Spray drying plant operator training system

Abstract

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

Description

Technical Field

[0001] This invention relates to a training method and corresponding system for operators of spray drying equipment. Background Technology

[0002] Spray drying equipment is widely used in the food, dairy, feed, raw material, chemical processing, and pharmaceutical industries. Spray drying is a method of producing dry powder from liquids or slurries through rapid drying using hot or cold gas. For maximum efficiency, spray drying equipment typically operates continuously. Standard spray drying equipment includes numerous components, resulting in a fairly complex structure. Spray drying equipment consists of many components that can be combined in various ways to optimize the drying process for the specific product being dried. Components in spray drying equipment may include: pretreatment elements (including heating, concentration, mixing, homogenization, and evaporation) for pretreatment of liquid feeds; spray dryers (including air dispersers, atomizers, heaters, drying chambers, internal fluidized beds, fine particle recirculation, etc.); post-treatment elements (including fluidized beds, mixers, grinders, rewetting, and agglomeration) for post-processing dried or semi-dried powders; and powder recovery elements (bag filters, cyclone dust collectors, and combinations thereof).

[0003] To ensure proper equipment operation, operators typically monitor the spray drying process from a workstation during operation. To achieve this, spray drying equipment is usually equipped with multiple sensors that measure various parameters on different equipment components, as well as multiple active components that can control these parameters. These sensors and active components are then connected to a programmable logic controller (PLC), which in turn communicates with a workstation equipped with a Supervisory Control and Data Acquisition (SCADA) system and a Human-Machine Interface (HMI) to display the data from the sensors and active components. This allows the equipment operator to understand the overall equipment status, and if parameters exceed threshold ranges or if one or more equipment components malfunction, the operator can receive alarms or visual notifications on the HMI, enabling them to take action to correct the error or stop the spray drying process.

[0004] Even though equipment operators can correct equipment malfunctions in many cases, there are times when operators are either too slow to react or unprepared for the malfunctions that are occurring. This is often because operators, even the most experienced ones, do not encounter some rare malfunctions that are critical to the equipment in their daily operations. Some malfunctions can cause irreversible damage to spray drying equipment, and the expensive machinery may be damaged. These damaged equipment components must then be replaced or repaired, which is expensive in itself, and the equipment may also suffer prolonged downtime. This is critical for suppliers and distributors who rely on the functionality of spray drying equipment.

[0005] For example, in the milk spray drying industry, milk suppliers may be unable to unload trucks full of milk due to downtime. Training operators of specific drying equipment takes time, and high automation leads to a lack of practical experience in handling different failure scenarios. Operators may need many years to master complex control systems, and extensive supervision by more experienced operators is required. Another problem is that many operators lack confidence when faced with actual problems with operating equipment. Because many pieces of equipment, as mentioned above, cannot be stopped for training purposes, some operators have never encountered a failure situation before it actually occurs. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a method for training operators of spray drying equipment to overcome one or more of the problems mentioned above.

[0007] According to a first aspect of the invention, these and further objectives can be achieved by a method for training an operator of a spray drying equipment, the spray drying equipment comprising a plurality of equipment elements, including a pretreatment element, a spray drying element, a post-treatment element, a powder recovery element, 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 equipment elements and transmit sensor signals to the PLC, and wherein the plurality of active elements are configured to control the process variables of one or more of the plurality of equipment elements in response to control signals received from the PLC, the spray drying equipment further comprising an operator human-machine interface (oHMI) configured to communicate with the PLC and display a plurality of sensor data based on sensor signals obtained from the plurality of sensors; the method comprising the following steps:

[0008] • Obtain the instantaneous mode of the spray drying equipment, wherein the instantaneous mode includes instantaneous sub-modes of multiple equipment components;

[0009] • Based on the obtained instantaneous patterns, the processing unit repeatedly calculates the simulated sensor data;

[0010] • Display a training human-machine interface (tHMI) on the monitor, which is configured to communicate with the instantaneous mode of the spray drying equipment and display analog sensor data and control data of the instantaneous mode;

[0011] • Update the instantaneous mode based on operator input on the tHMI to control the instantaneous mode of the spray drying equipment.

[0012] By utilizing the method according to the first aspect of the invention, a realistic simulation mode of spray drying equipment can be achieved. Using the training method described above, the equipment operator will receive equipment simulation training substantially the same as the equipment the operator will be operating. Therefore, operators receiving such simulated HMI training can be prepared for failure scenarios substantially similar to those in reality. This can lead to improved training for equipment operators. tHMI can be used to train newly hired operators, new operators of the equipment, and experienced operators who must ensure real-time understanding of certain aspects, such as those related to a given spray drying equipment, certain failure procedures, or maintenance procedures. Even experienced operators who have encountered many different failure scenarios in their daily work should still be able to react quickly to, for example, failure scenarios to avoid damaging the equipment. Some failure scenarios may be very rare, and even highly experienced operators may only encounter such scenarios a few times during their daily work, or even never encounter them in some cases. Therefore, operators can receive proactive, regular training instead of traveling to, for example, specialized training facilities for multi-day training courses (e.g., the entire training course).

[0013] A further advantage of the above method is its flexibility in adapting to changes in the spray drying equipment, such as the replacement, removal, or introduction of new equipment components. Therefore, operators to be trained can receive training on substantially the latest tHMI information relative to the actual equipment.

[0014] An example of a spray drying process is milk spray drying used to manufacture milk powder. First, the milk is pretreated to substantially remove the water content from the liquid milk, for example, using one or more centrifugal pumps, evaporators, and homogenizers. The concentrated milk is then pumped into a spray drying chamber for spray drying, where it is atomized through atomizers such as high-pressure nozzles while a continuous stream of warm, dry air is pumped into the chamber. This removes most of the water content from the milk droplets. Since it is generally impossible to prevent the drying air from capturing a small portion of the dry matter content, the air undergoes a post-treatment process, such as through a cyclone dust collector and a bag filter. The collected dry matter is then returned to the process. However, most of the dry matter content in the milk falls to the bottom of the spray drying chamber as milk powder. The powder does not remain at the bottom of the spray drying chamber because the bottom is covered by a gill-like slit cover such as a fluidized bed. Air is blown out in such a way that the air and powder mixture behaves in the same manner as a fluid. This is commonly referred to as "fluidization" in the spray drying field. Fluidization helps to transport the powder to one or more drying chambers, where the water content can be further reduced.

[0015] Spray drying equipment comprises multiple equipment components, including pretreatment elements, spray drying elements, post-treatment elements, powder recovery elements, a programmable logic controller (PLC), multiple sensors, and multiple active elements. The pretreatment elements may be, for example, heating elements, concentrator elements, mixer elements, homogenizing elements, or evaporators. The pretreatment elements are used to prepare the liquid to be spray-dried before spray drying. Preferably, the content of, for example, water in the liquid to be spray-dried is reduced before the start of the spray drying process, such that the dry matter content of the liquid is about 50%. This is because the spray drying process is more efficient when the dry matter content is higher, and pretreatment of the liquid to be spray-dried is more cost-effective than simply removing moisture by spray drying. After pretreatment, the liquid is directed to the spray drying element, which may, for example, include one or more spray drying chambers and one or more atomizers, such as high-pressure nozzles. The spray drying chamber is typically a large container made of stainless steel, in which air is blown at the top, and the liquid product to be treated is fed into the spray drying chamber and atomized into small droplets through the high-pressure nozzles contained within the spray drying chamber.

[0016] The PLC is operatively connected to one or more of a plurality of sensors and a plurality of active components. The PLC may be located at the spray drying equipment, or alternatively at a location remote from the equipment and communicating with the plurality of sensors and active components. This can be achieved via an input / output (I / O) interface located at the spray drying equipment. The disclosed PLC includes a computer and can be any unit including a unit capable of performing basic arithmetic, such as a central processing unit (CPU). The PLC may include one or more drivers for communicating with the plurality of sensors and active components. It may further include digital I / O interfaces and analog I / O interfaces. The PLC may be pre-programmed to perform logical operations, such as acquiring sensor signals and active component signals to send control signals to the sensors and active components. The PLC is operatively connected to an oHMI. This connection may be a direct wired connection, for example if the oHMI is located at the spray drying equipment, but may alternatively be a network connection such as the Internet, cloud, etc.

[0017] Sensors are located on one or more equipment elements to measure process variables on multiple equipment elements. For example, sensors are humidity sensors (i.e., hygrometers), temperature sensors, flow sensors, and pressure sensors, used to measure process variables such as humidity, temperature, flow rate, and pressure, respectively. Active elements can be included in one or more equipment elements to control the equipment element or as equipment elements themselves. Active elements can be configured to perform activities or actuate devices. For example, an active element can be a valve in an equipment element (e.g., a pump), a switch for switching between equipment elements (e.g., switching from a running pump to a redundant pump), or any other element for controlling process variables. In some cases, process variables may need to be controlled by more than one active element. For example, to control the powder output from a spray drying equipment, many process variables may need to be changed. This could be, for example, the milk input, the pressure of the atomizer, the temperature in the spray drying chamber, etc. Active elements can receive control signals from a PLC, which can then control the active element. The control signals can be pre-programmed in the PLC, or they can be sent from an OHMI, received at the PLC, and then generated at the PLC.

[0018] oHMI can generally be understood as a user interface or dashboard that allows a user or operator to interact with a machine, system, or device. HMI can also be alternatively referred to as a human-machine interface (MMI), operator interface terminal (OIT), local operator interface (LOI), or operator terminal (OT). oHMI can also include a graphical user interface (GUI) for, for example, visualizing the different components of a spray drying device.

[0019] The oHMI can be displayed on a computer in the control room of the spray drying equipment. The oHMI can also be included in a SCADA system installed on a workstation in the control room of the spray drying equipment. The SCADA system can acquire sensor data and control data from the PLC.

[0020] Transient models can be stored at the spray drying equipment or in the cloud, database, or other remote locations. A transient model comprises sub-models of multiple equipment elements. Sub-models are interdependent, meaning the equipment elements within a model are related to each other. The output of one sub-model can thus be the input of another sub-model, and the sum of one or more sub-models defines the transient model. For example, a sub-model of the spray drying chamber can be modeled based on specific inputs and outputs. Inputs can be air entering the spray drying chamber, such as mass flow rate, temperature, and vapor fraction; or the product entering the chamber, such as the product's mass flow rate, temperature, or solids fraction. Outputs from the spray drying chamber can be powder from the drying chamber and powder-related parameters (such as mass flow rate, moisture fraction, and temperature), and air exiting the spray drying chamber and air-related parameters (such as pressure, temperature, vapor fraction, and solids fraction).

[0021] One or more parameters can be modeled in the instantaneous mode and instantaneous sub-mode. For a spray drying chamber, the following parameters can be modeled, such as volume, heat loss through surface area, wall thickness, wall heat capacity, air-to-wall heat transfer coefficient, and powder technology-specific constants (e.g., time delay, heat transfer coefficient, evaporation efficiency, and fine particle fraction). These inputs and outputs, along with the associated parameters, can be defined in the sub-mode using a physical model. For example, some examples demonstrate mass balance achieved by integrating inflow flow rates minus outflow rates of air, solids, and water, calculating air pressure, calculating the mass flow rate of powder in the spray dryer, and calculating the water fraction, vapor fraction, and solid fraction in the powder; and thermal balance in the spray drying chamber achieved by modeling heat loss through the wall, wall temperature, air temperature, and powder temperature. The type of product processed during spray drying can influence the instantaneous sub-mode. Depending on the type of product being processed, the physical properties of the product may vary. Products are typically composed of mixtures of substances, each with specific properties such as heat capacity and density. Products can often be mixtures of water and solids, which can be described by the product mass flow rate and the solid fraction in the product. Therefore, the type of product being processed may affect the transient subpattern.

[0022] Control signals can be generated from operator input on the oHMI, such as changing process variables of one or more device elements. Control signals can be sent to multiple active elements. Sensor data can be process variables measured by multiple sensors.

[0023] Repeatedly compute (i.e., continuously compute) simulated sensor data in order to update the tHMI using the most recently computed simulated sensor data.

[0024] Analog sensor data can also be calculated based on control data, i.e., input from the operator. Therefore, the operator can obtain direct results or responses from the control data already input into the tHMI.

[0025] The tHMI is operatively connected to the processing unit and displays multiple analog sensor and control data based on the acquired instantaneous patterns. The tHMI can generally be understood as a user interface or dashboard that allows a user or operator to interact with the machine, system, or device. The tHMI may also include a graphical user interface (GUI) for, for example, visualizing different components of a spray drying equipment. The tHMI and oHMI can reside on different workstations and therefore be displayed on different monitors. For example, the oHMI may be displayed on a workstation in the control room of the spray drying equipment. The oHMI can be included in a SCADA system installed on a workstation in the control room of the spray drying equipment. The SCADA system can acquire sensor and control data from a PLC. The tHMI can be displayed on a monitor at a workstation in the control room of the spray drying equipment, but it can also be displayed on a monitor at a workstation in a different training room. The processing unit can be included in a common workstation used for both the oHMI and tHMI, and updates the instantaneous patterns stored at the common workstation. Alternatively, the processing unit can be included in a workstation used only for the tHMI, and updates the instantaneous patterns on that workstation. Alternatively, different processing units can be included, for example, remotely on a server, and can update the transient model on the server and communicate with the workstation. In another alternative, different processing units can be included, for example, remotely on a server, and can update the transient model stored at the workstation in the tHMI and communicate with the workstation.

[0026] In some implementations, the transient sub-mode of the spray drying chamber is based on one or more inputs and one or more outputs, wherein the one or more inputs and one or more outputs include one or more of the following: the mass flow rate, temperature, and vapor fraction of the air entering the spray drying chamber, or the mass flow rate, temperature, and solids fraction of the product to be dried.

[0027] In some implementations, the instantaneous sub-mode of the spray drying chamber includes modeling 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 spray drying chamber wall, the heat capacity of the spray drying chamber wall, the air-to-wall heat transfer coefficient, the heat transfer coefficient of the product to be spray dried, the evaporation efficiency of the product to be spray dried, and the fine particle fraction of the product to be spray dried.

[0028] In some implementations, at least a portion of the tHMI visual layout is identical to the oHMI. The visual layout of the tHMI can be substantially the same as that of the oHMI. This can be advantageous when the operator has already been trained on the tHMI, enabling the operator to recognize the visual layout of the oHMI when returning to the actual spray drying equipment and oHMI. This allows the operator to react more quickly to malfunctions. When actions are performed on the oHMI, the operator will also know how the oHMI will visually react.

[0029] In some embodiments, the spray drying equipment also includes an operator control room with a workstation equipped with a display having an operating mode and a training mode, wherein the workstation is configured to display an oHMI in operating mode and a tHMI in training mode on the display. The workstation may include a computer equipped with a display, mouse, and keyboard, enabling the operator to control the oHMI and tHMI. The workstation may include a computer for each of the oHMI and tHMI, such that the oHMI is displayed on one display and the tHMI on another display, or the oHMI and tHMI may be displayed on a common display. The oHMI and tHMI may be located in different operator control rooms at the spray drying equipment or at a remote location within the spray drying equipment. For example, the operating mode may be displayed on a computer in the operator control room at the spray drying equipment, while the training mode may be displayed on a computer in a different operator control room located at a remote location within the spray drying equipment. The operating mode can be understood as displaying the oHMI on the workstation's display, allowing the operator at the workstation to monitor, supervise, and control the actual spray drying equipment via the oHMI. The training mode can be understood as a mode that displays the tHMI on the workstation monitor, allowing operators to be trained.

[0030] In some implementations, when the workstation is in training mode, the control unit repeatedly assesses whether the spray drying equipment is in a steady state, and if the control unit determines that the steady-state conditions are not met, the control unit performs an operation to switch the workstation from training mode to operating mode.

[0031] When the tHMI and oHMI operate in a shared control room or on a shared workstation, the operator can combine supervision of the actual spray drying equipment with training on a simulated spray drying equipment. Since the spray drying equipment can operate essentially without operator supervision, this allows the operator at the workstation to receive tHMI training in training mode. Therefore, the operator being trained can optimize the time spent supervising the equipment, as they can focus on training on, for example, fault scenarios and maintenance procedures, rather than waiting for alarms from the SCADA system. The control unit determines whether the spray drying equipment is in a steady-state condition based on steady-state conditions that must be met. Steady-state conditions can be defined as thresholds for one or more parameters that should not be exceeded. These thresholds can be substantially similar to the thresholds defined in the SCADA system that trigger alarms to the oHMI and for operator supervision of the spray drying equipment. The control unit is operatively coupled to the PLC, the workstation, and can be operatively coupled to the processing unit.

[0032] In some implementations, the processing unit is configured to set the initial conditions of the instantaneous mode based on sensor data received from the spray drying equipment.

[0033] The processing unit can obtain the sensor data acquired by the spray drying equipment from the PLC. This allows for updating the instantaneous mode using real sensor data from the spray drying equipment, and thereby rendering the inputs and outputs of the instantaneous sub-mode. It also allows for updating the instantaneous mode, for example, when switching from operating mode to training mode, such that the values ​​displayed on the tHMI are substantially the same as those displayed on the oHMI. Therefore, the operator to be trained may not notice when the display has switched from oHMI to tHMI. One advantage of this is that the method according to the invention allows the training operator to switch from oHMI to tHMI on the workstation without the operator's notice. A fault scenario can then be loaded and started, for example, causing the operator to be trained to mistakenly believe that the fault scenario is real.

[0034] In some implementations, the method further includes the following steps:

[0035] • Provide pre-programmed fault scenarios for the processing unit;

[0036] • Based on pre-programmed fault scenarios, the transient mode is modified using the processing unit.

[0037] Pre-programmed fault scenarios can be understood as fault conditions that have been pre-programmed to train operators of spray drying equipment to understand known fault scenarios occurring on the spray drying equipment. Pre-programmed fault scenarios can be fault or error sensor data generated by the processing unit, where the fault sensor data indicates that one or more equipment components in the equipment are malfunctioning on the tHMI, thereby creating a fault training scenario. The tHMI can then be configured to receive user input for correcting the fault sensor data. Pre-programmed fault scenarios can include a set of parameters and / or preset values ​​or states that cause the spray drying equipment to malfunction or send a fault. For example, parameters and / or preset values ​​are parameters outside a threshold range, such as excessively low or high temperatures of the air inside the spray drying chamber. States, for example, include a pump disengagement command state or nozzle blockage in the spray drying chamber. When the processing unit sets a pre-programmed scenario, the transient mode is modified based on the content of the pre-programmed fault scenario. For example, this could be a set of parameters and / or preset values ​​as described above, which can change one or more inputs or outputs of the transient mode and one or more parameters of the transient mode. These changes and errors in sensor data can trigger errors and malfunctions, which then appear on the displayed tHMI, for example, as visual signals of one or more device components malfunctioning on the tHMI. These errors and malfunctions can then be handled by an operator to be trained. The operator can then process the malfunction scenario by performing user actions on the tHMI to correct the malfunction and get the modeled device running again. These actions performed by the operator on the tHMI, for example via a workstation, can then be recorded by the processing unit. For example, this could be a record of clicks performed by the operator on the workstation and the speed at which the malfunction scenario was resolved. Pre-programmed malfunction scenarios can be stored in a database, which the processing unit can access.

[0038] In some implementations, the method further includes the following steps:

[0039] • Provide the processing unit with best practice standards relevant to the first pre-programmed scenario;

[0040] • Evaluate operator performance using processing units based on best practice standards.

[0041] To evaluate an operator's performance during training on a tHMI when attempting to resolve a given fault scenario, the operator's actions must be compared to best practice standards for the fault scenario. Best practice standards may include time variables, such as resolving the fault within a given time interval to avoid irreversible damage to the spray drying equipment in a real-world fault situation. Operators may resolve fault scenarios in different ways, so there may be combinations that are better than others. This can also be weighted when evaluating performance. Evaluation can be automated, based on best practice standards, by comparing the operator's training results to a standard. The output of the evaluation can be a score, allowing comparison of results from different operators and tracking operator evolution by, for example, observing improvements in the score. The processing unit can also randomly select fault scenarios that the operator to be trained should face during training. There may be 5, 10, 15, 20, or 50 different fault scenarios to choose from. User input recording can be initiated immediately after the transient mode has been modified. In some implementations, the transient mode is configured to communicate with a transient mode human-machine interface (tmHMI), where the tmHMI is configured to control the transient mode by defining initial conditions for the transient mode and / or activating a specific pre-programmed fault scenario from a plurality of pre-programmed fault scenarios. The tmHMI can be displayed on a separate monitor, allowing a trainer to activate the pre-programmed fault scenario for the trainee. However, the tmHMI can also be displayed on the same monitor on which the tHMI is displayed, allowing an operator to be trained to select a pre-programmed fault scenario.

[0042] In some implementations, the method further includes the following steps:

[0043] • Displays the operator interface, allowing the operator to input auxiliary operator operations.

[0044] The operator interface allows operators to perform auxiliary operator actions. When operators are training on the tHMI at the workstation, they may not always be able to resolve fault scenarios by performing actions solely on the tHMI. Some real-world fault scenarios can be resolved simply by performing actions directly on the spray drying equipment, and it's impossible for an operator to resolve real-world fault scenarios solely by performing actions on the oHMI of the spray drying equipment, as only a limited number of actions can be performed from the oHMI. This can be accomplished in real-world scenarios by dispatching personnel to the equipment to resolve the fault scenario; these personnel are, for example, equipment technicians or engineers, electricians, plumbers, firefighters, etc., depending on the fault scenario. For training purposes, this can be simulated in the tHMI by generating or simulating an operator interface, allowing, for example, the performance of auxiliary operator actions, such as calling the equipment technician, electrician, plumber, firefighter, or supervisor of the spray drying equipment. The auxiliary operator actions that the operator can perform may be simulated as buttons that the operator can press with the mouse on the workstation, allowing the actions performed by the operator to be tracked, recorded, and evaluated. For example, the operator can click a button to simulate calling an equipment technician, and then confirm the auxiliary operator action by clicking another button. Therefore, the operator interface (OMI) can prepare operators for real-life scenarios where trained operators face situations requiring auxiliary operator intervention. This allows trained operators to be prepared and react more quickly in such situations. The OMI can be directly generated and displayed, for example, if a fault scenario can only be resolved through intervention by technicians. The OMI can be displayed on the same monitor as the tHMI. However, the OMI can also be displayed on a separate monitor.

[0045] In some implementations, the instantaneous mode is further updated based on operator input on the operator interface.

[0046] Therefore, the effects of performing auxiliary operator operations can be simulated. This allows operators to simulate replacing faulty equipment components and / or performing maintenance on faulty equipment components. This will allow for training beyond the scope of normal operation. This can be further used to evaluate the effectiveness of performing maintenance and / or replacement operations.

[0047] In some implementations, the transient sub-modes of multiple device elements include a first transient sub-mode that models a first device element in a first state, and the step of updating the transient mode based on operator input on an operator interface includes replacing the first transient sub-mode with a second transient sub-mode that models a first device element in a second state.

[0048] Therefore, auxiliary operations can be simulated. As an example, if the auxiliary operation includes calling a technician to perform maintenance on a device component, the first state can simulate the device component before the maintenance is performed, and the second state can simulate the device component after the maintenance is performed.

[0049] In some implementations, the operator interface is configured to allow the operator to instruct on device elements and auxiliary operations among multiple device components.

[0050] Therefore, more realistic training is provided. As an example, operators can be trained to identify specific faulty equipment components based on information provided in the tHMI.

[0051] In some implementations, the method further includes the following steps:

[0052] • Provide pre-programmed fault scenarios for the processing unit, simulating faults in multiple device components;

[0053] • Provide the processing unit with best practice standards related to pre-programmed fault scenarios;

[0054] • Modify the transient pattern based on a pre-programmed failure scenario by replacing the transient sub-pattern that models the equipment component that is about to fail with another transient sub-pattern that simulates the failure.

[0055] • Based on best practice standards, evaluate operator performance using processing units, where best practice standards include one or more specific auxiliary operator actions performed by the operator using the operator interface.

[0056] Therefore, operators can be trained and evaluated in complex situations.

[0057] In some implementations, specific one or more auxiliary operations simulate maintenance or replacement operations for faulty equipment components.

[0058] In this document and hereinafter, the term "processing unit" is intended to include any circuitry and / or apparatus suitable for performing the functions described herein. Specifically, the term includes general-purpose or proprietary programmable microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable logic arrays (PLAs), field-programmable gate arrays (FPGAs), special-purpose electronic circuits, and combinations thereof. Attached Figure Description

[0059] 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 invention with reference to the accompanying drawings, wherein:

[0060] Figure 1A block diagram is shown illustrating an example of a method for training an operator of a spray drying equipment according to an embodiment of the present invention.

[0061] Figure 2 A flowchart is shown for a method of training operators of spray drying equipment.

[0062] Figure 3 An example of an operator interface is shown, which allows the operator to input auxiliary operator operations.

[0063] Figure 4 A schematic diagram of a spray drying apparatus provided by an embodiment of the present invention is shown.

[0064] Figure 5 A schematic diagram of a computer system for training operators of spray drying equipment according to an embodiment of the present invention is shown. Detailed Implementation

[0065] Reference is made in the following description to the accompanying drawings, which illustrate by way of description how the invention can be practiced.

[0066] Figure 1 A block diagram illustrating an example of a method for training an operator of a spray drying equipment according to an embodiment of the present invention is shown. The spray drying equipment 170 includes a plurality of equipment elements, including a pretreatment element, a spray drying element, a post-treatment element, a powder recovery element, a programmable logic controller (PLC) 150, a plurality of sensors, and a plurality of active elements. The sensors are configured to measure process variables on the plurality of equipment elements and transmit sensor signals to the PLC 150. The active elements are configured to control the process variables of one or more of the plurality of equipment elements in response to control signals received from the PLC 150. The spray drying equipment 170 also includes an operator human-machine interface (oHMI) 130 configured to communicate with the PLC 150 and display multiple sensor data based on sensor data obtained from the plurality of sensors. The method further includes the following steps: obtaining a transient mode of the spray drying equipment 170, wherein the transient mode includes transient sub-modes of multiple equipment elements; repeatedly calculating analog sensor data using the processing unit 140 based on the obtained transient mode; displaying a training human-machine interface (tHMI) 120 on a display, the training HMI being configured to communicate with the transient mode of the spray drying equipment 170 and displaying analog sensor data and control data of the transient mode; and updating the transient mode based on operator input on the tHMI 120 for controlling the transient mode of the spray drying equipment 170.

[0067] PLC 150 is operatively connected to spray drying equipment 170, and thereby connected to one or more of a plurality of sensors and a plurality of active components. PLC 150 may be located at spray drying equipment 170 or alternatively located remotely from spray drying equipment 170 and in communication with the plurality of sensors and active components. PLC 150 is operatively connected to oHMI 130. Spray drying equipment 170 may receive control signals from the PLC, and the PLC may then control one or more components of spray drying equipment 170. Control signals may be pre-programmed in the PLC, or may be sent from the oHMI, received at the PLC, and then generated at the PLC.

[0068] The oHMI 130 can be included in a SCADA system installed on a workstation 160 in the control room of the spray drying equipment 170. The SCADA system can acquire sensor data and control data from the PLC.

[0069] The processing unit 140 repeatedly (i.e. continuously) calculates the analog sensor data 140 in order to update the tHMI 120 with the most recently calculated analog sensor data.

[0070] The tHMI 120 is operatively connected to the processing unit 140 and displays multiple analog sensor data and control data based on the obtained instantaneous patterns.

[0071] In an alternative implementation, tHMI 120 can be operatively connected to PLC 150. tHMI 120 and oHMI 130 can reside on different workstations 160 and thus be displayed on different monitors. oHMI 130 can be displayed, for example, on workstation 160 in the control room of the spray drying equipment 170. tHMI 120 can also be displayed on the monitor of workstation 160 in the control room of the spray drying equipment 170, but it can also be displayed on the monitors of different workstations in different training rooms. Processing unit 140 can be included in a common workstation 160 for oHMI 130 and tHMI 120 and updates the transient patterns stored at the common workstation 160. Alternatively, different processing units 140 can be included, for example, remotely on a server and can update the transient patterns on the server and communicate with workstation 160.

[0072] In an alternative implementation, control unit 110 is operatively coupled to PLC 150, workstation 160, and processing unit 140. When workstation 160 is in training mode, control unit 110 repeatedly evaluates whether spray drying equipment 170 is in a steady state. If control unit 110 determines that the steady-state condition is not met, control unit 110 performs an operation to switch workstation 160 from training mode to operating mode.

[0073] Figure 2 A flowchart is shown for a method of training an operator of a spray drying equipment via a control unit that switches between training and operating modes. When the workstation is in training mode, the control unit repeatedly assesses whether the spray drying equipment is in a steady state. If the control unit determines that the steady-state conditions are not met, it performs an operation to switch the workstation from training mode to operating mode. When the tHMI and oHMI are operating in a shared control room or on a shared workstation, the operator can thus combine supervision of the actual spray drying equipment with training on a simulated spray drying equipment.

[0074] Figure 3 An example of an operator interface 300 is shown, which allows the operator to perform auxiliary operator actions. When an operator performs training on the tHMI at a workstation, the operator may not always resolve fault scenarios by performing actions on the tHMI. Some real-world fault scenarios may only be resolved by directly operating the spray drying equipment. This can be accomplished by dispatching personnel to the equipment to resolve the fault scenario; these personnel may be, for example, equipment technicians or engineers, electricians, plumbers, firefighters, etc. For training purposes, this can be simulated in the tHMI by generating the operator interface 300, allowing, for example, the performance of auxiliary operator actions, such as calling the equipment technician, electrician, plumber, firefighter, or supervisor of the spray drying equipment. The actions that the operator can perform may be simulated as button 310 that the operator can press with the mouse on the workstation, so that the actions performed by the operator can be tracked and recorded. The operator can, for example, click the button to simulate calling the equipment technician, and then confirm by clicking the button to perform the auxiliary operator action.

[0075] Figure 4A schematic diagram of a spray drying apparatus 400 for milk spray drying is shown, including 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 fluidized bed 470, a cyclone dust collector 480, a bag filter 490, and a powder silo 495. In this paper, an example of a spray drying process is milk spray drying for the manufacture of milk powder. Liquid milk is stored in the milk buffer tank 410. The milk is then pretreated using the first and second centrifugal pumps 420 and 440, the evaporator 430, and the homogenizer 450 to substantially remove the water content from the liquid milk. The concentrated milk is then pumped into the spray drying chamber 460 for spray drying, where it is atomized through atomizers such as high-pressure nozzles while a continuous stream of warm, dry air is pumped into the chamber. This removes most of the water content from the milk droplets. Since it is impossible to prevent the dry air from capturing a small portion of the dry matter content in most cases, the air undergoes a post-treatment process through a cyclone dust collector 480 and a bag filter 490. The collected dry matter is then returned to the process. However, most of the dry matter content in the milk falls to the bottom of the spray drying chamber 460 as milk powder. The powder does not remain at the bottom of the spray drying chamber because the bottom is a fluidized bed 470. The powdered milk is then stored in a powder silo 495 until the silo is emptied.

[0076] Figure 5A schematic diagram of a computer system 500 for training an operator of a spray drying equipment according to an embodiment of the present invention is shown. The computer system includes multiple functional blocks, specifically a transient mode functional block 501 simulating a real spray drying equipment, a simulated PLC 502 simulating a PLC of a real spray drying equipment, a database functional block 505 storing multiple pre-programmed fault scenarios, a training human-machine interface (tHMI) functional block 503, and a transient mode interface (tmHMI) functional block 504. The training HMI functional block is configured to allow the operator to interact with the transient mode functional block 501 and refer to simulated sensor data. The tmHMI functional block is configured to allow the trainee to interact with the transient mode 501 to set initial conditions for the transient mode functional block 501 and / or activate pre-programmed fault scenarios stored in the database functional block 505. By using the simulated PLC functional block 502, the program code of the oHMI used at the real equipment can be directly used in the tHMI, thereby making the training more realistic. Furthermore, this makes it easier to modify the tHMI; if the oHMI changes, only the new program code for the modified oHMI needs to be reused. Different function blocks can be implemented in different ways; for example, the analog PLC function block 502, the instantaneous mode function block 501, and the database function block 505 can be implemented on server 506, the tHMI function block 503 can be implemented on the first workstation 507, and the tmHMI function block 504 can be implemented on the second workstation 508. However, the analog PLC function block 502, the instantaneous mode function block 501, and the database function block 505 can also be implemented on two or more servers, or all function blocks can even be implemented in a single workstation.

[0077] Although some embodiments have been described and illustrated in detail, the invention is not limited to these embodiments, and may be embodied in other ways within the scope of the subject matter defined in the following claims. In particular, it should be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the invention.

[0078] In apparatus claims that enumerate several methods, some of these methods can be implemented by the same hardware item. The fact that certain means are referenced in different dependent claims or described in different embodiments does not mean that combinations of these methods cannot be used to achieve advantages.

[0079] It should be emphasized that, when used in this specification, the term "comprising" is used to specify the presence of the said feature, integer, step, or component, but does not exclude the presence or addition of one or more other features, integers, steps, components, or combinations thereof.

Claims

1. A method for training an operator of a spray drying plant, the spray drying plant comprising a plurality of plant elements, the plurality of plant elements comprising a pre-treatment element, a spray drying element, a post-treatment element, a powder recovery element, 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 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 operator human machine interface, oHMI, configured to communicate with the PLC and display a plurality of sensor data based on sensor signals obtained from the plurality of sensors; the method comprising the steps of: obtaining a transient mode of the spray drying plant, wherein the transient mode comprises transient sub-modes of the plurality of plant elements; repeatedly calculating simulated sensor data using a processing unit based on the obtained transient mode; displaying a training human machine interface, tHMI, on a display, the training human machine interface configured to communicate with the transient mode of the spray drying plant and display the simulated sensor data and control data of the transient mode; and updating the transient mode based on operator input on the tHMI for controlling the transient mode of the spray drying plant; wherein the spray drying plant further comprises an operator control room, the operator control room having a workstation equipped with a display, the workstation having an operation mode and a training mode, wherein the workstation is configured to display the oHMI in the operation mode and the tHMI in the training mode on the display, wherein when the workstation is in the training mode, a control unit repeatedly assesses whether the spray drying plant is in a steady state, and if the control unit determines that the steady state condition is not met, the control unit performs an operation to switch the workstation from the training mode to the operation mode, wherein the processing unit is configured to set initial conditions of the transient mode based on sensor data received from the spray drying plant such that values displayed on the tHMI are substantially the same as values displayed on the oHMI, and wherein an operator switches from the oHMI to the tHMI on the workstation for training and subsequently loading and starting a fault scenario without the attention of an operator.

2. The method according to claim 1, wherein the transient sub-modes of a spray drying chamber are based on one or more inputs and one or more outputs, wherein the one or more inputs and the one or more outputs comprise one or more of: mass flow, temperature and vapor fraction of air entering the spray drying chamber, or mass flow, temperature and solid fraction in a product to be dried. ​ 3. The method of claim 1 or 2, wherein the transient sub-mode of the spray drying chamber comprises a modeling of at least one of: a volume of the spray drying chamber, a heat loss through a surface area of the spray drying chamber, a thickness of a wall of the spray drying chamber, a heat capacity of a wall of the spray drying chamber, a heat transfer coefficient of air to wall, a heat transfer coefficient of a product to be spray dried, an evaporation efficiency of the product to be spray dried, and a fine particle fraction of the product to be spray dried.

4. The method of claim 1 or 2, wherein at least a portion of the tHMI visual layout is the same as the oHMI.

5. The method of claim 1 or 2, further comprising the steps of: providing the processing unit with pre-programmed failure scenarios; modifying the transient mode using the processing unit based on the pre-programmed failure scenarios.

6. The method of claim 5, further comprising the steps of: providing the processing unit with best practice standards related to a first pre-programmed scenario; evaluating the operator’s performance using the processing unit based on the best practice standards.

7. The method of claim 1, wherein the transient mode is configured to communicate with a transient mode human machine interface (tmHMI), wherein the tmHMI is configured to control the transient mode by setting initial conditions of the transient mode and / or activating a particular pre-programmed failure scenario of a plurality of pre-programmed failure scenarios.

8. The method of claim 1 or 2, further comprising the steps of: displaying an operator interface allowing an operator to input an auxiliary operator action.

9. The method of claim 8, wherein the transient mode is further updated based on operator input on the operator interface.

10. The method of claim 9, wherein the transient sub-mode of the plurality of equipment elements comprises a first transient sub-mode modeling a first equipment element in a first state, and wherein the step of updating the transient mode based on operator input on the operator interface comprises replacing the first transient sub-mode with a second transient sub-mode modeling the first equipment element in a second state.

11. The method of claim 10, wherein the operator interface is configured to allow an operator to indicate an equipment element of the plurality of equipment elements and an auxiliary action.

12. The method of claim 8, wherein the method further comprises the steps of: providing the processing unit with a pre-programmed failure scenario simulating a failure of an equipment element of the plurality of equipment elements; providing the processing unit with best practice standards related to the pre-programmed failure scenario; modifying the transient mode based on the pre-programmed failure scenario by replacing a transient sub-mode modeling the equipment element to fail with another transient sub-mode simulating the failure; evaluating the operator’s performance using the processing unit based on the best practice standards, wherein the best practice standard includes a particular one or more secondary operator operations to be performed by the operator using the operator interface.

13. The method of claim 12, wherein the particular one or more secondary operator operations simulate a maintenance operation or a replacement operation on the faulty device element.

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