In the fast-paced world of industrial manufacturing, managers face a multitude of critical decisions daily. Among the most important is how best to monitor and control production processes through laboratory-based (offline) analysis or by integrating online/inline (process) analytical systems directly into the production line.
This decision can have a significant impact on product quality, operational efficiency, safety, and ultimately, profitability. While there’s no one-size-fits-all answer, understanding the key factors behind each approach can empower decision-makers to select the best solution for their specific environment.
Traceability, communication, and control
In modern facilities, seamless communication between analysis systems and control rooms is crucial. Online and inline process analysers, such as those offered by Metrohm Process Analytics, are designed to deliver real-time data directly to Distributed Control Systems (DCS), Programmable Logic Controllers (PLC), or Supervisory Control and Data Acquisition (SCADA) systems. This real-time feedback allows for instant corrective actions, optimising dosing, minimising waste, and maintaining consistent quality.
A key element in this setup is Metrohm’s fully integrated IMPACT software, which stores encrypted data, triggers alerts when thresholds are breached, and ensures traceable, tamper-proof results. It also supports conditional logic, enabling analysers to automatically adjust sampling rates based on process stability. When conditions are steady, the system conserves resources by reducing analysis frequency. If fluctuations are detected, it ramps up measurements to provide granular data for prompt intervention.
Conversely, laboratory instruments typically operate in isolation from plant control systems. While they offer the same analytical accuracy, integrating their data with control room infrastructure requires additional software, effort, and stakeholder approval. This can lead to increased cost and complexity though for simple, stable processes with low analysis frequency, laboratory testing may still be the most practical option.
Frequency of analysis: The value of real-time data
One of the most decisive factors in selecting an analytical approach is the required frequency of testing. In scenarios where rapid response is essential – such as when multiple measurements are needed per shift – online/inline systems provide significant benefits. They reduce the likelihood of out-of-specification products, unscheduled downtimes, or costly overcorrections.
By continuously capturing data, process analysers provide a highly detailed picture of the current production conditions. This reduces human error and helps avoid reprocessing and wastage, all while maximising uptime.
On the other hand, for applications where parameters only need checking once per shift laboratory analysis remains a viable choice. However, decision-makers should be aware of potential pitfalls. Time delays between sampling and analysis mean results may not reflect current process conditions, especially for sensitive parameters like pH, temperature, or moisture. This can lead to inaccurate adjustments or excessive chemical dosing.
Nevertheless, laboratory analysis allows for more extensive and thorough examination of samples. With properly trained staff and strict sampling protocols, the risk of errors can be minimised, making it a useful tool for verifying trends or supporting quality control in less time-sensitive applications.
Safety first: protecting personnel and processes
In industries handling hazardous or explosive substances, safety is paramount. Manual sampling and laboratory transport pose potential risks to personnel. In such cases, online/inline analysers offer a safer alternative, reducing human interaction with dangerous materials.
Metrohm’s explosion-proof process analysers are specifically engineered for deployment in hazardous environments, allowing continuous monitoring without exposing workers to harm. By automating sampling and measurement, these systems minimise contact with chemicals and enhance safety while maintaining high analytical accuracy.
Location and accessibility
The physical layout of a production site also plays a role in determining the most appropriate analysis method. For instance, identity verification of incoming raw materials can now be carried out with handheld devices such as the Metrohm Instant Raman Analyser (MIRA). These tools allow fast, non-destructive testing at goods-inward checkpoints without the need to open containers or disrupt the production flow.
Where multiple sampling points across a facility require frequent monitoring, process analysers offer a cost-effective solution. Thanks to platforms like the 2060 from Metrohm, analysis cabinets can be installed close to sample points, while human interfaces are positioned elsewhere, freeing up valuable space and simplifying access.
For compact environments or where space constraints are a concern, the use of inline sensors eliminates the need for separate sampling setups. These sensors are installed directly in pipes or reactors, sending real-time signals back to analysers or transmitters without requiring large footprints.
Implementation: flexibility and integration
Adopting an online or inline system doesn’t mean sacrificing flexibility. With modular platforms such as the 2060, Metrohm offers scalable solutions that adapt to various production layouts. From long-distance sampling using low-dispersion optical fibres to multi-point analysis from a single cabinet, there are numerous options available to meet the unique demands of different industrial sectors.
Where implementation is not feasible due to infrastructure limitations or budgetary constraints, laboratory systems still have a place. They offer broader flexibility in setup and can be deployed in stages as part of a wider process improvement strategy.
The verdict: it’s not either/or
Ultimately, there’s no clear-cut winner between online/inline and offline laboratory analysis. Each has its place depending on the specific needs of the process, the plant layout, safety requirements, and the desired return on investment.
The key is to assess your production environment holistically. For real-time control, improved safety, and long-term cost savings, process analysers are the preferred choice. For infrequent testing, complex sample prep, or where infrastructure limits installation, laboratory instruments continue to offer value.
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