Spray drying plant operator training system

Abstract

A method for training an operator of a spray drying plant, the spray drying plant including a plurality of plant elements including pre-processing elements, a spray drying element, post-processing elements, powder recovery elements, and a programmable logic controller, PLC. The method including the steps of: obtaining a transient model of the spray drying plant, wherein the transient model includes transient sub-models of the plurality of plant elements; calculating repeatedly simulated sensor data based on the obtained transient model, using a processing unit; displaying on a display a training human machine interface, tHMI, configured to communicate with the transient model of the spray drying plant, and to display the simulated sensor data and control data for the transient model; and updating the transient model based on operator input on the tHMI, for controlling the transient model of the spray drying plant.

Claims

1-16. (canceled)

17. A method for training an operator of a spray drying plant, the spray drying plant comprising a plurality of plant elements including pre-processing elements, a spray drying element, post-processing elements, powder recovery elements, a programmable logic controller, PLC, a plurality of sensors, and a plurality of active elements, wherein the plurality of sensors are configured to measure process variables on the plurality of plant elements and to send sensor signals to the PLC, and wherein the plurality of active elements are configured to control process variables of one or more of the plurality of plant elements in response to control signals received from the PLC, the spray drying plant further comprising an operation human machine interface, oHMI, configured to communicate with the PLC and to display a plurality of sensor data based on obtained sensor signals from the plurality of sensors; the method comprising the steps of: obtaining a transient model of the spray drying plant, wherein the transient model comprises transient sub-models of the plurality of plant elements; calculating repeatedly simulated sensor data based on the obtained transient model, using a processing unit; displaying on a display a training human machine interface, tHMI, configured to communicate with the transient model of the spray drying plant, and to display the simulated sensor data and control data for the transient model; and updating the transient model based on operator input on the tHMI, for controlling the transient model of the spray drying plant.

18. The method according to claim 17, wherein the transient sub-model for the spray drying chamber is based on one or more inputs and one or more outputs, where the one or more inputs and one or more outputs comprise one or more of the following: the mass flow, the temperature, and the vapor fraction of the air going into the spray drying chamber, or the mass flow, the temperature, and the solids fractions in a product to be dried.

19. The method according to claim 17, wherein the transient sub-model for the spray drying chamber comprises the modelling of at least one of the following: the volume of the spray drying chamber, the heat loss through the surface area of the spray drying chamber, the thickness of the walls of the spray drying chamber, the heat capacity of the walls of the spray drying chamber, the heat transfer coefficient from air to walls, the heat transfer coefficient of the product to be spray dried, the evaporation efficiency of the product to be spray dried, and the fraction of fine particles of the product to be spray dried.

20. The method according to claim 17, wherein at least a portion of the tHMI visual layout is identical to the oHMI.

21. The method according to claim 17, wherein the spray drying plant further comprises an operator control room having a workstation with a display, the workstation having an operation mode and a training mode, wherein the workstation is configured to display on the display the oHMI in the operation mode and the tHMI in the training mode.

22. The method according to claim 21, wherein when the workstation is in the training mode, a control unit repeatedly evaluates whether the spray drying plant is in a steady state, and if said control unit determines that the steady state conditions are not fulfilled the control unit performs an action to switch the workstation from the training mode to the operation mode.

23. The method according to claim 21, wherein the processing unit is configured to set initial condition for the transient model based on sensor data received from the spray drying plant.

24. The method according to claim 17, further comprising the steps of: providing the processing unit with a pre-programmed fail scenario; and modifying the transient model based on the pre-programmed fail scenario using the processing unit.

25. The method according to claim 24, further comprising the steps of: providing the processing unit with best practice criteria related to a first pre-programmed scenario; and evaluating using the processing unit a performance of the operator based on the best practice criteria.

26. The method according to claim 24, wherein the transient model is configured to communicate with a transient model human machine interface, tmHMI, where the tmHMI is configured to control the transient model by setting initial condition for the transient model and/or activating a particular pre-programmed fail scenario of a plurality of pre-programmed fail scenarios.

27. The method according to claim 17, further comprising the step of: displaying an operator interface allowing the operator to input auxiliary operator actions.

28. The method according to claim 27, wherein the transient model is further updated based on operator input on the operator interface.

29. The method according to claim 28, wherein the transient sub-models of the plurality of plant elements comprises a first transient sub-model, modelling a first plant element in a first state and wherein the step of updating the transient model based on operator input on the operator interface comprises substituting the first transient sub-model with a second transient sub-model modelling the first plant element in a second state.

30. The method according to claim 27, wherein the operator interface is configured to allow an operator to indicate a plant element of the plurality of plant elements and an auxiliary action.

31. The method according to claim 27, wherein the method further comprises the steps of: providing the processing unit with a pre-programmed fail scenario, simulating failure of a plant element of the plurality of plant elements; providing the processing unit with best practice criteria related to the pre-programmed fail scenario; modifying the transient model based of the pre-programmed fail scenario by substituting a transient sub-model modelling the plant element that is to be failing with another transient sub-model simulating the failure; and evaluating using the processing unit a performance of the operator based on the best practice criteria, wherein the best practice criteria include specific one or more auxiliary operator actions to be performed by the operator using the operator interface.

32. The method according to claim 31, wherein the specific one or more auxiliary actions simulate a maintenance operation or a substitution operation on the failing plant element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The above and/or additional objects, features and advantages of the present invention will be further elucidated by the following illustrative and non-limiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein:

[0065] FIG. 1 shows a block diagram representing an example of a method for training an operator of a spray drying plant, according to an embodiment of the invention.

[0066] FIG. 2 shows a flow chart of a method for training an operator of a spray drying plant.

[0067] FIG. 3 shows an example of an operator interface allowing the operator to input an auxiliary operator action.

[0068] FIG. 4 shows a schematic representation of a spray drying plant, according to an embodiment of the invention.

[0069] FIG. 5 shows a schematic drawing of a computer system implementing a method for training an operator of a spray drying plant, according to an embodiment of the invention.

DETAILED DESCRIPTION

[0070] In the following description reference is made to the accompanying figures, which show by way of illustration how the invention may be practiced.

[0071] FIG. 1 shows a block diagram representing an example of a method for training an operator of a spray drying plant, according to an embodiment of the invention, where the spray drying 170 plant comprises a plurality of plant elements including pre-processing elements, a spray drying element, post-processing elements, powder recovery elements, a programmable logic controller 150, PLC, a plurality of sensors, and a plurality of active elements, wherein the plurality of sensors are configured to measure process variables on the plurality of plant elements and to send sensor signals to the PLC 150, and wherein the plurality of active elements are configured to control process variables of one or more of the plurality of plant elements in response to control signals received from the PLC 150, the spray drying plant 170 further comprising an operation human machine interface 130, oHMI, configured to communicate with the PLC 150 and to display a plurality of sensor data based on the obtained sensor data from the plurality of sensors. The method further comprises the steps to obtaining a transient model of the spray drying plant 170, wherein the transient model comprises transient sub-models of the plurality of plant elements; calculating repeatedly simulated sensor data based on the obtained transient model, using a processing unit 140; displaying on a display a training human machine interface 120, tHMI, configured to communicate with the transient model of the spray drying plant 170, and to display the simulated sensor data and control data for the transient model; updating the transient model based on operator input on the tHMI 120, for controlling the transient model of the spray drying plant 170.

[0072] The PLC 150 is operatively connected to the spray drying plant 170 and thereby to one or more of the plurality of sensors and active elements. The PLC 150 may be located at the spray drying plant 170 or may alternatively be located remotely from the spray drying plant 170 and in communication with the plurality of sensors and active elements. The PLC 150 is operatively connected to the oHMI 130. The spray drying plant 170 may receive control signals from the PLC which then may control one or more of the elements of the spray drying plant 170. The control signals may be pre-programmed in the PLC or may also be send from the oHMI, received at PLC, and then generated at the PLC.

[0073] The oHMI 130 may be comprised in a SCADA system installed on the workstation 160 in the control room of the spray drying plant 170. The SCADA system may acquire the sensor data and the control data from the PLC.

[0074] The processing unit 140 repeatedly i.e. continuously calculates simulated sensor data 140 in order to update the tHMI 120 with the most recently calculated simulated sensor data.

[0075] The tHMI 120 is operatively connected to the processing unit 140 and displays a plurality of simulated sensor data and control data based on the obtained transient model.

[0076] In an alternative embodiment the tHMI 120 may be operatively connected to the PLC 150. The tHMI 120 and oHMI 130 may be on separate workstations 160 and therefore displayed on separate displays. The oHMI 130 may e.g. be displayed on a workstation 160 in a control room at the spray drying plant 170.

[0077] The tHMI 120 may also be displayed on a display of a workstation 160 in a control room at the spray drying plant 170 but may also be displayed on a display of a separate workstation in a separate training room. The processing unit 140 may be comprised in a common workstation 160 for the oHMI 130 and the tHMI 120 and update the transient model which is stored at the common workstation 160. Alternatively, a separate processing unit 140 may be comprised e.g. remotely on a server and may update the transient model on the server and communicate with the workstation 160.

[0078] In an alternative embodiment, a control unit 110 is operatively coupled to the PLC 150, the workstation 160, and the processing unit 140. When the workstation 160 is in the training mode, the control unit 110 repeatedly evaluates whether the spray drying plant 170 is in a steady state, and if said control unit 110 determines that the steady state conditions are not fulfilled the control unit 110 performs an action to switch the workstation 160 from the training mode to the operation mode.

[0079] FIG. 2 shows a flow chart of a method for training an operator of a spray drying plant by having a control unit for switching between a training mode and an operation mode. When the workstation is in the training mode, a control unit repeatedly evaluates whether the spray drying plant is in a steady state, and if said control unit determines that the steady state conditions are not fulfilled the control unit performs an action to switch the workstation from the training mode to the operation mode. When the tHMI and the oHMI are running in a common control room or on a common workstation, an operator may thereby combine the supervision of the actual spray drying plant and the training on the simulated spray drying plant.

[0080] FIG. 3 shows an example of an operator interface 300 allowing the operator to perform an auxiliary operator action. When an operator is performing a training on the tHMI of the workstation, the operator may not always be able to solve a fail scenario by performing actions on the tHMI. Some real life fail scenarios may only be solved by taking action directly on the spray drying plant. This may be done by sending a person to the plant to solve the fail scenario, such as a plant technician or engineer, an electrician, a plumber, a fire worker etc. This may for training purposes be simulated in the tHMI by generating the operator interface 300 allowing e.g. to perform an auxiliary operator action such as calling a plant technician, an electrician, a plumber, a fireworker, or a supervisor of the spray drying plant. The actions that the operator can perform may be simulated in the form of buttons 310 that the operator can press with the mouse of the workstation such that the actions performed by the operator can be tracked and recorded. The operator may e.g. click on the button for simulating the action of calling a plant technician and then confirming by clicking the button for performing the auxiliary operator action.

[0081] FIG. 4 shows a schematic representation of a spray drying plant 400 for the spray drying of milk, comprising a milk buffer tank 410, a first centrifugal pump 420, an evaporator 430, a second centrifugal pump 440, a homogenizer 450, a spray dryer 460, a fluid bed 470, a cyclone 480, a bag-filter 490, and a powder silo 495. Here an example of a spray drying process is the spray drying of milk for making powdered milk. The liquid milk is stored in the milk buffer tank 410. Then the milk is first pre-processed for roughly removing the water content of the milk liquid with s first centrifugal pump 420 and a second centrifugal pump 440, an evaporator 430, and a homogenizer 450. Then the concentrated milk is spray dried by being pumped into a spray drying chamber 460, where it is sprayed out through atomizers such as high-pressure nozzles at the same time as a continuous stream of warm drying air is pumped into the chamber. This removes most of the water content from the drops of milk. As it is in most cases it is not possible to prevent the drying air from capturing a minor part of the dry matter content, the air undergoes a post-processing procedure through a cyclone 480 and bag-filter 490. The collected dry matter is then later returned to the process. Nevertheless, the majority of the dry matter content from the milk falls to the bottom of the chamber 460 as powdered milk. The powder is not left lying on the bottom of the chamber, as the bottom is a fluid bed 470. The powdered milk is then stored in the powder silo 495 until the silo is emptied.

[0082] FIG. 5 shows a schematic drawing of a computer system 500 implementing a method for training an operator of a spray drying plant, according to an embodiment of the invention. The computer system comprises a number of functional blocks, in particular a transient model functional block 501 simulating a real spray drying plant, a Simulated PLC 502 simulating a PLC of the real spray drying plant, a Database functional block 505 storing a plurality of pre-programmed failure scenarios, a training human machine interface, tHMI, functional block 503 configured to allow an operator to interact with the transient model functional block 501 and see simulated sensor data, and a transient model human machine interface, tmHMI, functional block 504. The tmHMI functional block is configured to allow a trainer to interact with the transient model 501 in order to set initial conditions for the transient model functional block 501 and/or activate pre-programmed failure scenarios stored in the Database functional block 505. By using a Simulated PLC functional block 502, the program code for the oHMI used at the real plant may directly be used for the tHMI, whereby the training may be more realistic. This will furthermore make it easy to change the tHMI if the oHMI is changed, i.e. by simply reusing the new program code of the changed oHMI. The different functional blocks may be implemented in different ways, as an example the Simulated PLC functional block 502, the Transient model functional block 501 and the Database functional block 505 may be implemented on a server 506, the tHMI functional block 503 may be implemented on a first workstation 507, and the tmHMI functional block 504 may be implemented on a second workstation 508. However, the Simulated PLC functional block 502, the Transient model functional block 501 and the Database functional block 505 may also be implemented on two or more servers or all functional blocks could even be implemented in a single workstation.

[0083] Although some embodiments have been described and shown in detail, the invention is not restricted to them, but may also be embodied in other ways within the scope of the subject matter defined in the following claims. In particular, it is to be understood that other embodiments may be utilised and structural and functional modifications may be made without departing from the scope of the present invention.

[0084] In device claims enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage.

[0085] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.