As be a collective of them all. Following is

               As we have
already mentioned, bio-oil is a mixture of various compounds, its properties
have proved to be a collective of them all. Following is a detailed account of
the physical properties and other characteristics of the crude bio-oil that has
been derived from the wood.

2.4.1.1 Appearance

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Pyrolysis oil is a dark brown free flowing liquid. Depending upon the
initial feedstock and the mode of fast pyrolysis, the color can be almost black
through dark reddish brown to dark green, being influenced by the presence of
micro-carbon in the liquid and by the chemical composition. Hot vapors
filtration gives a more translucent reddish brown appearance due to the absence
of char. High nitrogen contents in the liquid can give it a dark green tinge.

2.4.1.2 Odor

                   The
liquid has a distinctive odor, an acrid smoky smell, which can irritate the
eyes if exposed for a prolonged period to the liquids. The cause of this smell
is due to molecular weight aldehydes and acids. The liquid contains several
hundred different chemicals in widely varying proportions, ranging from
formaldehyde and acetic acid to complex high molecular weight phenols, a hydro
sugars and other oligosaccharides.

2.4.1.3 Solids

                   The solids
refer to the char produced during the process of pyrolysis. Their typical
amount retained in the liquid oil is 0.2% by weight. However, 0.1 weight % is a
good level and 1% is often consumed.

2.4.1.4 Ash

                  There is
practically no ash to be separately identified from the char. All of it is
associated with the char and is assumed to be 0%.

2.4.1.5 Moisture Content

                   An
average value is 25% by weight, but the values can range from 15 to 35%. The
water in the bio-oil comes from the moisture in feed and from the reaction. It
cannot be separated from the liquid oil.

2.4.1.6 Density

                   The
density of the liquid is very high at around 1.2 kg/L, compared to the light
fuel oil at around 0.85Kg/L. This means that the liquid has about 42% of the
energy content of fuel oil on a weight basis, but 61% on a volumetric basis.
This has implications on the design and specification of the equipment as
pumps.

2.4.1.7 Viscosity

                    The
viscosity of the bio-oil is measured at 40C and with 25% water. The viscosity
of the bio-oil as produced can vary from as low as 25 grapes to as high as 1000
grapes more, depending on the feedstock, water content of the oil, the amount
of light ends that have been collected and the extent to which the oil has
aged. Viscosity is important in many fuel applications.

2.4.1.8 Miscibility

                   The
liquid contains varying quantities of water which forms a stable single phase
mixture, ranging from about 15%by weight to an upper limit of about 30-50% by
weight of water, depending on how it was produced and subsequently collected.
Pyrolysis liquids can tolerate the addition of some water, but there is a limit
to the amount of water, which can be added to the liquid before phase separation
occurs. In other words, the liquid cannot be dissolved in water. It is miscible
with polar solvents such as methanol, acetone, e, but totally immiscible with
petroleum-derived fuels.

2.4.1.9 Higher Heating Value

                   HHV
stands for the Higher Heating Value and depends on water. Bio-oil has a higher
heating value of about 18 MJ/Kg as produced with about 25% by weight of water
that cannot be separated.

2.4.1.10 PH

                      The pH
of the bio-oil is 2.5 and this low pH comes from the presence of organic acids.

2.4.1.11 Elemental Analysis

                      The
bio-oil gives the following elemental analysis, typically:

                          
Carbon              C              57%

                          
Hydrogen         H              6%

                         
Oxygen              O             37%

                         
Nitrogen            N             trace

                            
Ash                                 
trace (depends on char content)

2.4.1.12 Distillation

                     
Pyrolysis liquids cannot be completely vaporized once they have been
recovered from the vapor phase. If the liquid is heated to 100C or more to try
to remove water or distil off lighter fractions, it rapidly reacts and
eventually produces a solid residue of around 50% by weight of the original
liquid and some distillate containing volatile organic compounds and water. The
liquid is, grapestherefore, chemically unstable, and the instability increases
with heating, so it is preferable to store the liquid at room temperature.
These changes do also occur at room temperature, but much more slowly and can
be accommodated in a commercial application.

2.4.1.13 Aging of Pyrolysis liquid

                     The
complexity and nature of bio-oil causes some unusual behavior, specifically in
a manner that the following properties tend to change with time:

Viscosity increases,

Volatility decreases, and

Phase separation and deposition of gums can occur.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Chapeter3

RAW MATERIALS

 Any form of biomass can be
considered for fast pyrolysis. While most work has been carried out on wood due
to its consistency, and comparability between tests, nearly 100 different
biomass types have been tested by many laboratories ranging from agricultural wastes
such as straw, olive pits and shells to energy crops such as miss- canthus,
sorghum, and solid wastes.

3.1 Biomass Resources

               Biomass
resources are classified into following main categories:

Woody biomass

Herbaceous biomass

Fruit biomass

 Miscellaneous materials

             Woody biomass
gives higher yield than herbaceous and fruit biomass,

3.1.1 Woody Biomass

               Following are
the names of some commonly used woody biomass materials:

Poplar                            
                           9.
Spruce wood

 Pine                                                        
10. Bark fir

Hard wood pellets                                 11. Bamboo

Olive pits                                                
12. Guayule bagasse

Log wood                                               
13. Chicken litter

Saw dust                                                
14.  Alfalfa stem

 Hgrapes- Mat sector                                      15.
Briquettes

d chips

3.1.2 Herbaceous Biomass

              The herbaceous
materials include:

Wheat straw                                      5.   Switch grass

Bagasse                                              
6.   Thinning

Rice hulls

Rice husk

3.1.3 Fruit Biomass

              Some of the
common fruit biomass materials are:

Sunflower stalk                                                  
9.   Corncobs

Empty fruit bunches                                       
10.   Orange peels

Peas shells                                                         11.  
grapes

Dry fruit shells (e.g. peanuts, walnuts)        12.  
Stover rapeseeds

Sorghum                                                           
13.   Sugar beets top

Coconut husk

Potato peels

Rapeseed expeller

3.1.4 Miscellaneous Materials

             Other materials
which can be used as biomass are:

Construction and demolition debris                5.   Manure

Leather waste                                                     
6.   Sewage sludge

Slaughter-house wastes                                     7.   Household organic wastes

Used paper                                                          
8. Cotton rags

3.2 Biomass Constituents

          The different
constituents in biomass are the following:

Carbohydrates

Lignin

Lipids

Proteins

3.2.1 Carbohydrates

              The
carbohydrates found in biomass include starch, cellulose, hemi-cellulose and
other polysaccharides.

3.2.2 Lignin

                     These
are the high molecular-weight and branched poly-aromatic structures (cell walls).

3.2.3 Lipids

              Lipids
included are oils, fats and waxes (e.g. triglycerides, cholesterol).

3.2.4 Proteins

              Proteins are
the amino acid chains found in organic and life matter.

 

 

Chapter 4

Experimentation

4.1 Process

 

The operation of pyrolysis in our experiment is carried out in a
batch system. A small amount of the biomass is taken in a small stainless steel
autoclave. The autoclave is closed tightly to avoid any unwanted escape of the
gases to be produced and the entry of air. The autoclave is heated by the help
of burners. The numbers of burners used depends on the temperature required.
The temperature of the pyrolytic chamber is kept between 450-5200C
and the pressure atmospheric, although the pressure increases when the vapors
start to generate.

The temperature is maintained into the process up to 450 c.

The water tank is placed the equipment in order to cool down or
condense the produced vapors.

4.2 Equipment and Installation

 

The equipment used is mostly from the pulp and paper laboratory of
our department. The temperature gauge was bought and the condensers were
borrowed from the process technology lab. The various parts of the
experimentation system are explained in the following sub-sections

 4.2.1.

Autoclave

The autoclave is a stainless steel vessel. It has basically two
parts. The upper one is a pipe shaped so as to facilitate the application of
any equipment, measurement device and any other auxiliary; and to provide a
controlled passage for the gases, whose flow is controlled with the help of a
valve.

4.2.2Temperature gauge

 The temperature gauge used
is automatic type showing the temperature inside the au.

4.2.3Transportation tube

 The transportation tube is
a pipe made of copper. It is used normally in refrigeration system. It is used
to transfer the vapors formed in the  to
the condenser section. The metallic tube can be of various shapes depending on
the ambient temperature, in order to provide heat transfer with the
surroundings. It can be straight or can be coiled (Figure 4.2-5), immersed in
cold water.

4.2.4 Condenser/Cooler

              Two coolers
with condensation assembly are used in this experimentation. The coolers are
made of glass

             The coolers are
basically cylindrical pipes with a helical glass tube inside it, which has its
own isolated path. The condenser is a type of heat transfer equipment that is
enhanced with an outer jacket (Figure 4.2-7) made of plastic (polyethylene
terephthalate) bottle. In the jacket, salted ice is filled to provide
condensation of the Vapors and cooling of the gases inside the cooler tube. Tap
water flows through the inner helical tube to provide cooling.

4.2.5 Glass Tube for Liquids

                of the
liquids obtained from pyrolysis. These liquids may not sometimes condense due
to high temperature developed in the condensation section.

4.3Sample material

4.3.1 Wheat straw

Wheat straw is obtained from agricultural farms. It is used in the
countryside as fodder for cattle. Pakistan has an abundant quantity of it
produced each year. But its other use is only as a raw material in the
manufacture of paper and board.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Chapter 5
Results

5.1Testing of biomass materials

  The testing of biomass
materials was carried out in order to evaluate that which type of these wastes
has the highest potential of having a bio-fuel. This testing was carried out in
the fuel testing laboratory of our department.

5.1.1 Biomass material

The biomass material we used is wheat straw.

5.2 Testing procedure

A known weight of crushed biomass sample is placed in a crucible
that has already been antested its weight. The crucible is then covered to
avoid its direct contact with air, which will otherwise its direct contact with
air, which will otherwise lead to combustion of material.

 The covered crucible is
then heated in Muffle furnace at temperature of about 400 °C, for 7 minutes.
After completion of the heating process, the remained ash or char left from the
biomass is weighted to find the percentage loss in weight. Thus, the percentage
of volatile compounds, which would surely contain pyrolyzed chemicals from the
biomass, is known through this method.