Claims:WE CLAIM:
1. A system (100) for online monitoring and estimation of pulverized coal particle size distribution, the system (100) comprising:
a coal sample preparation mechanism (300) having:
an isokinetic sampler (120) configured to receive pulverized coal,
a motorized dispensing funnel (130) coupled to the isokinetic sampler (120), the motorized dispensing funnel (130) being configured to dispense a predetermined amount of the pulverized coal,
a conveyor belt (310) coupled to the motorized dispensing funnel (130), the conveyor belt (310) being configured to receive the predetermined amount of the pulverized coal; and
an image capturing mechanism (200) coupled to the coal sample preparation mechanism (300), the image capturing mechanism (200) having:
a microscopic camera (210) configured for imaging the predetermined amount of the pulverized coal dispensed on the conveyor belt (310),
a computing device (270) coupled to the microscopic camera (210), the computing device (270) being configured to acquire a coal particle image (290) through the microscopic camera (210), wherein the computing device (270) includes an image processing application (600) being configured for providing the pulverized coal particle size distribution based on processing and analysis of the coal particle image (290).

2. The system (100) as claimed in claim 1, wherein the conveyor belt (310) includes a plurality of microscopic slides (320), the microscopic slides (320) being fixed on the conveyor belt (310) for receiving the predetermined amount of pulverized coal.
3. The system (100) as claimed in claim 1, wherein the conveyor belt (310) is controlled by a stepper motor.
4. The system (100) as claimed in claim 1, wherein the microscopic camera (210) includes an object lens (220)
5. The system (100) as claimed in claim 1, wherein the microscopic camera (210) is provided with a plurality of light sources (230).
6. The system (100) as claimed in claim 1, wherein the motorized dispensing funnel (130) is provided with a sliding mechanism (150), wherein the sliding mechanism is configured for moving and evacuating the motorized dispensing funnel (130) relative to the conveyor belt (310).
7. The system (100) as claimed in claim 1, wherein the coal sample preparation mechanism (300) further includes:
a buffing wheel (410) provided proximally to the conveyor belt (310),
a cleaning material (430) wrapped around the buffing wheel (410), and
an engagement mechanism (440) provided with the buffing wheel (410), wherein the engagement mechanism (440) moves the buffing wheel (410) relative to the conveyor belt (310) for cleaning the slides (320) by the cleaning material (430).
8. A method for online monitoring and estimation of pulverized coal particle size distribution, the method comprising:
imaging a sample of pulverized coal by an imaging system block(500), the imaging system Block (500) having:
a sample collection block (510) for sampling the pulverized coal using an isokinetic sampler (120), wherein the isokinetic sampler (120) feeds the pulverized coal to a motorized dispensing funnel (130),
a slide preparation block (520) for dispensing a predetermined amount of the pulverized coal from the motorized dispensing funnel (130) on to a plurality of microscopic slides (320) disposed on a conveyor belt (310),
a slide positioning block (530) for positioning the microscopic slides (320) under a microscopic camera (210) by moving the conveyor belt (310) by a stepper motor,
an image capturing block (540) for acquiring, by the microscopic camera (210), a coal particle image (290) of the pulverized coal disposed on the slides (320);
processing the coal particle image (290) by an image processing block (600), the image processing block (600) having:
a segmenting block (610) for performing first level image segmentation operation on the coal particle image (290)for separating particles from the background,
an image enhancement block (620) for improving quality of the coal particle image (290),
an edge detection block (630) for performing an edge detection operation on the coal particle image (290)for isolating coal particles and computing the area of each particle,
a distribution estimation block (640) for converting the area of each particle in to an equivalent diameter of particles sizes and further sorting as per particle diameters; and
visualizing estimated coal particle size distribution by a distribution visualization block (800) based on the diameter of particles.

9. The method as claimed in claim 8 further comprising:
cleaning of the slides (320) by a cleaning block (700), the cleaning block (700) having:
a positioning block (710) for moving the conveyor belt (310) having the microscopic slides (320) towards a rotating buffing wheel (410),
a slide cleaning block (720) wherein the buffing wheel (410) cleans the slides (320), and
a funnel cleaning block (730) for moving and evacuating the motorized dispensing funnel (130).
10. The method as claimed in claim 9, wherein the motorized dispensing funnel is moved and evacuated by a sliding mechanism (150).
, Description:A method and system for online monitoring and estimation of pulverized coal particle size distribution
FIELD OF INVENTION
[001] The present disclosure relates to particle size distribution in power plants, more particularly, the present disclosure relates to a system and an associated method for continuous online monitoring during the operation and estimation of pulverized coal particle size distribution before the coal particles enter into furnace area to get burned and release heat energy.

BACKGROUND OF THE INVENTION

[002] Efficiency and performance of power plants running on pulverized coal depends upon combustion efficiency of the coal and amount and composition of the pollutants generated from combustion of the pulverized coal, which in turn depends upon desired amount and of a desired particle sizes of the pulverized coal. Hot pressurized air is introduced to dry and transport the pulverized coal by fluidizing it so that it can be delivered to the burners for combustion.

[003] It is experimentally noticed that certain distribution of the coal particles has efficient combustion for given design, whereas deviation from the distribution suggested, leads to inefficient combustion. The inefficient combustion leads to higher pollutants and higher cost of energy generation. In case the distribution has small sized particles, then these small particles escape without fully burning and become part of fly-ash. In the other case, i.e. if the particles are large in size, then these particles fall without fully burning due to gravitational pull, and become part of bottom-ash.

[004] Therefore, maintaining the range with appropriate distribution between suggested small sized coal particles to large sized coal particles is an important requirement for efficient combustion to happen in the furnace area. Various methods and techniques have been proposed to cater to the aforementioned situation, however, they lack efficiency and accuracy.

PRIOR ART:

[005] Now, reference may be made to the following prior arts discussing state of the art techniques.

[006] EP0435570A1 discusses a method for measuring the size and distribution of particles in a particulate composition comprises scanning an image or a thin sample of the particulate composition, obtaining chord data of the particles along a plurality of scan lines, and converting chord data to particle size.

[007] US7177487B2 provides method related to determine particle size using image analysis. The method is particularly suitable for small particles such as those that are less than 1 um in size by scanning electron photomicrographs.

[008] US8655048B2 discusses a method and apparatus for measuring size distribution of granular matter, which are capable of compensating for the random orientation of the granules constituting such matter using computer image processing. The image data is segmented to reveal regions associated with distinct granules, and values of the size-related parameter for the revealed regions are estimated.

[009] Embodiments of the invention disclosed in US2007/0229823A1 relates to determining the number concentration and size distribution of particles using dark-field microscopy. These embodiments are especially useful for the simultaneous determination of particle number concentration and size distribution of particles with dimensions below 4 microns.

[0010] US2010/0169038A1 provides processes employing algorithms and methods for calculating particle size distribution. In particular, the present invention provides processes employing algorithms and methods for calculating particle size distribution of different particle shapes from chord length distributions.

[0011] US2010/0248046A1 discusses a method of creating a particle size distribution model, a method of predicting degradation of a fuel cell catalyst, using the method of creating the particle size distribution model, and a method of controlling a fuel cell, using the method of predicting degradation of the fuel cell catalyst. If the particle size distribution of the platinum catalyst obtained by measurement/ experiment as described above is used for predicting degradation of the fuel cell catalyst, simulation results cannot be obtained within a practical calculation time.

[0012] The invention disclosed in US2013/0156293A1, relates to multi-crystalline solar wafers and, more specifically, to methods and systems for grain size evaluation of multi-crystalline solar wafers. The method includes illuminating a multi-crystalline Wafer according to a plurality of lighting parameters, capturing a plurality of images of the multi-crystalline wafer, stacking and projecting the plurality of images to generate a composite image, analyzing the composite image to identify one or more grains of the multi-crystalline Wafer, and generating a report based on the analysis of the composite image.

[0013] US2014/0320639A1 provides a system for estimating size distribution and concentration of aerosols in an atmospheric region includes a digital camera, a sunlight attenuation filter, and a processor. The filter is aligned between the sun and the camera’s aperture. Image processing is performed on an image captured when the filter and the sky are in focus of the camera.

OBJECTS OF THE INVENTION

[0014] The objective of the present invention is to develop a system and method for online monitoring and estimating pulverized coal particle size distribution byutilizing a mechanism to collect a coal sample, prepare the sample for imaging, analyzing the image, and estimating the pulverized coal particle size distribution.

SUMMARY OF THE INVENTION

[0015] A system (100) for online monitoring and estimation of pulverized coal particle size distribution is disclosed. The system (100) includes a coal sample preparation mechanism (300) having an isokinetic sampler (120) configured to receive pulverized coal, a motorized dispensing funnel (130) coupled to the isokinetic sampler (120), the motorized dispensing funnel (130) being configured to dispense a predetermined amount of the pulverized coal, a conveyor belt (310) coupled to the motorized dispensing funnel (130), the conveyor belt (310) being configured to receive the predetermined amount of the pulverized coal; and an image capturing mechanism (200) coupled to the coal sample preparation mechanism (300), the image capturing mechanism (200) having a microscopic camera (210) configured for imaging the predetermined amount of the pulverized coal dispensed on the conveyor belt (310),a computing device (270) coupled to the microscopic camera (210), the computing device (270) being configured to acquire a coal particle image (290) through the microscopic camera (210), wherein the computing device (270) includes an image processing application (600) being configured for providing the pulverized coal particle size distribution based on processing and analysis of the coal particle image (290).

[0016] A method for online monitoring and estimation of pulverized coal particle size distribution is disclosed. The method including imaging a sample of pulverized coal by an imaging system block(500).The imaging system Block (500) having a sample collection block (510) for sampling the pulverized coal using an isokinetic sampler (120), wherein the isokinetic sampler (120) feeds the pulverized coal to a motorized dispensing funnel (130),a slide preparation block (520) for dispensing a predetermined amount of the pulverized coal from the motorized dispensing funnel (130) on to a plurality of microscopic slides (320) fixed on a conveyor belt (310),a slide positioning block (530) for positioning the microscopic slides (320) under a microscopic camera (210) by moving the conveyor belt (310),an image acquiring block (540) for acquiring, by the microscopic camera (210), a coal particle image (290) of the pulverized coal disposed on the slides (320);processing the coal particle image (290) by an image processing block (600).The image processing block (600) having a segmenting block (610) for performing first level image segmentation operation to separate particles from the background, an image enhancement block (620) for improving quality of the coal particle image (290),an edge detection block (630) for performing an edge detection operation to isolate coal particles and compute the area of each particle, a distribution estimation block (640) for converting the area of each particle in to equivalent diameter of particles sizes and further sorting as per particle diameters; and visualizing estimated coal particle size distribution by a distribution visualization block (800) based on the diameter of particles.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0017] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of the exemplary embodiments and wherein:
Figure 1shows: A block diagram of a system (100) for estimating pulverized coal particle size distribution.
Figure 2 shows: The system (100) including a coal sample preparation mechanism (300), and an image capturing mechanism (200).
Figure 3 shows: A block diagram explaining the sequence of operations involved in the system (100).
Figure 4 shows: (a) Coal particles Image as captured by embodiments shown in Fig. 2, (b) Preprocessed Image of (a), (c) Processed Image for estimating coal particles sizes and their distribution.
Figure 5 shows: A curve showing distribution of particle sizes with number of particles.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

[0018] The present invention, now be described more specifically with reference to the following specification.

[0019] Fig. 1, shows schematic diagram of an overall system (100) with its embodiments including, but not limited to a Coal sample preparation mechanism (300) and an image capturing mechanism (200) as described with reference to Fig.2., wherein an image (290) is captured and is processed and analyzed by a digital image processing application (600) for achieving a visualization of estimated coal particle size distribution (800) as shown in Fig. 5.

[0020] Fig. 2, shows a system (100) for monitoring and estimating pulverized coal size distribution. The system (100) includes a coal sample preparation mechanism (300), and an image capturing mechanism (200) coupled to the coal sample preparation mechanism (300). The coal sample preparation mechanism (300) includes an isokinetic sampler (120) configured to receive pulverized coal from a pulverizer exit, the pulverized coal being channelized towards a furnace (110). The isokinetic sampler (120) collects the pulverized coal and feeds it to a motorized dispensing funnel (130).

[0021] The motorized dispensing funnel (130) includes a receiving end configured to receive the pulverized coal from the isokinetic sampler (120), and a dispensing end configured to dispense a predetermined amount of pulverized coal. The dispensing end of the funnel (130) is provided with a rotating motorized screw (140). The motorized screw (140) is configured to rotate in a direction (160) for dispensing the predetermined amount of pulverized coal.

[0022] The motorized dispensing funnel (130) is coupled to a stepper motor controlled conveyor belt (310) holding microscopic slides (320), wherein the funnel (130) dispenses the predetermined amount of pulverized coal on to the microscopic slides (320) through the motorized screw (140) to form spread.

[0023] With the help of the stepper motor of the conveyor belt (310), pulleys (330, 340) provided with the conveyor belt (310) are rotated in clockwise (350, 360) direction to move the plurality of microscopic slides (320) on the conveyor belt (310) towards the image capturing mechanism (200).

[0024] The image capturing mechanism (200) includes a microscopic camera (210) having an object lens (220). The mechanism (200) further includes a plurality of light sources (230) proximal to the camera (210).Light beams (240) from the light sources (230) are focused (260) onto the slides (320), and the microscopic camera (210) having a view angle (250) is activated through a computing device (270) to acquire a coal particle image (290) as shown in Fig. 4. The image (290)is stored in a storage media (280) for further processing and analysis. The stored image (290) is then processed by an image processing application (600) shown in Fig. 3.

[0025] Further, after the image capturing mechanism (200) takes place, the conveyer belt (310) moves along with microscopic slides (320) towards a rotating buffing wheel (410). The buffing wheel (410) is configured for a cleaning mechanism of the slides (320) disposed on the conveyor belt (310). The buffing wheel (410), wrapped with cleaning material (430), rotates in an anti-clockwise direction (420) and is brought near to the conveyor belt (310) using an engaging mechanism (440). The buffing wheel (410) cleans the plurality of slides (320) one after other as they come to its access and makes them ready for next coal sample to be spread onto them.

[0026] Each one of the coal samples collected in the motorized dispensing funnel (130), is used for preparing plurality of microscope slides (320) one after other by operating the conveyor belt (310) at an appropriate speed. After preparing predetermined “N” number of slides (320), the motorized dispensing funnel (130) is moved and evacuated and kept ready to accept next pulverized coal sample from pulverizer. In an embodiment, the motorized dispensing funnel (130) is moved and evacuated by a sliding mechanism (150).

[0027] The block diagram shown in Fig. 3, explains the sequence of various operations logically involved in estimating the coal particles size distribution. Fig.3 divides overall operations into four main operational blocks viz. Imaging System Block (500), Image Processing Application Block (600), Cleaning Block (700), Distribution Visualization Block (800). Further, these four operational blocks subdivided to explain operations in detail.

[0028] The Imaging System Block (500) includes a Sample Collection Block (510) wherein the pulverized coal is sampled using isokinetic sampler (120) at the pulverizer exit, where a stoichiometric mix of the pulverized coal and air is being channeled towards the furnace (110). Collected pulverized coal is then be fed into the motorized dispensing funnel (130).

[0029] The Imaging System Block (500) further includes a Slide Preparation Block (520), wherein the motorized dispensing funnel (130) dispenses a predetermined amount of pulverized coal onto the microscopic slides (320)disposed on to the conveyor belt (310), by rotating the motorized screw (140) in the direction (160).

[0030] The Imaging System Block (500) further includes a Slide Positioning Block (530) wherein the conveyor belt (310) moves along with prepared microscopic slides (320) to position them under the microscopic camera (210), where the light sources (230) focuses onto the coal particles provided on to the slides (320).

[0031] The Imaging System Block (500) further includes an Image capturing Block (540) wherein the camera (210) captures the image (290) of the coal particles spread on the microscopic slides (320).

[0032] The Imaging System Block (500) further includes an Iterative Block (570) wherein, operations (520, 530, 540) repeats for predetermined “N” number of times by following instructions (550) and (560) for the same coal sample collected in the motorized dispensing funnel (130).

[0033] Fig. 3 further illustrates an Image Processing Application Block (600).The captured image (290) is then supplied to the image processing application block (600) to perform first level image segmentation operation by a segmenting block (610) to separate particles from the background and generate segmented image (292) as shown in Fig. 4.

[0034] In Image enhancement block (620), the image quality is improved by applying one or more of operations including, but not limited to: Contrast enhancement, Brightness improvement, sharpness improvement, and a set of image transformations that are performed in an appropriate sequence.

[0035] In Edge detection Block (630), edge detection operation is performed to isolate coal particles and generate image with identified particles’ boundaries (294) as shown in Fig. 4andthen compute the area of each particle.

[0036] In Distribution Estimation Block (640), all the particles areas are estimated based on the identified particles’ boundaries (294), then the estimated areas are converted into equivalent diameter of particles sizes and then the image processing application (600) sorts as per particle diameters to estimate distribution. Particles with same area are grouped and counted. In this manner, particles diameter from considered minimum to maximum with their frequency counts are plotted and visualized as (800) in Fig.5.

[0037] Fig. 3 further illustrates a Cleaning Block (700) coupled with the Imaging System Block (500) through (590). The cleaning block (700) includes a positioning block (710), wherein the conveyer belt (310) moves along with microscopic slides (320) towards the cleaning mechanism, i.e. rotating buffing wheel (410).

[0038] In Slide Cleaning Block (720), the buffing wheel (410) cleans the slides (320) and makes them ready for next coal sample spread onto them.

[0039] In Funnel Cleaning Block (730), the motorized dispensing funnel (130) is moved away from the conveyor belt (310) with sliding mechanism (150) and evacuated to keep ready to accept next pulverized coal sample.

[0040] Fig. 4, depicts image at various stages including acquired image (290) as it is, segmented image (292) using image processing application (600) and finally, image with identified particles’ boundaries (294).

[0041] Fig. 5, visualizes the coal particles size distribution (800) indicating, x-axis as diameter of the particles and y-axis as number of particles corresponding to the diameters.

[0042] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims.