| When RFID is used in chemical processing environments, it offers functionalities related to liquid products and incorporates quality as well as quantity measures. |
By Wally Klatch For liquid products, RFID technology can offer an opportunity for major improvement in the chemical supply stream. The astonishing fact about radio frequency identification (RFID) technology — well known as one of the hottest topics for discrete items — is that chemical process industries can use it to reduce costs, improve efficiencies and increase the sustainability of supply streams. In fact, RFID for liquid products is way ahead of the RFID curve for discrete items. While the technology and ROI calculations for RFID in the discrete world are still works-in-progress, the RFID techniques for liquids described in this article are based on proven, widely used logistics techniques. In discrete environments, RFID involves the placement of a small tag on each product unit and the reading of those tags by readers throughout the production, distribution and sale/usage processes. It allows real-time tracking of inventory movement and makes supply chains more effective by having the right product at the right place at the right time. In chemical process industries, RFID should not be viewed as tags, readers and the systems that connect them but by the specific functionality it can offer. RFID in chemical processing can provide real-time information regarding the quantity in stock of a specific product, the location where the product is held and product movement from location to location as well as minimal or no manual input to get this information. An environment that provides all these functionalities fulfills the definition of RFID, even if it does not include all the physical elements commonly associated with an RFID system. Let’s look at how the equipment for holding and moving chemicals can be set up to meet the profile of an RFID system. First, how can you know how much product is in stock if you don’t count it or put an RFID tag on it? In a liquid-designed system where product is held in tanks, a specific tank is defined as holding a specific liquid at any given time. While this assignment may change over time, the tank-liquid relationship at any moment is 1:1. RFID, in this case, identifies the material by the tank in which it is held instead of by a tag. Second, how can you obtain real-time information on the quantity of product in stock as well as the location of the stock? When a certain tank is defined as holding a specific liquid, a liquid level sensor can detect the quantity of the liquid in the tank at any given moment. Since multiple tanks can hold the same liquid, the total balance of the tanks yields the total balance of the liquid in stock. The location of the tanks holding a particular liquid is equivalent to knowing the location in which the liquid itself is held. It is assumed that a specific location (tank) always holds a certain material unless, for example, a specific tank is switched from one liquid to another. If a more direct product identification method is needed, or if there is need to segregate and identify specific batches of a product, several methods are available including taggants and chemical markers. Taggants are tiny pellets or tracers that are introduced into a liquid and which may be “read” at any point to identify the liquid. In a sense, a taggant is like an RFID tag that actually becomes part of the liquid product. Alternatively, chemical markers that may be identified through chemical analysis or sensors may be used so that a specific product or batch of a product may be identified at any point in the operational flow. When RFID is used in the chemical processing environment, it offers additional functionalities related to liquid products. RFID can incorporate quality measures in addition to quantity measures. Just as liquid level sensors measure quantity, various quality-related sensors, such as temperature and oxygenation monitors, can provide continuous information that allows constant monitoring of the quality of the liquid product. The RFID functionality of recording product movements is handled differently under a liquid-based approach. Traditional RFID methodology calls for tagged items to pass in proximity to a reader and for the reader to record tag movement. For liquid products that move through pipes from a source into a tank or between tanks or from a tank to a point of dispense, a flow meter records the quantity of product as it moves past the metering device. Like an RFID tag reader, a flow meter can capture information, such as time of day, together with each product movement in order to provide movement history, auditing and traceability. Another advantage of RFID in chemical processing environments is there is little or no manual input required to achieve complete, real-time data capture. Liquid level sensors and flow meters working through PLCs or other data capture-and-transmission devices need no manual intervention. While a one-time definition is necessary to assign a specific liquid to a specific tank, this is less than the continual manual effort required to define, prepare and affix RFID tags to each unit of product to be tracked. For chemical equipment engineers, this alternative approach to RFID represents an additional tool in the product flow toolbox to create the best and most successful solution for any particular application. Having choices means having power, and alternative approaches to RFID enhance rather than challenge the role that RFID can play in chemical process industries.
About the Author: Wally Klatch, vice president of operations of LiquiChain, is a supply chain professional with more than 25 years of experience designing and implementing supply chain solutions. His work in equipment specification and data flow design spans the chemical, beverage, lubricant and cleaning solutions industries. He founded the Supply Chain for Liquids and RFID for Liquids disciplines and wrote the book, “Supply Chain for Liquids: Out-of-the-Box Approaches to Liquid Logistics.” Questions about this article can be addressed to him at [email protected] or by calling him in his New York office at 914-595-4723.