Evaporation and Spray Drying Optimisation

Transcription

1 Evaporation and Spray Drying Optimisation Solutions for Food Powder Industries Based on modelling techniques, our solution reduces variability in the production of food powders and offers a significant increase of average humidity, resulting in substantial economic gain. It allows operators to detect deterioration issues in industrial processes, and thereby to remedy issues rapidly to avoid breaks in production.

2 Operational and Energy Efficiency Evaporation and spray drying equipments in the food industries is generally multi-function mass production systems. These systems can be used independently, or in a complementary manner. In any case they are designed to transform a liquid into powder form with preestablished residual humidity, density and functional properties. The core goal of the production team is to maximise production and output while providing guaranteed quality of the final product in order to adhere with project specifications. Meeting these objectives is a real challenge given that many industrial equipments such as evaporators and spray dryers are often used in operating conditions far removed from their original design parameters. Furthermore, raw material characteristics as well as output rates can be highly variable. Thankfully, the recent technogical advances made in the field potentially offer new opportunities, in particular regarding online analyses of humidity levels and particle size. These new techniques allow for automated testing of final product characteristics, making the quality control process simpled and more efficient. Operations: What is at Stake A successful launch is the first and most important stage of the operational process. The launch process is often a strict sequence destined to allot equipment units to specific slots in a pre-established schedule. This is a critical stage: a faulty launch can disrupt units and cause operational issues that can span the entire production campaign. Once the schedule has been established, the evaporator and spray drying equipments must cope with disruptions caused by: variations in the density of raw materials, steam pressure, and ambient temperature and humidity. These disruptions have a major impact on performance as they affect normal operating conditions. During this stage, the operator must compensate for these disruptions in order to keep the installation optimised in financial terms this can be a dauntingly complex task. The real stakes of operations is avoiding breaks in production which can be triggered by a multitude of causes related to the processes themselves. These causes include: vacuum leaks; misaligned analyser results; powder accumulations and even clogging in evaporators; humidity in spray dryer chambers; or blockages of the fluidised bed. 3 to 6 months Corresponds to the average return on investment when adopting our solution

3 Tried and Tested Solutions Our solution is a real-time, integrated system compatible with all types of spray dryers. It can easily interfacing with existing control systems and offers a number of advantages: Return on investment in 3 6 months Variability in powder humidity levels is reduced after drying process Humidity increase in line with final product specifications Real-time humidity level estimations Reduced powder deposits in dehydrators and cyclones Realistic and accessible training environment for new operators The predictive control and monitoring techiques for industrial evaporators and spray dryers offered by Schneider Electric and its partners helped us increase quality levels in food powders, and also helped make our processes accessible. We were able to measure a slight increase in production coupled with energy savings of approximately 10%. JL Liban Production Manager

4 Advanced Control and Diagnostics Solution Schneider Electric and its partners offer a solution to increase the operational and energy efficiency of evaporators and spray dryers based on a system of advanced control. Evolution forecast for the prediction horizon > Virtual Sensors to Measure Humidity in Real Time Measuring residual humidity in food powder is a key process. For numerous installations, there are no on-line sensors but instead periodic laboratory analyses. In situations such as these, we offer virtual sensors to measure humidity in real time. Based on a mathematical model, the virtual sensor calculates powder humidity levels based on physical measures taken during the process. Calculations are based on powerful analysis techniques such as recursive or partial regressions of least squares for linear or non-linear models (artificial neural networks). When an online analyser is set up, the virtual sensor also serves as a redundancy providing added protection. > Model Predictive Control to Reduce Process Variability The core of our solution is an Internal Model Predictive Controller that takes into account process variables, interactions between evaporator and spray dryer, and running of the buffer tank. This, our solution can reduce variability of concentrate density and powder humidity by 40 to 80%. This decrease in variability is the key to financial gain by process optimisation: powder humidity can thus be increased to meet the specifications of the final product; concentrate density can be increased; and output increased as a result. The interactions between quantities involved in the process can be described according to a multivariable model. You will be simultaneously dealing with: power and energy supply rates (to control all critical variables); compensating eventual reductions in evaporator thermal transfer capacity; and maintaining maximal evaporation rate. The density of the product treated by the evaporator is maintained at specified levels by coordinating steam recompression speeds, steam pressure, and power supply rates. The control strategy we offer accounts for variations in product density and temperature by pre-compensation. MPC Model MPC configuration With regards to this issue, the quality of the final product (dry concentrate extract) is maintained at the level specified by the operator, or at least within a narrow range. Tank levels, temperatures, output/ input rates and steam pressure valve positions are all maintained in predefined ranges. By using these range constraints, operators are free to perform other functions; in essence, the system will be optimised and decrease operational expenses. > Optimising to Increase Benefits With reduced variability in the process (thanks to the predictive controller), the optimisation system can determine the optimal concentration parameters for evaporating and spray drying processes. This may seem obvious when it is well-known that financial gain is a result of: maximising input rate, concentration levels after evaporation, and humidity of the final product. However this optimisation system takes other factors into account at all times: product density, clogging issues, and ambiant humidity levels. With these factors accounted for, the process may be pushed to its maximal potential.

5 Permanent Diagnostic of Process Status Our solution incorporates a full diagnostics service to assess process behaviour, helping operators understand, identify and compensate for deteriorations to the process and abnormal situations. The monitoring system, based on the internal model, generates basic indicators to assess the status of the process instantly. These indicators are further reinforced by an error-diagnostic system to provide a quick and accurate analysis of any situation. The real strength of our solution lies in the fact that it is capable of detecting symptons from within : process anomalies are detected even in a closed loop, whereas classic controllers tend to skip over deteriorations in such conditions. Training Simulation Our solution provides a model of your production process as built, allowing operators to learn to operate the installation and test new methods. In order to favour comprehension, the simulator generates test scenarios based on historized data (events and errors that may affect process and therefore productivity). With this tool, operators are able to pilot the installation at peak levels of productivity and output quality. We have also integrated indicators into the simulator to measure productivity, output, efficiency, and operational quality, in the hope of working towards continuous upgrades and ameliorations, and to assess performance for each operator in training. Alarm and operator information Processes & Contributions Process status Unique performance graph for monitoring Abnormal status

6 Make the most of your energy * Schneider Electric Industries SAS Headquarters 35, rue Joseph Monier - CS30323 F92505 Rueil-Malmaison Cedex FRANCE Given the evolution of regulations and materials, the characteristics indicated in the texts and graphics of this document were added only after confirmation by our services. Design: pemaco Print: 04/2011