PHASE SEPARATION
PHASE SEPARATION
Overcoming One of Fuel’s Greatest Quality Control Challenges with Economical and Simple Solutions
By Dwight Rutledge
WITH ETHANOL CONSUMPTION ON THE RISE IN CANADA, FUEL SITE OPERATORS NEED TO BE COGNIZANT ABOUT MAINTAINING A STRONG QUALITY ASSURANCE PROGRAM FOR ETHANOL BLENDS.
One of the considerations for a successful ethanol management program is preventing the distribution of an ethanol-blended fuel that has completed phase separation, which damages customers’ automotive engines. Here’s what fuel marketers need to know to keep their station’s reputation in good standing and customers happy.
Ethanol Is Becoming a Bigger Player
According to a 2018 Biofuels in Canada report, ethanol consumption in Canada increased from roughly 1.7 million liters in 2010 to 2.85 million liters in 2016, accounting for over six per cent of fuel consumption in the gasoline pool. Additionally, beginning in 2020, some Canadian provinces will increase the amount of ethanol content required in their fuel blends to an average of 10 per cent.
Ethanol blends offer many benefits including reduced dependence on imported crude oil and gasoline, reduced greenhouse gas emissions and lower costs to consumers. Unfortunately, ethanol blends are susceptible to phase separation, a potentially damaging fuel quality condition that occurs inside an underground storage tank when water contaminates an ethanol-blended gasoline. As such Canadian fuel site operators need to know how phase separation happens, the potentially devastating consequences of dispensing fuel that has completed phase separation and what they can do to prevent it from happening at their fuel site.
How Phase Separation Happens
Phase separation is a reaction that occurs inside the storage tank. When enough water mixes with ethanol-blended fuel in the tank, the ethanol absorbs the water molecules. This process creates water-saturated alcohol molecules that are too heavy to stay suspended in the gasoline solution and they fall to the bottom of the tank, causing the fuel being stored in the tank to separate into distinct layers. These layers include a gasoline layer at the top and an ethanol-water layer along the bottom of the tank. The upper layer lacks ethanol, and the lower layer is rich in ethanol. The absence of ethanol in the top layer lowers the octane number of the fuel and if it is dispensed into a vehicle, it may cause knocking in an engine. An engine can’t run on the ethanol-water layer. Unfortunately, the ethanol-water layer is usually right near the pump’s intake tube.
Phase separation is a process, with many factors influencing when the process occurs. That is to say, there are many variables that determine the actual point of separation. Water is the primary contributor to phase separation (without water, phase separation would not take place). Temperature is another key variable that influences the point at which phase separation takes place. Generally, as temperature of the fuel in the tank increases, more water is needed for phase separation to occur. The process is also influenced by other factors including:
Concentration of the alcohol in the fuel
Hydrocarbon content of the fuel
The presence of cosolvents in the fuel
Water is particularly problematic because it can enter the fuel supply in many points along the way from the refinery to the distributor:
Enters fuel system through condensation caused by humidity
Rain and surface water runoff enters system during fuel transfers
Water also frequently enters through pipes or vents, spill buckets or gaskets, or loose fittings
Maintenance and Prevention
With water being such a pervasive aspect of fuel management, establishing protocols for preventing the distribution of gasoline that has completed phase separation is essential to avoiding unnecessary mitigation costs, downtime and diminished customer loyalty.
However, maintaining a strong quality assurance program that prevents the distribution of bad gasoline can be especially challenging for independent and non-traditional fuel marketers (petroleum is not their primary business) in Canada. Unfortunately, preventive maintenance is sometimes deemed a lower priority than in-store sales strategies. Further, convenience stores that aren’t guided by a corporate program don’t always value best practices for fuel system maintenance.
For instance, phase separation can be detected in the tank utilizing special monitoring floats, sensors and tank gauges. However, some of these types of phase separation detection solutions are known to trigger false alarms that shut the pump down (which would prevent the system from dispensing bad fuel). Fuel site operators frustrated by the service disruptions sometimes disable the systems safety checks, which puts the operator at even greater risk of dispensing bad fuel.
Fuel dispenser filters represent a last line of defense against the distribution of gasoline that has completed phase separation. They are also a relatively economical solution. Special phase separation alert dispenser filters are engineered to detect and react to phase separation in ethanol-blended gasoline that passes through the filter. When fuel that has completed phase separation comes into contact with reactive chemicals in the dispenser filter, the filter’s super absorbent polymers expand to such a point that the flow through the filter becomes restricted. This slow flow prevents the bad fuel from being distributed and also alerts operators that there is a problem with the fueling system.
Conclusion
Fuel purchases seldom generate profits directly (in-store merchandise sales are the primary driver of c-store profits). But because fueling is one of the primary reasons why consumers stop at a c-store, fueling does have a significant indirect impact on a c-store’s overall bottom line.
According to a 2018 survey of convenience store customers, a c-store’s reputation is beginning to play a larger role in a consumer’s decision to fuel at a particular station. Weak dispenser filtration maintenance can lead to serious product quality crises that put customer loyalty at risk. Canadian c-store operators who have dispenser filters installed in their dispensers and who support a regular filter maintenance program, will help their c-store promote a positive customer experience. The bottom line is that the more customers who choose to fuel at your fuel site, the greater your c-store’s chances for profitability in both the long- and short-term.
Dwight Rutledge is business development manager at PetroClear, a Champion Laboratories brand dedicated to manufacturing fuel dispenser filters. He has more 35 years of experience in the petroleum-equipment industry.
