Jamie Cummings Campus Box 3108 6515 Wydown Blvd St. Louis, MO [email protected] (321)412-2863 5 May 2010 Guy Genin Box 1022 One Brookings Dr. St. Louis, MO 63105 Dear Professor Genin,
I have attached a report to provide some information on my work with peanut shell charcoal in
Engineers Without Borders. The document gives some background on charcoal and research performed on charcoal made from non-wood resources, describes the research I have done with
Engineers Without Borders, and then outlines the research I plan to do during my independent study course with you next semester.
I am very excited about this work: it has great potential to positively impact many people across the globe, buy providing a wood charcoal substitute out of materials that are commonly thrown
away. Making charcoal out of peanut shells or any other waste biomass can solve problems regarding waste disposal, indoor air quality, fuel shortages, and deforestation, as well as allow the person making charcoal to turn a profit on the product and create a livelihood for him- or
herself.
I look forward to working with you next semester on this project. Sincerely,
Jamie Cummings
BIOMASS CHARCOAL:
MAKING CHARCOAL OUT OF PEANUT SHELLS IN HAITI
Jamie Cummings
Washington University in St. Louis
5 May 2010
A report on research performed on peanut shell charcoal production by students at
Washington University in St. Louis and a plan for future research to develop a finished,
economically viable, and safe process to create charcoal from waste peanut shells. This
document is meant to inform any person interested in the project, specifically those working
with Jamie Cummings on an independent study effort in the fall of 2010.
TABLE OF CONTENTS
Section 1. Executive Summary ................................................................................................ 4
Section 2. Introduction ............................................................................................................. 5
Section 3. Waste Biomass Charcoal in Haiti .......................................................................... 5
3.1 Wood Charcoal ................................................................................................................ 6
3.2 Peanut Shell Charcoal.................................................................................................... 7
3.3 Other Non-wood Charcoal Research ............................................................................. 7
3.4 Benefits of Waste Biomass Charcoal............................................................................. 8
Section 4. Previous Washington University Research........................................................... 9
4.1 Small-Scale Charcoal Production .................................................................................. 9
4.2 Charcoal Production Equipment Design and Performance ...................................... 10
4.2.1 Carbonization......................................................................................................... 10
4.2.2 Compression........................................................................................................... 12
4.2.3 Conclusions ............................................................................................................ 14
Section 5. Future Research .................................................................................................... 15
5.1 Burn Chimney............................................................................................................... 16
5.2 Binding Agent ............................................................................................................... 17
5.3 Compactor ..................................................................................................................... 18
5.3.1 Arbor Press............................................................................................................. 18
5.3.2 Hydraulic Jack Press ............................................................................................ 19
5.3.3 Illinois Institute of Technology Compactor ......................................................... 19
Section 6. Research Methods ................................................................................................. 20
6.1 Testing ........................................................................................................................... 20
6.1.1 Carbonization......................................................................................................... 20
6.1.2 Binding Agent ........................................................................................................ 21
6.1.3 Compression........................................................................................................... 21
6.1.4 Durability and Burn Quality Testing .................................................................. 22
6.2 Evaluation ..................................................................................................................... 22
6.2.1 Carbonization......................................................................................................... 23
6.2.2 Binding Agent ........................................................................................................ 23
6.2.3 Compression........................................................................................................... 23
Section 7. Expectations........................................................................................................... 23
Section 8. Works Cited ........................................................................................................... 24
Section 1. EXECUTIVE SUMMARY
Students from Washington University in St. Louis are conducting research on charcoal
made from waste biomass resources, in an effort to provide solutions to the people of Haiti,
who have long suffered from poverty, environmental degradation and unemployment.
Students are developing a method to turn waste peanut shells into charcoal that can be
used by entrepreneurial Haitians to make and sell peanut shell charcoal. Charcoal made
form waste products fills a niche in Haiti, a place where two-thirds of the population does
not have a formal job and charcoal is in high demand, so much so that 97% of Haiti’s forests
have been destroyed by the wood charcoal industry.
Charcoal is typically made out of wood. In developing countries, charcoal often made by
partially enclosing a stack of wood with green foliage and dirt, lighting the wood on fire,
then smothering the fire once it becomes full. The wood, deprived of oxygen, turns into
charcoal, which is lightweight and relatively smoke-free.
Washington University and other organizations have conducted preliminary studies on
charcoal made from non-wood biomass resources, such as sugar cane waste and paper
waste. Students at Washington University have successfully prototyped a small-scale
charcoal-making process that produces around eight three-inch diameter, one-inch thick
briquettes that burn relatively smoke-free. Students burn peanut shells in a metal
chimney, which contains and facilitates airflow through the shells, cover the shells with a
larger container to smother the fire, and then compress the resulting charcoal, called char,
into briquettes using a starch-based binding agent.
Students are now preparing for the second round of research, expanding the process to
make large batches of briquettes in a cost-effective manner. This research will include
trying larger burn chimneys for turning the peanut shells into charcoal, using sheet metal
cylinders, trash cans, and oil drums. Students will conduct formal tests to determine the
appropriate ratio of binding agent to char. Lastly, student will try several new compression
devices, utilizing levers, hydraulic car jacks, and cranks to achieve maximum compression.
This research is being conducted to determine the most cost-effective way to create charcoal
out of waste biomass. The process presents several problems, such as the difficulty to burn
such a homogenous mixture of material, the difference between wood charcoal and non-
wood charcoal and the possibility that the charcoal may not be accepted on the market.
These issues and others pertaining to the social and economic appropriateness of each piece
of equipment and each process will be addressed in the study, to create a safe, sustainable,
cost-effective method to make charcoal from peanut shells.
If successful, this process may be expanded to be used in other places with waste biomass
sources, to help people address issues of unemployment, lack of fuel, or deforestation.
Section 2. INTRODUCTION
The January 2010 earthquake in Haiti brought Haiti’s difficult circumstances to
mainstream America’s attention. Even before the disaster, Haiti was desperately poor,
with little to no infrastructure, heavy environmental degradation, and rampant
unemployment. Now, more urgently than ever, Haiti needs tools and support to create a
healthy economy and jobs that will aid in the long-term, sustainable recovery of the Haitian
people. The following research seeks to increase economic potential in Haiti by developing
a safe, economically viable method of creating charcoal out of peanut shells.
Students at Washington University in St. Louis are conducting this research to support
Meds and Food for Kids (MFK), a nonprofit organization based out of St. Louis, in the part
of their mission that includes improving Haiti’s economy by encouraging entrepreneurship
and responsible environmental practice.
MFK operates a factory in Cap Haitien, Haiti that produces a highly effective, peanut-
based malnutrition cure. Their factory produces approximately 10,000kg of product a
month, creating large amounts of peanut shells as waste. Currently, these shells are
dumped into a river. MFK would like to give these shells to individuals to turn them into
charcoal briquettes to sell.
Students at Washington Unversity in St. Louis have conducted preliminary research on
producing charcoal from peanut shells. They are now working to turn their preliminary
findings into a large-scale peanut shell charcoal-making process.
Section 3. WASTE BIOMASS CHARCOAL IN HAITI
Wood charcoal has long been a standard fuel for both the developing and industrialized
world. Although wood loses 50-75% of its energy when it is turned into charcoal, it is used
both as a fuel for factories because it is
lightweight and easy to transport and as
a fuel for household cooking in urban
areas because it is relatively smoke- and
emission-free (Sims, 2004, pp173).
Charcoal is created when plant material
is subjected to high temperatures in an
oxygen-poor environment. Instead of
combusting, the material is chemically
decomposed into charcoal as the carbon
rings of the organic material begin to
align themselves into sheets (ed.
Lehmann et. al. 2009. pp1-2). This process is called carbonization.
Besides fuel, charcoal can also be used as a soil additive. Preliminary research suggests
that powdered charcoal (also known as charcoal fines), provides the same benefits of adding
organic material to soil but is degrades much more slowly than compost or manure (ed.
Lehmann et. al. 2009. pp6). Although this option will not be tested in this research, the
option is being considered for future research into peanut shell charcoal.
3.1 Wood Charcoal
Charcoal is primarily made out of wood. Although there are many ways to create wood
charcoal, developing nations typically make charcoal using the following two methods.
In the pit method, an operator will dig a hole in the ground, ranging from one to one
hundred cubic meters. The operator starts a fire in the bottom of the hole and places dry
wood logs on top of the fire. Once the pile is fully burning, the operator covers the hole with
green foliage and earth. Depending on the amount of wood in the hole, the charcoal may
take two days to three weeks to cool down. Once cool, the charcoal is ready to use, and the
operator removes it from the hole. This completes the carbonization step. The charcoal
then may be used or sold.
Figure 1 A Haitian woman selling charcoal on the
street. One coffee can filled with charcoal costs US
$0.65
In a similar manner, in the mound method an operator will pile logs above ground and light
them on fire. Once the fire is burning thoroughly, the operator covers the pile with green
foliage and dirt (Simple Technologies. 1983. pp31-40).
3.2 Peanut Shell Charcoal
Charcoal is typically made from wood because it is very dense and is ready for packaging
and transport immediately after carbonization. Charcoal, however, can be made from any
number of organic materials, including the focus of this study, peanut shells. Using peanut
shells to make charcoal is more complex, because the user has to first compress the loose
bits of peanut shell charcoal into briquettes before he can use them, but in an area like
Haiti where wood is hard to find and environmentally detrimental to use, charcoal made
from peanut shells is a more viable option.
Like wood, the peanut shells must be carbonized. Since peanut shells are a relatively
homogenous mixture of material and do not lend themselves to ample airflow, the operator
must burn the peanut shells in a container that assists with airflow. Once the peanut
shells are burning, he or she must seal or cover the container to restrict airflow. This
process produces small, powdery pieces of charcoal, called charcoal fines or char.
To turn the char produced into functional charcoal, the operator must mix the char with a
binding agent—typically a starch boiled into a thick, gooey substance—and then compress
the mixture into briquettes (Simple Technologies. 1983. pp109-110).
3.3 Other Non-wood Charcoal Research
Non-wood charcoal production is a relatively new phenomenon in development efforts.
However, several organizations have created processes in the past 5-10 years. Washington
University students have come into contact with the work of Amy Smith at MIT and
students at Illinois Institute of Technology in Chicago.
This study was inspired by research done at MIT, lead by Amy Smith. Students at MIT
have developed a method to make charcoal out of bagasse, the waste material from sugar
cane manufacturing. They carbonize the bagasse using a 55-gallon steel drum and use
tapioca as a binding agent (Ramirez, 2005).
Washington University student have coordinated their efforts with students at Illinois
Institute of Technology, who have developed a machine to extrude logs of biomass charcoal
using a threaded rod and crank. The machine is designed to achieve maximum
compression to mimic the density of wood charcoal, with the goal of making the charcoal
competitive on the market.
3.4 Benefits of Waste Biomass Charcoal
Haiti has attracted attention from students at Washington University and others doing
research on charcoal because it has such great potential for charcoal made from materials
other than wood.
Charcoal is a staple in the Haitian lifestyle. As the cooking fuel of choice for most Haitians,
charcoal made from wood is both highly sought after and becoming more and more difficult
to find. Haiti is 97% deforested, meaning that only about three percent of the trees that
once existed on the island now stand. Such mass deforestation has devastated the Haitian
countryside, resulting in major landslides that have stripped the land of topsoil essential
for productive farming, damaged homes, and killed the reefs around the island that once
supported a vibrant fishing industry.
In addition, Haiti suffers from a lack of infrastructure and unemployment—around two-
thirds of its people do not have formal jobs,but live on subsistence farming alone (Haiti.
2009). Such a state of affairs makes rebuilding from the recent earthquake and overcoming
the poverty that has gripped the country for decades extremely difficult. As a result, many
entrepreneurial Haitians have created their own small businesses, selling goods, repairing
equipment, and doing a multitude of other tasks. Such efforts build the Haitian economy
despite the lack of infrastructure, and aid to both improve the lives of the business owners
and improve the state of the economy to allow others to do the same.
Charcoal made out of waste biomass, then presents a way to combat both of these problems:
unemployment, by providing extra job opportunities for people with access to excess
biomass, and environmental degradation, by decreasing the demand for wood charcoal.
Haiti, however, is not the only country with potential for waste biomass charcoal. Waste
biomass is available in many developing communities, and if there is a need for extra fuel,
or a replacement for wood charcoal, a community could benefit from producing charcoal
from sources other than wood instead. If this process is proved to be feasible, other
organizations and individuals should be able to use this method to create waste biomass
charcoal of their own.
Section 4. PREVIOUS WASHINGTON UNIVERSITY RESEARCH
Students from Washington University in St. Louis’s chapter of Engineers Without Borders
have been working with Meds and Food for Kids (MFK), a non-profit organization based out
of St. Louis, to create charcoal out of waste peanut shells from the factory they operate in
Cap Haitien, Haiti. MFK’s factory produces a highly effective peanut-based malnutrition
treatment. Beyond treating children with malnutrition, the factory works to improve the
Haitian economy by employing Haitian workers and buying local peanuts, working with
farmers to improve crop yields and promote sustainable farming practices, and encouraging
entrepreneurship in the community.
Initially, MFK would like to help one or two Haitians to start up their own business making
and selling charcoal. If successful, MFK, as well as other organizations working in
developing areas, can spread this technique to other entrepreneurial individuals.
4.1 Small-Scale Charcoal Production
Washington University students have developed a small-scale method to create charcoal
out of peanut shells modeled after the method created at MIT.
First, peanut shells are loaded into a metal container with holes in the bottom for
ventilation, like a Weber charcoal chimney with the handle removed. The students place
newspaper in the bottom and light the shells on fire. Once the shells are thoroughly lit and
the smoke from the fire turns clear, the students cover the fire with a plastic five gallon
bucket and seal the bottom with dirt. The shells then carbonize in the anaerobic
environment, leaving only charcoal fines. When cool (for this small-scale batch, it takes 30-
45 minutes), the fines are ready to be turned into briquettes. Students crush the fines into
powder and mix them with a starch-based binder (cooked tapioca flour). They then
compress the mixture into a briquette, approximately three inches in diameter and one inch
thick, using a PVC pipe as a mold and a smaller PVC pipe as a plunger to compress the
briquettes. After one to two days of drying, the briquettes are ready to be used or sold.
4.2 Charcoal Production Equipment Design and Performance
Peanut shell charcoal production requires two pieces of equipment: one piece to carbonize
the peanut shells, and once piece to compress the charcoal fines into briquettes. To date,
Washington University students have produced charcoal on a small-scale only, producing
five to ten briquettes with each trial. They have used two pieces of equipment to carbonize
peanuts and two to compress briquettes.
4.2.1 Carbonization
Students tried two different pieces of equipment to carbonize the peanut shells. Unlike
wood, which is conducive to burning because when you stack logs of wood, the space in
between logs distributes air and heat from one part of the fire the rest, peanut shells do not
lend themselves to even air distribution. To solve this problem, students used metal
containers with holes to facilitate the airflow needed and as well as to separate the shells
and the resulting char from the surrounding dirt.
Coffee Cans
The first container students tried was a gallon-size coffee
can with holes punched in it. Students placed a layer of
crumpled newspaper in the bottom of the coffee can, placed
a small amount of peanut shells (2-3 handfuls) on top of the
newspaper, and lit the newspaper on fire. They slowly
added peanut shells to the can, taking care not to smother
the fire, until the can was 2/3 full. After the shells were
fully ignited and producing clear smoke, students covered
the coffee can with a larger metal can or a large glass jar.
The amount and configuration of holes (see figures) affected the ease with which students
could light the peanut shells. Regardless of hole
configuration, the peanut shells were very difficult to keep
lit. It took on average eight to fifteen minutes to light each
batch and out of the ten batches students made using coffee
cans, at least four had to be restarted because the peanut
shells had smothered their own fire.
Figure 2 A coffee can with holes
punched up the side. Students tried
several different hole configurations,
but this one, with holes all the way up
the sides, proved the best.
Charcoal Chimney
Students tried a second carbonization method using a charcoal chimney. A charcoal
chimney is a metal cylinder used to light finished charcoal briquettes on fire. Students
filled the chimney two-thirds full of peanut shells, placed crumpled sheets of newspaper in
the compartment underneath the chimney, and lit the newspaper on fire. Once the peanut
shells were lit fully, students covered the chimney with a five-gallon plastic bucket.
This device, although intended for finished charcoal briquettes, is designed to facilitate
airflow, and proved to be an excellent means to light peanut shells. Unlike the coffee cans
which required the user to slowly add shells to ensure that the fire did not go out, students
did not have to do anything beyond loading the chimney with all of the shells at once, and
lighting the newspaper on fire.
Since the chimney lights the shells more quickly, the shells should be more evenly lit. This
should causeless shells to be consumed as ash while the other shells catch fire.
Figure XXa: A Weber charcoal chimney
loaded with charcoal. This is instead loaded
with peanut shells to function as a burn
basket.
Figure XXb: Charcoal chimney with a foil
pan placed in the bottom
4.2.2 Compression
After carbonizing the peanut shell, students must mix the char with a binding agent and
compress the mixture into briquettes. Students mixed 1/8 cup of cooked tapioca flour with
with 1 cup of powdered char then compressed the mixture using the two following methods.
Peanut Butter Jar Lids
Students first made briquettes using plastic lids from peanut butter jars (roughly 2.5” in
diameter and ½” thick). Students placed a plastic bag inside of the lid (to keep the
briquette from sticking to the inside of the lid), placed roughly one cup of char mixture into
the lid, folded the plastic bag over the top of the char mixture and pressed the mixture into
the lid using the top of a smaller glass jar. Typically, they compressed the briquettes with
their hands or by standing on the mold and jar. Students then removed the mixture and
plastic bag from the lid, peeled the plastic bag away from the briquette, and set the
briquettes out to dry.
This technique was fairly easy to perform and produced evenly sized briquettes that burned
well. However, the briquettes were not very thick. Students showed the briquettes to
people in Haiti, who disapproved, saying they looked too fragile.
PVC Plunger
Students tried a second method using two PVC pipes in a plunger-like assembly. One 3-
inch diameter, 2-foot long PVC pipe functioned as the mold for the briquettes. Students
rested the PVC pipe on the ground, with one open end facing the ground. They then filled
the mold with alternating layers of plastic spacers cut from milk jugs and char mixture.
After loading, they inserted a longer 2” diameter pipe into the first pipe and tapped on the
end of the 2-in pipe with a hammer to compress the briquettes. Then the students pulled
up on the 3” diameter pipe, removed the stack of briquettes, separated them, and set them
out to dry.
The PVC plunger produced more uniform, denser briquettes. Using a hammer to compress
the briquettes provides greater compaction potential than simply pressing with one’s hands
or feet. In addition, using a PVC plunger assembly allowed the students greater flexibility
regarding the size of the briquette, because there are many sizes of PVC, whereas various
size lids that work as molds are harder to find.
Still, a PVC plunger is not ideal because it allows the user to compress only one or two
briquettes at a time. The impact of a hammer still is not powerful enough to compress a
large stack of briquettes at once.
4.2.3 Conclusions
From these tests, students determined the importance of airflow while lighting the peanut
shells on fire. A burn chimney with appropriate ventilation will allow the shells to light
quickly and uniformly. For small-scale applications, using a charcoal chimney is an
effective way to carbonize peanut shells. One batch uses approximately 1 square foot of
peanut shells and creates eight briquettes. Larger scale applications will need to focus on
ample ventilation and ensure that the chimney is made with materials available in the
area.
For small-scale applications, a PVC plunger assembly allows a user to create exactly-sized,
uniformly compressed briquettes. However, this process is time-intensive. A person
making large numbers of briquettes in a day needs a press with higher capacity and
multiple molds.
Section 5. FUTURE RESEARCH
In 2010, Students at Washington University will expand their previous research to develop
a large-scale charcoal-making process that can be used by one or two Haitians. This
process must be economically viable, environmentally responsible, and safe for the
operators. Students will work with people in Haiti to determine the available construction
materials for equipment, develop methods appropriate to the culture and skill level of the
person making the charcoal, and determine whether this process will be cost-effective in
this situation. The findings of this research will be documented and distributed to aid
organizations and through online appropriate technology websites. Students aim to have a
finalized process by the end of 2010.
5.1 Burn Chimney
The home charcoal chimney,
described in Section 4.2.1, proved
highly effective at lighting a small
amount of peanut shells. Students
will construct larger chimneys made
out of sheet aluminum modeled after
this design. The chimneys will have
twice the height and diameter and
eight times the volume. Instead of
producing around eight briquettes
per batch, these chimneys should
create enough char for 60-70 briquettes per batch.
Larger capacity metal containers, such as oil drums and metal trash cans require less
machining because they are already cylindrical. Such items, especially oil drums, are
available in places such as Haiti.
Both containers would have the top removed and small holes punched into the bottom and
sides modeled after the hole configuration in the home charcoal chimney.
Figure 5 An oil drum altered to function
as a burn chimney. Figure 5 A trash can altered to function as a burn
chimney.
Figure 3 Burn chimney twice the size and eight times the
volume of the home charcoal chimney used in the initials
trials. This chimney will be made out of sheet aluminum.
Oil drums and trash cans create concerns regarding the emissions they produce when
peanut shells burn inside of them. Oil drums often store hazardous chemicals before they
are discarded, and most are painted. In addition, metal trash cans are often made of
galvanized metal, which releases toxic zinc gases when burned.
For the safety of the students, they will make sure they buy food grade or refurbished oil
drums in the study. Students will light the initial fire in the galvanized trash can very
carefully and clear the area during the first burn.
Although the students will take the necessary precautions, people using this method in
developing countries may not be educated about the dangers of burning chemicals, or may
not value their own safety enough to take these precautions. The evaluation process will
take this safety concern into account.
5.2 Binding Agent
Students seek to find the most appropriate binding agent to mix with the charcoal powder
make briquettes. The binding agent is made from a starch cooked with hot water. Students
used flour made from cassava (also known as tapioca), a common vegetable in Haiti. To
make the binding agent, students mix one part flour to one part water, then mix that paste
with four parts of boiling water. They cook the mixture until it turns clear and has a thick
consistency.
Using the right amount of binding agent is important in the charcoal-making process. If
the producer uses too much binding agent, they will spend extra money on tapioca flour, the
only recurring cost to make charcoal if the peanut shells are free, and the briquettes will
produce more smoke, because the binding agent has not been carbonized and therefore
produces smoke when burned. If the briquette is too smoky or too expensive, it won’t be
able to compete with wood charcoal on the market. On the other hand, using too little
binding agent will make the briquettes less durable and more likely to fall apart during
transport and cooking.
In informal trials using peanut butter jar lids as molds, students found that roughly 1/8 cup
of the binding agent per 1 cup uncompressed char powder was the ideal proportion for an
adequately bound briquette. To further this initial research, students will conduct trials
using different char-to-binding agent proportions.
When the students visited a Kingsford charcoal factory in Missouri, they discussed adding
Borax to the binding agent. According to the managers we talked with at Kingsford, adding
borax makes the starch more effective and requires less starch overall. Students will test
borax in their research and conduct trials using borax as well.
5.3 Compactor
The last component of the peanut-shell charcoal making process is compression. Students
aim to create a compactor that will compress the briquettes as much as possible, to make
very dense briquettes thatmimic wood, and to bind the char more thoroughly to reduce the
amount of binding agent each briquette needs.
The two presses described in this section utilize the PVC plunger compression method used
for our small-scale trials, described in Section 4.2.2 Compression.
5.3.1 Arbor Press
The arbor press utilizes a simple lever arm to push down a plunger into a PVC plunger
assembly. The prototype press could be made out of 2x4 lumber, rebar, or PVC filled with
concrete. Since 2x4 lumber is cheap and easy to work with, students will make the first
prototype out of wood. Subsequent versions may be made of out more appropriate
materials for use in Haiti.
The press, two feet long and 14 inches high, is comprised of a base which supports and
stabilizes the PVC mold and plunger, a lever arm to increase force to the plunger, and
vertical pieces that connect the base and the lever arm.
Figure 6 The side view of an arbor press. A person pushing on the lever
arm with 100lbs of force will put 200lbs of force on the briquettes, or 28
psi.
5.3.2 Hydraulic Jack Press
For much higher pressure on the briquettes, a hydraulic jack may be the ideal solution.
Hydraulic jacks, meant to lift cars for repairs, are available in Haiti and moderately priced.
A jack can provide ample compression for briquettes. Students at MIT have used this type
of press to make briquettes in Haiti, using a frame made of out 2x4 lumber.
Students will construct a prototype press using 2x4 lumber. The press will be 4 feet tall
and two feet wide with one hydraulic jack oriented to press a 2x4 beam down to compress
three PVC plunger assemblies. If a 6-ton jack were to operate at full capacity, it would
provide over 550psi to the briquettes. This should be enough force to compress multiple
briquettes in a stack.
(also insert sketch)
5.3.3 Illinois Institute of Technology Compactor
Students at Illinois Institute of Technology are developing the final briquette compression
model in this study. The compactor extrudes logs of charcoal using a threaded rod and
crank that pushes char mixture through a series of PVC pipe reducers. The machine
produces 1 ¼ inch diameter logs of char, comparable to the wood char sold in Haiti.
Since IIT is only developing the compactor and not the char-making process, they have not
been able to test their compactor with actual char. Students at Washington University will
test IIT’s charcoal compactor using char from their experiments.
Section 6. RESEARCH METHODS
To create a large scale peanut charcoal operation, students will prototype three burn
chimneys and two briquette compactors and will optimize the amount of binding agent to
use. The trials will use peanut shells from floor sweepings from Texas Roadhouse Grill.
After the trials, students will evaluate the feasibility of each process and identify
improvements, while considering the economic and social constraints on the process.
6.1 Testing
Students will test the three major components of the process, carbonization, the binding
agent, and compression, individually to determine the most effective variations of each
process, and whether any variations are satisfactory for the final process. Each trial will
produce ten briquettes to compare: eight to burn and two to test durability.
6.1.1 Carbonization
Students will test three pieces of carbonization equipment:
a chimney made of sheet metal,
a trash can, and
an oil drum.
They will make two batches of char in each burn chimney. Students will place the same
weight of peanut shells in each chimney from the same well-mixed bag of shells to ensure
equitable input quality. They will cover each chimney with a 50 gallon metal trash can.
Before covering the basket, students will record:
the temperature of the top layer of peanut shells once every minute,
the time it takes for the peanut shells to reach 280C (the temperature at which
carbonization begins), and
the time it takes for the smoke to turn mostly yellow and mostly clear.
After covering the chimney, students will record the temperature of the top of the cover
once every five minutes.
After the assembly is cool, students will weigh the char from each burn chimney,
qualitatively assess the thoroughness of the carbonization, and conduct density testing on a
portion of the char using a proctor compaction test.
The sudents will create 10 briquettes from the char from each burn chimney for durability
and burn quality testing, described below.
6.1.2 Binding Agent
Students will test the proportion of binding agent by running ten trials of ten briquettes
each. This trial will use the sheet metal burn basket for carbonization and the hydraulic
jack press for compression. The first five trials will use five different proportions of binding
agent to char and trials 6-10 will use the same amounts of binding agent per one cup
uncompressed char, but with ½ tsp borax added to each.
Table 1a. Binding Agent Trials 1-5 Table 1b. Binding Agent Trials 6-10
Trial
Number
Amount of binding
agent per one cup
uncompressed char
Trial
Number
Amount of binding
agent per one cup
uncompressed char
Amount of Borax
per one cup
uncompressed char
1 1 Tbsp 6 1 Tbsp 0.5 tsp
2 1.5 Tbsp 7 1.5 Tbsp 0.5 tsp
3 2 Tbsp 8 2 Tbsp 0.5 tsp
4 2.5 Tbsp 9 2.5 Tbsp 0.5 tsp
5 3 Tbsp 10 3 Tbsp 0.5 tsp
Students will qualitatively evaluate the briquettes after compression and after drying,
noting excessive or inadequate moisture, fragile-looking briquettes, etc.
Students will also evaluate the durability and burn quality of the finished briquettes
according to the testing procedures described below.
6.1.3 Compression
Students will test the three compactors by creating 10 briquettes using each compactor.
For this test, they will use char created in the sheet metal burn chimneys with the
previously optimized ratio of 1/8 cup tapioca binding agent to 1 cup char, with 1 ½ cups of
char mixture forming each briquette.
The same student will use each machine, while two others observe the process and collect
data. The student performing the process will “talk aloud” all of his or her thoughts about
the process as he or she works.
The observing students will measure the time it takes to:
load the device,
compress the briquettes, and
remove the briquettes from the machine.
Students will qualitatively evaluate the machine’s ease of use by writing notes about any
difficulties or physical strains the machine causes.
Once the briquettes have been made and dried, students will measure final dimensions,
density, and perform durability and burn quality testing.
6.1.4 Durability and Burn Quality Testing
Students will subject all of the finished briquettes created in the tests described in the
previous three sections to the following testing.
First, students will burn eight of the briquettes, timing the amount of time it takes for the
fire to reach 500oF, and how long it takes for the fire to cool down to 500oF after burning.
Students will also record qualitatively the amount of smoke produced by the charcoal.
In order to ensure the briquettes are lit as equitably as possible, students will use an
electric fire starter to light each batch of briquettes.
Students will use the remaining two briquettes from each batch for durability testing. The
briquettes will be dropped from 5 foot heights until a substantial piece (more than one
centimeter wide) breaks off. Students will record the number of drops it takes to break the
briquettes.
6.2 Evaluation
Students will use the data collected in the previous four sections to determine the
feasibility of each device/technique tested. After the tests and data analysis is complete,
students will determine which processes need to be improved and design new equipment or
techniques to address the issues raised.
6.2.1 Carbonization
The two most pertinent pieces of data for the carbonization test are (1) the amount of char
produced per batch and per pound of peanut shells, and (2) the smoke content of the
finished, burning charcoal. If a piece of equipment yields significantly less char or produces
too much smoke, students will need to change the design or discard it altogether.
6.2.2 Binding Agent
The important data for the binding agent test is the durability of the briquette and the
amount of smoke produced by the briquette. If the briquettes are too fragile or too smoky,
they will not be readily accepted on the market.
6.2.3 Compression
The compression testing will mostly rely on charcoal density and durability data. If the
charcoal is significantly less dense than wood charcoal or prone to breakage, once again, it
will not be accepted on the market as a competitor to wood charcoal.
Section 7. EXPECTATIONS
This research is a vital step in developing a safe, effective charcoal-making process for use
in developing countries. If successful, such a method can be used across Haiti and the globe
to allow entrepreneurs with access to waste biomass a means to provide fuel and income to
their families. In addition, in areas threatened by deforestation, the extra charcoal
provides a more sustainable fuel supply than simply cutting down trees and turning them
into charcoal, while still providing the same fuel that is widely used in many developing
nations. Such opportunity provides for long-term, sustainable development, that teaches
the proverbial man to fish, instead of just giving one away.
Section 8. WORKS CITED
Ramírez, Andrés. A comparative analysis of emissions from bagasse charcoal and wood
charcoal. May 2005. Cambridge:Massachusetts Institute of Technology
<http://hdl.handle.net/1721.1/32941>.
Haiti. The World Factbook 2009. Washington, DC: Central Intelligence Agency, 2009.
ed. Lehmann, Johannes, Stephen Joseph. Biochar for Environmental Management.
Virginia: Earthscan. 2009.
Mechanical Wood Products Branch. Forest Industries Department. Forestry Department.
Simple Technologies for Charcoal Making.” Rome:Food and Agriculture
Organization of the United Nations. 1983.
Ramírez, Andrés. A comparative analysis of emissions from bagasse charcoal and wood
charcoal. May 2005. Cambridge:Massachusetts Institute of Technology
<http://hdl.handle.net/1721.1/32941>.
Sims, Ralph E.H. Bioenergy Options for a Cleaner Environment. Elsevier Ltd. 2004: United
Kingdom.