Can Your Autogas Pumps Effectively Address 3 Critical Challenges?
Pressure, viscosity and cavitation considerations, combined with strong global growth, make finding the best pumping technology a critical concern for Autogas retailers
By Thomas L. Stone
As Autogas continues to grow in popularity as a motor fuel around the world – currently ranking third in annual global consumption – its retailers must familiarise themselves with its storage and handling characteristics if they are to create an effective and efficient Autogas-dispensing business.
With this in mind, there are three critical challenges that must be addressed in order to optimise the Autogas-dispensing process. Let’s take a closer look at those challenges, and also illustrate the ways that a certain style of pumping technology – regenerative turbine – can be used to handle those challenges.
For questions on your specific Autogas handing application challenges, please contact Ebsray.
Autogas, which is a utilisation of LPG, is constructed of a propane-butane mixture. As such, it can be transported and stored as a liquid, but will vaporise and burn as a gas when not under pressure. This ability to easily change from a liquid to a gas state is a unique motor fuel property.
While the benefits of Autogas are obvious, as mentioned, there are three significant challenges that must be acknowledged, confronted and overcome when handling the fuel:
Due to its status as a liquefied gas, Autogas must be stored in an enclosed container under pressure. When in a pressurised container, the Autogas assumes the form of a liquid with any gas vapours that are present rising to the top of the storage vessel. These vapours create the pressure that keeps the liquid from boiling. Any upset in the equilibrium between the liquid and gas phases will cause the Autogas to boil off or vaporise. This means that the pressure must remain constant during storage.
When in a liquid state, Autogas has a viscosity of around 0.1 centipoise (cP), which makes it approximately 10 times thinner than water. With a viscosity that low, Autogas can become difficult to seal. Also, when handling thinner fluids there is a greater risk that pump slippage will occur during transfer operations, compromising flow rates.
If the pump’s inlet pressure falls below the vapour pressure during an Autogas-transfer operation, vapour bubbles will form in the Autogas. As the bubbles maneuver through the pumping chamber and the pressure increases, they will implode and cause cavitation. When cavitation occurs, it creates pressure spikes and results in increased noise, vibration and, if unchecked, damaged pumping-system components.
Over the years, two common types of pumps that have been utilised in Autogas-handling applications are centrifugal and side-channel pumps. However, both technologies have operational shortcomings that hamper their ability to handle Autogas safely, reliably and efficiently.
Centrifugal pumps are prone to experiencing vapour lock when handling Autogas. They are also not self-priming, unless submerged. But there are additional disadvantages when using submersible centrifugal pumps, a noteworthy one being that they must be degassed before maintenance can be performed on them, which is an elaborate, costly and time-consuming process.
Side-channel pumps are self-priming, but they are very poor for handling any fluids that contain solids, which can be found in lower grades of Autogas. They can also have a prohibitive purchase price and are expensive to maintain.
As an alternative to centrifugal and side-channel pumps, PSG®, a Dover company, Oakbrook Terrace, IL, USA, offers Ebsray® Regenerative Turbine Pumps, Cromer, Australia. For more than 75 years, Ebsray, acquired by PSG in 2013, has been a developer and supplier of industry-standard regenerative turbine pumps for use in the LPG markets of Europe, Asia and Australia.
Ebsray Regenerative Turbine Pumps stand out in Autogas-dispensing applications because they have been designed for use in high-pressure fluid-transfer applications. They feature an innovative impeller design that optimises hydraulic performance, resulting in high differential pressures even at low flow rates, a critical consideration for Autogas applications.
Ebsray regenerative turbine pumps are offered in various models and configurations that have been specifically developed for underground, aboveground and submersible Autogas installations and applications.
As Autogas continues to grow as an alternative motor fuel around the globe, determining which type of pumping technology to use at Autogas-dispensing facilities is becoming a front-of-mind concern for retailers. Ebsray’s Regenerative Turbine Pump technology has been proven to possess the operational characteristics that allow it to overcome the pressure, viscosity and cavitation challenges that are inherent in Autogas-handling operations.
About the Author:
Thomas L. Stone is the PSG® Director of Marketing based in Grand Rapids, MI, USA. He can be reached at firstname.lastname@example.org. For additional information on Ebsray’s regenerative turbine and positive displacement pump technologies, please visit ebsray.com or call +61 2 9905 0234. Ebsray is product brand of PSG®, Oakbrook Terrace, IL, USA, a Dover company. PSG is comprised of several of the world’s leading pump brands, including Abaque®, Almatec®, Blackmer®, Ebsray®, EnviroGear®, Finder, Griswold™, Mouvex®, Neptune™, Quattroflow™, RedScrew™ and Wilden®. You can find more information about PSG at psgdover.com.