This document summarizes a student group's biomass gasification project. It includes an introduction, objectives to fabricate a biomass gasifier unit and simulate the gasification process. It describes the process flow diagram and different zones of a gasifier. Equations for reactions in each zone are provided. The document also includes specifications for the designed gasifier and cyclone separator. Simulation results at different temperatures are presented.

1. FYP Presentation #04
Advisor: Dr. Khurram Imran Khan
Co. Advisor: Dr. Roman Zaib Babar
GROUP MEMBERS
Ali Manshah 2013040
Izaz Ahsan 2013156
Obaid Ullah 2013297
DATE: February 1, 2017

2. 1. Introduction
2. Objectives
3. Fixed Bed Biomass Gasifier
4. Process Flow Diagram
5. Relative parameter for fire tube designing
6. Gasifier Different zone
7. Cyclone Separator
8. References

3. Biomass gasification is a chemical process that convert
biomass into useful convenient gaseous fuel. It has emerged as a
promising technology to fulfill the increasing energy demands of the
world as well as to reduce significantly the volume of Biomass waste
generated in developing societies.
Gasification produce gases like CO,CO2, H2 and CH4; these gas released
are called Syngas.
Gasification technology can be used for:
1. Household Fuel
2. Electricity and Steam Generation
3. In internal combustion engines as a fuel
In a gasifier, the biomass undergoes several different processes like
drying, pyrolysis, combustion and gasification process

4.  Fabrication of biomass gasifier unit to
transfer solid fuels into gaseous fuel.
 Simulation of biomass gasification unit for
finding the optimum parameters of the
process.

6. Drying Zone
Oxidation Zone
Pyrolysis Zone
Reduction Zone
22”
2”
2”
3”
4”
10”
17”
1”
6”
1”

7. Ash-pit
Drying Zone
Oxidation Zone
Pyrolysis Zone
Reduction Zone
22”
H=2”
F=2”
E=3”
A = 4”
B = 10”
17”
G=1”
C=6”
1”
D
I
J

8. • Diameter of the tube.
• Length of the firetube
• Place of air inlet(s).
• Surface area of air
inlet(s)/velocity of
entering air
Insides
Diameter of
firetube
(inches)
Minimum
Length of
firetube
(inches)
Engine
Power
(hp)
2 16 5
4 17 15
6 17 30
7 18 40
8 20 50
9 22 65
10 24 80

10. 1. DRYING ZONE
• The topmost zone contains unreacted biomass (fuel)
through which air and oxygen enters. This zone act as a
drying zone for fuel.
• Biomass fuels usually contain 10%–35% moisture. When
biomass is heated to about 100 °C, the moisture is
converted into steam.

11. • At temperatures above 250°C, the biomass fuel
starts pyrolysing. The details of these pyrolysis
reactions are not well known, but one can guess
that large molecules (such as cellulose, hemi-
cellulose and lignin) break down into medium
size molecules and carbon (char) during the
heating of the feedstock.

12. • The pyrolysis products flow downwards into the
hotter zones of the gasifier. Some will be burned in
the oxidation zone, and the rest will break down to
even smaller molecules of hydrogen, methane,
carbon monoxide, carbon dioxide, water etc.
• Biomass + O2 → Char+CO+H2+H2O+CO2+CH4+N2

13. • The third zone is made up of charcoal from the
second zone. Hot combustion gases from the
pyrolysis region react with the charcoal to convert
the CO2 and H2O (v) into CO and H2.
• The main components in the gas produced in the
partial oxidation zone are H2, CO and O2 Therefore;
the main reactions are apparently as follows.

14. • H2 + ½ O2 → H2O -241.1 kJ/mol
• CO + ½ O2 → CO2 –111.4 kJ/mol
• C + O2 ↔ CO2 -393.5 kJ/mol

15. • The reaction products of the oxidation zone (hot
gases and glowing charcoal) move downward into
the reduction zone.
• In this zone the sensible heat of the gases and
charcoal is converted as much as possible into
chemical energy of the syngas. The end product of
the chemical reactions that take place in the
reduction zone is a combustible gas which can be
used as fuel gas in burners and after dust removal
and cooling is suitable for internal combustion
engines.

16. • C (char) + O2 → CO2 - 401.9 kJ/mol
• C (char) + CO2 → 2CO + 164.9 kJ/kmol
• C (char) + H2O → CO+H2 + 122.6 KJ/Kmol
• C (char) + 2H2 → CH4 0 KJ/Kmol
• CO + H2O → CO2 + H2 + 42.3 kJ/kmol
(water gas shift reaction)

17. • DESCRIPTION
• This is the separator mainly used for the separation
of solids from the fluids. It mainly consists of the
tangential inlet to feed the materials inside the
chamber.
• It consists of solids out let and fluid out let, it
through the fluid through one side and the
separated solids through the other out let.

18. • PRINCIPLE
• In the cyclone separator the centrifugal force is
used to separate tar, dust and solid particles from
the syngas. The separation depends not only on the
particles size but also on the density of the
particles.
• Hence depending on the syngas velocity the cyclone
separator can be used to separate all types of the
particles, out to remove, and allows fine particles to
be carried through with the fluid.

19. The cyclone consists of four main
parts:
1. Inlet (2” D): Tangential inlets
produce swirling motion which are
preferred for the separation of
solid particles(Fc = mv2/r) from
gases.
2.Separation chamber(L 14”, top D 8”,
bottom D 1”):
Angle of Cyclone= ( height of cone X
360) / length of base
=10 X 360 / 20
=180 degree
3. Vortex finder (2”D, 7”down):
pressure drop directly
proportional to vortex finder
length.
4. dust chamber:
Lies below the
underflow orifice

20. 1) Rectangular metal box (length 14”,width 11”, height 14”)
2) Inlet pipe (D 2”)
3) Outlet pipe (D 1”)
4) Divider plate (length 11.5”,height 12”)
5) Bottom plate (sieve size ¾ “ hole)

21. • Filter media, like hay, is
placed inside the two
chamber.
• Syngas entered into the
top of one chamber and
leave from the top of
another chamber.
• All this syngas sucks by a
blower .
• All the joints should be air
tight. To ensure this we
have used welding in
addition of high
temperature silicon.

22. • Temperature=25 C
• Pressure=740mm Hg
PRODUCT OF GASIFICATION
• Producer gas
• Ashes (Ash + Carbon = Ashes)
• Tar
• Soot

23. WOOD COMPOSITION
COMPONENTS
WEIGHT % SYNGAS COMPOSITION
COMPONENTS
VOLUME %
C 50 CO2 7
O 42 H2 14
H2 6 CH4 2.5
N2 1 CO 21
N2 53

24. • The substance of a solid fuel is usually composed
of the elements C, H2 and O2.
• In addition there may be N2 and S, but since these
are present only in small quantities they will be
disregarded in the following discussion.
• In the type of gasifiers considered here, a part of
the solid fuel is heated by combustion. The
combustion gases are then reduced by being
passed through a bed of fuel at high temperature.

25. • Oxidation, or combustion
• C + O2 → CO2 - 401.9 kJ/mol
• H2 + ½ O2 → H2O -241.1 kJ/mol
• C + H2 → CO + H2O -241.1 kJ/mol

26. Waste wood Wood chips bagasse
Peat Corn Cob Coconut shell

28. ID Type Name Formula
O2 CONV OXYGEN O2
CO CONV CARBON-MONOXIDE CO
H2 CONV HYDROGEN H2
CO2 CONV CARBON-DIOXIDE CO2
H20 CONV WATER H2O
H2S CONV HYDROGEN-SULFIDE H2S
N2 CONV NITROGEN N2
CH4 CONV METHANE C4H4
C6H6 CONV BENZENE C6H6
C SOLID CRBON-GRAPHITE C
S SOLID SULFUR S
COAL NC ...... ……
CHAR1 NC …… ……
CHAR2 NC ….. ……
ASH NC …… ……

29. Feedstock Parameter Value Unit
Wood chips
Flow rate 76.66 G/s
Temperature 505.22 K
Pressure 24 Atm
Diameter of particle 350 µm
Velocity entering into gasifier 3 M/s
Oxygen
Ratio of oxygen to coal flow rates 0.866 Dimensionless
Temperature 298 K
Pressure 24 Atm
Steam
Ratio of steam to coal flow rates 0.241 Dimensionless
Temperature 696.67 K
Pressure 24 Atm

30. Yield of Wood Pyrolysis used in the model
Pressure(1atm) Pressure(24atm)
Components Yield(mass basis) Yield(mass basis)
CO 0.0059 0.0055
H2 0.0084 0.0080
CO2 0.003 0.00286
H2O 0.0079 0.00747
H2S 0.0094 0.0087
N2 0.0035 0.00347
CH4 0.1637 0.1601
C6H6 0.071 0.0701
Char 0.7272 0.7201
Total 1 1

31. 0
10
20
30
40
50
60
70
650 700 750 800
MolarComposition(%)
Temp (°C)
Temp(C) vs syngas composition
H2
CO
0
5
10
15
20
25
650 700 750 800
MolarComposition(%)
Temp (°C)
Temp(C) vs syngas composition
CO2
CH4

32. 0
10
20
30
40
50
60
70
0 1 2 3
Percentageofcomposition
Steam to biomass ratio
S/B vs syngas composition
H2
CO
0
5
10
15
20
25
0 1 2 3
Percentageofcomposition
Steam to biomass ratio
S/B vs syngas composition
CO2
CH4

33. Temp (K) 1423.2
Components Flow rate(g/s)
CO 123.44
H2 5.99
CO2 10.24
CH4 0.24
H2S 1.04
N2 0.54
Carbon conversion(%) 98.69
Temp (K) 1771.2
Components Flow rates(g/s)
CO 127.71
H2 5.96
CO2 6.462
CH4 0.13
H2S 1.405
N2 0.54
Carbon conversion(%) 99.95

34. Proximate analysis(%)
Wood chips Waste wood Coal
Moisture 6.2 7.8 3.93
Volatile matter 75.70 76.23 25.5
Ash 6.90 3.97 40
Fixed Carbon 11.2 12 30.57

35. • LaFontaine, H., & Zimmerman, G. P. (1989). Construction of a simplified
wood gas generator for fueling internal combustion engines in a petroleum
emergency (No. ORNL-6404).OAK RIDGE NATIONAL LAB TN.
• Bhavanam, A., &Sastry, R. C. (2011). Biomass Gasification Processes in
Downd raft Fixed Bed Reactors: A Review. International Journal of
Chemical Engineering and Applications, 2(6), 425.
• Joshi, R., &Kulkarni, B. (2012).Simulation of biomass gasification reactor
for fuel in gas turbine. International Journal of Chemical Sciences and
Applications, 3, 232-240.
• Jayah, T. H., Aye, L., Fuller, R. J., & Stewart, D. F. Simulation Study of a
Down-Draft Wood Gasifier Used to Produce Thermal Energy for Tea
Drying.Renewable Energy Transforming Business, 639-646.