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DENSIFIED LOGS REDUCE THE IMPACT OF RESIDENTIAL WOOD HEATING
DENSIFIED LOGS REDUCE THE IMPACT OF RESIDENTIAL WOOD HEATING
Table of Content
ABSTRACT
HIGHLIGHTS
PROJECT OBJECTIVES / PHASES
BACKGROUND
TECHNOLOGY
RESULTS
POTENTIAL AND LIMITATIONS
INFORMATION
ABSTRACT
Because wood burning is a major source of fine particle emissions, particular attention is given to residential wood heating. Recy-Clone inc. has carried out a project that demonstrates the environmental and energy efficiency of fuel made from densified wood residue.
Tests conducted under the independent supervision of Forintek Canada Corp. showed that this fuel produces 50% less fine-particle emissions than conventional logs.
As well, the logs are made from wood residue that would otherwise end up in a landfill.
Densified wood logs have many other advantages: the product is uniform, easy to store and energy efficient.
HIGHLIGHTS
Technology
Process uses wood residue from the primary and secondary wood processing industries
Thermal extrusion process allows the lignin in the wood to act as a natural binder
No petroleum-based, chemical or other additives
Environment and Energy
Reuses industrial wastes
Uses a renewable energy source
Reduces fine particle emissions from wood burning (33% to 58%)
Improves fuel quality and energy efficiency (20% to 35%)
Reduces the use of virgin resources for residential heating (every tonne of densified wood is equivalent to 12 mature trees)
Cost-effectiveness
May reduce wood consumption because of the greater energy potential
PROJECT OBJECTIVES/PHASES
The objective of the project was to validate technically and environmentally the burning of logs made from densified wood residue in residential woodstoves. The tests were carried out using the standard Environmental Protection Agency (EPA) protocol, one EPA-certified stove and one noncertified stove. The aim of the tests was primarily to:
Measure the rate of particle emission from the logs made from densified wood residue
Measure the rate of particle emission from conventional logs standardized in accordance with the EPA protocol
Compare the particle emission rates of the two types of logs
A supervised test using a control group of 20 people living on Montreal Island was also carried out in order to determine their perceptions of environmental issues related to heating with wood, their wood heating profile and their assessment of logs made from densified wood residue compared with conventional logs.
BACKGROUND
Fine particles 2.5 µm and smaller (PM2.5) are one of the key components of smog. Links have also been established between fine particles and increased respiratory problems and premature deaths. Fine particles are therefore a concern not only for public health institutions, but also for environmental departments and agencies.
Residential wood heating contributes significantly to PM10 and PM2.5 emissions. According to Environment Canada’s inventory of primary air contaminants for year 2000, home heating with wood was the fourthlargest source of PM2.5 emissions in Canada. If we exclude open sources, wood heating would be the largest source of pollutants, generating almost 28% of all fine particles.
TECHNOLOGY
Logs made from densified wood residue are manufactured using an extrusion process and are composed of hardwood residue with a controlled particle size and moisture content. The material fed into the extruder must have a moisture content of approximately 12% or less, and a maximum particle size of 1.2 to 3 mm.
The raw material is then compacted and pressurized at a temperature range of 200 °C to 300 °C. The naturally occurring lignin in the wood acts as a binder, allowing the residue to form a log as it cools off when it comes out of the mould.
The finished product is an octagonal log about 7.5 cm in diameter. The hollow core allows the log to burn more efficiently. The product comes out of the extruder in a continuous piece and is mechanically sawn into logs between 20 and 30 cm long (depending on the client’s needs). The final product has an estimated density of 1.2 (density of water = 1.0) and a low moisture content (between 4% and 6%).
This method of producing logs made from densified wood residue requires no petroleum-based, chemical or other additives.
LuminoTox uses multienzyme complexes that have been isolated from plant extracts, providing an easy to use and rapid technique that can be employed in the field. It is therefore a practical and cost effective tool for the environmental management of municipal, agricultural, agri-food and industrial effluents. LuminoTox is also an effective means of monitoring the quality and toxicity of drinking, surface and underground water supplies.
1 - ex.: Sawmill
2 - ex.: Furniture fabrication
RESULTS
In the course of this project, three tests were conducted to measure fine particle emissions and other secondary combustion parameters of logs made from densified wood residue. The tests were done using two types of common residential woodstoves. One was certified in accordance with the U.S. EPA standard, the other was not.
For purposes of comparison, an additional test was done using standardized conventional logs in an uncertified woodstove.
Previous results of certification tests carried out in the Intertek laboratory using standardized conventional logs were also used as a reference for the combustion test performed in the certified stove.
The tests showed that densified wood logs produce fewer fine particles when burned. When the logs were burned in the certified stove, the emission rate was almost 58% lower than the rate for the conventional logs. The particle emissions rate dropped from 8.5 g/h to 3.6 g/h.
When the uncertified stove was used, the reduction in fine particle emissions was approximately 30%. The tests also showed that the smoke from burning densified wood residue logs takes 25% less time to dissipate.
The residual ash rate was also lower, at approximately 0.7% of the initial mass. The rate for conventional logs generally ranges between 1% and 4%.
The supervised test, carried out over a two weeks period, also showed that the users appreciated the densified wood residue logs as much as the traditional logs, while confirming its higher properties in term of cleanliness, reduction of smoke and residual ashes, and speed of heat releases.
1- The protocol in EPA Method 28 (method for effectiveness and emissions tests) was used for each burn test.
2 - Closed-damper tests. The results using conventional logs were obtained by the Intertek laboratory in an earlier test using an appliance in the same series.
3 - Open-damper tests.
N/A: Not Available
POTENTIAL AND LIMITATIONS
Potential
Densified wood residue logs:
Are an alternative to conventional logs
Are more energy efficient
Reduce the environmental impact of residential wood heating, especially in densely populated areas
Produce fewer fine particles and ash than conventional logs when burned
Create fewer handling and storage problems (dampness, dust, mildew, vermin etc.)
Are a tangible and accessible way of mitigating the problems associated with air quality and management of waste from the primary and secondary wood processing industries
Limitations
The success of densified wood residue logs depends on how they are received and accepted by consumers and distributors
The cost might be slightly higher than the cost of conventional logs. The associate advantages of the densified wood residue log such as the energy efficiency, ashes reduction and storage facilities are nonetheless to be dismissed.
INFORMATION
This data sheet was prepared based of the results of a project to demonstrate the environmental and energy efficiency of densified wood residue logs. The project was carried out with financial support from Environment Canada and the Agence de l’efficacité énergétique du Québec, technical support from Forintek Canada Corp. and Stove Builder International (SBI), and the cooperation of the City of Montreal.
For more information, please contact :
Recy-Clone inc.
Marco Gagnon
President
Tel. : (450) 430-6725
E-mail: Recy-clone@bellnet.ca
Environment Canada
Air Issues
André Germain
Tel.: (514) 496-7673
E-mail: Andre.Germain@ec.gc.ca
or
Élie Fédida
Tel. : (514) 496-1364
E-mail: Elie.Fedida@ec.gc.ca
Agence de l'efficacité énergétique du Québec
Douglas Labelle, ing.
Président
Tel. : (418) 627-6379
E-mail: Douglas.Labelle@aee.gouv.qc.ca
City of Montreal
Infrastructures, Transportation and Environment
Ronald Poissant, P. Eng.
Tel. : (514) 280-4434
E-mail: rpoissant@ville.montreal.qc.ca
ENVIRONMENT
Technological Innovation
Technological Innovation data sheets, published by Environment Canada, are intended for all firms, industries, organizations and individuals interested in new environmental technologies. Their purpose is to disseminate the results of technology development and demonstration projects carried out in the following sectors: wastewater, atmospheric emissions, contaminated soil, waste management, hazardous waste, agri-environment, and innovative tools and processes.
Data sheets may be obtained from:
Environment Canada
Innovation, Monitoring and Industrial Sectors Section
105 McGill Street, 4th floor
Montréal, Quebec H2Y 2E7
Tel.: (514) 496-6851
1 800-463-4311
Publications available on the Web site of Environment Canada in the Publications section: http://www.ec.gc.ca/dpe
Production:
Julie Leduc
Writer:
Pierre Dessureault
Reviewers:
Élie Fédida
André Germain
Douglas Labelle
Jean-René Michaud
Ronald Poissant
Graphic Design:
Lacroix O'Connor Lacroix
Printer:
Impressions IntraMédia
Published by Authority of the Minister of the Environment
© Her Majesty the Queen in Right of Canada, 2005
Cat. No: En153-113/55-2005E
ISSN: 1712-0209
ISBN: 0-662-39644-8
February 2005
Cette fiche est également disponible en français sous le titre : Bûches densifiées réduisant l'impact du chauffage résidentiel au bois
