Methods of rotary kiln thermal monitoring and cooling

Abstract

A system for monitoring brick in a rotary kiln includes an infrared sensor and a computing system configured to: obtain a digital model of a brick layer of a rotary kiln having a plurality of bricks, wherein the digital model of the brick layer is based on a measured brick thickness correlated with a measured infrared temperature for each brick; obtain infrared data of the rotary kiln with the at least one infrared imaging sensor; determine the measured infrared temperature for each brick; determine a brick thickness of a first brick in the brick layer of the rotary kiln based on the measured infrared temperature assigned to the first brick with the digital model of the brick layer; and provide the brick thickness of the first brick in a brick thickness report.

1 . A method for detecting a hotspot on a rotary kiln, comprising:
 obtaining at least one baseline infrared image of a fixed field of view of the rotary kiln;   analyzing all pixels in the fixed field of view of the at least one baseline infrared image for each pixel temperature;   determining an acceptable temperature range for each pixel in the fixed field of view;   obtaining at least one subsequent infrared image of the fixed field of view of the rotary kiln;   determining a temperature for all pixels in the fixed field of view of the at least one subsequent infrared image;   determining whether the temperature for each pixel in the at least one subsequent infrared image is within the acceptable temperature range, when the temperature is within the acceptable range, marking the pixel as normal, when the temperature is greater than the acceptable range, marking the pixel as abnormal; and   generating an alert or cooling protocol when two or more adjacent pixels are marked as abnormal and having a temperature outside of the acceptable temperature range in the fixed field of view.   
     
     
         2 . The method of  claim 1 , comprising:
 providing a system for detecting the hotspot on the rotary kiln, the system comprising:
 at least one infrared imaging sensor directed at a rotary kiln, wherein the at least one infrared imaging sensor is directed at a tyre assembly of the rotary kiln so as to image at least 75% of a tyre gap surface of the tyre assembly; and 
 an imaging analysis computer operably coupled with the at least one infrared imaging sensor, wherein the imaging analysis computer includes one or more non-transient computer-readable media. 
   
     
     
         3 . The method of  claim 2 , wherein the at least one infrared imaging sensor is directed to a surface selected from at least one of:
 a kiln outer surface under the tyre assembly;   a surface of a tyre block of the tyre assembly; or   an under-surface of a tyre ring of the tyre assembly.   
     
     
         4 . The method of  claim 1 , further comprising:
 identifying a discrete area on a surface of the kiln in the fixed field of view; and   monitoring the discrete area when it passes through the fixed field of view as the kiln rotates.   
     
     
         5 . The method of  claim 4 , further comprising:
 identifying a plurality of discrete areas on a surface of the kiln in the fixed field of view that each have a temperature profile;   defining a temperature fingerprint with a collection of the plurality of discrete areas; and   monitoring the plurality of discreate areas of the temperature fingerprint as each passes through the fixed field of view as the kiln rotates.   
     
     
         6 . The method of  claim 4 , further comprising:
 identifying a first discrete area on the surface of the kiln in the at least one baseline infrared image of a fixed field of view of the rotary kiln;   identifying the first discrete area on the surface of the kiln in the at least one subsequent infrared image of the fixed field of view of the rotary kiln;   comparing the first discrete area from the at least one baseline infrared image to the first discrete area from the at least one subsequent infrared image;   determining differences in temperature for each pixel of the first discrete area from the at least one baseline infrared image to the at least one subsequent infrared image;   determining whether the first discrete area has a temperature difference greater than an allowable temperature difference; and   identifying the first discrete area as a hotspot when the temperature difference is greater than an allowable temperature difference.   
     
     
         7 . The method of  claim 2 , further comprising:
 monitoring at least one first discrete region of the tyre assembly and/or region of kiln surface underneath the tyre assembly;   determining a temperature profile for the kiln surface underneath the tyre assembly;   comparing the temperature profile with a model that correlates pixel temperatures with kiln brick wall thickness;   determining an estimated kiln brick wall thickness or brick fallout based on the temperature of each pixel in the temperature profile; and   generating and providing a report on the kiln brick wall thickness or brick fallout.   
     
     
         8 . The method of  claim 1 , further comprising:
 obtaining hotspot data for the kiln;   identifying at least one hotspot to cool with a cooling water spray;   determining a spraying protocol to cool the identified at least one hotspot;   implementing the spraying protocol to cool the identified at least one hotspot;   obtaining cooled temperature data for the at least one hotspot;   determining whether a cooled temperature of the hotspot is greater than the acceptable range; and   at least one of:
 when the cooled temperature is within the acceptable range, terminating the spraying protocol; or 
 when the cooled temperature is greater than the acceptable range, continuing the spraying protocol. 
   
     
     
         9 . The method of  claim 8 , wherein the hotspot data includes at least one of:
 a location of the hotspot in the kiln;   a surface of the kiln having a hotspot thereunder;   a temperature of the hotspot;   a temperature of the kiln surface over the hotspot;   an area size of the hotspot;   an area size of the kiln surface over the hotspot;   a temperature gradient of the hotspot;   a surface temperature gradient of the kiln surface over the hotspot;   a change in temperature from a baseline temperature for the hotspot; or   a change in temperature from a baseline temperature for the kiln surface over the hotspot.   
     
     
         10 . The method of  claim 9 , wherein the hotspot data includes current data compared to historical data, wherein the historical data includes at least one of:
 data prior to formation of a hotspot;   data from at least one prior rotation of the kiln;   data from the current hour;   data from the current day;   data from the current week; or   data from the current month.   
     
     
         11 . The method of  claim 1 , further comprising:
 identifying a location and hotspot data of a specific hotspot on the kiln; and   determining a spraying protocol to cool the specific hotspot based on at least one of:
 a water spray pressure; 
 a distance of a solenoid valve to the location of the specific hotspot on the kiln surface; 
 a distance of a solenoid valve to a nozzle; 
 a distance of a specific water sprayer to the location of the specific hotspot on the kiln surface; 
 time between actuating a solenoid valve of the specific water sprayer and contacting resultant water spray on the location of the specific hotspot; 
 duration of the location of the specific hotspot being within a spray region on the kiln surface; 
 duration of opening the solenoid valve; 
 rotational velocity of the rotating kiln; 
 temperature of sprayed water; 
 hottest temperature of the specific hotspot; 
 temperature profile of the specific hotspot; 
 temperature gradient and area of the hotspot; 
 temperature of sprayed water as it contacts the location of the specific hotspot; 
 when to initiate spray by actuating the solenoid valve; 
 when to terminate spray by de-actuating the solenoid valve; 
 position of the nozzle of sprayer relative to the location of the specific hotspot; 
 area of hotspot; or 
 area of water spray on the kiln surface. 
   
     
     
         12 . The method of  claim 11 , further comprising:
 determining timing of initiation of actuation of the solenoid valve relative to the location of the hotspot during rotation of the kiln;   determining time period the solenoid valve is opened to spray the cooling water; and   determining timing of de-actuation of solenoid valve relative to the location of the hotspot during rotation of the kiln, such that the water spray ceases as the hotspot moves out of range of the sprayer.   
     
     
         13 . The method  claim 11 , further comprising positioning each nozzle to spray water onto a defined spray area on the kiln, wherein each infrared imaging sensor of an infrared sensing system is positioned to image the kiln without imaging water vapor of the sprayed water. 
     
     
         14 . The method of  claim 13 , further comprising at least one of:
 positioning at least one nozzle to spray a water spray to cover at least 75% of a tyre gap surface of a tyre assembly of the kiln;   positioning a first nozzle to be aimed into a first open end of a first tyre gap of a tyre assembly of the kiln; or   positioning a second nozzle to be aimed into a second open end of the first tyre gap.   
     
     
         15 . The method of  claim 1 , further comprising:
 identify a first hotspot on a surface of the kiln in the fixed field of view; and   spraying water from at least one nozzle of a cooling system when the first hotspot passes through a spray region of the at least one nozzle when the first hotspot is outside of the fixed field of view.   
     
     
         16 . The method of  claim 15 , further comprising:
 monitoring a temperature profile of the first hotspot before, during, and after the spraying of water thereon;   determining whether the temperature profile of the first hotspot includes a temperature within an acceptable range; and   at least one of:
 not spraying the first hotspot when the temperature is within the acceptable range during each revolution of the kiln; or 
 spraying the first host spot when the temperature is greater than the acceptable range during each revolution of the kiln. 
   
     
     
         17 . The method of  claim 1 , further comprising driving at least one drive motor of a cooling system to change a trajectory of water spray from at least one nozzle of the cooling system toward at least one hotspot on the kiln. 
     
     
         18 . The method of  claim 1 , further comprising:
 determining a temperature of a discrete location of the rotary kiln in real time;   determining whether the temperature is greater than a threshold temperature in real time; and   generating an alert or cooling protocol in real time when the temperature is greater than the threshold temperature.   
     
     
         19 . The method of  claim 1 , further comprising:
 analyzing all pixels in the fixed field of view for changes from the at least one baseline infrared image of a defined region of the kiln to at least one subsequent infrared image having the defined region of the kiln;   identifying a variable difference in temperature for each pixel in the field of view between the at least one baseline infrared image and the at least one subsequent infrared image;   identifying one or more first pixels in the at least one subsequent infrared image having a first variable difference in temperature that is greater than an allowable variable difference in temperature for the one or more first pixels in the at least one subsequent infrared image compared to an allowable variable difference in temperature for the one or more first pixels in the at least one baseline infrared image;   determining the one or more first pixels as being one or more hotspots based on the first variable difference in temperature of the one or more first pixels being greater than the allowable variable difference in temperature of the one or more first pixels in the fixed field of view; and   generating an alert or cooling protocol that identifies a hotspot being present in the fixed field of view.   
     
     
         20 . The method of  claim 1 , comprising providing the alert by at least one of:
 actuating an audible indicator;   actuating a visible indicator;   showing the alert on a display device; or   transmitting the alert to a remote device.   
     
     
         21 . The method of  claim 1 , further comprising monitoring the fixed field of view to detect a hotspot under a tyre assembly of the rotary kiln. 
     
     
         22 . The method of  claim 1 , further comprising:
 identifying a surface region in the fixed field of view that is a surface of a tyre assembly, the surface region having a surface temperature for each pixel;   identifying a hotspot region of the kiln under the tyre assembly in the fixed field of view that is a hotspot by having a variable difference in temperature for each pixel that is greater than the allowable variable difference in temperature for the surface region from the at least one baseline infrared image to the at least one subsequent infrared image;   determine the surface region in the fixed field of view in the at least one baseline infrared image as being devoid of a hotspot, the surface region having the allowable variable difference in temperature for each pixel; and   determine the hotspot region in the fixed field of view in the at least one subsequent infrared image as having a hotspot, the hotspot region having the first variable difference in temperature that is greater than the allowable variable difference in temperature for each pixel.   
     
     
         23 . The method of  claim 1 , further comprising:
 associating adjacent first pixels to identify a hotspot region;   determining a size of the hotspot region; and   at least one of:
 generating a hotspot region size report that identifies the size of the hotspot region based on the associated adjacent first pixels; or 
 comparing the area of the hotspot region with a threshold area size and generate the alert or cooling protocol once the hotspot region has an area that is at least the size of the threshold size, wherein the threshold area size is a defined value or a percentage of a region of interest. 
   
     
     
         24 . The method of  claim 1 , further comprising at least one of the following:
 determining whether or not there is water on the kiln surface and compensate for the water during the analysis of the pixels in the fixed field of view;   determining whether or not there is water vapor rising from the kiln surface or from a water spray and compensate for the water vapor during the analysis of the pixels in the fixed field of view;   determining that it is raining in the fixed field of view and monitoring the fixed field of view to detect hotspots through the water;   determining whether or not the water on the kiln has areas of reflected light and compensate for the areas of reflected light during the analysis of the pixels in the fixed field of view;   obtaining the thermal data for the one or more surfaces in the fixed field of view and compute with the thermal data for the one or more surfaces in the fixed field of view during the analysis of the pixels in the fixed field of view;   obtaining distance data for the one or more surfaces in the fixed field of view and compute with the distance data for the one or more surfaces in the fixed field of view during the analysis of the pixels in the fixed field of view; or   determining a relative humidity and compute with the relative humidity during the analysis of the pixels in the fixed field of view.   
     
     
         25 . The method of  claim 1 , further comprising:
 acquiring a series of infrared images of the fixed field of view;   analyzing pixel data of each infrared image of the series to determine a pixel temperature for each pixel for each infrared image;   determining a range of pixel temperatures for each pixel without a hotspot being present in the fixed field of view across the series of infrared images of the fixed field of view; and   setting an allowable variable difference in temperature to include the determined range of pixel temperatures for each pixel without a hotspot.   
     
     
         26 . The method of  claim 1 , further comprising:
 acquiring a series of infrared images of the fixed field of view;   analyzing pixel data of each infrared image of the series to determine a pixel temperature for each pixel for each infrared image;   determining a range of pixel temperatures for each pixel without a hotspot being present in the fixed field of view across the series of infrared images of the fixed field of view;   performing a statistical analysis of the range of pixel temperatures for each pixel without a hotspot being present in at least one region across the series of infrared images of the fixed field of view for the at least one region to determine an allowable distribution of pixel temperatures for each pixel; and   setting the at least one baseline infrared image so that each pixel includes the allowable distribution of pixel temperatures.   
     
     
         27 . The method of  claim 1 , wherein the at least one baseline infrared image includes a model of each pixel with the allowable distribution of pixel temperatures for each pixel, wherein the model of each pixel is obtained by:
 determining a distribution of the pixel temperatures for each pixel without a hotspot being present across the series of infrared images for the at least one region;   identifying a maximum pixel temperature that is greater than the distribution of pixel temperatures by a first difference; and   setting the first difference from the distribution to indicate absence of a hotspot for each pixel in the at least one region.   
     
     
         28 . The method of  claim 27 , further comprising:
 comparing each pixel temperature in the one or more subsequent infrared images for the at least one region with the model of each pixel with the allowable distribution of pixel temperatures;   determining a difference between each pixel temperature in the one or more subsequent infrared images and the model of each pixel in the at least one region;   determining whether the difference is greater than a threshold difference; and   at least one of:
 when the difference is greater than the threshold difference, determining that the pixel is a hotspot pixel, or 
 when the difference is less than the threshold difference, determining that the pixel is not a hotspot pixel. 
   
     
     
         29 . The method of  claim 28 , further comprising:
 determining a standard deviation of the distribution of the pixel temperatures for each pixel without a hotspot being present across the series of infrared images; and   setting the threshold difference as being a defined difference from the standard deviation.   
     
     
         30 . The method of  claim 1 , further comprising:
 obtaining the at least one baseline infrared image of the fixed field of view of a specific rotational position of the rotary kiln such that a specific region of the rotary kiln is imaged by a plurality of specific pixels;   obtaining the at least one subsequent infrared image of the fixed field of view of the specific rotational position of the rotary kiln such that the specific region of the rotary kiln is imaged by the plurality of specific pixels; and   comparing the at least baseline one infrared image and the at least one subsequent infrared image so as to compare the specific region of the rotary kiln by the plurality of specific pixels,   wherein each rotational position of the rotary kiln is imaged as it rotates, and the comparison is made with each rotational position in the at least one baseline image and the at least one subsequent image.   
     
     
         31 . The method of  claim 1 , further comprising:
 identifying a physical feature of the rotary kiln; and   tracking the physical feature as the rotary kiln rotates.   
     
     
         32 . The method of  claim 31 , wherein the physical feature is at least one tyre gap of a tyre assembly of the rotary kiln. 
     
     
         33 . The method of  claim 1 , further comprising:
 receive input parameters of the rotary kiln, wherein the parameters include at least a measurement of dimension of the rotary kiln and at least a rotational velocity of the rotary kiln, wherein the dimensions include a diameter and/or length of the rotary kiln; and   at least one of:
 using the parameters in calculations for temperature profile measurements; or 
 using the parameters in calculating a rotational velocity of the rotary kiln. 
   
     
     
         34 . The method of  claim 33 , further comprising generating a 2D model of the rotary kiln based on the parameters of the rotary kiln. 
     
     
         35 . The method of  claim 34 , further comprising generating a 3D model of the rotary kiln based on wrapping the 2D model around a cylinder having the parameters of the rotary kiln. 
     
     
         36 . The method of  claim 34 , wherein the 3D model provides the at least one baseline infrared image.