How do you manage the balancing act between maximum flexibility and efficient production? The answer can be found in the newly built Rowe Mineralölwerke (Mineral Oil Refinery). More than 500 different oils are produced in this ultra-modern production and filling plant. To ensure safe operation of the tanks and other equipment as well as accurate disposition of raw materials, more than 200 level sensors from Vega are installed in the plant.
Each bank is equipped with a continuous level transmitter (VegaFlex 81)
in combination with a VegaSwing 63 as overfill protection.
Rowe Mineralölwerke must have removed the word ‘slow’from its vocabulary: there is no other way to explain how, within only eight months, the company built a production facility for motor and industrial oils, high-performance lubricants based on renewable raw materials and other lubricants. In a space of around 82,000 m sq in Worms, Germany, there are nearly 225 tanks, 32 mixing vessels and six ultra-modern filling systems that are all connected through an ingenious pipeline concept.
To achieve a high level of safety, yet great flexibility at the same time, some 250 pumps and 2,800 valves had to be installed in addition to the 65 km of pipelines. This allows approximately 500 individual products to be produced in defined quality and filled into containers according to customer specifications.
Rowe has been in business for 20 years. Thanks to company founder Michael Zehe, the company succeeded in realising annual growth in the double digits during this time. “Like many entrepreneurs, he started in a garage —and fast has always been his way of doing things,”explained Dr Thomas Nießen, authorised officer at Rowe and co-responsible for the planning and implementation of the new plant. “When we start something, we like to finish it quickly.” The old plant in Bubenheim, which now focuses on the production of industrial lubricants, brake fluids, radiator antifreeze and car care products, had an operating license for a staggering 60,000 tonnes per year, but the new plant has one for twice that amount.
The Project Takes Off
Thanks to the plics concept, installation and setup of the many instruments
went fast and smooth.
In March 2013, the company Göhler in Hoesbach took over the planning of the facility; the actual realisation started six months later. Production of the first oils was planned for the first quarter of 2014. “From the very beginning, Rowe had a very clear idea of what the plant should look like,”recalled Oliver Binz, project manager at Göhler and responsible for the planning and implementation of the plant. “The quality of the final product is extremely important, therefore, mixing should be done as late as possible in order to avoid cross-contamination.”
At the same time, the costs of cleaning pipes and mixing tanks should be as low as possible. At first glance, it is the sheer multitude of pipes that is especially impressive; more important, however, is how they are interconnected. Every step in production is monitored via Profibus with the help of a process control system. The base oils and additives are first delivered by tanker trucks and stored in aboveground multi-chamber rectangular tanks. At this point, the sensors come into play: in each tank there is a continuous level monitoring system, complemented by a separate overfill protection system. The entire system complies not only with the requirements of the Federal Water Act (WHG) and the VAwS (Ordinance on Systems Handling Materials Hazardous to Water), but with many others, such as the Technical Regulations for Water-Polluting Substances (TRwS) or General Plant Safety (TRBS).
The raw materials are conveyed to the mixing vessel and mixed according to formula. The special feature here: every additive can be fed into any tank. At the end of the process, the finished product is shipped in tanker trucks or filled into containers.
Reliable Level Measurement
Also impressive is the vast armada of level gauges. Vega delivered for all 225 tanks a continuous level measuring system (VegaFlex 81) in combination with VegaSwing 63 as overfill protection. Continuous measurement is applied for raw materials disposition or for inventory. In level measurement with VegaFlex 81, microwave pulses are guided along a cable probe and reflected by the product surface. The measuring probe of the TDR sensor ensures that the signal travels down to the product undisturbed.
VegaSwing 63 detects the limit level reliably and with millimetre accuracy. The vibrating level switch is the ideal level detector for all liquid media, regardless of their viscosity. Users appreciate its exact switching point because it allows them to utilise the maximum volume of the storage container and thus store the product efficiently, even if the product changes from time to time.
Also when it came to level measurement, it was obvious that Rowe knew exactly what it wanted. “We had very good experiences with Vega instruments at our plant in Budenheim and therefore explicitly insisted on having Vega instruments installed in the new plant,”explained Dr Niessen further.
Fast Setup And Commissioning
Altogether there are 225 tanks in which raw materials and end products are stored.
“The installation of the instruments went without a hitch,”noted Mr Binz. “This is certainly due to the plics concept —the user interface is always the same, which made it very easy for the setup technicians. We also appreciate the close and uncomplicated collaboration with Vega. For Mr Binz it is important that, when such problems arise, he can talk directly with service technicians and not just a hotline.
Another advantage of the instruments is, in his view, the removable display. “Here we can really save money. After all, not every level measuring point requires an on-site display at a dizzying height, and certainly not in the Rowe plant. But when commissioning or later servicing, it is very convenient to be able to mount the display briefly and then remove it when you are finished,”said Mr Binz, speaking from experience.
Measurement Of Highly Viscous Media
Besides 65km of pipleline, approx. 250 pumps and
2,800 valves and hose coupling stations were needed.
The installation and measuring conditions were not at all simple, especially in the tanks that hold highly viscous additives. This is because of their structural features: these tanks are partitioned internally and provided with struts for stabilisation. When such a tank was filled under pressure from the tanker truck, the resulting pressure surge would buoy the cable probe of VegaFlex upwards and cause it to wrap around these struts. However, a solution to this problem was quickly found. Heavier tightening weights on the cables now ensure that the measurement of highly viscous media is reliable and accurate.
Without a doubt, the Worms-based company will keep doing things at a fast pace. The operators are very satisfied with the facilities already running and also with the installed level instrumentation. “Almost everything is now functioning. And that is not always so with projects of this magnitude,”said Dr Nießen in conclusion. The smooth, trouble-free setup and commissioning of the level sensors certainly contributed a lot to this success. Dr Nießen is in any case convinced that if the company undertakes a similar project again in the future, Vega sensors will be an integral part of it.