Analyzing CO2 Purity with the MAX-Bev CO2 Purity Monitoring System

insights from industryRuben van der WulpBusiness Development Representative - MAX-iRThermo Fisher Scientific

In this interview, AZoMaterials speaks with Ruben van der Wulp, Business Development Representative for the Thermo Scientific MAX-iR gas solutions team, about the use of Thermo Scientific’s Max-Bev FTIR analyzer in the analysis of carbon dioxide (CO₂) purity in the beverage industry.

Video Credit: Thermo Fisher Scientific

Could you introduce yourself and your role at Thermo Scientific?

My name is Ruben van der Wulp, and I am a Business Development Representative for the Thermo Scientific MAX-iR gas solutions team. I hold a Master of Science Degree in Biomedical Engineering from the Eindhoven University of Technology and specialize in Fourier transform infrared (FTIR), near-infrared (NIR), and Raman analysis.

I joined Thermo Fisher Scientific back in 2020, and since 2023, my main focus has been FTIR gas analysis and associated business development for Europe, the Middle East, and Africa. My colleagues and I investigate new market opportunities and determine what is needed in terms of technology and regulation.

Real-time analysis of beverage-grade CO₂ purity for quality assurance

Why is real-time analysis of beverage-grade CO₂ purity important for quality assurance?

The analysis of CO₂ purity is crucial for both safety and flavor. For example, from a safety perspective, identifying carcinogenic components like benzene is imperative. Acetaldehyde adversely affects the taste and, therefore, quality of a drink, making real-time analysis imperative for upholding high standards.

How is CO₂ produced for the beverage industry?

Various sources can be utilized to produce CO₂ for the beverage industry. The impurities introduced into the bulk CO₂ vary depending on the method of production.

Different processes include combustion (where fuel reacts with oxygen to produce CO₂ and water as products), fermentation (where yeast or bacteria metabolize sugar, converting it into alcohol or CO₂), and ammonia and hydrogen production (where CO₂ is produced as a byproduct of the methane steam-reforming process).

The specific impurities introduced  stream, such as acetaldehyde, air, benzene, methanol, sulfur components, or hydrocarbons, depend on the chosen source of CO₂ production). To ensure product quality and safety, instrumentation must be capable of monitoring many different impurities simultaneously.

How do ISBT and EIGA standards guide the monitoring of trace impurities in different CO₂ production methods?

The International Society of Beverage Technologists (ISBT) and the European Industrial Gases Association (EIGA) set standards for CO2 product quality, including which trace impurities must monitored and concentration limits.

The two standards are similar, but the EIGA standard identifies additional components that should be monitored depending on the production method. For example, CO2 produced by fermentation must be checked for halocarbons, hydrogen cyanide, and ketones, in addition to the standard set of impurities.

What challenges arise when assessing CO₂ purity?

There is a long list of impurities that need to be monitored. Challenges involve simultaneously analyzing a diverse list of impurities, which, of course, vary by CO₂ source. Instrumentation must be insensitive to cross-interferences to avoid false results.

Speed is also crucial, as time is money. In large CO₂ plants, where you are monitoring different streams of CO₂, fast analysis is necessary so that operation procedures can continue. Thus, analysis of a gas stream or a storage tank of CO₂ needs to be relatively quick.

What advantages does FTIR offer for CO₂ analysis?

Fourier tranform infrared (FTIR) spectroscopy is a reliable technique that operates 24/7 with minimal downtime and provides accurate and reproducible results.

The advantage of FTIR over other techniques such as mass spectrometry is that it is factory calibrated, and calibrations are stable throughout the system's lifetime. FTIR is also a relatively fast analytical technique, enabling real-time monitoring of trace impurities. Plus, FTIR has a very wide dynamic range, meaning it can measure trace impurities at low part-per-billion (ppb) levels as well as absolute CO₂ purity at 99.9%. This eliminates the need for wet chemistry techniques to assess CO₂ purity.

FTIR is the heart of the Thermo Scientific MAX-Bev CO2 Purity Monitoring System.

What are the technical and commercial benefits of the Thermo Scientific MAX-Bev CO₂ Purity Monitoring System?

With the MAX-Bev, analysis can be done at the touch of a button via automated software workflows, or operators can schedule analysis of up to 10 streams. Results can be accessed anytime from the historical reporting database. The certificates of analysis can also be automatically generated and printed by the operator.

Additionally, our MAX-Bev solution offers the flexibility to adapt your gas list depending on the CO₂ source or standard. This means you can run different methods simultaneously within the same system, ensuring certification of these different sources according to the ISBT or EIGA standard.

In terms of technical benefits, the MAX-Bev system ensures CO₂ verification, prioritizing consumer safety and brand reputation for bottlers. The system operates solely with FTIR—no other analytical technique is used. This reduces maintenance and downtime (which only occurs when preventative maintenance is being done to the system), ensuring year-round reliability.

Regarding commercial benefits, the lead time of this integrated solution is less than 24 weeks. If you plan on building a CO₂ plant or undertaking short-term carbon-capturing projects, our lead times will not cause delays. Our suppliers trust the MAX-Bev because of the reliability and efficiency of the system.

What is the workflow of the Thermo Scientific MAX-Bev CO₂ Purity Monitoring System?

The MAX-Bev can measure gases. If you are monitoring the CO₂ in the gas form, you can bring it directly to the system. Liquid CO₂ can also be stored in a truck, railcar station, or a bulk storage tank.

A vaporization unit vaporizes the CO₂. It is then transported through plumbing or heater transfer lines to the MAX-Bev. The flow is controlled by the MAX-Bev’s internal Mass Flow Controller.

The gas arrives at the system, which follows a two-step mechanism. Step one is to measure the absolute CO₂ purity and all the trace contaminants (excluding the sulfur components). Step two is to measure the total sulfur by oxidizing all the sulfur components and then quantifying that with the MAX-IR. This two-step process takes about 10 minutes per stream.

The system includes a multiplexer with ten channels for simultaneous monitoring. For instance, if you are going to monitor six different channels, you can monitor them all within one hour and the results will be automatically reported.

This report includes the concentration data and the pass/fail results. The operator can then print the certificate of analysis, which can be used as proof  to their end customers.

How does the Thermo Scientific MAX-Bev CO₂ Purity Monitoring System manage cross-interferences between components with similar chemical structures?

The system manages cross-interferences, such as acetaldehyde and acetone, by analyzing peaks in the FTIR absorbance spectra. To elucidate, the functional groups of the acetaldehyde and acetone will absorb in a specific way and react with the infrared light—resulting in unique peaks on the FTIR absorbance spectra.

For acetaldehyde and acetone, these peaks overlap. However, with the software, hardware integration, and software that we use, we can differentiate between those peaks.

The system was tested with a mix of acetone and acetaldehyde, with a blend intolerance of approximately 5 %, and demonstrated the ability to selectively choose and quantify peaks to avoid false data.

How does the Thermo Scientific MAX-Bev CO₂ Purity Monitoring System manage unknown components in the gas stream?

While pre-calibrated for expected components, our system employs a peak matching tool to identify and qualify unknown components in the FTIR spectrum. Utilizing the NIST and EPA library database, this tool enables the qualification of unknowns, which can then be added to your method.

This offers a lot of flexibility, but it is the reliability and sensitivity of the system that is needed to certify your CO₂ towards the ISBT and EIGA standards.

How is the absolute CO₂ purity measured in the Thermo Scientific MAX-Bev CO₂ Purity Monitoring System, and what studies were conducted to validate its accuracy?

The absolute CO₂ purity is measured using a research-grade CO₂ cylinder. When our MAX-Bev is being produced in our factory, before we ship it, we always do a repeatability study in the laboratory. This involves measuring the concentration of the absolute CO₂ purity using 12 replicates. The results demonstrate a percentage of error of plus or minus 0.02 % and a low standard deviation. This highlights the sensitivity and reliability of our measurement system.

In addition to a laboratory study, a field study was conducted at a customer’s site with a large storage tank. The absolute CO₂ was assessed over two weeks, showing high sensitivity and staying well within the specified limits of plus or minus 0.02 %, even over a longer period.

Real-time analysis of beverage-grade CO₂ purity for quality assurance

What are the benefits of choosing FTIR for total sulfur measurements in the Thermo Scientific MAX-Bev CO₂ Purity Monitoring System?

Moving on to step two of the analysis, which involves measuring total sulfur, there are various options available. For instance, total sulfur can be measured by the MAX-Bev by FTIR only. The advantages of this approach include factory calibration, ensuring stable sulfur dioxide (SO₂) calibration throughout the lifespan of the instrument.

The detection limit is below 30 ppb, well within the 100 ppb limits set by the ISBT and EIGA. Additionally, there are no scheduled replacement parts, and only annual preventive maintenance is needed, resulting in a system uptime of approximately 99.7 %.

Ultraviolet (UV) fluorescence is another method we have explored. However, this requires routine recalibration and frequent spanning as the UV lamp degrades. It does offer better sensitivity; however, because of the maintenance cost, the cost of ownership, and the downtime, we prefer to work with the FTIR.

So, that is a bit of a trade-off. Do you want to have a system that runs continuously and provides you with the results that you need? Or do you want to have a slightly more sensitive system that costs more and has a higher downtime? With the FTIR, you will be able to measure all year round, meaning that you can certify your CO₂ by ISBT or EIGA standards.

Could you provide insights into the total sulfur accuracy and linearity study conducted for the Thermo Scientific MAX-Bev CO₂ Purity Monitoring System?

We performed a random measurement by introducing different concentrations of SO₂ into the system, ranging from 50 ppb to 250 ppb. The actual measured ppb value sat in the middle of this range, demonstrating an error percentage well within plus or minus 10 %.

When focusing on the specific concentration of approximately 100 ppb (according to ISBT and EIGA) the percentage of error ranged from 0 % to 6 % or 7 %. We also tested the linearity of total sulfur, revealing an R² value of 0.9952, indicating a highly reliable measurement for your sulfur components.

How is the quality assurance and quality control plan structured for this system?

I want to specifically state again that the system is always calibrated, so from the moment that you get it, the system is calibrated and will be calibrated for the lifetime of the system. However, we need to periodically validate the results using certified gases to ensure the defensibility of the results.

It is important to note that these gases are not used for calibration but for verification or validation. These gases can be used for zeroing the FTIR and collecting new backgrounds by ultra-high purity nitrogen.

They are also employed to validate impurities, comprising a blend of five ppm COS, 10 ppm benzene, and 75 ppm of propane in nitrogen balance. This mixture is used to validate both the FTIR accuracy and the sulfur conversion efficiency every month.

Additionally, for absolute CO₂ purity, validation is conducted using research-grade CO₂, which can also be done monthly (depending on the results).

Could you please summarize how the Thermo Scientific MAX-Bev CO₂ Purity Monitoring System can be used in the analysis of CO₂ purity?

If you seek real-time analysis of CO₂ purity and a solution that delivers the results you need, FTIR spectroscopy allows for the real-time analysis of absolute CO₂ purity and all the normal trace impurities, including the total sulfur content specified by ISBT and EIGA.

This is achieved using a single FTIR or gas analyzer, simplifying the overall measurements, reducing maintenance costs, and enhancing overall efficiency. So, as we say with Thermo Fisher Scientific, "Don’t miss out, MAX out".

About Ruben van der Wulp

Ruben van der Wulp is the Business Development Representative for the Thermo Scientific MAX-iR Gas Solutions within the company Thermo Fisher Scientific for the EMEA region. With a MSc degree in Biomedical Engineering obtained at the Eindhoven University of Technology, he joined Thermo Fisher Scientific in 2020. Ruben is an expert in FTIR, NIR & Raman analysis.

Since 2023, his focus is on FTIR gas analysis and associated business development for the EMEA region. He investigates new market opportunities with his colleagues and determines what is needed in terms of technology and regulation.

This information has been sourced, reviewed and adapted from materials provided by Thermo Fisher Scientific – Environmental and Process Monitoring Instruments.

For more information on this source, please visit Thermo Fisher Scientific – Environmental and Process Monitoring Instruments.