Advanced Wood Combustion: Rekindling Wood Energy in America

Opened in February 2009, the new biomass power plant at Vermont's Middlebury College is expected to burn 20,000 tons of wood chips each year to provide heat and electricity for the campus.

The plant uses an "advanced wood combustion" system. Such plants hold great potential to save energy, cut costs, and even fight global warming, a March 2009 study says.

Photograph by Brett Simison, courtesy Middlebury College

Daniel Richter is professor of soils and forest ecology at Duke University and Director of Graduate Studies for Duke’s interdepartmental University Program in Ecology. His research investigates forest sustainability, biogeochemistry, interactions of soil and forests with the wider environment, and global soil change.

Below are excerpts from an article he wrote recently for Renewable Energy World.com about advanced wood combustion (AWC) and its promise for helping understand the intertwining of the carbon cycle and combustion - and how we can efficiently tap that energy for fuels, power, steam, and heat.

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Rekindling Wood Energy in America - Renewable Energy World

One of the largest sources of renewable energy available today is one of the oldest, that is direct combustion of wood. Recent European developments in advanced wood combustion (AWC, defined as automated, high-efficiency wood-fired energy systems with strict air pollution control) have wood supplying thermal and electrical energy cleanly and reliably to thousands of communities in Europe and increasingly in North America. AWC minimizes air pollutants including fossil greenhouse gases.

AWC is so clean and safe that AWC systems are commonly deployed in the midst of picture-perfect European towns and villages. Because AWC systems can be developed in community-sized increments of 0.1 to 20 MWth, they can be managed to meet community needs and not overwhelm the productivity of local woodsheds.

Wood in the United States is several-fold less expensive per unit of energy compared with natural gas or heating oil ($2 to 5 per GJ vs $7 to 10 per GJ for recent USA prices of natural gas and heating oil). If properly deployed, AWC systems can not only affordably supply clean and renewable energy, AWC can add value to the forest itself, promote community development, and support local employment and rural and municipal economies. AWC can complement other renewable energy resources as well.

It is now time for AWC and renewable thermal energy sources to take center stage in North American energy deliberations. Not only can wood safely and affordably supply energy, but wood can teach us much about energy in general, energy-use efficiency, and sustainability itself.

No one renewable will solve our energy crisis, not solar, not wind, not wood. But recent multi-agency estimates indicate that AWC can sustainably supply at least 5% of the nation’s currently inefficient energy consumption without impacting forests that are protected for environmental, social, or economic reasons. This is more energy that that stored in our Strategic Petroleum Reserve, more than what all American hydro-power plants produce in a year, and slightly more than half of the electric energy produced annually by the entire nuclear industry.

Wood is abundant but is far too valuable to inefficiently burn. Resource policy questions should turn on how to encourage wood-energy efficiency, community development and sustainability, and how to avoid extracting wood from the forest like coal from a mine.

SunOpta goes global with steam explosion biomass pre-treatment

Abengoa's Spanish facility for converting cereal straw to ethanol.

SunOpta Inc. is leading the development and commercial deployment of cellulosic feedstock pre-treatment for the production of ethanol. Their steam explosion technology will help developers preprocess cellulosic biomass feedstock of various kinds to produce ethanol.

The globally diverse projects involve diverse feedstock - woodchips (in Japan and Canada), corn stover (in China), sugar cane bagasse (in Louisiana, U.S.A.), and wheat straw (in Spain).

SunOpta’s Staketech Division is a world leader in the preparation, pretreatment, steam explosion and extraction of value added compounds from plant biomass material. In steam explosion, biomass fiber are exposed to a high pressure steam (typically 200-450 psig) for 1 to 10 minutes. The resulting product is then explosively discharged to an atmospheric pressure.

Batch steam explosion processing is almost 75-years-old. Batch processing, however, had some limitations, and was difficult to optimize. One of SunOpta’s breakthroughs was the development of a continuous steam explosion process that supports a higher processing temperature and reduces the residence time. The process greatly reduces and in many cases eliminates the chemicals associated with current industrial practice, according to the company. - Green Car Congress

They have also announced a deal with China Resources Alcohol Corporation to help them produce cellulosic ethanol in large quantites from corn stover:

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Sunopta Updates Current Cellulosic Ethanol Projects

China Resources Alcohol Corporation (CRAC)

CRAC has announced their intention to construct sufficient cellulosic ethanol facilities to generate 330 million gallons of ethanol by 2012. SunOpta provided its patented systems and technology to CRAC in September 2006 and the plant began production of ethanol from local corn stover in October 2006. This facility is reported to be the first cellulosic ethanol production facility operational in the People's Republic of China. The SunOpta system is currently operating on a continuous basis and steps are currently being taken to scale the SunOpta process up to full commercial levels for use in future plants in China.

China has committed $5 billion to cellulosic ethanol production and recently announced that they would allow no further increase in ethanol production from starch (corn), due to the needs for starch as food. China's announcement illustrates the "Food vs. Fuel" issue, which continues to be a key driver for cellulosic ethanol worldwide, together with concerns regarding the impact of the world's "addiction to oil" on the environment and energy security.


technorati BIOblog, BIOconversion, bioenergy, biofuels, ethanol, pretreatment, cellulosic

Black Liquor Gasification Technology Attracts Volvo Investment

Green Car Congress has run an article about an investment Volvo is making to help speed up the development of renewable fuels for the heavy vehicle industry.

They cite a Volvo Technology Transfer announcement and a report on the process developed by Chemrec AB of Sweden entitled Technical and Commercial Feasibility Study of Black Liquor Gasification with Methanol/DME Production as Motor Fuels for Automotive Uses—BLGMF.

Apparently their high-temperature gasification plant has recorded more than 1,100 hours of operating time producing syngas from black liquor.

Below is a snippet of the Green Car Congress article:

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Volvo Invests in Black Liquor Gasification Company

Volvo Technology Transfer AB is investing in Chemrec AB, a company that has developed a technology for gasification of black liquor, a residual product from the pulp industry.

Chemrec has shown that there is an efficient process for converting biomass into renewable fuels. The Volvo Group has no intention of becoming a fuel supplier but wishes instead to continue to conduct engine development on a broad front. On the other hand, we do want to participate in the development of new processes for the production of alternative fuels.
—Anders Brännström, President of Volvo Technology Transfer

Using gasification rather than incineration to dispose of the black liquor creates a number of by-products including synthesis gas. With this synthesis gas it is possible to utilize known techniques to produce a range of vehicle fuels such as methanol, DME (dimethyl ether), Fischer-Tropsch synthetic diesel and hydrogen gas.


technorati BIOblog, BIOstock, biomass, forestry, gasification

Low heat gasification converts woody biostock to energy

The thermal process of gasification is one way to break down the bonds of cellulosic feedstock into syngas (primarily CO and H2). Some processes, like plasma arc, uses extremely high heat to "vaporize" the biostock.

Here is an announcement from Germany about a company that has been getting very promising results from gasifying at a lower heat level. They claim, based on experiments with woody biomass, that the lower heat level enables the process to be applicable to a greater range of biostock, including wet forestry waste.

While commercial-scalability is always an issue, such advancements bring the vision of decentralized, blended feedstock, continuous flow bioconversion ever closer.

Here is a brief of the original article I found at Biopact. Thank goodness someone there can interpret German!

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German consortium tests new biomass gasification technology, obtains record hydrogen yield

The 'Zentrum für Sonnenenergie- und Wasserstoff-Forschung' (ZSW) in Baden-Württemberg, Germany, announces that it has developed a new gasification technology for the production of an energy rich gas from biomass that can be used for the generation of electricy and heat, but also for the production of biohydrogen, biomethane and a series of next-generation synthetic liquid biofuels.

The innovation at the ZSW concentrates on the water vapour gasification of biomass in the presence of a CO2 absorbent. The technology is based on an innovative step in a process called 'Absorption Enhanced Reforming' (AER), which was developed in cooperation with the University of Stuttgart and other European partners. During the gasification process, solid biomass is converted into a hydrogen-rich and carbon-oxide-poor fuel gas with a low tar content by means of integrated gas conditioning. Compared to other gasification processes, the AER technique yields gas with a much higher hydrogen content; pilot tests showed yields of up to 70% hydrogen, an unprecedented level.

The integrated gasification-cogeneration plant uses woody biomass as a feedstock. But, compared to conventional gasification methods, the AER technique considerably reduces the temperatures required for the gasification of biomass. This not only reduces the amount of energy needed to drive the process, it also allows for a much broader range of feedstocks to be used, including wet biomass. Large waste-streams from the agroforestry industry now become available: from grass and straw residues with low ash melting points, which weren't useable until now, to wet wood (leaves, shoots).

Scientists set sights on biomass to reduce fossil fuel dependence

This news release was posted 1/26/06 by Imperial College London. The alliance described includes the Oak Ridge National Laboratory which is clearly interested in the development of technology that can convert biomass into cellulosic ethanol. Efforts in this release refer to biomass feedstock involving the complete use of individual crops and a variety of different crops with the objective being the production of a variety of products including fuel, heat, and power using minimal amounts of non-renewable fuels.

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Scientists set sights on biomass to reduce fossil fuel dependence
Using plants rather than oil or coal to produce fuels and chemicals could play an essential role in reducing the world's dependence on fossil fuels, according to a group of scientists from the UK and the USA writing today in the journal Science.

The scientists from Imperial College London, Georgia Tech and Oak Ridge National Laboratory have evaluated the scientific and technological potential of a future based on renewable plant matter and biological material such as trees, grasses, agricultural crops, known as biomass. Their conclusions form the basis of a strategic alliance between the three institutions, the AtlantIC Alliance.

Today's paper describes the scientific challenges of creating a facility to process all the components of biomass. Such a facility would make a range of fuels, foods, chemicals, animal feeds, materials, heat and power in proportions that would give maximum value with minimum waste.

The scientists believe that efficient refining of biomass will be vital for producing renewable products with reduced carbon emissions. Biofuels and biomaterials are derived from plants which take carbon dioxide from the atmosphere as they grow. Their net contribution to the addition of greenhouse gases can be very small if minimal non-renewable energy is used when processing them into useful material or energy products.

Dr Charlotte Williams , from Imperial's Department of Chemistry and one of the authors of the paper, said: "We're looking at a future for biomass where we use the entire plant and produce a range of different materials from it.

"Biomass has a completely different molecular structure compared with hydrocarbons from oil. That means we'll need to develop new techniques so that we can transform plant material into everything from specialty, high value products such as perfumes and plastics to higher volume products such as fuels."

Imperial hopes that the partnership with Georgia Tech and Oak Ridge will combine their complementary areas of expertise and examine the critical issues from alternative angles. The project has been given a major boost by the award of a UK Office of Science and Technology grant to develop the alliance, backed up by internal funding from each of the partners.

Professor Richard Templer , Head of Imperial's Department of Chemistry, said: " No one institution is going to cover all the aspects and issues in this transition from a fossil resource-based present to a bio-based future. This partnership will increase the range of our scientific capacity. It will also enable us to evaluate the scientific and technological possibilities for the bio-based future from different perspectives, and in respect to the different potential for applications in the UK, USA and more widely, for example in developing economies."

FRANCE: Converting Woody Biomass into Ethanol

Achieving the dual goals of waste minimization and ethanol production is the objective of a new pilot project collaboration being undertaken in France. Wherever there are forests, paper mills, and logging there will be ample supplies of waste woody biomass that needs to be dealt with. In this scenario, Genencor enzyme technology will be applied to the minimization of milling process residue.

Here are excerpts from a Renewable Energy Access report. A press release from Genecor is also available online.


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This Week in the Ethanol Business
from Renewable Energy Access

Over in France this week it was announced that Genencor International, a subsidiary of Danisco A/S, will participate in a research consortium to develop economic ethanol production from paper pulp with help from the French forest products industry. The 1.2 million Euros [USD$1.5 million] project will deliver a baseline study of the technical and economic results of a small pilot plant installed at a pulp mill with a focus on waste minimization of the milling process.

"France is one of the leaders in the forest product industry and in related technical applications research," said Jean-Claude Pommier, Executive President of the Strategic Committee at the Institut du Pin -- Universite de Bordeaux. "We believe adding a biorefinery capacity to the paper pulp industry will be a sustainable innovation that will have broad impact."

Genencor will provide its advanced biomass cellulases and application expertise to optimize the enzymatic hydrolysis of various paper-pulp samples provided by Tembec and the Pine Institute. Tembec will analyze the economics to evaluate the system for commercial deployment by the pulp industry. INSA's Laboratory for Biotechnology and Bioprocessing will provide fermentation expertise The Pine Institute will share its expertise in pulping and handling, and in lignocellulose analysis and characterization.


technorati bioenergy, Genencor, ethanol, feedstock, biomass, France, enzyme, wood