Nitrogen Generators for the Food and Beverage Industry
A nitrogen generator produces the gas for food and beverage processes on your own site from compressed air, at grades from 97 % to 99.999 %. Whether generating your own beats a liquid tank and cylinders comes down to the purity grade your process calls for and to what that grade costs in compressed air every operating hour. Both are set out here.
Where a Nitrogen Generator Is Needed in a Food Plant
Nitrogen is a process gas in a food or beverage plant, and it does its work at several points. It suits the role because it is unreactive and adds no flavour of its own. In storage and process tanks the gas keeps oxygen out of the headspace, so that fats do not oxidise and aroma, colour and vitamins stay in the product. For edible oils and fats this protection inside the vessel is the main reason to work with nitrogen at all, because rancidity starts in the tank and not in the pack.
In transfer and conveying, nitrogen does the same job in motion. It pushes product through lines and out of vessels, and it moves powders pneumatically without letting atmospheric oxygen reach them. Filling and beverage production add the steps the plant already knows: inerting vessels, pre-pressurising bottles and cans before filling, purging bottles, sparging tanks and displacing product.
In storage and preservation, nitrogen works over time instead of over a process step: inside closed vessels and in storage rooms it lowers the oxygen share and slows down what oxygen does to the product. How far the share has to come down, and what that means for shelf life, depends on the product, the vessel and the storage period.
Nitrogen does the same job at further points in the plant:
| Process | What the nitrogen does there |
|---|---|
| Milk powder and oxidation-sensitive powders | conveying and blanket gas during production and handling |
| Chocolate production | keeps oxygen away from cocoa butter, whose fat would otherwise oxidise |
| Fruit and vegetable storage | lowers the oxygen share in the store, controlled-atmosphere storage |
| Wine | protects against oxidation in the tank and during transfer |
| Brewing | can take over part of the work otherwise done by carbon dioxide, depending on the process step |
Packaging under a protective atmosphere is a separate step and has a page of its own. How much residual oxygen may stay in the pack, which purity band suits it, and how much flush gas a line draws is covered on Nitrogen Generators for Food Packaging.
Food Grade Nitrogen: The Limits Set by E 941
Food grade is a matter of specification, not of the highest purity you can reach. Nitrogen is listed as a food additive under the number E 941, and the Annex to Regulation (EU) No 231/2012 sets out the values that additive has to meet. There are six of them, and two depend on the purity grade a generator is set to.
| Parameter | Limit under Regulation (EU) No 231/2012 |
|---|---|
| Assay | not less than 99 % |
| Oxygen | not more than 1 % |
| Water content | not more than 0.05 % |
| Carbon monoxide | not more than 10 µl/l |
| Methane and other hydrocarbons, calculated as methane | not more than 100 µl/l |
| Nitrogen dioxide and nitric oxide | not more than 10 µl/l |
Set that oxygen limit against the data sheet for the range. The limit is not more than 1 % oxygen, and purity grade 99 % is quoted at 10,000 ppm residual oxygen, which is that same value. It is reached at the lowest air factor among the grades that meet the limit. That puts this grade arithmetically on the limit rather than below it. Whether your food safety system requires headroom is your call, and anyone who needs it moves up one step. How tightly the plant holds its setpoint in continuous duty, at start-up and under load changes therefore belongs in the sizing, to be settled before the grade is chosen. For assay and oxygen, what counts in the end is the grade your own product specification calls for.
The other four values are decided by the compressed-air treatment ahead of the generator. Water, carbon monoxide, nitrogen oxides and hydrocarbons either arrive with the compressed air or they do not, and that is down to the dryer and the filter stages, not to the carbon molecular sieve. Two requirements run side by side here and are easily confused: the compressed-air class the generator asks for protects the molecular sieve, while the treatment that holds your four values follows the limits in the table above. Which dryer and filter chain satisfies both depends on your air quality at the inlet and belongs settled before you buy. The section “What the Generator Needs on Site” sets out how that chain is built. For orientation, because the terms turn up in specifications: Regulation (EC) No 1333/2008 lists packaging gases and propellants as functional classes of their own, both expressly as gases other than air. A packaging gas is introduced into a container before, during or after the food is placed in it; a propellant expels a food from a container.
On-site generation moves the evidence, it does not remove it. With delivered gas, quality arrives as a certificate alongside the delivery. With a generator, purity is measured while the plant runs and can therefore be recorded, and a deviation shows up during production instead of on paper afterwards. Checking that record against your own product specification and your own food safety system stays with you as the operator.
What Higher Purity Costs in Compressed Air
Every purity step has its own air factor, that is, its own ratio of compressed air to nitrogen produced. The factor depends only on the purity setting and is identical across all 18 model sizes in the range. That makes the purity decision something you can calculate before the purchase instead of noticing it later on the electricity bill.
| Purity | Quality grade | Residual oxygen | N₂ output across the range | Air factor | Compressed-air demand |
|---|---|---|---|---|---|
| 97 % | not stated in the data sheet | not stated in the data sheet | 10.7 to 1,709.1 Nm³/h | 2.3 | 24.6 to 3,930.8 Nm³/h |
| 98 % | not stated in the data sheet | not stated in the data sheet | 8.6 to 1,373.6 Nm³/h | 2.3 | 19.8 to 3,159.4 Nm³/h |
| 99 % | 2.0 | 10,000 ppm | 7.1 to 1,134.0 Nm³/h | 2.6 | 18.5 to 2,948.5 Nm³/h |
| 99.5 % | 2.5 | 5,000 ppm | 6.2 to 990.3 Nm³/h | 2.9 | 18.0 to 2,871.9 Nm³/h |
| 99.9 % | 3.0 | 1,000 ppm | 4.1 to 654.9 Nm³/h | 3.4 | 13.9 to 2,226.6 Nm³/h |
| 99.99 % | 4.0 | 100 ppm | 2.2 to 351.4 Nm³/h | 4.6 | 10.1 to 1,616.4 Nm³/h |
| 99.995 % | 4.5 | 50 ppm | 1.7 to 271.5 Nm³/h | 5.2 | 8.8 to 1,412.0 Nm³/h |
| 99.999 % | 5.0 | 10 ppm | 1.2 to 191.7 Nm³/h | 6.4 | 7.7 to 1,226.7 Nm³/h |
Compare the air factor column within the band that is open to your product. The 97 % and 98 % steps sit below the E 941 assay value of 99 % and are therefore only an option where the gas does not contact food. Within the food grade band, 2.6 at 99 % stands against 6.4 at 99.999 %: the same volume of nitrogen costs about two and a half times the compressed air at the top step, and it costs it every operating hour. So the purity grade comes out of your product specification. Once that figure is fixed, output times air factor gives the compressed-air demand, and that tells you whether the compressor you already have is enough.
If you buy liquid nitrogen today, you start out with the wrong unit in the building. Your delivery notes are in kilograms or litres of liquid nitrogen; the table above is in normal cubic metres of gas. Between the two sits the normal density of nitrogen, which your gas supplier states on the delivery note or in the product data sheet. An annual quantity becomes an hourly figure when you divide it by the hours in which gas is actually drawn, not by 8,760. Those two steps get you into the table with your own paperwork.
The second item to settle is simultaneity. Adding up the peaks of every process buys a plant that never runs at load. Where several processes with different draw profiles come together, the calculation is harder than on a single line: tank inerting draws steadily, pneumatic powder conveying draws in the rhythm of the conveying batches and therefore in bursts, a bottle purge draws briefly and hard, a storage-room atmosphere draws almost nothing and runs continuously. In a powder plant, conveying is the peak consumer even where tank inerting draws the larger quantity over the day. Where the purity grades they need also differ, it is worth asking whether they all have to hang off the same supply, or whether two lines together cost less than one set to a high grade.
You Get Back a Purity Grade, a Model Size and an Air Demand
To start with, your current consumption and the processes it feeds are enough. That shows which purity grade is sufficient and what compressed-air demand goes with it. If output, purity and operating hours are already to hand, we come back to you with a sizing proposal.
On-Site Nitrogen Against Liquid Tanks and Cylinders
A liquid tank and a cylinder bundle both deliver the purity you ask for. What you pay for is not only the gas but the supply around it: tank rental runs through the quiet weeks, boil-off runs every night, supply contracts carry price escalation clauses, and the cylinder change falls due while the line is running. On top of that there are three items that fix the price for years: the supplier’s annual price adjustment, the long-term tank contract, and follow-on costs after the purchase that were not in the quotation.
On-site generation swaps that for an investment and an electricity bill. Compared with an ongoing liquid nitrogen supply, a generator typically pays for itself in two to three years. The comparison is on-site generation against exactly that supply route; an extension of your compressed-air station is not inside the span and belongs in your own calculation. You are also swapping one price risk for another: instead of your gas supplier’s annual adjustment you carry the electricity price, which you buy anyway and which no take-or-pay contract ties down. Whether the calculation works out in your plant depends on your consumption profile, operating hours and electricity price, which is why it is worth doing with your own figures rather than with a rule of thumb.
What the Generator Needs on Site
The generator sits in a chain, and you supply two links of it yourself. The chain runs: compressed air, treatment, generator, buffer vessel, point of use. The compressed air and its treatment come from your side of the fence, and that is exactly where the part of gas quality that does not hang on the purity setting is decided. An undersized dryer brings moisture into the plant and thereby shortens the service life of the carbon molecular sieve. The buffer vessel covers what an average figure never shows: cleaning and start-up peaks, format changes and the start of a batch.
One point belongs to the location rather than to the plant: nitrogen displaces oxygen. For the room the generator stands in, ventilation and oxygen monitoring therefore belong in your risk assessment, and both are cheaper to solve before the site is chosen than afterwards.
The principle itself is quickly explained. Treated compressed air passes through the molecular sieve, which adsorbs oxygen and moisture far faster than nitrogen, while the second vessel regenerates at lower pressure. Purity is a setting rather than a fixed property of the machine. The page PSA Nitrogen Generator works through the process step by step.
NITROBERG® Model Sizes for Food and Beverage Plants
From process to machine there is a single question: what volume at what purity grade? The NITROBERG® range covers 97 % up to 99.999 % and delivers between 1.2 and 1,709.1 Nm³/h of nitrogen, depending on model size and the purity it is set to. That band covers the small plant with one filling line as well as the site that supplies a tank farm, conveying and several lines from one source. The full figures per model size are on the Nitrogen Generators overview.
Where a site has no suitable compressed-air network, the nitrogen generation package brings generator, air generation, treatment with a DRYBERG® dryer, storage and control together in one pre-assembled unit, as plug-and-play configurations for NITROBERG® 500 to 900. Above those sizes we size the plant for your site. The single unit and the complete package come from one source within the BERG Group. Applicable NITROBERG® pressure equipment is conformity assessed under PED 2014/68/EU within the certified scope.
Follow-On Costs and Service After the Purchase
Standard Wear Parts From the Open Market
Filters and wear parts are off-the-shelf items from the open market, not part of a proprietary programme. You can compare quotes and put a change into a planned maintenance window instead of waiting for a delivery date. Over the service life that usually matters more than the difference in purchase price.
Three Years of Warranty, Up to Five With a Service Contract
Warranty runs three years as standard, and up to five years in combination with a service contract. The service contract sets the intervals, so the dates fit your production planning instead of falling into a running batch.
Service From One Source
Service and spare parts come from one source within the BERG Group, with engineering and manufacturing in Germany. Outside Germany a local point of contact comes on top in most markets. That counts for most at sites with no maintenance team of their own.
Direct Access to Engineering
Sizing, compressed air and documentation you discuss with the engineers who design the machines, not with a call centre: +49 2151 568 9550. Commissioning and operator training are included, so that after handover your shift team runs the plant itself.
FAQ: Nitrogen Generators in the Food and Beverage Industry
Nitrogen is listed as a food additive under the number E 941, and the Annex to Regulation (EU) No 231/2012 sets out its specification: six values, from assay and oxygen through water to carbon monoxide, nitrogen oxides and hydrocarbons. The limits are in the table on this page. Food grade is therefore a matter of specification, not of the highest purity you can reach. Which value is met at the point of use depends on the purity grade set and on the compressed-air treatment ahead of it.
The purity grade comes from your product specification. Which grade a given food process runs at is product and plant specific: the same operation calls for a different figure with a different product, a different vessel or a different storage period. There is no general process-to-grade mapping. The reliable route runs through the target value in your own specification and through the question of what it costs in compressed air. The figures for each purity step are in the table on this page, and which target value holds for your product is something we work out with you when we size the plant.
In storage and process tanks nitrogen protects the product in the headspace, in transfer and conveying it displaces and moves the product, and in filling it inerts and pre-pressurises bottles and cans. Purging and sparging in beverage production come on top, as does storage and preservation, where it lowers the oxygen share in vessels and storage rooms. The packaging step itself is covered on Nitrogen Generators for Food Packaging.
Two figures decide that, and the quality of the air is overlooked more often than the volume. NITROBERG® requires compressed air to ISO 8573-1:2010 Class 1.4.1 at 7 bar(g), because oil and residual moisture in the air stream age the carbon molecular sieve prematurely. The volume follows from output times air factor, and the air factor depends only on the purity setting: identical across all 18 model sizes, from 2.3 at 97 % to 6.4 at 99.999 %, starting at 2.6 within the food grade band from 99 % up. A lower purity grade therefore cuts demand more than proportionally.
The difference lies in the specification it is measured against. Six values are set for the additive E 941. Two of them depend on the purity grade: the assay of not less than 99 %, and the oxygen content of not more than 1 %, which corresponds to purity grade 99 % at 10,000 ppm residual oxygen and therefore sits arithmetically on the limit. Anyone who needs headroom moves up one step. The other four, water, carbon monoxide, nitrogen oxides and hydrocarbons, are decided by the compressed-air treatment ahead of the generator. Buying food grade therefore means both: the right purity grade and treatment that suits the remaining values.
Delivered gas comes with a certificate per delivery. With on-site generation, purity is measured while the plant runs and can be recorded, so a deviation shows up during production rather than afterwards. Checking that against your own product specification stays with you, and so does deciding where the measurement point sits and what is monitored continuously or checked periodically. Those points belong in the sizing discussion, because sampling points cost less before the pipework goes in than after.
The buffer vessel bridges short interruptions and buys reaction time. How large it has to be follows from the longest interruption your process can take, and that question is settled before the model is chosen. Any reserve supply beyond the buffer we work out with you when we size the plant, with your plant concept and the requirements at your site in view. The decision on it stays yours as the operator.