commissioning of the wireless system was performed at the Rotork factory in Rochester, NY, prior to delivery and, once in the field, I installed the wireless antennas on each actuator and gave each unit its unique address. When this was done I powered up the master station and, as if by magic, all 16 actuators populated the network within a few minutes. The customer was very impressed with the job done and how quickly everything came together."
Following the success of this project, the same actuation and control system will be extended to three additional tanks to be built during the second phase of construction at this facility.
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Shelley Pike is with Rotork, Bath, UK. www.rotork.com