Automation improves rapeseed oil production
Polish edible-oil producer moves to digital plant architecture, creating a highly efficient plant with lower operating costs. A very small in-house automation team can accomplish great things with the right tools.
Piotr Burgs, Emerson Process Management
When ZT Kruszwica wanted to implement full automation its new rapeseed oil processing plant at Kruszwica, Poland, it implemented Emerson Process Management’s PlantWeb digital plant architecture with DeltaV digital automation and HART-enabled intelligent devices. Compared with the previous plant, this significantly reduced the use of all utilities, cut maintenance costs by 50%, and produced one of the company’s most efficient vegetable oil processing sites worldwide.
Poland is the seventh largest producer of rapeseed oil worldwide and has a large domestic market for edible oils. The main producer is ZT Kruszwica, a subsidiary of Bunge, the world’s largest producer of oilseed and bottled vegetable oils. In Poland, ZT Kruszwica is the leader with a 32% market share. The company produces products for a broad range of customers as well as its own brand, Kujawski, the country’s leading bottled-oil brand.
(Kujawski uses some highly creative TV advertising in Poland, including this spot that gives a very fun and fascinating, if somewhat technically inaccurate, interpretation of how oil is produced. The second part of the video shows how the computer generated images were created and blended with live action. --Ed.)
The company distributes margarines and shortenings for food service and commercial applications in Poland and local EU markets, and is an important supplier of rape meal, a valuable component in animal nutrition. In 2006, ZT Kruszwica bought 397.9 thousand tons (25% of the total domestic crop) of top quality rapeseed from plantations using certified sowing material.
Replacing outdated technology
ZT Kruszwica currently operates oilseed processing plants in the Polish towns of Kruszwica, Brzeg, and Gdansk. The Kruszwica plant was acquired from the State Government in 2001 by Cereol, a French oil processor. At that time it was one of the most automated plants of its type within Poland. However, the process equipment dated from the 1950’s and the control consisted of manual or pneumatic valves with very simple, outdated PLC’s. Rather than upgrade the original Kruszwica plant, the state government required that the new owner make a major investment in a greenfield plant located on the other side of the road from the original location. In 2002, Bunge acquired a controlling stake in Cereol, and inherited the project.
With the purchase of the existing facility in 2001, Cereol acquired roughly 60% of the Polish market. The trade-off was that it would implement a new and more efficient facility. The plant needed to be competitive in the global marketplace to ensure that production would stay in Poland for the foreseeable future, while also increasing the possibility of being able to expand into exports to other countries in the EU.
To reinforce the company’s leading position in the vegetable fat market, cutting edge process engineering was stipulated for the new installation along with a fully automated plant incorporating advanced process control architecture. The plant needed to be extremely efficient and economical to run. ZT Kruszwica was keen to streamline operating costs, and implement a solution that would optimize process parameters, thereby reducing energy and utilities usage.
GMP for food products
ZT Kruszwica also wanted to ensure consistently high product quality, in line with their Good Manufacturing Practice (GMP) policy. The aim of this policy is to control and manage production processes to ensure quality and traceability of the products. The company was therefore looking for a solution that would combine tight, accurate process control with outstanding traceability.
Tight control ensures minimum process variability, which reduces off-spec product and other quality problems to lower waste and rework. Moreover it reduces the impact of production processes on the environment. The ZT Kruszwica environmental policy aims to reduce water consumption and wastewater, as well as other wastes according to European standards and to minimize atmospheric emissions.
To meet these stipulations, a fully automated plant was required, supported by plant architecture that applies open communications standards to link the large number of monitoring and control devices, systems, and applications in a plant-wide network. This approach ensures critical plant operational data is available wherever it's needed. Jacek Brauer, ZT Kruszwica plant automation specialist/automation project team leader, took on responsibility for providing the automation control solution for the entire facility, including the full range of processes within the plant.
Launching automation updates
In 2002, ZT Kruszwica selected an automation solution based on Emerson’s PlantWeb digital plant architecture, with a DeltaV automation system and HART communications designed to network intelligent devices throughout the plant.
HART offered the company an easy means of making real-time changes to the range and units of measurement devices. HART digital communications was selected with future developments in mind and because it was seen as the natural progression from 4-20 mA without overcomplicating things. Instrumentation engineers wanted to ensure that any modifications or changes required could be made quickly and easily onsite. Additionally, a number of HART transmitters were used in the original plant.
Brauer was convinced that using digital architecture would deliver greater efficiency than the PLC based systems he had evaluated. When it became apparent that every single process across the plant could be controlled and configured from a single engineering station, Brauer felt that it was an easy choice. Nonetheless, he wanted to retain operator control, giving them the ability to manage and drive the process themselves.
The company also had a few additional requirements:
• It was essential that the automation solution complied with IEC61131-3 for sequential diagrams within one configuration environment and one database.
• The system had to be very stable and easy to implement and maintain.
• An efficient start-up was important to generate faster return on investment.The solution must not create additional cost to keep the plant running.
• There should be no additional external engineering costs for new projects or modifications to the existing set-up.
The new Kruszwica plant has seen production almost double from 700 to 1,300 tons per day compared with the old plant. This has been achieved largely because of the new machinery installed, including a larger extractor. The digital architecture is helping to improve production further. With access to much more measurement data, ZT Kruszwica has been able to identify bottlenecks in the process which they have subsequently addressed to improve output.
Emerson’s DeltaV automation system has played a key role in helping to reduce variability in the process. By providing easy access to trend data, the system makes it possible to spot deviations from optimum levels in the process quickly. Using this information, Brauer has modified and improved the algorithms run by the system, optimizing the process more effectively. This has meant ZT Kruszwica has been able to run the plant closer to its maximum capacity without compromising end product quality.
In some parts of the filtration and bleaching processes, this has resulted in improvements by up to 50%, and since its start up, production at the new plant has increased by 10% as a result of reducing variability in the production processes.
“These improvements are significant and demonstrate the value of using a sophisticated automation solution that delivers tight control and greatly improved accuracy,” said Brauer. “It is extremely easy to implement the new algorithms so we can make improvements to the process very quickly.”
Finding specific savings
The new plant with its digital architecture has helped save valuable resources, reducing the amount of raw materials and utilities used. For example, hexane consumption and the use of bleaching earth have been reduced by 25%. This is as a result of constantly improving the programs run by the DeltaV system. A new closed loop system that returns water back into the process has decreased water use by 75%.
An essential requirement of any food or beverage processing plant is the ability to provide easily accessible, high quality historical production data to ensure product traceability and safety. The historical data also supports ZT Kruszwica’s integrated quality system which is compliant with the international standard, ISO 9001:2000 and contains Hazard Analysis and Critical Control Points (HACCP), a systematic preventive approach to food safety. Emerson’s DeltaV gives easy access to historical data for operational and other management functions, such as reporting and billing. The system collects all necessary data and information within its historian software to provide product traceability. Its flexible reporting functions meet the complex requirements of a wide variety of internal and external customers, including Certificates of Analysis. There is also the ability to integrate enterprise level systems including enterprise resource planning (ERP).
“Meeting requirements for traceability is extremely important to us, but the additional benefit provided by the DeltaV automation system was easy access to highly valuable data stored within the historian,” says Brauer. “We use this data to analyze the process, and identify malfunctions or areas for improvement. Every single measurement and action throughout the entire process is now recorded.”
Automation control is an excellent tool to help reduce human error, which can easily degrade end product consistency and quality. The automation system uses sophisticated algorithms written by Brauer to optimize the process, thereby reducing energy and raw material losses while maintaining consistent quality.
Automation improvements are also helping to save energy at ZT Kruszwica. One example is the introduction of new temperature measurement points on the heat exchanger. Four temperature transmitters are now used where only one was in place previously. The increased data made available from these additional instruments showed that the heat exchanger was only 50% efficient. By making improvements to the program running this section of the process through the automation system, the plant increased efficiency to 90% and resulted in energy savings of 1,300 GJ a month, which amounts to € 77,000 annually.
As part of the digital automation solution, intelligent devices are used to measure and monitor all aspects of the process from extraction right through to final product. This includes continuously measuring oil flow and density, controlling various chemicals and gases used during the degumming, caustic refining, and bleaching processes, as well as the utilities. The temperature and level of the oil within the final storage tanks is monitored and the amounts of product delivered to the customer are calculated for custody transfer.
A complex process
Cleaned and dried rapeseed, obtained mainly from domestic producers, is stored in 18 large (40 m high) concrete silos on site. Following preconditioning, the rapeseed is crushed, flaked, and heated before screw presses extract the highest quality virgin oil. The remaining seeds then pass through a solvent extraction process to obtain the final 8 to 10%. This is processed separately from the virgin oil. The remaining by-product after extraction is rape meal which is used in animal feed.
Crude rapeseed oil, straight from the crushing operation, is very bitter due to its high natural acid content. In that form it is not considered edible and requires extensive processing to provide a commercially acceptable product. The crude oil passes through a series of purifying processes. First, it is heated and intensively mixed with phosphoric acid to optimize precipitation of gums and trace metals. Next, it goes through a caustic refining process where a caustic soda solution is mixed with the conditioned oil. This neutralises the acid as well as free fatty acids in the oil. The caustic reaction creates soap which is washed out and used as a feedstock for soap manufacturing.
Once neutralized and washed, the oil is treated with bleaching clay to remove any remaining color impurities and residual material. Finally, the bleached oil is deodorized, resulting in a product with a commercially acceptable flavor and color. The process provides odorless clear oil, with a slight light golden tint. Liquid oil can be bottled at this point, or delivered for hardening. Here a catalyst and hydrogen is introduced to produce a solid product that undergoes blending to create a final product. Hardened oils serve as a base component for margarines and vegetable fats at the margarine processing plant, also situated onsite.
From these processes one stream delivers liquid oil to the final product tank farm and a second stream delivers the solid oil to a separate facility. The liquid oil storage tanks are heated, especially in the winter months, to maintain optimum oil temperature, so that it remains stable and in the best possible condition. There are 50 final batch tanks, each containing finished product with specific variations in color, odor, and consistency, depending on specific customer requirements. Depending on demand, ZT Kruszwica produces a total of 50 to 60 types of end product, including two main variations of bottled oils (pressed and extracted), and a range of margarines and food ingredients. In total, around 100,000 tons of liquid oil, 50,000-60,000 tons of margarine and 40,000-50,000 tons of food ingredients are produced annually.
The Kruszwica plant is unusual in that it produces a very broad range of final products for a number of external customers. Although the plant runs as a continuous process it uses a quasi batch system with many sequences to produce different types of final product. These are then sent through a unique system of pipes, junctions, and control valves to separate batch tanks for different customers. This process is fully automated, using over 100 Baumann and Fisher control valves, and over 950 ON/OFF valves fitted with Emerson’s El-O-Matic actuators, all controlled by the automation system. The system delivers a very efficient and clean final distribution environment.
The system has 6,200 I/O and 1,000 HART devices, including transmitters and valves. For example, due to their capability to handle dirty, raw oil, ZT Kruszwica chose Micro Motion Coriolis mass flowmeters throughout the process, in preference to the variable area meters they had previously used. Coriolis meters are also used to measure flow and density of the crude oil moving between refining steps because they are accurate, reliable, and simple to use. Utilities are measured by Rosemount vortex flowmeters and magnetic flanged flowmeters.
Rosemount 3144 temperature transmitters and 3051 pressure transmitters are used to meet HACCP requirements. The dual sensors on these devices mean that rather than having to recalibrate to comply with legislation, DeltaV calculates the difference between the two sensors, effectively allowing one to audit the other.
In total, maintenance costs are 50% lower than for the previous plant. The new high-quality measurement and control devices have been a significant factor in this reduction as they require less servicing. The new automation solution has removed the need to monitor devices, and new procedures have been put in place to address problems quickly and efficiently.
“We have installed measurement points absolutely everywhere in the process, and using the DeltaV system, we are able to quickly identify if there are any problems with individual machines such as pumps,” commented Brauer. “We do not have time to monitor all the devices separately in real time, but we can look at measurement data trends to quickly identify and rectify faults.”
Once the required amounts of finished oil are sent to the various batch tanks, they are sold to customers using one of two methods. The product can be delivered in bulk by oil transfer using trucks or rail cars, or bottled and packaged onsite. In both cases, oil taken from the tanks is measured using flowmeters, and the volume data is sent via HART and recorded in the system. The system can provide the information required to print a receipt for the amount of oil delivered, and from this an invoice is produced. The Kruszwica site also has a bottling facility where measured oil is bottled and packaged to the customers’ specification. Solid products, such as margarine, go to a facility for packaging. Pressurised nitrogen forces the solid product through pipes to the packaging facility.
A small automation team
Because the entire automation project was undertaken largely by the two-man team of Jacek Brauer and Zbigniew Klesyk, it was very important to get support from the supplier while configuring the control system. At the same time, ZT Kruszwica was keen to keep the unique production process and control set-up in-house rather than tender the work out to integrators or even control equipment vendors. So Brauer undertook the majority of the programming and set-up himself. This was only practical because of the digital architecture and the ability to communicate with the HART devices out in the field.
Brauer launched into the system programming after only a one day configuration training session. He found the sequencing language of the system very easy to adapt to their needs and was able to create his own programming tool to generate a control strategy automatically. Microsoft Excel was also used to speed up the set-up for similar parts of the process. DeltaV generated 80% of the configuration files automatically and the simulation feature significantly decreased the time needed to create the code, resulting in extremely short start-up times. All the measurement devices were preconfigured using the parameters the company supplied.
Prior to start-up, Brauer used AMS Suite predictive maintenance software to ensure that devices were installed and configured correctly. This helped accelerate commissioning and contributed to a successful start-up. If there were problems it was possible to query the system to display instrument and valve data by plant location, physical network, or other criteria. This was a powerful tool for the small ZT Kruszwica team, as it allowed their in-house staff to configure individual sections of the plant within two days.
The maintenance software now checks for sensor errors with flowmeters, and it checks and recalibrates level devices. It is also used to monitor the health of critical devices, especially those in hazardous areas. Within hazardous zones it is difficult to remove transmitters, so AMS Suite has made it much easier to reconfigure them.
Emerson provided full support during the initial start-up of the plant for field equipment, but ZT Kruszwica was confident enough to handle all aspects of the control system and to modify the system themselves without any need for onsite support.
“The fastest start-up, which included about 250 I/O points, took just two hours and was completed by one of our staff without help from either an automation specialist or a programmer,” Brauer notes. “We started 30 new processes within three years with just a two man engineering team, and on each occasion the capabilities of DeltaV significantly reduced the start up time.”
Expanding technology choices
Having made the decision in 2002 to base the digital architecture principally on intelligent devices incorporating HART connectivity, there has subsequently been a gradual move to incorporate other communications technologies. In 2004 a decision was made to install Foundation fieldbus networks connecting mass flow meters within the refinery section. This enabled ZT Kruszwica to gain experience of this alternative technology.
The fully automated plant is enabling ZT Kruszwica to get the maximum from the facility and to increase production. Placing the process fully in the hands of the operator has enabled ZT Kruszwica to optimise production levels while ensuring consistently high-quality final product. In addition, the use of energy and utilities has been reduced. The ability to access historical process data combined with ZT Kruszwica’s desire to improve production continuously will see even greater results in the future.
Piotr Burgs, Emerson Process Management
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