JP7102535B2 - Flame image analysis for furnace combustion control - Google Patents

Description

In the present invention, in order to control and / or reduce the emission of carbon monoxide from the furnace, the material is heated, and the heating can cause the formation of carbon monoxide (which is a fuel and a gaseous oxidant). It relates to the operation of a combustion control system (meaning a closed space such as a combustion chamber to be burned).

The operation of heating the material in the furnace may result in the formation of carbon monoxide in the furnace. The mechanism by which carbon monoxide can be formed is incomplete combustion of fuel in the furnace, incomplete combustion of combustible material when burning the material heated in the furnace, and / or in the material to be heated or the like. Conversions involving conversion of carbonaceous materials above, thermal decomposition of carbonaceous materials or incomplete combustion can be mentioned. Examples of such conversions include thermal decomposition and / or incomplete combustion of carbonaceous materials.

When carbon monoxide is formed in the furnace, the release of carbon monoxide outside the furnace is usually undesirable. There are various techniques for removing carbon monoxide from the gaseous off-gas leaving the furnace, such as absorbing carbon monoxide onto an absorbent or adding a reactant to the off-gas that reacts with carbon monoxide. Such techniques present drawbacks such as implementation and control costs and difficulties.

The present invention provides an efficient method for avoiding the release of carbon monoxide from the furnace. It also provides an efficient method for controlling the operation of the furnace in order to obtain improved efficiency and production rate.

One aspect of the present invention is a method of heating a material in a furnace.
(A) The heat generated by the combustion of the fuel and gaseous oxidant supplied in the furnace in the furnace is used to heat the material containing carbonaceous substances in the furnace having a flue, thereby heating the material containing carbonaceous substances. To produce carbon monoxide derived from carbonaceous material, a flame that can extend from the flue to the outside of the furnace is formed in the furnace, heating and
(B) By electronically expressing at least one parameter corresponding to the intensity of the flame and corresponding to the concentration of carbon monoxide in the flame, the inside of the furnace or the inside of the furnace or by a digital camera located outside the furnace. From images of the flame taken outside the furnace, the concentration of carbon monoxide in the flame is characterized, from a given correlation between the actual concentration of carbon monoxide in the flame and the expressed value of at least one parameter. To determine the characteristic concentration of carbon monoxide in the flame,
(C) Comparing the characterized concentration of carbon monoxide in the flame characterized according to step (B) with a pre-established threshold concentration value for that concentration.
(D) When the characterized concentration of carbon monoxide in the flame exceeds the pre-established threshold concentration value, the characterized concentration of carbon monoxide in the flame is increased for a predetermined time period. The amount of oxygen, fuel, or amount of oxygen supplied in the furnace that is available to react in the furnace to an amount (s) that is effective for lowering below a pre-established threshold concentration value. The method involves adjusting the amount of both oxygen and fuel while continuing to characterize the concentration of carbon monoxide in the flame from images of the flame taken with a digital camera outside the furnace.

Another aspect of the present invention is a method of producing molten glass.
(A) The heat generated by the combustion of the fuel and gaseous oxidant supplied in the furnace in the furnace is used to heat the material containing carbonaceous substances in the furnace having a flue, thereby heating the material containing carbonaceous substances. To produce carbon monoxide derived from carbonaceous material, a flame that can extend from the flue to the outside of the furnace is formed in the furnace, heating and
(B) By electronically expressing at least one parameter corresponding to the intensity of the flame and corresponding to the concentration of carbon monoxide in the flame, the inside of the furnace or the inside of the furnace or by a digital camera located outside the furnace. From images of the flame taken outside the furnace, the concentration of carbon monoxide in the flame is characterized, from a given correlation between the actual concentration of carbon monoxide in the flame and the expressed value of at least one parameter. To determine the characteristic concentration of carbon monoxide in the flame,
(C) Comparing the characterized concentration of carbon monoxide in the flame characterized according to step (B) with a pre-established threshold concentration value for that concentration.
(D) When the characterized concentration of carbon monoxide in the flame exceeds the pre-established threshold concentration value, the characterized concentration of carbon monoxide in the flame is increased for a predetermined time period. Outside the furnace, adjusting the amount of oxygen supplied in the furnace that is available to react with carbon monoxide in the furnace to an amount effective to reduce it below a pre-established threshold concentration value. A method that includes continuing to characterize the concentration of carbon monoxide in the flame from images of the flame taken with a digital camera.

It is a schematic diagram which shows how this invention can be mounted on a furnace apparatus. It is a figure which shows the order of the steps of this invention.

The present invention is useful for heating any material that can be heated in a furnace. Examples of such materials include iron metals such as iron and steel, as well as final products and scraps, as well as steel and other compounds. Further examples include final products and scraps such as aluminum and copper, and non-ferrous metals such as aluminum and copper, including ores and other compounds thereof. Using heating of any such material, prepare them for further chemical and / or physical treatment.

The present invention is also useful for heating a material in which some or all of the material is melted. In such operations, the material may contain any of the aforementioned metals, metal oxides, and other metal compounds. Other examples include products that are melted together in a glass making furnace to form molten glass, such materials include recycled glass pieces known as cullet, as well as together to make glass. Examples include raw materials known as batches that are melted into, such as sodium oxide, potassium oxide, and materials containing sodium and potassium silicates. Another example of such operation is that raw materials typically containing lime or limestone, as well as raw materials containing silica and / or aluminosilicate (clay) and other desired additives, melt and react with each other to cement. A cement kiln that is heated together to form the constituent compounds of.

The present invention is also useful for heating a material in which part or all of the material is incinerated, such as an incinerator. Materials that can be heated in the practice of this aspect of the invention include all flammable products such as carbonaceous fuels, solid wastes and the like.

All materials treated according to the present invention are characterized by the fact that they contain some carbonaceous material, so that when the material is heated, carbon monoxide can be formed from the carbonaceous material in the furnace. The carbonaceous material present may be an organic compound present in the material being heated and / or may include some or all of the material that has been heated and then burned in the furnace. For example, scrap containing aluminum, copper, iron and / or steel may carry paints or other organic coatings, organic foods and / or carbonaceous materials such as urine. The cullet present in the glassmaking material may carry an organic substance that is a residue of food products or other organic matter that was present on the cullet before it was recycled as a cullet.

The carbon monoxide formed in the furnace may be produced by any one or more of several possible mechanisms, such as incomplete combustion of fuel in the furnace, and may be a material that is heated in the furnace. Examples of incomplete combustion of flammable materials in combustion and / or conversion of carbonaceous materials in or on the material to be heated, thermal decomposition or incomplete combustion of carbonaceous materials. Is also intended. Just as carbon monoxide emission from a furnace is undesirable regardless of the source of carbon monoxide, the present invention relates to sources or mechanisms by which carbon monoxide that is at risk of being released from the furnace is formed. Useful regardless.

With reference to FIG. 1, the furnace 1 is shown in cross section. The illustrated furnace has the typical shape of a furnace that can be rotated about an axis that is horizontal in the embodiment shown in FIG. 1, but the present invention, along with any other type and shape of the furnace. It may be carried out. In the furnace 1, the material to be heated is represented as 2. The material 2 is heated by heat from the flame 4 formed in the furnace by burning the fuel 13 with the oxidant 12 in the burner 11. The suitable fuel 13 may be any flammable carbonaceous material, and preferred examples thereof include methane, natural gas, and atomized fuel oil. Suitable oxidants supplied in 12, include oxygen such as air, oxygen-enriched air, and any gaseous product containing a stream having an oxygen content of at least 50% by volume, preferably at least 90% by volume. Can be mentioned. Streams with such increased oxygen content are commercially available from any of several sources of atmospheric gas. Although one flame 4 is shown, a furnace in which the present invention can be put into practical use may include two or more burners 11 and two or more flames 4.

The furnace 1 includes at least one flue 6 through which gaseous products can exit the furnace 1. The gaseous product passing through the flue 6 contains a gaseous product of combustion between the oxidizing agent 12 and the fuel 13 such as carbon dioxide and water vapor, and contains a volatile organic compound (VOC). It may be contained or may contain carbon monoxide. In the practical application of the present invention, if only one flue 6 is present, the flame 15 can extend from the outlet 7 of the flue 6. If there are two or more flues 6, there may be a flame 15 extending from at least one outlet 7 of at least one flue 6. Carbon monoxide may be present in the flame 15 and may or may not be completely burned in the flame 15.

The furnace 1 may include a peep port 10 in the wall of the furnace in which the flame 4 inside the furnace 1 can be observed from the outside of the furnace 1.

According to the present invention, the camera 21 is positioned outside the furnace 1. The camera 21 includes an opening 22 in which the camera 21 receives an image. In one embodiment of the invention, the camera 21 is positioned relative to the furnace 1 so that the opening 22 of the camera 21 is directed toward the flame 15. In another embodiment of the invention, the camera 21 allows the camera 21 to receive an image of the flame 4 inside the furnace 1 so that the opening 22 of the camera 21 is aligned with the viewing port 10. Positioned with respect to furnace 1.

The camera 21 is a digital camera, detecting that the camera 21 detects one or more characteristics of an object (in this case, the detected characteristics include at least the intensity of the flame to which the camera 21 is directed). It means that the image corresponding to the detected characteristic is electronically represented in a digital format. Digital cameras with this capability are commercially available. These may be stand-alone units or may be part of an item of equipment with additional functional capabilities (telephone, timekeeping, etc.).

Further referring to FIG. 1, the control unit 25 controls the flow rates of the oxidant 12 and the fuel 13 with respect to the burners 11 (or to a plurality of burners if two or more burners 11 are present). Optional, but preferably, a lance 27 is provided to release the supplemental oxidant into the furnace 1 as the additional oxidant is transferred into the furnace 1. The flow of the oxidant through the lance 27 is controlled by the control unit 29. The oxidant that can pass through the lance 27 in the furnace 1 can be air, oxygen-enriched air, or a high-purity oxidant having an oxygen content of at least 50% by volume, even at least 90% by volume. The oxygen content of the oxidant supplied into the furnace 1 via the lance 27 may be the same as or different from the oxygen content of the oxidant 12 supplied to the furnace 1.

In FIG. 1, block 23 refers to a complete system that performs a series of steps shown as 31, 33 and 35 in FIG. The system can be in one integrated device, or the components that perform a particular step are physically separated from the other components and from each other by suitable cables or by cableless wireless connections. Can be connected. A part or all of the parts can be included in the camera 21. However, to facilitate functionality, and the camera 21 may be located in an environment that can be hot and dusty, and therefore potentially harsh to components such as processors. Therefore, it is preferred that the camera 21 is physically separated from the other components and the camera 21 is connected by cable or wireless connection to at least the component that performs the first step 31 following the acquisition of the image by the camera 21. .. As seen in FIG. 1, the system 23 is connected to the camera 21 to receive input from the camera 21, and the system 23 is connected to the control unit 25 and (if present) to the control unit 29 to control 25. And 29 are signaled.

During operation, combustion is performed inside the furnace 1 in the presence of the material 2 in the furnace 1. The flame is formed in a furnace that can appear as a flame 15 extending from the opening 7 of the flue 6. In one embodiment of the invention, the camera 21 is directed at the flame 15 so that the image of the flame 15 is received through the opening 22. In another embodiment of the invention, the camera 21 is directed towards the furnace 1 so that the image of the flame 4 inside the furnace 1 is received by the opening 22 through the viewing port 10. The flame 15 or 4 may be very bright, so the aperture 22 and exposure should be adjusted to prevent blooming of the image. In some situations, it may be desirable to be able to dynamically adjust the exposure of an image so that the appropriate resolution is achieved when the image is very dark. In most situations, such dynamic regulation is not necessary. The view factor and resolution of the camera image should be such that the image size is at least 50 x 50 pixels, preferably at least 300 x 300 pixels. One of ordinary skill in the art can easily determine the appropriate image resolution and image view factor for a given distance of the camera 21 from the flame 15 or 4 and for a flame 15 or 4 of a given size. The camera 21 generates a digital electronic image of the flame 15 or the flame 4 based on at least one parameter of the flame, such as the intensity of the flame 15 or the flame 4. The electronic image is electronically transmitted by the camera 21 to the device performing step 31.

In step 31, the signal corresponding to the image of flame 15 or 4 is converted into one or more values representing the intensity of the flame or various intensities, including a range of values over the area of the flame within the field of view of the camera 21. It may be. Intensities are detected and digitally represented to produce an array of values corresponding to the detected intensities. The detected intensity parameters also correspond to the concentration of carbon monoxide present in the flame.

In step 33, the detected intensity parameter is compared to a pre-established correlation of the intensity parameter with respect to the actual concentration of carbon monoxide in the flame. Pre-established correlations simultaneously measure the concentration of carbon monoxide in the flame through established techniques such as gas sampling using a gas sampling probe, followed by analysis of the sampled gas, or continuous emission monitoring. Observe the value of the expression parameter derived in step 31 from the value based on the intensity detected by the camera 21, and place it in a place such as a computer or a written catalog where the measured concentration and parameter value can be read together. It can be established by recording. Thus, each intensity parameter represented by the system corresponds to the actual concentration of carbon monoxide in the flame. Determining the existing correlation between the expressed parameters and the measured carbon monoxide concentration can already be performed during the initial setup of the system in the furnace and is typically performed each time the furnace is in operation. It does not have to be repeated in a given furnace. However, it may be preferable for the operator to establish a new set of correlations for different furnaces, as well as for a given furnace, in situations where the conditions for operating a given furnace are significantly different.

The systems described herein can be used to achieve any of several methods of controlling furnace operation. One such method is to control carbon monoxide release by controlling the supply of oxygen to the furnace, which is described herein below.

The operation of the furnace will have a pre-established value of the carbon monoxide concentration in the flame so that the carbon monoxide concentration value above that value is unacceptable and always falls below that value. Typical values for excess carbon monoxide can range from 3% to 30% by volume, but will vary depending on the location, the nature of the material 2 being heated in the furnace 1, or other conditions. obtain. Pre-established values represent an excessive risk of environmental hazards, or a risk of breach of applicable environmental regulations, or an undesired imbalance of economic and thermodynamic conditions in the reactor. Based on factors or groups of factors that are important to the operator, such as the values shown.

In step 33, a pre-established value of the carbon monoxide concentration in the flame (which may also be called a threshold or set point) is stored and detected corresponding to the carbon monoxide concentration in the flame at a given point in time. Compare the strength parameters with the pre-established thresholds. The comparison can be performed at any desired rate, but preferably the comparison is performed once every 2-5 seconds. Preferably, the comparison is automatically performed by a well-programmed controller.

When the detected and processed intensity parameters correspond to the actual carbon monoxide concentration in the flame that exceeds the pre-established threshold, the system takes action to provide additional oxygen in the furnace 1. do. In FIG. 2, this action is represented in step 33 as activating the combustion control system 35 to generate a signal for the presence of additional oxygen in the furnace 1. The additional oxygen reacts with the carbon monoxide present in the furnace so that less carbon monoxide exits the furnace 1 through the flue 6 in the flame 15 or otherwise. Additional oxygen can be provided into furnace 1 and reacted with the detected excess carbon monoxide in any of several modes. For example, one such mode is for the control system 35 to increase the amount of oxygen 12 supplied into the furnace 1 through the burner 11 without increasing the flow rate of the fuel 13 into the furnace 1. belongs to. Another possible mode is to supply the supplemental oxidant through the auxiliary supply line 29 (shown in FIG. 1) without increasing the flow rate of the fuel 13 into the furnace 1, or supplementary. To increase the amount of oxygen. Yet another possible mode is to reduce the amount of fuel 13 supplied into the furnace 1 without reducing the amount of oxygen 12 or auxiliary oxygen 27 supplied to the furnace 1. Alternatively, any combination of these modes can be implemented at the same time.

A preferred embodiment is to provide auxiliary oxygen 27 so that the operator does not have to adjust the stoichiometric ratio of the oxidant and fuel supplied through one or more burners 11. The auxiliary supply line 27 is preferably carbon monoxide, preferably in a region in the furnace where a relatively large amount of carbon monoxide can be present, or in the vicinity of a region where the inside of the furnace 1 is connected to the upstream end of the flue 6. It should be positioned to supply the oxidant to no area.

It continues until the detected and processed values representing the carbon monoxide concentration in the flame are reduced to below the pre-established thresholds described above. Preferably, the additional oxygen provides additional oxygen until the detected and processed values are below the pre-established threshold, eg, the pre-established threshold is 0.5% to less than 2%. It should be provided to minimize the number of times the supply of additional oxygen is started and then interrupted.

Steps 31, 33, and 35 can be performed within a well-programmed controller that is connected to each other by a suitable cable or by a wireless connection. Alternatively, they may all be in one part of the hardware.

As shown, the systems described herein achieve the desired combustion characteristics in the furnace or from start-up by regulating the supply of oxygen (oxidizer), fuel, or both oxygen and fuel. It can also be used to perform operating control of the furnace. In this embodiment of the invention, one set point or more than one set point (typically 3 to 10 set points) is pre-established in the controller corresponding to the fuel flow rate to the furnace and the oxygen flow rate. (If the furnace has multiple burners, in one burner or in each of the burners).

In these embodiments, the image analysis parameters are received in step 33 and compared to user-defined control level setting points that preset the flow rate values and oxidant lances for each level used in the burner. This last part communicates with the furnace combustion control PLC. The user can also select other process parameters such as a timer that activates / deactivates the control level. The user may also select the language that appears on the control panel that the operator will see, or may select other variables that are controlled. The controller 33 collects data from the camera and related software, processes this data with user inputs (limits, oxygen flow set points, natural gas flow set points, delay times) and dynamically adjusts the process. Reduce CO emissions and increase furnace production.

The user selects a control variable and has a start limit, a stop limit, and an "off delay" value (any number of each required, typically 1-10 each, and a "delay" value (typically). 1 to 5) Set the number. The user also sets the oxygen flow setting point and the burner natural gas flow setting point for each corresponding limit. The first start limit exceeds the on-delay time. When the software sets the corresponding oxygen flow set points and natural gas flow set points. The set points are processed in the order in which the limits are exceeded. When the control variable falls below the stop limit and the off-delay timer completes, The previous level is set.

When the control variable drops below all stop limits and the final off-delay ends, the oxygen set point is set to zero and the burner fuel set point is returned to normal control.

When the furnace door is opened, the oxygen set point is set to zero and the burner fuel set point is returned to normal control.

The systems and methods described herein allow the operator to realize benefits in the operation of the furnace, such as more efficient operation, such as fuel consumption and reduced cycle times. By monitoring the carbon monoxide content in the flame (and by doing so in real time, this is how the invention can be utilized), the operator can dissipate the heat of combustion of carbon monoxide. The oxygen and / or fuel supply rate can be adjusted to the furnace so that it can be retained and utilized in the furnace, which allows the operator to heat and / or heat the materials in the furnace in a shorter cycle time. It allows the same degree of melting to be achieved and allows the operator to heat and / or melt less fuel consumption per unit of heated material.

The present invention is an advantageous method for controlling carbon monoxide emissions from a furnace and controlling the operation of the entire furnace. One reason is that the implementation of the method of the present invention in an operating furnace does not require an ongoing direct measurement of the concentration of carbon monoxide in the flame. Another reason is that the present invention detects parameters that characterize carbon monoxide in the flame rather than flue gas or exhaust gas, and the measurements tend to be more variable and unreliable. Also, the method of the present invention is not based on measuring the flame temperature and is not based on measuring the difference in flame temperature, and is therefore more reliable and vulnerable to flame temperature fluctuations. low. Instead, the method of the present invention is based on the correlation of image parameters corresponding to the carbon monoxide concentration in the flame, which is considered to be a novel and efficient mode of operation.

Other advantages are reduced maintenance requirements for the equipment used, lower installation costs, and little or no furnace downtime to install the system performing the present invention. , And when the system detects a condition that requires an increase or other change in the amount of oxygen and / or the amount of fuel supplied to the reactor, it adjusts the oxygen supply, fuel supply, or both oxygen supply and fuel supply. There is a faster response time to do.

Claims (12)

It is a method of heating the material in the furnace.
(A) The material containing a carbonaceous substance is heated in a furnace having a flue by using the heat generated by the combustion of the fuel and the gaseous oxidizing agent supplied in the furnace in the furnace. Thereby, by producing carbon monoxide derived from the carbonaceous material, a flame that can extend from the flue to the outside of the furnace is formed in the furnace and is heated.
(B) An image for detecting the intensity of the flame outside the flue is taken by a digital camera located outside the furnace.
The image corresponding to the detected intensity is electronically represented in a digital format.
By electronically representing at least one parameter corresponding to the detected intensity of the flame and corresponding to the concentration of carbon monoxide in the flame, by the digital camera located outside the furnace. From the image of the detected intensity of the flame taken outside the furnace, the concentration of carbon monoxide in the flame is characterized and the actual concentration of carbon monoxide in the flame and at least one of the above. Determining the characterized concentration of carbon monoxide in the flame from a given correlation with the expressed values of the two parameters.
(C) Comparing the characterized concentration of carbon monoxide in the flame characterized according to step (B) with a pre-established threshold concentration value for the concentration of carbon monoxide in the furnace. When,
(D) When the characterized concentration of carbon monoxide in the flame exceeds the pre-established threshold concentration value, the characterized concentration of carbon monoxide in the flame is determined. Supplied in the furnace available for reaction in the furnace to an amount (s) effective for reducing below the pre-established threshold concentration value over a period of time. The concentration of carbon monoxide in the flame is characterized from the image of the flame taken by the digital camera outside the furnace, adjusting the amount of oxygen, the amount of fuel, or the amount of both oxygen and fuel. To continue that and
Including
The method is a method that does not measure the temperature of the flame and is not based on measuring the difference in flame temperature. The method of claim 1, wherein the material comprises a metal. The method of claim 1, wherein in step (A) at least a portion of the material being heated is burned. The method of claim 1, wherein in step (A) at least a portion of the material being heated is melted. In step (D), adjusting the amount of oxygen in the furnace available for reaction in the furnace can be used in the furnace relative to the amount of fuel supplied in the furnace. The method of claim 1, comprising increasing the amount of oxygen supplied. In step (D), adjusting the amount of oxygen in the furnace available for reaction in the furnace can be used in the furnace relative to the amount of oxygen supplied in the furnace. The method of claim 1, comprising reducing the amount of said fuel supplied. 1. A claim comprising adjusting the amount of oxygen supplied into the furnace when the characterized concentration of carbon monoxide in the flame exceeds the pre-established concentration value. The method described in. 1. A claim comprising adjusting the amount of fuel supplied into the furnace when the characterized concentration of carbon monoxide in the flame exceeds the pre-established concentration value. The method described in. Adjusting the amount of oxygen and fuel supplied into the furnace when the characterized concentration of carbon monoxide in the flame exceeds the pre-established concentration value. The method according to claim 1, which comprises. It is a method of heating the material in the furnace.
(A) The fuel and gaseous oxidizing agent supplied into the furnace use the heat generated by combustion in the furnace to heat a material containing a carbonaceous substance in a furnace having a flue. Thereby, by producing carbon monoxide derived from the carbonaceous material, a flame that can extend from the flue to the outside of the furnace is formed in the furnace and is heated.
(B) An image for detecting the intensity of the flame outside the flue is taken by a digital camera located outside the furnace.
The image corresponding to the detected intensity is electronically represented in a digital format.
By electronically representing at least one parameter corresponding to the detected intensity of the flame and corresponding to the concentration of carbon monoxide in the flame, by the digital camera located outside the furnace. From the image of the detected intensity of the flame taken outside the furnace, the concentration of carbon monoxide in the flame is characterized, and the actual concentration of carbon monoxide in the flame and at least one of the above. Determining the characterized concentration of carbon monoxide in the flame from a given correlation with the expressed values of the two parameters.
(C) Comparing the characterized concentration of carbon monoxide in the flame characterized according to step (B) with a pre-established threshold concentration value for the concentration of carbon monoxide in the furnace. When,
(D) When the characterized concentration of carbon monoxide in the flame exceeds the pre-established threshold concentration value, the characterized concentration of carbon monoxide in the flame is determined. Supplied into the furnace, which is available to react with carbon monoxide in the furnace to an amount effective to reduce it below the pre-established threshold concentration value during the length of time. Continuing to characterize the concentration of carbon monoxide in the flame from the image of the flame taken by the digital camera outside the furnace while adjusting the amount of oxygen.
Including
The method is a method that does not measure the temperature of the flame and is not based on measuring the difference in flame temperature. In step (D), adjusting the amount of oxygen in the furnace available to react with carbon monoxide in the furnace is relative to the amount of fuel supplied into the furnace. 10. The method of claim 10 , comprising increasing the amount of oxygen supplied into the furnace. In step (D), adjusting the amount of oxygen in the furnace that is available to react with carbon monoxide in the furnace is relative to the amount of oxygen supplied into the furnace. 10. The method of claim 10 , comprising reducing the amount of the fuel supplied into the furnace.

Images