We cannot claim that it is the most efficient of pyrolysing systems (16% efficiency or 6:1), but it gets the job done with minimal capital outlay. We plan to convert 30 hectares of mixed exotic invaders from Australasia Acacia mearnsii (black wattle) and Acacia decurrens (green wattle) on a private farmers’ land back to pristine grassland. We have 5 kilns on the mountain and each kiln produces about 80 to 100 kg (220 lb) of charcoal per day. The felled timber is prepared and stacked in piles measuring 1 m (L) x 1 m (W) x 1 m (H) or approximately 500 kg (1102 lb) per pile. We have a staff compliment of about ten dedicated individuals.

Below are some late afternoon vistas of the farm following a thunderstorm, blessing the area with much needed precipitation. The wattle areas can be seen in the last two photos. This is a very beautiful and picturesque farm and with the invasive wattle eventually removed it will be a polished diamond indeed, as seen through the eyes of the first inhabitants of the area.

This blog post aims to provide the reader with some background on charcoal stove usage as well as charcoal burn characteristics.  Vuthisa developed a unique charcoal stove, able to extract and burn harmful Carbon Monoxide gases inherent to all types of charcoal.

Jiko charcoal stove

We discovered that charcoal use by households is not a new concept and constitutes the primary urban fuel in most of Africa and it is estimated (2003) that approximately 250 million people cook with charcoal. The prevailing tendency in household fuel usage has been to move away from wood fuel towards charcoal for reasons ranging from smokeless burn, ease of use, easy storage, no insect infestation, no need to air-dry, cost effective to transport and high temperature burn.

Several intervention studies have also shown that switching from wood to charcoal can substantially reduce respiratory infections, which may also account for the move over to charcoal. Much of the world’s charcoal feedstock is not plantation wood and the unsustainable harvesting of biomass result in widespread deforestation, thereby handing charcoal its bad reputation. In our context, countries like South Africa (and most developing countries) with well managed commercial plantations and exotic invaders however can provide a sustainable supply of charcoal for household end-use applications. In our opinion improved charcoal stoves should only be sold to communities if the charcoals are produced from carbonised invasive alien vegetation or managed commercial plantations. See our Welcome post in this regard. The manufacturing process is also very polluting and wasteful and there is a serious need of improved charcoal kilns. Join the Portable Kiln Google Group, which I started in order to improve the efficiency of this design or for more information visit this information page and join our design challenge.

More modern fuels such as paraffin- and LP Gas are becoming more popular than fuel wood for cooking and space-heating, but have led to several deaths due to accidental shack fires or lethal gas leaks. Burning charcoal conventionally inside a home is a hazardous and potentially fateful undertaking due to the dangers of Carbon Monoxide (CO) poisoning. I highly recommend Carbon Monoxide Poisoning – A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References.

Some experts agree however that if issues of concern related to CO such as ventilation and education can be successfully addressed, the widespread implementation of improved charcoal cook stoves should be considered. Traditional charcoal burning stoves such as the metal and ceramic Jiko and Loketto were designed to retail cheaply and provide durability during extended usage, which they do, but failed to address the problem of Carbon Monoxide (CO) poisoning once the occupants go to sleep.

Vuthisa decided to investigate charcoal burning by developing and field testing many prototypes. Feedback from stove users indicated that charcoal can be very abrasive on metal surfaces in direct contact with flames and due to the rapid heating and cooling tendencies of a charcoal fire. Charcoal burned in coal or fuelwood stoves reduced the lifetime of these stoves significantly. Refractory ceramics (and low-density clay bricks) offered the best results as it insulates the fuel from the stove body, but also allows combustion temperatures to rise above 600°C for complete combustion of volatiles.

We discovered that the volatile Carbon Monoxide (CO), a fuel in its own right should instead of being vented off be re-combined with pre-heated Oxygen (O2) from the air in a process termed Gasification. This results in a LP gas-like flame, venting harmless CO2. The process occurs spontaneously and the charcoal fuel batch will burn out in its entirety within 90 minutes from lighting the stove. Depletion of Oxygen levels in a poorly ventilated room can therefore not occur and CO issuance build-up remains below Health and Safety limits.

Best Burn Method

We found it is possible to light the stove indoors with minimal particulate issuance by top lighting the stove using kindling (visit woodheat.org to see the advantages of the top down lighting technique). We monitored CO build-up inside the room with a Draeger X-am 5000 CO monitor, maintaining adequate ventilation. The maximum CO ppm (parts per million) recorded was 30 ppm over a 1.5 hour period. Once the occupants gets exposed to levels of around 200 ppm for extended periods they will experience nausea, headaches and vomiting. Higher levels of around 1000 ppm for example, have far more serious consequences, including falling into a coma and never waking up.

Back to charcoal burning: After the stove is lit, temperatures will continue to rise inside the chamber and more coals will start to combust, although the top layer will be protected by a so-called “pyrolysis wind”. Primary air is drawn up the combustion chamber by virtue of the internal chimney. The stack length has been optimized to control the draft to combine 6 parts air to 1 part fuel, with the secondary air supplying the remaining 6 parts air to resultant 1 part producer gas. Pre-heated secondary air (drawn in along with the primary air before splitting off) will spontaneously interject into the area above the charcoal particles and mix with a constantly escalating supply of producer gas (CO and other volatiles) from the coals. Stoichiometric air/fuel ratio is achieved after approximately 8 to 10 minutes following start-up and gasification commences, the visual clue being a blue flame front forming off the burn plate (catalyst). Most charcoals contain approximately 20 to 30% producer gas, i.e. is not vented during the charcoal manufacturing process and the stove will deplete these supplies in approximately 30 to 40 minutes. The resultant ‘coke’ will also partially gasify and burn to ash over the remaining 30 to 45 minutes. The stove can be operated on a maximum fuel load of 500 grams of charcoal for approximately 1.5 hours. It can use as little as 150 grams of charcoal, sufficient to cook a small meal or for boiling approximately 1 L of water. A full patent was granted in 2006 and is still in force. Double click on video image below to see charcoal stove in action.

We’re not the only ones thinking charcoal gasification has potential in the developing wolrd. See this publication by Ulrich Graf called Low Cost Charcoal Gasifiers for Rural Energy Supply (GTZ, 1994, 49 p.). The publication demonstrates to interested laypersons and experts the conditions and applications under which small charcoal gasifiers can be one option for development within a range of simple energy technologies.

It is also possible to “pipe off” volatiles produced by a charcoal gasifier to run a generator as can be seen in this example: http://www.youtube.com/watch?v=-zKjiYQwSJ0&feature=player_embedded

Or watch this video below showing some of our Bioenergylist discussion group members experimenting with a burner attachment. Double click on the still image below to start video.

Durability

Vuthisa partnered up with the University of KwaZulu-Natal’s Ceramic Department in Pietermaritzburg to develop insulated fire bricks. We have made significant progress with our insulated fire bricks, with the mixture consisting of mainly Al2 O3, Fe2 O3, SiO2, CaO, grog and a light-colored refractory clay. An external supplier was contracted to supply the pre-mixed clay in powdered form. The cost per cubic metre is low and lends itself perfectly for this application. The density is lower than what can be achieved with clay mixes that contained sawdust. Our most recent bricks achieved a density of approximately 0.5 g/cm3 which qualifies it as an extremely lightweight yet durable refractory brick. The bricks and the ash filtering base are then joined together via a specially formulated paste-like cement that can withstand temperatures of up to 1300°C to form a hex shaped combustion chamber.

We also have a monolithic, precast, pre-fired, silicon-hardened, fibrous, refractory ceramic sleeve (not replicable outside South Africa) with a density factor of around 0.5 g/cm3, which is being used in our outdoor camping stove.

Dissemination

Stove programs in South Africa have a poor track record (Wood as a source of fuel in South Africa, MV Gandar, 1983). Attention is all too often focused on fuel efficiency, economics and ease of construction at the expense of the socio-cultural environment. It is therefore important to slowly introduce a new stove concept to the target community to test their acceptance of it, but also to demonstrate the advantages that owning such a stove offers. It will be vital to do product acceptance trials in the proposed project implementation area and adopting a successful dissemination technique will take the stove project towards success through inception to maturation. Extension workers should record cooking technique and fuel usage information. The information must be interpreted to fine tune the design specific to the needs of the community.

In summary

It is hoped that by informing a wider audience, strategies can be formulated to improve charcoal making and charcoal burning technologies.

Camping stove to create awareness

Our prototype portable charcoal camping stove aims to highlight the plight of millions of people cooking on inefficient and unsafe charcoal stoves. It is not for sale at this time. Kindly donate (on the sidebar to the right) to help us bring the stove to the market!

In line with creating awareness around issues concerning indoor air pollution, we also promote the clean-burning StoveTec Rocket stove. Click here for more information.

Enquiries welcome via our Contact us page or visit the News link from time to time for updates.

Dr. Larry Winiarski, now Technical Director of Aprovecho, began developing the Rocket stove in 1980 and invented the principles of the Rocket stove in 1982. The Winiarski Rocket stove’s simple design and use of common materials make it easily modified for optimal performance. In the last 29 years, variations of the Rocket stove have been built in over 20 countries. The Rocket elbow can be made from different materials such as sand/clay (Lorena), pumice/concrete, heavy steel pipe, 430 stainless steel or refractory ceramic. Find a comprehensive list of Websites, Videos, Downloads and Manufacturers at the bottom of this page with regards to building, using or purchasing a Rocket stove. Click here to go to References

What’s wrong with an open fire?

An open fire, as shown above, is often 90% efficient in turning wood into energy. But only a small proportion (10% to 40%), of the released energy makes it into the pot. Improving combustion efficiency does not appreciably help the stove to use less fuel. On the other hand, improving heat transfer efficiency to the pot makes a large difference. Improving the combustion efficiency is necessary to reduce smoke and harmful emissions that damage health. Improving heat transfer efficiency can significantly reduce fuel use. Fire is naturally good at its job, but pots are not as good at capturing heat because they are inefficient heat exchangers. In order to reduce emissions and fuel use, the stove designer’s job is to first clean up the fire and then force as much energy into the pot or griddle as possible. Both of these functions can be accomplished in a well engineered cooking stove and a Rocket stove. A Rocket stove is a type of stove combining the air-intake with the fuel-feed slot in an opening into the combustion chamber extending into an “internal chimney” before exiting through the vertical chambered heat exchanger.  Some models have the chimney located in a different location, drawing emission gases along a horizontal path (sometimes below cooking points) before exiting through the vertical chimney.

Click on image above to play GIF animation

Or download image here.

A Rocket stove is signified by ease of construction and simplicity of building materials while accepting small-diameter fuel such as twigs or small branches, yielding high combustion efficiency and directing the resultant heat most effectively. A Rocket stove achieves efficient combustion of the fuel at a high temperature by ensuring that there is a good air draft into the fire, controlled use of fuel, complete combustion of volatiles, and efficient use of the resultant heat.  As the fuel burns within the combustion chamber, convection draws in new air from below ensuring that any smoke from smoldering wood near to the fire is also drawn into the fire and up the chimney. The chimney should be insulated to maximize the temperature and improve combustion.  The design of the stove means that it can operate on about half as much fuel as a traditional open fire and can use smaller diameter wood. Some models can accept whole logs, with only the tips combusting. In horizontal feed magazines the fuel has to be pushed into the combustion chamber at regular intervals. The advantage of this system is that the heat output can be adjusted as required, but the disadvantage is that if left unattended the fire will extinguish.

Rocket stoves are usually insulated and some are raised up from the floor which reduces the danger of children burning themselves. For space heating purposes the heat is transferred to a heat store which can in some cases be part of the structure of the house itself. The exhaust gases then pass out of the building via the chimney. The use of a cooking hood is recommended as the hood and chimney combination does not influence the rate at which air is introduced to the fire. The “internal chimney” creates the optimum amount of draft for fuel-efficient combustion.

A Rocket stove’s main components are:

Fuel magazine: Into which the unburned fuel is placed and from where it feeds into the combustion chamber. The fuel magazine can be horizontal where additional fuel will be added manually or vertically for automatic feeding (gravity feed) of fuel. The fuel magazine can be simple steel piping or even ceramic pipe. Fuel shelves serve as the platform for the fuel that is used with the stove. This slightly raised platform makes it possible for air to flow over and under the fuel source.

Combustion chamber/Internal chimney: At the end of the fuel magazine where the wood is burned. Internal chimneys are mere extensions of the combustion chamber and may be constructed from a larger tin can to piping and provide the required draft to maintain the fire. The top of the combustion chamber/chimney serve as the support for the cooking area. Some Rocket stove designs have chimneys in a separate location to the combustion chamber.

Chimneys: Located above the combustion chamber or to one side or can be part of the hood extraction system.

Heat exchanger: To transfer the heat to where it is needed, i.e. the cooking pot. From the chimney the heat passes into a suitable heat exchanger to ensure the efficient use of the generated heat. For cooking purposes the design keeps the cooking vessel in contact with the fire over the largest possible surface area by use of a pot skirt to create a narrow channel which forces hot air and gas to flow along the bottom and sides of the cooking vessel. The pot is usually encompassed by a fixed or adjustable pot skirt. The pot skirt functions as a shield to force the emission gases to pass close to the container holding the food. The gap between the skirt and the pot is also known as the pot gap. The pot gap calculation is crucial to the performance of the stove and excel spreadsheets are usually used to calculate this gap.

Rocket stoves are found more commonly in third world countries where wood fuel sources are scarce but it has been introduced in the United States in recent years. Some of them are small for portability with insulation inside a double-walled design with a chamber for partial biomass gasification and additional mixing to increase power output and provide a cleaner, more complete burn. In some models, as the wood is converted to charcoal, it falls through a grate for later collection and carbon sequestration. Since the Rocket stove is a wood burning cooking stove, obtaining fuel while on a camping trip is easy. Unlike a campfire, the Rocket stove will function very well using small branches and limbs that tend to litter the floor of the woods. This means there is no need to chop larger sections of wood into smaller sections in order to feed the fire.

References:

Websites
http://en.wikipedia.org/wiki/Rocket_stove Definition of a Rocket stove
http://www.bioenergylists.org/stovesdoc/Still/Rocket%20Stove/Principles.html Larry Winiarski’s Rocket Stove Principles (Dean Still)
http://www.bioenergylists.org/stovesdoc/Design/Design.html Biomass Cookstove Design and Testing
http://www.ehow.com/how_2265305_build-winiarski-rocket-stove.html#ixzz1H5MC0jJa How to Build a Winiarski Rocket Stove
http://www.ehow.com/how_4507160_build-rocket-stove.html How to Build a Rocket Stove
http://www.ehow.com/how_6550436_make-rocket-stove-camping.html How to Build a Rocket Stove for Camping
http://www.rocketstove.org Where you go on the web to find (or to learn how to make) Rocket stoves that work (Peter Scott)
http://www.treehugger.com/files/2009/03/rocket-stoves.php Rocket Stoves: Build Your Own Ultra-Efficient Cook Stove (Video)
http://www.mnn.com/your-home/at-home/stories/rocket-stoves-tips-for-designing-your-own Rocket stoves: Tips for designing your own
http://www.rocketstoves.com/ Website of the Book Rocket Mass Heaters
http://www.pyroenergen.com/articles08/eco-rocket-stove.htm PYRO-Eco Stove for Cooking on Rural Areas (Junji Takano)
http://bioenergylists.org/en/taxonomy/term/ Rocket stoves (9 web pages)
http://www.appropedia.org/CCAT_rocket_stove Campus Center for Appropriate Technology (CAT) Rocket stove
http://www.squidoo.com/rocketstoves Rocket Stoves – Cool Name, Hot Stove
http://www.rootsimple.com/2007/11/our-rocket-stove.html Our Rocket Stove
http://solarcooking.wikia.com/wiki/Rocket_Stove Rocket stove
http://www.wonderhowto.com/how-to-build-and-understand-rocket-stove-331886/ How to build and understand a Rocket stove
http://mdulastove.wordpress.com/ Holey Roket (as in Rok+et) : a biomass briquette stove type by Rok Oblak
http://www.stoveteam.org/ Home to the Ecocina Rocket stove
http://vuthisa.com/news/rocket-stove/ Examples of Rocket stove installations in South Africa
http://www.meadowforge.co.uk/DK_rocket_stoves.htm The DK Rocket stove (UK)

Videos
http://www.youtube.com/watch?v=XSMR2ANIZ7E How to Make a 16 Brick Rocket Stove
http://www.youtube.com/watch?v=235m0EzZF4U DRTV Rocket Stoves
http://www.youtube.com/watch?v=LfKHVoCY2so 12 Rocket stove mass heaters – efficient wood heat
http://www.aprovecho.org/web-content/media/rocket/rocket.htm How to build a Rocket Stove
http://video.google.com/videoplay?docid=797446823830833401# How to make a Rocket stove by Vavrek
http://www.youtube.com/watch?gl=IE&hl=en-GB&v=eqUsUMlyIeQ Coffee can Rocket stove by Rich
http://www.youtube.com/watch?v=gO-vPyCShLg&feature=player_embedded#at=94 How to Make a Tin Can Rocket Stove by Larry Winiarski
http://www.rocketstove.org/index.php?option=com_content&task=view&id=42&Itemid=93 How to build an institutional Rocket stove – Part 1 to 8 by Peter Scott
http://www.youtube.com/watch?v=YIMi0DVDvqw&feature=player_embedded Build a Rocket stove by Aprovecho
http://www.youtube.com/watch?v=CsDjcv5vO4c&feature=related Operation of the StoveTec Combo Two Door Stove by Dean Still
http://www.richsoil.com/rocket-stove-mass-heater.jsp Rocket stove mass heater – website containing various instructional videos
http://www.youtube.com/watch?v=GmEiLMT56L0&feature=player_embedded Redneck Rocket Stove using cinder blocks
http://www.youtube.com/watch?v=vJ7WjwAqeX0 How to assemble special bricks into a Six Brick Rocket Stove with Ken Goyer by Aid Africa
http://www.youtube.com/watch?v=9uh2VExcdbY&feature=player_embedded#at=221 The principles of a Rocket stove and how to build one – Institutional type
http://mdulastove.wordpress.com/holey-rocket/holey-roket-making/ Holey Roket Making (as in Rok+et) by Rok Oblak
http://www.youtube.com/watch?v=2fmp23SdS2Y Ecocina step by step
http://youtu.be/9CM4K5K-TiI Happy Rocket stove users in South Africa
http://wn.com/Rocket_Stove_Workshop World News now hosts many YouTube videos on Rocket stoves

Downloads
http://stoves.bioenergylists.org/stovesdoc/apro/Institutional_Rocket.pdf The Institutional Rocket Stove Designed by Dr. Larry Winiarski
http://www.bioenergylists.org/stovesdoc/Pcia/Design%20Principles%20for%20Wood%20Burning%20Cookstoves.pdf Design Principles for Wood Burning Cook Stoves
http://stoves.bioenergylists.org/stovesdoc/Still/AprovechoPlans/Rocket%20Stove%20Design%20Guide.pdf Rocket stove design guide
http://www.bioenergylists.org/stovesdoc/Scott/malawi/Malawi%20Repor1.pdf (See page 9 for fire brick recipes) Introduction of Rocket Stove Technologies (Institutional stoves, Household stoves and insulative refractory bricks) Into Malawi, March- July 2004
http://stoves.bioenergylists.org/stovesdoc/Scott/malawi/Malawi_ReportAug05.pdf Malawi Report
Feb 1st – April 11th, 2005
http://stoves.bioenergylists.org/stovesdoc/apro/guide/HOUSEHOLD%20Stoves%20Construction%20Manual%20Nov%202004.pdf MINISTRY OF ENERGY AND MINERAL DEVELOPMENT Energy Advisory Project HOW TO BUILD THE IMPROVED HOUSEHOLD STOVES
http://www.rocketstove.org/images/stories/chimney%20tool/IRS%20Assembly%20Guide%2010%2027%202010%20new.pdf Institutional Rocket Stove (IRS) Assembly Guide Designed by Peter Scott
http://www.rocketstove.org/images/stories/chimney%20tool/IRS%20Calculation%20Sheet%2010%2026%202010.xls Pot gap calculation

Manufacturers
http://www.stovetec.net/us/index.php – StoveTec
http://www.envirofit.org/cookstoves.html – Envirofit
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330431124275
http://www.speedreading4kids.com/rocket3.htm
http://www.rocketstoves.org/
http://www.stockstorage.com/ – The Grover Rocket Stove
http://www.meadowforge.co.uk/DK_rocket_stoves.htm – The DK Rocket Stove

What is biochar and what is the difference between biochar and charcoal?

They are identical in many respects, but the telling difference is in how they are used.  Charcoal is used as a fuel.  Crushed charcoal mixed into soil as a soil amendment is biochar.

As a soil additive, biochar offers numerous potential benefits

Unlike fertilizers, biochar has an extremely long life in soils. Charcoal is carbon-rich and gives it the ability to persist in the soil indefinitely by not being susceptible to biological decay.  Biochar also attracts microbes and beneficial fungi, holds on to nutrients that are put into the soil. i.e. biochar works better the second and third year than it does the first.  One of the major challenges in agriculture is to make the nutrients in the soil available to the plant when the plant can benefit from them.  Fertilizers can often only be applied early in the growing season, before the crop canopy closes and field operations are no longer feasible.  Unfortunately, between the time the fertilizer is applied and the crop takes it up, fertilizers can be leached out of the soil by excess rainfall, consumed by weeds, or metabolized by microbial activity in the soil.  Biochar helps conserve plant nutrients by storing them within its matrix and making the nutrients available when the crop needs them.  This happens because of a property in biochar, certain clays, and soil organic matter known as Cation Exchange Capacity (CEC).  CEC is a measure of the capacity of biochar to retain ions, such as ammonium and potassium cations, in an exchangeable form that is available to plants.  CEC not only helps conserve the fertilizers added to the crop during the growing season, but also improves the ability of the soil to capture and retain nutrients from other sources available at other times.  For example at the end of the growing season crop residues are often left in fields to decompose.  When this organic matter decomposes, biochar captures some of the nutrients released, leaving those nutrients for the next growing season.

Biochar in soil also has the ability to hold moisture and save on irrigation costs.  Biochar modifies the soil’s performance by retaining moisture and making it available during periods of low precipitation and hot, dry soil conditions.  This is possible because biochars have very large internal surface areas – typically over 100 square metres per gram.  This internal surface area adsorbs moisture when water availability within the soil is high and releases it back into the soil when water availability is depressed.  Some may think that biochar being black in color would heat up in the sun, but biochar helps the soil stay moist even in full sunlight.  Biochar also has significant impacts on soil drainage.  Clay soils which are typically poorly aggregated are too tight and do not drain effectively.  Ineffective drainage results in extended periods of inadequate soil aeration.  Other soils, especially sandy soils may drain too efficiently.  Overly efficient drainage can shorten the benefit of periodic wetting.  In both cases, the addition of biochar compensates for the native soil deficiency in the following ways:

Clayey and poorly aggregated soils become less compacted and provide better aeration

Sandy soil acquire additional bulk moisture storage capacity

Biochar also makes a significant contribution to mycorrhiza by promoting microbe populations.  Mycorrhiza is a fungi that has a symbiotic relationship with plant roots and contribute to a healthy soil-plant nutrient exchange.  Biochar increases the availability of mycorrhiza by:

Detoxifying soil water by adsorbing compounds that inhibit microbe growth

Providing a  protective habitat for microbes

Improving soil moisture management in which mycorrhiza thrives

Biochar can mitigate climate change

By reducing consumption of fossil fuel and

Capturing CO2 and sequestering carbon in the soil

In a world dependent on fossil energy, it is easy to see the carbon capture benefits of biochar as offsets against current and future fossil fuel emissions.  Many scientists believe there is already an unsafe excess of carbon dioxide in the atmosphere, this obligates the nations that caused the excess to abate it.  It is notable that from the year 1850 to 2000, 34% of carbon dioxide emissions have been attributed to land clearing.  Therefore, in a sense, the first goal of biochar is to restore the carbon lost from the soil due to the past 150 years of agricultural practice.  After that, the particular durability of biochar will enable the build-up of more carbon in soils, with further fertility benefits as the existence of Terra preta soils have shown us.  Terra preta soils are fertile, black biochar-rich soil found in scattered tracts throughout the Amazon basin, also, the pre-Columbian civilization responsible for creating that soil, dating back to 450 to 8,000 B.C.  Charcoal has the potential to sequester gigatonnes of atmospheric carbon per annum, making it the most potent engine of atmospheric cleansing we possess.  Approximately 8 percent of all atmospheric CO2 is absorbed by plants each year. If just a small proportion of the carbon captured by plants can be pyrolysed and transformed into charcoal, humanity’s prospects will be much brighter, for this will buy us time as we struggle to make the transition to a low emissions economy.

How do you make biochar?

The production of charcoal and biochar has a common root.  Before fossil coal emerged during the Industrial Revolution (18th Century) the word coal meant charcoal – the black fuel made from wood.  The basis for all charcoal and biochar production is pyrolysis: essentially, breaking wood down into its chemical constituents by heat, with little or no oxygen.  We do not use the same archaic methods of yesteryear, with the development of cylindrical metal vessels and high temperature refractories.  Good biochar has high porosity, extensive micro-structure, and adsorption capacity that enable beneficial interactions between microbes, nutrients, and water in the soil.  The so-called 55/30, a simple closed retort, is popular with biochar enthusiasts.  In a typical configuration, the “55/30″ consists of a 55-gallon (200 litre) outer drum containing the fire around a 30-gallon (100 litre) inner drum acting as the enclosed retort.  A 30-gallon barrel, open at one end standing with the open end down on flat surface, makes a simple and serviceable closed retort.  Click here for a collection of all types of biochar making kilns: http://www.carbon-negative.us/Burners.htm

Vuthisa opted for the Portable Metal Kiln Method for biochar production, which differs from conventional open burn methods in five ways:

The steel plate is very thick and not only lasts longer than 55 gallon drums, but allows the contents of the kiln to “cook” in the absence of charcoal by means of a tight sealing lid

The drum can be made oval to fit in two sealable 55-gallon drums, yet also allow burning material to be added to heat the drums

Small sized feedstock, typically found in yard waste, such as twigs and branches are ideal for this system as it will not turn to ash, as with larger horizontal type kilns that can take up to 3 days to cool down, reducing small diameter feedstock to ash

Large quantities of biochar can be produced as opposed to the 55/30 type closed retort that produces small quantities

The kiln can be rolled long distances to adjacent feedstock piles without any difficulty, yet can still fit on the back of pickup trucks.  More information can be found here: http://www.vuthisa.com/biochar

Resources

http://biochar-books.com/The_Biochar_Revolution The Biochar Revolution – Transforming Agriculture & Environment – Edited by Paul Taylor

http://vuthisa.com/2009/11/14/make-charcoal-in-your-own-backyard/ Make charcoal in your own backyard

http://www.scribd.com/document_downloads/16916390?extension=pdf Biochar for Environmental Management: Science and Technology Edited By Johannes Lehmann and Stephen Joseph

http://www.mycorrhizae.com/ Mycorrhiza

http://www.carbon-negative.us/Burners.htm Biochar producing kilns

http://biochar.bioenergylists.org/ Biochar discussion list website

http://bioenergylists.org/ Improved Biomass Cooking Stoves

To obtain access to more URLs relating to the above subject matter (not for public viewing) send your request through to: http://vuthisa.com/contact-us/

http://za.linkedin.com/in/vuthisa

The stats helper monkeys at WordPress.com mulled over how this blog did in 2010, and here’s a high level summary of its overall blog health:

The Blog-Health-o-Meter™ reads This blog is on fire!.

Crunchy numbers

A Boeing 747-400 passenger jet can hold 416 passengers. This blog was viewed about 12,000 times in 2010. That’s about 29 full 747s.

In 2010, there were 5 new posts, growing the total archive of this blog to 10 posts. There were 300 pictures uploaded, taking up a total of 60mb. That’s about 6 pictures per week.

The busiest day of the year was December 16th with 162 views. The most popular post that day was Make charcoal in your own backyard.

Where did they come from?

The top referring sites in 2010 were terrapreta.bioenergylists.org, youtube.com, en.wordpress.com, search.conduit.com, and ahualoa.net.

Some visitors came searching, mostly for sketchup promo code 2010, charcoal kiln design, stovetec, how to make charcoal, and charcoal kiln plans.

Attractions in 2010

These are the posts and pages that got the most views in 2010.

Make charcoal in your own backyard November 2009
14 comments

Home June 2009
5 comments

Briquettes March 2010
5 comments

StoveTec January 2010
6 comments

Fuel briquettes saves trees and provides income generation for the poor March 2010
6 comments

The conference/workshop was facilitated by the Legacy Foundation (Oregon, USA) through funding from the McKnight Foundation of Minnesota. It is part of a three-year project backing environmental conservation in Africa. For more information on Fuel Briquettes, background to the technology and press construction manuals, kindly visit our Fuel Briquettes page. Participants arrived from Tanzania, Uganda, Kenya, Rwanda, Chad, Burkina Faso, Democratic Republic of Congo (DRC), South Africa and Botswana. The main aim of the conference is to create an African Briquette Producers Network so that new knowledge and improved recipes can be passed on to producers even if they are working in different regions. Over the next couple of weeks we will be highlighting some of the challenges facing briquetting groups, entrepreneurs and organizations alike in achieving successful transference of theoretical knowledge into practical know-how. This is no easy feat as there are many constraints and challenges facing briquette producers, such as obtaining presses or tools, many lack business skills, standardizing of briquette size and quality, packaging and marketing and end-use issues such as briquette combustion techniques.

Image courtesy of http://members.chello.nl/r.bouwman9/travelingtheworld.htm

Our presentation on Thursday (11th) intended to bring participants up to speed with rocket stove technologies as well as discussing air/fuel ratios to effect optimum stove performance. We had two stoves at the conference, namely the StoveTec wood rocket stove and the Vuthisa charcoal gasifying stove. Although the StoveTec was not originally designed to burn briquettes, it coped very well with smaller diameter- or broken up briquettes. The Vuthisa charcoal gasifying stove was lit on the final night of the conference to better showcase the blue flames that can be achieved through the optimal combustion of charcoal. The stove was lit using approximately 450g of lumped charcoal pieces kindly provided by the Olasiti Gardens’ kitchen staff. After approximately 45 minutes of operation, showcasing complete combustion and mesmerizing blue flames, briquettes consisting of agro-residues (and very little charcoal fines) were broken into pieces and inserted into the combustion chamber. The briquettes were quickly pyrolized into char without any smoke and the char-gas burn commenced shortly thereafter. We then donated the StoveTec to a grateful participant.

Below is a collage of photos taken by Peter Stanley, myself as well as other participants. Click on it to go to my Flickr slideshow. The Legacy Foundation will be bringing out their final report and we will be putting a link to it here in the next couple of weeks. Here is a link to press coverage of the conference.

More updates to follow…

**Update**

Final report by Legacy Foundation:

http://vuthisa.files.wordpress.com/2011/01/briquette_producers_conference.pdf

With more and more communities having access to the Internet it would make sense to create a facility through which they can order informative books to assist them in their day to day lives. Unfortunately limited bandwidth and a lack of color printers means that e-books often remain either unattainable or less than adequate for their needs. It is therefore refreshing to learn that Development Bookshop delivers books fresh off the printing press and in full color to ALL parts of the world. Vuthisa therefore supports the Development Bookshop and we created this page that can only be described as having a portal to your own online personal library. Development Bookshop is operated by Practical Action Publishing and offers a wide range of titles (over 1,500) on international development and related issues by various authors and publishers. Topics range from Agriculture and Food Security, Building and Construction, Disasters and Emergencies, Economic Development, Education, Energy, Environment, Climate and Sustainability, Indigenous Knowledge, Manufacturing to Micro-finance to name just a few.

They offer a full delivery service worldwide and each year, despatch over 20,000 books to more than 100 countries. I include some titles below to give an idea of what is available and could be considered my favorites. Happy reading!

We have added a new section at the bottom of our Bookshop page for new book titles relevant to sustainable living and environmental matters, not offered by Development Bookshop.

Is it better to burn wood or charcoal? Half the World’s population of nearly six billion people prepare their food and heat their homes with coal and the traditional biomass fuels of dung, crop residues, wood and charcoal  (Inheriting the world: The atlas of children’s health and the environment, by Bruce Gordon, Richard Mackay and Eva Rehfuess, WHO 2004). In China, India and Sub Saharan Africa, up to 80% of urban households use biomass fuels for cooking. Wood fuel usage is the most predominant with charcoal a close second. What is their respective influence on global warming? Sorry, but this post will not attempt to discuss this complex issue, because the reality is that for most people struggling with energy security, saving the environment is not exactly high on their list. The following paragraphs will instead focus briefly on the burning characteristics of wood and charcoal, because in many cases availability and affordability of the fuel type will dictate which fuel type is being used.

Typically wood has an energy value of between 14 and 18 MJ/kg when burned. Charcoal has an energy value of around 29 MJ/kg, in other words charcoal burns hotter than wood, but when not insulated or not receiving sufficient air supply (including secondary air), the absence of flames or fast flowing CO2 gases will result in less efficient cooking due to a lower heat transfer efficiency (HTE). In other words with conventional charcoal burning (glowing embers) the pot will receive radiant and infrared heat, with the pot positioned close to the coals. Wood burning flames (especially from open fires) tend to ‘lick’ the pot and transfer heat more effectively, but contain products of incomplete combustion (PIC), also known as ‘particulates’, that are harmful to humans when inhaled. In many instances households cannot afford to purchase or install chimneys that remove the smoke. The flames (yellow colored) will also tend to blacken cooking pots. Indoor smoke inhalation gives rise to pneumonia and other respiratory infections – the biggest killer of children under five years of age. Indoor air pollution (IAP) is responsible for nearly half of the more than 2 million deaths each year that are caused by acute respiratory infections (ARI). Good ventilation and improved cooking stoves can dramatically reduce children’s exposure to smoke. Vuthisa currently promotes the StoveTec stove which is very fuel efficient (conserves wood) and emits 70% less smoke. Visit http://vuthisa.com/news/stovetec for more information.

Charcoal is preferred over wood as a cooking fuel in many parts of the world because it does not produce smoke, is easier to transport and ready to use in a convenient dry- and broken-up form. Charcoal burning however produces large amounts of Carbon Monoxide (CO) which is harmful to humans when exposed to very high levels. Increasing air flow through the charcoal emits more CO, so if you don’t mix secondary air with the CO and insulate the fuelbed to raise temperatures to spontaneously combust that mix, you’re better off with a glowing ember burn. Most charcoal stoves (i.e. Ceramic Jiko) are not designed around this principle and won’t be much different to your barbecue, whereby you vent all the gases first and then cook on the glowing embers. There is anecdotal evidence that family members have succumbed to CO poisoning, but families using charcoal are very aware usually of it’s dangers and allow for adequate ventilation. Why is CO harmful to humans? Let me explain: The effect of high levels of exposure to CO can be lethal, but even low levels of exposure can have harmful effects. CO diffuses rapidly via blood vessel membranes. Once it’s present in the bloodstream, CO binds to hemoglobin 200 times more readily than oxygen. This forms carboxy-hemoglobin (COHb). COHb reduces the oxygen carrying capacity of the blood and impairs the release of oxygen from hemoglobin. The neurobehavioral effects include impaired coordination, tracking, and driving ability. Cognitive performance is impaired at COHb levels as low as 5%. During exposure to a fixed concentration of CO, the COHb concentration increases rapidly at the onset of exposure. This levels off after about three hours, and reaches steady state after 6 – 8 hours of exposure. Headaches, nausea and loss of consciousness occur at COHb levels of 25-40%. Permanent brain damage and death follow if COHb levels exceed 45%. Vuthisa developed a safe charcoal stove over the last few years to address this very issue.

I don’t advocate charcoal usage over wood, because of the wasteful manner in which charcoal is made and the charcoal trade destroys naturally occurring forests and contributes to global warming. There are signs that governments are trying to regulate the industry by introducing more efficient charcoal-making kilns and establishing plantations to ensure sustainability of the timber source. In Namibia, millions of hectares of encroachment bush is being converted to charcoal and sold to neighboring South Africa as barbecue charcoal. South Africa itself (according to the most recent South Africa Yearbook) is plagued with alien plant infestations, totaling more than 10 million hectares, about eight percent (8%) of the country’s land surface area. The rate of spread is alarming and their numbers are projected to double over the next 15 years. The South African government‘s Working for Water (WfW) programme, aimed at eradicating invasive alien plants and creating employment has been allocated R665,9-million ($83 million USD) in the 2010/11 year, but this amount is not sufficient to contain the problem (Source: http://www.environment.co.za/weeds-invaders-alien-vegetation/). The main culprit is Acacia mearnsii, black wattle, a hardwood that just so happens happens to make excellent charcoal. Vuthisa strongly advocates the removal (and stump treatment) of these weeds from riverbanks and open land by converting it to charcoal using a portable charcoal-making kiln similar to what is being used in Namibia. This kiln is not the most efficient of kilns (16 to 20% conversion rate), as the design should really be adapted to burn the off-gas, but it is cheap to construct and portable. This will slow the encroachment rate of the invaders and encourage micro-entrepreneurial activity to alleviate the country’s high unemployment rate.

My verdict: It seems there is no clear winner, just spare a thought for the millions of people that rely on either wood or charcoal for their day to day survival.

The Good: The use of air conditioners raises productivity and worker morale in the work place by providing a comfortable working environment and is more increasingly being used in residential areas.

The Bad: The power required to run air conditioning consumes fossil fuel, depleting reserves, and adding to global warming. Artificially changing the temperature from ambient levels confuses the body’s regulating mechanisms, designed to synchronize our bodies with seasonal variations and lowers resistance to infection – infections we are more likely to get as a result of breathing recycled air.

The effect of air conditioning on the environment does not concern this particular post, but we might be able to lessen the impact on the environment:

By supporting companies that sell systems that use safer refrigerants in order to stop ozone layer depletion; develop energy-efficient air conditioners and recover refrigerants from used air conditioners.

Switching to mini-duct; ductless or split air conditioning systems, although in some cases more expensive, are more energy-efficient, which means less greenhouse gases.

See these useful hints to increase your indoor air quality below provided by Rosalind Dall who has a personal blog dedicated to help people consume less energy and purify indoor air:

Rain and high humidity may bring moisture indoors, creating dampness, mold and mildew – big problems for healthy indoor air. Check your roof, foundation and basement or crawlspace once per year to catch leaks or moisture problems and route water away from your home’s foundation.

Help keep asthma triggers away from your house by fixing leaks and drips once they start. Standing water and moist areas encourage the growth of dust mites, fungus – some of the most common triggers that can worsen asthma. Use a dehumidifier or AC unit when needed, and clean both regularly.

High amounts of moisture in your home increase dampness and the growth of mold, which not only damage your house but threaten health. Install and run exhaust fans in bathrooms to get rid of unhealthy moisture and odors out of your home.

Ventilate your kitchen stove directly outside or open a kitchen window when you cook. Keeping emissions (including cooking odors and particles) outside of your home prevents dangerous fumes and particles from harming you or your family.

Here are some ways to save energy (and improve your home air quality):

Be sure your thermostat is located in a spot that isn’t too cold or hot. Install an automatic timer to maintain the thermostat at 68°F (20°C) during the day and 55°F (12.8°C) during the night time.

Use storm or thermal windows in colder areas. The layer of air between the windows acts as insulation and helps maintain the heat inside where you want it. Also if you haven’t already, insulate your attic and all outside walls.

Insulate floors over unheated spaces like your basement, any crawl spaces and your garage.

Close off the attic, garage, basement, spare bedrooms and storage areas. Heat just those rooms that you use, seal gaps around any pipes, wires, vents or other openings that could transfer your heat to areas that are not heated.

Vuthisa (South Africa) supports Legacy Foundation’s briquette making process.  This post aims to give the reader some background on the road that Legacy Foundation embarked upon in their quest to disseminate briquette making technologies to rural and urban poor all over the world.  To date, countless communities in 11 countries have benefited from this technology.  Despite all their efforts however the demand far exceeds the capacity of the small network of briquette practitioners to fully respond to the ever-growing problems of deforestation and poverty.

South Africa can certainly benefit from this biomass fuel briquette production system as an alternative to fuelwood use. This country has seen an incredible transition to democracy, but poverty, illiteracy and HIV/AIDS continue to dominate the lives of millions of South African households and energy security is a daily struggle here. Firewood is an essential part of life in South Africa, as it is all over the world. This precious resource plays an important role in every rural family’s life. It is here in the poorest part of the world that communities spend a good portion of their time gathering wood to cook and heat. Outside South Africa many indigenous forests are also being plundered to make charcoal. This dependence on wood has a remarkable impact on forests and economics worldwide. Globally, forests are being depleted at a rate of 2.5 to 3% per year. This happens because people need their wood for cooking, and wood today is the most available and economical resource. Destruction of these forests affects the rural poor, making it harder for them to find firewood. It also has a wider effect by contributing to global climate change.

]With wood providing the base fuel for over 2 billion people the alternatives will require massive investment beyond what the western world is willing to pay. The fact remains that unless there is a viable alternative nearly 50% of the citizens of this planet will continue to cook their one or two meals per day in a pot resting on 3 rocks and burning fuelwood. The alternative, namely fuelwood plantations, petroleum derived fuels, charcoal, solar and wind energy are proving to be impractical and expensive without subsidies from government, NGO’s or donors.

During our investigations to find an alternative to wood fuel we discovered that globally, there is a concerted effort being made to encourage a self-sustaining network of rural and urban poor to provide themselves and others in their communities with an alternative to wood fuel. These efforts are largely being spearheaded by the Legacy Foundation, USA and the fuel is biomass briquettes.

As far back as 1979 there were attempts to create artificial fuelwood briquettes using sawdust, straw or peat. These briquettes were supposed to solve the world’s fuelwood problems, but the briquette making machines were expensive, highly technical requiring ironically great amounts of electricity. It was not until the briquette process could be altered to address the real urban and rural poor environment that it would succeed. In the early 1980’s Dr. Bryant and students at the University of Washington in the USA developed a novel low-cost briquette-making process using non-woody agricultural residues, ordinary water and a hand-operated wood press. The briquette process was simple and could be established in poor and rural communities, requiring little technology and very little money. With a small effort villagers could now create their own fuelwood from agricultural residues. To make a briquette, ordinary leaves; grass and straw would be chopped and mashed into a paste. This paste would then be compressed into round cakes and dried. The resulting briquette would be sold as a fuelwood and charcoal substitute at the local market. In 1994 the Legacy Foundation picked up on Bryant’s briquette making process and extended the outreach activities. Legacy Foundation adapted the process in Malawi, East Africa, where the first pilot program was launched. The work in Africa led to other briquette extension assignments i.e Cusco, Peru, where the Legacy Foundation with the support of ADRA trained local trainers in the briquette making process leading to practical projects in three communities in the Cusco region of the Andes mountains. In Peru the same process that was used in the establishment in Africa was applied to the local skills and resources. The success of the briquette technology was not only in its simplicity, but in the fact that it offered a sustainable income, generating opportunity. Not only are briquettes easy to make, but they allow the rural and urban poor to make money in the process. By replacing firewood and charcoal with briquettes, producers can increase their income by 20%. Income generation along with saving the environment makes a sustainable solution to poverty reduction. Today, Legacy Foundation’s training and online media services have influenced the spread of the briquette technology and process beyond Malawi and Peru into eleven new countries. Other countries that have had briquette extension programs include Haiti, Uganda, Mexico, Nepal, Kenya, Mali and Tanzania.

To date, countless communities in 11 countries have benefited from this technology. Despite all their efforts however the demand far exceeds the capacity of the small network of briquette practitioners to fully respond to the ever-growing problems of deforestation and poverty. Please contact Legacy Foundation on info@legacyfound.org if you want to kick-start a 40 person training event in your area, which can reduce firewood consumption by over 900 tons per year. Training individuals in the art of briquette making is the first step in setting up a project in your area – OR – order the Legacy Foundation briquette manuals and build your own hand operated briquette press at home to transform your yard waste into fuel-briquettes. Why not build your own briquette-burning stove?  For the latest developments regarding fuel briquette-burning stoves, visit Rok Oblak’s Blog.

Anyone can make briquettes from their own leaves, grass, straw and paper. Most people accumulate sufficient newspaper to heat their homes much of the year. With briquettes, you no longer need to use wood as fuel.

If you are interested in making briquettes or training others in your area, we would recommend our training and technical manuals according to your specific needs. Fifty percent (50%) of the monies received from the sale of these manuals goes back to the Legacy Foundation, a non-profit organization, so they can continue with research and development into new briquetting technologies and for initiating briquette extension exercises.  The remaining 50% is used by Vuthisa to train local groups in the art of briquette making; to promote and develop better stoves and for the upkeep of this website. Your help in reducing global poverty while saving the environment is greatly appreciated.

For detailed information on each manual, just click on any of the images below.