The packaged gas industry is faced with market volatility, changing supply and demand, and in many cases, skyrocketing costs. Recently, both helium and oxygen have experienced highs and lows in cost and availability, further emphasizing the need for increased throughput improvements and cost reductions in gas booster technologies.
Helium is the largest sector in the inert gases, followed by argon. Helium, which has been broadly used in science and industry due to its availability and cost, has faced a critical shortage and even today, costs are at an all-time high. The demand for helium is driven by ever-increasing MRI scans along with increased usage of helium in the semiconductor and electronics industry. In 2019, many scientists were forced to shut down superconducting magnets due to a shortage of helium, which is used as a shielding gas. The COVID-19 pandemic actually improved supply as the sharp decline of celebration and party balloons opened up some 10% of the helium supply. But the price increases caused by the shortage have remained unchanged.
Oxygen, of course, was a critical resource in the fight against COVID-19, while manufacturers still needed to meet industrial needs, for production of steel, plastics and textiles, brazing, welding and cutting. Industrial gas suppliers reported 5-10 times the usual demand.
In addition to supplying industrial gases for a wide range of needs, industrial gas suppliers must increase throughput and efficiency to ensure cost-effective packaging of helium, oxygen, and other gases.
Most industrial gases are commonly delivered under pressure at 2,000 — 2,600 psi in steel cylinders. If the gas is to be used at low pressure, e.g., welding, the pressurized supply is easily piped and controlled to the point of use with simple valving. However, if the end use requires the gas under pressure, the supply cylinder pressure cannot be utilized after it has fallen to the level of the end-use pressure. Remaining gas will be wasted unless it is boosted. If the application requires a pressure greater than common supply cylinder pressures, a booster can often be justified not only because of utilization of the gas, but also because it will eliminate the need to purchase the gas in special, higher pressure, more costly supply cylinders.
Large industrial gas users can further reduce gas costs by purchasing and storing their gas as a liquid in low pressure insulated containers (dewars). The gas will vaporize when exposed to ambient temperature. Usually, a simple finned assembly developing 50 — 150 psi is used with a booster providing whatever additional pressure is needed. When high flow rates at high pressures are needed, the booster can charge a receiver to an even higher-pressure level, thus storing a volume of gas available for rapid release at a constant pressure through a pressure reducing valve. Aerosol type gases (propane, CO2, nitrous oxide, halons, SF6, etc.) can be boosted as a liquid or gas in controlled applications.
Gas boosters make fiscal sense for those who:
Not only will a Haskel Gas Booster or packaged system allow you to use 90 to 95% of the gas in your purchased cylinders, but the system will maintain your process pressure when cylinder pressure drops to as low as 30 psig.
In times of abundant and inexpensive gas, industrial packagers would let physics do the work of the gas compressor by simply allowing the higher pressure of the supply bottle to pressurize the bottle to be filled. However, for this process to be useful, a significant amount of gas is left in the supply bottle. At today’s costs, this loss is unsustainable—industrial gas packagers must use every molecule of available gas.
Industrial gas companies have an important job ahead of them—ensuring availability of gases for a broad range of industrial applications while maintaining profit margins. Proper gas compression system design can help to increase both efficiency and output. In markets facing significantly increased demand, adding a second booster to the manufacturing line can reduce maintenance downtime and increase total output. Continued innovation in the development of gas boosting technology has helped to broaden the options for optimal gas compression system design.
One common scenario is the packaging of industrial gas from the ‘six pack’ of K bottles to smaller bottles. As volume demands increase and tube trailer delivery becomes more economical, system needs may change.
Gas booster system designs vary by application, inlet and outlet pressure, and flow rate. The purchase of the right gas booster is the most significant capital cost, but proper system design may require high pressure valves, fittings, and tubing to control, contain, and store these high-pressure gases for maximum efficiency. Haskel and its sister company BuTech offer a full suite of products to ensure the right fit to application.
Figure 2: An example gas booster system configuration for a typical transfer of gas from K-bottles to smaller bottles.
What’s the right booster technology for your application? Safety, reliability, and capital cost all play into total operating costs.
The primary drivers of gas booster system selection are your flow rates, outlet and inlet pressures. Those pressures can determine how many compression stages your system will require. Because of the compressibility of gas, the system should be designed to boost with a gas compression ratio (desired outlet pressure divided by the inlet pressure) of about a 5:1 or 6:1 ratio per stage for greatest efficiency. Keeping the gas compression ratio low will also help to reduce the outlet temperature of the gas, as the heat that is generated during the compression has more opportunity to disperse in a multi-stage compression system. With oxidizing gases such as oxygen, avoiding a high compression ratio keeps the temperature down, reducing the likelihood of a fire.
For an application that requires a gas to be boosted from 100psi to 2000psi, you would boost the gas in the first stage, for example, from 100psi to 500psi, and in a second stage, from 500psi-2000psi. A two-stage booster will automatically balance the pressures between the first and second stage and does not require operator intervention.
It is also important to use a booster with the largest displacement possible on the suction stroke from the gas supply. The more gas molecules the booster can draw in per stroke, the higher the flow rate it will generate.
While most of the Haskel boosters are suited to a range of industrial gases, some gases or applications dictate specific product lines for increased safety in handling. When handling oxygen, it’s particularly important to keep the gas compression ratio low.
Careful control over contaminants is another concern that impact safety and quality of your end product, especially for boosters used for oxygen or other gases in high purity applications. Haskel offers booster assembly and cleaning in Class 100 clean rooms, and arrives oxygen cleaned, certified and ready for use for handling oxygen or other gases used in high purity applications. Haskel recommends that the boosters used in applications requiring special cleaning, such as oxygen handling, be resealed, recleaned and recertified every three years. Haskel offers this service.
Noise is also an important consideration for employee safety. OSHA and state regulations, facility footprint, and manufacturing line set-up will have implications to system selection and set-up.
Maintenance and service needs, and unscheduled repairs, are an important consideration to total cost of ownership. Many modern gas compression systems include sensors and AI for proactive repair to reduce downtime.
In today’s environment, throughput is a more significant long-term concern than initial capital costs for industrial gas packaging companies. Bottom line: it’s about maximizing the amount of gas you’re able to compress, getting every last molecule, while balancing energy costs, footprint, and maintenance. Careful system design and selection can improve total output and help to meet the growing needs of customers while maintaining profit margins.