Some of the most strategic decisions an organisation will ever have to make focus on sourcing. And when it comes to investment in compressed air capital plant, operators will be seeking solutions that can help to both lower production costs and improve energy efficiency.
This kind of win-win seems like a tall order; but, says Keith Atkinson, Global Product Manager, Nitrogen Generation at Gardner Denver, one emerging way to make savings and increase control of the manufacturing process is to invest in an on-site nitrogen generation system, using existing compressors to convert air to guaranteed purity nitrogen. If implemented properly, this process can save operators up to 90% of the cost of bought-in gas.
Why nitrogen?
Nitrogen is widely used in the pharmaceutical industry to keep products or systems both dry and sterile. As an inert gas, it can reduce the risk of fire in volatile manufacturing environments, while blanketing products with nitrogen can also help to preserve or even improve the quality of the pharmaceuticals.
The gas essentially displaces the oxygen that is present in the air, helping to limit harmful side-effects such as corrosion, oxidation or bacterial growth. As well as drugs and other treatments, the test kits supplied to doctors’ offices, blood supplies, specimen containers and a wide array of other medical devices are also frequently packaged with nitrogen gas.
With so many uses, it’s easy to see why nitrogen gas is being used in a diverse range of applications in the pharmaceutical industry. However, most manufacturers currently purchase their nitrogen from a supplier, either as gas in small high-pressure cylinders or in liquid form, stored in mini-tanks or bulk storage vessels.
Obtaining and maintaining a readily available supply of nitrogen in sufficient quantities is not without its drawbacks. As well as finding a reliable vendor and arranging deliveries and payment, companies need to find a suitable space to store the gas, as well as to establish a thorough procedure to monitor and manage their supply safely. There are alternatives to simply buying the gas in, though. It is possible for site operators to install an on-site nitrogen generation system that can help to dramatically reduce a site’s supply chain costs.
Benefits of on-site generation
Using an on-site generation process converts compressed air to guaranteed-purity nitrogen. The majority of generators in this kind of environment will use pressure swing adsorption (PSA) technology, in which pretreated air taken from standard industrial compressed air is filtered through a carbon molecular sieve. This preferentially adsorbs oxygen, water and carbon dioxide, essentially removing these and other trace gases, leaving just the pure nitrogen to pass through to the application itself.
This process enables pharmaceutical companies to optimise their current compressed air system, mapping production levels to meet on-demand supply, and gives them complete control over the volume and flow of the gas required. The fact that this can be produced from an existing compressed air system with a minimum of extra floor space is an additional bonus.
By reducing the amount of gas that needs to be bought in, minimising waste and eliminating the need for storage, on-site nitrogen generation can also reduce supply costs by as much as 90%. A company that currently uses liquid nitrogen can expect an on-site system to pay for itself completely in less than 2 years, whereas one that buys in gas cylinders could have a payback period of as little as 1 year.
Key considerations
Although there are many benefits to producing nitrogen on-site, there are a number of factors that manufacturers will have to consider before investing in a system. The first of these is the purity of the gas that is needed on the site, as each application demands different quality levels depending on whether the gas comes into direct contact with products during production, or if they do so indirectly to form packaging or for general blanketing.
The site limitations, particularly regarding available floor space and installation costs, should also be taken in to account. Although the amount of floor space a nitrogen generator will actually take up is minimal, selecting a system of the correct size and housing can help to avoid any expensive civil engineering projects.
Processors should also ensure that the nitrogen generation equipment can be easily integrated into existing compressor installations, which will also minimise their overall capital expenditure. The gas flow rate should be matched accurately to the application requirements, so that the required amount of nitrogen is being generated without any excess being wasted. This will help to improve efficiency while also ensuring that sufficient gas is always available, maximising the site’s production uptime.
Finally, energy consumption is naturally a major consideration in the purchase of any new processing equipment. Running an on-site nitrogen system will inevitably use significantly less energy to generate the nitrogen required on-site than it takes for a supplier to produce and deliver the same amount.
In summary, for a modest initial investment, on-site nitrogen generation can reduce a site’s overall carbon footprint, cut costs and provide unrivalled control of a vital portion of the production process.