Keeping an eye on all consumption

Water, carbon dioxide, steam, fuels, compressed air or electricity – food manufacturers are increasingly being confronted with the need to reduce their ecological footprint. The products and services on show at Anuga FoodTec will provide food producers with a real-time overview of all aspects of energy and enable them to identify areas requiring optimisation and to improve the efficiency and profitability of their companies.

One of the leading suppliers in this sector at the trade fair grounds in Cologne is GEA. Digital solutions that significantly reduce resource consumption during cleaning processes are of particular interest to the machine manufacturer. One example of this is the recently optimised cleaning-in-place (CIP) process in membrane filtration plants that are used mainly in the dairy and new food industries to produce milk protein or fish collagen isolates, for example. The process is used to separate or concentrate substances without thermal stress. Cleaning this plant was previously energy- and water-intensive: various chemical cleaning agents are dosed into the plant, circulated for a certain length of time using pumps and then flushed out with water. Sensors that constantly measure the permeate quality of the water during flushing are now used in order to reduce water consumption. Instead of setting blanket rinsing intervals and water quantities in advance, the Smart Filtration Flush software stops the process significantly earlier as soon as the required level of hygiene is achieved and the cleaning agents are discharged. This is able to reduce the need for fresh water by up to 50 percent depending on the type and size of the plant and the water properties.

“A typical whey protein concentration process consists of two to four filtration plants connected in series that not infrequently need more than 100 litres of water per cleaning run“, says Nils Mørk, R&D Engineer for membrane filtration at GEA. “Our tests show that we can save up to 50,000 litres of water per cleaning process in such large plants and 500 to 700 litres per CIP process in small plants.” In addition, if less water is input into the process, less effluent also has to be disposed of. “Many manufacturers can only clean their filtration plants successively, because flushing them often exceeds the pipeline capacity. That can lead to a potential safety hazard for staff and cause contamination in the production area. We can eliminate this peak water flow problem with Smart Filtration Flush, because we can significantly reduce pressure fluctuations in the water supply and drain line overflow”, says Mørk.

For producers, CIP solutions are an essential element for cleaning plants and controlling microorganisms and therefore for guaranteeing reliable process results with minimum downtimes. As in numerous other locations, the fact that the best results are achieved by cleaning with high shear forces, i.e. mechanical washing with a strong flushing flow, is also true for membrane plants. To do this, the maximum permissible pressure drop across the membranes is needed during the CIP steps – resulting in accordingly higher energy consumption. GEA is breaking with this practice and ensuring the pulsating operation of filtration plant pumps during the CIP process by means of software. “We are now transferring the process familiar from washing machines – agitating clothes in the drum, stopping at intervals and letting the cleaning agent take effect – to membrane plants”, explains Mørk. Compared directly to plants with standard pump operation at full load, small production plants can therefore save 5 to 7 kilowatt hours per cleaning process, according to the filtration expert. Thanks to this innovation, large filtration plants require 60 to 100 kilowatt hours less electrical energy per CIP process.

Software in combination with modern sensor technology is an important trend and is regarded as one of the essential solutions of developers. Continuous monitoring by sensors makes the cleaning process more efficient and sustainable. The Fraunhofer Institute for Physical Measurement Techniques IPM is demonstrating this with the F-Fiber sensor. F-Fiber consists of an optical fibre with a diameter of one millimetre that is embedded in a stainless steel sleeve. The end of the fibre is integrated directly into the wall of a food tank or a pipe conducting food. Alternatively, it can be attached to an existing fitting with the aid of a flange. All of the measurement system’s other hardware components are located outside of the plant and are connected to the production plant via the fibre. The tank or pipe content flows around the tip of the fibre on the inner wall of the tank or pipe. Over time, molecules accumulate on the sensor tip and the vessel wall. This leads to the formation of an undesired deposit. During the measurement, the fluorescence of the deposited organic material is excited with UV light via the sensor fibre. The fluorescence emission is fed back via the same fibre to a highly sensitive detector, where it is evaluated. The strength of the fluorescence signal can be used to draw conclusions regarding the extent of fouling, i.e. the deposits. Based on these measured values, the cleaning process can be triggered and adjusted in real time and in various production processes for different foods.

The fact is that food manufacturers want to save energy, water, time and cleaning agents without running the risk of compromising on product safety. However, ensuring the optimum performance of a CIP system poses many of them with a challenge. Not only do the cleaning agent concentrations in the respective cleaning step and in the reprocessing tank have to be known. It is equally important to ensure a turbulent flow, because only then is the desired cleaning effect achieved. This is where measurement technology suppliers such as Endress+Hauser come into play with a constant array of new inline devices for flow, fill level, pressure and temperature as well as for analytical measurements. Integrated directly into the application, these register data on energy, chemical and water consumption, detect the beginning and end of each cleaning step and thereby enable precise monitoring and control in real time. In this way, the sensors help to reduce the cleaning time, product losses and resources while ensuring complete traceability at the same time. Liquitrend QMW43, for instance, measures whether any deposits are still adhering in tanks or pipelines and their thickness. This multi-parameter device can register the thickness of the coating and the conductivity of the media at the same time. The device’s direct connection to the control system means that the measurement data are available in real time and enables them to be documented automatically. If the sensor no longer indicates any residual coatings, successful cleaning of the critical areas can be concluded.