CN211577728U - Advanced control system for liquefied natural gas preparation and LNG production system - Google Patents
Advanced control system for liquefied natural gas preparation and LNG production system Download PDFInfo
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- CN211577728U CN211577728U CN202020140257.8U CN202020140257U CN211577728U CN 211577728 U CN211577728 U CN 211577728U CN 202020140257 U CN202020140257 U CN 202020140257U CN 211577728 U CN211577728 U CN 211577728U
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Abstract
The application relates to the technical field of clean energy preparation by deep processing of coke oven gas, in particular to an advanced control system for liquefied natural gas preparation and an LNG production system, wherein the advanced control system for liquefied natural gas preparation comprises: the distributed control device comprises a detection assembly and a distributed controller assembly which are in communication connection; the advanced control device comprises a real-time database, a model storage module, a prediction module and a control module which are mutually communicated and connected. The advanced control system of liquefied natural gas preparation that this application provided can in time make the regulation and control instruction according to predetermined operation standard through carrying out automatic accurate regulation and control, makes individual part operation data maintain throughout in optimizing the interval in liquefied natural gas's the preparation process, ensures that technological parameter floats in allowing the correction error range, has reduced the energy consumption in the natural gas preparation process, highly realizes the automation.
Description
Technical Field
The application relates to the technical field of clean energy preparation by deep processing of coke oven gas, in particular to an advanced control system for preparing liquefied natural gas and an LNG (liquefied natural gas) production system.
Background
The device for preparing LNG from coke oven gas takes coke oven gas which is a byproduct in the coking industry as a raw material, impurities such as tar and naphthalene are removed through compression and activated carbon adsorption, then redundant oxygen is removed in a deoxygenation reactor to prevent ignition and explosion in the subsequent compression process, and then part of CO is removed through pressure swing adsorption2The hydrogen-carbon ratio is adjusted to a proper level, and then hydrodesulfurization is carried out by raising the temperature, so that organic sulfur in the system is converted into inorganic sulfur and the inorganic sulfur is removed to be below 20 ppb. Then the mixture enters two-stage methanation synthesis, namely CO and CO in the coke oven gas2And H2Complete reaction to form CH4In the synthesis reaction, a waste heat boiler removes the synthesis reaction heat to generate 3.8MPa saturated steam as the power of a compressor. After the synthesis reaction, SNG (Synthetic Natural Gas, Natural Gas produced by raw coal through a gasification process) enters a molecular sieve to remove water, so that the freezing blockage in a subsequent cold box is prevented, and the dew point of a dehydration position is reduced to below-75 ℃. The dehydrated SNG enters a cold box, is Liquefied under the action of cold energy provided by a mixed refrigerant compressor, and then is subjected to cryogenic rectification processes of a low-pressure tower and a high-pressure tower respectively to remove nitrogen and hydrogen, and the residual methane is completely Liquefied into LNG (Liquefied Natural Gas), and is sent to an LNG storage tank for storage.
The coke oven gas-to-LNG apparatus is generally equipped with a Distributed Control System (DCS), that is, a Distributed Control apparatus in this embodiment, which is to implement real-time monitoring of the entire process of the apparatus by connecting detection instruments such as temperature, pressure, flow, liquid level, and components to the DCS, then the DCS calculates Control actions according to Control targets set by an operator according to Control schemes such as conventional PID (proportional, integral, differential), cascade, and the like in the DCS, and finally the DCS sends Control results to an adjusting valve, a shut-off valve, a frequency converter, and the like for execution, and the steps are repeated in a cycle.
However, because the gas quantity and the gas quality components of the upstream gas source of the device for preparing the LNG from the coke oven gas are variable, the process is complex, and the device has the characteristics of multivariable, nonlinearity, strong coupling, large hysteresis and the like, the conventional single-input single-output PID control scheme of the DCS system cannot meet the control requirements easily. When facing a complex control object, an operator is difficult to accurately predict a future trend and comprehensively coordinate all bottom-layer PID loops, so that the following problems are caused: 1. the fluctuation of important process parameters such as the temperature of the deoxygenation reactor, the temperature of the synthesis reactor, the temperature of the cold box and the like is large, and the device is not stable in operation; 2. the more important loop is the more often the loop is in a manual mode by an operator, the automation level is very low, the manual operation is more, and the working intensity of the operator is very high; 3. the device can not operate in an optimized interval, so that the system has high energy consumption, low yield and the like.
SUMMERY OF THE UTILITY MODEL
The application aims to provide an advanced control system for liquefied natural gas preparation and an LNG production system, so as to solve the technical problems of low automatic control application rate and large technological parameter fluctuation in the prior art to a certain extent.
The application provides an advanced control system for liquefied natural gas preparation, which is used for a liquefied natural gas preparation device, wherein the liquefied natural gas preparation device comprises a purification system, a synthesis system, a liquefaction system and an adjusting component, the purification system, the synthesis system and the liquefaction system are sequentially connected, and the adjusting component is arranged on the purification system, the synthesis system and the liquefaction system;
the advanced control system for preparing the liquefied natural gas comprises a distributed control device and an advanced control device, wherein the distributed control device comprises a detection assembly and a distributed controller assembly which are in communication connection; the advanced control device comprises a real-time database, a model storage module, a prediction module and a control module which are in communication connection with each other; the model storage module stores purification model data, synthesis model data and liquefaction model data;
the real-time database and the control module are in communication connection with the distributed controller assembly; the detection component respectively acquires instant data of controllable variables of the purification system, the synthesis system and the liquefaction system, and transmits and stores the instant data to the real-time database; the real-time database stores historical data;
the prediction module can predict the change trend of the controllable variable in a preset time according to the purification model data, the synthesis model data, the liquefaction model data and the historical data;
the control module can calculate the optimal operation amount for the adjusting assembly according to the change trend and a preset ideal value and transmit the optimal operation amount to the distributed controller assembly;
and the distributed controller component adjusts the adjusting component according to the optimal operation amount so that the controllable variable works at the preset ideal value.
In the above technical solution, further, the advanced control apparatus further includes a feedback correction module; the feedback correction module is respectively in communication connection with the real-time database, the model storage module, the prediction module and the control module;
and the feedback correction module corrects the purification model data, the synthesis model data and the liquefaction model data according to the instant data and the change trend.
In any of the above technical solutions, further, the detecting component includes a first detecting component, a second detecting component and a third detecting component;
the first detection assembly can acquire first instant data of a first controllable variable of the purification system, and transmits and stores the first instant data in the real-time database;
the second detection component can acquire second instant data of a second controllable variable of the synthesis system, and transmit and store the second instant data in the real-time database;
the third detection assembly can acquire third instant data of a third controllable variable of the liquefaction system, and the third instant data is transmitted and stored in the real-time database.
In any of the above technical solutions, further, the control module includes a purification controller, a synthesis controller, and a liquefaction controller;
the regulating assembly comprises a first regulating assembly arranged in the purification system, a second regulating assembly arranged in the synthesis system and a third regulating assembly arranged in the liquefaction system;
the prediction module can predict a first change trend of the first controllable variable in the preset time according to the first instant data, the purification model data and the historical data; the purge controller is capable of calculating a first optimum operation amount for the first adjusting component based on the first tendency of change and the predetermined ideal value;
the prediction module is further capable of predicting a second change trend of the second controllable variable within the preset time according to the second instant data, the synthetic model data and the historical data; the synthesizing controller is capable of calculating a second optimum operation amount for the second adjusting component based on the second tendency of change and the predetermined ideal value;
the prediction module is further capable of predicting a third change trend of the third controllable variable within the preset time according to the third instant data, the liquefaction model data and the historical data; the liquefaction controller may be configured to calculate a third optimum operation amount for the third regulation component based on the third tendency of change and the predetermined ideal value.
In any of the above solutions, further, the first adjusting component includes at least a first valve at an inlet of the purification system, and a second valve at an outlet of the purification system;
the first detection assembly at least comprises a first temperature detector and an oxygen content detector of the outlet of the purification system;
the purge model data is control model data of a set quantity of the first adjusting component to a detected quantity of the first detecting component.
In any of the above solutions, further, the second adjusting component at least includes a third valve disposed at an inlet of the synthesis system, and a fourth valve of the synthesis system;
the second detection assembly comprises at least a second temperature detector at the inlet of the synthesis system, a third temperature detector at the outlet of the synthesis system;
the synthetic model data is control model data of the set quantity of the second adjusting component to the detected quantity of the second detecting component.
In any of the above solutions, further, the third adjusting component includes a fifth valve disposed at an inlet of the liquefaction system, and a sixth valve disposed at an outlet of the liquefaction system;
the third detection assembly comprises a fourth temperature detector, a density detector and a pressure detector which are arranged in the liquefaction system;
the liquefaction model data is control model data of the set quantity of the third regulating module to the detected quantity of the third detecting module.
In any of the above technical solutions, further, the distributed controller assembly further includes a distributed controller, a control device, and a display device; the control equipment and the display equipment are connected with the distributed controller.
In any of the above technical solutions, further, the system further includes a first communication device, a second communication device, and an OPC server; the distributed controller assembly communicates with the OPC server via the first communication device and the control module communicates with the OPC server via the second communication device.
The application also provides an LNG production system, which comprises the advanced control system for preparing the liquefied natural gas according to any technical scheme, so that all the beneficial technical effects of the advanced control system for preparing the liquefied natural gas are achieved, and the detailed description is omitted.
Compared with the prior art, the beneficial effect of this application is:
the advanced control system for preparing the liquefied natural gas comprises a distributed control device and an advanced control device, wherein the distributed control device comprises a detection assembly and a distributed controller assembly which are in communication connection; the advanced control device comprises a real-time database, a model storage module, a prediction module and a control module which are mutually communicated and connected; the model storage module stores purification model data, synthesis model data and liquefaction model data; the method provides an accurate simulation environment for predicting the change trend of the prediction module by establishing the purification model data, the synthesis model data and the liquefaction model data, so that the obtained change trend is more fit with the actual change rule, the accuracy of prejudgment is improved, the change trend is compared with a preset ideal value to obtain the optimal operation amount, compared with a scheme of directly obtaining a control instruction through a distributed controller assembly, the method can better adapt to the multivariable, nonlinear, strong coupling and large lag operation characteristics of the liquefied natural gas preparation device, the working state of the liquefied natural gas preparation device is close to the ideal state to the maximum extent through a series of automatic control processes, the working amount of operators is effectively reduced, importantly, the automation level is improved, the regulation precision is remarkably improved, the process parameter poking is reduced, and the safety of the liquefied natural gas preparation device in the operation process is enhanced, The stability and the energy consumption can be reduced.
The application provides a LNG production system, includes the aforesaid the advanced control system of liquefied natural gas preparation, therefore, make the preparation process of liquefied weather highly realize the automation through this advanced control system of liquefied natural gas preparation, reduced staff's working strength, also avoided manual adjustment to produce great error, reduced the energy consumption of liquefied natural gas preparation in-process, highly realize the automation.
Drawings
In order to more clearly illustrate the detailed description of the present application or the technical solutions in the prior art, the drawings needed to be used in the detailed description of the present application or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic process flow diagram of an advanced control system for LNG production provided by an embodiment of the present application;
FIG. 2 is a schematic structural diagram of an advanced control system for preparing liquefied natural gas according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of a control module of an advanced lng preparation control system according to an embodiment of the present disclosure.
Reference numerals:
101-deoiling and decalcification device, 102-deoxidizing device, 103-synthetic gas compression device, 104-decarbonization device, 105-hydrodesulfurization device, 106-main reaction device, 107-auxiliary reaction device, 108-dehydration molecular sieve, 201-real-time database, 202-prediction module, 203-feedback correction module, 204-control module, 2041-synthesis controller, 2042-purification controller, 2043-liquefaction controller, 205-model storage module, 206-system configuration, 3-distributed control device, 4-OPC server, 5-gas cabinet, 6-storage tank, 7-liquefaction system and 8-raw gas compression device.
Detailed Description
The technical solutions of the present application will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are only some embodiments of the present application, but not all embodiments.
The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application.
All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
The advanced control system for LNG production and the LNG production system according to some embodiments of the present application will be described with reference to fig. 1 to 3.
Example one
Referring to fig. 1 to 3, an embodiment of the present application provides an advanced control system for lng production, which is used for an lng production apparatus, where the lng production apparatus includes a purification system, a synthesis system, a liquefaction system, and a regulation component, the purification system, the synthesis system, and the liquefaction system are connected in sequence, and the regulation component is disposed in the purification system, the synthesis system, and the liquefaction system; the advanced control system for preparing the liquefied natural gas comprises a distributed control device 3 and an advanced control device, wherein the distributed control device 3 comprises a detection assembly and a distributed controller assembly which are in communication connection; the advanced control device comprises a real-time database 201, a model storage module 205, a prediction module 202 and a control module 204 which are mutually communicated; the model storage module 205 stores the cleaning model data, the synthetic model data, and the liquefaction model data; the real-time database 201 and the control module 204 are in communication connection with the distributed controller component; the detection component respectively acquires the instant data of the controllable variables of the purification system, the synthesis system and the liquefaction system, and transmits and stores the instant data to the real-time database; the real-time database 201 stores historical data; the prediction module 202 can predict the variation trend of the controllable variable within the preset time according to the purification model data, the synthesis model data, the liquefaction model data and the historical data; the control module 204 can calculate the optimal operation amount for the adjusting assembly according to the variation trend and the preset ideal value, and transmit the optimal operation amount to the distributed controller assembly; the distributed controller component adjusts the adjusting component according to the optimal operation quantity so that the controllable variable works at a preset ideal value.
Specifically, referring to fig. 1 to 3, the lng production apparatus includes a purification system, a synthesis system, and a liquefaction system, which are sequentially communicated; the purification system is used for purifying the raw materials, and the raw materials treated by the purification system enter the synthesis system to form natural gas; the liquefaction system is used to liquefy gaseous natural gas.
The purification system comprises a deoiling and decalcification device 101, a deoxidation device 102, a synthesis gas compression device 103, a decarburization device 104 and a hydrodesulfurization device 105 which are connected in sequence, and the specific purification process flow is a mature process in the prior art, and a person skilled in the art can fully understand the process and does not need to describe more.
The synthesis system comprises a main reaction device 106, a side reaction device 107 and a dehydration molecular sieve 108 which are connected in sequence, and the purified gas raw material can be synthesized into natural gas through two-step reaction, the synthesis process of the natural gas is a mature process in the prior art and is not described herein again, and then the natural gas is liquefied into a liquid state through a liquefaction system.
Preferably, the liquefied natural gas production apparatus further includes: a gas holder 5, a storage tank 6 and a liquefaction system 7; the gas holder 5 is communicated with the purification system, and coke oven gas is stored in the gas holder 5 and used for providing the coke oven gas into the purification system; the synthesis system, the liquefaction system 7 and the storage tank 6 are communicated in sequence.
The coke oven gas stored in the gas holder 5 is used as a raw material to enter a purification system (cryogenic rectification device) for purification treatment, the purified raw material enters a synthesis system to synthesize natural gas, and the cryogenic rectification device is arranged between the synthesis system and the storage tank 6 to ensure that the gaseous natural gas is gasified into liquefied natural gas and flows into the storage tank 6 for storage.
Wherein, a raw material gas compression device 8 is also arranged between the gas holder 5 and the purification system and is used for compressing the coke oven gas and then discharging the compressed coke oven gas into the purification system.
It should be noted that the distributed control apparatus 3 is a common apparatus in the existing natural gas preparation process, and can meet the requirements of the embodiment of the present application, and no specific requirements are made on the model and the brand of the distributed control apparatus 3.
In addition, the control module 204 performs an optimization control by rolling in each predetermined duty cycle (30 seconds for each predetermined duty cycle in this application) to minimize the error between the controlled variable and a desired trajectory in a future time interval. The optimized rolling implementation can timely find uncertainty caused by model mismatch, time variation, interference and the like and timely make up for the uncertainty, so that the control is kept to be actually optimal.
Preferably, the control module 204 further includes a system configuration 206, and the system configuration 206 includes, but is not limited to, important information of the advanced control device, including various file paths, server addresses, configurations of input and output points, operation information of the control module 204, various control and optimization parameter configurations, and the like required for the operation of the control module 204.
The advanced control system for preparing the liquefied natural gas comprises a distributed control device 3 and an advanced control device, wherein the distributed control device 3 comprises a detection assembly and a distributed controller assembly which are in communication connection; the advanced control device comprises a real-time database 201, a model storage module 205, a prediction module 202 and a control module 204 which are mutually communicated; the model storage module 205 stores the cleaning model data, the synthetic model data, and the liquefaction model data; the method provides an accurate simulation environment for the prediction module 202 to predict the change trend by establishing the purification model data, the synthesis model data and the liquefaction model data, so that the obtained change trend is more fit with the actual change rule, the accuracy of prediction is improved, the change trend is compared with a preset ideal value to obtain the optimal operation amount, compared with a scheme of directly obtaining a control instruction through a distributed controller assembly, the method can better adapt to the multivariable, nonlinear, strong coupling and large lag operation characteristics of the liquefied natural gas preparation device, the working state of the liquefied natural gas preparation device is close to the ideal state to the maximum extent through a series of automatic control processes, the working amount of operators is effectively reduced, importantly, the automation level is improved, the regulation precision is obviously improved, the process parameter poking is reduced, and the safety of the liquefied natural gas preparation device in the operation process is enhanced, The stability and the energy consumption can be reduced.
It should be noted that, in the embodiment of the present application, logic (program) interacting with the advanced control device is developed inside the distributed control device 3 by the advanced control device, and mainly includes watchdog logic (communication handshake logic), controller switching logic, loop switching logic, out-of-limit or stuck-limit alarm, and the like.
Preferably, the advanced control apparatus further comprises a feedback correction module 203; the feedback correction module 203 is respectively in communication connection with the real-time database 201, the model storage module 205, the prediction module 202 and the control module 204;
the feedback correction module 203 corrects the purge model data, the synthetic model data, and the liquefaction model data based on the instantaneous data and the trend of change.
In this embodiment, by continuously correcting the chemical model data, the synthetic model data, and the liquefied model data, it is possible to prevent the operation amount calculated by the advanced control device from excessively deviating from the ideal state due to environmental disturbance caused by mismatch of the model data.
In addition, the real-time database 201 can be used to store the instant data of the gold control device and all the related information of the prediction module 202, the feedback correction module 203 and the control module 204 during the operation of the advanced control device, so as to facilitate the system debugging or problem analysis. All relevant information includes, but is not limited to, process data, operational records, modification records, fault and error diagnostic records, and the like.
Preferably, the detection assembly comprises a first detection assembly, a second detection assembly and a third detection assembly;
the first detection component can acquire first instant data of a first controllable variable of the purification system, and transmits and stores the first instant data in the real-time database 201;
the second detection component can acquire second instant data of a second controllable variable of the synthesis system, and transmit and store the second instant data in the real-time database 201;
the third detection component can acquire third instant data of a third controllable variable of the liquefaction system, and transmit and store the third instant data in the real-time database 201.
In this embodiment, the purification system, the synthesis system, and the liquefaction system are respectively detected by three sets of detection components, and the operation state of the lng preparation apparatus is carefully monitored.
Preferably, the control module 204 includes a purge controller 2042, a synthesis controller 2041, and a liquefaction controller 2043;
the regulating assembly comprises a first regulating assembly arranged in the purification system, a second regulating assembly arranged in the synthesis system and a third regulating assembly arranged in the liquefaction system;
the prediction module 202 can predict a first change trend of the first controllable variable within a preset time according to the first instant data, the purification model data and the historical data; the purge controller 2042 is capable of calculating a first optimum operation amount for the first regulation component based on the first tendency of change and a predetermined desired value;
the prediction module 202 can also predict a second variation trend of the second controllable variable within the preset time according to the second instant data, the synthetic model data and the historical data; the synthesis controller 2041 is capable of calculating a second optimum operation amount for the second regulation component from the second tendency of change and the predetermined ideal value;
the prediction module 202 can also predict a third variation trend of the third controllable variable within the preset time according to the third instant data, the liquefaction model data and the historical data; the liquefaction controller 2043 is able to calculate a third optimum operation amount for the third regulation assembly based on the third tendency of change and the predetermined ideal value.
In this embodiment, the purification controller 2042, the synthesis controller 2041, the liquefaction controller 2043, the three detection assemblies, and the three adjustment assemblies cooperate with one another to significantly improve the optimal control capability of the control module 204, so as to optimize parameters of each part of the purification system, the synthesis system, the liquefaction system, and the like.
The first regulating component comprises a first valve at the inlet of the purification system and a second valve at the outlet of the purification system;
the first detection assembly comprises a first temperature detector and an oxygen content detector at the outlet of the purification system;
the purge model data is control model data of the set quantity of the first adjusting component to the detected quantity of the first detecting component.
Further, the second regulating assembly comprises a third valve arranged at the inlet of the synthesis system, and a fourth valve of the synthesis system;
the second detection assembly comprises a second temperature detector at the inlet of the synthesis system and a third temperature detector at the outlet of the synthesis system;
the synthetic model data is control model data of the set quantity of the second adjusting component to the detected quantity of the second detecting component.
Further, the third regulating component comprises a fifth valve arranged at the inlet of the liquefaction system and a sixth valve arranged at the outlet of the liquefaction system;
the third detection assembly comprises a fourth temperature detector, a density detector and a pressure detector which are arranged in the liquefaction system;
the liquefaction model data is control model data of the set quantity of the third regulating module to the detected quantity of the third detecting module.
It should be noted that the adjusting assembly includes valves and switches disposed on connecting pipelines of the lng preparation apparatus, and can be selected and controlled according to actual adjustment requirements of the lng preparation apparatus in an actual adjustment process or according to all sub-model data stored in the model storage module 205.
Similarly, the detection component comprises each detection instrument or sensor arranged on each connecting pipeline of the liquefied natural gas preparation device, and the detection instruments or sensors are selected and arranged according to actual conditions, so that the detection instruments or sensors can be completely understood by the technical personnel in the field and are not described in detail herein.
Wherein cleansing the model data comprises:
(1) the inlet temperature setting value of the fine desulfurization tower is a control model of the outlet temperature of the fine desulfurization tower;
(2) a control model of the circulation ratio set value of the circulation gas compressor to the inlet temperature of the main methanation reactor;
(3) a control model of the circulation ratio set value of the circulation gas compressor to the outlet temperature of the main methanation reactor;
(4) a control model of the circulation ratio set value of the circulation gas compressor to the inlet temperature of the auxiliary methanation reactor;
(5) a control model of the circulation ratio set value of the circulation gas compressor to the outlet temperature of the auxiliary methanation reactor;
(6) a control model of the opening degree of a bypass valve of the decarburization device to the inlet temperature of the main methanation reactor;
(7) a control model of the opening degree of a bypass valve of the decarburization device to the outlet temperature of the main methanation reactor;
(8) a control model of the opening degree of a bypass valve of the decarburization device to the inlet temperature of the auxiliary methanation reactor;
(9) a control model of the opening degree of a bypass valve of the decarburization device to the outlet temperature of the auxiliary methanation reactor;
(10) synthesizing an interference model of inlet flow to the inlet temperature of the main methanation reactor;
(11) synthesizing an interference model of inlet flow to the outlet temperature of the main methanation reactor;
(12) synthesizing an interference model of inlet flow to the inlet temperature of the auxiliary methanation reactor;
(13) and synthesizing an interference model of the inlet flow to the outlet temperature of the secondary methanation reactor.
Wherein the synthetic model data includes
(1) A control model of the refrigerant compressor rotation speed set value to the SNG entering low-pressure tower temperature;
(2) a control model of the LNG density by the set value of the rotating speed of the refrigerant compressor;
(3) a, a control model of the inlet pressure set value of a nitrogen compressor to the tower top temperature of a high-pressure tower;
(4) a, a control model of the inlet pressure set value of a nitrogen compressor to the tower top temperature of a low-pressure tower;
(5) b, a control model of the inlet pressure set value of the nitrogen compressor to the tower top temperature of the high-pressure tower;
(6) b, a control model of the inlet pressure set value of the nitrogen compressor to the tower top temperature of the low-pressure tower;
(7) and the flow measurement value of the SNG entering the cold box is a control model of the temperature of the SNG entering the low-pressure tower.
Wherein the liquefaction model data comprises:
(1) a control model of the refrigerant compressor rotation speed set value to the SNG entering low-pressure tower temperature;
(2) a control model of the LNG density by the set value of the rotating speed of the refrigerant compressor;
(3) a, a control model of the inlet pressure set value of a nitrogen compressor to the tower top temperature of a high-pressure tower;
(4) a, a control model of the inlet pressure set value of a nitrogen compressor to the tower top temperature of a low-pressure tower;
(5) b, a control model of the inlet pressure set value of the nitrogen compressor to the tower top temperature of the high-pressure tower;
(6) b, a control model of the inlet pressure set value of the nitrogen compressor to the tower top temperature of the low-pressure tower;
(7) and the flow measurement value of the SNG entering the cold box is a control model of the temperature of the SNG entering the low-pressure tower.
The multiple submodels are divided in detail under the main submodels, so that the advanced control device provided by the application can comprehensively and finely realize automation of the operation process of the liquefied natural gas preparation device.
Preferably, the distributed controller assembly further comprises a distributed controller, a control device and a display device; the control equipment and the display equipment are connected with the distributed controller.
In this embodiment, an operator can set the threshold values and the predetermined ideal values of the controllable variables and the adjusting components, and the high-low limit settings in a dedicated operating device, and the phase control module 204 sends switching instructions, and at the same time, the operator can perform data monitoring through a display device.
Preferably, a first communication device, a second communication device and an OPC server 4 are also included; the distributed controller component communicates with the OPC server 4 via a first communication device and the control module 204 communicates with the OPC server 4 via a second communication device (i.e., the purge controller 2042, the synthesis controller 2041, and the liquefaction controller 2043 all communicate with the OPC server 4).
In this embodiment, the advanced controller component is communicatively connected to the distributed controller component through the OPC server 4, and it should be noted that the advanced controller component runs on an independent dedicated APC (advanced process control system), so that the advanced controller component provided by the present application has a simple structure, and does not require a worker to spend much time and effort on connection and integration of each module, and the server may be a rack or a tower, and is communicatively connected to the OPC server 4 through an ethernet network.
In addition, the OPC server 4 may be set separately, or may be multiplexed after the DCS engineer station or the operator station activates the OPC service authorization, and separate setting is recommended if the conditions permit. The OPC server 4 is configured with a double network card or a triple network card, one network card is connected with the advanced control device, and the other or two network cards are connected with the DCS system.
Example two
Referring to fig. 1, an embodiment of the present application further provides an LNG production system, which includes all the technical features of the first embodiment, and further has all the beneficial effects of the first embodiment, and the same technical features are not described again.
The LNG production system provided in this embodiment includes a LNG production facility and an advanced LNG production control system as in the first embodiment.
Compared with the prior art, the method has the following advantages:
the advanced control system for preparing the liquefied natural gas comprehensively applies the OPC communication technology, the model prediction control technology, the soft measurement technology and the like, and designs a control scheme based on a process mechanism of preparing the LNG from the coke oven gas. The following effects can be achieved: 1. the automatic control of the liquefied natural gas preparation device is realized, such as multivariable coordination control of the temperature of the deoxygenation reactor, the temperature of the hydrogenation reactor, the temperature of the synthesis reactor, the temperature of the SNG entering the rectifying tower and the like, the automatic adaptation of the coke oven gas flow and the coke oven gas quality components is realized, the automation level of the device is greatly improved, and the labor intensity of operators is reduced; 2. the fluctuation range of key process parameters is reduced by 64.23 percent, and the stability and the safety of the device are improved; 3. the heat recovery is increased, the temperature difference of the heating furnace is reduced, and the fuel consumption is reduced; the rotating speed of the refrigerant compressor is optimized, the steam consumption is reduced, and further the fuel consumption is reduced; 4. the liquefied natural gas preparation device can improve the quality and reduce the consumption by about 1.2 percent through the application of an advanced control device, and the economic benefit is millions yuan each year.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (10)
1. An advanced control system for liquefied natural gas preparation is used for a liquefied natural gas preparation device, and is characterized in that the liquefied natural gas preparation device comprises a purification system, a synthesis system, a liquefaction system and an adjusting assembly, wherein the purification system, the synthesis system and the liquefaction system are sequentially connected, and the adjusting assembly is arranged on the purification system, the synthesis system and the liquefaction system;
the advanced control system for preparing the liquefied natural gas comprises a distributed control device and an advanced control device, wherein the distributed control device comprises a detection assembly and a distributed controller assembly which are in communication connection; the advanced control device comprises a real-time database, a model storage module, a prediction module and a control module which are in communication connection with each other; the model storage module stores purification model data, synthesis model data and liquefaction model data;
the real-time database and the control module are in communication connection with the distributed controller assembly; the detection component respectively acquires instant data of controllable variables of the purification system, the synthesis system and the liquefaction system, and transmits and stores the instant data to the real-time database; the real-time database stores historical data;
the prediction module can predict the change trend of the controllable variable in a preset time according to the purification model data, the synthesis model data, the liquefaction model data and the historical data;
the control module can calculate the optimal operation amount for the adjusting assembly according to the change trend and a preset ideal value and transmit the optimal operation amount to the distributed controller assembly;
and the distributed controller component adjusts the adjusting component according to the optimal operation amount so that the controllable variable works at the preset ideal value.
2. The advanced lng production control system of claim 1, wherein the advanced control apparatus further comprises a feedback correction module; the feedback correction module is respectively in communication connection with the real-time database, the model storage module, the prediction module and the control module;
and the feedback correction module corrects the purification model data, the synthesis model data and the liquefaction model data according to the instant data and the change trend.
3. The advanced control system for liquefied natural gas production according to claim 1, wherein the detection module includes a first detection module, a second detection module, and a third detection module;
the first detection assembly can acquire first instant data of a first controllable variable of the purification system, and transmits and stores the first instant data in the real-time database;
the second detection component can acquire second instant data of a second controllable variable of the synthesis system, and transmit and store the second instant data in the real-time database;
the third detection assembly can acquire third instant data of a third controllable variable of the liquefaction system, and the third instant data is transmitted and stored in the real-time database.
4. The advanced lng preparation control system of claim 3, wherein the control module comprises a purge controller, a synthesis controller, and a liquefaction controller;
the regulating assembly comprises a first regulating assembly arranged in the purification system, a second regulating assembly arranged in the synthesis system and a third regulating assembly arranged in the liquefaction system;
the prediction module can predict a first change trend of the first controllable variable in the preset time according to the first instant data, the purification model data and the historical data; the purge controller is capable of calculating a first optimum operation amount for the first adjusting component based on the first tendency of change and the predetermined ideal value;
the prediction module is further capable of predicting a second change trend of the second controllable variable within the preset time according to the second instant data, the synthetic model data and the historical data; the synthesizing controller is capable of calculating a second optimum operation amount for the second adjusting component based on the second tendency of change and the predetermined ideal value;
the prediction module is further capable of predicting a third change trend of the third controllable variable within the preset time according to the third instant data, the liquefaction model data and the historical data; the liquefaction controller may be configured to calculate a third optimum operation amount for the third regulation component based on the third tendency of change and the predetermined ideal value.
5. The advanced lng preparation control system of claim 4, wherein the first regulating component comprises at least a first valve at an inlet of the purification system, a second valve at an outlet of the purification system;
the first detection assembly at least comprises a first temperature detector and an oxygen content detector of the outlet of the purification system;
the purge model data is control model data of a set quantity of the first adjusting component to a detected quantity of the first detecting component.
6. The advanced lng preparation control system of claim 4, wherein the second regulating component comprises at least a third valve disposed at an inlet of the synthesis system, a fourth valve of the synthesis system;
the second detection assembly comprises at least a second temperature detector at the inlet of the synthesis system, a third temperature detector at the outlet of the synthesis system;
the synthetic model data is control model data of the set quantity of the second adjusting component to the detected quantity of the second detecting component.
7. The advanced lng preparation control system of claim 4, wherein the third regulating component comprises at least a fifth valve disposed at an inlet of the liquefaction system, a sixth valve disposed at an outlet of the liquefaction system;
the third detection assembly at least comprises a fourth temperature detector, a density detector and a pressure detector which are arranged in the liquefaction system;
the liquefaction model data is control model data of the set quantity of the third regulating module to the detected quantity of the third detecting module.
8. The advanced lng preparation control system of claim 2, wherein the distributed controller assembly comprises a distributed controller, a manipulation device and a display device; the control equipment and the display equipment are connected with the distributed controller.
9. The advanced control system for liquefied natural gas production according to claim 1, further comprising a first communication device, a second communication device, and an OPC server; the distributed controller assembly communicates with the OPC server via the first communication device and the control module communicates with the OPC server via the second communication device.
10. An LNG production system comprising the advanced LNG production control system according to any one of claims 1 to 9.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112783034A (en) * | 2020-12-30 | 2021-05-11 | 乔治洛德方法研究和开发液化空气有限公司 | Control system and control method of air separation device |
| CN114748975A (en) * | 2022-04-24 | 2022-07-15 | 国家电网有限公司 | Online purifying device and system for insulating gas |
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2020
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112783034A (en) * | 2020-12-30 | 2021-05-11 | 乔治洛德方法研究和开发液化空气有限公司 | Control system and control method of air separation device |
| CN112783034B (en) * | 2020-12-30 | 2024-05-14 | 乔治洛德方法研究和开发液化空气有限公司 | Control system and control method of air separation device |
| CN114748975A (en) * | 2022-04-24 | 2022-07-15 | 国家电网有限公司 | Online purifying device and system for insulating gas |
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