System and method for improved flow data reconciliation
First Claim
1. A computer-based method of processing flow signals, said method employing data reconciliation, comprising the steps of:
- (1) operating a process comprising one or more units and two or more streams to produce a product;
(2) measuring flow rates and temperatures of two or more of said streams to produce raw flow signals;
(3) predicting, using dynamic simulation, predicted flow signals for one or more of said streams not measured in step (2);
(4) constructing a complete mass balance around at least one of said units, by using said raw flow signals and said predicted flow signals;
(5) correcting one or more of said raw flow signals and/or predicted flow signals by using said complete mass balance to produce mass corrected flow signals; and
(6) directly or indirectly changing the state of a final control element of said process in response to said mass corrected flow signals in accordance with an operating objective.
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention is a system and method for improved processing of flow data signals to provide output flow data signals which better approximate the true flows being measured. The general approach on which the invention is based is commonly known as flow data reconciliation. A dynamic simulation is run in parallel with a flow data reconciliation, and model predicted flows are used to complete balances wherever sensor measurements are unavailable. Model predicted compositions are also used to allow the computation of stream enthalpies so that enthalpy balances can be used in the reconciliation. The use of model predicted values of changes in inventory allow dynamic material balances to be used, making the reconciliation much more effective for processes with slow dynamic behavior. Weighting factors on sensors, computed based on the current value of the error of the sensor, reduce the impact of sensors with high errors. A multiplicative correction factor distributes corrections more evenly among streams with large and small flows. Statistical behavior of historical performance of sensors is used to reduce the adverse impact of rapid shifts in sensor accuracy and to detect unconverged reconciliation solutions.
-
Citations
15 Claims
-
1. A computer-based method of processing flow signals, said method employing data reconciliation, comprising the steps of:
-
(1) operating a process comprising one or more units and two or more streams to produce a product; (2) measuring flow rates and temperatures of two or more of said streams to produce raw flow signals; (3) predicting, using dynamic simulation, predicted flow signals for one or more of said streams not measured in step (2); (4) constructing a complete mass balance around at least one of said units, by using said raw flow signals and said predicted flow signals; (5) correcting one or more of said raw flow signals and/or predicted flow signals by using said complete mass balance to produce mass corrected flow signals; and (6) directly or indirectly changing the state of a final control element of said process in response to said mass corrected flow signals in accordance with an operating objective. - View Dependent Claims (2, 3, 4)
-
-
5. A computer-based data reconciliation system, comprising:
-
(a) two or more sensors for producing raw flow signals indicative of flow rates of two or more streams in a process comprising one or more units and two or more streams; (b) a computer-based dynamic simulation, connected to use mass corrected flow signals and said raw flow signals as inputs, for producing predicted flow signals for one or more of said streams; and (c) a computer-based flow data reconciliation module, connected to use said predicted flow signals and said raw flow signals as inputs, for correcting said raw flow signals to minimize a mass error sum of a complete mass balance around at least one of said one or more units, to produce said mass corrected flow signals. - View Dependent Claims (6, 7, 8, 9)
-
-
10. A computer-based method of processing flow signals, said method employing data reconciliation, comprising the steps of:
-
(1) operating a process comprising one or more units and two or more streams to produce a product; (2) measuring flow rates of two or more of said streams to produce raw flow signals; (3) constructing a complete mass balance around at least one of said units, using said raw flow signals; (4) adjusting each of said raw flow signals by multiplying each signal by a respective constant; and (5) adjusting said respective constants to minimize a sum of values, each value indicative of the deviation of each said respective constant from a value of one. - View Dependent Claims (11, 12)
-
-
13. A computer-based data reconciliation system, comprising:
-
(a) two or more sensors for producing raw flow signals indicative of flow rates of two or more streams in a process comprising one or more units; (b) a computer-based flow data reconciliation module, connected to use said raw flow signals as inputs, for correcting said raw flow signals to produce mass corrected flow signals by multiplying each signal by a respective constant and adjusting said respective constants to minimize a sum of values, each value indicative of the deviation of each said respective constant from a value of one. - View Dependent Claims (14, 15)
-
Specification