Method and system for detecting and monitoring emissions

Abstract

A method and system for detecting, quantifying or characterizing emitting sources. According to an embodiment, an emission source is located by monitoring an area with one or more sensors, determining a plume, generating one or more candidates for the emission source, and using the plume to derive one or more characteristics associated with the emission source, and then locating the emission source based on agreement or convergence of the one or more characteristics.

1 . A method of characterizing a source of an emitted material in a flowing fluid, said method comprising the steps of:
 measuring concentrations of the emitted material in the flowing fluid at at least two or more locations at at least two times;   measuring changes in fluid flow velocity, being speed and direction of fluid flow, relevant to the concentration measurements over a relevant time;   performing spatial temporal analysis of said concentration measurements with reference to corresponding relevant velocity measurement, and thereby generating a dimensionless plume for each concentration measurement location in space;   generating a fluid flow trajectory based on said measured velocity changes and said measured concentrations for each concentration measurement location;   generating a plume trajectory for each generated dimensionless plume based on said measured fluid velocity changes and said measured concentrations for each generated dimensionless plum at each location;   correlating each such plume trajectory with each such dimensionless plume for locations each such dimensionless plume is projected to have been at a plurality of points in time during the relevant times;   projecting back along each such trajectory and correlating predicted emission source points along each such trajectory and proposing candidate source locations for the emission of the emitted material, each candidate being associated with plume size characteristics;   converting each dimensionless plume into a dimensioned plume at the relevant concentration location and determining a size characteristic based on said dimensioned plume;   compiling a listing of candidate source locations along such trajectories, and by comparison of concentration and characteristic plume size information associated with each such candidate source location with information associated with other candidate source locations, deriving a best-fit candidate source location or locations for each proposed emission source location; and   determining the source of the emitted material based on substantial agreement between the location and the characteristics of said first and second emission source candidates.   
     
     
         2 . The method of  claim 1 , wherein the characteristics associated with said emission source candidates include one or more of emission rate variability, horizontal emission location, vertical emission location, emission exit momentum, emission buoyancy, point emission source, area emission source, multiple emission sources, plume concentration profile for emission. 
     
     
         3 . The method of  claim 1 , wherein the at least two or more locations comprise a sensor stationed at a first location and then a second location. 
     
     
         4 . The method of  claim 1 , wherein the representative wind velocity comprises the velocity of wind flowing from the emission source to the measurement locations. 
     
     
         5 . The method of  claim 1 , wherein the step of determining a size characteristic based on said dimensioned plume comprises determining a flux within the dimensioned plume and background flux level, and subtracting the background flux from the flux within said dimensioned plume, and multiplying the flux difference with an area measurement of said dimensioned plume. 
     
     
         6 . The method of  claim 2 , wherein the step of determining a size characteristic comprises determining the emission rate variability, and said emission rate variability is determined by comparing one or more concentrations measured within said dimensioned plume to an average concentration measurement and the emission rate variability comprising deviations from the average concentration measurement. 
     
     
         7 . A computer readable data storage medium configured to store computer readable instructions executable by a computing device to cause the device to implement the steps of the method of  claim 1 . 
     
     
         8 . A method of characterizing a source of an emitted material, said method comprising:
 saving to a data store sensor data comprising information about the concentration of the emitted material in a flowing fluid at a particular time and a particular location, the sensor data having been collected from a plurality of locations at one or more times   saving to a data store information about the velocity of the flowing fluid, being its speed and direction at points in time and space, the information being in respect of a plurality of times and locations, said velocity-information-related times being proximate to the times of the emitted-material-concentration-information and the velocity-information-related locations being relevant to the sensor location of any source in the sense that the fluid containing the measured concentrations of emitted material had been affected by the fluid velocity being saved   using a dimensionless plume generating unit, generating a series of dimensionless plumes in space for each sensor location over time using the sensor data and the fluid velocity data as inputs to the dimensionless plume generating unit   using a trajectory generating unit, correlating the generated dimensionless plume location series for each sensor location from the dimensionless plume generating unit with fluid velocity information from the data store by reference to time in order to generate a trajectory for each plume in such series of generated plumes   using a modeling unit, using the plume trajectories from the trajectory generating unit and the generated series of dimensionless plumes from the dimensionless plume generating unit as inputs to a model for projecting a modeled plume back along its trajectory in a calculated direction of its probable source, calculating a predicted candidate location for an emission source location and at least one further emission source location characteristic for each dimensionless plume   using a plume conversion unit, converting each series of dimensionless plumes for each sensor location to one or more dimensioned plumes at such location at one or more relevant particular times
 using the dimensions of the dimensioned plume at each sensor location at each particular time to determine a plume size characteristic relevant to the emission source location predicted by operation of the modeling unit 
 using the dimensions of the dimensioned plume at each sensor location at each particular time to determine a plume size variability characteristic over time relevant to the emission source location predicted by operation of the modeling unit; and 
   in a comparator unit, matching and comparing the plume size variability characteristics relevant to each emission source location predicted for each sensor location to reduce the candidate predicted emission source locations to those which most closely match, the comparator unit scoring potential sources location based on: horizontal location, size or emission rate, size or emission rate variability, and vertical.   
     
     
         9 . The method of  claim 8 , wherein said plume size variability characteristics associated with said emission source candidates include one or more of emission rate variability, horizontal emission location, vertical emission location, emission exit momentum, emission buoyancy, point emission source, area emission source, multiple emission sources, plume concentration profile for emission. 
     
     
         10 . The method of  claim 8 , wherein the plurality of concentration measurements are made by a sensor stationed at a first location and then a second location. 
     
     
         11 . The method of  claim 8 , wherein said representative wind velocity information comprises information about the velocity of wind flowing somewhere between the emission source toward the measurement locations during a relevant time. 
     
     
         12 . The method of  claim 8 , wherein said step of determining a size characteristic based on said dimensioned plume comprises determining a flux within the dimensioned plume and background flux level, and subtracting the background flux from the flux within said dimensioned plume, and multiplying the flux difference with an area measurement of said dimensioned plume. 
     
     
         13 . The method of  claim 9 , wherein said step of determining a size characteristic comprises determining the emission rate variability, and said emission rate variability is determined by comparing one or more concentrations measured within said dimensioned plume to an average concentration measurement and the emission rate variability comprising deviations from the average concentration measurement.