The use of bio and other alternative fuels can create some handling issues throughout the distribution infrastructure and bulk plant and terminal operations are no different in this regard. Pre-blended product at lower concentrations should provide few issues. But some marketers are doing the blending themselves or using fuels with much higer concentrations. <i>NPN Magazine</i> spoke with Brian Savage, president of Savage Associates, for a rundown of the major concerns with the bulk plant storage and blending of biodiesel and Bioheat<tm> fuels. Founded in 1938 and headquartered in Berkeley Heights, N.J., Savage Associates internationally provides fueling infrastructure services to commercial, military and industrial customers.
NPN: How much interest are you seeing in marketers getting B100 and blending their own biodiesel or Bioheat<tm> mixture?
Savage: In some cases the fuel will already be blended by the time it arrives in a bulk plant, but marketers can make the business decision as long as the incentives work out properly to blend it themselves. To get going you would likely need a 20,000 gallon aboveground insulated tank, an immersion heater (if needed), auto controls, a recirculator, the supply line to the rack (4”), a 2” blending metering position for each position to get you from B1 to B 20 – a typical one like we just finished had four positions – and when you add things up including all the labor and concrete, you come out to about $500,000. We've probably put in about 21 facilities like this. However, you have Sun, and Sprague and Global blending at their racks and you can pick up a blended product for your own storage tanks and not spend that type of money. You have to have a large enough through-putting arrangement through your facility to actually spend that kind of money.
NPN: When considering biodiesel of Bioheat <tm> what are the major concerns a plant operator has to keep in mind?
Savage: Temperature, temperature, temperature. Temperature is one of your major influences and not just the temperature of the product, but the temperature of the product you’re blending it in with whether it's diesel fuel or heating oil. You have to follow some golden rules like never have a greater temperature differential than 20° F.
We had a driver say, “Wow, you should see this thing floating in my compartment.” And what it was, was the B100 going into a cold compartment in the wintertime, losing its temperature and pour point and becoming a gooey mass and then when he filled it with the No. 2 oil, it floated up. That's one of the things you run into. Golden rules. I don’t want to see any greater temperature differential in 20° F. You put hot B100 in your diesel fuel or No. 2 oil and the bacteria will love you. Two years ago we had an issue where a major supplier was loading product and blending B100 with No. 2 home heating oil at the rack and the temperature differential was between 40° F and 60° F and within two weeks over 80 accounts ran into out-of-service problems because of rapid growth of bacteria.
And I do not want to see sequential blending. With sequential blending the accuracy of your blend is going to be off and the temperature differential will be that much greater, but people still do it. They say, “I don't have any problems.” How do you know you don't have any problems?
NPN: What are some of the specifics for keeping that temperature differential in the 20° range?
Savage: Ideally you want to keep your B100 at around 70°F. The manufacturer might load it at 80° or 90°F by the time it reaches a plant that might be down to 70° or 80°F, but an insulated tank maintains that temperature and helps keep operating costs down. We heat trace and insulate all lines that are going to see B100 and follow that up with external thermostat controls. Sometimes you do not have to heat the whole line – just a section of the line – so you heat that section to minimize cost. And every single tank, above or below ground, will have a source of heat whether it's a heat exchanger or an immersion heater. Even if you live in an otherwise warm area, always provide for the worst-case scenario.
If you’re picking up a load of 7,700 gallons of B100 loaded hot at 90°F even with the standard trailer when it gets to the location a hundred miles away, it might have dropped in the dead of winter maybe 10°F to 15°F. So you get it into the insulated tank you may never have to use the immersion heater depending upon the rate of use. For example, in Philadelphia we did a couple of plants and last year one of them never had their immersion heater go on because they used it frequently enough that they were bringing in a trailer load every two days and it maintained the temperature. Now the product lines going out to the rack and the 2” blend lines were traced and insulated. And to save money further you want to make sure your immersion heaters are properly sized. And want them running in a 460V service for less power consumption.
NPN: In bulk storage scenarios, is there any need for additives beyond those typically used in other applications for the fuel?
Savage: Exotic additives are not required beyond those you would use for any other application of this product.
NPN: What are some of the other potential concerns you can have with biodiesel or Bioheat <tm> in colder climates?
Savage: If you're building an aboveground tank, your spill plan requires that the tank be secondarily contained. If you have a double-wall type of tank and you don't pay attention to your overfill alarms and you do get overfill into that compartment and it’s wintertime that material will become rather difficult to get out until it warms up.
NPN: What about the typical materials used in the plant infrastructure and biofuels? With ethanol, rubbers and plastics can be an issue, is there a problem with biodiesel or Bioheat <tm>?
Savage: With seals, we've been using Buna-N (nitrile) and Viton and we don’t have a problem.
NPN: Although not a biofuel, ultra low sulfur diesel/ heating is a relatively new product that is growing in use, often being blended with a biofuel. The Petroleum Equipment Institute has identified some potential corrosion issues with the product. What is your take on that and what needs to be done to minimize those concerns?
Savage: The biggest issue there seems to be keeping air out of the process, which can be exasperated if pumps run dry for more than 4 or 5 seconds unnecessarily. It's a similar situation with offloading ethanol—don't strip your pumps. Don't prime the pumps; don't let the meters run dry. Ultra low sulfur diesel does absorb moisture so remove all the cast iron from a system handling ultra low sulfur diesel. And B100 has no impact on ultra low sulfur corrosion.
NPN: Is there any issue with the different biodiesel/bioheat blendstocks, for example soybean vs. animal fats?
Savage: The pour point does change with different blend stocks, though, other issues related to metallurgy or seals cannot come into play.