The Ascent Continues to B50

Written on: July 9, 2023 by Paul J. Nazzaro

A collaborative effort from Clean Fuels, NORA, Clariant and AFS has led to the development of an additive solution that markedly improves B50 cold-flow performance.

At the Eastern Energy Exposition in Atlantic City, NJ, held in May, Bioheat® fuel enthusiasts came together to learn about yet another milestone achieved by a team under the leadership of Scott Fenwick, Technical Director for Clean Fuels Alliance America.

This latest achievement began approximately three years ago at a Clean Fuels planning session, where those responsible for further commercializing biodiesel utilization throughout heating-fuel markets decided on and committed to developing advanced cold-flow chemistry designed to provide Bioheat® fuel dealers with enhanced winter-weather performance in blends up to B50. Through a uniquely positioned, highly capable group of industry experts and professionals, the team developed and delivered advanced chemistry that has clearly demonstrated success in depressing B50 pour points (PP) down to between -40°F and -50°F and cold filter plugging points (CFPP) to -17°F.

I like analogizing these types of significant efforts and milestones with other notable achievements to demonstrate the importance of planning and executing critical assignments to help ensure that Bioheat® fuel continues to expand throughout the space-heating markets, which demand decarbonization today. For instance, the first recorded people to successfully reach the summit of Mount Everest were Tenzing Norgay and Sir Edmund Hillary on May 29, 1953. Mount Everest, the highest mountain on Earth with its peak reaching 29,032 feet above sea level, posed an awesome challenge—one accepted and conquered by the two adventurers.

Fast forward to 2023 and a collaboration between Clean Fuels, NORA and specialty chemical company Clariant, committed to creating innovative and sustainable solutions for customers from many industries. These visionary organizations came together to deliver a solution to the long-standing cold-flow concerns of liquid-fuel users desiring to use biodiesel for carbon mitigation today. Like Norgay and Hillary, who set out to accept the challenge and scale the mountain before them, and like our own industry’s adventurers, they ultimately did plant a flag at the top of their mountains—whether real or proverbial—as they raised the bar with a new strategy that delivers confidence when managing cold-flow challenges in outside oil tanks.

The cold-flow properties associated with higher blends like B50 pose a major hurdle for the home-heat sector in its pursuit to meet the legislative demands of decarbonization that lie before them. The sale and use of higher and higher blends of biodiesel in heating oil are not optional if success in decarbonization is to be realized. Biodiesel is integral to ultra-low sulfur heating oil (ULSHO) for reducing greenhouse-gas (GHG) emissions and offers a more sustainable alternative to carbon-based fuel oil. Soy methyl ester is the preferred blend component due to its high availability across the U.S. and its more desirable base cloud point of 32°F. However, all biodiesel feedstocks that meet ASTM D6751 are acceptable to create blends of Bioheat® fuel. The cold-flow properties of B50 blends are challenging, especially in areas that experience severe winter weather, and cold-flow additives must be one important part of a systemwide solution to overcome these obstacles.

Understanding what needed to be done, the team set out to develop an attractive solution for the U.S. heating-oil industry—one that would allow for a significant improvement in the cold-flow and storage properties of typical B50 blends and enable enhanced winter operability.

After careful planning with Clariant and NORA, Advanced Fuel Solutions (AFS) acted as the liaison between regional wholesale fuel-terminal operators and domestic biodiesel producers to secure representative samples of ULSHO, biodiesel and various existing additive solutions for this two-year evaluation process. The team ultimately created nine B50 blends to achieve a broad range of different qualities representing real-world supply availability.

Cold-flow improvers (CFI) are not new. They have been, and continue to be, used successfully in diesel fuel and heating oil to improve the winter operability of these fuels in their respective systems. It’s well known that, at temperatures below a fuel’s cloud point, both biodiesel and heating oil will form fatty acid methyl ester (FAME) crystals and paraffinic crystals, respectively, which will accumulate on the bottom of storage tanks. At the same time, the viscosity increases until the fuel stops flowing when its plugging point (PP) is reached. CFI technology modifies the crystal structure in a physical way to keep them small, allowing the fuel to continue flowing at lower temperatures. The properties favorably impacted by CFI technology include PP and CFPP only, as cloud point remains unaffected.

Under the leadership of Dr. Kerstin Mueller, the head of application development with Clariant’s refinery-services business, a comprehensive approach was used to address the challenges of enhancing the winter operability of B50 fuels. Without going into a “Bill Nye, the Science Guy” type of explanation, I will simply stick to the basics to help readers understand how the solution was realized.

Cold-flow additives are complex formulations of polymers with different functions. They start with base components that work with paraffin and FAME molecules in a co-crystallization process. Next up, a synergist is selected and added to help improve the performance of the base components; a synergist alone has no effect. The next component that brings it all together is the addition of an anti-settling agent, which assists in preventing agglomeration. Simply stated, this slows down diffusion times that keep particulate contamination suspended, allowing for continued flow of products inside the tank.

This study confirmed that CFI formulations can contain up to 10 different polymer components described above, but no single component alone improved operability until a combination of all three categories were blended. What we learned when we reached the top of the mountain was, as Aristotle first said, “The whole is greater than the sum of its parts.”

Once the formulation was deemed successful, Dr. Mueller continued to the next level of product development: Determining the robustness of the CFI solution. What exactly is robust testing? It starts with a series of testing that answers questions such as:

* Do water residues in B50 impair the PP and/or CFPP performances?
* Does water in B50 impair the cold-storage behavior?
* Does the new CFI perform in combination with other multifunctional heating-oil additives, such as performance packages and cloud-point depressants?
* Does the filterability of the heating oil change when it contains additives?
* Does the additive cause yellow-metal corrosion?

Using ASTM measurements, all tests generated passing results. The final product solution was selected based on its PP and cold-storage performances, handling and robustness. Now, with the formulation in hand and all the boxes successfully checked off, it was time for upscaling.

In November 2022, 560 pounds of the selected CFI solution were successfully manufactured, with additional volumes planned. These pilot batches were then shipped downstream to AFS to implement Phase I field evaluations.

To conduct these initial field evaluations, AFS worked with Hart Home Comfort, a B50 Bioheat® fuel distributor with comprehensive understanding of how high blends need to be stored, blended and distributed to their expansive customer base. Although these tests were limited in scope because of the time of year we asked for them, they revealed what we expected—deep depression of PPs over the course of two fuel drops, as well as acceptable sedimentation control.

Beyond this field test, AFS and NORA conducted comprehensive laboratory evaluations of various fuels and additive formulations against the newly developed CFI solution and documented an exceptional improvement in flow as well anticipated sedimentation management. More testing is expected late this summer through the fall and winter with expanded parties that now offer B50 to their customer bases.

As the team presented its journey and experiences in this product-development process to a packed house in Atlantic City, Fenwick followed Dr. Mueller’s remarks and reiterated the obvious: The new additive is one part of a broader picture.

Anyone in the liquid-fuels supply chain knows that water is its Achilles heel. Fenwick strongly encouraged those up and down the chain to pay close attention to the multiple touch points in the system—from ship, barge, terminal, delivery truck and home-heating tanks. Let’s face it, we must combat switch loading-deficient bulk-plant surveillance, waterborne fuel challenges and, of course, inadequate attention to oilheat tanks at homes. Oilheat providers must play an active role in this process, Fenwick added, recommending that they stick tanks, conduct periodic bottom sampling and analysis, and keep records of inbound loads of the fuel that is bought and sold. Make a commitment to get teams trained and stay committed to surveillance. One can’t rely solely on fuels meeting ASTM standards because they are minimum specifications. We can and should do better than the bare minimum.

The new additive I’ve discussed in this article is slated for release in winter 2024. Like those adventurers who scaled Mount Everest, this group of visionaries accomplished what many thought could not be done, and they haven’t stopped. Testing continues at NORA and other large molecule manufacturers to continue improving performance of these unique chemistries that will be one very important part of the overall solution designed to allow us to blend higher blends of low-carbon liquid fuels. ICM