Commercializing Innovation

The Biomass Pyrolysis

Spectrum

This report is an overview of the emerging technologies related to

torrefaction (bio-coal), slow pyrolysis (biocarbon/biochar), fast pyrolysis

(bio-oil) and biomass gasification (wood gas/syngas).

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FOR PUBLIC CIRCULATION

This report is for information purposes only, and its contents have

been prepared in good faith, derived from management's

knowledge and experience in the industry, as well as a variety of

third-party sources, such as independent industry publications,

government publications, company websites, and other publicly

available information, but no representation or warranty, expressed

or implied, is made by Sixth Element Sustainable Management or

its employees as to the accuracy, completeness, quality,

usefulness, or adequacy of the information and opinions in the

report, and Sixth Element Sustainable Management cannot take

any responsibility for the consequences of errors or omissions.

This material has been prepared for general circulation without

regard to any specific project and circumstances of persons who

receive it, and the information and opinions expressed in this

report may not be applicable to you. All rights reserved.

Prepared by: Gerald Kutney

© 2015 Gerald Kutney

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Bio of the Author:

Dr. Kutney, Ph.D. in chemistry, has participated in all aspects of innovation and technology commercialization -

especially related to torrefaction, pyrolysis, biochar, and biomass gasification - from the research laboratory to

patents to marketing to the executive suite. With two decades of executive experience in technology

commercialization with global corporations and entrepreneurial enterprises, he brings the innovation of research and

technology development, the financial discipline of big business, and the spirit of entrepreneurship to start-ups and

early-stage companies. He has extensive C-level experience, including strategic, operational, business development,

and administration leadership, business and financial planning and analysis, financing strategies, techno-commercial

evaluations and feasibility studies.

Bioenergy and Biofuels Director of Emerging Technologies and lead consultant in forestry bioenergy for the world’s largest

renewable fuels consulting group (Lee Enterprises Consulting)

Director of Biochar Ontario

Founded the LinkedIn group, Bioenergy Projects & Ventures

Executive of a biorefining group (bark boiler and CHP/IPP facilities; the largest cellulosic ethanol business

in North America; and bioproducts business with operations in Canada and France) of a major forest

products company

Executive of a biomass processing business in Canada

Executive of a pyrolysis venture with pilot facilities in Canada and South Africa

Authored over a dozen papers on pyrolysis presented at major bioenergy conferences (including the IEA

Bioenergy, International Bioenergy Conference, and CanBio)

Authored technical papers: Biomass Pyrolysis Spectrum and The State of Pyrolysis in Canada

Authored a study on the commercial status of over eight hundred and fifty pyrolysis firms

Authored a study on the global pyrolysis industry for the National Research Council Canada

Authored a study on the commercial status of wood-to-(drop-in) fuels for a European client

Mentored and edited the business plans for a biomass pellet venture in the U.S.

Mentored and edited the business/financial plans for a First Nation’s forestry venture in Canada

Audited the commercial preparedness of a pyrolysis venture for an IPO in Canada

Member of the expert panel on international standards for solid biofuels (wood/biomass pellets, torrefied

pellets and biochar briquettes) for ISO (TC 238)

Member of the expert panel on Canadian standards for solid biofuels for CSA

Climate Change and Policy Development Authored the peer-reviewed book Carbon Politics and the Failure of the Kyoto Protocol, which examines

the policy challenges for addressing climate change

Adjunct Professor & Part-time Instructor on fourth-year/graduate course on Climate Change, University of

Northern British Columbia – Environmental Science

Entrepreneurship and New Ventures Managing Director of own consulting venture

President of an emerging-technology venture

Chief Operating Officer with a new-technology venture

Approved consultant with the Business Development Bank of Canada (BDC, Entrepreneurs first)

MBA mentor & Start-up Garage mentor at the University of Ottawa

Entrepreneur mentor with Invest Ottawa

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Ashes denote that fire was;

Respect the grayish pile

For the departed creature’s sake

That hovered there awhile.

Fire exists the first in light,

And then consolidates,-

Only the chemist can disclose

Into what carbonates.

Emily Dickinson

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The Biomass Pyrolysis Spectrum

Temperature determines the state-of-matter yielded by pyrolysis:

torrefied, bio-oil, biochar

We use the pyrolysis of biomass every day without realizing it. The roasting and baking of foods are such processes.

Common pyrolysis reactors include toasters and barbecue grills. Caramel is produced by the pyrolysis of sugar, and

another popular product is roasted coffee.

Figure 1. Biomass pyrolysis spectrum.

Pyrolysis is the thermal decomposition of biomass occurring in the absence of oxygen. The products of biomass

pyrolysis (Figure 1) include torrefied biomass, biocarbon, bio-oil and producer gas (methane, hydrogen, carbon

monoxide and carbon dioxide). Depending on the thermal environment and the final temperature, pyrolysis will

yield mainly biocarbon at low temperatures, less than 450˚C, when the heating rate is relatively slow, and mainly

gases at high temperatures, greater than 600˚C, with rapid heating rates. At an intermediate temperature, but at

higher heating rates, the main product is bio-oil.

The choice of one technology over another is often determined by the state-of-matter of the biofuel that is desired.

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Torrefaction

The mildest pyrolysis process is torrefaction. During this reaction oxygen-rich compounds are volatilized from the

biomass, including non-condensables such as carbon dioxide (80%) and carbon monoxide, and condensables such as

water (60%), acetic acid (25%), methanol, formic acid and furaldehyde. These products mainly originate from

hemicellulose, which is decomposed in the process. Torrefied wood is thus mainly composed of cellulose and lignin.

Torrefaction reaction rates are highest in straw, followed by hardwoods and softwoods, but the final properties are

similar. The various reaction rates are attributed to the differing hemicellulose structures found in the different types

of biomass.

The torrefaction reaction begins at 200˚C, but the practical range is 250˚C to 280˚C. In the torrefaction process,

temperature is a more important factor than reaction time, which is typically 30 minutes or less. Care must be taken

not to go much higher in temperature as carbonization begins in the range of 280˚C to 300˚C. The temperature is

generally the major operational control parameter to determine the properties of the torrefied wood. Higher

temperatures generally lead to higher energy densities, but yields decline. An optimum control point is autothermal

operations where the energy of the volatiles is enough to supply the energy of the process.

When first invented, torrefied wood was often called “red charcoal” (charbon roux or Rothkohl) or “brown

charcoal.” The word torrefaction, itself, is derived from the French word “torrefier,” which means “to roast.”

Research on torrefaction began in France during the 1830s, and the self-binding property of torrefied wood was

known by the turn of the 20th century; for example a U.S. patent was issued in 1901 to Joshua Gardner on the

formation of briquettes of “partially-carbonized” sawdust. Another early American report of torrefaction was by

Cleburne Basore in his Fuel Briquettes from Southern Pine Sawdust in 1929.

Today, interest has switched from briquettes to pellets, through development by firms such as ECN and Topell

building the first torrefied wood pellet facility in Europe. Overall, when torrefied wood is pelletized, the physical

properties are improved:

The product is water-resistant: can be stored outdoors on a coal pile, and generally does not reabsorb

moisture after drying.

The fibrous nature is reduced and the grindability has been improved.

Energy density is higher than that of a wood pellet.

Bulk density is higher than that of a wood pellet, reducing transportation costs on an energy basis.

No binder is necessary to form the pellet.

Biological degradation is greatly reduced.

Various biomass feedstock can be utilized.

Uniform quality improves combustibility.

The targeted market for torrefied biomass is the coal-fired power sector. Torrefied wood is being used in Europe,

and in North America, where trials have recently been carried out at the GWF Power Systems’ Pittsburg, Calif.,

petcoke power plant and at the James River power station in Springfield, Mo.

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Figure 2. The rise in higher-energy density.

As one goes from a wood chip to a wood pellet to a torrefied pellet to a biocarbon briquette, the general chemical

and physical properties of the biomass are transformed more and more into a coal-like product. A generic technique

to illustrate the chemical properties of various fuels compared to coal is to plot the hydrogen-to-carbon ratio versus

the oxygen-to-carbon ratio of the fuel, which plot is called a Van Krevelen Diagram. The most obvious property is

the rise in higher-energy density (Figure 2).

0

5

10

15

20

25

30

Wood Chips Wood Pellet Torrefied Biocarbon

En

erg

y D

en

sit

y (

GJ

/te

)

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Carbonization

Above 300˚C, carbonization of biomass commences and the thermochemical reactions become exothermic (i.e.,

heat-generating), which drives the higher-temperature pyrolysis with no (or little) external energy being applied.

Biomass undergoes major chemical modifications at these higher temperatures.

Carbonization mimics coalification whereby nature converts plant matter into coal. Whereas coalification takes 300

million years, carbonization converts plant matter into charcoal, which has an energy density similar to bituminous

coal, in 300 minutes (or less).

As the temperature of pyrolysis increases, mass is lost as oxygen-rich volatiles and the energy density of the

remaining solid matter rises. Chemically, the percentage of carbon rises as the oxygen declines. The more carbon

(and hydrogen) and the less oxygen that a material contains, the greater its energy density.

The higher energy density of charcoal compared to wood was one reason for its use in early industrial applications,

such as blacksmithing, glassmaking and the iron industry. Currently, global production of charcoal is nearly 50

million tonnes.

A new market for charcoal is emerging as a renewable coal replacement for electricity generation. For industrial

markets, the product is called biocarbon instead of charcoal; the latter term is reserved for recreational use.

Biocarbon has another role to play in the fight against climate change as it can be used to sequester carbon in the

soil. Biochar is the agricultural application of biocarbon. When applied to soil, biochar acts as an agricultural

catalyst by promoting plant growth, but is not consumed. Since it is a catalyst, its benefits continue for generations

to come without further addition. The biochar holds nutrients and fertilizers longer in the soil and provides other

benefits encouraging plant growth. At the same time, the carbon has been sequestered or the carbon of the original

biomass has been fixed and will not naturally return its carbon into the atmosphere. Biochar is one of the most

promising agricultural breakthroughs since the discovery of fertilizers.

Producing biocarbon is achieved through the process known as slow pyrolysis. Heating the material very quickly, or

fast pyrolysis, produces bio-oil, with biocarbon as a byproduct.

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Gasification

Gasification is a pyrolysis process that creates producer gas, a low-energy gas containing mainly carbon monoxide

and hydrogen (methane may also be present, especially at lower gasification temperatures). A pioneer in biomass

gasification was Philippe Lebon (or Le Bon) D’Humbersin (1767-1804). In 1801, he put on a light demonstration in

Paris that was fuelled by the gasification of wood. Unfortunately, the young entrepreneur was murdered three years

later, before he could develop the technology further.

Biomass gasification technologies can be divided into three categories: fixed-bed, fluidized-bed and entrained-flow.

Fixed-bed gasifiers use a simple grate system whereby the process begins with a combustion zone that produces

carbon dioxide and water; these products are then passed through a reducing zone to produce carbon monoxide and

hydrogen. Fixed-bed reactors are usually utilized in systems of less than 5 MW. There are two types of fixed-bed

gasifiers – updraft and downdraft – each of which has its advantages. Updraft gasifiers are a simple design but are

prone to higher release of tars and other impurities. Downdraft gasifiers, while reducing the tar content, require a

drier biomass feed and lose some of the biocarbon with the ash.

Fluidized-bed gasifiers are structurally more complex than fixed-bed, but generally produce a cleaner and more

uniform producer gas. These facilities are usually in the range of five to 100 MW. Most larger-scale biomass

gasification facilities have utilized fluidized-bed reactors, especially bubbling, which uses an inert heat-transfer

medium such as sand.

Entrained-flow gasifiers are generally for larger units in the range of 50 to 500 MW and are the most efficient of the

three technologies. These processes can utilize two types of reactants, either air or steam.

Gasification has advantages over direct combustion or incineration of biomass, the most important of which is that

the emissions are generally an order of magnitude lower than the emissions from an incinerator. As well, a more

consistent fuel is sent to the boiler and ash is not carried directly into the boiler.

An important route to synthetic liquid fuels is related to the gasification process. The products of gasification,

carbon monoxide and hydrogen, are called syngas when not contaminated by tars. Syngas can be converted into a

variety of liquid fuels by the platform technology known as Fischer-Tropsch or FT technology. In 1925, Franz

Fischer and Hans Tropsch discovered that syngas could be catalytically combined to form hydrocarbons (i.e., oil).

Similar catalytic reactions can convert syngas into methanol or ethanol.

Conclusion

Although the products of the pyrolysis technologies vary greatly, they are all founded on a similar basic technology,

the heating of biomass in a low-oxygen atmosphere. The separation between them depends on the temperature of the

reaction. While the basic technologies have been known for over a century, only a few biomass-based facilities have

been constructed, as the economics of these processes often cannot compete against those of fossil fuels. The result

is that few plants have been constructed and fewer still have been a commercial success.

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Sixth Element Sustainable Management is a "boutique" consulting firm specializing in commercializing

innovation, and evaluating the business preparedness and commercial potential of technology developers and their

projects. We provide executive management services for inventors, entrepreneurs, investors, and public sector

agencies in new technology, start-ups and early-stage ventures. Services are directly provided by the Managing

Director of Sixth Element Sustainable Management, Gerald Kutney, Ph.D. in chemistry.

Venture success depends more on management than the technology itself. Dr. Kutney has participated in all aspects

of innovation and technology commercialization, from the research laboratory to patents to marketing to the

executive suite. With two decades of executive experience in technology commercialization with global

corporations and entrepreneurial enterprises, he brings the innovation of research and technology development, the

financial discipline of big business, and the spirit of entrepreneurship to start-ups and early-stage companies.

Visit our website at www.6esm.com and contact us to discuss options and services: gkutney@6esm.com.