[0032] The present invention will be further elaborated and illustrated below in conjunction with the drawings and specific embodiments. The technical features of the various embodiments of the present invention can be combined accordingly without conflict with each other.
[0033] Such as figure 1 Shown is the overall equipment for the bromine distillation process provided in a preferred embodiment of the present invention. The main body of the equipment is a distillation tower, and the inside of the distillation tower is used for the distillation and purification reaction of chlorine and steam. Two transparent windows are opened on the side wall of the distillation tower opposite to each other. One window is used to install the industrial visual recognition system, and the other window is installed with a light source to fill the reactants inside the tower. The image obtained by the industrial visual recognition system is clearer. The industrial visual recognition system can be realized by using corresponding equipment in the prior art without any special limitation, as long as the color depth of the reactant in the image can be recognized.
[0034] The bottom of the distillation column is connected to the steam feed pipe and the chlorine feed pipe. The chlorine feed pipe is equipped with a flow meter 1 and a regulating valve 1, and the steam feed pipe is equipped with a flow meter 2 and a regulating valve 2, two sets of flow meters and regulating valves The chlorine and steam input into the distillation tower can be adjusted and metered separately. In this embodiment, during the process operation, the feed amount of steam is set as required and then kept at a preset fixed value for a long time, and the feed amount of chlorine is mainly adjusted through the regulating valve 1. The feed ratio of chlorine and steam will affect the color depth of the internal reactants. When chlorine is not added enough, the color of the reactants will be too dark, and when the chlorine is added too much, the color of the reactants will be too light. The key of the present invention is to use an industrial visual recognition system that can be set at the position of the window to monitor the color depth of the reactant in real time, and then the color depth is used as a reference to feedback control the chlorine inflow, so that the ratio of the two The best condition, to ensure the best quality of bromine. The mother liquor enters from the top of the distillation tower, the finished product is discharged from the top, and the waste liquid is discharged from the bottom of the tower.
[0035] Below figure 1 The shown equipment is taken as an example to describe the specific realization of the chlorination control method based on visual recognition in the bromine distillation process of the present invention.
[0036] In this method, it is necessary to determine the operating state of the best bromine quality in the bromine distillation process based on historical experiments or manual operation experience and the quality of the produced bromine as the standard, and then determine when the best bromine quality can be obtained The best color depth corresponding to the reactant image in the tower. The color depth of the reactants in the distillation tower is determined by the magnitude of the numerical signal obtained after the image of the reactants is recognized by the visual recognition method. The visual recognition method mentioned here is used to recognize the color shade information in the image. The color depth, that is, the depth information, can be converted into the color depth value of the image color information obtained by visual collection through the color depth conversion algorithm. The specific conversion algorithm can be implemented in any feasible way in the prior art, such as calculating its gray value based on R, G, and B, displaying the color depth information in gray, or other corresponding algorithms, which are not limited. Generally speaking, the darker the color, the smaller the color depth value, which means that the chlorine is insufficiently added; on the contrary, the lighter the color, the greater the color depth value is, and the chlorine is added excessively.
[0037] The determined optimal color depth is a value. Although the subsequent process can be judged and adjusted based on this value, the internal reaction itself fluctuates in the actual process, so the color depth of the reactant is also fluctuating. In general, the optimal color depth of the reactant that can produce the best bromine quality can be set to a rough range, which is more maneuverable than a single value. Therefore, a certain range can be extended based on the aforementioned optimal color depth value. A preferred implementation method is: taking the best state when the bromine distillation process can produce the best bromine quality during the operation of the bromine distillation process, obtain the image of the reactants in the distillation tower under the best state, and then use the visual recognition method The color depth value conversion process is performed on the image to obtain the numerical signal size corresponding to the color depth of the reactant in the image; based on the numerical signal, the numerical range is expanded to both sides of the numerical value to represent the optimal color depth interval. In the actual operation process, the value of the extended range on both sides needs to be determined based on on-site process experience or multiple optimizations to ensure that the optimal color depth interval is reasonable and accurate.
[0038] In addition, since the control valve on the chlorine feed pipe, that is, the regulating valve 1, needs to assume the function of changing the chlorine feed amount. In the specific implementation, it is necessary to pre-set a maximum valve opening range of the regulating valve as a reference basis Adjust the opening quickly. Therefore, a preferred implementation method is to determine the opening value of the control valve on the chlorine gas feed pipe in this state according to the previously determined operating state of the best bromine quality, and based on the opening value, follow the previous test operation The experience is extended to both sides of the value respectively to form the opening range of the control valve on the chlorine feed pipe. Similarly, the specific expansion range needs to be determined based on on-site process experience or multiple optimizations, and the maximum control interval of the valve should be set reasonably, and a certain adjustment margin should be left when necessary, so as to avoid unnecessary excessiveness while ensuring a wide range of adjustments. adjust.
[0039] The above determined optimal color depth range of the reactants in the distillation tower and the opening range of the control valve on the chlorine feed pipe can be pre-stored in the host computer as the reference data for subsequent judgment and control. Although the approximate opening range of the valve can be determined based on experience, due to the instability of the raw material feed difference, the temperature, pressure and acid concentration in the distillation column, the reaction process will fluctuate and the reaction equilibrium point cannot be found quantitatively. Adding chlorine in a uniform amount will result in excessive acid or low bromine output. Therefore, it is necessary to dynamically adjust the amount of chlorine added to find the relative reaction equilibrium point. The following describes in detail how to realize the dynamic automatic control of chlorination based on visual recognition during the process operation.
[0040] During the operation of the bromine distillation process, the color depth of the reactants in the current distillation tower is monitored in real time through visual recognition methods. It should be noted that in order to ensure the comparability of the data, the visual recognition method used here needs to be consistent with the method used to determine the benchmark data (optimal color depth interval, valve opening range). For the color depth value of the reactant in the current distillation tower obtained in the real-time monitoring process, it is necessary to determine whether the current reactant color depth is within the optimal color depth interval determined above. There are two judgment results: if the current reactant color If the depth deviates from the optimal color depth range, the control valve opening is adjusted within the previously determined control valve opening range to restore the current reactant color to the optimal color depth range; if the current reactant color depth does not deviate from the maximum The best color depth range can be regarded as the current chlorination amount is appropriate, and the valve opening adjustment is not performed. The control relationship between the color depth of the reactants and the opening of the control valve on the chlorine feed pipe is: when the color needs to be darkened, reduce the control valve opening and reduce the amount of chlorine added; when the color needs to be lightened, increase Large control valve opening, increase the amount of chlorine added.
[0041] In the specific valve opening adjustment process, the opening adjustment step length of each time can be determined according to actual needs, and it can be a fixed value or an unfixed value. The value of the step size needs to be designed reasonably. Too large will cause the single adjustment range to be too large, and the internal response fluctuates too sharply, and it is difficult to adjust to the optimal value; but the step size is too small to easily cause the adjustment to take too long and efficiency. low. Moreover, due to the non-synchronization between the adjustment of the amount of chlorine added and the color change of the reactants, a preferred implementation is: when the color depth of the reactants deviates from the optimal color depth interval, the opening of the control valve needs to be adjusted every time After the adjustment action is performed, it needs to run stably for a certain period of time (the specific time can be adjusted), and then monitor and judge the color depth of the current reactant again, and then decide whether to perform the next adjustment action according to the judgment result. If after this adjustment, the current reactant color depth has returned to the optimal color depth range, no further adjustment is needed in the next step. If after this adjustment, the current reactant color depth has not returned to the optimal color depth range, then In the next step, you can continue to change the valve opening according to the adjustment direction of the color depth. If a single adjustment is excessive, it needs to be called back again.
[0042] For the situation where the currently monitored color depth of the reactant is within the optimal color depth range, it indicates that the overall response is in a better state. But in fact, the previously determined optimal color depth interval itself has a certain range, so even if the current color is within this interval, it does not mean that the amount of chlorine added is completely in line with the optimal ratio. Because the bromine extraction reaction has a hysteresis through the color observation in the distillation tower, there is a time difference between the addition of chlorine and the color change of the reactants. If there is a little excess or shortage of chlorine, even if the current color is in the optimal range, it will change over time. Gradually deviate from the optimal interval. If the current color depth of the reactant is within the optimal color depth range, the valve opening adjustment is not performed at all, which may result in the actual quality of bromine produced is not optimal, and there is also a waste of raw materials. Therefore, the present invention can further provide a preferred implementation method based on the above process, that is, if the current color depth of the reactant is within the optimal color depth range, a predictive control process needs to be executed to eliminate the influence of control hysteresis. The specific process of the predictive control process is as follows:
[0043] When the current color depth of the reactants is within the optimal color depth range, then it is necessary to continuously monitor the color depth of the reactants in the distillation tower at regular intervals, except to determine whether the current color depth is within the optimal color depth range. In addition, it is also necessary to determine the change trend of the color depth within a certain monitoring period. If the color of the reactants in the distillation tower has a continuous darkening or lightening trend, adjust the current control valve opening in the direction to prevent this trend until the color of the reactants in the distillation tower no longer has a continuous darkening or lightening trend . If there is no continuous deepening or shallowing trend, there is no need to adjust the valve opening of the chlorine feed pipe. The continuous darkening or lightening trend means that at several consecutive monitoring time points, the color depth of the reactant at the next time point has darkened compared to the previous time point; or at several consecutive monitoring time points , The color depth of the reactant at the latter time point is lighter than that at the previous time point. If during this period of time, part of it deepens and part of it becomes shallower, it can be regarded as mere fluctuation, and there is no continuous trend.
[0044] From the perspective of specific implementation, the method for judging the color depth change trend of the reactants in the distillation tower can be implemented in the following ways:
[0045] During the continuous period, the color depth of the reactants in the distillation tower is monitored at intervals. When the color depths of N consecutive monitoring periods are darkened (or lighter) that tends to be uniform, the color depth of the reactants in the distillation tower is determined The color has a continuous darkening (or lightening) trend. When the color depth of N consecutive monitoring periods appears inconsistent darkening or lightening, it is judged that the color of the reactant in the distillation tower is in a fluctuating state, and there is no need to adjust the control valve opening . The above trend refers to the color change trend of the two monitoring time points before and after, that is, the color changes from dark to light, or from light to dark. In this process, N takes a natural number of at least 2. However, when N is only 2, there are too few samples to distinguish the inevitable fluctuations in the reaction, and it is easy to identify such fluctuations as color changes caused by unreasonable chlorination. Therefore, the absolute amount of color depth change can be used to assist judgment. Of course, N can also consider setting a larger value to accurately identify the trend, but N should not be too large to prevent the identification process from being too long and the sensitivity of adjustment reduced.
[0046] In the above-mentioned control method, the data needs to be continuously monitored and then fed back and adjusted. Therefore, a supporting automatic control system is needed to realize the automatic operation of the method and reduce the amount of manual operation. An implementation of the automatic control system is given below. Such as figure 2 As shown, the automatic control system includes an industrial visual recognition system A, a data conversion module B, a host computer control system C, and a control execution system D.
[0047] Among them, the industrial visual recognition system A is installed at the view port of the distillation tower, and the supplementary light source is placed on the opposite view port, and it is completely covered with a glass fiber reinforced plastic cover, and the on-site components are installed in the glass fiber reinforced plastic cover. The industrial visual recognition system can take images of the reactants of internal chlorine and water vapor through the imaging system, and then recognize the color depth of the reactants in the distillation tower.
[0048] The data conversion module B is installed between the industrial vision system and the upper computer control system, and is arranged according to the on-site working conditions. The data conversion module is used to perform analog-to-digital conversion on the recognized color depth of the reactant and transmit the digital signal to the upper computer control system.
[0049] The upper computer control system C is used to process the received color depth data, determine whether the color depth of the current reactant is in the optimal color depth interval, and send the control valve opening adjustment command to the control execution system according to the judgment result. The specific The judgment process and the valve control information given according to the judgment result are as described above. The upper computer control system mainly consists of an industrial computer and a display screen, which is installed in the central control room. The video parameters recognized by the upper computer software are displayed on the display screen in real time. At the same time, the data parameters and control instructions recognized by the host computer system can be transmitted to the control execution system in real time to realize automatic control. The aforementioned pre-judgment control process can also be executed as a module by the host computer control system.
[0050] The control execution system D can adopt a DCS system, etc., to accurately adjust the opening of the regulating valve 1 on the chlorine gas feed pipe according to the received adjustment instruction.
[0051] The following further uses a specific embodiment to show the process of the present invention, so that those skilled in the art can better understand the essence of the invention.
[0052] 1. First, according to the manual operation experience and the quality of the finished product, find the best color depth of the reactant and convert it into a color depth value, such as 34. Record the valve opening information corresponding to the best color, such as 50. The darker the on-site color, the smaller the color depth value, which means that the chlorine is not added enough; on the contrary, the chlorine is added too much.
[0053] 2. After identifying the best color depth as a numerical signal through system recognition, expand to both sides based on its value, and set an optimal color depth interval, for example: 30-38. At the same time, based on the valve opening corresponding to the best color, set the valve control interval, such as 48-52 (this value is judged by on-site process experience, the maximum valve control interval), in order to ensure the reliability of control, leave a margin in the background, namely The adjustable range of actual valve opening is 47-53.
[0054] 3. Start to automatically run the entire automatic control system, and monitor the color depth of the reactants in the distillation tower in real time through visual recognition methods to determine whether the current color depth of the reactants is within the optimal color depth range. If the color depth of the current reactant deviates from the 30-38 interval, adjust the opening of the control valve within the range of 48-52 to restore the current reactant color to the optimal color depth interval.
[0055] For example, when the color value leaves the optimal range of 30-38, for example, the value is 29. At this time, the opening of the touch valve decreases by 0.5. After stable operation for 20 seconds, the control will stop after returning to the optimal range of 30-38. Otherwise, Continue to adjust; if there is a situation where the field color is far from the optimal range of 30-38: For example, the value is 10, the valve is not adjusted violently, but increases from 0.5, first increases by 0.5, stabilizes for 20 seconds, then increases by 0.5, stabilizes by 20 Second, increase by 1 (the maximum adjustment amount is 1) until it returns to the optimal range of 30-38.
[0056] 4. In principle, when the color value is within the range of 30-38, there is no need to adjust the valve opening, but in this embodiment, a predictive function is set. When the color value is always increasing, we think that the chlorine is in an excessive trend. Automatically adjust the chlorine valve in a small range, such as reducing the valve opening by 0.5 each time, until this trend is eliminated.
[0057] Each time the valve opening is adjusted, the various parameters at that moment will be recorded for reference for subsequent adjustments. Such as image 3 As shown, at the next moment (10s before and after the time interval), the color changes from dark to light, indicating that the valve opening effect has taken effect, and the color depth value has an upward trend (a rising threshold can also be set, below the threshold can only be regarded as Fluctuations), but did not reach the upper limit reference value. At this time, the value of "parameter 1" will be referred to, and the adjustment value of the valve opening at this time will be given (it may be a closing trend). The specific adjustment value and adjustment direction can be established in advance based on the manual operation record data to establish the valve opening adjustment rule as an internal database for reference. Due to the hysteresis of the reaction process, this method can be used to make a judgment in advance to make the reaction enter the relative equilibrium stage, that is, the stage in which the reaction can always proceed within the optimal conditions without the valve action. of course, image 3 It only shows the process of determining the trend at two monitoring moments. In fact, more monitoring time points can be set.
[0058] The pre-judgment function is to eliminate the lag caused by the drastic color change and the drastic control of the valve, while stabilizing the valve opening in a reasonable range to ensure stable product quality.
[0059] In this embodiment, after the control system runs, the use effects are as follows:
[0060] 1. Eliminate the influence of human factors. Different people have individual differences in color judgment, especially at night, which will seriously affect the artificial judgment of color, and it is easy to cause fatigue and delay timely operation, resulting in improper addition of chlorine.
[0061] 2. After the operation of the automated system, the timeliness and accuracy of the amount of chlorine added are guaranteed, and from the aspect of bromine quality, this method stabilizes the chloride content of the product within 0.05%, meeting the requirements of GB/T2021-1991, from the extraction rate On the one hand, the bromine content of the distillation waste was reduced, and the bromine content in the waste was stabilized within 0.2 kg per cubic meter of discharged liquid.
[0062] 3. It greatly reduces the labor intensity of the operators, reduces the valve regulators at the distillation posts, and saves labor costs.
[0063] 4. It meets the requirements of safety and environmental protection, and realizes the separation of personnel from the site to ensure production safety, while reducing chlorine emissions.
