Use of CO2 Flow Meter for Carbonation

October 26, 2021 Mickaël Soobaroyen

Are you familiar with carbonation? Perhaps not all of you know this word and yet you see the results of carbonation almost every day; it provides the bubbles in your cola or mineral water :) In this process flow meters play an important role. The flow meter measures and controls the amount of carbon dioxide (CO2) to be dissolved in the carbonated drinks during the carbonation process.

Guillaume WURGER, company manager of Actemium Strasbourg Plant Solutions, explained me all about their carbonator as this is one of their flagship activities and how they use flow meters in the process.

flow meters for carbonation process

How does carbonation work?

Carbonation is a chemical process, the saturation of a liquid with carbon dioxide. This thermodynamic phenomenon can be explained by Henry's law. This essential law of physics stipulates that at a constant temperature, the quantity of gas dissolved in a liquid is proportional to the pressure exerted by this gas on the liquid.
In case of carbonation, the goal is to obtain a certain concentration of CO2 in a liquid. It is essential to consider the specific pressure and temperature conditions which must be respected, depending on the type of product. This balance must be perfectly controlled throughout the process and this is the point where flow instruments come into the picture.

Carbonator for soft drinks

Actemium Strasbourg Plant Solutions is a VINCI Energies company and specialises in process solutions, like mixing skids, gas injection systems and pasteurisation. Carbonation is one their core activities.

carbonation setup

“Ten years ago, our taste for innovation led us to develop a carbonator which we patented and which enables our customers to produce carbonated drinks. We have taken up the user's problem with traditional solutions: CO2 injection efficiency, a bulky system and energy-consuming process. With this equipment, the challenge is to:

  • optimise the process regarding volume compensation in the liquid tanks
  • to increase the quality of the finished products, the carbonated beverage
  • and to save time, e.g. for tank cleaning, total dissolution of the CO2, etc.
One of the innovative aspects of the Actemium Strasbourg Plant Solutions carbonator is to inject the CO2 in line to dissolve it in the beverage. By adjusting the pressure balance, the dissolution of the CO2 in the liquid will be encouraged. When the values exceed the equilibrium, we advise ‘grassing’, in other words dissolution of the CO2. When the values are below equilibrium, we advise ‘degassing’, so we have a formation of CO2 bubbles which are led to escape from the product. When the product is a sweet one, then foam is obtained.

The dissolution of the CO2 in mineral water - or other soft drinks – ensures the carbonic acid to appear, which gives the beverage a ‘fizz’. The pressure and temperature conditions in the process are essential to regulate the amount of gas to be dissolved.
In our case, we work in line with high pressure conditions for a controlled period of time, which guarantees that 100% of the injected gas is dissolved. A perfect yield, as we only inject the quantity of gas we need! To precisely control the CO2 gas injection, we use Bronkhorst GAS mass flow controllers, from the IN-FLOW High-FLOW range.

What is the role of the Flow Controllers?

To solve the problem of the inconvenient and consuming CO2 tanks you need a solution capable to inject gas in-line and continuously. But without a tank, you have no buffer volume available: which means your gas injection system must be able to deal with variations in the liquid flow line, changes in flow rates and start/stop functions. These are challenges you must face in a continuous process like this!

To achieve this, we created a recirculation loop in our system. The flow will be controlled by the system's internal pump and the recirculation depends on the needs of the downstream bottling machine. This way we do not use a tank, so we can get as close as possible to the bottling machine. The Bronkhorst IN-FLOW High FLOW mass flow controllers are ideally suited for this application. Their technology based on a thermal principle makes them insensitive to pressure variations and they regulate the flow rate with the help of the instrument's internal PID loop. The low response time also allows them to compensate for process variations, without impacting on the accuracy of the amount of CO2 added into the beverage.

IN-FLOW mass flow meter for carbonation
IN-FLOW mass flow meter for carbonation

In the traditional system, the flow sensor, control loop in the PLC and control valve were all separately installed. The Bronkhorst solutions provides us a 3-in-1 solution with a very low reaction time, a higher control resolution than the PLCs on the market and with a compact electric actuator. Besides that, the flow instruments are equipped with industrial communication protocols that allow access to the control parameters of the devices.
Actemium uses the Profinet network, which has improved the speed of transmission, the accuracy of the signals and the fact that it is possible to monitor the parameters present in the instrument. With these features, Actemium ensures that it supplies quality equipment to its customers and meets their needs.

Full control on what you inject, for a perfect quality of your carbonated drink.

VINCI Energies & Actemium

Their mission: help customers improve their competitive advantage and industrial performance. Actemium is a powerful worldwide network of 400 Business Units located in 41 countries across the world; it is 100% dedicated to industrial process. The brand network is a multi-disciplinary network, able to offer customized multi-technical, multi-site or multi-country services. Actemium’s 22,000 experts work to deliver a range of safe and sustainable solutions & services across the entire industrial life cycle. In its day-to-day operations, Actemium builds on its powerful networking system expertise in each process in order to provide turnkey solutions.

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