Keep close to your supply

James Heseltine explains how the latest gas generation technology can help increase efficiency and cut costs in laboratory applications

A continuous supply of high purity gas is essential for a wide range of laboratory processes, including spectroscopy, gas separation and various chemical analyses. The gas used in these applications is typically supplied and stored in high pressure cylinders, liquid mini tanks or bulk storage vessels. These methods are generally costly, inconvenient and introduce a number of other problems that need attention. One solution is to replace these processes with the latest gas generation technology, which can be installed on-site to provide a readily available source of hydrogen, nitrogen or clean, dry air.

A considerable amount of time, resources and money is required when buying-in gas for laboratory applications. There is the need to source a reliable supplier, find somewhere in the lab or on the premises to store the gas, and a network of gas pipes to install and maintain. At a time when laboratories are looking to reduce their overheads and streamline their operations, the rental, refill, delivery and order processing costs of the various storage containers can add up to a considerable ongoing expense. Furthermore, variations in gas prices make it difficult to budget for these costs effectively.

Using an external supplier and storing gas on-site can also be extremely inconvenient; for instance, it is difficult to guarantee the reliability and quality of the gas supply. If a problem arises with the supplier, laboratories often have no backup plan, bringing urgent work to a standstill. Furthermore, laboratory staff are often required to handle heavy, high pressure cylinders, introducing significant health and safety risks storing and handling high pressure gases on-site requires adequate safety measures to be taken, escalating costs still further.

In addition to the cost and inconvenience of conventional gas supply methods, there are a number of other issues that need to be addressed, depending on the specifics of the application. For example, the production, containment and transportation of gas can have a serious negative impact on the environment – a great deal of energy is consumed throughout the production and delivery process and much carbon emitted as a result.

The inefficiency of traditional gas supply methods has led many laboratories to investigate ways to obtain an affordable, reliable and convenient supply of gas for their applications. One increasingly popular solution is to install one of the latest gas generation systems, which enable users to produce their own supply of hydrogen, nitrogen or clean, dry air on-site.

While these integrated systems work in different ways, all are designed to produce high quality gas for use in the laboratory. Nitrogen generation systems use a principle known as pressure swing adsorption (PSA) to turn a compressed air stream into nitrogen. A pre-treated stream of air from a standard industrial compressor is essentially “sieved” so that oxygen and other trace gases are adsorbed while nitrogen is allowed to pass through.  While using a carbon molecular sieve (CMS) for air separation is not a new idea, the radical design and control system employed on these latest nitrogen generators has maximised gas output and reduced compressed air consumption to make the new units significantly more effective than previous filtration systems.

The latest hydrogen generators on the market work slightly differently, producing hydrogen from water and electricity - however, the process is just as efficient. The generators use an ion exchange membrane and the electrolytic dissociation process to break down the de-ionised water supply into hydrogen and oxygen. The oxygen is released into the air, while the hydrogen is retained for use. A long-life desiccant cartridge purifies the hydrogen still further, so that it meets the grade required for use in the laboratory and ensures consistent and reproducible results. This method of producing hydrogen eliminates the need to use liquid electrolytes, such as caustic solutions.

In addition to nitrogen and hydrogen generators, systems are now available that can produce “zero air” (clean, dry air with an ultra-low residual methane content) for combustion detector applications, and CO2-free air for applications such as purging of FT-IR spectrometers and TOC analysis. The zero air generators work by using a combination of high performance filtration and catalytic technologies, while the CO2-free air systems combine filtration with PSA.

Being able to produce laboratory quality gases on-site and take control of your gas supply, as opposed to having to rely on a third party, can have many important benefits for a laboratory. Firstly, there is the reduced cost; unlike high pressure cylinders, liquid mini tanks or bulk storage vessels, once a nitrogen generation system has been purchased there are no ongoing costs. If a lab using liquid nitrogen were to switch to gas generation technology, they could expect the new system to pay for itself in less than three years, while for a facility using cylinders, the pay-back period could be even sooner; just 12 months in many cases.

In addition to the cost benefits, the latest gas generation units offer a much more convenient solution than sourcing gas externally and storing it on-site. The latest compact systems can be installed quickly, easily and at minimum cost and disruption, simply requiring a pre-treated compressed air stream or de-ionised water supply to start producing gas.

Generating its own gas on-site also puts a laboratory in control of its gas supply and increases its productivity. The lab can choose to produce as much or as little gas as needed, and at a consistent, measurable cost. To ensure there is always a ready supply of gas for use in the lab wherever and whenever it is needed, the latest modular systems enable additional banks of units to be set up quickly and easily on-site. This guarantees 100% back up, and secures the supply when routine maintenance on one set of systems is required. Furthermore, using a modular gas generation system allow extra banks to be installed at minimum cost, so as the lab’s requirements change, its gas production system can grow to meet them.

One important point to note is the improvement to employee safety that can be achieved almost instantly. Using the new gas generation systems completely eliminates the safety risks of storing, handling and changing cylinders. With no high pressure gas containers required on site, the lab becomes infinitely safer for staff. In addition to the time and resources saved by avoiding considerable health and safety measures, there are cost benefits too, both in streamlining procedures and avoiding the expense of potential legal action in the event of an incident.

Of growing importance to laboratories is the environmental impact of its

“In addition to the cost benefits, the latest gas generation units offer a much more convenient solution than sourcing gas externally and storing it on-site.”

processes. On-site gas generation is much safer for the environment than conventional supply methods, as cutting out the need to transport the gas from the supplier to the laboratory minimises the  lab’s carbon. Producing its own gas supply is a far more sustainable way for a lab to meet its gas supply needs, requiring a fraction of the energy of more traditional options.

With laboratories increasingly looking for ways to reduce their costs while upholding, or even improving, their levels of efficiency and safety, the gas supply can be a good place to start. Generating hydrogen, nitrogen or clean, dry air on-site can help a lab take control of its gas supply, ensuring a constant flow and therefore avoiding unnecessary day-to-day disruption. With an expected pay-back time of as little as one year, the latest gas generation technology can have significant effect on a lab’s bottom line, and help it to operate in a safer, more efficient and more environmentally friendly way.