|
|
|
|
|
|
 |
Vertical Shaft Brick Kiln
- For cleaner brick production
"Conventional
burnt clay bricks will continue to be the main walling
material for meeting the huge demand for housing in the
foreseeable future, notwithstanding substantial efforts
to develop alternatives. Current technologies for brick
production such as clamps, downdraught kilns and Bull’s
Trench Kilns consume large quantities of fuel such as
coal, firewood and other biomass materials. The
devastating effect of the pollution caused by huge
amount of emissions from the brick industry has
attracted the attention of regulatory agencies who have
issued deadlines after which the polluting kilns are to
"clean up or close down." In the Agra
trapezium, the Hon'ble Supreme Court of India has
enforced a total closure of brick kilns."
The search for cleaner brick production technologies has
led to the identification of Vertical Shaft Brick Kiln (VSBK)
technology. The Vertical Shaft Brick Kiln technology
originally developed in China is an energy efficient,
environment friendly and economically viable means to
produce quality bricks. It has been adapted to Indian
conditions and successfully field tested at 4
geographical locations. Further, it has received
certification from the Central Pollution Control Board (CPCB)
for operations in accordance with stipulated
environmental norms.
Major Advantages
of VSBK technology
 |
It
represents a extremely energy-efficient,
low-cost method of firing bricks. The fired
quality is high with very low wastage. |
|
Emissions
from the kiln are well within acceptable limits |
|
The
kilns require very little maintenance once
constructed and are not complicated to build. |
|
The
kiln is very compact not requiring a large area
of land and can be built near to the clay
source. |
|
The
construction cost is low. |
|
The
kiln is not affected by variations in the
weather as long as dry green bricks are
available. |
|
More
than one shaft allows for firing flexibility to
cope with seasonal and economical variations in
brick production and demand. |
|
The
kiln is highly suitable for use where fuel is
incorporated into the brick. |
Salient features of
existing VSBK’s in India
|
Location |
Organization |
No
of Shafts |
Shaft
Size |
Production
Capacity |
|
VSBK
1 |
Datia,
M.P. |
Development
Alternatives, NGO |
2 |
1
x 1 m
1
x 1.5 m |
~5000
per.day
|
|
VSBK
2 |
Kankia,
Orissa |
Gram
Vikas, NGO |
2 |
1
x 1.75 m
1
x 1.75 m |
~
7000 per day |
|
VSBK
3 |
Palghat,
Kerala |
Comtrust,
NGO |
2 |
1
x1.75 m – 3nos
1x
2 m – 1no |
~14500per
day |
|
VSBK
4 |
Pune,
Maharashtra |
MITCON-DAMLE
Pvt.
Ltd. |
2 |
1x
2 m – 1 no
1.25
x 2 m – 1no |
~
9500 per day |
|
VSBK
5 |
Gwalior,
M.P. |
Yade
Brick Industries Pvt. Ltd. |
2+2 |
1
x 2 m – 4nos |
~
16000 per day |
|
VSBK
2000 Best practice + R&D Kiln |
Datia,
M.P |
Development
Alternatives |
2(BPE)
+1 (R&D) |
BPE
1.25x1.75 m – 2nos +
R&D
1x1.5 m – 1 no |
8500
+ 3000 per day |
Notes
Upscaling
to achieve higher brick production (5000 to 9500
bricks per day)
Progressive increase in shaft dimensions from 1
m x 1m to 1.25 m x 2 m |
 VSBK Construction –
Basic Features
The VSBK consists
of one or more shafts located inside a rectangular brick
structure. the shafts are 1 m wide with nominal lengths
of 1 m, 1.5 m, 1.75m or 2m. The inside surface is a
brick wall, sometimes lined with refractory brick. The
gap between the shaft wall and the outer kiln wall is
filled with insulating materials like clay and rice husk
etc.
The shaft is loaded from the top with a number of
batches of bricks for firing. Each batch contains four
layers of bricks set in a pre-determined pattern. The
stack of bricks rest on square support bars (which can
be removed or inserted) resting on a pair of horizontal
beams across the arches in the unloading tunnel.
VSBK – How It
Works
During operation,
one batch of dried green bricks is loaded at the top at
a time. A weighed quantity of powdered coal (less than 6
mm) is spread on each layer uniformly to fill the gaps.
The brick unloading is done from the bottom using a
trolley which runs on rails along the length of the
unloading tunnel. Lifting and lowering of the trolley is
done using single screw unloading mechanism. For
unloading, the trolley is lifted so that whole stack of
bricks in the shaft rests on it. Further slight lifting
of the trolley (and the stack) releases the support
bars, which are removed from either side. The stack is
then lowered till the layer with openings appears,
through which the support bars are then re-inserted. On
further lowering, the load of the stack is taken by the
support bars except for the batch being unloaded which
comes down along with the trolley which finally rests on
a pair of rails. The trolley is later cooled out along
the rails and the bricks subsequently unloaded and
sorted out to despatch. The next batch is loaded at the
top using green bricks lifted upto the loading platform.
The frequency of unloading – loading from 90 to 150
minutes.
The skill in operation is to keep the firing zone in the
middle of the shaft. The draught of air moving up from
the bottom cools the fired bricks in the cooling zone
and itself gets heated. Maximum temperature of upto 1000o
C are attained in the central firing zone. This
recovery of sensible heat accounts for the high energy
efficiency of the VSBK technology.
VSBK – Financial Implications & Returns
| Project
Details |
|
|
Daily
Production per Shaft |
3750 |
| Number
of Shafts |
2 |
| Daily
Kiln Production |
7500 |
| Number
of days of operation per year |
200 |
| Annual
Production |
15,00,000 |
| Saleable
Production (95%) |
14,25,000 |
| Sale
Price |
Rs.
1100 per 1000 |
|
| Project
Cost |
|
|
Land
(provided by Entrepreneur) |
|
| Tubewell
and Pump |
90,000 |
| Daily
Kiln Production |
25,000 |
| VSBK
(Construction and Equipment) |
4,25,000 |
| Wheel
Barrows |
20,000 |
| Technology
Fees |
50,000 |
| Preoperative
Costs |
40,000 |
| Extruder
(with Installation) |
1,60,000 |
| Working
Capital |
1,55,000 |
| Total |
9,65,000 |
|
| Profitability |
|
|
Sales
Value |
15,67,500 |
| Materials
and Operating Costs |
11,60,000 |
| Marketing
Costs |
71,000 |
| Finance
Costs @ 14% |
1,35,000 |
| Sub
Total |
13,66,000 |
| Profit
before Depreciation and Interest |
2,01,500 |
|
Notes:
1. The figures are typical. The
input and operational costs and
selling price of burnt brick vary
from location to location.
2.
the land requirement for above
would be of the order of 3000 m2
.
|
|
|
|
|
