- The sugar industry campaign begins right after the sugar beets are harvested and lasts about four months. First, the beets are washed in water to which calcium oxide has been added and then coarsely sliced. Next, they go through the tower extractor, where hot water is added to extract the sucrose. The raw juice is still highly impure because it contains organic and inorganic substances. The juice goes through the carbonatation process, in which milk of lime and carbon dioxide are added to precipitate and filter out the impurities. Once washed, the juice goes through a series of evaporators and ends up as a syrup with a high concentration of sugar. After going through a crystallizer and a centrifuge, the syrup is transformed into white, crystalline sugar.
- The pH measuring points are exposed to high levels of lime depositing, high temperatures and frequent rinsing with acidic cleaning agents. However, they must operate at maximum availability since the processes cannot be interrupted while the campaign is going on.
- Fossil fuel and burning the limestone on site are two major cost drivers in sugar production. But as a result of highly available, precise pH measurement, limestone consumption and thus the amount of energy required and the level of system contamination can be significantly reduced.
Substantial savings on limestone and energy due to higher Memosens measuring point availability
pH sensors are subject to extreme requirements during sugar production. Lime is dosed based on pH measurement right from the start: during the beet washing phase, in which water is made alkaline by adding calcium oxide to neutralize the acidic soil from the field that is still clinging to the beets.
In view of the moist, dirty environment and the need to frequently clean the sensors with acids, the SE 555 pH sensor from Knick is ideal. It avoids all problems with dirty, wet or encrusted contacts, thanks to the inductive measured value transmission typical of Memosens. And the option to pre-calibrate Memosens sensors in the laboratory simply makes on-site calibration under harsh environmental conditions unnecessary.
In addition, the extensive Memosens diagnostics functions record all of the standard and operating data saved in the sensor heads. Being able to control the sensor’s operating time, sensor wear, remaining service life, maximum temperature, the adaptive calibration timer and the calibration and adjustment data increase availability enormously. Pre-calibrated Memosens sensors have a service life that is up to 40% longer in comparison to conventional products.
Depending on its distance to the main factory, an automated measuring loop with the extremely resistant, maintenance-friendly Ceramat or SensoGate sensor lock-gates from Knick, which can all be equipped with Memosens sensors, can reduce personnel expenditures for measuring point maintenance. The digitalization of the measured value inside the sensor head makes the process much easier and enables seamless measured value transmission – even for cable lengths of 100 m.
In the carbonatation process, measuring points are particularly stressed by the sticky juice extracted from the sugar beets and its initially high content of solids.
In addition to the organic contaminants, during the juice filtering process heavy lime deposits and temperatures of up to 95 °C adversely affect the measuring points.
By the end of the sugar campaign, the lime deposits can be several decimeters thick. For this reason, the sensors must be frequently rinsed with acidic solutions, a process that shortens their service life. This is the point at which the SE 555 proves itself: it has a ceramic junction in combination with a pressurized reference as protection against aggressive rinsing media.
Since the pH sensors must be checked and cleaned several times a day during the campaign, measuring point automation with the Ceramat WA 150 remote calibration probe has proven to be an excellent solution for this extreme application. In conjunction with the automatic Unical 9000 controller, the sensor is automatically cleaned with acid and calibrated at regular intervals
The Ceramat lock-gate consists of a virtually indestructible aluminum oxide ceramic that is opened and closed by rotation and a corrosion-resistant carbon-fiber-reinforced, fixed PEEK or PVDF plastic housing. Even in abrasive media, the flat sealed surface of the hard ceramic exhibits no wear.
High mechanical strength and temperature stability, as well as nearly universal chemical resistance, ensure smooth operation even under difficult ambient conditions with a high volume of dirt. To combat heavy deposits on the process-wetted Ceramat parts, the sensor lock-gate is equipped with a pneumatically operated elastomeric bellows that regularly blasts away solidified deposits at the sensor opening.
Return on Investment
- Highly available Memosens measuring points assure the continuity and quality of your processes and significantly reduce resource expenditure thanks to precise, continuous measurements.
- The pre-calibration possible with Memosens also helps you save costs since sensor service life is up to 40% longer in comparison to conventional products.
- With the combination of Memosens sensors, the Protos analyzer system and the Unical automated measuring, cleaning and calibration system from Knick, you can automate measuring loops in which conventional automation solutions typically fail due to harsh ambient conditions and heavy soiling.