Refined controls for the sugar industry

#Sugarbeetcampaign means: In the period from September to January inclusive, the sugar centrifuges sometimes run 24 hours a day, seven days a week, without a break.

The average German consumes about 35 kilograms of sugar per year. But it is a long way from the raw sugar beet to the finished product. During the "sugar beet campaign" Nordzucker AG processes sugar beet by the ton in enormous centrifuges at its plant in Nordstemmen, Germany.

From individual machines to the complete sugar factory

The complex process of sugar production requires considerable expertise, and a great deal is demanded of the associated technology. No one knows this better than the professionals at BMA (Braunschweigische Maschinenbauanstalt), who apply extensive specialist knowledge to the continuing development of their technology and an equal measure of heart and soul. With an export rate of over 90 percent, there is virtually no way that you can miss BMA in the sugar industry. "We supply everything from individual machines, such as pumps or centrifuges, to complete sugar factories," says Eduardo Lima, team leader in BMA's product automation department. "Our customers demand a lot in terms quality and reliability. That is why we only equip our machines with top-class components, such as those that we get from Siemens."

 

"We see ourselves as a full-service provider, meaning that we offer our customers everything from consulting, studies, planning and engineering through to commissioning." That is how Julius Kröger, head of marketing and communications at BMA, describes the philosophy. The important thing for BMA in this context is that the company can be "very small" and also "very large".

Reliable technology from a single source

Siemens supplies almost all the technology for the centrifuges. These include, for example, the SIMATIC S7-1200 PLC (programmable logic controller), the KTP700 human-machine interface (HMI), the control devices, the motor, the circuit breaker, fuseless load feeders (consisting of motor circuit breakers and contactors), and the soft starter from the new 3RW5 series. "We opted for the 3RW55 because we already had the excellent experience with the predecessor model. What is more, thanks to the joint development, we knew that Siemens had taken our requirements into account," recalls Han Janssen from the electrotechnical design department at BMA. "The improvements include new features such as communication via Profibus, Profinet, Ethernet and Modbus, transparent operation, compact design and hybrid switching technology." One further detail distinguishes the solution, as Han Janssen knows: "This solution is a failsafe version (Sirius 3RW55F). This means that the 3RW55F allows a safe shutdown to SIL 3 – PL e / STO. This saves us one contactor in the load circuit and ensures simple and cost-effective direct wiring of the emergency stop mushroom pushbutton to the soft starter for SIL 1."

In his view, the option of DC braking for a rapid shutdown of the centrifuge for maintenance purposes completes the range of functions. Eduardo Lima adds: "We could have adopted a solution comprising star-delta (starting circuit for large three-phase motors) or frequency converters for the continuous centrifuges. But in the case of star-delta, the current peaks can result in an overloading of the customer network. Although the frequency converter can compensate for this, it increases the cost of the overall system, which is why it is not economical. The Sirius 3RW55 offers us both reliable technology and attractive pricing."

Working together toward the optimum result

 

In particular, the collaborative partnership during the development of the soft starter makes this project something very special. "BMA was already involved in the product development phase of the new generation of Sirius 3RW5 soft starters and was also able to test the prototype extensively," explains Karl-Heinrich Schaaf, Account Manager in Vertical Sales, Food and Beverage at Siemens AG. "In a comprehensive workshop, BMA experts worked out performance criteria for the new soft starters, which we then took into account in the actual development."

 

The 3RW55 must be able to perform well, and should also be easy to use and quick to parameterize. "Our systems are used all over the world, where they come up against a variety of ambient conditions. For example, not all power grids are as stable as they are in Europe. In this respect, the Siemens soft starter has proven itself over a long period of time because it works reliably, even under difficult operating conditions," says Torsten Bockrandt, product manager for continuous centrifuges in the Software Creation, Parameterization and Commissioning department.

For me, it is important that the machine start-up is optimally controlled and the power loss is low
Thorsten Bockrandt, Software Creation, Parameterization and Commissioning at BMA

Digital solutions for global use

 

Siemens has been and continues to be a supplier to its long-standing partner BMA, and not only in terms of technical equipment. "We benefit greatly from the extensive Siemens range of advanced training for all our staff," says Bockrandt. Siemens also provides advice and support with regard to the planning of the control cabinets. "We pay close attention to convenient handling – that's what customers expect. Siemens supports us throughout the entire process with the STS simulation tool and the Simaris planning tool," explains Janssen. "For the electrical planning we use the TIA selection tool." BMA benefits on a general scale from the enormous efficiency gains delivered by the digital solutions.

 

For the future, BMA plans to continue, together with Siemens, to forge ahead with these digital solutions and approaches on a worldwide basis. For example, networking the controller with sensors and actuators will enable an even higher degree of plant transparency.