Nov 19, 2008This article was originally published by RFID Update.
November 19, 2008—A liquid propane (LP) gas supplier in Malaysia has automated gas cylinder filling and tracking operations using new RFID readers that were specifically created for use in LPG facilities and other potentially combustible environments.
"We believe we have a world first -- putting RFID tags on propane gas cylinders," Mark Powell, general manager of New Zealand-based RFID developer EDiT iD, told RFID Update. EDiT iD's newly released Model 0205 low frequency (125 KHz) reader has been certified for compliance with IECEx standards for electronic equipment used in explosive environments. The system also uses RFID tags from German firm TECTUS that meet ATEX hazardous environment requirements established by the European Union.
Elpiji has implemented the system at multiple gas production and distribution facilities in Malaysia. Cylinders must be identified each time they are returned to a filling plant and released for distribution. When cylinders are returned for filling, they are identified, weighed and inspected. Operators need to know the specific tare weight for each cylinder prior to filling, so accurate identification is required. It previously took an average of 30 created to identify each cylinder, which created bottlenecks on the filling line, according to Powell. He said bar code reading was not an effective solution because symbols would often become damaged and unreadable.
EDiT iD created its Model 0205 specifically for this project and now markets it commercially. Powell said he and Elpiji decided early in the project to base the system on 125 KHz technology. Many of the UHF tags optimized for use on or around metal did not exist when system development started.
"Some of the reasons we chose LF [low frequency] were the amount of moving steel, the physical environment, the handle ring of the cylinder. Our technical assessment was that the environment in which the cylinders are filled was not conducive to UHF," Powell said. "I must admit that I have had a couple of calls on the subject of why LF was used -- all from UHF guys, who could not explain why UHF would be better than LF, and who have never tried UHF in this type of environment."
Now gas cylinders are being outfitted with permanent RFID tags that include the cylinder's identification number, tare weight, and date of manufacture, which is required to enforce retirement of cylinders who have reached their allowed life cycle (which varies according to local laws). Fixed-position readers on the filling line identify each cylinder and verify that it is eligible to be refilled and reissued according to its manufacture date. Ineligible cylinders are automatically diverted, and others are routed to the filling station, where the dispenser pumps in exactly the right amount of gas to fill the cylinder, based on its tare weight. Cylinders are also automatically routed to inspection, cleaning and other stations, and identified throughout the process. Elpiji uses production control software from Kosel Industries, which modified its system to accept RFID input.
"Using RFID, the process of accepting or rejecting a cylinder is two seconds. Compare this to a manual system where it takes at least 30 seconds, and requires a human operator," said Powell. "Elpiji's decision to invest in RFID and new filling plant software is clearly justified."
Powell said the system hasn't been running long enough to fully assess the time savings, cost reductions and other return on investment metrics. However, the time savings benefits are clear. Saving 28 seconds (the difference between RFID and manual identification) per item can significantly increase throughput for a repetitive, high-volume operation like cylinder filling. Small processing plants fill 700 cylinders per hour, and large ones fill up to 3,600 cylinders per hour, according to Powell.
Other LP gas facilities are evaluating the system, Powell said. Earlier this year several RFID professionals and users formed an association to facilitate RFID use in the oil and gas industries (see Oil Industry Forms RFID Group to Aid Adoption).
