FIELD OF THE INVENTION
The present invention relates to a system for improving productivity and speed of sinter
machine and a process thereof adapted to control the air-volume distribution along the
length of the sinter machine bed such that the air flow in initial length of the sinter machine
is restricted and also achieve extension of retention time of heat holding of top layer due to
reduction of air volume through the bed. More particularly, the present system is capable to
control the air volume distribution in the sinter machines having length exceeding 60
meters, wherein the air volume control in the initial 40% of length is controlled by the
operation of electrically controlled dampers mounted in the individual wind boxes of sinter
machine such that the air volume saved in the initial length of bed is utilized in the later
part of sinter machine. Such control of air flow/volume along sintering bed length
advantageously increases the sintering speed in the later half of sinter machine bed and
thereby increases the sinter machine productivity. The system of the invention and the
process adapted for air flow control using said system favor increasing the specific
productivity of sinter machine from the existing level of 1.18 to 1.33 t/m2/hr i.e. by about
12% associated with an improvement of Yield of 11% of the top layer of sinter bed, and
thus having prospect of wide application in steel plants.
BACKGROUND ART
It is known in the art of sinter making process in sintering machines that the air flow control
along the sintering bed length plays an important role in productivity and sinter quality.
The iron ore fines are converted to a lumpy porous mass by the sintering process to use
them as input to blast furnace having improved metallurgical properties. In the conventional
practice, it is observed that in absence of any selective control of flow of air volume through
bed in individual wind boxes from below the bed, results in excess air flow through initial
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length of sinter bed and less air volume flow through the latter half of the sinter bed. This
uncontrolled air volume distribution over the sinter bed length leads to loss of sinter
machine productivity. The conventional process thus suffer from imbalance in the air
volume distribution along the sintering bed length because of high volume of air sucked
through initial 30% length of sinter machine resulting in poor sinter quality and low
production from the top half portion of the sinter bed. Further, the existing system is also
not able to provide adequate air flow volume required for the sintering of the bottom portion
of the later half of sinter bed because of excess use of air volume flow in the initial portion
of bed length.
There has been thus a continuous need to optimize the air volume flow control through the
length of the sinter bed during sintering process, such as to favor exact air suction at the
specific zone along the bed length for improved and complete sintering and thereby ensure
better and consistent sinter quality and enhanced productivity of the sinter plant. Also by
the need based rationalization of the air flow volume along the bed length for improving
sintering efficiency, the exhauster blower capacity to suck air is possible to be fully and
gainfully utilized.
OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to provide a system for improving
productivity and vertical sintering speed in sinter machine and a process involving selective
control the air-volume distribution along the length of the sinter machine bed such that the
air flow in initial length of the sinter machine is restricted and the same in the latter half is
increased and also achieve extension of retention time of top layer due to reduction of air
velocity through the bed.
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A further object of the present invention directed to a system for said desired air volume
flow control achieved selectively through electrically controlled damper means installed in
the individual wind boxes below the sinter bed.
A further object of the present invention directed to a system for improving productivity and
vertical sintering speed in sinter machine and a process thereof adapted to control the air-
volume distribution along the length of the sinter machine bed wherein air flow in the initial
40% length of bed is restricted by 30% of the dampers installed in the initial wind boxes.
A further object of the present invention directed to a system for improving productivity and
vertical sintering speed in sinter machine and a process thereof adapted to control the air-
volume distribution along the length of the sinter machine bed, wherein the improvement of
sinter quality of the top layer of sinter bed is achieved by operative control on air volume
flow, by extension of retention time of heat holding of top layer (200mm) at a temperature
of above 1100°C, due to restricted air flow in initial portion.
A still further object of the present invention directed to a system for improving productivity
and quality of sintering and a process thereof adapted to control the air-volume distribution
along the length of the sinter machine bed and increased retention time of the top layer of
sinter bed, is directed to improvement in solid fuel consumption by improving top layer
sinter quality.
A still further object of the present invention directed to a system for improving productivity
and quality of sintering and a process thereof by selective control of air volume distribution
along sinter machine bed length and also increasing the retention time of top layer of bed,
is to achieve high burn through point temperature of >350°C, due to high air volume
available in the later half of sintering machine, favoring also completion of sinter process in
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the machine resulting in better quality of sinter, lower exhauster motor power consumption
due to high temperature of exhaust gas and also efficient cooling of sinter.
SUMMARY OF THE INVENTION
The basic aspect of the present invention is therefore directed to a system for improving
productivity and speed in sintering machine comprising:
means for air volume distribution control adapted for controlling the air volume distribution
along the length of the sinter machine such that the air flow in initial length of the sinter
machine is restricted and extension of retention time of top layer due to reduction of air
volume thorough the bed.
A further aspect of the present invention directed to said system for improving productivity
and speed in sintering machine wherein said means for air volume distribution control
comprises damper controller installed in the wind boxes of sinter machines.
A still further aspect of the present invention directed to a system for improving productivity
and speed in sintering machine wherein the air flow control regime is such that air flow in
initial 40% of length of sinter machine is restricted by 30% of damper of wind boxes of
initial wind boxes.
According to another aspect of the present invention directed to said system for improving
productivity and speed in sintering machine wherein the same is adapted such that the
retention time of heat holding of top layer preferably top most 200mm layer above 1100°C
is maintained by said reduction in air volume through bed.
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A still further aspect of the present invention directed to a system for improving productivity
and speed in sintering machine wherein the same is adapted such that high burn through
point temperature preferably > 350°C is achieved due to high air volume available in the
latter half of the sinter machine.
According to another important aspect of the present invention directed to a process for
improving productivity and speed in sintering machine comprising:
controlling the air volume distribution for controlling the air volume distribution along the
length of the sinter machine such that the air flow in initial length of the sinter machine is
restricted and also achieve extension of retention time of top layer due to reduction of air
volume thorough the bed.
A still further aspect of the present invention directed to said process for improving
productivity and speed in sintering machine comprising low volume of air distribution in the
initial half and high volume of air distribution in the latter half preferably the air flow control
regime is selective such that air flow in initial 40% of length of sinter machine is restricted
by 30% of damper of wind boxes of initial wind boxes.
Yet another aspect of the process for improving productivity and speed in sintering machine
according to the present invention, wherein the retention time of top layer preferably top
200mm layer above 1100°C is maintained by selective reduction in air volume through bed
and also high burn through point temperature preferably > 350°C is provided by way of
high air volume available in the later half of the sinter machine.
A still further aspect of the present invention directed to said process for improving
productivity and speed in sintering machine wherein to increase heat holding of the top
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layer of the sinter bed, air velocity sucked through sinter bed decreased by throttling the
wind boxes no. 1 to 7 by reducing damper opening as hereunder:

Wind Box
No. 1 2 3 4 5 6 7
%, opening 50 50 40 40 50 70 70
A still further aspect of the present invention directed to said process for improving
productivity and speed in sintering machine comprising reduction of air velocity to about 0.3
m/sec whereby the holding time of the top layer (about 80 mm from the surface) increased
to about 90 seconds, from 60 seconds before the throttling of the wind boxes.
The present invention and its objects and advantages are described in greater details with
reference to the accompanying figure.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURE
Figure 1: is the illustration of the flow chart for the air flow volume distribution and control
process, along the sintering bed length using the system according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING FIGURE
As already described, the present invention relates to a system for improving productivity
and speed of sinter machine and a process thereof adapted to control the air-volume
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distribution along the length of the sinter machine bed such that the air flow in initial length
of the sinter machine is restricted and also achieve extension of retention time of heat
holding of top layer due to reduction of air volume through the bed. Importantly, the
present system is capable to control the air volume distribution in the sinter machines
having large length exceeding 60 meters, wherein the air volume control in the initial 40%
of length is controlled by the operation of electrically controlled dampers mounted in the
Individual wind boxes of sinter machine such that the air volume saved in the initial length
of bed is utilized in the later part of sinter machine. Such control of air flow/volume along
sintering bed length advantageously increases the sintering speed in the later half of sinter
machine bed and thereby increases the sinter machine productivity. The present invention is
also directed to achieve high burn through point temperature of >350°C, by way of the high
air volume available in the later half of sintering machine, favoring also completion of
sintering process in the machine resulting in better quality of sinter, lower exhauster motor
power consumption due to high temperature of exhaust gas and also efficient cooling of
sinter. The system of the invention and the process adapted for air flow control using said
system favor increasing the specific productivity of sinter machine from the existing level of
1.18 to 1.33 t/m2/hr i.e. by about 12%.
Reference is now invited to the accompanying Figure 1, illustrating the flow diagram for
achieving the object of the improved productivity and sinter quality through enhanced
retention time of the top layer by carrying out the process of air flow distribution control
along the sintering bed length using the present system of the present invention comprising
electrically controlled dampers in the wind boxes for restricting the flow of air in the initial
40% length of the sinter bed by controlling the 30% of dampers installed in the
corresponding wind boxes in the initial portion of the sinter bed in the system. The
improvement in the sinter quality in terms of the Tumbler index and yield is achieved by
adopting a uniform heating pattern of the sinter bed wherein the heat holding time of the
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top layer of the sinter bed is extended and the heat holding time of the bottom layer of
sinter bed is reduced by selective throttle control of the wind box dampers and there by
controlling the air velocity sucked through the sinter bed. The process of the invention
directed to achieve higher yield and productivity is illustrated with the following example.
EXAMPLE:
In an embodiment of the present invention, the process for improving productivity and
increasing speed of sintering vertically by adopting desired air flow volume distribution
control in sintering machine wherein to increase heat holding of the top layer of the sinter
bed, air velocity sucked through sinter bed decreased by throttling the wind boxes no. 1 to
7 comprising the part of the system of the invention, by reducing damper opening as
illustrated hereunder in Table I.
Table:!

Wind Box
No. 1 2 3 4 5 6 7
%, opening
of dampers 50 50 40 40 50 70 70
The reduction of air velocity from 0.4 m/s to 0.3 m/s achieved through said operative
control of the dampers in the initial portion of the first half of the sinter bed length, the heat
holding time of the top layer, specified by a depth of 80mm to 200 mm from top surface of
sinter bed, has been increased to 90 seconds from the existing value of 60 seconds
conventionally obtained without the adoption of the throttling of the wind boxes. The
increased heat holding time of top elementary layer have resulted in increase in the yield
and productivity of the sinter machine. Also the heat holding time for the bottom layer of
sinter is reduced and thus achieving uniform heat pattern of the sinter bed. The results
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achieved by implementing the process using the system of the present invention are as
follows:
a. Improvement of yield of the top layer of sinter bed by up to 11%;
b. Burn through point temperature indicated by the waste gas temperature at the last
wind box of sinter machine increased from 320 to 380°C and consequently saving
power consumption of the exhauster motor;
c. Improvement in productivity of the sinter machine is increased from 1.18 to 1.33
t/m2/hr.
It is thus possible by way of this invention directed to a system for improving
productivity and speed of sinter machine and a process thereof adapted to control the
air-volume distribution along the length of the sinter machine bed such that the air flow
in initial length of the sinter machine is reduced and the air flow distribution in the latter
half of sinter bed is increased by selective throttling of the wind box dampers. The
process also achieve increased heat holding time of top layer due to reduction of air
velocity through the bed, improving the yield of top layer. The process of the invention
further ensures improved quality of sinter, reduced power consumption and higher yield
of sinter bed top layer, making the system and the process capable of wide application
in iron and steel industry.
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WE CLAIM:
1. A system for improving productivity and speed in sintering machine comprising:
means for air volume distribution control adapted for controlling the air volume
distribution along the length of the sinter machine such that the air flow in initial length
of the sinter machine is restricted and extension of retention time of top layer due to
reduction of air volume thorough the bed.
2. A system for improving productivity and speed in sintering machine as claimed in claim 1
wherein said means for air volume distribution control comprises damper controller
installed in the wind boxes of sinter machines.
3. A system for improving productivity and speed in sintering machine as claimed in anyone
of claims 1 or 2 wherein the air flow control regime is such that air flow in initial 40% of
length of sinter machine is restricted by 30% of damper of wind boxes of initial wind
boxes.
4. A system for improving productivity and speed in sintering machine as claimed in anyone
of claims 1 to 3 wherein the same is adapted such that the retention time of top layer
preferably top 200mm layer above 1100°C is maintained by said reduction in air volume
through bed.
5. A system for improving productivity and speed in sintering machine as claimed in anyone
of claims 1 to 4 wherein the same is adapted such that high burn through point
temperature preferably > 350°C is achieved due to high air volume available in the later
half of the sinter machine.
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6. A process for improving productivity and speed in sintering machine comprising:
controlling the air volume distribution for controlling the air volume distribution along the
length of the sinter machine such that the air flow in initial length of the sinter machine is
restricted and also achieve extension of retention time of top layer due to reduction of air
volume thorough the bed.
7. A process for improving productivity and speed in sintering machine as claimed in claim 6
comprising low volume of air distribution in the initial half and high volume of air
distribution in the latter half preferably the air flow control regime is selective such that air
flow in initial 40% of length of sinter machine is restricted by 30% of damper of wind
boxes of initial wind boxes.
8. A process for improving productivity and speed in sintering machine as claimed in anyone
of claims 6 to 7 wherein the retention time of top layer preferably top 200mm layer
above 1100°C is maintained by selective reduction in air volume through bed and also
high burn through point temperature preferably > 350°C is provided by way of high air
volume available in the later half of the sinter machine.
9. A process for improving productivity and speed in sintering machine as claimed in anyone
of claims 6 to 8 wherein to increase heat holding of the top layer of the sinter bed, air
velocity sucked through sinter bed decreased by throttling the wind boxes no. 1 to 7 by
reducing damper opening as hereunder:

Wind Box
No. 1 2 3 4 5 6 7
%, opening 50 50 40 40 50 70 70
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10. A process for improving productivity and speed in sintering machine as claimed in
anyone of claims 6 to 9 comprising reduction of air velocity to about 0.3 m/sec whereby
the holding time of the top layer (about 80 mm from the surface) increased to about 90
sec before the throttling of the wind boxes.
11. A system for improving productivity and speed in sintering machine and a process for
such improved productivity and speed of sintering substantially as herein described and
illustrated with reference to the accompanying examples.


Dated this 27th day of February, 2008

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A system for improving productivity and speed of sinter machine and a process thereof
adapted to control the air-volume distribution along the length of the sinter machine bed
such that the air flow in initial length of the sinter machine is restricted and also achieve
extension of retention time of heat holding of top layer above 1100°C. The system is
capable to control the air volume distribution by the operation of electrically controlled
dampers mounted in the individual wind boxes of sinter machine such that the air volume
saved in the initial length of bed is utilized in the later part of sinter machine. Such control
advantageously increases the sintering speed and sinter machine productivity. The system
of the invention and its process adapted for air flow control favor increasing the specific
productivity of sinter machine from the existing level of 1.18 to 1.33 t/m2/hr i.e. by about
12% associated with an improvement of Yield of 11% of the top layer of sinter bed and
saving in exhauster motor power consumption .