Not surprisingly, refining vegetable oils is similar in many ways to processing crude oil and gas. The plants also share many of the same goals and challenges—along with the same satisfaction when a clean, high-quality product is produced.
To reach this objective, however, there can many obstacles to overcome, including simplifying historically cumbersome and costly process automaton controls and software, according to Camilo Guevara, automation manager for North America, Desmet Ballestra, a Belgium-based designer and builder of equipment and facilities for producers of vegetable oils, fats and oleochemicals located worldwide.
Seek better screens
"We installed it, the customer was happy, and we've standardized on PlantPAx." Camilo Guevara of Desmet Ballestra discussed the advantages of using a DCS approach to develop logic and operator displays.
Most of the equipment and components are supported by human-machine interfaces (HMI) and process objects, “but it can be a challenge to develop and maintain them because we have screens from Wonderware, RSView 32, Siemens Portal, FactoryTalk View and others, and we've had to build another library of objects and faceplates each time a new software comes along," explained Guevara. "We build screens for PID control, auto-tuning, transmitters, alarms and trends, and modify them as needed. We've also basically used the same FactoryTalk library for nine years, but each customer wants the HMI for their vegetable oil deodorizer to look a certain way based on their individual application, and we need to satisfy those requests in-house."
Guevara presented "From Development to Start Up in a Vegetable Oil Refinery" at the Rockwell Automation Process Solutions Users Group (PSUG) 2017 meeting this week in Houston.
"Desmet Ballestra covers each step of the industry, from oilseed preparation and extraction to oil processing plants, including refining and fat modification processes," said Guevara. "It's mastered processing of 40 raw materials, of which soybeans, palm oil, sunflower seed, rapeseed, groundnuts and cottonseed are probably the most popular. Covering more than 8,000 process sections, the group has supplied small and large plants to some 1,700 oil millers in 150 countries."
One of the primary systems Desmet Ballestra builds are deodorizers, which are basically large distillation columns that can be 90 feet high and 7-13 feet wide. "Deodorizers let users control the percentage of trans fats in their oils, and further refine them," explained Guevara. "What our customers are seeking is a bright, clear and odorless vegetable oil, which can present challenges for plants that typically produce 50-1,000 tons per day or more of vegetable oil."
To construct and implement plants for its clients, Guevara added that Desmet Ballestra specifies and supplies valves, instruments, motor control centers (MCC), control panels, HMIs and computers, including panels and devices for use in classified and hazardous locations that need intrinsically safe (IS) barriers. These are needed because soybean applications typically use hexane in their separation process.
Simpler with PlantPAx DCS
"We wanted to focus more on our vegetable oil equipment, and leave coding of software objects and following standards to the experts," added Guevara. However, after adopting an initially promising DCS software package, Guevara discovered that it wouldn't work with earlier versions; that its DCS and PLC/HMI software were incompatible and couldn't even be installed on the same computer; and it required tens of thousands of dollars in added upgrades and other costs.
Fortunately, while recently building a plant in Mexico, Guevara reported that its customer suggesting checking out the PlantPAx DCS, and they were quickly convinced of its advantages. "With PlantPAx, the DCS software and PLC/HMI software are the same. This means we can use the same PC and object library, and even the new library is free," he said. "The price to upgrade to a newer version was the same if a TechConnect support agreement was in place, and the price of using older software versions for development wasn't an adder. PlantPAx can also use several kinds of small and large controllers, though some added memory may be needed.
"In addition, many programmers were already working on the PLC/HMI, so transition was easier. I took courses, and developed a full PlantPAx application from scratch in just one year. We installed it, the customer was happy, and we've standardized on PlantPAx."
Other simplifications and benefits of the PlantPAx DCS include:
- Network communications via one EtherNet/IP protocol, instead of up to three protocols before;
- Free library of process objects from Rockwell Automation instead of using resources to develop an in-house library; and
- Ability to use only periodic tasks in the PlantPAx system, instead of being restricted to only a few periodic tasks, and having to rely on continuous tasks before.
"We're also using the process strategies/import tool in PlantPAx for many functions like valves, which is key to reducing our development time," explains Guevara. "The code is pre-made for you. You just import it and change the tag, which just takes a few seconds. We can create an object such as a motor at least four times faster than before. And, all we need to do to link it is put in one line, so the tag can be read by the PLC. It's very easy."
Guevara added that he recently created a "skeleton" for a deodorizer system that consisted of objects for 100 valves and transmitters, and that with the PlantPAx DCS, all he needed was a way to connect those objects, which he accomplished with software-defined interlocks. "Now, we just click on objects to get faceplates, and faceplates for maintenance," he added. "We can still do our own programming when needed, but it's a big help to have software blocks available for displaying valves, transmitters and other devices. Also, with PlantPAx, we can add a wireless access point, and get a secure, remote-access display of the actual HMI, which speeds up I/O checks."
