Purdue process converts lignin in intact biomass to hydrocarbons for chemicals and fuels

18 December 2014

A team of researchers from Purdue University’s Center for Direct Catalytic Conversion of Biomass to Biofuels, or C3Bio, has developed a process that uses a bimetallic Zn/Pd/C catalyst to convert lignin in intact lignocellulosic biomass directly into two methoxyphenol products (phenols are a class of aromatic hydrocarbon compounds used in perfumes and flavorings) leaving behind the carbohydrates as a solid residue.

Lignin-derived methoxyphenols can be further deoxygenated to propylcyclohexane—a cycloalkane. Cycloalkanes are important components of not only traditional vehicle fuels such as gasoline and diesel, but also jet fuels, such as Jet-A/Jet-A1/JP-8.

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The leftover carbohydrate residue is hydrolyzed by cellulases to give glucose in 95% yield, which is comparable to lignin-free cellulose.

In addition, the hemicellulose fraction of the biomass is hydrolyzed in the same step of lignin conversion, with easy separation of the resultant xylose. That xylose fraction can be selectively dehydrated to furfural and subsequently to other furfural-based chemicals or fuels in a biorefinery.

Mahdi Abu-Omar, the R.B. Wetherill Professor of Chemistry and Professor of Chemical Engineering and associate director of C3Bio, led the team.

We are able to take lignin—which most biorefineries consider waste to be burned for its heat—and turn it into high-value molecules that have applications in fragrance, flavoring and high-octane jet fuels. We can do this while simultaneously producing from the biomass lignin-free cellulose, which is the basis of ethanol and other liquid fuels. We do all of this in a one-step process.

Plant biomass is made up primarily of lignin and cellulose, a long chain of sugar molecules that is the bulk material of plant cell walls. In standard production of ethanol, enzymes are used to break down the biomass and release sugars. Yeast then feast on the sugars and create ethanol.

Lignin acts as a physical barrier that makes it difficult to extract sugars from biomass and acts as a chemical barrier that poisons the enzymes. Many refining processes include harsh pretreatment steps to break down and remove lignin, Abu-Omar said.

Lignin is far more than just a tough barrier preventing us from getting the good stuff out of biomass, and we need to look at the problem differently. While lignin accounts for approximately 25% of the biomass by weight, it accounts for approximately 37% of the carbon in biomass. As a carbon source lignin can be very valuable, we just need a way to tap into it without jeopardizing the sugars we need for biofuels.

The process starts with untreated chipped and milled wood from sustainable poplar, eucalyptus or birch trees. The catalyst is added to initiate and speed the desired chemical reactions, but is not consumed by them and can be recycled and used again. A solvent is added to the mix to help dissolve and loosen up the materials. The mixture is contained in a pressurized reactor and heated for several hours.

The team also developed an additional process that uses another catalyst to convert the two phenol products into the high-octane (RON 100) hydrocarbon fuel suitable for use as drop-in gasoline.

The processes and resulting products are detailed in a paper published online in the RSC journal Green Chemistry. The US Department of Energy funded the research.

In addition to Abu-Omar, co-authors include Trenton Parsell, a visiting scholar in the Department of Chemistry; chemical engineering graduate students Sara Yohe, John Degenstein, Emre Gencer, and Harshavardhan Choudhari; chemistry graduate students Ian Klein, Tiffany Jarrell, and Matt Hurt; agricultural and biological engineering graduate student Barron Hewetson; Jeong Im Kim, associate research scientist in biochemistry; Basudeb Saha, associate research scientist in chemistry; Richard Meilan, professor of forestry and natural resources; Nathan Mosier, associate professor of agricultural and biological engineering; Fabio Ribeiro, the R. Norris and Eleanor Shreve Professor of Chemical Engineering; W. Nicholas Delgass, the Maxine S. Nichols Emeritus Professor of Chemical Engineering; Clint Chapple, the head and distinguished professor of biochemistry; Hilkka I. Kenttamaa, professor of chemistry; and Rakesh Agrawal, the Winthrop E. Stone Distinguished Professor of Chemical Engineering.

The catalyst is expensive, and the team plans to further study efficient ways to recycle it, along with ways to scale up the entire process, Abu-Omar said.

The US Department of Energy-funded C3Bio center is an Energy Frontier Research Center. It is part of Discovery Park’s Energy Center and the Bindley Bioscience Center at Purdue.

Purdue Research Foundation has filed patent applications and launched a startup company, Spero Energy, which was founded by Abu-Omar to commercialize the process.

Resources

• Trenton Parsell, Sara Yohe, John Degenstein, Tiffany Jarrell, Ian Klein, Emre Gencer, Barron Hewetson, Matt Hurt, Jeong Im Kim, Harshavardhan Choudhari, Basudeb Saha, Richard Meilan, Nathan Mosier, Fabio Ribeiro, W. Nicholas Delgass, Clint Chapple, Hilkka I. Kenttämaa, Rakesh Agrawal and Mahdi M. Abu-Omar (2015) “A synergistic biorefinery based on catalytic conversion of lignin prior to cellulose starting from lignocellulosic biomass,” Green Chemistry doi: 10.1039/C4GC01911C

• Zemin Tian, Yingjia Zhang, Feiyu Yang, Lun Pan, Xue Jiang, and Zuohua Huang (2014) “Comparative Study of Experimental and Modeling Autoignition of Cyclohexane, Ethylcyclohexane, and n-Propylcyclohexane” Energy Fuels 2014 28 (11), 7159-7167 doi: 10.1021/ef501389f

UMTRI analysis finds distance driven per GDP has been decreasing steadily since early 1990s

18 December 2014

The sixth in a series of reports on peak motorization in the US by Dr. Michael Sivak at the University of Michigan Transportation Research Institute (UMTRI) finds that distance driven per GDP reached its highest values in a broad plateau from the early 1970s through the early 1990s, and then decreased steadily. By 2012, the value of this measure decreased by 22% from its absolute maximum, which was reached in 1977.

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Sivak suggests that some of the factors that likely contributed to the recent decline in the value of this measure are the decreased amount of personal transportation; decreased contribution to GDP of truck transportation; and the increased contribution to GDP of data services, information processing, and e-commerce.

The amount of fuel consumed per GDP peaked in the early 1970s, and then decreased by 47% by 2012. The relatively steep decline in the value of this measure reflects the added contribution of the improvement in vehicle fuel economy from the 1970s on.

In the previous five reports in this series, I examined recent changes in the number of registered light-duty vehicles (cars, SUVs, pickups, and vans), and the corresponding changes in distance driven and fuel consumed. The units of the analyses were both the absolute numbers and the rates per person, per driver, per household, and (where appropriate) per vehicle. The main finding of those reports was that the respective rates all reached their maxima around 2004. I argued that, because the onsets of the reductions in these rates preceded the onset of the recession (in 2008), the reductions in these rates likely reflect fundamental, noneconomic changes in society. Therefore, these maxima have a reasonable chance of being long-term peaks as well.

The present report examines the relationship between road transportation and economic activity since the end of the Second World War. The two measures of interest were distance driven per inflation-adjusted GDP and fuel consumed per inflation-adjusted GDP.

Resources

• Michael Sivak (2014) “Has Motorization in the US Peaked? Part 6: Relationship between Road Transportation and Economic Activity” (UMTRI-2014-36)

European automotive and automotive battery industries call for extension of the exemption of lead-based batteries from the EU ELV Directive

18 December 2014

The EU must continue to allow the use of lead-based batteries in vehicles as they are essential for the needs of future generations of European cars, according to the automotive and automotive battery industries in Europe. Lead battery and car manufacturers have requested that the current exemption for lead-based batteries within the ELV Directive’s wider ban on lead in light-duty vehicles is maintained for at least another eight years.

The comments are part of the formal submission made by the industry group to EU regulators who concluded the public consultation phase of the review of the End of Life Vehicle (ELV) Directive this week. Following the consultation the Commission is expected to release its opinion in the first half of 2015.

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The recommendation by EUROBAT, the European, Japanese and Korean car industry associations (ACEA – JAMA – KAMA) and the International Lead Association (ILA), is backed by a series of studies on the technical benefits of lead-based batteries and their sustainability, which includes their 99% recycling rate in Europe and the general availability of the natural resources used to make up the battery.

Part of the evidence submitted to the EU Commission is a study—A Review of Battery Technologies for Automotive Applications—which found that there are at present no alternatives, either technically or economically, to lead-based batteries for the SLI (Starting – Lighting – Ignition) function in vehicles. This means lead-based batteries are essential in virtually all conventional ICE (internal combustion engine) vehicles, hybrid vehicles (mild, micro and Plug-in-HEV, PHEV) and full electric vehicles.

All hybrid, plug-in hybrid and full electric vehicles equipped with high-voltage, advanced rechargeable battery systems also utilize a second electrical system on 12V level for controls, comfort features, redundancy and safety features. This electrical system is in all cases supplied by a 12V lead-based battery, the groups said.

The study also concludes that lead-based batteries will remain the only viable mass market energy storage system in automotive applications for the foreseeable future. Their low cost and unparalleled ability to start a car engine at cold temperatures sets them apart in conventional and basic micro-hybrid vehicles, and as auxiliary batteries in all other automotive applications.

Three additional studies also highlight the positive sustainability and environmental credentials of lead-based batteries that are an excellent example of the EU circular economy in action. The studies show:

• At the end-of-life, lead-based batteries have a 99% collection and recycling rate in a closed loop system, making lead-based batteries the most recycled consumer products in the EU.

• Using lead batteries in start-stop or micro-hybrid systems can result in emission savings of between 700-1600 kg CO₂ equivalent over a vehicle’s lifetime.

• The high recycling rate means that the environmental impacts of lead-based batteries, compared to the overall environmental impact of a vehicle, is negligible.

• There are no current or future resource availability issues with metals used in lead-based batteries.

The review. A Review of Battery Technologies for Automotive Applications assessed in depth the performance profiles of the automobile battery technologies currently in use:

1. Conventional vehicles, including start-stop and basic micro-hybrid vehicles are equipped with a 12V lead-based battery, which is required to start the engine and supply the complete electrical system, and can also be expected to provide start-stop functionality, as well as the entry class of braking recuperation and passive boosting.

   Due to their excellent cold-cranking ability, durability and low cost, 12V lead-based batteries remain the only battery technology tested for the mass market that satisfies the technical requirements for these vehicles. This is expected to be the situation for the foreseeable future.

2. Hybrid vehicles, including advanced micro-hybrid, mild-hybrid and full-hybrid vehicles rely on the battery to play a more active role, with the energy stored from braking used to boost the vehicle’s acceleration. In full-hybrid vehicles, the stored energy is also used for a certain range of electric driving.

   Several battery technologies are able to provide these functions in different combinations, with nickel-metal hydride and lithium-ion batteries coping best as requirements increase, due to their fast recharge, good discharge performance and life endurance. At high voltages, lead-based batteries are so far limited by their more modest recharge and discharge power and capacity turnover.

3. In plug-in hybrid and full electric vehicles, high voltage battery systems (up to 100 kWh for commercial vehicles) are installed to provide significant levels of electric propulsion.

   Lithium-ion battery systems remain the only commercially available battery technology capable of meeting requirement for passenger cars according to EV driving range and time, due to their high energy density, low weight, good recharge capability and energy efficiency. Other battery technologies (nickel-metal hydride, lead-based etc.) cannot deliver the required level of performance for these applications at a competitive weight.

   For commercial applications, harsh environments and heavy duty vehicles, high-temperature sodium nickel chloride batteries are a competitive option.

EUROBAT, the Association of European Automotive and Industrial Battery Manufacturers, acts as a unified voice in promoting the interests of the European automotive, industrial and special battery industries of all battery chemistries. Its more than 40 members represent more than 90% of the automotive and industrial battery industry in Europe.

Toshiba supplies Li-ion traction energy storage system for Tobu Railway

18 December 2014

Toshiba Corporation has supplied a Li-ion battery traction energy storage system (TESS) to Tobu Railway Co., Ltd. TESS stores traction energy generated by decelerating trains as they enter a station and releases it as needed when trains accelerate from the station. The system is planned to operate from 22 December.

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Toshiba’s TESS is installed at Unga station on the Tobu Urban Park Line, and utilizes Toshiba’s SCiB rechargeable Li-ion batteries to store regenerated power. SCiB offers a high degree of safety, a wide state-of-charge (SOC) range and stable operation at low temperatures. Toshiba’s calculates that its TESS offers a battery capacity ten times that of typical traction energy storage systems. The SCiB system also employs the company’s proprietary charge-discharge control technology, which takes full advantage of the wide SOC range of the SCiB cells.

The TESS system has rated output of 1000 kW; capacity is 387 kWh. Rated Voltage at the vehicle contact line is 1500 V; rated voltage at the battery is 607 V.

At Unga Station, regenerative traction energy from train deceleration is stored in the TESS for supply as needed when trains are accelerating from the station, facilitating stable electricity supply.

In addition to supporting stable supply, the system can also be optimally configured to support other applications, including traction energy loss prevention and peak demand power management.

Going forward, Toshiba intends to proactively expand marketing of traction energy storage systems and other products that facilitate efficient energy use of energy, to railway companies in Japan and overseas.