"Safety comes first"
Specially developed devices are used to retrieve direct samples from production, analyze them, and reset the process control system based on the results. We spoke to Werner Pettau, the Head of Analytical Services at BYK, about modern online analysis.
Mr. Pettau, what exactly is online analysis?
In conventional analysis, for example to control a chemical reaction, we take samples and analyze them in the quality control laboratory for certain defined specification values. In online analysis, this work is done by a probe in the reaction vessel or the substance is pumped to a measuring station via a bypass. This allows us to measure the value any number of times and in real time.
Are these two methods capable of measuring exactly the same values that used to be determined in the lab?
It isn't possible directly, but by way of calibration. This means that online measurements and the conventional methods are performed parallel to one another. Humans often cannot recognize the correlation between the results of online measurements and the lab data. The calculation can only be done with highly complex computer programs, which require data from many different measurements to calculate a correlation.
That sounds quite complicated. Is that worth it?
Yes, because the conventional measurement is no longer necessary once the system is calibrated. This saves considerable work in the quality control laboratory.
You were talking about increases in efficiency, but does this modern method also have advantages for the environment and safety?
Oh, absolutely. For example, we avoid a lot of waste and energy consumption. Every sample during the reaction requires filling a glass vial with e.g., 60 milliliters and sending it to the lab for testing. After the analysis, the contents and the reagents are thrown out. Many reactions require as many as ten samples or more. In addition, it is easier to take the measurements in real time. This in part leads to shorter reaction times, which naturally saves energy.
And what about advantages for safety?
I see enormous advantages with the so-called exothermic reactions, which are reactions that involve the release of heat. These reactions can easily get out of control when too much energy is released in a short time. Cooling and precisely dosed raw materials can prevent this from happening. It is essential that there never is too much raw material that has not been converted. Online analysis checks precisely that, in real time and at any frequency. This increases safety.
Where is online analysis used?
In addition to incoming raw materials, we have started to control a few reactions in production with the so-called near-infrared method. This primarily pertains to quality control. Our process technicians are working to transfer new polymerization techniques to production scale. They are currently developing three different online analysis processes. Safety definitely comes first.
Which three procedures are these?
We are testing near-infrared, Fourier transformation infrared spectroscopy and ultrasound. All of these methods require the complex computing process I mentioned earlier.
Which method is the most promising?
Every method has its advantages and disadvantages. Ultrasound has a certain edge because the method is quite robust and relatively affor dable. However, the calibration requires highly qualified specialists.
Which of the four ALTANA Divisions could use this method?
It could actually be useful in all Divisions. I am thinking for example about increasing the safety of exothermic reactions. Such a reaction got out of control at a site in India. I see a lot of po tential for improvement. In the future, we plan to exchange information at our new analytical services meetings within ALTANA to learn from one another.