The following scenario sounds like a fictional dystopian narrative, but it is a lived reality. A catastrophe, much like the current COVID-19 crisis, is dramatically impacting society. The normality, as was known before, has suddenly changed: streets are swept empty, shops are closed, and manufacturing is reduced or at a complete standstill. But what happens to safety-related systems, e.g. in the pharmaceutical or food industry, which must not stand still and are designed in such a way that they cannot fail? How can the risk of breakdowns and downtimes be minimized? Or in the event of failure, how can the damage to people and the environment be limited or, in general, the operational sequence maintained?
Digitalization: curse or blessing?
When considering process engineering plants, one is repeatedly confronted with buzzwords such as «Industry 4.0», «digitalization», «digital transformation», «IoT», «smart manufacturing», etc. The topic is often discussed controversially and often it is about an either-or dichotomy: either man or the machine and the associated fears. No matter what name you give to digitalization, each term here has one thing in common: intelligently networking separate locations and processes in industrial production using modern information and communication technologies. Process automation is a small but important building block that needs attention. Data can only be consistently recorded, forwarded, and reproduced with robust and reliable measurement technology.
For some time already, topics including sensors, automation, and process control have been discussed in the process industry (PAT) with the aim of reducing downtimes and optimizing the use of resources. However, it is not just about the pure collection of data, but also about their meaningful interpretation and integration into the QM system. Only a consequent assessment and evaluation can lead to a significant increase in efficiency and optimization.
This represents a real opportunity to maintain production processes with reduced manpower in times of crisis. Relevant analyses are automatically and fully transferred to the process. This enables high availability and rapid intervention, as well as the assurance of high quality requirements for both process security and process optimization. In addition, online monitoring of all system components and preventive maintenance activities effectively counteracts a failure.
Digitally networked production plants
Even though digitalization is relatively well-established in the private sector under the catchphrase «smart home», in many production areas the topic is still very much in its infancy. In order to intelligently network different processes, high demands are made. Process analysis systems make a major contribution to the analysis of critical parameters. Forwarding the data to the control room is crucial for process control and optimization. In order to correspond to the state-of-the-art, process analysis systems must meet the following requirements:
Transparent communication / operational maintenance
Processes must be continuously monitored and plant safety guaranteed. Downtimes are associated with high expenditure and costs and therefore cannot be tolerated. In order to effectively minimize the risk of failures, device-specific diagnostic data must be continuously transmitted as part of the self-check, or failures must be prevented with the help of preventive maintenance activities. Ideally, the response must be quick, and faults remedied without having to shut down the system (even remotely).
If you consider how many years (or even decades) process plants are in operation, it is self-explanatory that extensions and optimizations must be possible within their lifetime. This includes both the implementation of state-of-the-art analyzers and the communication between the systems.
In order to prevent faults from endangering the entire system operation, redundancy concepts are generally used.
Practical example: Smart concepts for fermentation processes
Fermenters or bioreactors are used in a wide variety of industries to cultivate microorganisms or cells. Bacteria, yeasts, mammalian cells, or their components serve as important active ingredients in pharmaeuticals or as basic chemicals in the chemical industry. In addition, there are also degradation processes in wastewater treatment assisted by using bioreactors. Brewing kettles in beer production can also be considered as a kind of bioreactor. In order to meet the high requirements for a corresponding product yield and the maintenance of the ideal conditions for proper metabolism, critical parameters have to be checked closely, and often.
The conditions must be optimally adapted to those of the organism’s natural habitat. In addition to the pH value and temperature, this also includes the composition of the matrix, the turbidity, or the content of O2 and CO2. The creation of optimal environmental conditions is crucial for a successful cultivation of the organisms. The smallest deviations have devastating consequences for their survival, and can cause significant economic damage due to loss of product.
With the advent of smart technologies, online analysis systems and maintenance-free sensors have become indispensable to ensure the survival of the microorganisms. In this way, reliably measured values are delivered around the clock, and it is ensured that these are transferred directly to all common process control systems or integrated into existing QM systems.
Rather than manual offline measurement in a separate laboratory, the analysis can be done directly in the medium or be moved to an external measuring cell. Online analysis has an extra advantage compared to inline analysis. With this method, the sample stream is fed to the analysis system by suction with peristaltic pumps or bypass lines. Online analysis not only enables the possibility of 24/7 operation and thus a close control of the critical parameters, but also the combination of different analysis methods and the determination of further parameters. This means that several parameters as well as multiple measuring points can be monitored with one system.
The heart of the analysis systems is the intelligent sensor technology, whose robustness is crucial for the reliable generation of measured values.
pH measurement as a vital key parameter in bioreactors
Knowledge of the exact pH value is crucial for the product yield, especially in fermentation processes. The activity of the organism and its metabolism are directly dependent on the pH value. The ideal conditions for optimal cell growth and proper metabolism are within a limited pH tolerance range, which must be continuously monitored and adjusted with the help of highly accurate sensors.
However, the exact measurement of the pH value is subject to a number of chemical, physical, and mechanical influencing factors, which means that the determination with conventional inline sensors is often not an easy task. For example, compliance with hygiene measures is of critical importance in the pharmaceutical and food industries. Pipelines in the production are cleaned with solutions at elevated temperatures. Therefore, robust inline pH sensors are necessary to avoid detrimental effects (e.g., reduced accuracy, sensitivity, and lifespan).
Intelligent and maintenance-free pH electrodes
Glass electrodes are mostly used for pH measurement because they are still by far the most resistant, versatile, and reliable solution. However, in many cases changes due to aging processes or contamination in the diaphragm remain undetected. Glass breakage also poses a high risk because it may result in the entire production batch being discarded. For the pharmaceutical industry, the ProTrode 200 and ProTrode 300 sensors from Metrohm Process Analytics are the perfect solution to avoid these issues. They are equipped with a silver scavenger to avoid Ag ion contaminations from the process sample.
ProTrode 200 (left) and ProTrode 300 (right) sensors for pharmaceutical and biotechnology process environments.
Besides, these Swiss quality sensors offer type HT quality glass which enables stable readings and accurate measurements over a broad pH range with the ability to withstand the most challenging environments. In many process solutions, measurement with process sensors takes place directly in the medium, and sometimes calibration and maintenance can be a challenge. Our ProTrode pH sensors have been designed from the inside out to be able to perform calibration and maintenance in a safe area (e.g., laboratory) and all data can be easily transferred to the inline sensor without costly maintenance work and downtime.
On the other hand, online process analyzers are also a good solution for pH measurement. Here, the measurement is transferred from the process to an external measuring cell. This enables a long-lasting pH measurement to be achieved with an accuracy that is not possible with classic inline probes.
Metrohm Process Analytics has gathered decades of application know-how regarding both high quality sensors and process analysis. When pH measurement is carried out with online process analyzers, then calibration, adjustment, and cleaning can be carried out fully automatically. The system continuously monitors the condition of the electrode. Between measurements, the electrode is immersed in a membrane-friendly storage solution that avoids drying out, and at the same time prevents the hydration layer from swelling further as it does not contain alkali ions. The electrode is always ready for use and does not have to be removed from the process for maintenance work.
Maintenance and digitalization
In addition to the automatic monitoring of critical process parameters, transparent communication between the system and the analyzer also plays a decisive role in terms of maintenance measures. The collection of vital data from the analyzer to assess the state of the system is only one component. The continuous monitoring of relevant system components enables conclusions to be drawn about any necessary maintenance work. For example, routine checks on the condition of the electrodes (slope / zero point check, possibly automatic calibration) are carried out regularly during the analysis process. Based on the data, calibration and cleaning processes are performed fully automatically, which allow robust measurement even at measuring points that are difficult to access or in aggressive process media. This means that the operator is outside the danger zone, which contributes to increased safety.
The linking of production processes with digital technology holds a particularly large potential and contributes to the economic security of companies. In addition, the pressure is growing steadily for companies to face the demands of digitalization in production. As an example, in the area of fermentation processes, the survival of the microorganisms is ensured by closely monitoring relevant parameters. Intelligent systems increase the degree of automation and can make the process along the entire value chain more efficient.
Find out in the next installment how functional safety concepts help to act before a worst case scenario comes true where errors occur and systems fail. Check it out here!
Inline pH analysis made easy
High quality process measurements with the same sensor technology as the laboratory.
Post written by Dr. Kerstin Dreblow, Product Manager Wet Chemical Process Analyzers, Deutsche Metrohm Prozessanalytik (Germany).