FIELD OF THE INVENTION
The present invention generally relates to a camera based Tuyere Monitoring
System for blast furnace. More particularly, the invention relates to a real time
method of automatic inspection of tuyers in blast furnace to reduce downtime of
the furnace.
BACKGROUND OF THE INVENTION
With the advent of pulverized coal injection (PCI) in blast furnaces, it has
become/very important and critical to be able to detect problems in the PCI
systems at the tuyeres. As the PCI rates increase, furnace downtime resulting
from tuyere, blowpipe and upper assembly failure also increases, often resulting
in furnace breakouts and failure of furnace auxiliary equipment.
The PCI method is based on the simple concept of primary air (termed the
"conveying gas") carrying pulverized coal which injected through a lance to the
tuyere (mid-bottom inlet of a blast furnace), then mixed with secondary hot air
(termed the "blast") supplied through a blowpipe in the tuyere and then piped to
a furnace to create a balloon-like cavity called a "raceway", which then
propagates coal and coke combustion and melts the solid iron ore, releasing
molten iron. The most remarkable aspect of this method is that it allows for
cheaper coal to be consumed in the system, replace expensive coke, thereby
remarkably cutting down on costs. Because of the severe environment inside the
furnace, (>200K), visual observation of raceway shape and size is impossible;
therefore remotely measuring sensors are used to investigate the chemical and
physical reactions inside the furnace. Better understanding of the raceway and
PCI method can optimize the performance of a blast furnace and reduce costs.
With the advent of pulverized coal injection (PCI) in blast furnaces, it has
become very important and critical to be able to detect problems in the PCI
systems at the tuyeres. As the PCI rates increase, furnace downtime resulting
from tuyere, blowpipe and upper assembly failure also increases, often resulting
in furnace breakouts and failure of furnace auxiliary equipment
It is known to use a photosensitive resistor to measure the absence of light from
a tuyere through which finely divided coal is being injected into a blast furnace,
thereby indicating blockage of the tuyere and enabling coal flow to that tuyere to
be shut off.
CN 10122040 to Shicai Yang et al discloses a real-time online alarm system for
blast furnace tuyere, which belongs to the technical field of blast furnace
monitoring. The invention consists of real-time online information collection,
treatment, alarm part, and an electric circuit of all functions of the invention. The
system has the following advantages that:
a. The alarm system can monitor the real-time online operation conditions of
each blast furnace tuyere, display the real-time image of coal-spraying
combustion for each tuyere, and send out sound and light alarm timely for
the abnormal coal-spraying tuyere, so the monitoring content is complete
and practical;
b. By adopting industrial television technology as the real-time online
monitoring technology for coal-spraying combustion of the blast furnace
tuyere, the display is visual, eye catching, and easy to monitor;
c. By using the alarm system, the operator can maintain the abnormal coal-
spraying tuyeres timely, so the alarm system is easy to remove faults and
guarantees safe production of the blast furnace;
d. By using the monitoring and alarm system for coal-spraying combustion of
the blast furnace tuyere, the invention can not only improve the
combustion efficiency and the heat value of coal but also improve the
output and quality of the pig iron. The novel real-time online alarm system
of the blast furnace tuyere is good for being adopted and generalized in
the steel making and blast furnace producing industry.
JP2002309307 to Matsuzaki Shinroku et al proposes a technique with
which a temperature variation from a tuyere to a raceway can precisely
and continuously be measured in a non-contacting manner and the state
near the tuyere can be estimated. This invention provides a system
comprising an image pickup unit with which the thermographic picture of
the burning field in the raceway is picked up at two different wave lengths
through an observation port at the tuyere in the blast furnace; and a
digital conversion device with which a picture signal output from the
above image pickup unit is converted into a digital figure. Then, a
histogram is drawn by obtaining the temperature from two-color
luminance in the pixels of the digital figure converted with the digital
converting device to detect the temperature in the furnace with the
histogram shape.
KR 20010063896 to Han Gi Won et al teaches a remote monitoring
apparatus for remote monitoring a tuyere of a blast furnace which
remotely inspects conditions inside the blast furnace so as to prevent that
an operator of the blast furnace is exposed to dangers that are still in
existence surrounding the blast furnace since the operator directly checks
the conditions inside the blast furnace with the naked eye. According to
the invention, the remote monitoring apparatus monitors the conditions of
pyrites falling and pulverized coal combustion inside a blast furnace (1)
through an observatory window of a tuyere in the blast furnace. The
apparatus comprises a circular rail (10) installed along the tuyere in the
circumferential direction of the blast furnace; an automatic running
system transferable installed along the circular rail; a transferable camera
(13) interlocked to the transfer of the automatic running system; a cooling
system for cooling the camera; and an operation part storing information
on the conditions inside the blast furnace transmitted from the camera.
JP 3122207 to Hanazaki et al teaches an instrument to efficiently execute
operation of a melting furnace by inserting plural pieces of image guides
providing camera near tuyeres in a cylindrical melting furnace and
grasping charging condition of materials from an original image obtained
through the camera. According to this invention, a plurality of detecting
parts are inserted at upper and lower two steps near the tuyeres in the
cylindrical melting furnace, and the detecting part is constituted with the
image guide and the camera providing protecting lance connecting with
this. The raw images in the furnace obtained through the camera are
outputted to an operating processor and monitor in order at the
prescribed timing with an image signal switching unit and selectively
controlled while switching. The operating processor decides the kind of
the charged material in the furnace by executing the image processing to
the original image obtained from each camera and circumferential
distribution and velocity at which passing the detecting part for the
charged material in the furnace are calculated and outputted to a furnace
control device and control of blowing rate of fuel gas, from the tuyere and
iron tapping quantity is executed.
According to JP 5256705 to Sekiya Masahiro et al a radiation temperature
camera is set in a tuyere of a blast furnace. The temperature distribution
inside the tuyere is image processed. The temperature in the tuyere is
divided into a plurality of sections from the temperature data. The burning
characteristics (the area ratio per temperature, the area ratio of black part
and the dropping count of raw ore) of carbon black are obtained from the
relationship of the data and the burning degree of carbon black in
combination with the operation of a function or a rule.
CN 201626968 to Zhengkai et al describes a blast furnace tuyere
observing device with a side-view optical splitter, comprising a barrel-
shaped connecting sleeve, a video camera and an optical splitter, wherein
the barrel-shaped connecting sleeve is provided with a near end and a far
end along the longitudinal axis thereof, and the near end is matched with
a tuyere peephole of a blast furnace; the video camera is arranged in the
far end; and the optical splitter comprises an optical splitting lens which is
arranged between the near end and the far end and is obliquely crossed
with the longitudinal axis so that a part of light rays can pass through the
optical splitting lens and enter the video camera to form a first light path,
and the rest part of the light rays can be reflected to the side wall of the
barrel-shaped connecting sleeve by the optical splitter to form a second
light path. By using the observing device, operators not only can remotely
observe the internal conditions of the blast furnace through the video
camera, but also simultaneously directly observe the internal conditions of
the blast furnace in site through naked eyes. Therefore, the observing
device not only reduces the labor intensity of the operators during
pooling, but also greatly improves working efficiency so that the operators
can treat the abnormal conditions of tuyeres and coal powder injection in
time.
JP 2011021835 to Kotani Kazuhiko et al teaches a waste melting furnace
confirming a closing state of tuyeres in real time, including a method of
operating the waste melting furnace. According to this invention, waste is
charged in the furnace from an upper part , and an oxygen source is
supplied from the tuyeres at a plurality of stages arranged in a furnace
lower part. Ash in the waste molten through reaction heat and unburned
objects are discharged from a discharge hole in a furnace bottom part.
Thermometers are arranged in all of oxygen source gas supply piping for
individually supplying oxygen source gas to the respective tuyeres and a
transmitter for transmitting temperature data measured by the respective
thermometers by radio is installed. The temperature data transmitted by
the transmitter is received in an operation chamber and displayed by a
temperature display device installed in the operation chamber, so as to
confirm the closing state of tuyeres, based on the displayed temperature
data.
The non-patent literature entitiled "BF tuyere CCD imaging monitoring
system" published on 24.01.2009, which allows continuous monitoring of
the tuyeres from the operating room, so that blast furnace operators are
enabled to observe at any time tuyere brightness, the level of activity, PCI
status, tuyere defects, and improve the performance of the monitoring
accurately. The use of digital image processing technology on the raceway
flame image processed by the roundabout of the temperature distribution
in the region. The temperature of the digital image analysis results with
the measured results when compared exhibited an error of 3 percent or
less.
The non-patent literature by quyang, q et al entitled "a" teaches that
radiative imaging of pulverized coal combustion in the blast furnace
raceway plays an increasingly important role in working state diagnosis
and monitoring in real time. This paper presents a method for calculating
the radiation of three-dimensional (3D) combustion flames based on the
Monte Carlo method and charge coupled device (CCD) imaging. The
relationship between two-dimensional radiative image and 3D radiant
energy in the blast furnace raceway was studied by numerical simulation
of the combustion process in this study. The radiative images obtained
from the blow pipe peephole of a blast furnace tuyere not only present
the energy distribution on the CCD camera target plane but also examine
3D temperature distribution in the blast furnace. The numeral
temperature field matching the actual combustion can be obtained by a
proposed numeric image processing technique.
The major disadvantages of the prior art, is that the condition of tuyeres
near to a plugged or blocked tuyere is indicative of possible failure of
'those nearby tuyeres. It is recognized that such a condition can be caused
Iby several abnormal conditions, such as plugged injection lance, sensor
failure, coal in the bustle pipe of the furnace feeding air to the tuyeres
etc. In the invention proposed here, such problems can be averted,
thereby proving to be a robust and stable system for the monitoring of
tuyeres.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a real time method of
automatic inspection of tuyers in blast furnace to reduce downtime of the
furnace, which eliminates the disadvantages of prior art.
Another object of the invention is to propose a real time method of automatic
inspection of tuyers in blast furnace to reduce downtime of the furnace, which is
enabled to convert monochrome image acquired in real time to thermal profile.
A still ahother object of the invention, a real time method of automatic inspection
of tuyers in blast furnace to reduce downtime of the furnace, which allows
monitoring of heat zones including the tuyere temperature based on the thermal
profile.
Yet another object of the invention, a real time method of automatic inspection
of tuyers in blast furnace to reduce downtime of the furnace, which is capable to
determine the blockage due to increase of PCI rates at the tuyeres in terms of
intensity image percent of the tuyeres.
A further object of the invention, a real time method of automatic inspection of
tuyers in blast furnace to reduce downtime of the furnace, which is capable to
automatically generate an alarm when the blockage exceeds a threshold value.
A still further object of the invention, a real time method of automatic inspection
of tuyers in blast furnace to reduce downtime of the furnace, which is enabled to
transmit the real time processed data in respect of tuyere operations into the
control room to arrest PCI-increase.
SUMMARY OF THE INVENTION
Accordingly, there is provided a real time method of automatic inspection of
tuyers in blast furnace to reduce downtime of the furnace, the method
comprising the steps of : on-line acquiring of digital operational data of the
* tuyeres including associated blast furnace data by a plurality of CCD cameras
disposed as an array and acting as visual sensors to monitor each tuyere, the
cameras having Gig E connectivity and set-up with a frame jot of at least 35
frames/second;
connecting a powered over Ethernet (POE) switch at a first end the cameras and
connecting a second end of the POE Switch to a first fibre optic media converter
such .that the captured digital data in the form of image is transmitted from the
cameras to the first optic media converter;
providing a second fibre optic media converter in the control room to receive
data from the first fibre optic media converter via fibre optic cables;
and providing an image processing unit at the control room for receiving the
images from the second fibre optic media converter to determine the blockages
in the tuyeres including thermal profile of the tuyeres with temperature and heat
zones; and
a display device operably connected to the image processing unit to display the
processed images including means for raising audio alarm when the processed
parameters exceed threshold values.
According to the invention, CCD cameras are adapted which act as visual sensors
for monitoring of tuyeres. Each tuyere is monitored by one camera and the
images from all the tuyeres are simultaneously displayed in the monitor at the
control room using an image processing technique. Moreover, using advanced
image processing techniques, each of the monitors shows the thermal profile of
the tuyeres indicating the temperatures and heat-zones. Most importantly, the
blockage of the tuyere is displayed as a percentage based on the intensity of the
images of the tuyeres. Further, blockage over and above a threshold value
generates an alarm to the operator to stop the PCI and take immediate action.
Further, the present invention allows for the setting of a single "trip point"
representing a blocked tuyere enabling the subsequent stopping of coal injection
to that particular tuyere.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows a basic block diagram of the Tuyere monitoring system.
Figure 2 shows a detailed block diagram of the inventive Tuyere Monitoring
System.
DETAIL DESCRIPTION OF THE INVENTION
As shown in figure 2, the tuyers are monitored by implementing the steps as
under: ,
• First, the images are captured digitally using a IP base camera,
• The captured images are sent to processing units with the help of fiber
optic cables,
• The processing unit receives the images, and then checks if there are any
blockages in the tuyeres and provides a numerical value for the blockage
if any.
• Then, the image is processed to obtain the thermal profile and this
provides the various heat zones of the tuyeres for understanding of the
operators.
• The image are then stored in data storage media using which images for
any historical time can be retrieved.
As shown in figure 1, each tuyere is monitored using a camera and then the
camera is linked to an image processing unit through fiber optic cables. The
image processing unit then processes the images obtained and displays the
results in a displaying unit for the operator.
As shown in figure 2, the cameras are digital in nature with a CCD array for
image acquisition with GigE connectively and the frame rate is set at 35
frames per second for each camera. The cameras are powered over Et hernet
(POE) and all the cameras from the tuyeres are connected to a POE switch
which in turn is connected to a first fiber optic media converter. The images
are transmitted to the control room using fiber optic cables capable to
transmit data to longer distances.
At the receiver's end in the control room, a second fiber optic media
converter unit is placed and the data is received and then connected to the
image processing unit, which provides the blockage in the tuyeres including
the thermal profiles of the tuyeres with temperature and heat zones.
Thus, this real-time application of image processing to Blast furnace proves to
be very robust in terms of being independent and enabled to generate auto-
alarms thereby providing greater control and reducing the downtimes of the
blast furnace. Image processing algorithms are also very robust thereby
making the complete system full proof.
The major advantages of this system are:
The system provides a robust visual inspection system to monitor the
tuyeres independently and continuously which generates auto-alarms
when there is a blockage.
• Also, the operation of a blast furnace can be controlled with
information from the thermal profiles of the tuyere.
• Since, the sensors of each tuyere are independent; any failure in the
sensor can be dealt with independently without affecting the overall
system.
WE CLAIM :
1. A real time method of automatic inspection of tuyers in blast furnace to
reduce downtime of the furnace, the method comprising the steps of:
on-line acquiring of digital operational data of the tuyeres including
associated blast furnace data by a plurality of CCD cameras disposed as
an array and acting as visual sensors to monitor each tuyere, the cameras
having Gig E connectivity and set-up with a frame jot of at least 35
frames/second;
- connecting a powered over Ethernet (POE) switch at a first end the
cameras and connecting a second end of the POE Switch to a first fibre
optic media converter such that the captured digital data in the form of
image is transmitted from the cameras to the first optic media converter:
providing a second fibre optic media converter in the control room to
receive data from the first fibre optic media converter via fibre optic
cables;
and providing an image processing unit at the control room for receiving
the images from the second fibre optic media converter to determine the
blockages in the tuyeres including thermal profile of the tuyeres with
temperature and heat zones; and
a display device operably connected to the image processing unit to
display the processed images including means for raising audio alarm
-when the processed parameters exceed threshold values.

The invention relates to a real time method of automatic inspection of tuyers in
blast furnace to reduce downtime of the furnace, the method comprising the
steps of : on-line acquiring of digital operational data of the tuyeres including
associated blast furnace data by a plurality of CCD cameras disposed as an array
and acting as visual sensors to monitor each tuyere, the cameras having Gig E
connectivity and set-up with a frame jot of at least 35 frames/second;
connecting a powered over Ethernet (POE) switch at a first end the cameras and
connecting a second end of the POE Switch to a first fibre optic media converter
such that the captured digital data in the form of image is transmitted from the
cameras to the first optic media converter; providing a second fibre optic media
converter in the control room to receive data from the first fibre optic media
converter via fibre optic cables; and providing an image processing unit at the
control room for receiving the images from the second fibre optic media
converter to determine the blockages in the tuyeres including thermal profile of
the tuyeres with temperature and heat zones; and a display device operably
connected to the image processing unit to display the processed images
including means for raising audio alarm when the processed parameters exceed
threshold values.