Gas Measurement Instruments - GMI

Monitoring Gases in the Drinks Industry

Introduction

Gas detection is required widely in the Drinks Industry for sanitising gases, Carbon Dioxide and refrigerant gases such as Ammonia or Freons. These gases are found in brewing, distilleries, juice producing as well as the soft drink and water bottling plants.

Many of these plants have not been concerned about gas detection as Carbon Dioxide is non-toxic and was considered harmless by many. This situation has changed over recent years and the requirements of DSEAR legislation (see separate Application Note for details) demands that all of these plants are now required to monitor Hazardous gases.

Additionally, F-Gas regulations that cover the use of Freons in refrigeration systems have led many companies in the Drinks Industry to use Ammonia as the refrigerant gas.

Application

Sanitising gases such as Chlorine, stored in cylinders, is often used to kill bacteria in vessels used in the production of beverages. Alternatives such as Chlorine Dioxide or Ozone are sometimes used.

Fermentation processes produce CO2 as a Bi-product and this occurs in both breweries and distilleries.

CO2 is used extensively in both soft drinks manufacture and bottling of beer to create the ‘fizz’ in the bottled or canned drink. This CO2 is often stored in bulk containers and used in high volumes on the automated bottling lines. Nitrogen is also used on occasions particularly where “smooth” or Guinness type beers are produced.

Many drink plants use extensive refrigeration and have large plant rooms containing Ammonia or Freons. Ammonia requires to be detected for personnel protection and for explosive risks Freons are being phased out, however, they are also required to be monitored in order to comply with the F-Gas regulations (please see separate application note). Distilleries are often required to monitor for the presence of flammable vapours, typically Ethanol, which is the primary constituent of alcoholic drinks.

Problem

There are at least four different problems that result from the applications detailed.

1. Firstly, the protection of personnel on site. Employees and visitors to a site that is using Ammonia as a refrigerant must be protected from its effects on health and safety grounds. Both portable and fixed instruments, or a mixture of both, can be used depending on site conditions. Alarms must be set at the Threshold Limit Value of the regional regulation. U.K. values would normally be LTEL 25ppm and STEL 35ppm.

   Additionally, Ammonia will taint any open drink that is stored either in cold stores or chillers causing large losses of product. This is now less likely due to Glycol or liquid CO2 being used as the coolant in modern systems and that the Ammonia plant is now kept away from the process area. However, if Ammonia can reach the process areas, low level Ammonia detection is essential to prevent the large financial losses that can result from leakage, no matter how small.

   The plant room is always subject to small leaks with moving equipment, valves and joints, so a background of Ammonia can be expected. The detectors used in these areas should therefore be capable of working in a constant background and the controller should be capable of controlling the ventilation. The detectors here will be capable of reading much higher vallues than just the TLV as high concentrations are a real possibility in this application. These plant rooms can vary from a small room requiring 1-4 points to a very large area with many more points required.

   As Ammonia is flammable, albeit difficult to set alight and only at high concentrations (15.4% v/v), it should still be monitored for explosion risk in any area where these levels could be possible. This risk should always be considered where large quantities of Ammonia are stored or compressed. The alarm point is generally set at 1% v/v at which point non-essential electrical systems are shut down.

   Please note that although Ammonia is lighter than air and should rise to the ceiling, this will only occur if the gas is at the same temperature as the surrounding atmosphere. With refrigeration gas this may not be true, so gas temperature at a leak point should be considered.

2. Secondly, CO2 is an asphyxiate and can cause drowsiness and headaches and therefore must be monitored. Typically, alarm levels are set at 0.5% v/v and 1.5% v/v. Sensors should always be placed as close to ground level as possible where CO2 will build up in the event of a leak. CO2 can be considered to act like water in its flow characteristics and this should be taken into consideration when placing / installing the sensors.

3. Thirdly, sanitising gases are considered to be extremely toxic with Chlorine and Chlorine Dioxide requiring measurement at sub P.P.M. (Parts Per Million) levels. Alarms for Chlorine are typically set to 0.5 PPM. Ozone is sometimes used and is typically generated on site. This requires detection in the low PPM range with alarm points set at 0.2 ppm.

4. Finally the detection of flammable vapours, mainly Ethanol, can be carried out using flammable sensors either catalytic type of Infrared. These would normally be installed / placed close to the ground as again this vapour acts very similar to water and will pool at the same places. Alarms for these sensors would normally be set to 10% LEL with a second alarm at 20% LEL.

Solution

GMI have a wide range of products specifically designed to meet and exceed all requirements of gas detection in the Drinks Industry. These systems have been designed to meet the vast range of different applications. The Active-8 and Active-80 range of control systems can be fitted with various types of Ammonia sensors dependent on range of detection required. An additional benefit is that they can also accommodate other sensors if required, e.g., CO2, Cl2, Freons, Flammable gases, etc., therefore, one system can satisfy all applications likely to be found in the drinks Industry.

In addition to these discreet sensor systems, GMI have a range of sampling systems designed to meet the unique challenges of different applications, however, similar to the Active-8 and Active-80 these can also be fitted with a range of sensors for other gases. The larger of these systems (Seafarer) it is capable of handling up to four gas sensors (flammable, PPM Ammonia, Freons, CO2 depending on application). This system is capable of drawing samples from up to 48 sample points and by using a fast flow manifold, cycle times are kept to a minimum.

The sample system will alert the operator if any of the pre-set alarm points are exceeded. The alphanumeric display clearly defines the nature and location of the problem enabling corrective action to be taken as quickly as possible. The system auto-senses if a sample line becomes blocked and will try to clear it by using the optional blow back system if fitted, otherwise it triggers an alarm.

GMI are more than happy to discuss your particular requirement for detection and will be able to propose the best system for your needs. This service is provided free of charge and without any obligation, so please call GMI +44 (0) 141 812 3211 and ask for Fixed Systems Applications Team or alternatively, e-mail This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

As an ISO 9001 approved company, GMI Ltd’s quality assurance programmes demand the continuous assessment and improvement of all GMI products. Information in this article could thus change without notification and does not constitute a product specification.

Please contact GMI or their representative if you require more details.

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