As the most abundant of the air gases, the markets for nitrogen in terms of production, distribution and application are well established.
Nitrogen is utilised across an ever-wider range of end-user industries and while these applications are both cyclical and non-cyclical in nature, demand can be pegged against a slowly improving economic landscape.
The significance of nitrogen can be demonstrated by looking at some of the world’s key commercial industrial gas markets. In the US market in 2016, for example, the most important revenue generating industrial gas was nitrogen, with the sale of this gas accounting for $4.1bn in revenues (20%; total US market of $20bn in 2016). To put this figure in comparison, hydrogen sales generated a further $3.5bn in revenue, with oxygen sales accounting for $3.4bn. This is unsurprising as the US market is one of the most developed markets in the world and was therefore more nitrogen driven than it was oxygen driven.
The slowly improving economic landscape in the US in recent years has led to an increase in demand for oxygen, nitrogen, and argon across various sectors, especially in fabricated metals, automotive, and food; and stainless steel and electronics for argon.
In Japan, another of the world’s biggest regional industrial gas markets, nitrogen is also big business. As the Japanese market has been modernised, the sales of nitrogen have increased to become the largest revenue generating industrial gas in the country, representing over 31% of the total commercial gases business in 2016. To further put this into context, the other atmospheric gases – oxygen and argon – contributed a combined 47% share of revenue, while the rest of the market was relatively fragmented.
In Germany, traditionally the biggest and arguably most robust of the established European markets, nitrogen revenues accounted for around 21% of a $3.2bn market in 2016. Though the most important industrial gas in the German market was oxygen, which accounted for just over $850m in revenue (26.6% market share) in 2016, the sale of nitrogen was clearly a close second.
Key markets for nitrogen include steelmaking and metal-cutting, food processing and transportation, fuels and chemicals production, oil and gas refining, pulp and paper processing, glass making, oxyfuel combustion applications, medical therapies, electronics and more.
Whether it’s for its unique properties in blanketing and inerting applications, or its use as a refrigerant in the grinding of plastics and freezing of food products, the role of nitrogen is essential – in both its gaseous and liquid state.
Liquid nitrogen is a compact and readily transported source of nitrogen gas without pressurisation and has become increasingly popular in the preparation of cocktails, for example, because it can be used to quickly chill glasses or freeze ingredients. Liquid nitrogen can also be applied for the freezing and transport of food products (see below). Liquid nitrogen is also widely used as a refrigerant in applications such as cryogenic grinding of plastics.
Gaseous nitrogen is used in the chemical and petroleum industries for storage tank blanketing and vessel inerting applications, and used extensively by the electronics and metals industries in particular for its inert properties.
In the oilfield
A core end-use of nitrogen is in the oilfield, an application that has never been more prominent. Since the shale oil and gas boom, hydraulic fracturing has spiked – with revived and new interest in enhanced oil recovery (EOR) involving either nitrogen or carbon dioxide (CO2). This is nowhere more relevant than in the US, where the ‘shale gale’ has been blowing through the country’s energy sector in recent years.
Even in the midst of a collapse in oil prices and struggling energy markets in the last 18 months, the role of gases like nitrogen arguably takes on greater significance; the emphasis during such times is to maximise operations and extract every last drop of oil, with industrial gases and equipment at the heart of optimising upstream and downstream activities alike.
The use of nitrogen and CO2 overcomes and mitigates many of the challenges associated with traditional water-based hydraulic fracturing fluids required to exploit this shale gas, by reducing the high volumes of water, chemicals and even proppant. Nitrogen can therefore provide a better approach to increase oil and gas production from tight or water sensitive formations, as well as unconventional reservoirs such as shale, tight sands and coal bed methane. It has also proven effective for well stimulation of shallower reservoir environments.
Crops and cultivation
Nitrogen is also one of the primary nutrients critical for the survival of all living organisms. Nitrogen is present in all living things, including the human body and plants.
Nitric acid (HNO3) is a strong acid often used in the production of fertilizers, while ammonia (NH3) is another nitrogen compound – as its chemical formula suggests – commonly used in fertilizers. Nitrogen is in fact one of the most important ingredients in used fertilizers, and is used for the purpose of increasing soil fertility, promoting plant growth and increasing yield.
Rainfall adds about 10 pounds of nitrogen to the soil per acre per year in the form of nitrogen oxides and ammonium, both of which are formed primarily through the natural process of oxidation by sunlight but also during electrical storms or from internal combustion engine processes. In something of a nitrogen lifecycle, crop residues decompose in soil to form soil organic matter, which itself contains around 5% nitrogen – a percentage of which is then converted by microorganisms to a form of nitrogen that plants can use.
One of the most well versed applications of nitrogen is in the food processing business, used to preserve the freshness of packaged foods.
Nitrogen has numerous applications in the agriculture industry. Cryogenic freezing is perhaps one of the most important areas for nitrogen, however, falling into the food processing and distribution industries. Cryogenic freezing has numerous advantages over traditional mechanical freezing. The main advantage it has is preventing weight loss from dehydration, which translates into a higher quality of preservation for the food product. In addition to this, the application of liquid nitrogen inside a cryogenic freezing system induces the freezing process far quicker, with complete freezing taking minutes instead of hours.
Liquid nitrogen’s application ensures that the formation of ice crystals inside the food product are smaller. In meat products this prevents ‘drip or purge’ when thawed out – if you’ve ever wondered why meat products will lose their moisture when thawing out, this is partly why. In traditional mechanical freezing, ice crystals are larger, and often pierce cell membranes. This means the quality of the food is impacted, which can compromise taste and the overall quality of the product. Cryogenic freezing almost completely avoids this problem. Liquid nitrogen can be used to displace heat from other processes, which helps to reduce microbial growth.
Moving into the food packaging process, heavily dependent on the use of nitrogen gas used in the modified atmosphere packaging (MAP) process, MAP is used to help preserve food inside the packaging, increase shelf life and help the food product remain fresher for longer. MAP can be used on food products that have undergone a minimum amount of processing, including fish, poultry, meat, fruits, and vegetables. MAP is used to change the atmosphere around the food product inside the packaging, thus controlling that atmosphere. All of this is to prevent the variety of ways food can spoil, for example through microbial growth and oxidation.
A variety of gas combinations can be used depending on the food product, the packaging materials used, and the storage temperatures. In some cases, a pure gas – as opposed to a gas mixture – will be applied to the MAP process. Nitrogen is commonly used, and it helps to retain the shelf life of the food product, prevent spoiling, and retain food quality for far longer periods.
Mixing applications also benefit from the application of nitrogen. Certain food products, such as sauces and gravies, can be cooled by liquid nitrogen to stop the cooking processes. In the grinding process, liquid nitrogen is used to remove heat created by friction, increasing the throughput of mills and retaining the flavour and quality of food products moving through the mill. This is particularly important in the processing of food ingredients and additives. Further to this, it is particularly important in the IQF (individually quick-frozen) process, whereby foods are cooled while at the same time applying additional products to the food, such as sauces. Nitrogen is important to both the IQF and non-IQF processes and can be applied with the use of specialised equipment.
Clearly oxygen would be the gas most synonymous with the medical sector, but nitrogen is among a group of gases described as the ‘Cinderella Gases’ – less recognised in medical applications, but no less critical.
Nitrogen has a wide range of lesser known uses in healthcare. Liquid nitrogen, at -195.8°C is used to freeze and store biological tissue, specimens, and blood, for example, while it can conversely be used to freeze and destroy tissue if required, in cryosurgical procedures. These properties of extreme cold and the ability to store biological samples indefinitely without risk of degradation, also have important implications in the realm of human fertility, where semen and eggs are stored for future use.
Gaseous nitrogen is used in pressure systems to power pneumatic surgical equipment, while nitrous oxide (N2O) is used in hospitals and dental clinics as an anaesthetic agent. Additionally, nitrogen is a constituent of almost every major class of drugs, including antibiotics.
There is also a less cheerful application for liquid nitrogen in the medical world – as evidence in medical litigations. If treatment goes wrong, the patient or the family can hold the medical professional or the facility responsible and seek damages. A duplicate sample that has been preserved using liquid nitrogen and stored for this very purpose, however, means the tissue can be tested again – even years later – to verify the original result.
Wholebody cryotherapy (WBC) is a revitalising experience which involves spending a short timeframe (approx. 2-4 minutes) inside a specialised chamber at -135°C, cryogenically cooled by liquid nitrogen.
Launched in Japan in 1978, cryotherapy is nothing new and has been a popular treatment in Eastern Europe for many years. WBC is now becoming a favourable experience in Western Europe too, and has been in high growth mode of late.
The last 18 months have seen WBC move from an innovative and arguably alternative new therapy to a rapidly accepted and adopted therapy technique in the sporting field. In football alone, for example, Watford FC became the first Premier League football club to install and use a permanent cryotherapy chamber in 2016 thanks to a new business venture between BOC and CryoAction; fellow London club Fulham FC then became the next club to fully embrace WBC, adopting a tailored PolarFit® Care cryotherapy vessel developed by Air Products and ProCare in March 2017; and Spain’s Carburos Metálicos has become the official supplier of cryochamber therapy for Sevilla Fútbol Club (FC), under which agreement it will supply an individual cryochamber and the necessary advice to the team.
WBC is understood to induce a range of both physiological and psychological benefits, and is certainly on the rise in elite sports where athletes use cryotherapy as part of their programme of training and recovery. Benefits are said to include reduced recovery times, improved body preparation, stress relief and help aid the treatment of sporting injuries. The therapy is seen as a major improvement from traditional ice bath methods in sporting circles, for example, which suddenly submerges the athlete in ice-cold water, as the dryness of cryotherapy treatment negates any potential shock factor.
Metallurgy and manufacturing
Nitrogen is often used in manufacturing stainless steel, electroplating processes in order to make it stronger and more resistant to corrosion.
Nitrogen can also be used in a range of manufacturing applications, from making light bulbs, serving as an inexpensive substitute for argon in incandescent light bulbs, to the production of transistors, integrated circuits, and diodes (semiconductor applications). Dried and pressurised nitrogen gas is used as a dielectric gas for high voltage equipment too.
When an exclusive supplement from gasworld broke ground with the first real exploration of the liquid air concept in October 2012, few would have been familiar with the notion and its potential; a proven energy storage technology that could play a critical role in Britain’s low carbon energy future.
In the half-decade that has followed, the liquid air project has gathered considerable momentum, both in the mainstream and technical press and behind the scenes on its finer details – all of which has culminated in a series of government-backed reports.
The use of liquid air could increase UK energy security, cut greenhouse gas emissions, and create a storage industry worth at least £1bn pa and 22,000 jobs, one report found. Published by the Centre for Low Carbon Futures (CLCF), it concluded that liquid air technologies could also significantly increase the efficiency of road vehicles, particularly in Britain’s fleets of buses, vans and refrigerated lorries.
It has also often been pointed out that this could have significant benefits – and added revenues – for the gases industry. The production of liquid nitrogen and liquid oxygen, the main components of liquid air, has of course been pioneered by the industrial gases industry for over a century. The properties of liquid nitrogen and liquid air are similar, so it is felt that a cryogenic energy vector could be provided by either; the gases industry has surplus liquid nitrogen production because there is four times as much nitrogen as oxygen in the atmosphere, but much less demand for it commercially.
Liquid air is based upon the science that air can be turned into a liquid by cooling it to around -196ºC using standard industrial equipment. Around 700 litres of ambient air becomes one litre of liquid air, which can then be stored in an insulated vessel. When heat (including ambient or low-grade waste heat) is reintroduced to liquid air it boils and regasifies, expanding 700 times in volume. This expansion can be used to drive a piston engine or turbine to do useful work. The main potential applications are in electricity storage, transport and the recovery of waste heat.
Nitrogen is available both in liquid and gaseous forms. In large quantities it is derived from ASUs and delivered via liquid nitrogen tankers. But with many oil and gas projects based in remote locations, for example, deliveries of nitrogen to the point-of-use is a major undertaking. With the advent of low cost and reliable nitrogen gas production using air separation in the gaseous phase, many oil and gas projects have opted for in-situ nitrogen generation. In recent years, it is understood that many other industries have increasingly turned to onsite nitrogen generation to combat challenges of either remote location or the scale of supply required.
Advances in pressure swing adsorption (PSA) technologies, as well as increasing demand for in-situ gas generation in a range of applications, are driving a proliferation of air gas production via these systems. This is particularly the case in the medical field, for example, where PSA oxygen generation is fast growing as a popular alternative to centrally produced and distributed oxygen. Though commercialised in the 1970s, PSA oxygen concentrators for the supply of medical gas distribution systems have especially grown on the worldwide market in the last 20 years.
In PSA and membrane nitrogen generation systems, the cost of generation of nitrogen is the cost of the power running the air compressor. For systems of up to 5,000 nm3/hr, when compared with cryogenically produced nitrogen, both the investment cost and the cost of nitrogen generation is significantly lower. PSA uses Carbon Molecular Sieves (CMS) to separate nitrogen and oxygen. CMS adsorbs the oxygen under pressure and allows nitrogen to pass through as the product gas.
PSA is suitable when the purity requirement of nitrogen is higher than 99%. Due to the physical plant size, PSA plants have a constraint on the volume of nitrogen that can be produced from a single system. Even though very large PSA nitrogen plants of volumes as high as 2,500 nm3/hr have been built, it is advisable to split large requirements into multiple PSA systems for operational redundancy.
Having said this, cryogenic distillation is still currently the only commercially viable technology that will economically produce thousands of tonnes of oxygen per day, with cryogenic ASU performances improving significantly over the last 40 years. It has previously been estimated that power consumption – the biggest air gas industry cost – has been cut almost in half in this time, while distillation column productivity has multiplied as much as three-fold.
Transporting cryogenic liquid bulk can be done in various ways, via the many different ‘bulk packages’ that exist in the market. Traditional modes for road transport revolve around the cigar-shaped liquid bulk cryogenic trailer that is so recognisable to us all. These are generally low and mid-size pressurised trailers used for relatively short distances and therefore short transit times between the ASU and the customer. In Europe, for example, the distribution tends to take place in a radius of just 300km from the source.
In other geographies, however, where there are much longer distances involved and an array of remote customer locations (such as the African continent), the distances covered and delivery times taken are far greater. In such circumstances it is not uncommon to use a bulk ISO container, used to transport liquid bulk over larger distances, mostly by vessel but also by rail.
Ultimately, the higher the payload, the more product can be delivered, and the lower distribution costs will be, as fewer rounds are required to deliver the same product volumes. In the past gasworld has understood that it is commercially viable to transport lower cost liquid nitrogen within a 400km range, while liquid oxygen is ‘agreeable’ to be moved up to 600km in range.