2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
- 109 -
efficiency of 43% for gasification of wood shavings using
preheated air as the gasifying medium in a circulating
fluidized bed (CFB) gasifier operating at 0.18 MPa
pressure was reported. Similarly Lundquist [5] found an
efficiency of 82.43% for wood waste-fed circulating
fluidized bed gasifier with preheated air at 2.48 MPa. The
results reported in [4] and [5] were for demonstration/
commercial units. In [6] an efficiency of 57% for
bubbling fluidized bed (BFB) pilot plant gasifier using
air-steam as the gasification agent has been reported.
Sanchez and Silva [7] have reported gasifier operation
and design parameters for maximum efficiency
conditions for fluidized bed gasifiers fed with rice husk,
sawdust, spent coffee grounds and bagasse, being
operated at the State University of Campinas, Brazil.
They have reported a maximum efficiency of 65% at an
ER of 0.55 for rice husk and 41% at an ER of 0.25 for
saw dust fed fluidized bed gasifier. The bed temperatures
for rice husk and saw dust were 759 and 777
q
C,
respectively. Corella and his team [3] have shown that the
use of in-bed dolomite during the fluidized bed
gasification of petroleum coke shows a slight-parabolic
increase in the apparent thermal efficiency with ER. The
efficiency was found to pass through a maximum with the
increase in ER giving around 75% at an ER ~ 0.34. The
results from the present study are in general agreement
with the reported values in literature, although on a
higher side.
IV. C
ONCLUSION
A laboratory scale fluidized bed gasifier was designed,
fabricated and installed. The operational details of the
same are presented. The gasifier was operated on village
rice husk and saw dust as two feed stocks. Based on the
high heating values of gaseous end product and feedstock
the thermal efficiency of gasification process was
evaluated at different equivalence ratios and fluidization
velocities. It was found that maximum thermal efficiency
was 57.04% for rice husk at ER=0.4 and 72.30% for saw
dust at ER=0.25. The operational experience gained from
this lab scale unit would be beneficial for pilot plant
operation as envisaged for future installation.
R
EFERENCES
[1]
Gangavati, P.B., Mishra I.M.; Prasad B.:
Characterization
of biomass for gasification in a fluidized bed
, Proc. of
National Conference on Recent Trends in Energy
Engineering-NACOE 03, held at E.R. Nagar Kovilpatt Tk.
Thoothukudi, Tamilnadu, India on October 11-12, 2009,
pp 198-203.
[2]
Gangavati, P.B.:
Biomass Characterization and
Gasification in a Fluidized Bed
, Ph.D. Thesis, Department
of Chemical Engineering, Indian Institute of Technology,
Roorkee, India, 2002.
[3]
Corella, J.; Caballero, M.A.; Aznar, M.P.; Toledo, J.M.:
Typical gas composition and characteristics in gasification
with air of carbonaceous residues in circulating and
atmospheric fluidized bed
,” Proc
. of Petro-Tech India, New
Delhi, Jan. 9-11, 2001.
[4]
Strom, E.; Liinanki, L.; Sjostrom, K.:
Gasification of
Biomass in the MINO Process
, Technical Bulletion of the
Royal Institute of Technology, Stockholm, Sweden, 1982.
[5]
Lundqvist, R.G.:
The IGCC demonstration plant at
Varnamo
, Bioreso. Technol., 46, 1993, pp. 49-53.
[6]
Bridgewater, A.V.:
The technical and economic feasibility
of biomass gasification for power generation
, Fuel, 74 (3),
1995, pp. 631-653.
[7]
Sanchez C.G.; Silva, E.L.:
Biomass fluidized bed
gasification research in the State University of Campinas
,
Energy for Sustainable Development, 1(4), 1994, pp. 31-
34.
