zondag 24 juli 2011

Torrefaction: the Fuel of the Future

Posted by David Phillips on Wed, Jul 20, 2011 @ 10:54 AM

Plant cells, or biomass, represent the world’s largest renewable resource. Biomass is commonly plant matter specifically grown to generate electricity or produce heat, but can also include wood, waste, gas and alcohol fuels. The most conventional way it can be utilized relies on direct incineration, and the energy density of wood biomass can be increased through torrefaction.

Torrefaction is the thermochemical process that reduces the moisture content of wood biomass and increases its energy density, transforming it into a charred material resembling charcoal. This process reduces the mass of wood by up to 30%, resulting in a denser, higher-valued product.

Heyl & Patterson’s torrefaction equipment allows wood to retain up to 90% of its energy value. The energy-dense end result can be co-fired with coal in electric power plants, or used alone as a total replacement for coal.



Torrefaction ReactorTorrefied wood is made by mild pyrolysis of biomass within a torrefaction reactor, or rotary calciner, at temperatures of 500-600° F (260-320° C).
This removes water and low boiling-point organics and partially breaks down cellulose, hemicellulose and lignin. Reaction gases can be captured and used as a supplemental fuel source for the process itself. Torrefaction achieves a stable moisture content of about 3%, reduction of mass by 30%, retention of 90% of original energy content and removal of smoke producing agents. Torrefied wood has a heating value of approximately 10,000 BTU/lb.

States relying on coal can benefit by replacing some of that coal with the renewable energy of torrefied wood. States with the highest coal use have the greatest opportunity to implement positive change by substituting torrefied wood for some of their coal.

For more information about the equipment used for torrefaction,

To convert biomass pretreat with ammonia


MICHIGAN STATE (US) — Researchers have identified a potential pretreatment method that can make plant cellulose five times more digestible by enzymes that convert it into ethanol.

Presently, ethanol or other biofuels can only be produced in usable quantities if the biomass—corn leaves, stalks, or switchgrass—is pretreated with costly, potentially toxic chemicals in an energy-intensive process.

The new discovery, reported in the Journal of the American Chemical Society, could change that.

“What we’ve discovered is something like a cost-effective switch or a lever,” says Shishir Chundawat, postdoctoral researcher working with Bruce Dale, professor of chemical engineering and materials science at Michigan State University.

“By using an ammonia-based solvent, we were able to pull a lever and flip the entire cellulose crystal from one structure to another, one that’s much easier to break down.”

Biomass is a desirable renewable energy source because fermentable sugars within the cellulose network of plant cells can be extracted with enzymes and then converted into ethanol, but one of difficulties in the complicated is that cellulose tends to naturally orient itself into a sheet-like network of highly ordered, densely packed molecules.

These sheets stack upon themselves and bond tightly together due to strong interactions between molecules—somewhat like sheets of chicken wire stacked together and secured by loops of baling wire.

The stacking and bonding arrangement prevents enzymes from directly attacking most of the individual cellulose molecules and isolating the sugar chains within them.

During pretreatment, the water was removed and the ratio of ammonia was increased. As a result, the “baling wire” was replaced with loose thread, which made it vulnerable to conversion into sugars.

The end result is a potentially less costly and less energy intensive pretreatment regimen that makes the cellulose five times easier to attack.

The research was supported by the Great Lakes Bioenergy Research Center, a partnership between the University of Wisconsin and Michigan State.

More news from Michigan State University: http://news.msu.edu/

zaterdag 16 juli 2011

Graphite + water = the future of energy storage

Graphene sheets. Credit: Gengping Jiang

A combination of two ordinary materials – graphite and water – could produce energy storage systems that perform on par with lithium ion batteries, but recharge in a matter of seconds and have an almost indefinite lifespan.

Dr. Dan Li, of the Monash University Department of Materials Engineering, and his research team have been working with a material called graphene, which could form the basis of the next generation of ultrafast energy storage systems.

“Once we can properly manipulate this material, your iPhone, for example, could charge in a few seconds, or possibly faster.” said Dr. Li.

Graphene is the result of breaking down graphite, a cheap, readily available material commonly used in pencils, into layers one atom thick. In this form, it has remarkable properties.

Graphene is strong, chemically stable, an excellent conductor of electricity and, importantly, has an extremely high surface area.

Dr. Li said these qualities make graphene highly suitable for energy storage applications.

“The reason graphene isn’t being used everywhere is that these very thin sheets, when stacked into a usable macrostructure, immediately bond together, reforming graphite. When graphene restacks, most of the surface area is lost and it doesn’t behave like graphene anymore.”

Now, Dr. Li and his team have discovered the key to maintaining the remarkable properties of separate graphene sheets: water. Keeping graphene moist – in gel form – provides repulsive forces between the sheets and prevents re-stacking, making it ready for real-world application.

“The technique is very simple and can easily be scaled up. When we discovered it, we thought it was unbelievable. We’re taking two basic, inexpensive materials – water and graphite – and making this new nanomaterial with amazing properties,” said Dr. Li.

When used in energy devices, graphene gel significantly outperforms current carbon-based technology, both in terms of the amount of charge stored and how fast the charges can be delivered.

Dr. Li said the benefits of developing this new nanotechnology extend beyond consumer electronics.

“High-speed, reliable and cost-effective energy storage systems are critical for the future viability of electricity from renewable resources. These systems are also the key to large-scale adoption of electrical vehicles.

“Graphene gel is also showing promise for use in water purification membranes, biomedical devices and sensors.”

Provided by Monash University (news : web)

zondag 10 juli 2011

What Happened at Choren?

Posted by Robert Rapier on Friday, July 8, 2011

If you have not heard by now, Choren Industries has begun bankruptcy proceedings. For those who don’t know, since 2009 I have worked as the technology advisor for the major investor and primary funding source for Choren’s day-to-day operations. I have just returned from a visit to their plant in Freiberg, Germany. Due to the nature of my relationships with my employer and with Choren, I have to be guarded about what I say. To be clear, I do not work for Choren, and thus am not writing this as a Choren spokesman of any sort. But I do want to shed a bit more light on the situation.

First of all, to give a bit of background on Choren, the company’s roots go back to 1990. You can read their entire history on Choren’s website, but here are the highlights.

In 1998, Choren completed a pilot plant in Freiberg, Germany where they first produced methanol, and then later gas for electrical power and finally Fischer-Tropsch diesel. They tested a number of different feedstocks, including wood. That pilot plant ran from 1998 to 2004, and fuel was supplied to DaimlerChrysler and Volkswagen for fleet testing. Operating data were also being gathered to scale up the process.

Scale-up from the pilot plant was begun in 2003 at the Freiberg site. The gasifier would be scaled up from the pilot plant scale of 1 MWth to 45 MWth.

Shell’s Fischer-Tropsch technology was being used in the plant, and in August 2005 Shell became an investor in Choren. Daimler and Volkswagen later joined as investors. One of the consequences of Shell’s investment was that the plant — still under construction — had to be brought up to Shell’s safety standards. This was absolutely the right thing to do, but it caused a delay in the construction of the plant. Additional safety standards were implemented in the wake of the BP accident in Texas City that killed 15 people. Once more, this was the right thing to do, but caused delays and additional costs.

I personally became aware of Choren in 2007, and made a visit to their Freiberg plant in April 2008 (documented here) from my home at that time in the Netherlands. I was generally impressed with what they were doing, but I also raised questions around costs. My conclusion at that time was that they would eventually work out the kinks, but I thought it could take a while.

In 2009, I accepted a job as Chief Technology Officer for the man who is presently the largest shareholder of Choren (although to be clear, Choren is not his only investment). Before I accepted the job we had a lot of philosophical discussions about the difficulty of scaling up new technology, as well as the amount of time it takes to do so. We both shared a belief that oil prices are inevitably headed much higher, and in that case we both believed the Choren process would be ultimately economically viable.

Choren also started commissioning the gasification section in 2009. Thus began the long process of running for a period of time, and then shutting down and making adjustments. One of the biggest challenges in doing this is that there is no blueprint; nobody had run a gasifier like this at this scale on a biomass feedstock. So the plant had to work through many new technological challenges, and with a staff of 290 employees, the time it took to work through the issues was costly.

Because they had elected to forgo government funding, private investors have borne the development costs over the past few years. Several of those investors — including Shell — have exited at various points due to the time and cost it was taking to work out the technical issues. Ultimately, my employer was largely funding the ongoing operations of Choren from his pocket.

While the plant has made good progress, commissioning took far longer than expected. I had in fact warned that it would take at least a year to start up the plant once it was mechanically complete, but it was taking even longer than I expected. It finally got to the point that all investors decided to stop funding development, because all of the technical bugs had not been worked out. It wasn’t that there were any technical show-stoppers, it was just that the timing of how long it would take to work through the issues was uncertain.

Comparison to Range Fuels

It is inevitable that some will compare this situation to that of Range Fuels. However, there are some very important differences. First and foremost, I made it very clear that my criticisms of Range Fuels were never about failing. As my February 2010 essay on Range Fuels explicitly stated:

I want to make one thing crystal clear. I am not criticizing failure here. That is normal and expected. Failure is a part of what it takes to learn and move forward. What I am criticizing is the nature of the failure; that it was primarily because inexperienced people were making claims they shouldn’t have made, and taxpayers are going to get stuck with the bills. Personally, I have a problem with my tax dollars being squandered away by smooth-talking salesmen.

The fact is that most biofuel ventures based on new technology are going to fail. That is the nature of technology development. I have been involved now three times at some stage of scaling up a technology from the lab to a demonstration or commercial scale (four if I include a retrofit to an existing butanol unit that I piloted and ultimately commissioned at full scale). There are always challenges to be overcome, and often those challenges are show-stoppers. I know first hand the nature of these challenges, which is why it drives me crazy to hear people talk of producing fuel for $1 a gallon when they haven’t even built any sort of demonstration facility.

But some are more realistic about the risks of developing new technology, and therefore they don’t make wild, over-hyped claims that have little basis in reality. Choren had very little to say in the press, preferring to just work on their issues and attempt to get the technology running. That is one of the things I most admired about the company. For most of Range Fuels’ lifetime, they lived by the hyped-up press release, and made numerous claims that simply were not credible. On the back of those claims, they drew in and squandered a lot of taxpayer money.

While Choren chose to develop without the benefit of government money, acceptance of government money was also never the basis of my criticisms of Range (or other technology ventures). It is simply that when one does accept tax dollars, there needs to be some accountability for the hype. My criticisms are the circumstances under which funding via tax dollars is achieved; that is whether tax dollars are obtained essentially on the basis of groundless claims. In that case, companies are rewarded for hype, and the public is therefore bombarded by endless hype about solutions to our energy problems that never materialize. This is dangerous because it diminishes what I believe is a sense of urgency in developing real energy solutions. After all, where is the sense of urgency when 20 companies are all promising that they have the solution in hand? At least one of them has to be credible, right?

Where to Now?

At this point Choren is looking at several options so they can carry on with the process of commissioning the technology. At present I don’t know whether I will have any role in future Choren developments. I continue to believe that the long-term future of gasification is bright, and have cited on several occasions the fact that there are natural gas and coal gasification facilities around the world producing at scales of tens and even hundreds of thousands of barrels per day. So this is a technology that I view as far more scalable than most biofuel options that are on the table.

The catch is that it is more difficult to gasify biomass than it is to gasify natural gas or coal and produce syngas of a high enough quality for fuel synthesis. (Gasifying biomass isn’t hard really, but getting the right hydrogen/CO ratio and a high enough purity is where the challenges lie).

The Choren technology works, as demonstrated by years of run time at a smaller scale. But as I always warn people, scale-up issues can take some time to work through. When you first start up, there are a hundred little problems. You shut down, fix them, and restart to find there are still a dozen problems. You continue this process until all of the problems are solved, and then comes the challenge of running reliably for an extended period of time.

Sometimes, there are knockout factors as technologies are scaled up. That wasn’t the case here; as I said the gasifier has accumulated thousands of hours of run time at demonstration scale. Technical challenges have been solved in a systematic manner, and to date all of the challenges I have seen are solvable. The only questions are around the amount of time and money it will take, and whether either are in sufficient supply to allow the commissioning to finish.

woensdag 6 juli 2011

Productie van bio-ethanol voor de helft goedkoper

De productie van bio-ethanol kan dankzij een nieuw proces van TNO en partners voor de helft goedkoper. Naast de zetmeelfractie uit planten kunnen met dit proces ook de resterende stugge en houtachtige delen van planten worden benut. Door een slimme combinatie van bestaande en nieuwe technologieën wordt de kostprijs voor bio-ethanol hiermee teruggebracht van 45 eurocent tot circa 20-30 eurocent per liter.

Voor de productie van bio-ethanol haalt de industrie nu suikers uit de zetmeelfractie van gewassen als maïs, tarwe en suikerriet. Dat is niet alleen relatief duur maar ook de beschikbaarheid is beperkt om straks op grote schaal bio-ethanol te produceren. “We staan nog maar aan het begin van biobrandstoffentijdperk en de productiegrenzen komen al in zicht. Bio-ethanol uit maïs is de concurrentie met de voedingsindustrie al aangegaan,” aldus projectleider dr. ir. Johan van Groenestijn van TNO. Aan de toenemende vraag naar biobrandstoffen kan alleen worden voldaan door ook de suikers uit de stugge en houtachtige delen van planten (lignocellulose fractie) te benutten voor bio-ethanolproductie. Daarmee kunnen naast landbouwgewassen ook andere plantaardige materialen (biomassa), zoals rest- en snoeihout, gras, bladeren en stro, worden gebruikt. Deze zijn in grote hoeveelheden en tegen lage kosten beschikbaar.
Geconcentreerd zwavelzuur

De suikers in biomassa zitten echter stevig ‘verpakt’. Het is de kunst om deze effectief én zo goedkoop mogelijk vrij te maken (ontsluiten). Dat kan nu met het nieuwe proces waarin de biomassa wordt ontsloten met geconcentreerd zwavelzuur. Andere onderzoeksgroepen hopen hetzelfde te bereiken met toepassing van enzymen. Van Groenestijn: “Ontsluiten van suikers met geconcentreerd zwavelzuur is een beproefde methode uit de analytische chemie met een zeer hoge opbrengst. Enzymen komen er niet aan te pas. Dat is een groot voordeel, want enzymen zijn duur en voor de verschillende biomassa stromen zijn verschillende enzym cocktails nodig”. Zwavelzuur daarentegen is niet selectief en ontsluit elke soort biomassa, ook lastig verteerbaar houtafval.
Recyclen en hergebruiken van zwavelzuur

De robuustheid van dit omnivoor-proces is niet het enige wat het zo bijzonder maakt. Het ontwikkelde productieproces is een totaal plan voor gebruik van water, energie en hulpstoffen. Zo wordt door een slimme combinatie van een membraanunit én een afvalwaterzuiveringsunit het zwavelzuur voor 99,9% teruggewonnen. Dat is uniek. Bovendien wordt bij het recirculeren van zwavelzuur tegelijkertijd energie teruggewonnen dat direct in het proces wordt benut. Recyclen en hergebruiken, zowel van zwavelzuur, water als energie, maakt het proces duurzaam en energie- en kostenefficiënt. TNO voert inmiddels gesprekken met Noord-Europese en Zuid-Amerikaanse bedrijven om een eerste demonstratiefabriek te bouwen.

Two methods, one concept, all the benefits.

The new solution for more effectiveness.

KOMPOFERM® Hybrid integrates the process of dry and wet fermentation in one concept.
Residual waste now can be recycled simpler and more efficiently.
Initial case:

In many cases the treatment of the waste was previously very expensive and needs a lot of energy. Floating and sedimented material has to be separated which is very time intensive, there is only a limited increased input and it is very difficult to interfere in this closed system. In addition there is a high wearing of pumps and pipes. To minimize the complexity previously and to use effectively the high energy potential in the same time,KOMPOFERM® Hybrid developed by Eggersmann Anlagenbau combines the concepts of dry and wet fermentation.
The procedure

In the first stage, the input material must be sorted by mechanical treatment. The organic fine fraction afterwards is applied to the wet fermentation and the coarse fraction to the dry fermentation. This second step increases the spectrum of generating energy definitely.
The output of biogas is collected in a storage vessel and made available for recycling (third step). The digestates generated from both processes are compiled in a last step for after-treatment in a composting tunnel. Here the prepared digestate is provided for after- treatment.
The concept

With the method KOMPOFERM®- Hybrid the residues can be much disposed. The parallel running plants increase the output of biogas and allow a treatment well- directed of the arising digestate.This means double improvement.

Advantages are:
The costs of treatment are lower because previously there is less work by sorting.
The output of energy increases because it´s easier to condition the digestate.
The whole plant is used synergetically. Thus two methods are intregrated in one process of recycling.
The low wearout of components, the high robustness against the input- material, the high reliability and low maintenance costs convince the operator technically.

Bareau wint prijsvraag

Bareau en haar partners A. Hak en Norit/Xflow hebben met het concept “Autogenerative High Pressure Digestion (AHPD)” een subsidie gekregen om een proefproject te bouwen. AHPD is een nieuwe technologie waarmee op biologische wijze duurzame energie wordt teruggewonnen uit afvalwater. Bareau doet dit door anaërobe bacterieën in te zetten voor de productie van methaan en de opbouw van gasdruk uit organisch afval en afvalwater. Tegelijkertijd wordt drinkwater bespaard, kooldioxide afgescheiden en afvalwater gezuiverd zonder extern energiegebruik.

Geniaal concept

Drukgisting kan op bestaande waterzuiveringsinstallaties worden ingezet, maar beter nog decentraal in een woonwijk. Daar kan de Energie Prestatie Coefficient (EPC) met 10% worden verbeterd zonder invloed op de prijs van een huis. De Adviescommissie heeft de aanvragen op vier criteria beoordeeld; Bareau is op alle vier de criteria als beste uit de bus gekomen. De bijdrage op de gebieden “economisch perspectief”, “duurzaamheid” en “samenwerking en kennisoverdracht” zijn als “goed” beoordeeld. Het vierde criterium “technische of sociale innovatie” is als uitstekend beoordeeld met de woorden: “AHPD is een zeer vernieuwend en geniaal concept”.

De ontwikkelingen van de energieprijzen