Virtual continuous emission monitoring system with sensor validation
DCFirst Claim
1. A method for monitoring emissions in a manufacturing plant that are generated as a by-product of the operation of the plant, the manufacturing plant having controls operating in response to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising the steps of:
- measuring on a periodic basis the level of pollutants emitted by the plant;
measuring the control values to the plant and the sensor values;
storing a representation of the plant in a virtual sensor predictive network having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the control values of the plant and the sensor values of the plant comprising inputs to the virtual sensor predictive network, the stored representation learned from the measured pollutant level, the control values and the sensor values, the virtual sensor predictive network operable to be trained upon the measured level of pollutants, the measured control values and the sensor values to generate the stored representation;
generating an error when the difference between the measured level of pollutants and the predicted pollutant level exceeds a predetermined threshold;
retraining the virtual sensor predictive network upon the generation of an error; and
controlling the plant utilizing the predicted pollutant level in accordance with a predetermined control scheme to vary the control values.
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Accused Products
Abstract
A continuous emission monitoring system for a manufacturing plant (10) includes a control system (16) which has associated therewith a virtual sensor network (18). The network (18) is a predictive network that receives as inputs both control values to the plant (10) and also sensor values. The network (18) is then operable to map the inputs through a stored representation of the plant (10) to output a predicted pollutant sensor level. This predicted pollutant sensor level is essentially the prediction of an actual pollutant sensor level that can be measured by a pollutant sensor (14). The network (18) therefore is a substitute for the pollutant sensor (14), thus providing a virtual sensor. The sensor values from the plant (10) are first processed through a sensor validation system (22). The sensor validation system (22) is operable to determine which of the sensors falls outside of acceptable limits and then substitutes therefor a predicted output, such that the inputs to the virtual sensor network (18) are within acceptable limits.
527 Citations
86 Claims
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1. A method for monitoring emissions in a manufacturing plant that are generated as a by-product of the operation of the plant, the manufacturing plant having controls operating in response to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising the steps of:
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measuring on a periodic basis the level of pollutants emitted by the plant; measuring the control values to the plant and the sensor values; storing a representation of the plant in a virtual sensor predictive network having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the control values of the plant and the sensor values of the plant comprising inputs to the virtual sensor predictive network, the stored representation learned from the measured pollutant level, the control values and the sensor values, the virtual sensor predictive network operable to be trained upon the measured level of pollutants, the measured control values and the sensor values to generate the stored representation; generating an error when the difference between the measured level of pollutants and the predicted pollutant level exceeds a predetermined threshold; retraining the virtual sensor predictive network upon the generation of an error; and controlling the plant utilizing the predicted pollutant level in accordance with a predetermined control scheme to vary the control values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for monitoring emissions in a manufacturing plant that is operable to generate pollutants, the manufacturing plant having controls operating in response to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising the steps of:
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storing a representation of the plant in a virtual sensor predictive network having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the control values of the plant and the sensor values of the plant comprising inputs to the virtual sensor predictive network, the stored representation learned from the measured pollutant level, the control values and the sensor values; determining if the sensor values for any of the sensors are outside of acceptable limits in accordance with predetermined criteria, which predetermined criteria is defined for each of the sensors; and substituting a known value for the sensor values of the ones of the sensors having sensor values determined to be outside of the acceptable limits by predicting from a past history of the sensor value to be substituted, a predicted sensor value for that sensor value, the predicted sensor value comprising the known value. - View Dependent Claims (14, 15, 16)
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17. A system for monitoring emissions in a manufacturing plant that are generated as a by-product of the operation of the plant, the manufacturing plant having controls operating in response to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising:
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a pollutant sensor for measuring on a periodic basis the level of pollutants emitted by the plant; a plant information system for measuring the control values to the plant and the sensor values of the plant; a virtual sensor predictive network for storing a representation of the plant and having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the control values of the plant and the sensor values of the plant from said plant information system comprising inputs to said virtual sensor predictive network, the stored representation learned from the measured pollutant level, the control values and the sensor values, said virtual sensor predictive network operable to be trained upon the measured level of pollutants, the measured control values and the sensor values to generate the stored representation; said pollutant sensor operable to compare the measured level of pollutants with the predicted pollutant level output by said virtual sensor predictive network and generate an error when the difference between the measured level of pollutants and the predicted pollutant level exceeds a predetermined threshold; a training system for retraining said virtual sensor network upon the generation of an error; and a controller for controlling the plant utilizing the predicted pollutant level output by said virtual sensor predictive network in accordance with a predetermined control scheme to vary the control values. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A system for monitoring emissions in a manufacturing plant that is operable to generate pollutants, the manufacturing plant having controls operating in response to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising:
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a virtual sensor predictive network for storing a representation of the plant and having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the control values to the plant and the sensor values of the plant comprising inputs to said virtual sensor predictive network, the stored representation learned from the measured pollutant level, the control values and the sensor values; a sensor validation system for determining if select ones of the sensor values associated with select ones of the sensors are outside of acceptable limits in accordance with predetermined criteria; and a substitute sensor for substituting a known value for the select sensor values when it is determined that they are outside of the acceptable limits, said substitute sensor comprising a predictive network for generating a predicted value for the one of the select sensor values determined to be outside of the acceptable limits, said predictive network generating said predicted value from a past history of the select sensor value to be substituted, said predicted value comprising said known value. - View Dependent Claims (29, 30, 31)
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32. A method for monitoring emissions in a manufacturing plant that are generated as a by-product of the operation of the plant, the manufacturing plant having controls operating in response to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising the steps of:
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measuring the level of pollutants emitted by the plant as a function of time; measuring the control values to the plant and the sensor values as a function of time, the measured level of pollutants and the measured control values and sensor values providing a training dataset; storing a representation of the plant in a virtual sensor predictive network having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the control values of the plant and the sensor values of the plant comprising inputs to the virtual sensor predictive network, the stored representation learned by training the virtual sensor predictive network on the training dataset; and controlling the plant utilizing the predicted pollutant level in accordance with a predetermined control scheme to vary the control values. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. A method for monitoring emissions in a manufacturing plant that are generated as a by-product of the operation of the plant, the manufacturing plant having controls operating in response to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising the steps of:
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measuring the level of pollutants emitted by the plant; measuring the control values to the plant and the sensor values; storing a representation of the plant in a virtual sensor neural network having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant by the steps of; providing an input layer and inputting to the input layer the control values and the sensor values, providing an output layer that is operable to output at least the predicted pollutant level, and providing at least one hidden layer and storing the representation of the plant in the hidden layer and mapping the input layer to the output layer through the stored representation in the at least one hidden layer; the control values of the plant and the sensor values of the plant comprising inputs to the input layer of the virtual sensor neural network, the stored representation learned from the measured pollutant level, the control values and the sensor values; and controlling the plant utilizing the predicted pollutant level in accordance with a predetermined control scheme to vary the control values. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57)
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58. A method for monitoring emissions in a manufacturing plant that is operable to generate pollutants, the manufacturing plant having controls operating in response to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising the steps of:
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storing a representation of the plant in a virtual sensor predictive network having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the control values of the plant and the sensor values of the plant comprising inputs to the virtual sensor predictive network, the stored representation learned from the measured pollutant level, the control values and the sensor values; providing a sensor validation predictive network having as an input the actual sensor values of the plant, the sensor validation predictive network having associated therewith a stored representation of each of the actual sensor values as a function of the other of the actual sensor values to provide on the output thereof a predicted sensor value for each of the actual sensor values input thereto; predicting with the sensor validation predictive network the predicted sensor values; determining the difference between the input sensor values for each of the sensors and the associated predicted sensor values; comparing the difference determined for each of the sensors with predetermined limits associated with each of the sensors for that difference; and substituting a known value for the sensor values of each of the sensors wherein the determined difference exceeds the predetermined limits. - View Dependent Claims (59, 60, 61)
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62. A system for monitoring emissions in a manufacturing plant that are generated as a by-product of the operation of the plant, the manufacturing plant having controls operating in response to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising:
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a pollutant sensor for measuring the level of pollutants emitted by the plant; a plant information system for measuring only select ones of the control values to the plant and select ones of the sensor values of the plant; a virtual sensor predictive network for storing a representation of the plant and having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the select ones of the control values to the plant and the select ones of the sensor values of the plant from said plant information system comprising inputs to said virtual sensor predictive network, wherein only the ones of the control values to the plant and the ones of the sensor values from the plant that substantially affect the predicted pollutant level output of said virtual sensor predictive network are selected by said plant information system, the stored representation learned from the measured pollutant level, the control values and the sensor values; and a controller for controlling the plant utilizing the predicted pollutant level output by said virtual sensor predictive network in accordance with a predetermined control scheme to vary the control values. - View Dependent Claims (63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73)
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74. A system for monitoring emissions in a manufacturing plant that are generated as a by-product of the operation of the plant, the manufacturing plant having controls responsive to received control values to alter the operation of the plant and sensors to measure the operating parameters of the plant and output associated sensor values, comprising:
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a pollutant sensor for measuring the level of pollutants emitted by the plant; a plant information system for measuring the control values to the plant and the sensor values of the plant; a virtual sensor neural network for storing a representation of the plant and having; an input layer for receiving as inputs the control values and the sensor values, an output layer that is operable to output at least a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the stored representation learned from the measured pollutant level, the control values and the sensor values, and at least one hidden layer for storing the representation of the plant therein and mapping said input layer to said output layer through the stored representation in said at least one hidden layer; and a controller for controlling the plant utilizing the predicted pollutant level output by said virtual sensor neural network in accordance with a predetermined control scheme to vary the control values. - View Dependent Claims (75, 76, 77, 78, 79, 80, 81, 82, 83, 84)
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85. A system for monitoring emissions in a manufacturing plant that is operable to generate pollutants, the manufacturing plant having controls responsive to control values to alter the operation of the plant and sensors outputting sensor values as a measure the operating parameters of the plant, comprising:
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a virtual sensor predictive network for storing a representation of the plant and having as an output a predicted pollutant level that corresponds to the actual pollutant level output by the manufacturing plant, the control values of the plant and the sensor values of the plant comprising inputs to said virtual sensor predictive network, the stored representation learned from the measured pollutant level, the control values and the sensor values; a sensor validation predictive network having as an input select ones of the actual sensor values of the plant and actual control values of the plant, said sensor validation predictive network having associated therewith a stored representation of each of the select actual sensor values and actual control values as a function of the other of the input actual sensor and control values to provide on the output thereof a predicted value for each of the actual sensor and control values input thereto; and a comparator for comparing each of the differences of the input actual sensor values and the predicted sensor values with predetermined limits for those differences to determine if select ones of the sensor and control values are outside of those predetermined limits; and a substitute sensor for substituting a known value for the select sensor or control values when it is determined that they are outside of the predetermined limits. - View Dependent Claims (86)
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Specification