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Merica Acquires Majority Stake in Choren

Today it was announced that my new company, Merica International, has acquired Shell’s stake in Choren Industries. This is something we have been actively pursuing for some time. This transaction gives Merica a great deal more flexibility than we had previously.

The primary reason for the acquisition is that it gives us freedom to pursue the projects we want to pursue. While I have the greatest respect for Shell, our interests obviously would not always align with theirs. We are first and foremost a bioenergy company, and that is not their core business.

Further, if Choren wanted to make any major capital expenditures, it hinged on getting Shell’s agreement. As Shell is in a major cost-cutting mode, a lot of the projects we want to pursue could have been potentially impacted. Shell Fischer-Tropsch technology will still be used in Choren’s Freiberg BTL facility, but future decision-making will be simplified.

Here are excerpts of the story from Reuters:

Shell sells stake in German biofuel firm Choren

HAMBURG, Nov 5 (Reuters) – Oil major Royal Dutch Shell has sold its shareholding in German second-generation biofuels company Choren, Choren said on Thursday.

Choren is building Germany’s first biofuels plant using new generations of non-food raw materials as feedstock and is likely to start initial commercial production in 2010.

Shell had sold its minority shareholding to other shareholders which comprise German vehicles groups Volkswagen and Daimler plus a consortium of investors largely from the Hamburg region, Choren said in a statement.

Merica is within that “consortium of investors”, and is in fact the majority shareholder of the company now.

November 6, 2009 Posted by | btl, Choren, Merica, Shell | 16 Comments

Energy Potpourri

I am at the 2009 Gasification Technologies Conference this week, with a pretty full schedule. But there are three stories that I wanted to quickly hit. One is a follow-up on the previous cellulosic ethanol post, one is about Paul Sankey’s new report on peak demand, and the last is on a technology that ExxonMobil has reported on here at the conference that I felt was quite interesting. There will probably be no more new posts from me until the weekend. I only got away with this one because I decided to write instead of network (which I hate to do anyway) during free periods today.

When Technologies Are Mandated

I don’t care too much for mandates. I think they are so much worse than subsidies, because with a mandate you are really saying that it doesn’t matter how much it costs, you don’t want to know how much it costs – just do it.

If the government thought it was a good idea to blend bio-butanol into the gas supply, they could offer a $0.50/gallon subsidy to do so. If that doesn’t result in butanol entering the fuel supply, then that’s a pretty good indication that butanol is at more than a $0.50/gal disadvantage to gasoline. But imagine instead that it is mandated. The costs could go very high in that case, but gasoline blenders would still have to pay up. We may find out that the cost to fuel suppliers was $8.00/gal. Had it been a subsidy instead – and it needed to go to $4 or $5/gal to make it economical – it would have never passed because the costs would be more transparent.

Thus, I was not too enthusiastic about the cellulosic ethanol mandates we got as part of the 2007 RFS. In 2010, for instance, it is mandated that 100 million gallons of advanced biofuels will be blended into the fuel supply. Cellulosic ethanol has been the technology that has been favored, but I have warned about costs that are going to be very high. Instead of a mandate, suppose we put a $1/gal subsidy in for cellulosic ethanol. Then instead of relying on people promising that they can make cellulosic ethanol for $1/gal if they can just get grants, mandates, and loan guarantees – you put the burden on the producer. Here is a $1/gal subsidy for you. Build the plant, make your $1/gal ethanol, and collect the subsidy.

Not surprisingly we are now getting news that despite throwing a lot of money at it, the 2010 levels of cellulosic ethanol are going to fall far short of the mandate – as I have been saying all along. They are going to need more money to meet future mandates – highlighting the problems I have with mandates. From the NYT:

Biofuels Producers Warn They Are Going to Fall Far Short of Federal Mandates

“The current economic climate almost makes the RFS a moot point for the time being,” said Matt Carr, policy director for the Biotechnology Industry Organization.

His organization estimated last month that 2010 volumes will, optimistically, reach 12 million gallons, far short of the 100-million-gallon mandate that year.

Range Fuels had gotten an initial $76 million from the DOE, then an $80 loan guarantee from the USDA. They also got $100 million in private equity. (I predict some folks are going to lose some money – including taxpayers). But that still wasn’t enough, so they went back to the DOE for more money. This time, the DOE said no:

The Department of Energy’s loan guarantee program, producers say, has been particularly flawed. No advanced biofuel makers, aside from a partnership between BP PLC and Verenium Corp., have so far won approvals.

“We received a ‘Sorry, Charlie’ letter,” said Bill Schafer, a senior vice president of Range Fuels Inc., which is now building a cellulosic facility in Soperton, Ga., slated for completion early next year.

He said that under the program, biofuels companies must compete directly against solar, wind and even compressed natural gas — all energy technologies that, unlike advanced biofuels, have already been built at commercial scale.

So there you have it. The DOE seems to be losing some of the earlier enthusiasm for cellulosic ethanol. Range Fuels is here at the conference, by the way. I should probably say hi.

Again, this highlights the risk of mandates. Costs can spiral out of control. The ultimate cost can’t be easily predicted. Instead of assuming that technology can be mandated if enough money is thrown at it, we would all have been better off had there merely been subsidies offered. In that case, if this is truly not economically viable, the taxpayer may not have to foot the bill for millions of dollars for failed or stalled plants.

Printing Money

One of the reasons I invest in oil companies is that I think oil prices will continue to spike higher in the future. Because of the recession, we currently find ourselves with excess production capacity. But it looks to me like that excess production capacity will be eroded in the future, which will once again put pressure on prices. Oil companies will again reap very big profits by supplying a dwindling resource. (Whether governments will aggressively move to confiscate these profits is another question entirely).

There is another view that the oil companies will die out as oil depletes, and therefore oil stocks are very risky investments in the longer term. I don’t subscribe to this view because I believe the oil companies will possess enough cash to enter into any future energy business that looks lucrative. If we are supplying 90% of the cars with liquid fuels derived from coal in 20 years, I suspect it will be the oil companies producing it. In fact, most major oil companies – ExxonMobil, Shell, BP, ConocoPhillips – have active programs in this area. It is a naïve view to think that the oil industry as a whole will fail to anticipate the changing markets. That’s why I always think it is humorous that people feel the ethanol industry is a threat. If the oil industry thought it was a threat, there is nothing keeping them from getting involved.

Paul Sankey of Deutsche Bank just put forth both views in a new report. As I have mentioned previously, I think Sankey is an analyst who really understands the industry. And I agree with his first comments. I just don’t think he is right about the second point.

Don’t Fill Up on ConocoPhillips

That one is a somewhat misleading title because he is recommending ConocoPhillips (which I do own):

DESPITE NUMEROUS SIGNS that the global economy is still struggling, just about everyone following energy predicts at least one more spike in oil prices in coming years.

It’s just that scenario that prompted Deutsche Bank analyst Paul Sankey to publish today a 61-page opus to clients in which he upgraded shares of ConocoPhillips (COP) to “Buy” from “Hold” and raised his price target to $55 from $40.

Sankey’s thesis — and he’s not alone — is that Conoco will benefit in such a scenario by being able to sit back and milk profits from its existing reserves of oil with minimal new investment, thus leading to generous cash flows.

In brief, Sankey sees global demand surging again with economic rejuvenation, leading to a spike in oil of $175 per barrel in 2016, after which developments in global fuel efficiency, specifically electric cars, will cause demand for crude to fall off precipitously, until oil comes back into equilibrium with supply at $100 per barrel in 2030.

Sankey spells out why he is long-term bearish on the oil companies:

Peak Oil: The End Of the Oil Age is Near, Deutsche Bank Says

Deutsche Bank expects the electric car to become a truly “disruptive technology” which takes off around the world, sending demand for gasoline into an “inexorable and accelerating decline.”

In 2020, the bank expects electric and hybrid vehicles to account for 25% of new car sales—in both the U.S. and China. “We expect [electric propulsion] will reverse the dynamics of world oil demand, and spell the end of the oil age,” the bank writes.

But won’t cheaper oil in the future just lead to a revival in oil demand? That’s what’s happened in every other cycle. Au contraire, says the bank: Just as the explosion of digital cameras made the cost of film irrelevant, the growth of electric cars will make the price of oil (and gasoline) all but irrelevant for transportation.

He could be right, but I am betting against it. But I may find that in 20 years ConocoPhillips’ core business is something entirely different than it is today.

ExxonMobil’s MTG Technology

One of the more interesting presentations for me at the gasification conference has been ExxonMobil’s work on a different kind of coal-to-liquids (CTL) technology. Conventional CTL would involve gasification of the coal to syngas, followed by a Fischer Tropsch reaction that converts the gas into liquid fuels such as diesel. Exxon has a different process, in which they gasify the coal, but then they turn it into methanol. As I have said before, methanol can be made quite efficiently, and I think it’s a shame that it wasn’t allowed to compete with ethanol on an equal footing. But the technology doesn’t stop at methanol. The methanol is dehydrated to di-methyl-ether (DME, also a nice fuel). The DME is then passed over a catalyst and converted to gasoline in yields of around 90%. The technology is called methanol-to-gasoline (MTG).

The process has been around for a while, but hasn’t gotten much attention. In the 80’s and 90’s, they ran a 14,500 bbl/day plant in New Zealand. As far as synthetic fuel facilities go, that’s a big plant with an impressive track record of operation. The on-stream reliability of the plant was over 95% during its operation. (Following the oil price collapse in the 90’s, the plant stopped upgrading the methanol, and just made methanol the end product).

The advantage of the process is that capital costs are reportedly lower than FT, and the product is gasoline – in high demand in the U.S. The disadvantage is that the process produces relatively little diesel and jet fuel. The military and various airlines are highly interested in FT because of its ability to supply these important fuels.

Exxon reports that a new plant, based on 2nd generation technology with better heat integration and process efficiency, has been built in Shanxi, China. At 2,500 bbl/day, the facility is smaller than the earlier New Zealand facility, but Exxon has licensed MTG technology to a pair of companies in the U.S. DKRW announced in 2007 that they would utilize MTG in a 15,000 bbl/day facility in Medicine Bow, WY. Synthesis Energy Systems announced in September 2008 that they would license MTG for their global CTL projects.

While Exxon seems to be more focused on coal to gasoline, there is no reason this process couldn’t be used to turn natural gas or biomass into gasoline (GTL and BTL). This technology could be complementary to FT technology, providing gasoline while FT supplies the liquid fuels needed for airlines, marine applications, long-haul trucking, and the military.

During the Q&A, though, one guy asked “If this is so great, why aren’t you building these plants yourselves?” The answer was that they weren’t experts, and only wanted to license.

October 6, 2009 Posted by | btl, cellulosic ethanol, ConocoPhillips, COP, ExxonMobil, Paul Sankey, range fuels, XOM | 115 Comments

My Point Exactly

I missed this story when it came out last week:

Hydrocarbon biofuels’ promise tops that of ethanol, gasoline

John Regalbuto, a chemical engineer at the University of Illinois, Chicago, and director of the NSF catalysis and biocatalysis program, wrote in Science that biomass-derived fuels are not far from being part of the energy mix as a replacement for gasoline, diesel and jet fuel.

Hydrocarbon fuels can be directly produced from the sugars of woody biomass — forest waste, cornstalks or switchgrass — through microbial fermentation or liquid-phase catalysis, he wrote. They can be produced by pyrolysis or gasification directly from the woody biomass. And they can be produced by converting the lipids of nonfood crops and algae.

“The drawback to using ethanol as a complete replacement for gasoline … is not only the high cost of its production from cellulose but also its lower energy density,” Regalbuto wrote. “Ethanol has two-thirds the energy density of gasoline, and cars running on E85 (85 percent ethanol and 15 percent gasoline) get about 30 percent lower gas mileage.”

I am not so concerned about the energy density as I am the prospects for ever being able to produce ethanol from cellulose at a reasonable energy efficiency. By that, I mean this: If I start with biomass with the energy content of a million BTUs, how much ends up as usable energy?

And the money quote, which has been my argument all along:

“I’m not a lobbyist but a scientist, but if I were, I would argue for a subsidy for all biofuels and not just ethanol,” he said in an e-mail. “It’s too early to tell which route — pyrolysis, aqueous phase processing, gasification or synthetic biology — will win out; we may well have versions of all four contributing to the mix. I would simply say that lignocellulosic hydrocarbons appear to give far more promise than cellulosic ethanol.”

Without any subsidies at all, fossil fuels would kill pretty much all biofuels except for sugarcane ethanol from the tropics. If you subsidize all biofuels equally, corn ethanol can compete as a 1st generation fuel, but gasification or pyrolysis will win out over cellulosic ethanol. The energy efficiency of cellulosic ethanol relative to gasification is far too low for it to compete in the long run. I am not naive enough to think that corn ethanol is going away – it has too much support in Congress. But the 2nd generation will only see cellulosic in niche applications. Gasification is where I am placing my bet.

August 21, 2009 Posted by | biomass gasification, btl, cellulose, cellulosic ethanol | 37 Comments

Rentech Making Waves

The following story posed a bit of a dilemma for me. In my new role, there will be potential conflicts of interest in some of the stories I may post, and until I elaborate on what I am doing, I am trying to avoid posting anything that might fall into that category.

When I first saw this story earlier today – and in fact received the press release from Rentech (RTK) – my first thought was that this sort of fell into that category. Why? Two reasons. First, Rentech’s Senior Vice President and Chief Technology Officer Harold Wright is my former manager and a friend. Second, in my new role I have interests that are of the same nature as some of Rentech’s. That means that we could be allies or we could be competitors, but I can’t say I am a disinterested party. So I finally decided that I should simply declare this, and post the story, which is really a culmination of several Rentech developments.

Having said that, Rentech has really been generating a lot of buzz lately. They are currently operating the only fully-integrated synthetic transportation fuels production facility in the U.S., and in partnership with ClearFuels Technology Inc., they are building a “20 ton-per-day biomass gasifier designed to produce syngas from bagasse, virgin wood waste and other cellulosic feedstocks at Rentech’s Product Demonstration Unit (PDU) in Colorado. The gasifier will be integrated with Rentech’s Fischer-Tropsch Process and UOP’s upgrading technology to produce renewable drop-in synthetic jet and diesel fuel at demonstration scale.”

Rentech also recently announced their Rialto Project, designed to “produce approximately 600 barrels per day of pure renewable synthetic fuels and export approximately 35 megawatts of renewable electric power.” They will use Rentech-SilvaGas biomass gasification technology, and green waste as the feedstock.

Today’s press release announced an off-take agreement with several airlines. You can read the press release below. Rentech stock was up 86% today on the news. They also announced a profit last week of $0.22 a share (triple analysts’ expectations), and were up 56% on that news.

I have strongly voiced my views that I believe the future belongs to gasification. Keep an eye on Rentech’s developments in this area.

——————————–

Rentech to Supply Renewable Synthetic Fuels to Eight Airlines for Ground Service Equipment Operations at Los Angeles International Airport

Initial Purchasers Include Alaska Airlines, American Airlines, Continental Airlines, Delta Air Lines, Southwest Airlines, United Airlines, UPS Airlines and US Airways, with Potential for Additional Purchasers

LOS ANGELES (August 18, 2009) – Rentech, Inc. (NYSE AMEX: RTK) announced today that it has signed an unprecedented multi-year agreement to supply eight airlines with up to 1.5 million gallons per year of renewable synthetic diesel (RenDiesel®) for ground service equipment operations at Los Angeles International Airport (LAX) beginning in late 2012, when the plant that will produce the fuel is scheduled to go into service.

The initial purchasers under the agreement with Aircraft Service International Group (ASIG), the entity that provides fueling services to many airlines that operate at LAX, are Alaska Airlines, American Airlines, Continental Airlines, Delta Air Lines, Southwest Airlines, United Airlines, UPS Airlines and US Airways. Additional airline purchasers of RenDiesel® can be added under the agreement with ASIG.

The agreement is the first of its kind to supply renewable synthetic fuels to multiple domestic airlines. The renewable RenDiesel® fuel to be supplied to the airlines would be produced from green waste at Rentech’s proposed Rialto Renewable Energy Center (Rialto Project). The renewable diesel fuel will have a carbon footprint of near zero. RenDiesel® exceeds all applicable fuels standards, is biodegradable and is virtually free of particulates, sulfur and aromatics. RenDiesel® is compatible with existing engines and pipelines, providing an immediate solution to the transportation sector’s requirements to meet targets established by California’s Low Carbon Fuel Standard.

D. Hunt Ramsbottom, President and Chief Executive Officer of Rentech said, “This commercial purchase contract among Rentech, ASIG and the airlines validates the growing demand for synthetic fuels produced by the Rentech Process. The low-emissions profile and near-zero carbon footprint of our renewable RenDiesel will guarantee that the LAX ground service vehicles using this fuel will be among the cleanest and greenest of their kind.” Mr. Ramsbottom continued, “We expect this agreement to serve as a model for future supply relationships at other airports and for other fuels, including Rentech’s synthetic jet fuel, which was recently approved for commercial airline use.”

Glenn F. Tilton, Air Transport Association of America (ATA) Board Chairman and UAL Corporation Chairman, President and Chief Executive Officer, said, “We are proud to take part in this innovative, collective endeavor that, over time, will further reduce greenhouse gas emissions and improve local air quality through the use of greener fuels.” Mr. Tilton continued, “This transaction promises to be the first of many such green fuel purchase agreements by the commercial aviation industry. It exemplifies the ongoing commitment of airlines and energy suppliers to diversify our fuel sources while contributing to a cleaner environment and adding new jobs to the economy.”

ASIG is thrilled to have been instrumental in reaching this landmark deal with the airlines and Rentech, reinforcing our strong commitment to our airline customers and environmental stewardship,” said ASIG President Keith P. Ryan. “We are proud to be on the forefront of this innovative effort to advance aviation environmental progress.”

Gina Marie Lindsey, Executive Director of Los Angeles World Airports (LAWA), commented, “This collaborative effort is yet another environmentally friendly initiative that we and the airlines are pursuing at Los Angeles-area airports. It shows what we can accomplish by working together toward a common and necessary goal.”

Rentech is developing a commercial-scale facility in Rialto, California, to produce renewable electric power and the cleanest diesel in California, each with a carbon footprint near zero. The project is currently designed to produce approximately 600 barrels per day of renewable, ultra-clean synthetic fuels and 35 megawatts of renewable electricity (enough to power approximately. 30,000 homes), primarily from urban woody green waste, such as yard clippings. The facility is expected to come online in 2012.

August 19, 2009 Posted by | biomass gasification, btl, investing, Rentech | 57 Comments

The Long Recession

Sometimes people ask me what I think will happen as a result of peak oil. Well, it depends. We could see alternatives – natural gas, ethanol, GTL, CTL, etc. – fill the gap of falling oil supplies for a while. It just depends on how quickly production falls. But if the alternatives are not up to the task, then I think what we will see – borrowing terminology from The Long Emergency– is The Long Recession. Here’s how it would work.

As economies heat up, demand for oil increases. This puts upward pressure on oil prices, which can ultimately cause a recession such as the one we are in now. Historically, spiking oil prices tend to consume disposable income and lead to recessions. Jeff Rubin, whose new book I recently reviewed, has claimed that four of the past five recessions were caused by spiking oil prices.

In normal cycles, oil companies build up capacity when oil prices are high. A recession caused by high oil prices, combined with overcapacity built up during the price rise, can keep oil prices at bay for a long time. But what if oil capacity can’t be overbuilt, because oil production has peaked? In this situation, oil prices will start to recover just as soon as the economy starts to come out of recession. This may in turn “restall” the economy, leading to a long recession that just repeats the cycle every time the economy begins to recover.

It is hard to say that we are at that point. However, oil prices have recovered quite a bit of lost ground, and have now crossed $70/bbl:

$70 oil menaces budding recovery

At the end of May CNNMoney.com ran a story asking if $60 oil will kill any economic recovery. ‘No,” most analysts said – consumers could shoulder $60 crude, and analysts didn’t see prices going much higher.

Now oil is touching $70 a barrel. Goldman Sachs recently said it sees crude at $85 by the year’s end. With the economy still on life support, oil is drifting dangerously close to being the wet blanket at the recovery’s party.

Hmm. Sounds like what could be waiting on the other side of this recession is…a recession.

There are alternatives that start to become economical with oil at $70 or more. Oil sands, for one. Natural gas vehicles also start to look pretty good at those oil prices. Even GTL, CTL, and BTL stand a chance of being economical if oil prices hang around at lofty levels. But companies – especially oil companies – are pretty risk averse when it comes to predicting oil prices. I doubt any U.S. oil companies are basing future economics on the expectation of > $70 oil. If they were, you would see far greater investments into unconventional energy sources.

June 9, 2009 Posted by | btl, CTL, economics, gtl, oil prices, recession | 20 Comments

Rentech Announces BTL Plant

Still on vacation, but an interesting announcement yesterday by Rentech:

Rialto Project

Our proposed Rialto Renewable Energy Center (Rialto Project) will be located in Rialto, California. The facility is designed to produce approximately 600 barrels per day of pure renewable synthetic fuels and export approximately 35 megawatts of renewable electric power. The renewable power is expected to qualify under California’s Renewable Portfolio Standard (RPS) program, which requires utilities to increase the amount of electric power they sell from qualified renewable-energy resources. The plant will be capable of providing enough electricity for approximately 30,000 homes.

Rentech has entered into a licensing agreement with SilvaGas Corporation for the biomass gasification technology for the Rialto facility. Rentech’s proprietary technology for the conditioning and clean-up of syngas will provide the next critical link in the technology chain after gasification. The conditioned syngas will be converted by the Rentech Process in a commercial scale reactor to finished, ultra-clean products such as synthetic diesel and naphtha using upgrading technologies under an alliance between Rentech and UOP, a Honeywell Company. Renewable electric power will be produced at the facility by using conventional high-efficiency gas turbine technology. The power is anticipated to be sold to local utilities under the California RPS program.

The primary feedstock for the Rialto Project will be urban woody green waste such as yard clippings, for which Rentech is currently negotiating supply agreements. The location of the project will provide local green waste haulers with a cost-effective alternative to increasingly scarce landfills for the disposal of woody green waste. The plant is designed to also use biosolids for a portion of the feedstock which is expected to be provided under a supply agreement with EnerTech Environmental.

Readers may know that I am quite interested in gasification as a long-term sustainable option for delivering liquid fuels and/or electricity. (See previous essays on Choren, who have built the world’s first scaled-up BTL plant).

Incidentally, their CTO used to be my direct supervisor at ConocoPhillips in 2002-2003:

Dr. Harold A. Wright – Senior Vice President and Chief Technology Officer

Dr. Harold Wright leverages deep experience in fuel technology development to serve as Senior Vice President and Chief Technology Officer of Rentech. He joined the Company in 2005 after serving as Vice President of Technology for Eltron Research & Development, headquartered in Boulder, Colorado. This followed a 14-year tenure with ConocoPhillips where he worked in various capacities including Director of gas-to-liquids (GTL) research and development from 2004-05 and Director of synthesis gas development from 2000-04. In these roles, he was responsible for synthesis gas technology development; GTL commercial reactor design; directing GTL catalyst development; and product upgrading technology development. He oversaw all aspects of the company’s scale-up of GTL technology, which resulted in a 400 barrel per day demonstration plant in Ponca City, Oklahoma. With 24 U.S. Patents issued to his credit, he is also a registered patent agent and is authorized to practice patent law before the U.S. Patent and Trademark Office. Dr. Wright received a B.S. in chemical engineering, cum laude, from the University of Missouri-Columbia and a Ph.D. in chemical engineering from Purdue University.

Returning to Texas from Hawaii this evening, with things returning to normal over the next few days.

May 12, 2009 Posted by | biomass gasification, btl, Choren, Rentech | 40 Comments

Renewable Diesel Primer

Given the recent news that biodiesel has caused buses in Minnesota to malfunction in cold weather, I thought this would be a good time to review the differences between diesel, biodiesel, and green diesel. In order to explain the key issues, I am going to excerpt from the chapter on renewable diesel that I wrote for Biofuels, Solar and Wind as Renewable Energy Systems: Benefits and Risks.

First, what happened in Minnesota?



Biodiesel fuel woes close Bloomington schools

All schools in the Bloomington School District will be closed today after state-required biodiesel fuel clogged in school buses Thursday morning and left dozens of students stranded in frigid weather, the district said late Thursday.

Rick Kaufman, the district’s spokesman, said elements in the biodiesel fuel that turn into a gel-like substance at temperatures below 10 degrees clogged about a dozen district buses Thursday morning. Some buses weren’t able to operate at all and others experienced problems while picking up students, he said.

And in case you think this was an isolated incident:

The decision to close school today came after district officials consulted with several neighboring districts that were experiencing similar problems. Bloomington staffers tried to get a waiver to bypass the state requirement and use pure diesel fuel, but they weren’t able to do so in enough time, Kaufman said. They also decided against scheduling a two-hour delay because the temperatures weren’t expected to rise enough that the problem would be eliminated.

What is Biodiesel?

Biodiesel is defined as the mono-alkyl ester product derived from lipid1 feedstock like SVO or animal fats (Knothe 2001). The chemical structure is distinctly different from petroleum diesel, and biodiesel has somewhat different physical and chemical properties from petroleum diesel.

Biodiesel is normally produced by reacting triglycerides (long-chain fatty acids contained in the lipids) with an alcohol in a base-catalyzed reaction (Sheehan 1998) as shown in Figure 1. Methanol, ethanol, or even longer chain alcohols may be used as the alcohol, although lower-cost and faster-reacting methanol2 is typically preferred. The primary products of the reaction are the alkyl ester (e.g., methyl ester if methanol is used) and glycerol. The key advantage over straight vegetable oil (SVO) is that the viscosity is greatly reduced, albeit at the cost of additional processing and a glycerol byproduct.

The key thing to note here is that biodiesel contains oxygen atoms (the ‘O’ in the biodiesel structure above), but petroleum diesel and green diesel do not. This leads to different physical properties for biodiesel.

Biodiesel Characteristics

Biodiesel is reportedly nontoxic and biodegradable (Sheehan et al. 1998). An EPA study published in 2002 showed that the impact of biodiesel on exhaust emissions was mostly favorable (EPA 2002). Compared to petroleum diesel, a pure blend of biodiesel was estimated to increase the emission of NOx by 10%, but reduce emissions of carbon monoxide and particulate matter by almost 50%. Hydrocarbon emissions from biodiesel were reduced by almost 70% relative to petroleum diesel. However, other researchers have reached different conclusions. While confirming the NOx reduction observed in the EPA studies, Altin et al. determined that both biodiesel and SVO increase CO emissions over petroleum diesel (Altin et al. 2001). They also determined that the energy content of biodiesel and SVO was about 10% lower than for petroleum diesel. This means that a larger volume of biodiesel consumption is required per distance traveled, increasing the total emissions over what a comparison of the exhaust concentrations would imply.

The natural cetane3 number for biodiesel in the 2002 EPA study was found to be higher than for petroleum diesel (55 vs. 44). Altin et al. again reported a different result, finding that in most cases the natural cetane numbers were lower for biodiesel than for petroleum diesel. These discrepancies in cetane results have been attributed to the differences in the quality of the oil feedstock, and to whether the biodiesel had been distilled (Van Gerpen 1996).

A major attraction of biodiesel is that it is easy to produce. An individual with a minimal amount of equipment or expertise can learn to produce biodiesel. With the exception of SVO, production of renewable diesel by hobbyists is limited to biodiesel because a much larger capital expenditure is required for other renewable diesel technologies.

Biodiesel does have characteristics that make it problematic in cold weather conditions. The cloud and pour points4 of biodiesel can be 20° C or higher than for petroleum diesel (Kinast 2003). This is a severe disadvantage for the usage of biodiesel in cold climates, and limits the blending percentage with petroleum diesel in cold weather.

Green Diesel

Definition

Another form of renewable diesel is ‘green diesel.’ Green diesel is chemically the same as petroleum diesel, but it is made from recently living biomass. Unlike biodiesel, which is an ester and has different chemical properties from petroleum diesel, green diesel is composed of long-chain hydrocarbons, and can be mixed with petroleum diesel in any proportion for use as transportation fuel. Green diesel technology is frequently referred to as second-generation renewable diesel technology.

There are two methods of making green diesel. One is to hydroprocess vegetable oil or animal fats. Hydroprocessing may occur in the same facilities used to process petroleum. The second method of making green diesel involves partially combusting a biomass source to produce carbon monoxide and hydrogen – syngas – and then utilizing the Fischer-Tropsch reaction to produce complex hydrocarbons. This process is commonly called the biomass-to-liquids, or BTL process.

Hydroprocessing

Hydroprocessing is the process of reacting a feed stock with hydrogen under elevated temperature and pressure in order to change the chemical properties of the feed stock. The technology has long been used in the petroleum industry to ‘crack’, or convert very large organic molecules into smaller organic molecules, ranging from those suitable for liquid petroleum gas (LPG) applications through those suitable for use as distillate fuels.

In recent years, hydroprocessing technology has been used to convert lipid feed stocks into distillate fuels. The resulting products are a distillate fuel with properties very similar to petroleum diesel, and propane (Hodge 2006). The primary advantages over first-generation biodiesel technology are: 1). The cold weather properties are superior; 2). The propane byproduct is preferable over glycerol byproduct; 3). The heating content is greater; 4). The cetane number is greater; and 5). Capital costs and operating costs are lower (Arena et al. 2006).

A number of companies have announced renewable diesel projects based on hydroprocessing technology. In May 2007 Neste Oil Corporation in Finland inaugurated a plant that will produce 170,000 t/a of renewable diesel fuel from a mix of vegetable oil and animal fat (Neste 2007). Italy’s Eni has announced plans for a facility in Leghorn, Italy that will hydrotreat vegetable oil for supplying European markets. Brazil’s Petrobras is currently producing renewable diesel via their patented hydrocracking technology (NREL 2006). And in April 2007 ConocoPhillips, after testing their hydrocracking technology to make renewable diesel from rapeseed oil in Whitegate, Ireland, announced a partnership with Tyson Foods to convert waste animal fat into diesel (ConocoPhillips 2007).

Like biodiesel production, which normally utilizes fossil fuel-derived methanol, hydroprocessing requires fossil fuel-derived hydrogen5. No definitive life cycle analyses have been performed for diesel produced via hydroprocessing. Therefore, the energy return and overall environmental impact have yet to be quantified.

Biomass-to-Liquids

When an organic material is burned (e.g., natural gas, coal, biomass), it can be completely oxidized (gasified) to carbon dioxide and water, or it can be partially oxidized to carbon monoxide and hydrogen. The latter partial oxidation (POX), or gasification reaction, is accomplished by restricting the amount of oxygen during the combustion. The resulting mixture of carbon monoxide and hydrogen is called synthesis gas (syngas) and can be used as the starting material for a wide variety of organic compounds, including transportation fuels.

Syngas may be used to produce long-chain hydrocarbons via the Fischer-Tropsch (FT) reaction. The FT reaction, invented by German chemists Franz Fischer and Hans Tropsch in the 1920s, was used by Germany during World War II to produce synthetic fuels for their war effort. The FT reaction has received a great deal of interest lately because of the potential for converting natural gas, coal, or biomass into liquid transportation fuels. These processes are respectively referred to as gas-to-liquids (GTL), coal-to-liquids (CTL), and biomass-to-liquids (BTL), and the resulting fuels are ‘synthetic fuels’ or ‘XTL fuels’. Of the XTL processes, BTL produces the only renewable fuel, as it utilizes recently anthropogenic (atmospheric) carbon.

Renewable diesel produced via BTL technology has one substantial advantage over biodiesel and hydrocracking technologies: Any source of biomass may be converted via BTL. Biodiesel and hydrocracking processes are limited to lipids. This restricts their application to a feedstock that is very small in the context of the world’s available biomass. BTL is the only renewable diesel technology with the potential for converting a wide range of waste biomass.

Like GTL and CTL, development of BTL is presently hampered by high capital costs. According to the Energy Information Administration’s Annual Energy Outlook 2006, capital costs per daily barrel of production are $15,000-20,000 for a petroleum refinery, $20,000-$30,000 for an ethanol plant, $30,000 for GTL, $60,000 for CTL, and $120,000-$140,000 for BTL (EIA 2006).

While a great deal of research, development, and commercial experience has gone into FT technology in recent years6, biomass gasification biomass gasification technology is a relatively young field, which may partially explain the high capital costs. Nevertheless, the technology is progressing. Germany’s Choren is building a plant in Freiberg, Germany to produce 15,000 tons/yr of their SunDiesel® product starting in 2008 (Ledford 2006).

Straight Vegetable Oil

Unmodified vegetable-derived triglycerides, commonly known as vegetable oil, may also be used to fuel a diesel engine. Rudolf Diesel demonstrated the use of peanut oil as fuel for one of his diesel engines at the Paris Exposition in 1900 (Altin et al. 2001). Modern diesel engines are also capable of running on straight (unmodified) vegetable oil (SVO) or waste grease, with some loss of power over petroleum diesel (West 2004). Numerous engine performance and emission tests have been conducted with SVO derived from many different sources, either as a standalone fuel or as a mixture with petroleum diesel (Fort and Blumberg 1982, Schlick et al. 1988, Hemmerlein et al. 1991, Goering et al. 1982).

The advantage of SVO as fuel is that a minimal amount of processing is required, which lowers the production costs of the fuel. The energy return for SVO, defined as energy output over the energy required to produce the fuel, will also be higher due to the avoidance of energy intensive downstream processing steps.

There are several disadvantages of using SVO as fuel. The first is that researchers have found that engine performance suffers, and that hydrocarbon and carbon monoxide emissions increase relative to petroleum diesel. Particulate emissions were also observed to be higher with SVO. However, the same studies found that nitrogen oxide (NOx) emissions were lower for SVO (Altin et al. 2001). On long-term tests, carbon deposits have been found in the combustion chamber, and sticky gum deposits have occurred in the fuel lines (Fort and Blumberg 1982). SVO also has a very high viscosity relative to most diesel fuels. This reduces its ability to flow, especially in cold weather. This characteristic may be compensated for by heating up the SVO, or by blending it with larger volumes of lower viscosity diesel fuels.

Conclusions

In order to understand the potential problems with biodiesel under cold weather conditions, it is important to understand that biodiesel is chemically different from petroleum or green diesel – and thus should not be expected to have the same chemical properties. Biodiesel is an ester, while petroleum and green diesel are hydrocarbons. The only reason it is called ‘diesel’ is that it can fuel a diesel engine. Likewise vegetable oil, butanol, and even ethanol blends could be called ‘diesels’, as each of these can be used to fuel a diesel engine.

Finally, it should also be noted that petroleum diesel is not immune from cold weather gelling. It is just that these problems don’t begin to occur until the temperatures are much lower than those at which biodiesel begins to gel. If extremely cold weather conditions are likely, then petroleum diesel is blended differently. More kerosene is put into the mixture, which is a lighter diesel (and has a shorter carbon chain length and is just a little heavier than gasoline) and is referred to as #1 diesel.

Footnotes

1. Lipids are oils obtained from recently living biomass. Examples are soybean oil, rapeseed oil, palm oil, and animal fats. Petroleum is obtained from ancient biomass and will be specifically referred to as ‘crude oil’ or the corresponding product ‘petroleum diesel.’

2. Methanol is usually produced from natural gas, although some is commercially produced from light petroleum products or from coal. Methanol therefore represents a significant – but often overlooked – fossil fuel input into the biodiesel process.

3. The cetane number is a measure of the ignition quality of diesel fuel based on ignition delay in a compression ignition engine. The ignition delay is the time between the start of the injection and the ignition. Higher cetane numbers mean shorter ignition delays and better ignition quality.

4. The cloud point is the temperature at which the fuel becomes cloudy due to the precipitation of wax. The pour point is the lowest temperature at which the fuel will still freely flow.

5. Hydrogen is produced almost exclusively from natural gas.

6. Companies actively involved in developing Fischer-Tropsch technology include Shell, operating a GTL facility in Bintulu, Malaysia since 1993; Sasol, with CTL and GTL experience in South Africa; and ConocoPhillips and Syntroleum, both with GTL demonstration plants in Oklahoma.

References

Altin, R., Cetinkaya S., & Yucesu, H.S. (2001). The potential of using vegetable oil fuels as fuel for Diesel engines. Energy Convers. Manage. 42, 529–538.

Arena, B.; Holmgren, J.; Marinangeli, R.; Marker, T.; McCall, M.; Petri, J.; Czernik, S.; Elliot, D.; & Shonnard, D. (2006, September). Opportunities for Biorenewables in Petroleum Refineries (Paper presented at the Rio Oil & Gas Expo and Conference, Instituto Braserileiro de Petroleo e Gas).

ConocoPhillips. (2007). ConocoPhillips and Tyson Foods Announce Strategic Alliance To Produce Next Generation Renewable Diesel Fuel. Retrieved July 21, 2007 from the ConocoPhillips corporate web site: http://www.conocophillips.com/newsroom/news_releases/2007+News+Releases/041607.htm

EIA, Energy Information Administration. (2006). Annual Energy Outlook 2006. DOE/EIA-0383, 57-58.

EPA, U.S. Environmental Protection Agency. (2002). A Comprehensive Analysis of Biodiesel Impacts on Exhaust Emissions. EPA420-P-02-001.

Fort, E. F. & Blumberg, P. N. (1982). Performance and durability of a turbocharged diesel fueled with cottonseed oil blends. (Paper presented at the International Conference on Plant and Vegetable Oils as Fuel, ASAE).

Goering C.E., Schwab, A. Dougherty, M. Pryde, M. & Heakin, A. (1981). Fuel properties of eleven vegetable oils. (Paper presented at the American Society of Agricultural Engineers meeting, Chicago, IL, USA).

Hodge, C. (2006). Chemistry and Emissions of NExBTL. (Presented at the University of California, Davis). Retrieved July 21, 2007 from http://bioenergy.ucdavis.edu/materials/NExBTL%20Enviro%20Benefits%20of%20paraffins.pdf

Hemmerlein M., Korte V., & Richter HS. (1991). Performance, exhaust emission and durability of modern diesel engines running on rapeseed oil. SAE Paper 910848.

Kinast, J. NREL, National Renewable Energy Laboratory. (2003). Production of Biodiesels from Multiple Feed-stocks and Properties of Biodiesels and Biodiesel/Diesel Blends. NREL/SR-510-31460.

Knothe, G. (2001). Historical perspectives on vegetable oil-based diesel fuels. INFORM 12 (11), 1103–7.

Ledford, H. (2006). Liquid fuel synthesis: Making it up as you go along. Nature 444, 677 – 678.

Neste Oil Corporation. (2007). Neste Oil inaugurates new diesel line and biodiesel plant at Porvoo. Retrieved July 21, 2007 from http://www.nesteoil.com/default.asp?path=1,41,540,1259,1260,7439,8400

NREL, National Renewable Energy Laboratory. (2006). Biodiesel and Other Renewable Diesel Fuels, NREL/FS-510-40419 Sheehan, J. NREL, National Renewable Energy Laboratory. (1998). An Overview of Biodiesel and Petroleum Diesel Life Cycles, NREL/TP-580-24772.

Schlick M. L., Hanna, M. A., & Schinstock, J. L. (1988). Soybean and sunflower oil performance in diesel engine. ASAE 31 (5).

Van Gerpen, J. (1996). Cetane Number Testing of Biodiesel. (Paper presented at the Third Liquid Fuel Conference: Liquid Fuel and Industrial Products from Renewable Resources, St. Joseph, MI).

West, T. (2004). The Vegetable-Oil Alternative. [Electronic version]. Car and Driver. Retrieved June 28, 2007 from http://www.caranddriver.com/article.asp?section_id=4&article_id=7818

Book Chapter Outline

While I have posted extended excerpts from my book chapter, I covered quite a bit more material in there. Here is the full chapter outline:

Renewable Diesel by Robert Rapier

1. The Diesel Engine

2. Ecological Limits

3. Straight Vegetable Oil (SVO)

4. Biodiesel

4.1.1. Definition/Production Process

4.1.2. Fuel Characteristics

4.1.3. Energy Return

4.1.4. Glycerin Byproduct

5. Green Diesel

5.1.1. Definition/Production

5.1.1.1. Hydroprocessing

5.1.1.2. BTL – Gasification/Fischer-Tropsch

6. Feedstocks

6.1.1. Soybean Oil

6.1.2. Palm Oil

6.1.3. Rapeseed Oil

6.1.4. Jatropha

6.1.5. Algae

6.1.6. Animal Fats

6.1.7. Waste Biomass

7. Conclusions

8. Conversion Factors and Calculations

8.1. Conversion Factors

8.2. Calculations

9. References

January 17, 2009 Posted by | biodiesel, biomass gasification, btl, Choren, ConocoPhillips, green diesel, Neste, renewable diesel | 34 Comments

Renewable Diesel Primer

Given the recent news that biodiesel has caused buses in Minnesota to malfunction in cold weather, I thought this would be a good time to review the differences between diesel, biodiesel, and green diesel. In order to explain the key issues, I am going to excerpt from the chapter on renewable diesel that I wrote for Biofuels, Solar and Wind as Renewable Energy Systems: Benefits and Risks.

First, what happened in Minnesota?



Biodiesel fuel woes close Bloomington schools

All schools in the Bloomington School District will be closed today after state-required biodiesel fuel clogged in school buses Thursday morning and left dozens of students stranded in frigid weather, the district said late Thursday.

Rick Kaufman, the district’s spokesman, said elements in the biodiesel fuel that turn into a gel-like substance at temperatures below 10 degrees clogged about a dozen district buses Thursday morning. Some buses weren’t able to operate at all and others experienced problems while picking up students, he said.

And in case you think this was an isolated incident:

The decision to close school today came after district officials consulted with several neighboring districts that were experiencing similar problems. Bloomington staffers tried to get a waiver to bypass the state requirement and use pure diesel fuel, but they weren’t able to do so in enough time, Kaufman said. They also decided against scheduling a two-hour delay because the temperatures weren’t expected to rise enough that the problem would be eliminated.

What is Biodiesel?

Biodiesel is defined as the mono-alkyl ester product derived from lipid1 feedstock like SVO or animal fats (Knothe 2001). The chemical structure is distinctly different from petroleum diesel, and biodiesel has somewhat different physical and chemical properties from petroleum diesel.

Biodiesel is normally produced by reacting triglycerides (long-chain fatty acids contained in the lipids) with an alcohol in a base-catalyzed reaction (Sheehan 1998) as shown in Figure 1. Methanol, ethanol, or even longer chain alcohols may be used as the alcohol, although lower-cost and faster-reacting methanol2 is typically preferred. The primary products of the reaction are the alkyl ester (e.g., methyl ester if methanol is used) and glycerol. The key advantage over straight vegetable oil (SVO) is that the viscosity is greatly reduced, albeit at the cost of additional processing and a glycerol byproduct.

The key thing to note here is that biodiesel contains oxygen atoms (the ‘O’ in the biodiesel structure above), but petroleum diesel and green diesel do not. This leads to different physical properties for biodiesel.

Biodiesel Characteristics

Biodiesel is reportedly nontoxic and biodegradable (Sheehan et al. 1998). An EPA study published in 2002 showed that the impact of biodiesel on exhaust emissions was mostly favorable (EPA 2002). Compared to petroleum diesel, a pure blend of biodiesel was estimated to increase the emission of NOx by 10%, but reduce emissions of carbon monoxide and particulate matter by almost 50%. Hydrocarbon emissions from biodiesel were reduced by almost 70% relative to petroleum diesel. However, other researchers have reached different conclusions. While confirming the NOx reduction observed in the EPA studies, Altin et al. determined that both biodiesel and SVO increase CO emissions over petroleum diesel (Altin et al. 2001). They also determined that the energy content of biodiesel and SVO was about 10% lower than for petroleum diesel. This means that a larger volume of biodiesel consumption is required per distance traveled, increasing the total emissions over what a comparison of the exhaust concentrations would imply.

The natural cetane3 number for biodiesel in the 2002 EPA study was found to be higher than for petroleum diesel (55 vs. 44). Altin et al. again reported a different result, finding that in most cases the natural cetane numbers were lower for biodiesel than for petroleum diesel. These discrepancies in cetane results have been attributed to the differences in the quality of the oil feedstock, and to whether the biodiesel had been distilled (Van Gerpen 1996).

A major attraction of biodiesel is that it is easy to produce. An individual with a minimal amount of equipment or expertise can learn to produce biodiesel. With the exception of SVO, production of renewable diesel by hobbyists is limited to biodiesel because a much larger capital expenditure is required for other renewable diesel technologies.

Biodiesel does have characteristics that make it problematic in cold weather conditions. The cloud and pour points4 of biodiesel can be 20° C or higher than for petroleum diesel (Kinast 2003). This is a severe disadvantage for the usage of biodiesel in cold climates, and limits the blending percentage with petroleum diesel in cold weather.

Green Diesel

Definition

Another form of renewable diesel is ‘green diesel.’ Green diesel is chemically the same as petroleum diesel, but it is made from recently living biomass. Unlike biodiesel, which is an ester and has different chemical properties from petroleum diesel, green diesel is composed of long-chain hydrocarbons, and can be mixed with petroleum diesel in any proportion for use as transportation fuel. Green diesel technology is frequently referred to as second-generation renewable diesel technology.

There are two methods of making green diesel. One is to hydroprocess vegetable oil or animal fats. Hydroprocessing may occur in the same facilities used to process petroleum. The second method of making green diesel involves partially combusting a biomass source to produce carbon monoxide and hydrogen – syngas – and then utilizing the Fischer-Tropsch reaction to produce complex hydrocarbons. This process is commonly called the biomass-to-liquids, or BTL process.

Hydroprocessing

Hydroprocessing is the process of reacting a feed stock with hydrogen under elevated temperature and pressure in order to change the chemical properties of the feed stock. The technology has long been used in the petroleum industry to ‘crack’, or convert very large organic molecules into smaller organic molecules, ranging from those suitable for liquid petroleum gas (LPG) applications through those suitable for use as distillate fuels.

In recent years, hydroprocessing technology has been used to convert lipid feed stocks into distillate fuels. The resulting products are a distillate fuel with properties very similar to petroleum diesel, and propane (Hodge 2006). The primary advantages over first-generation biodiesel technology are: 1). The cold weather properties are superior; 2). The propane byproduct is preferable over glycerol byproduct; 3). The heating content is greater; 4). The cetane number is greater; and 5). Capital costs and operating costs are lower (Arena et al. 2006).

A number of companies have announced renewable diesel projects based on hydroprocessing technology. In May 2007 Neste Oil Corporation in Finland inaugurated a plant that will produce 170,000 t/a of renewable diesel fuel from a mix of vegetable oil and animal fat (Neste 2007). Italy’s Eni has announced plans for a facility in Leghorn, Italy that will hydrotreat vegetable oil for supplying European markets. Brazil’s Petrobras is currently producing renewable diesel via their patented hydrocracking technology (NREL 2006). And in April 2007 ConocoPhillips, after testing their hydrocracking technology to make renewable diesel from rapeseed oil in Whitegate, Ireland, announced a partnership with Tyson Foods to convert waste animal fat into diesel (ConocoPhillips 2007).

Like biodiesel production, which normally utilizes fossil fuel-derived methanol, hydroprocessing requires fossil fuel-derived hydrogen5. No definitive life cycle analyses have been performed for diesel produced via hydroprocessing. Therefore, the energy return and overall environmental impact have yet to be quantified.

Biomass-to-Liquids

When an organic material is burned (e.g., natural gas, coal, biomass), it can be completely oxidized (gasified) to carbon dioxide and water, or it can be partially oxidized to carbon monoxide and hydrogen. The latter partial oxidation (POX), or gasification reaction, is accomplished by restricting the amount of oxygen during the combustion. The resulting mixture of carbon monoxide and hydrogen is called synthesis gas (syngas) and can be used as the starting material for a wide variety of organic compounds, including transportation fuels.

Syngas may be used to produce long-chain hydrocarbons via the Fischer-Tropsch (FT) reaction. The FT reaction, invented by German chemists Franz Fischer and Hans Tropsch in the 1920s, was used by Germany during World War II to produce synthetic fuels for their war effort. The FT reaction has received a great deal of interest lately because of the potential for converting natural gas, coal, or biomass into liquid transportation fuels. These processes are respectively referred to as gas-to-liquids (GTL), coal-to-liquids (CTL), and biomass-to-liquids (BTL), and the resulting fuels are ‘synthetic fuels’ or ‘XTL fuels’. Of the XTL processes, BTL produces the only renewable fuel, as it utilizes recently anthropogenic (atmospheric) carbon.

Renewable diesel produced via BTL technology has one substantial advantage over biodiesel and hydrocracking technologies: Any source of biomass may be converted via BTL. Biodiesel and hydrocracking processes are limited to lipids. This restricts their application to a feedstock that is very small in the context of the world’s available biomass. BTL is the only renewable diesel technology with the potential for converting a wide range of waste biomass.

Like GTL and CTL, development of BTL is presently hampered by high capital costs. According to the Energy Information Administration’s Annual Energy Outlook 2006, capital costs per daily barrel of production are $15,000-20,000 for a petroleum refinery, $20,000-$30,000 for an ethanol plant, $30,000 for GTL, $60,000 for CTL, and $120,000-$140,000 for BTL (EIA 2006).

While a great deal of research, development, and commercial experience has gone into FT technology in recent years6, biomass gasification biomass gasification technology is a relatively young field, which may partially explain the high capital costs. Nevertheless, the technology is progressing. Germany’s Choren is building a plant in Freiberg, Germany to produce 15,000 tons/yr of their SunDiesel® product starting in 2008 (Ledford 2006).

Straight Vegetable Oil

Unmodified vegetable-derived triglycerides, commonly known as vegetable oil, may also be used to fuel a diesel engine. Rudolf Diesel demonstrated the use of peanut oil as fuel for one of his diesel engines at the Paris Exposition in 1900 (Altin et al. 2001). Modern diesel engines are also capable of running on straight (unmodified) vegetable oil (SVO) or waste grease, with some loss of power over petroleum diesel (West 2004). Numerous engine performance and emission tests have been conducted with SVO derived from many different sources, either as a standalone fuel or as a mixture with petroleum diesel (Fort and Blumberg 1982, Schlick et al. 1988, Hemmerlein et al. 1991, Goering et al. 1982).

The advantage of SVO as fuel is that a minimal amount of processing is required, which lowers the production costs of the fuel. The energy return for SVO, defined as energy output over the energy required to produce the fuel, will also be higher due to the avoidance of energy intensive downstream processing steps.

There are several disadvantages of using SVO as fuel. The first is that researchers have found that engine performance suffers, and that hydrocarbon and carbon monoxide emissions increase relative to petroleum diesel. Particulate emissions were also observed to be higher with SVO. However, the same studies found that nitrogen oxide (NOx) emissions were lower for SVO (Altin et al. 2001). On long-term tests, carbon deposits have been found in the combustion chamber, and sticky gum deposits have occurred in the fuel lines (Fort and Blumberg 1982). SVO also has a very high viscosity relative to most diesel fuels. This reduces its ability to flow, especially in cold weather. This characteristic may be compensated for by heating up the SVO, or by blending it with larger volumes of lower viscosity diesel fuels.

Conclusions

In order to understand the potential problems with biodiesel under cold weather conditions, it is important to understand that biodiesel is chemically different from petroleum or green diesel – and thus should not be expected to have the same chemical properties. Biodiesel is an ester, while petroleum and green diesel are hydrocarbons. The only reason it is called ‘diesel’ is that it can fuel a diesel engine. Likewise vegetable oil, butanol, and even ethanol blends could be called ‘diesels’, as each of these can be used to fuel a diesel engine.

Finally, it should also be noted that petroleum diesel is not immune from cold weather gelling. It is just that these problems don’t begin to occur until the temperatures are much lower than those at which biodiesel begins to gel. If extremely cold weather conditions are likely, then petroleum diesel is blended differently. More kerosene is put into the mixture, which is a lighter diesel (and has a shorter carbon chain length and is just a little heavier than gasoline) and is referred to as #1 diesel.

Footnotes

1. Lipids are oils obtained from recently living biomass. Examples are soybean oil, rapeseed oil, palm oil, and animal fats. Petroleum is obtained from ancient biomass and will be specifically referred to as ‘crude oil’ or the corresponding product ‘petroleum diesel.’

2. Methanol is usually produced from natural gas, although some is commercially produced from light petroleum products or from coal. Methanol therefore represents a significant – but often overlooked – fossil fuel input into the biodiesel process.

3. The cetane number is a measure of the ignition quality of diesel fuel based on ignition delay in a compression ignition engine. The ignition delay is the time between the start of the injection and the ignition. Higher cetane numbers mean shorter ignition delays and better ignition quality.

4. The cloud point is the temperature at which the fuel becomes cloudy due to the precipitation of wax. The pour point is the lowest temperature at which the fuel will still freely flow.

5. Hydrogen is produced almost exclusively from natural gas.

6. Companies actively involved in developing Fischer-Tropsch technology include Shell, operating a GTL facility in Bintulu, Malaysia since 1993; Sasol, with CTL and GTL experience in South Africa; and ConocoPhillips and Syntroleum, both with GTL demonstration plants in Oklahoma.

References

Altin, R., Cetinkaya S., & Yucesu, H.S. (2001). The potential of using vegetable oil fuels as fuel for Diesel engines. Energy Convers. Manage. 42, 529–538.

Arena, B.; Holmgren, J.; Marinangeli, R.; Marker, T.; McCall, M.; Petri, J.; Czernik, S.; Elliot, D.; & Shonnard, D. (2006, September). Opportunities for Biorenewables in Petroleum Refineries (Paper presented at the Rio Oil & Gas Expo and Conference, Instituto Braserileiro de Petroleo e Gas).

ConocoPhillips. (2007). ConocoPhillips and Tyson Foods Announce Strategic Alliance To Produce Next Generation Renewable Diesel Fuel. Retrieved July 21, 2007 from the ConocoPhillips corporate web site: http://www.conocophillips.com/newsroom/news_releases/2007+News+Releases/041607.htm

EIA, Energy Information Administration. (2006). Annual Energy Outlook 2006. DOE/EIA-0383, 57-58.

EPA, U.S. Environmental Protection Agency. (2002). A Comprehensive Analysis of Biodiesel Impacts on Exhaust Emissions. EPA420-P-02-001.

Fort, E. F. & Blumberg, P. N. (1982). Performance and durability of a turbocharged diesel fueled with cottonseed oil blends. (Paper presented at the International Conference on Plant and Vegetable Oils as Fuel, ASAE).

Goering C.E., Schwab, A. Dougherty, M. Pryde, M. & Heakin, A. (1981). Fuel properties of eleven vegetable oils. (Paper presented at the American Society of Agricultural Engineers meeting, Chicago, IL, USA).

Hodge, C. (2006). Chemistry and Emissions of NExBTL. (Presented at the University of California, Davis). Retrieved July 21, 2007 from http://bioenergy.ucdavis.edu/materials/NExBTL%20Enviro%20Benefits%20of%20paraffins.pdf

Hemmerlein M., Korte V., & Richter HS. (1991). Performance, exhaust emission and durability of modern diesel engines running on rapeseed oil. SAE Paper 910848.

Kinast, J. NREL, National Renewable Energy Laboratory. (2003). Production of Biodiesels from Multiple Feed-stocks and Properties of Biodiesels and Biodiesel/Diesel Blends. NREL/SR-510-31460.

Knothe, G. (2001). Historical perspectives on vegetable oil-based diesel fuels. INFORM 12 (11), 1103–7.

Ledford, H. (2006). Liquid fuel synthesis: Making it up as you go along. Nature 444, 677 – 678.

Neste Oil Corporation. (2007). Neste Oil inaugurates new diesel line and biodiesel plant at Porvoo. Retrieved July 21, 2007 from http://www.nesteoil.com/default.asp?path=1,41,540,1259,1260,7439,8400

NREL, National Renewable Energy Laboratory. (2006). Biodiesel and Other Renewable Diesel Fuels, NREL/FS-510-40419 Sheehan, J. NREL, National Renewable Energy Laboratory. (1998). An Overview of Biodiesel and Petroleum Diesel Life Cycles, NREL/TP-580-24772.

Schlick M. L., Hanna, M. A., & Schinstock, J. L. (1988). Soybean and sunflower oil performance in diesel engine. ASAE 31 (5).

Van Gerpen, J. (1996). Cetane Number Testing of Biodiesel. (Paper presented at the Third Liquid Fuel Conference: Liquid Fuel and Industrial Products from Renewable Resources, St. Joseph, MI).

West, T. (2004). The Vegetable-Oil Alternative. [Electronic version]. Car and Driver. Retrieved June 28, 2007 from http://www.caranddriver.com/article.asp?section_id=4&article_id=7818

Book Chapter Outline

While I have posted extended excerpts from my book chapter, I covered quite a bit more material in there. Here is the full chapter outline:

Renewable Diesel by Robert Rapier

1. The Diesel Engine

2. Ecological Limits

3. Straight Vegetable Oil (SVO)

4. Biodiesel

4.1.1. Definition/Production Process

4.1.2. Fuel Characteristics

4.1.3. Energy Return

4.1.4. Glycerin Byproduct

5. Green Diesel

5.1.1. Definition/Production

5.1.1.1. Hydroprocessing

5.1.1.2. BTL – Gasification/Fischer-Tropsch

6. Feedstocks

6.1.1. Soybean Oil

6.1.2. Palm Oil

6.1.3. Rapeseed Oil

6.1.4. Jatropha

6.1.5. Algae

6.1.6. Animal Fats

6.1.7. Waste Biomass

7. Conclusions

8. Conversion Factors and Calculations

8.1. Conversion Factors

8.2. Calculations

9. References

January 17, 2009 Posted by | biodiesel, biomass gasification, btl, Choren, ConocoPhillips, green diesel, Neste, renewable diesel | 34 Comments

The Lowdown on Miscanthus

Now that Blogger has determined that I am in fact a real person (see this note for an explanation), I am back in business. I notice the Barack Obama is now in favor of my proposal for allowing drilling and using that to fund alternative energy. Just glad I could help. 🙂 Call me if you need an energy secretary who detests politics and doesn’t respond to direction very well. More on that proposal in a later post, but first there was some topical alternative energy news from a couple of days ago.

A new report from researchers at the University of Illinois suggests that using Miscanthus as a feedstock for cellulosic ethanol production would be far superior to switchgrass:

Miscanthus can meet U.S. biofuels goal using less land than corn or switchgrass

Using corn or switchgrass to produce enough ethanol to offset 20 percent of gasoline use – a current White House goal – would take 25 percent of current U.S. cropland out of food production, the researchers report. Getting the same amount of ethanol from Miscanthus would require only 9.3 percent of current agricultural acreage.

“What we’ve found with Miscanthus is that the amount of biomass generated each year would allow us to produce about 2 1/2 times the amount of ethanol we can produce per acre of corn,” said crop sciences professor Stephen P. Long, who led the study.

In trials across Illinois, switchgrass, a perennial grass which, like Miscanthus, requires fewer chemical and mechanical inputs than corn, produced only about as much ethanol feedstock per acre as corn, Long said.

One finding that I felt was significant:

“One of the criticisms of using any biomass as a biofuel source is it has been claimed that plants are not very efficient – about 0.1 percent efficiency of conversion of sunlight into biomass,” Long said. “What we show here is on average Miscanthus is in fact about 1 percent efficient, so about 1 percent of sunlight ends up as biomass.”

That’s pretty good solar capture for biomass. It is far short of the efficiency of solar cells, but you have a built in storage mechanism – the primary weakness of solar power.

So what’s the catch? Seems like there is always a catch, doesn’t it? The catch is that it is still highly energy intensive to turn this biomass into ethanol. You have energy inputs in growing and harvesting the biomass, getting it to the ethanol plant, converting the cellulose to sugars, fermenting the sugars to ethanol, and then purifying the highly dilute broth to fuel-grade ethanol. That is of course the conventional cellulosic route, and as I have argued before I do not believe this route will ever be commecially viable. The chemistry and physics are strongly aligned against you, which is why we have spent over 40 years failing to crack this nut. That doesn’t mean that companies won’t try to commercialize. They are trying. I just don’t think they will be commercially viable, any more than I think a company is going to cure the common cold in the next 3 years.

Biomass gasification is another story. While the capital costs are still very high, in the long run you may be able to justify growing something like Miscanthus for a gasification plant to produce ethanol, methanol, or diesel. First, though, there is a lot of available waste biomass that could be utilized. Use the waste that is currently rotting or just being burned, and then let’s debate whether or not to dedicate good cropland to growing fuel.

August 2, 2008 Posted by | Barack Obama, biomass gasification, btl, cellulosic ethanol, miscanthus, switchgrass | 26 Comments

Visit to New Choren BTL Plant

Figure 1. Choren BTL Production Process. (Source: Choren)

Introduction

I had to dig way back in my Gmail archives to figure out how it was that I first interacted with Choren. I had written several articles on biomass gasification in 2006, and when I announced that I would be moving to Scotland in early 2007, I received an e-mail from Dr. David Henson at Choren. David, at that time in Business Development at Choren and now the President of Choren USA, said he had been reading the blog, and he extended an invitation to visit the biomass-to-liquids (BTL) plant that Choren was building in Freiberg, Germany.

While I tentatively planned to visit several times while I was living in Scotland, it wasn’t until I recently moved to the Netherlands that I was actually able to make the visit. So here is some background information on BTL, followed by the trip report from my visit on April 18th, 2008 (the day after German Chancellor Angela Merkel and Rob Routs from Shell visited for the inauguration of the facility).

BTL Background

I have written a number of articles on biomass gasification. However, let’s review. Biomass gasification takes biomass – ideally some sort of waste (and I understand that the term “waste” can be contentious) plant material – and partially burns the material with a controlled amount of oxygen to produce carbon monoxide and hydrogen (synthesis gas, or syngas). One of the often overlooked benefits of the thermochemical approach over fermentation is that it can be used to produce chemicals, synthetic natural gas, or electricity – and from a wide range of feedstocks. There are many different variations of how the gasification process is done, and I will delve into the specifics of what Choren is doing in the next section.

Once you have produced syngas, you can go a number of different directions. You can burn the syngas to produce combined heat and power (this has some cleanliness and efficiency advantages over directly burning the biomass), produce methanol, ethanol (Range Fuels, Coskata, Syntec), mixed alcohols (Standard Alcohol, Power Ecalene Fuels), or hydrocarbons like diesel via the Fischer-Tropsch process (FT). This latter approach is what Choren is doing. The diesel they are producing is not biodiesel, but “green diesel” as I have described in this essay (scroll down to the “renewable diesel” section).

To my knowledge no other company in the world is as far along as Choren is in producing diesel (and maybe any liquid fuel) from gasifying biomass. Whereas Range Fuels is currently building a plant (and the schedule for that is already slipping), and Coskata is building a much smaller demonstration plant, Choren has been piloting their technology since 1998, and their new plant is mechanically complete. (Yet Choren – funded largely by private investors – has been pretty low-key, issuing a fraction of the press releases of some of the other biofuel companies).

Choren’s Process

The Choren process (incidentally, Choren’s name comes from Carbon, hydrogen, oxygen, and renewable) starts off by feeding biomass into a low-temperature gasifier (about 500 degrees C). The purpose of this step is to remove volatile components that will form tars at higher temperatures. What remains in the gasifier is called char, and is fed into the high temperature gasifier.

Figure 2. Choren Gasification Process. (Source: Choren)

The volatile components are mixed with oxygen and steam and also fed into the high temperature gasifier where temperatures are around 1400 degrees C. Under these conditions, the volatile components are broken down into syngas. The char is first pulverized, and then blown into the bottom of the high-temperature gasifier. The gas that exits the high-temperature gasifier is cooled, generating steam in the process that is used for power generation. The gas is then further treated (filtered and scrubbed), and it is ready for the Fischer-Tropsch process. You can see an animation of the entire process here.

The gasification section of the plant has been in operation since 2004, proving the scale up of the design. Since 2005, the FT section of the plant has been under construction and is now mechanically complete.

I won’t go into detail on the FT process. That technology has been around for almost 100 years, and is best-known as the process by which Germany produced their fuel from coal in World War II. Shell – a world leader in FT technology – provided the FT for the Choren plant. If you are interested in learning more about Shell FT, you can read here about the 15 years of experience they have gained from their gas-to-liquids (GTL) plant in Bintulu, Malaysia. (In addition to providing the FT technology, Shell is also an investor in Choren).

The Plant Tour

It was difficult to find the place, and I got to brush up on my German a couple of times when I had to ask for directions. But finally we (I was with a colleague) found the place and met up with David. He started off with an introductory slide show in which he walked us through the process. One of the more interesting comments he made was that the potential production of their second generation product (dubbed SunDiesel®) is up to 3 times the production of first generation fuels. A third party analysis of various biofuels may be found here, at the Fachagentur fur Nachwachsenden Rohstoffe (FNR). This agency is essentially the German Renewable Energy Department. Detailed information on various BTL platforms can be found here.

Figure 3. Choren BTL Plant in Freiberg, Germany. (Source: Choren)

The new Choren plant, utilizes forest residue and waste wood and will take in 68,000 tons of biomass per year and produce 18 million liters of diesel and 45 MW of power. One thing David mentioned that too many in this business don’t seem to get is “You know, biomass just isn’t very energy dense.” Therein lies the source of a lot of people’s misconceptions about rapidly scaling up biomass to replace petroleum. The energy density is problematic to say that least – and this poses big logistical challenges.

We finally got to walk around the plant, and they have done a really nice job. Everything was brand new, and the design was well-thought out and well-engineered. This was not like a typical dirty, old refinery or ethanol plant I have walked through before: This plant was a Cadillac. Of course it’s a Cadillac yet to be driven, but it sure was a pretty picture. Here are some facts about the plant, courtesy of Choren:

Maximum production: 18 million litres of BTL p.a (= the annual requirement of about 15,000 cars)
Biomass requirement: About 65,000 tonnes of wood (dry matter) p.a.
Raw materials: Forest residue and waste timber
Supply is secure for several years
Investment: About €100 million
Technical details: 31.5 km pipelines, 57 km electrical cables,
5,000 fittings, 5,000 measuring signals,
60 pumps, 181 containers and reactors
45 MWth output
Partners: SHELL, Daimler and Volkwagon
Synthesis/hydrocracking partner: Shell

Of particular interest was the material handling piece, as this is a major cost factor in driving up the capital costs in a BTL plant. We traced out how the material comes into the plant, and how the flows of volatiles and char come off of the low-temperature gasifier. The one piece we didn’t really look at was the FT back end, but then again I have seen those before.

So, where do things stand, and what’s next? From the Choren site:

Over 150 suppliers and around 50 assembly companies, including many from the region, were involved in the building of the Beta plant. CHOREN designed and manufactured 180 main components itself. Over 600 companies had been involved in the development of the Carbo-V® technology. By April 2008 around 800,000 man-hours have been utilized in development and assembly, and the overall number of employees almost doubled.

In the coming months 113 sub-systems in 26 main operating units will be started up individually then in sequence. Around 1,200 steps will be needed for the commissioning of these systems, which in themselves consist of several sub-steps. A highly-complex process, which, not unusually for plants of this complexity, will take 8 to 12 months. CHOREN will receive valuable support for this from Shell.

What’s the Catch?

Capital costs for BTL are still pretty high. On the other hand, Choren’s costs were sunk at a much lower capital cost. Oil at $120/bbl should help them out quite a bit – provided they have a pretty good contract on their biomass. I have no doubt that they will be successful from a technical standpoint. They have a lot of experience on the gasification piece, having piloted it since the 90’s. Shell has many years of experience on the back-end FT piece. No doubt there will be some unexpected bumps as they commission the plant; after all it is a first of its kind and speaking from experience issues will come up. But they have a lot of engineers on staff, and I don’t think they will find any show-stoppers.

There are those who insist that using biomass for fuels can never be sustainable – so there are likely to be critics on that front. However, I disagree with this. There are a number of biomass sources that are true waste, and biomass can be grown sustainably. On the other hand, it can also be used to strip-mine the soil. Like most things, there are right ways and wrong ways to go about it. Biofuels have a part to play. But it would be foolish to try to completely replace petroleum with biofuels. That would require unsustainable practices. Incidentally, Choren has a life-cycle-analysis (LCA) on their process. Highlights can be seen here.

Short-term, I don’t know that this plant will be large enough to be profitable. I don’t think that’s the primary purpose; I think proving the technology for future plants is the purpose. In the longer-term, even though I am a fan of electrifying our transportation options, we will always have a demand for liquid fuel. Choren is trailblazing in an area that I believe will supply our liquid fuel in the future. The only question is, “How far off is that future?”

Additional Reading Material

Brochures and lectures for downloading may be found on Choren’s site here.

May 3, 2008 Posted by | biomass, biomass gasification, btl, Choren, green diesel | 41 Comments