Fyp 4 presentation

FYP Presentation #04

Advisor: Dr. Khurram Imran KhanCo. Advisor: Dr. Roman Zaib Babar

GROUP MEMBERS

Ali Manshah 2013040Izaz Ahsan 2013156 Obaid Ullah 2013297

DATE: February 1, 2017

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

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 Fuel2. Electricity and Steam Generation3. In internal combustion engines as a fuelIn a gasifier, the biomass undergoes several different processes like drying, pyrolysis, combustion and gasification process

Fabrication of biomass gasifier unit totransfer solid fuels into gaseous fuel.

Simulation of biomass gasification unit forfinding the optimum parameters of theprocess.

Drying Zone

Oxidation Zone

Pyrolysis Zone

Reduction Zone

22

”

2”

2”

3”

4”

10”

17

”

1”

6”

1”

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

• Diameter of the tube.

• Length of the firetube

• Place of air inlet(s).

• Surface area of airinlet(s)/velocity ofentering 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

1. DRYING ZONE

• The topmost zone contains unreacted biomass (fuel)through which air and oxygen enters. This zone act as adrying zone for fuel.

• Biomass fuels usually contain 10%–35% moisture. Whenbiomass is heated to about 100 °C, the moisture isconverted into steam.

• At temperatures above 250°C, the biomass fuelstarts pyrolysing. The details of these pyrolysisreactions are not well known, but one can guessthat large molecules (such as cellulose, hemi-cellulose and lignin) break down into mediumsize molecules and carbon (char) during theheating of the feedstock.

• The pyrolysis products flow downwards into thehotter zones of the gasifier. Some will be burned inthe oxidation zone, and the rest will break down toeven smaller molecules of hydrogen, methane,carbon monoxide, carbon dioxide, water etc.

• Biomass + O2 → Char+CO+H2+H2O+CO2+CH4+N2

• 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.

• H2 + ½ O2 → H2O -241.1 kJ/mol

• CO + ½ O2 → CO2 –111.4 kJ/mol

• C + O2 ↔ CO2 -393.5 kJ/mol

• The reaction products of the oxidation zone (hotgases and glowing charcoal) move downward intothe reduction zone.

• In this zone the sensible heat of the gases andcharcoal is converted as much as possible intochemical energy of the syngas. The end product ofthe chemical reactions that take place in thereduction zone is a combustible gas which can beused as fuel gas in burners and after dust removaland cooling is suitable for internal combustionengines.

• 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)

• DESCRIPTION

• This is the separator mainly used for the separationof solids from the fluids. It mainly consists of thetangential inlet to feed the materials inside thechamber.

• It consists of solids out let and fluid out let, itthrough the fluid through one side and theseparated solids through the other out let.

• PRINCIPLE

• In the cyclone separator the centrifugal force isused to separate tar, dust and solid particles fromthe syngas. The separation depends not only on theparticles size but also on the density of theparticles.

• Hence depending on the syngas velocity the cycloneseparator can be used to separate all types of theparticles, out to remove, and allows fine particles tobe carried through with the fluid.

The cyclone consists of four mainparts:

1. Inlet (2” D): Tangential inletsproduce swirling motion which arepreferred for the separation ofsolid particles(Fc = mv2/r) fromgases.

2.Separation chamber(L 14”, top D 8”,bottom D 1”):

Angle of Cyclone= ( height of cone X360) / length of base

=10 X 360 / 20=180 degree

3. Vortex finder (2”D, 7”down):pressure drop directly

proportional to vortex finderlength.

4. dust chamber:Lies below the

underflow orifice

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)

• 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.

• Temperature=25 C

• Pressure=740mm Hg

PRODUCT OF GASIFICATION

• Producer gas

• Ashes (Ash + Carbon = Ashes)

• Tar

• Soot

WOOD COMPOSITION COMPONENTS

WEIGHT % SYNGAS COMPOSITIONCOMPONENTS

VOLUME %

C 50 CO2 7

O 42 H2 14

H2 6 CH4 2.5

N2 1 CO 21

N2 53

• The substance of a solid fuel is usually composedof the elements C, H2 and O2.

• In addition there may be N2 and S, but since theseare present only in small quantities they will bedisregarded in the following discussion.

• In the type of gasifiers considered here, a part ofthe solid fuel is heated by combustion. Thecombustion gases are then reduced by beingpassed through a bed of fuel at high temperature.

• 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

Waste wood Wood chips bagasse

Peat Corn Cob Coconut shell

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 …… ……

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

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

0

10

20

30

40

50

60

70

650 700 750 800

Mo

lar

Co

mp

osi

tio

n (

%)

Temp (°C)

Temp(C) vs syngas composition

H2

CO

0

5

10

15

20

25

650 700 750 800

Mo

lar

Co

mp

osi

tio

n (

%)

Temp (°C)

Temp(C) vs syngas composition

CO2

CH4

0

10

20

30

40

50

60

70

0 1 2 3

Pe

rce

nta

ge o

f co

mp

osi

tio

n

Steam to biomass ratio

S/B vs syngas composition

H2

CO

0

5

10

15

20

25

0 1 2 3

Pe

rce

nta

ge o

f co

mp

osi

tio

n

Steam to biomass ratio

S/B vs syngas composition

CO2

CH4

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

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

• 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.