The Catalyst That Refused To Die

April 22, 2015 |

Catalytic mobile unit 1Battelle-led group succeeds in US Department of Energy challenge — 1,000 hours of continuous biomass hydrotreating on a single catalyst charge.

The undefeated champ hits 1200 hours before being retired from the ring. Next stop, 4000 hours?

In Ohio, we hear from Battelle that they have succeeded at the United States Department of Energy challenge to demonstrate at least 1,000 hours of bio oil hydrotreatment on a single catalyst charge, while making commercially viable transportation fuels from biomass pyrolysis.

In a project that has just wound up and stems back to a 2011 DOE grant, Battelle (with partners Marathon Petroleum and the Pacific Northwest National Lab) hit the 1,200 operational hours mark, and achieved a yield of around 60 gallons of finished hydrocarbon fuel per dry ton of feedstock, in an end-to-end process.

Let’s put this in perspective. Based on a $55 per ton feedstock cost, that’s less than a dollar per gallon for the raw feedstock inputs, which is unheard of in the world of finished hydrocarbon fuels made from biomass.

The backstory on bio-oil

If you’re new to the story of pyrolysis, bio-oil and making a hydrocarbon fuel from biomass, here’s the need to know:

In pyrolysis, the biomass is cooked at high temperatures. Some processes are faster than others, some use a catalyst, some do not. The end result is a conversion of biomass to a combination of light gases and a heavy bio-oil, which has been called bio-crude in some quarters, but bio-oil has had its limitations. Specifically, it’s full of oxygen, which is very different from hydrocarbon fuels (which are, as the name suggests, made entirely of carbon and hydrogen), which make them corrosive and unstable.

Some advantages of the pyrolysis process: is that it uses the entire biomass, there’s no CO2 byproduct as with fermenation, there’s no need for costly enzymes or other exotic microorganisms to be developed, and the issues with scaling up fermentation are avoided.

Downsides? Several. One show-stopper: bio-oil cannot be used as a transportation fuel. However, it can be upgraded via a process known as hydrotreatment, which extracts the oxygen in a reaction with hydrogen that produces pure water as its byproduct. It’s a process used in the petrochemical industry, and it has been used successfully to remove excess oxygen from organic waste and vegetable oils to convert them into diesel and jet fuel.

The Achilles Heel

Rewind back to 2010. At the time, DOE saw that longevity of hydrotreatment catalysts was an Achilles’ heel for converting biomass pyrolysis oils to biofuels. Some promising catalysts could not deliver much more than 100 operational hours.  So a funding opportunity announcement issued from DOE in 2010, and in 2011 Battelle along with Marathon and PNNL won a grant and got to work: the challenge was a step-change for the industry, to reach the 1000 hour mark.

Marathon Petroleum Corporation provided Battelle with some support in the DOE program and helped in assessing the biofuel product. Scientists at PNNL developed bio oil stabilization catalysts for Battelle’s process.

John Holladay, Manager of the Biomass Sector at PNNL, noted, “This is how public-private partnerships are supposed to work and it couldn’t have happened without DOE’s support,” he said.

“We developed catalyst and hydrotreatment process, in which we take the biooil from our mobile unit,” Zia Abdullah, Institute Fellow at Battelle, who was Principal Investigator on the project, told the Digest. “Early this year we reported that we surpassed the program goal. We accomplished 1200 hours and at that time that we stopped the process, having achieved the milestone.”

Next steps

1200 hours is a step-change for the industry.  But 4000 hours is generally believed to be the target for a commercially process — that’s 6 months of operation on a single catalyst charge.

Battelle’s Abdullah observes, “We have made big step beyond the 100 hours seen before, and now one can easily envision how to get to 4000 hours, and then scaling up the process in parallel so that we match the output from our mobile pyrolysis unit.”

“Our next step is to scale up to larger reactor sizes, and we need to put more mileage on the catalyst. Can it do 2000, can it do 4000, even 8000 hours? 8000 would buy us us a full year in a commercial plant, one change annually. Our stretch goal for now is 4000 hours, and for now, we would like keep processing at small scale, to demonstrate that the catalyst can survive 4000 hours. Once we’ve reached that milestone, then we start scaling up, which we will be developing ideas for in parallel.

“Our hope is that we will start our project in 2015,” said Abdullah, “and we are looking at maybe 18-24 months, by which time we want to achieve 4000 hours and a have a reasonably good version of design that would be compatible with our mobile pyrolysis unit.”

So that takes us to about 2017.

Battelle’s Mobile Pyrolysis Unit

It was Battelle’s ton-per-day pilot system that supplied the bio oil for its DOE-funded hydrotreating project.

Battelle's hydrotreater

Battelle’s hydrotreater unit

Battelle engineers and scientists have developed a mobile device that transforms unwanted biomass materials such as wood chips or agricultural waste into valuable bio-oil using catalytic pyrolysis. As currently configured, the Battelle-funded unit converts one ton of pine chips, shavings and sawdust into as much as 130 gallons of wet bio-oil per day.

Scale. Battelle is evaluating this one-ton-per-day system at its West Jefferson, Ohio facility. The pilot-scale system is the culmination of Battelle’s second-stage development of the mobile pyrolysis technology. In the first stage, which took place over the past four years, Battelle created a bench-scale machine that converted 50-pounds of woody waste per day, demonstrating the novel concept. The next step will be to work with a strategic partner/investor to produce a tenth-scale demonstration unit.

Because of its small size, the pyrolysis unit is installed on the trailer of a flat-bed 18-wheel truck, making it mobile and thus transportable to the waste products. This feature makes it ideal to access the woody biomass that is often left stranded in agricultural regions, far away from industrial facilities. It’s potentially a significant cost advantage over competing processes represented by large facilities that require shipment of the biomass from its home site.

Feedstock. Currently, Battelle experts are using mainly pine waste in the transportable pyrolysis unit, although  the high-tech machine can be modified to use other types of unwanted agricultural field residue known as stranded biomass, including corn stover, switch grass and Miscanthus.

By-products. Additionally, all of the waste materials produced by the unit’s process—liquid, solid and gas—have been taken into account. The liquid waste stream is water that can be safely recycled or disposed of, the solid char contains inorganics that can be used in fertilizers and the venting gas is monitored for safety.

Markets. Battelle’s leadership is committed to biofuels but see the best near term market opportunities in biochemicals. “Biochemicals to enable biofuels,” said Drew Bond, Vice President for Technology Commercialization for Battelle’s Energy, Health and Environment business. “Simply put, that’s our strategy. And we’re not alone in this but I can say that we are quite far along thanks to the foresight of our leadership.”

An alternative use of Battelle’s bio-oil is its conversion to a bio-polyol that can be substituted in chemical manufacturing for polyols derived from petroleum. Battelle’s bio-polyols have been validated by a third-party polyurethane producer as a viable alternative.  And, late last year Battelle entered into a strategic partnership with Equinox Chemicals, a specialty chemical manufacturer. Together, they seek to use the platform pyrolysis technology for the production of biopolyols and biochemicals with applications in multiple, rapidly growing, high-value markets.

The Bottom Line

As Marty Toomajian, President of Battelle’s Energy, Health and Environment business, observed, “Energy security is all about energy supply diversity,” he said. “We have tremendous fossil reserves in our country that should not be taken for granted. But neither should we take our renewable resources for granted. That’s why our work at Battelle spans across both, with the goal to maximize our fossil and renewable resources.”

60 gallons per ton, with a mobile reactor that can be taken to the feedstock, instead of taking the feedstock to the reactor? And, a catalyst that lasts? That addresses three major risk areas realting to yield, processing cost and feedstock logistics — a step-change, indeed.

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