SF6 – A Greenhouse Gas
SF6 gas has been identified as the most potent greenhouse gas, surpassing others such as carbon dioxide and methane. Over the span of a 100-year period, SF6 is 22,800 times more effective at trapping infrared radiation than an equivalent amount of carbon dioxide (CO2). SF6 gas is also very stable, and it accumulates in the atmosphere in an essentially un-degraded state, thus having an atmospheric lifetime of 3,200 years. Therefore, even a small amount of SF6 can have a significant impact on global climate change. In 1997, the Kyoto Protocol (Global Warming Treaty) listed SF6 gas as one of the six greenhouse gases that should be controlled by reducing emissions or eliminating its use.
Despite regulations and efforts to decrease SF6 emissions, the amount of SF6 in the atmosphere has been steadily increasing worldwide since 1998. There are several uses for sulfur hexafluoride, but it is most commonly used as an insulating gas for electrical switchgear in the Transmission and Distribution of Power Industry.
SF6 gas is a man-made gas that does not naturally occur in large quantities. One major known source of underlying emissions is the production of virgin SF6. Virgin SF6 gas production was ceased in the United States with the greenhouse gas emission reduction targets instituted by the Environmental Protection Agency. Therefore, any virgin SF6 gas purchased in the United States is imported from Russia or Asia, where the gas is produced.
Comparing Emission Rates
The International Panel on Climate Change 2019 Guidelines for National Greenhouse Gas Inventories estimates that 0.03kg to 0.08kg of SF6 gas is emitted to the atmosphere per every 1kg (2.2lbs) of SF6 gas produced.
According to the Environmental Science & Technology Report, SF6 production in China contributed to 10 percent of SF6 gas emissions from the country between 1990 and 2010. In fact, producing virgin SF6 gas can create 12.5 or more times the emissions than reconditioning or recycling SF6 gas for re-use.
Comparison of Emission Rates for Virgin, Reconditioned and Recycled SF6 Gas
| Weight of SF6 Gas | Type of SF6 Gas | Emission dependent of process |
|---|---|---|
| 45.36kg (~100lbs) | Virgin SF6 Gas | 3.6kg (30lbs) to 36.3kg (80lbs) |
| 45.36kg (~100lbs) | Reconditioned (95% to =/>99.0% Purity) | =/<0.29kg(0.64lbs) |
| 45.36kg (~1,000lbs) | Recycled (97% Purity) | =/<0.12kg (0.05lbs)* |
*0.12kg (0.05lbs) emissions can be less and are dependent on handling processes and practices.
Recycled gas is defined as SF6 gas that has been filtered on-site via an SF6 gas cart. Depending on the quality of the SF6 gas recovered, it can be re-used as is, processed on site (recycled) via filtration, or be sent to a vendor like DILO for reconditioning.
Curbing SF6 Emissions by Sourcing Reconditioned SF6 Gas
SF6 gas can be reconditioned to a like-new state that meets or exceeds IEC standards even after being exposed to an arcing event or moisture and other contaminants. One way that we can curb emissions while using SF6 gas is to switch from purchased virgin gas to using reconditioned gas. There is a large, growing stockpile of SF6 gas already in circulation in North America. From an environmental perspective, reconditioning gas helps us to lower the carbon footprint by removing the need to produce more SF6 gas.
The reconditioning practice of SF6 ensures readily available supply for the power and utility sectors and eliminates the need and environmental impact importing virgin product from other continents. Any contaminants that may occur while SF6 gas is in use due to the intrusion of air, moisture, or generation of arc-byproducts, can be removed with the proper filtration and separation process.
An additional advantage for sourcing reconditioned SF6 is cost savings as virgin gas is typically costs double what reconditioned SF6 gas does. Technological advances in the filtration and separation process make it possible for reconditioned SF6 to meet/exceed federal and international industry standards, all at a lower cost. This cost savings does not compromise the quality of the gas.
Whether your SF6 supply is restocked with greater than 99 percent or “5/9 gas” (99.999 percent), the result is the same: electrical switchgear filled with a reliable medium that requires minimal maintenance. Using reconditioned SF6 has the added benefit of reduced cost, decreased lead times and increased reliability of supply during the extra challenges we face during this time of extended transport times the economic effects of Russia’s war in Ukraine.
Reconditioning Process
There are a few suppliers who can provide reconditioned gas at premium grades that exceed the standards for use in gas insulated equipment (GIE)set by CIGRE, IEEE, ASTM, and the IEC. Prior to the start of the reconditioning process, the contaminated SF6 gas is processed through an advanced pre-filter system to remove oil, moisture, and SF6 gas by-products.
The reconditioning process requires special equipment and handling procedures that ensure as close to zero emissions as possible. An SF6 gas separator uses a three-stage cryogenic process to recondition SF6 gas to a guaranteed 99 percent purity and less than 99.5 ppmV moisture.
DILO Certified SF6 Gas
Are you looking to source reconditioned SF6 gas? We can help! DILO Direct is the sole authorized service provider and dealer for DILO Certified SF6 Gas in North America. Our eco-friendly SF6 gas separators make it possible for us to recondition the gas to a refreshed state that exceeds the IEEE and IEC standards. It is a DILO guarantee that our SF6 never contains any by-products and is more than 99% pure, containing less than 99.5 ppmV moisture.
With the option to utilize DILO’s Certified SF6 Gas, there will be no requirement to purchase virgin SF6 in the future. DILO Direct serves as a one-stop shop for SF6 gas supply and gas handling services. We will have the SF6 gas picked up from your facility, recondition it to meet or exceed IEC standards, and return it to you in certified cylinders.
Do you have questions or would like more information? We are happy to help! Please contact us.
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