Nitrogen gas use in Bottling industry as a counter pressure gas

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TITLE: USING NITROGEN GAS IN PLACE OF CARBON DIOXIDE GAS

AS A COUNTER PRESSURE IN BOTTLING INDUSTRY

FOR COST REDUCTION AND REDUCED ENVIRONMENTAL IMPACT

1. Executive Summary
2. Current Scenario – Carbon Dioxide gas use in beverage bottling plants
3. Concerns with Carbon Dioxide gas usage in counter pressure process
4. Global consideration of Nitrogen gas as CO2 replacement
5. Benefits of nitrogen over CO2 as counter pressure gas
6. Technical Impact Analysis Nitrogen gas versus CO2 cylinders
7. Cost impact analysis
   

   1. Executive Summary

Beverage bottlers processing carbonated beverages extensively use CO₂ most obviously for carbonation process, but also in a process for maintaining filler bowl counter pressure during the bottling process. Use of CO₂ in this process contributes not only to greenhouse gases, but also is a significant cost to the bottler. Nitrogen has already been proven in different parts of the world as an excellent replacement to CO₂ in the bottling process and can be done in a significantly cheaper way. This paper presents the findings and summarizes the benefits a bottler may enjoy in switching from CO₂ to Nitrogen.

2. Current Scenario – Carbon Dioxide gas use in beverage bottling plants

Beverage bottling plants use carbon dioxide gas in two distinct operations. CO₂ gas lines are different for both the processes:

a) Carbonation Process In this process CO₂ is mixed with beverages. This dissolved carbon dioxide creates carbonic acid, which adds a pleasantly acidic flavor and an interesting mouth feel.

b) Filler Bowl Counter Pressure Process – In the process of beverage carbonation, CO₂ is absorbed under pressure. The CO₂ will remain absorbed in solution while it is kept under pressure.

The pressure required to maintain CO₂ in the beverage depends on the content required in the beverage and the temperature. Higher CO₂ contents require higher pressure at a given temperature and conversely, lower temperatures for a given content require lower pressures.

The filler bowl must, therefore, be kept under the appropriate pressure during the filling process by use of an inert gas. This inert gas itself, typically CO₂, does not get further absorbed in the already carbonated beverage solution.

3. Concerns with Carbon Dioxide gas usage in counter pressure process

In the filling bowl counter pressure operation to establish an equilibrium pressure inside the bottle, carbon dioxide gas is used and released into the atmosphere on a continuous basis.

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It is commonly known and understood that CO₂ is a harmful greenhouse gas and it’s increasing concentration in the environment, a major environmental concern. CO₂ contributes to extra heat trap in the atmosphere and thereby contributing to Global Warming.

4. Global consideration of Nitrogen gas as CO₂ replacement

According to prior submissions of projects to United Nations Framework Convention on Climate Change, (UNFCCC)[1], under program of Clean Development Mechanism (CDM), a project to replace the Carbon Dioxide Gas with Nitrogen Gas in only filling operation for filler bowl counter pressure of a beverage bottling plant in Philippines was approved and implemented.

In the afore-mentioned project nitrogen gas replaced the carbon dioxide gas i.e. used in filling operation as a counter pressure. For the other use of carbon dioxide gas such as for mixing the Carbonated Soft Drinks (CSD) line, it was not included & not affected.

5. Benefits of nitrogen over CO₂ as counter pressure gas

There are several technical and commercial benefits of using Nitrogen as a counter pressure gas instead of CO₂:

• Due to CO₂ being discharged into atmosphere continuously in the counter pressure process, use of nitrogen in place of CO₂ helps in reduction of greenhouse gas emissions.
• Nitrogen and CO₂ are both inert, and neither gas is absorbed into the carbonated beverage. Hence use of nitrogen in place of CO₂ is acceptable without any technical concerns.
• Nitrogen gas is easily produced at premises by using an on-site gas generator, such as those offered by MVS Engineering. Nitrogen gas generators work on the principle of separating and concentrating 78% nitrogen present in atmosphere to a higher purity level of 99% and above. Hence, nitrogen is very simple to produce and can be produced on-demand basis as the generator takes only 1-2 minutes to start production.
• CO₂ is purchased from market in cylinders and the cost of each cylinder varies from location to location and also quite high. Nitrogen production using an on-site generator is extremely low and is only the cost of power required by air compressor. Please refer to cost implication section of this article for detailed cost benefits.
• Installing nitrogen generator and producing the gas on-demand, you will avoid the cost and hassles of always ordering and delivering CO₂ cylinders by trucks.
• By replacing with nitrogen, CO₂ cylinder handling within premises is completely avoided. This is an OHSA (health and safety) benefit, as bulk cylinder handling is a human task and prone to errors and failures.
• Storing large amount of CO₂ in cylinders is a concern as large quantities of CO₂ may leak and create asphyxiation hazard. Nitrogen is produced on-demand and large quantities of nitrogen are typically not stored or if stored, the storage tank is installed outdoors, where leak of nitrogen will easily dissipate without creating asphyxiation hazard.
• Due to reduction in CO₂ emissions, another important benefit beverage industries can get are of Certified Emission Reduction (CER) credits. These CERs can be traded and sold and used by industrialized countries to meet a part of their emission reduction targets under Kyoto protocol.
• Beverage bottlers interested in nitrogen generator for CO₂ replacement may consider applying for Adaptation Fund. It is an international fund that finances projects and programs aimed at helping developing countries to adopt to the harmful effects of climate change. It is setup under the Kyoto protocol of the UNFCCC.

• 6. Technical Impact Analysis ? Nitrogen gas versus CO₂ cylinders

   

  1. We present below an un-biased comparison of producing nitrogen gas on-site as compared to using CO2 in cylinders purchased from the market.

2. We must also calculate the emission reduction due to avoidance of CO₂ use and present a case below on basis of certain data presented earlier.

7. Cost impact analysis

In order to understand how beverage bottlers may benefit from use of Nitrogen in place of carbon dioxide as a counter pressure gas, we must consider the cost of CO2 in cylinders and then compare it against the cost of nitrogen production by an onsite nitrogen generator.

a) Cost of Carbon Dioxide Gas purchased by Cylinders

Present rate of CO₂ gas cylinders in Indian market = Rs 50 INR/Kg of CO₂ gas.

1 Kg of CO₂ gas = 0.5058 Nm³ of CO₂ gas, or

1 Nm³ of CO₂ gas = 1.97 Kg of CO₂ gas

Hence, the cost of 1 Nm³ of CO₂ gas in cylinder can be calculated as

1 Nm³ CO₂ = 1.97 Kg of CO₂ gas x Rs 50 INR/kg CO₂.

1 Nm³ CO₂= Rs. 98.85 /Nm³ of CO₂

b) Cost of Nitrogen gas produced onsite using gas generator

To produce nitrogen gas from an onsite gas generator requires electricity to operate the air compressor and this is the primary variable cost of operation.

For producing 1 Nm³ Nitrogen gas we require only 0.5 KWH electricity power.

If we consider industrial electricity rate of around Rs. 7 / kWh, the production cost of nitrogen by generator can be estimated as Rs 3.50 INR/Nm³