The diesel exhaust fluid market creates opportunities for pump manufacturers.
Growth and innovation in industrial pump design and operation are often driven by outside forces. A common force is the creation of a new market. A recent example relating to new opportunities for transfer pumps was the U.S. Environmental Protection Agency’s (EPA) announcement of tougher emission-control standards for on-road vehicles would be phased in from 2007 to 2010.
Specifically, all new, on-road vehicles must meet a tailpipe-emission standard of 0.2 grams of nitrogen oxide (NOx) per brake horsepower-hour (g/bhp-hr). This is a huge reduction in NOx and particulate matter that can be legally emitted into the atmosphere, especially considering that the standard in 1994 was 5.0 g/bhp-hr in 1994 and remained at 1.2 g/bhp-hr as recently as 2007.
When the manufacturers of diesel-powered vehicles looked for ways to make their vehicles compliant with these new regulations, they turned to Europe, where similar measures had been in place since the early 1990s. One of the most popular ways to control NOx emissions on European diesel vehicles was through the use of diesel exhaust fluid (DEF), originally known in Europe as aqueous urea solution 32 (AUS 32), which is a urea-based chemical reactant consisting of 32.5 percent urea and 67.5 percent deionized water that is injected into the vehicle’s exhaust stream. The most common process for this injection is called selective catalytic reduction (SCR), in which the exhaust is turned into harmless nitrogen and water vapor. This commitment to the injection of DEF—which has been called the largest addition to the motor-vehicle liquids marketplace in decades—and its role in the SCR process as the main way for diesel-powered vehicles to meet the EPA’s regulations has opened a new market in the U.S. Though estimates vary, it is safe to say that the amount of DEF that will be consumed in the U.S. by the year 2014 will be between 300 million and 600 million gallons annually.
With the advent of this new market comes the creation of a new supply chain, one that must be populated with enough DEF to keep every diesel-powered vehicle on the road compliant with the EPA’s mandate. This article discusses how advances in DEF-handling pumping technology and its use at critical points along the supply chain will help optimize the availability of DEF to end users who rely on it to keep their diesel-powered fleets compliant.
The Challenges of Moving DEF
When new motor-vehicle liquid enters the marketplace, the companies that develop equipment to produce and handle it must identify the liquid’s characteristics. DEF has a number of unique characteristics to consider:
- Because of its water content, DEF freezes below 12 degrees F (-11 degrees C), meaning it must be protected from extreme cold during storage.
- When DEF freezes, it goes from a liquid state directly to a solid with no intermediate “slushiness” stage.
- DEF can freeze and thaw with no resulting degradation of the urea solution.
- It is stable at storage temperatures up to 84 degrees F (29 degrees C). Exposing DEF to heat above 90 degrees F (32 degrees C) will decrease its useable shelf life.
- When exposed to air, the water in DEF evaporates and produces crystallized urea, which can harm the vehicle’s SCR unit and any transfer or pump components.
- DEF must not become contaminated during its handling. If it does, the SCR system can be compromised, which could lead to problems such as engine failure.
For pump manufacturers, the most important of DEF’s characteristics is its incompatibility with a number of materials that are commonly used in the automotive liquid supply chain—such as aluminum, bronze, carbon steel, copper, iron, nickel and zinc. However, stainless steel, polytetrafluoroethylene (PTFE), fluorocarbon and composite plastics such as polyethylene or PVC are compatible with DEF’s corrosive properties.
Another major consideration for the DEF-handling pump manufacturers is becoming familiar with the points along the supply chain at which pumping equipment is necessary. As the U.S. DEF market grows and matures, the production and supply processes and the roles of pumps in them, are becoming more well-defined:
- Tanker trucks and railcars deliver urea and deionzied water to chemical plants where the components are blended to create DEF.
- The newly produced DEF is transported by truck or railcar to a terminal storage facility.
- At the storage terminal, the DEF is pumped into packages, generally some combination of 330-gallon intermediate bulk container (IBC) tote, 55-gallon drums and two-gallon bottles.
- These packages are delivered to retail fueling centers, automotive-product retailers and maintenance-repair shops.
- In some cases, DEF is transported via tanker truck to retail fueling sites (most commonly at large truck stops) where it is transferred into DEF dispensers that are similar to gasoline/diesel pumps and is available for purchase by the public.
Optimizing DEF Handling
Two crucial pressure points in the supply chain for transfer pumps are from the production plant to the storage terminal and when the DEF is transferred at the terminal location into packages. To aid the DEF producer, transporter and packager, a series of positive displacement sliding vane pumps has been created that not only meets DEF’s product-handling needs but has also been designed to be materially compatible with its corrosive nature. Additionally, they offer energy-efficient operation that will help keep energy costs under control.
These pumps are also designed and manufactured to meet ISO standard 22241-3:2008, “Diesel Engines: NOx reduction agent AUS32.” They will meet or exceed that specification, which includes recommended and not recommended materials of construction. The 22241-3:2008 standard also communicates the level of cleanliness for wetted surfaces that contact DEF during the transfer process to avoid contamination.
When DEF is taken from the production plant to the storage terminal, it is generally by railcar, which can transport from 10,000 to 15,000 gallons (37,854-56,781 liters) of DEF, or transport truck, which can carry loads ranging from 6,000 to 8,000 gallons (22,713-30,283 liters). At the terminal, the DEF must be offloaded quickly, at rates up to 250 gallons per minute (947 liters per minute).
The 3-inch pump can deliver flow rates up to 250 gallons per minute at speeds of 800 rpm and differential pressures up to 125 psi (8.6 bar). This means that a 6,000-gallon transport truck can be unloaded in as little as 24 minutes. The pump’s sliding-vane operation also makes it better for these types of applications than centrifugal-pump technology because the design allows it to easily prime and pull a vacuum, which centrifugal pumps have a harder time doing, especially when dealing with piping configurations that have a restricted inlet or long runs. The pump is also constructed of stainless steel.
When considering DEF transfer from storage tanks into IBC totes, drums and jugs, one series of sliding vane pumps with no pushrods can run at speeds up to 1,200 rpm and can deliver flow rates from 49 to 92 gallons per minute (186-348 liters per minute). Some diesel haulers are also dedicating a storage compartment on their straight delivery trucks for DEF and mounting pumps on them so that they can deliver a load of DEF to a fueling site when they make a fuel delivery.
Another pump for the DEF-handling market is a 2-inch pump that will be similar to the 3-inch, with one notable exception: it is designed with pushrods so that it can run at slower speeds, making it ideal for package-filling operations that require flow rates between 25 and 30 gallons per minute (95 to 114 liters per minute). The design of the pump also means that it can be used with higher-viscosity fluids, which opens it up for use in other non-DEF markets.
All the DEF pump models can be powered by a base-mounted electric drive, diesel motor, truck-mounted power take-off (PTO) or hydraulic drive, and they are equipped with a double-ended, straight-keyed drive shaft that allows either clockwise or counterclockwise rotation.
A Look to the Future
Though the exact size of the DEF market in the U.S. in future years is impossible to predict, there’s no question that the EPA’s emission-control regulations, combined with most diesel-vehicle manufacturers choosing SCR as the best way to satisfy those regulations, leave no doubt that the DEF market will continue to grow. Playing a pivotal role in this growth are the pumps that will be used to deliver raw materials, transfer finished products to storage locations and fill packages for eventual use by the end user.
Recognizing the potential in this new market, pumps that are needed at all points in the DEF production-and-supply chain. The qualities of the sliding-vane operating principle help create transfer pumps that are not only compatible with DEF’s unique characteristics but able to operate in a way that is both energy-efficient and cost-effective for the end user.
Pumps & Systems, February 2012
