Never break the chain

Supply of high quality gases is vital to many laboratories – so why not have your own onsite supply?

FOR A BUSY European laboratory carrying out a range of analytical processes, maintaining supplies of high quality specialty gases is vital to ensure that tests are completed promptly and accurately. A break in supply could affect productivity levels, causing costly downtime.

Zeeuws-Vlaanderen Laboratory in Holland is one of Europe’s leading testing houses for soil and water samples, fertiliser, plants, fodders and foodstuffs. Each year the company analyses over 200,000 samples and provides reports and advice to individuals, farms, auctioneers, supermarket chains and energy companies, among others.

Analytical gases are used in a variety of ways to perform complex analytical processes at the state-of-the-art laboratory. In gas chromatography (GC/MS), for example, helium and argon are used as the carrier gas - carrying the sample being analysed through the analysis column. In liquid chromatography (LC/MS), the liquid in which the sample is dissolved is atomised with the help of propellant gases such as nitrogen and hydrogen. Nitrogen is also used as a blanketing gas to seal off the sample being analysed from the surrounding air. In addition, gases such as helium and hydrogen are used in flame ionisation detectors (GC-FID) in the analysis of fertiliser samples, for example.

As part of its commitment to quality, the laboratory uses certified gas calibration mixtures supplied by an ISO 17025 accredited laboratory and has chosen to source these from Air Products’ European Specialty Gases Laboratory.

Zeeuws-Vlaanderen Laboratory is a substantial user of specialty gases. While only a small amount of gas is used for each analysis, the laboratory’s overall consumption of argon and nitrogen has increased sharply in recent years due to the large number of samples being analysed. Liquid argon and liquid nitrogen consumption has risen to around 20,000 litres per year and liquid oxygen consumption to 3,000 litres per year.

Jos Heijens, director at Zeeuws-Vlaanderen Laboratory, said: “On average we were using around 400 cylinders of argon, 400 cylinders of nitrogen and 60 cylinders of oxygen each year. A lorry had to come almost every week to exchange cylinders. As well as being an administrative burden, our technicians were also spending a lot of time connecting and disconnecting cylinders. In principle, these operations could have affected the continuity of our work, due to the loss of pressure, for example.”

Working in partnership with Air Products, a decision was taken to install onsite

Zeeuws-Vlaanderen Laboratory in Holland is one of Europe’s leading testing houses.

storage tanks for those gases with the highest consumption levels. The company offers a range of supply options, including the CryoEase service – a microbulk supply service, which allows gases to be stored and monitored onsite.

Two 950 litre tanks for liquid argon and nitrogen and one 230 litre tank for liquid oxygen were installed in a fenced enclosure behind the laboratory.

Air Products also supplied mixing technology to blend nitrogen and oxygen from the tanks, for use as a purge gas when flushing out the control system and analytical equipment. In the past this was done using atmospheric air, which was pressurised using a compressor. Using a mix of pure nitrogen and oxygen instead of atmospheric air, means no impurities are left behind that could influence analytical results.

This new gas supply and storage solution has reduced the frequency of deliveries to the laboratory dramatically and has brought other advantages too.

Jos Heijens explains: “The amount of time taken replenishing supplies of analytical gases has reduced substantially. Argon and nitrogen supplies are now delivered once every three to four weeks.

“The gases are delivered at the correct pressure, which means that the onsite

Analytical processes are carried out to test a variety of samples.

storage tanks can be filled at any time of day or night and there is no need to stop work. Although a relatively small amount of gas is used per analysis, maintaining supplies is obviously critical and this supply solution gives us peace of mind.”

Recently, Air Products advised the laboratory on its planned investment in a new pipeline system, to deliver each analytical gas directly from the onsite tanks to its point of use. User-friendly pressure-reducing valves have been incorporated, allowing the technician to bring the gas to the correct working pressure, according to each process application.

The new supply solution is helping to deliver efficiencies in a number of ways. Time spent managing gas supplies and switching cylinders has been significantly reduced and there is less waste in terms of gas residuals being returned along with used cylinders. In addition, the system provides an opportunity to manage costs more efficiently as only the gas that is used is paid for.

For added convenience, the gas supply system is managed and maintained by Air Product’s engineers to ensure it operates efficiently at all times. Wilfried Braspenning, CryoEase service manager at Air Products, adds: “Companies should consider switching to a microbulk gas supply system such as CryoEase if they are using more than about 10 large cylinders each month. For gas mixtures the threshold is around 20 cylinders per month because two or more storage tanks and a mixing system are required.”

He concludes: “Continuity of supply brings reassurance for laboratories and other users of analytical gases, ensuring that there is a ready-to-use supply of high quality gas products, capable of delivering accurate and reliable test results time and again.”