Do You Really Know Your Gas Consumption and Cost? – Part III (Nitrogen Cylinders)

In continuation of our previous blog series, which includes the blogs “Do We Really Know Our Gas Consumption and Cost? – Part I and Do You Really Know Your Gas Consumption and Cost? – Part II (Liquid Nitrogen) , in this article, we explore the technical and financial aspects of using Nitrogen Cylinders in industries.

In Part II , we highlighted the real costs of liquid nitrogen. This time, we’ll focus on Nitrogen Cylinders and specifically:

• Impact of the cylinder pressure on the overall actual consumption and procurement costs
• How Nitrogen Cylinders are actually used in industries
• The hidden costs and losses involved
• Why PSA Nitrogen Generators are a smarter and more cost-effective alternative

Case Study: Nitrogen Cylinders in Food & Beverage (MAP – Modified Atmosphere Packaging)

A client from the food and beverage industry approached us with a requirement for a PSA Nitrogen Plant. Their RFQ specified:

• Nitrogen Flow: 100 Nm³/hr
• Pressure at Usage Point: 6 Barg
• Purity Required: 99.999%

To validate these requirements, our team visited the facility and conducted a detailed nitrogen audit covering flow, pressure, purity, and actual usage. Since the client was already using Nitrogen Cylinders, we analysed their current consumption patterns, replenishment and billing cycles.  Below is a gist of the observations made by our team:

1. Nitrogen Purity Analysis
   • Recommended Nitrogen purity for MAP (EIGA Norms): 99.5-99.9%
   • Default UHP Nitrogen Cylinders Purity: 99.9997% (much higher than required)
   • Nitrogen Production Cost Difference in terms of Purity
     1. 99.999% nitrogen: ₹8.48/Nm³
     2. 99.90% nitrogen: ₹2.64/Nm³
   • Key Insights
     1. Nitrogen purity of 99.9% purity is widely acceptable in Food & Beverage MAP applications. Please read our blog titled Application of Nitrogen Gas in the Beverage Industry. PSA Nitrogen plants can generate Nitrogen as per the required purity level, thereby providing significant monetary savings on the production costs. The evidence above demonstrates that production costs are reduced by nearly 70%.
     2. There are also additional cost benefits that arise from lower administrative and operational costs. Selecting the right Nitrogen purity reduces the overall life cycle cost of a PSA plant.
        To read more about the cost implications of nitrogen purity, please read our blog titled, Understanding Nitrogen Purity in PSA Nitrogen Generators.
2. Nitrogen Flow Calculation Error
   To determine the nitrogen gas flow required for the application, we asked the customer to explain how they calculated the value mentioned in their RFQ (100 NM³/hr). They told us that they had reviewed their Nitrogen Cylinder Supplier’s invoice and divided the total nitrogen gas volume by the total working hours. While this method was theoretically acceptable, it overlooked one critical factor – the pressure of the Nitrogen Cylinder Supplied by the Vendor. The requirement was calculated based on the following data:

What’s wrong with this data? As visible from the above, the client divided the Nitrogen Cylinder volume directly by hours, ignoring the pressure of nitrogen inside the cylinder at the time of delivery to the client.

Volume of gas stored in a Nitrogen Cylinder (46.4 L water volume) = Volume of Cylinder
(water holding capacity) multiplied by the pressure of gas inside the cylinder.

As per the invoice, pressure inside the cylinder is 150 Barg, so gas inside one cylinder => 150 X 46.4 = 7000 L or 7m3 ( approx.)

But upon thorough inspection, it was observed that the pressure of the cylinder was 130 Barg, due to which, the gas inside one cylinder becomes 130 X 46.4 = 6000 L or 6m³

After factoring in the real gas inside the cylinder, we found the actual usage was much lower. Please look at the table below:

The above analysis clearly highlights a 15% discrepancy between the customer’s calculated nitrogen flow requirement and the actual flow required.

Pressure Normalisation for Accurate Nitrogen Accounting

For accurate sizing and cost calculations, convert all invoiced units to Nm³ and verify the delivered cylinder pressure. Differences in unit basis (Sm³ vs Nm³) and actual cylinder pressure can significantly distort flow and cost per Nm³.

Quick checklist

• Confirm invoice unit & basis: If billing is done per cylinder, standardise it by converting the quantity into Nm³ of gas.
• Use cylinder specifications: Multiply the cylinder’s water volume by the delivered pressure to estimate the contained gas, then subtract the residual pressure that cannot be utilised.
• Standardise on one basis (Nm³): Convert kg/L/Sm³ to Nm³ before computing consumption, cost per Nm³, and plant sizing.

3. Wastage and Losses with Nitrogen Cylinders

Apart from flow miscalculations, industries relying on nitrogen cylinders also face hidden process losses. A common issue arises from residual gas left inside the cylinder. Since a minimum pressure of 3 Barg is required at the packing machine, any nitrogen remaining below this pressure cannot be utilised, leading to wastage.

Residual Gas Losses

• Unusable leftover: At pressures below 3 Barg, cylinders still contain nitrogen gas that cannot be delivered to the process.
• Fixed refill frequency: Industries often refill cylinders at fixed intervals without accounting for this leftover, adding to the losses.

Loss Calculation

Actual Nitrogen Requirement (After Absstem Audit)

Corrected Nitrogen Requirement (After Absstem Visit)

As we can see, the difference was observable in terms of all parameters, i.e., flow, purity & wastage/loss. By adopting the right PSA nitrogen plant, this particular industry can not only avoid over-investing in CAPEX (savings of ~₹50 Lakhs upfront) but also reduce annual operational expenses by nearly 4.5X every year, as in the case explained above.

Over a 10-year lifecycle, choosing PSA nitrogen based on corrected data prevents what would have been an economic disaster under the client’s original assumptions.

To compare the ROI of your PSA nitrogen plant with that of a Nitrogen Cylinder setup, please use our proprietary Absstem ROI calculator using the link here. 

Conclusion

 This case highlights three critical lessons for industries relying on Nitrogen Cylinders:

1. Check cylinder pressure (130Barg vs 150Barg) to avoid oversizing.
2. Match Nitrogen Purity with application requirements – higher purity ≠ better (ultra-high purity Nitrogen is often unnecessary unless explicitly required).
3. Account for wastage or hidden losses – Leftover gas losses in Nitrogen Cylinder refilling adds up to significant hidden costs.

A PSA Nitrogen Plant with 6-18 months ROI is a smarter, sustainable and cost-effective alternative to Nitrogen Cylinders for long-term industrial applications.

Consult Us

Looking to optimise your nitrogen cost? Contact our experts:

• Email: [email protected]
• Phone: 1800 3010 3394
• Website: www.absstem.com

References

1. Absstem Technologies. (2025). Do We Really Know Our Gas Consumption and Cost?
2. Absstem Technologies. (2025). Do You Really Know Your Gas Consumption and Cost? – Part II (Liquid Nitrogen)
3. Absstem Technologies. (2025). Application of Nitrogen Gas in the Beverage Industry
4. Absstem Technologies. (2024). Understanding Nitrogen Purity in PSA Nitrogen Generators

FAQs

 Cylinder nitrogen often comes at ultra-high purity (99.9997%) beyond actual needs, suffers from hidden losses (residual gas below 3 Barg), and involves logistics and transportation costs, inflating overall cost.

Multiply cylinder water volume X actual delivered pressure, then divide total gas by hours. Example: 46.4 L X 130 Barg = 6 Nm³ per cylinder, not 7 Nm³ at 150 Barg as invoiced.

Residual gas below 3 Barg is unusable, leading to ~2 Nm³/hr loss in typical operations. Fixed refill cycles further increase wastage.

Savings include ~₹50 Lakhs in CAPEX and ~3.8X lower OPEX annually. ROI is achieved within 6-18 months.

No. Most MAP applications only need 99.5-99.9% purity. Using higher-purity cylinders leads to unnecessary costs.