This document summarizes research on downdraft biomass gasification. It discusses the objectives of minimizing tar and ash particulate in syngas, design cost, and energy density. Literature on downdraft gasifiers finds air flow rates vary from 1.8-3.4 m3/hr, moisture content from 4-12%, and biomass consumption from 1.0 to 3.6 kg/hr. Pros include low tar production and sensitivity, while cons are tall design and moisture sensitivity. Future work involves further research, field visits, and design parameters for gasification.

1. 1
DOWNDRAFT
BIOMASS-GASIFIER
V.V.P ENGINEERING COLLEGE, RAJKOT
Department of Chemical Engineering
Prepared By:
Bhargav Dhameliya (160470105012)
Vivek M. Faldu (160470105013)
Kevin Chothani
(160470105009)
Vivek Kansaraga (170473105003)
Nikul Khunt
Guide : Jilesh M. Pandya

2. •Introduction
•Modified objective of work
•Literature survey
•Conclusion
•Future Work
•References

3.  World is facing a great problem of energy crises, because of overuse of
conventional fuels in automobiles, power generation and various thermal
applications.
 Modern agriculture is an extremely energy intensive process.
 Gasifier is a unit which produces inflammable gases by the pyrolysis of
wood and similar biomasses.
 Conversion technologies for utilizing biomass can be separated into four
basic categories: Direct combustion processes, Thermochemical processes
, Biochemical processes and Argo-chemical processes .
 Thermochemical conversion of biomass(Pyrolysis, Gasification,
Combustion) is an ideal choice for small-scale gasification processes
where the maximum electricity generated is about 500kW.

4.  Biomass gas is expected to play an important role in meeting the existing
gap between the energy supply and energy demand.
 It is considered as economically viable feed stock.
 Gasifier fuel can be classified good or bad according to…
Energy content
of fuel
Bulk Density
Moisture
content
Dust content
Tar content
Ash and
Slagging
characteristic

5.  We’ve selected DOWN-DRAFT gasifier in which main objective is to
mitigate TAR and ASH particulate in syngas.
 Minimize the design cost of Biomass gasifier.
 Maximization of energy density of producer gas.
 Studying the characteristic value of Biomass and selection of it.

7. Air
pollution
Dust
pollution
Biomass
ash
TAR
yield
CO
poisoning
Water
pollution

9.  In downdraft gasifiers, pyrolyzed gas and moisture generated in
pyrolysis and drying zone, respectively flow downwards.
 Pyrolysis gases pass through a combustion zone followed by hot bed
of char which is supported by a grate.
 Due to high temperature of combustion and reduction zone, TAR of
the pyrolyzed gas mixture are partially broken down.
 According to literature survey of Downdraft gasifier, air flow rate is
varied from 1.8-3.4 m3/hr, moisture content varied from 4-12% and
biomass consumption rate is found to vary from 1.0 to 3.6 kg/hr.

10. [10]
Fuel
Volume %
C.V.
MJ/m3
TAR
g/m3
ASH
%
Bulk
density
Kg/m3
Moisture
content
%
Experience
CO H2 CH4 CO2
Coconut
shell
19-
24
10-
15
- 11-15 7.02 3 0.8 435 11.8 Excellent fuel, No slag
formation.
Corn
cobs
18.6 16.
5
6.4 6.39 6.29 7.24 1.5 304 11 Excellent fuel, No slag
formation.
Pressed
sugarca
ne
15-
18
15-
18
- 12-14 5.30 - 1.6 52 - Slagging minor
Wood
chips
17-
22
16-
20
2-3 10-15 5-5.86 6.24 6.26 166 10.8 Bridging and slagging
Coconut
husk
16-
20
17-
19.
5
- 10-15 5.80 - 3.4 65 - Slag on grate but no
operation problem.

11. PROS
 low sensitivity to charcoal dust and tar content of fuel.
 Lesser TAR production.
 Low energy consumption technology.
 Can be used to run I.C. , S.I. and C.I. engines.
CONS
 Design tends to be tall.
 Not feasible for very small particle size of fuel.
 Removal of TAR accumulation.
 Moisture sensitive

12.  Study of more research papers
 On site field visit (Radhe energy-Rajkot and Ankur technology- Baroda)
 Critical analysis of required design parameters for gasification process.
 Design of downdraft gasifier.

13. 1. Rohit Raj, Vivek k, Parvathy Venugopal, Vishnu Vijayan, Bio gasifier, IJIRT Volume 2,
May 2016
2. Amit Kumar Mishra, R N Singh, Pratyush Pingita Mishra, Effect of Biomass
Gasification on Environment, Mesopotamia Environmental Journal volume 1, 2015
3. Elango Balu, J.N. Chung, System characteristics and performance evaluation of a
trailer-sacle downdraft gasifier with different feedstock, Bioresources technology, may
2015
4. Pratik N. Sheth, B.V. Babu, Experimental studies on producer gas generation from
wood waste in a downdraft biomass gasifier, Bioresources technology, February 2009
5. Maria Puig-Arnavat, Joan Carles Bruno, Alberto Coronas, Review and analysis of
biomass gasification models, Renewable and Sustainable Energy Reviews, May 2010
6. Pengmei L, Zhenhong Yuan, Longlong Ma, Chuangzhi W u, Young Chen, Jingxu Zhu,
Hydrogen-rich gas production from biomass air and oxygen/steam gasification in a
downdraft gasifier, Renewable Energy 32(2007)

14. 7. Foly, and Bamard, G., Biomass gasification in developing Countries. Technical
Report No. 1, Earthscan, London, 1983.
8. Biomass Energy Consultants and Engineers (BECE), unpublished data, 1982
9.I. Janajresh, M. Al Shrah, Numerical and experimental investigation of downdraft
gasification of wood chip, Energy Conversion and Management
10. Anil K. Rajvanshi, Biomass Gasification, history of gasification research
(NARI),1986
11. Pengmei Lv, Zhenhong Yuan, Chuangzhi Wu, Bio-syngas production from
biomass catalytic gasification, Energy Conversion & Management, 26 Decmember
2006
12. Dipal Baruah, D.C Baruch, Modelling of biomass gasification: A review,
Renewable and sustainable Energy Reviews,19 July 2014
13. David Sutton, Barian Kelleher, Julian R.H Ross, Review of literature on
catalysts for biomass gasification, Fuel Processing Technology, 22 May 2001