All biodiesel plants require heat. While many facilities feature traditional boiler systems, alternatives do exist. Not all alternatives are appropriate for all plants, but producers electing to implement nontraditional heating systems can reduce fuel and maintenance costs and increase efficiency.
The specific alternative most appropriate for a given plant can be dependent upon a variety of factors, including plant size. Small plants may be able to eliminate the use of traditional boiler systems completely while larger plants may better be served by installing burner systems capable of handling more affordable alternative fuels. 

Development on innovative heating solutions will continue, but several unique heating systems are already in operation at plants across the U.S. In North Carolina, Patriot BioDiesel LLC has installed a system featuring ceramic elements that greatly improve safety by nearly eliminating the risk of methanol ignition. Alternatively, South Carolina-based Midlands Biofuels LLC has developed its own closed-loop recirculation system that provides on-demand heat to the system’s media. In addition, a variety of producers nationwide are utilizing an innovative burner system that allows waste glycerin, off-spec biodiesel and other waste materials to serve as the system’s primary source of fuel.

Innovative Heat Concepts LLC has developed a heating system that can increase operational safety at a plant while eliminating the risk of oil scorching. According to Chris Gupta, company owner, the technology features ceramic chip heating elements encapsulated by a composite of titanium powder and other materials. When an electrical current is applied to the elements, heat is produced. The system, called PTC Heating Technology, self-regulates based on fluid viscosity, Gupta says, which avoids the potential of scorching.

Patriot BioDiesel recently installed the ceramic heating system as part of a plant expansion. The PTC system has completely eliminated the need for a traditional boiler. According to Gabe Neeriemer, Patriot Bio-Diesel’s president, one clear benefit is that the high-efficiency elements detect media they’re in and adjust heat output. The elements also vastly reduce the risk of fire because they won’t ignite methanol vapors. 

Patriot BioDiesel has been operating the PTC system since December. “We are extremely happy with the system,” Neeriemer says. “The original reason I went to the heating elements was they would eliminate the need for a boiler,” adding boilers generally waste as much energy as they create.
In expanding, Patriot BioDiesel effectively doubled its production capacity but Neeriemer says the new ceramic heating system hasn’t resulted in significant increases in electricity use, and natural gas use has actually been reduced. Natural gas was used to warm the facility’s glycerin and vegetable oil, but during expansion Patriot BioDiesel installed heat exchangers to recapture heat, reducing its natural gas use.

Innovative Heat Concepts supplies PTC systems to a variety of customers, including those active in the biodiesel, algae and aquaculture sectors. “We are the sole supplier of PTC heater systems to Tactical Fabrication Co. in Dublin, Ga., for use in their biodiesel preheaters and reactors,” Gupta says. While some heat alteratives are most appropriate for plants of a certain size, Innovative Heat Concepts’ system can be custom-fabricated to accommodate any size plant, Gupta says, and the technology easily can be integrated at new or existing plants.

Neeriemer says Gupta’s company is designing new systems that specifically address biodiesel needs. He compares one innovation to a tankless water heater that can preheat vegetable oil as it enters the reactor. It’s essentially a continuous flow heat exchanger that uses the unique ceramic elements. Innovative Heat Solutions has also modified its technology in a similar fashion for use in methanol recovery.

While the efficiency of the system is certainly attractive, as are reduced plant maintenance needs, the safety benefits of ceramic heating elements are perhaps the most striking benefit. “If safety and heat efficiency is a concern, then our ceramic heating systems should be the first choice for a heating system,” Gupta says. “The inherent safety and consistent heating associated with our product is unmatched.”

Heating on Demand

Community-scale biodiesel producers often face a different set of challenges than their industrial counterparts. While traditional boiler systems may best suit many large-scale producers, the costs to purchase, install and maintain them may be difficult for small-scale producers to manage. To help mitigate those issues, Midlands Biofuels designed its own unique boiler-free heating system. According to Brandon Spence, facility co-owner and CEO, the system has been operating at his plant since mid-2008.

“We didn’t have the money to buy or install a large commercial boiler system that is used in most plants,” Spence says. “We’re also a small plant, so we didn’t necessarily need that size of a system.” To overcome those issues, Spence and plant co-owner, “Bio” Joe Renwick, began investigating exactly where heat was needed in the process and how that heat could be transferred and introduced into the plant. The result was the development of a small, modular, closed-loop circulation system that is fueled with natural gas. The system is very affordable—Spence estimates the total cost is about one-tenth the price of a standard boiler.

Similar to tankless water heaters, Midlands Biofuels’ system heats a water/glycol mixture present in its recirculative loop on demand and typically operates at 140 to 240 degrees Fahrenheit. “It’s got an expansion tank and a pump, and it delivers heat at whatever temperature we need it to at a certain point,” Spence says.

While Midlands Biofuels uses the system to generate all the heat its plant uses, including process heat, Spence notes it’s especially good for the pretreatment and preparation of waste oil feedstocks. According to Spence, Midlands Biofuels currently has two of these systems in operation under its ownership, and has also started building them for other biodiesel plants. In fact, two other producers are employing the system in their operations, either to provide full process heat to the facility or as a separate system for feedstock pretreatment.

The system takes up very little space within a plant and maintenance requirements are minimal. “You basically make sure the system remains full of fluid,” Spence notes. “It’s pretty much set it and forget it.” That said, Spence stresses the system wouldn’t be right for all producers. Rather, it’s most appropriately implemented by facilities with production capacities of 1 MMgy or less. “This is more for small producers,” he says. “It’s more manageable, less overhead and less work.”

Burning Better Fuel

Systems on the market also allow traditional boilers to be more flexible by burning alternative fuels. AgSolutions LLC has been doing business with the U.S. biodiesel industry since 2004. Its burner technology allows a boiler to be fueled with a significant portion of crude glycerin. Anthony Taylor, AgSolution president and owner, estimates that his company has supplied nearly 50 of its systems to the U.S. biodiesel industry over the past eight years.

Equipped to run on No. 2 fuel oil, the system can also take in low-quality vegetable oils, transmission fluid, used motor oil, or off-spec biodiesel as fuel. Depending on several factors, including glycerin quality and the burner’s specific design, the system can cofire these fuels with up to 75 percent crude glycerin. Taylor says the methanol content of the glycerin can range from 3 to 27 percent. 

 “What differentiates this from a standard No. 2 fuel oil burner or gas burner is we have to preheat the fuel to a high temperature, typically 180 to 200 degrees Fahrenheit,” Taylor says. “We also use a source of compressed air that pulls the fuel out of the nozzle and atomizes it into a fine particulate.” The atomization process allows the fuel to be heated to a lower temperature than would otherwise be required.

When you try to simply burn crude glycerin, you end up with issues because the flash point of the methanol is much lower, Taylor says. That means the methanol will burn first, and the glycerin will burn separately and produce a tremendous amount of ash. “By blending the glycerin-methanol blend with another fuel product—conventional or unconventional—you can basically bind it together and have a single combustion taking place,” Taylor explains. “No more precombustion of the methanol right out of the burner, and your final combustion is much cleaner, much more thorough and the ash is significantly reduced.”

Taylor is careful to point out the solution won’t be appropriate for all plants. “While most people are successful at it, there are others who will fail,” he says. “It’s not for everyone, and typically that has to do with the water content of the glycerin.” Glycerin with 6 percent water or less typically do well, Taylor says, adding that smaller systems without a separate small gas train in the burner can typically only handle a fuel mix that contains about 50 percent glycerin. The fuel mixture also has to be kept warm. Since the glycerin separates out from the fuel mix, it is also important that it’s continually mixed. It simply doesn’t make financial or operational sense to add those capabilities to some facilities, Taylor adds. He also says there’s more flexibility with the quality of glycerin as the size of the boiler system increases. “The larger the system,” Taylor says, “the larger the flame, the fewer issues you’ll have with higher water content in glycerin.”

Author: Erin Voegele
Associate Editor, Biodiesel Magazine
(701) 540-6986
evoegele@bbiinternational.com