The ultimate goal of our research program here at China Lake is to create a full-performance JP-5/tactical biojet fuel that can be derived from a fully renewable and sustainable source of reduced carbon. Given recent advances in the conversion of starch and cellulosic biomass to biobutanol, we have initiated a program to explore using the C₄ alcohol as a pivotal and versatile starting point for the creation of new fuels. Because both butyl ether and 1-butene can be easily derived from 1-butanol, we are investigating use of these chemicals as precursors to biojet fuels that will meet the required energy content and key performance specifications of JP-5 jet fuel.

—Wright et al. (2008)

Cobalt Technologies had earlier outlined a product strategy for drop-in chemicals and fuels derived from its core n-butanol product. Dehydrating n-butanol can produce 1-Butene derivatives, says CEO Rick Wilson, which can then be relatively easily processed to hydrocarbon fuels: via alkylation to gasoline, or via oligomerization to jet fuel and diesel. (Earlier post.)

Under the CRADA, a team of scientists from Cobalt and the NAWCWD will investigate the optimum conditions for the conversion of n-biobutanol into jet fuel, while ensuring the process minimizes time, cost and energy consumption. More specifically, the combined team will optimize dehydration chemistry for the conversion of bio-n-butanol to 1-butene, followed by oligomerization of the biobutene into jet fuel, based on a process developed at NAWCWD.

Additional work will focus on converting the biobutanol into butyl ether, which the NAWCWD has shown can be mixed with n-butanol and other compounds to create a viable drop-in diesel fuel replacement.

We are pleased to collaborate with the US Navy to develop a renewable option for jet fuels. With our front end for producing renewable n-butanol and the NAWCWD’s technology for converting n-butanol into jet fuel, we can offer a complete process that directly addresses the military’s green fuels mandate.

—Rick Wilson, CEO of Cobalt Technologies

The US Navy has set a high priority on the development of cost-effective and sustainable domestic sources of fuels and has several initiatives in place to increase its use of biofuels, while decreasing its carbon-footprint and dependence on petroleum. By collaborating with the Navy scientists who have expertise in converting biobutanol to bio-jet and biodiesel fuels, Cobalt Technologies is well positioned to demonstrate and implement a large-scale process for generating sustainable and renewable fuel for both military and commercial use, the company said.

The CRADA with Cobalt Technologies is made possible by the US Federal Technology Transfer Act of 1986, which allows private organizations to access the expertise, capabilities and technologies of US Federal laboratories to improve the economic, environmental and social well-being of the United States.

Cobalt Technologies’ technology is based on a bacterial fermentation of lignocellulosic sugars into butanol. To convert the carbohydrates (cellulose and hemicellulose) in lignocellulosic biomass, Cobalt has developed a process that simultaneously extracts and converts the lignocellulosic materials into simple sugars. Cobalt’s approach integrates the extraction process with hydrolysis chemistry in a way that shortens residence time while maintaining mild conditions. This approach enables the use of smaller vessels and less expensive metallurgy, thereby minimizing capital and operating costs.

Cobalt production technologies are designed to process a broad range of feedstocks, reducing the risks associated with reliance on a single crop.

Cobalt has developed proprietary bacterial strain development technology for improving the fermentation performance of a variety of microbial strains. These strains are specifically selected for their ability to utilize all five of the sugars found in plant materials. This makes it possible to process a range of lignocellulosic biomass in the production of butanol.

Cobalt’s strain development technology has improved the economics of butanol production by increasing the rate, yield and concentration. This technology has also improved the resistance of the microorganism to the byproducts of biomass conversion. Thus Cobalt’s production technologies are designed to process a broad range of feedstock at high rates and yields, reducing the risks associated with reliance on a single crop.

Instead of a traditional batch process, Cobalt developed a continuous fermentation process. Continuous production increases the overall production time of the fermentation unit, reducing capital and operating costs.

Cobalt says that its continuous bioreactor system increases production rate as much as 11-fold over traditional batch fermentation processes, substantially reducing capital costs. The result is a more capital efficient production process, with lower input costs, resulting in a more economic process.

Historically, distillation—which is energy- and capital-intensive—has been used to purify butanol from petroleum and biological processes. Cobalt utilizes process and thermal integration to reduce costs. Cobalt’s distillation process for butanol recovery uses approximately half the energy and half the equipment services compared to conventional butanol distillation, the company says.

Resources

• Benjamin G. Harvey, Michael E. Wright, Roxanne L. Quintana (2008) The Oligomerization of 1-Butene; A New Approach to Full Performance Jet Fuels

• Michael E. Wright, Benjamin G. Harvey and Roxanne L. Quintana (2008) Highly Efficient Zirconium-Catalyzed Batch Conversion of 1-Butene: A New Route to Jet Fuels. Energy Fuels, 22 (5), pp 3299–3302 doi: 10.1021/ef800380b