DESIGN AND MANUFACTURING OF A BIOMASS CARBONIZING FURNACE.pdf
1. MBEYA UNIVERSITY OF SCIENCE AND TECHNOLOGY
COLLEGE OF ENGINEERING AND TECHNOLOGY
DEPARTMENT OF MECHANICAL AND INDUSTRIAL ENGINEERING
MODULE NAME: MECHANICAL PROJECT I
MODULE CODE : 6307
PROJECT TITTLE: DESIGNING AND MANUFACTURING OF THE BIOMASS CARBONIZING
FURNACE.
2. PARTICIPANTS
NAME REGISTRATION NUMBER CA NUMBER
EMMANUEL CHACHA MATUTU 20100123010111 CA/DME/22/2819
ABDULAH Z. MNYAWAMI 20100123010008
SAMWEL H. NAMGAMBWA 20100123010061 CA/DME/22/2824
4. Introduction
A biomass carbonizing furnace is an equipment used to process biomass briquettes,
woods and forestry residues into charcoal. The biomass briquettes are made from
sawdust and other agricultural residues such as crop straws, rice husks, bamboo
shavings and grasses by means of a briquetting machine. Within the furnace the
biomass briquettes undergo a process known as carbonization process.
Carbonization is a process whereby waste biomass such as plants and dead animals
remains are re-invented into carbon in a manner it emerges as an energy rich
charcoal. The process vividly redefines the principle of renewable energy and
power generation as well environmental conservation.
Carbonized briquettes are made from biomass that has undergone pyrolysis
process in which the biomass is heated in an inert atmosphere to high
temperatures, about 550 degrees of Celsius until absorbed volatile organic
compounds are expelled thus increasing calorific value and energy content.
(Mahmoud & Ahmed, Biomass Carbonization).
5. Problem Statement
Over the years, due to depletion and rising cost of the fossil fuels along with
an increment in the greenhouse effect facilitating global warming triggered
energy and environment concerns which are supposed to be dealt with
before they become severe or even fatal. This urged the researchers and
experts within various concerned fields to find the alternative for fossil fuels
thus an increased interest in renewable and biofuel energy sources which are
less costly and environmental friendly, whereby these alternatives can be
produced from biomass exemplarily, the biomass briquettes which have
been implemented few years ago but still imposing some significant
challenges especially poor calorific value due to massive moisture content
present in the briquettes which has proved the briquettes to be in-efficient
and environmental un-friendly as they tend to produce a significant amount
of smoke and ashes.
7. Expected Solution
To eliminate the challenge, it is vital to design and manufacture a
biomass carbonizing furnace for small scale production that will
facilitate carbonization of the biomass briquettes so as to reduce
moisture content of the briquettes to enhance their calorific value and
discourage smoke and ash production.
8. Objectives
Main objective
• The main objective of this project is to design and manufacture a biomass carbonizing
furnace.
Specific objectives
i. To study the properties of biomass as fuel
ii. To study the relative methods used for biomass carbonization
iii. To determine the constructional features of the carbonizing furnace
iv. To select the convenient materials for the carbonizing furnace
v. To design the carbonizing furnace (furnace, reactor, barrel, lid and chimney)
vi. To select standard parts(burner, insulators, tubes)
vii. To manufacture the designed carbonizing furnace
viii. To test the manufactured carbonizing furnace
9. Significance of the Project
The manufactured carbonizing furnace is expected to discourage the
challenges concerning with the present small scale biomass briquettes
production, these include reducing the briquettes moisture content
and enhancing the calorific value of the briquettes so that they can
burn longer with minimal production of ash and smoke.
10. Scope of the Project
The biomass carbonizing furnace manufactured is for small scale
biomass production and not for medium and large scale production.
Also, the manufactured biomass carbonizing furnace will be made
available for technical studies on how to fabricate more furnaces which
can be used for medium and large-scale briquette production around
the region.
11. Methodology
The project methodology is concerned with procedures or plan of
action to conduct the project in accordance with the specific
objectives. These are tabulated as follows:
12. Methodology
Specific objectives methodology Output
i. To study the properties of
biomass as fuel
ii. To study relative methods used
for biomass carbonization
iii. To determine the
constructional features of the
biomass carbonizer
• Literature review • Characteristics of biomass as
fuel
• Biomass carbonization methods
• Constructional features of the
biomass carbonizer
iv. To select the materials for
biomass carbonizer construction
• Engineering materials selection • Engineering materials for the
biomass carbonizer construction
v. To select the standard parts • Machine standard parts
selection
• Standard parts of the carbonizer
v. To design the carbonizing
furnace
• Designing • Engineering drawings (detail
and assembly drawings)
vi. To manufacture the designed
furnace
• Manufacturing • Manufacturing process
viii. To test the manufactured
furnace
• Testing • Testing procedures
• Performance parameters
• Operational parameters
13. Literature review
A general overview of the project topic is elaborated by the literature review. It also
gives information about various existing biomass carbonizing methods and
carbonizing furnaces that are currently in use. All information is obtained in
different books, notes, and internet browser.
An overview of biomass crops
Biomass is plant-based material used as a fuel for heat or electricity production. It
can be in the form of wood, wood residues, energy crops, agricultural residues, and
waste from industry, farms, and households(Wikipedia, the free encyclopedia).
According to Bassam (2010) and McKendy (2001), biomass is defined as the recent
organic matter which originates from the photosynthetic conversion process in
plants. It can be derived from a number of sources and ultimately used for several
purposes. Sources of biomass can be classified into four main categories namely,
woody plants (forestry wastes), herbaceous grasses (Miscanthus, Arundo Donax),
aquatic plants (algae) and manures (Bush,2015).
14. Literature review
Biomass crops have always been used as a major source of energy for a wide range
of purposes ranging from use as chemical feedstock to production of electrical or
heat energy (McKendry, 2001). For each function for which the crop is to be used,
the properties differ. However, ideal energy crops are those which have more or
less the following general characteristics, according to McKendry, 2001:
• High yield of biomass
• A composition with low percentage of contaminants
• Low energy input, hence low cost of production
• Low requirements in terms of additional nutrients
Therefore, when choosing a crop for use for bioenergy production, it is important
to carry out tests to determine the extent to which the crop meets the
characteristics above and can thus, be considered suitable for its purpose. In line
with this, it is important to clearly figure out the bioconversion technique that is to
be used, the final product desired and the application.
15. Literature review
Biomass classification
According to (Vassilev et al., 2012), biomass can be classified as follows
according to their existence in nature and composition:
• Wood and woody biomass
• Herbaceous biomass
• Animal and human waste biomass
• Biomass mixture
16. Literature review
• Wood and woody biomass
The woody biomass includes different components, mainly consisting of
carbohydrates and lignin. Generally, this category consists of materials such as
trees and roots residues, bark and leaves of woody shrubs both above and
below ground, which can be converted into energy by direct combustion (or
gasification) or through numerous conversion processes (Vassilev et al., 2012).
17. Literature review
• Herbaceous biomass
Herbaceous biomass is from plants that have a nonwoody stem and which die
back at the end of the growing season. This biomass includes most agricultural
crops and grasses, including bamboo and wheat straw(EN ISO 17225-1:2014;
Alakangas et al., 2016).
18. Literature review
• Biomass mixture
In some cases, when several substrates belonging to different classes,
mentioned above, are in mixed form, they are referred to as biomass
mixture.
19. Literature review
• Animal and human waste biomass
The most common sources are bones, meat meal, various types of animal
manures, and human dung (Vassilev et al., 2012). In the past, these
wastes were recovered and sold as fertilizers or simply used on agricultural
land, but the introduction of more stringent environmental regulations on
pollution, health, and odor concerns, has led to proper waste management.
Anaerobic digestion is the most convenient method to convert this waste into
useful products. For instance, biogas, as a bioenergy product of the process,
could be used to generate electricity in turbines and internal combustion
engines or could be burned directly for cooking or to heat rooms and water
(Horan, 2018).
20. Literature review
Biofuels, these are fuels derived from biomass(that is plants or algae
materials or animal waste). Some long exploited biofuels include Wood,
Grass, Ethanol, Biodiesel, Methane and Biogas.
Since such feedstock material can be replenished readily, biofuel is
considered to be a source of renewable energy, unlike fossil fuels such
as petroleum, coal, and natural gas. Biofuel is commonly advocated as
a cost-effective and environmentally benign alternative to petroleum
and other fossil fuels, particularly within the context of rising
petroleum prices and increased concern over the contributions made
by fossil fuels to global warming (Patricia A. Woertz, 2015).
21. Literature review
Bio-energy, is the energy produced by the biofuels. According to (David
Hodgson et al,. 2022), bioenergy is a source of energy from the organic
materials that make up plants, biomass. Biomass contains carbon absorbed
by plants during photosynthesis and when this biomass is used to produce
energy the carbon is released during combustion and simply returns to the
atmosphere, making the modern bioenergy a promising near zero emission
fuel. The merits influencing the promotion of bioenergy include the following
• Supply domestic clean energy sources
• Reduce the rate of emission
• Offer employment opportunities to community members
• Assist revitalization of the rural economy
22. Literature review
Biomass, through treatment and conversion processes, can be
converted into different types of energy carriers. The parameters that
determine the choice of the production process are diverse but the
most important ones include the renewable end-product required, the
quality and quantity of biomass, and the cost of the process (Dalena et
al., 2017). Biomass can be converted into two main types of energy
carriers (McKendry, 2002):
• Electrical/heat energy and
• Transportation fuels
23. Literature review
Biomass conversion
The processes involved in biomass conversion into energy are
commonly classified as follows:
• Thermochemical conversion
• Biochemical conversion and
• Physico-chemical conversion
24. Literature review
1. Thermochemical conversion processes
In thermochemical conversion process, heat and chemical processes are induced
on the biomasses in order to produce energy. There are four thermochemical
processes, namely:
• Combustion: biomass is burnt under the presence of oxygen to produce energy.
• Liquefaction: is a biomass conversion process conducted in water at
moderate temperatures ranging between and high pressures to attain a
liquid bio-granulate, similar to crude oil.
• Gasification: The gasification process converts solid biomass into a gas,
called gas or syngas, mainly composed of CO, H2 and N2.
• Pyrolysis: Pyrolysis converts biomass at temperatures around 500 ◦C in
absence of oxygen to liquid (bio-oil), gaseous and solid (char) fractions.
25. Literature review
Pyrolysis
Pyrolysis is the conversion process of specific biomass into liquid (bio-oil),
solid (charcoal), and gaseous (combustible gas) products through partial
combustion at temperatures around 500 °C and in the absence of oxygen
(Lebaka, 2013). High temperatures allow the vaporization of the volatile
components of the biomass producing gases, whose vapours are condensed
into liquids by liquefaction. The liquid fuel resulting from this process can be
stored and subsequently used for various heating and electricity generation
applications. In addition to liquid fuels, the pyrolysis process also produces
other combustible products such as charcoal, gas, and many other value
added chemicals (Kaushika et al., 2016).
27. Literature review
According to (Kaltschmitt, 2013) Pyrolysis can be conducted in the following ways:
• Carbonization, the most ancient and known pyrolysis process, occurring at temperatures
between 300 and 500 °C. From this process, only a solid fraction (vegetable coal) is recovered.
• Slow or conventional pyrolysis occurs at moderate temperatures around 500 °C, through which
approximately three fractions are obtained in equal proportions. Slow pyrolysis requires longer
reaction and transformation times than fast pyrolysis due to low temperature and heating values.
• Fast pyrolysis takes place at medium-low temperatures (from 500 to 650 °C), in which the
gasification reactions take place quickly and with short contact times, so that the intermediate
compounds are reformed, bringing the production of the liquid fraction up to 70-80 wt.% of the
incoming biomass. Generally, this type of pyrolysis produces 60% of bio-oil, 20% of bio-coal, and
20% of gas.
• Flash pyrolysis is performed at temperatures higher than 650 °C with contact times of less than
one second and favors the production of the gaseous fraction (efficiency reaching 80%).
28. Literature review
Biomass carbonization
Carbonization is a pyrolytically process that typically heats biomass feedstock
in a kiln or retort or furnace at temperatures around 400 °C (generally
between 300 and 900°C) in the absence of air. The process is carried out in
order to convert the biomass into a highly carbonaceous charcoal-like
material (sciencedirect.com).
The carbonization process occurs slowly heating the biomass to high
temperatures exceeding 400°C and for several hours. The products from this
process are charcoal when it is used as fuel, biochar when used as fertilizer
or soil amendments, biocoke for metal extraction, and finally activated
carbon when regular charcoal is upgraded for adsorption and purification
purposes.
30. Literature review
The merits of the carbonized products include the following:
• Renewable solid fuel source
• Carbon-negative process
• Reduces dependability on carbon positive fossil fuels
• Improves the fertility of the soil and subsequently the crop production yield
• Less chemical fertilizers required
• Soil remediation
• Improves water quality
• Counteracts land desertification by increasing its fertility
• Improves water and nutrition retention in the soil
31. Literature review
Carbonization reactors
There exist hundreds of simple and complicated carbonization reactors
with different technologies such as kilns, retorts, and converters. Kiln
describes the simplest traditional char-making equipment from
wooden logs. Retorts and converters are the industrial reactors that
can produce char as well as capture some volatiles and bio-oil. The
difference between retorts and converters is the size of the biomass
used. Retorts are used for long and thick wood logs, while converters
are used with small particles of biomass(Garcia Nunez et al., 2017).
32. Literature review
According to (Boateng A.A. et al., 2015), these reactors can be classified as follows:
• The required final product
• Mode of operation (batch or continuous)
• Heat transfer method (direct, indirect, or microwave)
• Input heat source (electric, gas, or biomass combustion)
• Biomass loading method
• Operating pressure
• Construction material (soil, brick, concrete, or steel)
• Mobility (stationary, portable)
33. Literature review
According to (Mahmoud A. and Ahmed E., 2020), biomass
carbonization method can be classified as:
• Batch carbonization and
• Continuous carbonization
34. Literature review
Main parts of the biomass carbonizing reactor system include:
• A furnace: for providing heat to the biomass
• A reactor: for containing and controlling the energy released by
controlling the chemical reactions during carbonization.
• A chimney: for isolating the carbonization exhaust gas from the
environment.
• A barrel: for holding the biomass feedstock during carbonization.
• A lid: used to cover the reactor system to increase thermal efficiency
of the furnace.
