阅读说明：本技术 一种lng供气单元低压控制系统 (Low-pressure control system of LNG (liquefied Natural gas) supply unit ) 是由 陆恒 吴晓明 高丽燕 张佳妮 屈继强 刘海莹 于 2020-07-08 设计创作，主要内容包括：本发明公开了一种LNG供气单元低压控制系统,包括：压缩机模块,其包括若干个压缩机,每一所述压缩机设有一PLC控制柜,所述PLC控制柜用于对若干个压缩机的并联或单台的运行状态的逻辑控制；通信模块；监测控制模块,所述监测控制模块通过所述通信模块与每一所述PLC控制柜连接；所述监测控制模块用于对所述压缩机进行监测。本发明实现了对天然气进行监测与控制的目的。(The invention discloses a low-pressure control system of an LNG gas supply unit, which comprises: the compressor module comprises a plurality of compressors, each compressor is provided with a PLC (programmable logic controller) cabinet, and the PLC cabinets are used for logically controlling the parallel connection of the compressors or the running state of a single compressor; a communication module; the monitoring control module is connected with each PLC control cabinet through the communication module; the monitoring control module is used for monitoring the compressor. The invention realizes the purpose of monitoring and controlling the natural gas.)

1. A LNG gas supply unit low pressure control system, comprising:

the compressor module comprises a plurality of compressors, each compressor is provided with a PLC control cabinet,

the PLC control cabinet is used for carrying out logic control on the parallel connection of a plurality of compressors or the operation state of a single compressor;

a communication module;

the monitoring control module is connected with each PLC control cabinet through the communication module;

the monitoring control module is used for monitoring the compressor.

2. The LNG supply unit low pressure control system of claim 1, wherein the monitoring control module is configured to select an operating mode of each of the compressors.

3. The system for low pressure control of an LNG supply unit according to claim 2, wherein each of the compressors operates in three modes: master mode, slave mode and stand-alone mode.

4. A system for low pressure control of an LNG supply unit as recited in claim 3, wherein said monitoring and control module is adapted to determine the operating status of each of said compressors.

5. The LNG supply unit low pressure control system of claim 4, wherein the operating condition is obtained by receiving: zero load bit signal, full load bit signal, running signal and fault signal of the compressor;

the system comprises an input exit signal, a starting signal of a master-slave mode, a stopping signal of the master-slave mode, a single machine starting signal, a single machine stopping signal, an ESD emergency stopping signal and an interlocking stopping signal of each compressor.

6. The LNG supply unit lp control system of claim 1, wherein the inlet end of each of said compressors in said compressor module is fed with natural gas, and the outlet end thereof is connected to the corresponding dual-fuel engine test-run station in the plant through an automatic regulating valve.

7. The system of claim 1, wherein an interface control module is connected to the monitoring control module, and the interface control module is configured to control an operation mode of each of the compressors in a human-computer interaction manner and display monitoring data monitored by the monitoring control module.

8. The LNG supply unit low pressure control system of claim 7, wherein the interface manipulation module includes a simulation interface with field devices including three mode selection of the compressor and switching of the state of the self-regulating valve and a process interface;

the process interface is used for displaying the monitoring data;

the monitoring data comprises real-time data dynamic curves of the pressure, the temperature, the liquid level, the natural gas concentration and the flow of the monitored compressor;

each real-time data dynamic curve is displayed in an independent window, data needing to be displayed is added or deleted, real-time display of 1-20 channel data is supported at the same time, and the data are distinguished by different color curves.

9. The LNG supply unit low pressure control system of claim 8, further comprising: and the data printing module is connected with the monitoring control module and used for recording, saving and printing the monitoring data on the corresponding time point according to a preset time interval.

10. The system for low pressure control of LNG gas supply units according to claim 1, wherein a security module is connected to the monitoring control module, the security module is provided with a serial number of the memory card or all modules, and when the program block to be executed is not linked to the serial number of the corresponding memory card or all modules, the program block to be executed cannot be executed.

Technical Field

The invention relates to the technical field of natural gas supply, in particular to a low-pressure control system of an LNG (liquefied natural gas) supply unit.

Background

LNG gas supply low pressure control system is often applied to boats and ships trade and city natural gas supply engineering. As a novel energy source, natural gas has lower price compared with energy sources such as diesel oil and the like, and the emission of harmful substances and particulate matters is bound to be greatly varied for a long time in the future. However, natural gas itself has a certain risk of being ignited when the concentration in the air reaches 5% -15%, and thus explosion occurs. When leakage occurs in the presence of LNG (liquefied natural gas), it may cause frostbite to human bodies in contact. In order to ensure the safety of the related natural gas engineering, the natural gas must be monitored and controlled. Therefore, it is very important to develop a low-pressure system of an LNG supply unit.

Disclosure of Invention

The invention aims to provide a low-pressure system of an LNG (liquefied natural gas) supply unit, which aims to realize the monitoring and control of natural gas.

In order to achieve the above purpose, the invention is realized by the following technical scheme:

an LNG supply unit low pressure control system comprising: the compressor module comprises a plurality of compressors, each compressor is provided with a PLC (programmable logic controller) cabinet, and the PLC cabinets are used for logically controlling the parallel connection of the compressors or the running state of a single compressor; a communication module; the monitoring control module is connected with each PLC control cabinet through the communication module; the monitoring control module is used for monitoring the compressor.

Optionally, the monitoring control module is configured to select an operation mode of each of the compressors.

Optionally, each of the compressors has the following three operation modes: master mode, slave mode and stand-alone mode.

Optionally, the monitoring control module is configured to determine an operation state of each of the compressors.

Optionally, the operating state is obtained by receiving the following signals: zero load bit signal, full load bit signal, running signal and fault signal of the compressor; the system comprises an input exit signal, a starting signal of a master-slave mode, a stopping signal of the master-slave mode, a single machine starting signal, a single machine stopping signal, an ESD emergency stopping signal and an interlocking stopping signal of each compressor. And the air inlet end of each compressor in the compressor module is filled with natural gas, and the air outlet end of the compressor module is connected with the corresponding test bed of the dual-fuel engine in the workshop through an automatic regulating valve.

Optionally, in this embodiment, an interface control module is connected to the monitoring control module, and the interface control module is configured to control a working mode of each compressor in a human-computer interaction manner and display monitoring data obtained by monitoring of the monitoring control module.

Optionally, the interface control module includes a simulation interface with a field device and a process interface, and the simulation interface with the field device includes three modes of selection of the compressor and switching of the state of the automatic regulating valve; the process interface is used for displaying the monitoring data; the monitoring data comprises real-time data dynamic curves of the pressure, the temperature, the liquid level, the natural gas concentration and the flow of the monitored compressor; each real-time data dynamic curve is displayed in an independent window, data needing to be displayed is added or deleted, real-time display of 1-20 channel data is supported at the same time, and the data are distinguished by different color curves.

Optionally, the method further comprises: and the data printing module is connected with the monitoring control module and used for recording, saving and printing the monitoring data on the corresponding time point according to a preset time interval.

Optionally, the security module is connected to the monitoring control module, the security module is provided with a serial number of the memory card or all modules, and when the program block to be run is not linked to the serial number of the corresponding memory card or all modules, the program block to be run cannot be run.

The invention has at least one of the following advantages:

the LNG gas supply unit low-pressure control system provided by the invention provides direct or indirect parameter monitoring (monitoring data), electromechanical equipment control and automatic safety protection functions for a natural gas supply system, and realizes man-machine information interaction. The core equipment of the natural gas supply system is two sets of compressors (skid-mounted natural gas compressors), and the low-pressure control system of the LNG gas supply unit provided by the invention realizes the control, monitoring and security of the compressors by communicating with a PLC control cabinet of the compressors and connecting the compressors with hard wires. The purpose of monitoring and controlling the natural gas of the natural gas supply system is achieved.

Drawings

Fig. 1 is a block diagram illustrating a low-pressure control system of an LNG supply unit according to an embodiment of the present invention;

fig. 2 is a block diagram of a communication module of a low-pressure control system of an LNG gas supply unit according to an embodiment of the present invention.

Detailed Description

The low pressure control system of the LNG supply unit according to the present invention will be described in detail with reference to fig. 1 and 2 and the following detailed description. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are all used in a non-precise scale for the purpose of facilitating and distinctly aiding in the description of the embodiments of the present invention. To make the objects, features and advantages of the present invention comprehensible, reference is made to the accompanying drawings. It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for matching with the disclosure of the specification, so as to be understood and read by those skilled in the art, and are not used to limit the implementation conditions of the present invention, so that the present invention has no technical significance, and any structural modification, ratio relationship change or size adjustment should still fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Referring to fig. 1 and fig. 2, the present embodiment provides a low pressure control system for an LNG supply unit, including: the compressor module 100 comprises a plurality of compressors, each compressor is provided with a PLC (programmable logic controller) cabinet, and the PLC cabinets are used for controlling the parallel connection of the plurality of compressors or the running state, the consistent regulation and the main logic of signal interlocking; a communication module 200; the monitoring control module 300 is connected with each PLC control cabinet through the communication module 200; the monitoring control module 300 is used for monitoring the compressor.

The compressor module 100 compresses the supplied gas by the compressor to increase the pressure to a pressure value set by a low pressure control system of the LNG supply unit.

The supervisory control module 300 is configured to select an operating mode for each of the compressors. The operation modes of each compressor are as follows: master mode, slave mode and stand-alone mode. The monitoring control module 300 is used for judging the operation state of each compressor. The monitoring control module 300 mainly comprises a PLC control cabinet and an upper computer CPU.

The operating state is obtained by receiving the following signals: zero load bit signal, full load bit signal, running signal and fault signal of the compressor; the system comprises an input exit signal, a starting signal of a master-slave mode, a stopping signal of the master-slave mode, a single machine starting signal, a single machine stopping signal, an ESD emergency stopping signal and an interlocking stopping signal of each compressor.

Specifically, the monitoring control module 300 uses a PLC control cabinet to communicate with the compressors via the communication module and the hard wire, and controls the main logics of starting and stopping, load adjustment, signal interlocking, and the like of a single or two compressors (connected in parallel). And outputting and receiving key signals of the compressor, selecting the working mode of the compressor, and judging the running state of the compressor. The main monitoring points are: a zero load bit signal, a full load bit signal, an operation signal, a fault signal, etc. of the compressor. The main control security points are as follows: the system comprises a compressor input exit signal, a starting signal (master-slave mode), a stopping signal (master-slave mode), a single machine starting signal, a single machine stopping signal, an ESD emergency stopping signal, a linkage stopping signal and the like. The signals are connected with the PLC control cabinet through hard wires, and other compressed signals are collected through a MODBUS communication mode.

The inlet end of each compressor in the compressor module 100 is filled with natural gas, and the outlet end of the compressor module is connected with the corresponding test run platform of the dual-fuel engine in the workshop through an automatic regulating valve.

The communication module 200 mainly comprises an IM155-5PN, a MODBUS communication protocol and the like, wherein the communication interfaces of the IM155-5PN and the like and the usable MODBUS communication protocol help the system to link the modules through the transmission of signals among the modules. The method specifically comprises the following steps: switches and various types of interfaces to the switches, such as: I/O ports for AO, AI, DO, and DI modules.

The low-pressure control system of the LNG gas supply unit provided by this embodiment has the following main working processes: the compressor module compresses the natural gas, increases the pressure of a natural gas supply system until reaching a set value, and outputs the pressure to each dual-fuel engine test-run platform of the workshop after being processed by the oil removing, water removing and cooling device. All set up automatically regulated valve before every platform position advances the host computer, when the flow pressure of host computer demand exceeded the maximum control range of compressor, and can not satisfy the host computer operating mode demand, advance quick-witted pressure through the aperture change of adjustment automatically regulated valve. Meanwhile, the control, monitoring and security of the compressor are realized through communication and hard wire connection with the compressor control cabinet, field data are collected and processed, and simultaneous air supply of a single station or a plurality of stations is realized. The low-pressure control system of the LNG gas supply unit can select the station needing gas supply before operation, and control and monitor the compressor of the selected station.

And the interface control module 400 is connected with the monitoring control module 300, and the interface control module 400 is used for controlling the working mode of each compressor in a man-machine interaction manner and displaying the monitoring data obtained by the monitoring control module 300. The interface control module 400 is composed of an upper computer operation control interface.

The interface manipulation module 400 includes a simulation interface with field devices including three modes selection of the compressor and switching of the state of the self-regulating valve and a process interface; the process interface is used for displaying the monitoring data; the monitoring data comprises real-time data dynamic curves of the pressure, the temperature, the liquid level, the natural gas concentration and the flow of the monitored compressor; each real-time data dynamic curve is displayed in an independent window, data needing to be displayed is added or deleted, real-time display of 1-20 channel data is supported at the same time, and the data are distinguished by different color curves.

Specifically, the interface control module 400 controls the system interface to have a simulation interface and a process interface of the field device (in a manual mode, the start and stop of a switch can be performed through a human-computer interface), and includes three modes of selection of the compressor (each compressor has three operation modes of a master operation mode, a slave operation mode and a single operation mode), switching of the state of a regulating valve, and real-time data dynamic curves of pressure, temperature, liquid level, gas concentration, flow and the like (the curves can be displayed in an independent window, data needing to be displayed is added or deleted, the real-time display of 20 channel data can be supported at the highest time, and the curves are distinguished by different color curves.

Optionally, this embodiment further includes: and a data printing module 600 connected to the monitoring control module 300, for recording, saving and printing the monitoring data at the corresponding time point according to a preset time interval. The data printing module 600 is mainly composed of a printer and a display.

The data printing module 600 displays the collected monitoring data, including pressure, temperature, liquid level, gas concentration and flow rate. The recorded monitoring data can be printed out by a printer in the console (data at corresponding time points are stored according to set time intervals, the recording starting condition is an air supply system running signal, and the recording stopping condition is an air supply system stopping signal).

Optionally, this embodiment further includes: and the security module is connected with the monitoring control module 300, is provided with a serial number of the memory card or all modules, and cannot run the program block which needs to run when the program block which needs to run is not linked to the serial number of the corresponding memory card or all modules.

The security module mainly comprises a SIMATIC memory card or the serial number of the module, and the like. : the used PLC controller has the copy protection function. The user program block is linked to the serial number of the SIMATIC or module. If there is no corresponding SIMATIC memory card or module, the user program cannot run (1. Access protection extended access protection provides comprehensive protection against unauthorized configuration changes.2. authorization level can be used to assign different permissions to different groups of users.3. data transferred to the CPU can be protected from unauthorized manipulation). The safety level and the processing speed are higher than those of the relatively independent security function hardware equipment and the control and monitoring function hardware equipment of the control and monitoring system module, and safety guarantee is provided for the occurrence of emergency. Meanwhile, the security module provides an independent indication interface of security signals and a button resetting and emergency stopping function, and great security guarantee is provided for the whole system.

The power module 500 is configured to supply power to a low-voltage control system of an LNG supply unit according to this embodiment. The power module 500 mainly includes a power supply system and a UPS power supply. The power distribution cabinet provided by a user supplies power to the system and is provided with the UPS, and when power failure occurs, the power supply of the UPS starts to supply power to the system.

The low-pressure control system of the LNG gas supply unit provided by this embodiment provides direct or indirect parameter monitoring (monitoring data), electromechanical device control, and automatic safety protection functions for the natural gas supply system, and realizes human-computer information interaction. The core equipment of the natural gas supply system is two sets of compressors (skid-mounted natural gas compressors), and the low-pressure control system of the LNG gas supply unit provided by the invention realizes the control, monitoring and security of the compressors by communicating with a PLC control cabinet of the compressors and connecting the compressors with hard wires. The purpose of monitoring and controlling the natural gas of the natural gas supply system is achieved.

Specific control security and monitoring requirements for the compressor: the main logics of parallel connection of two compressors or single start-stop, load regulation, signal interlocking and the like are realized by the compressor control cabinet. The control security system only needs to output and receive key signals of the compressor, select the working mode of the compressor, control the total start and stop of the compressor and judge the running state of the compressor. The main monitoring points (single compressor) are: a zero load bit signal, a full load bit signal, an operation signal, a fault signal, etc. of the compressor. The main control security points (single compressor) are: the system comprises a compressor input exit signal, a starting signal (master-slave mode), a stopping signal (master-slave mode), a single machine starting signal, a single machine stopping signal, an ESD emergency stopping signal, an interlocking stopping signal and the like, wherein the signals are connected with a compressor control cabinet through hard wires. Other compressor signals can be acquired through MODBUS communication, and data and communication protocols to be acquired are provided by buyers. In addition, the system should have the function of selecting the operation modes of the compressors, and each compressor has three operation modes of a master operation mode, a slave operation mode and a single machine operation mode. Before the system runs each time, the running mode of each compressor needs to be selected. And when the operator selects one of the two modes as the master mode, the system automatically switches the other mode into the slave mode. Functionally, the natural gas supply system pressurizes the natural gas of the municipal pipeline to a certain pressure through the compressor module and supplies the pressurized natural gas to the test run table positions of each dual-fuel engine in a workshop, and the natural gas is subjected to accurate pressure regulation, metering and emergency cut-off by the pressure regulating valve before entering the workshop. And the field data is collected and processed, the control and monitoring of relevant equipment and parameters in the system are realized, and the requirement of simultaneously supplying gas for one or more stations is realized. The control system can select the station needing air supply before operation and control and monitor the relevant equipment of the selected station. The design of the acquisition control box can effectively distinguish intrinsic safety signals from other signals.

The system provided in this embodiment reserves the functionality of the distributed system and should communicate over a common and redundant network.

In summary, the system provided in this embodiment connects the console module, the monitoring control module, the compressor module, the interface control module, and the security module through the communication protocol of the communication module. The power module provides power support to the entire system. The interface control module is an outline of the whole system, the interface control module is paired with the console module, and a user changes attributes in the interface control module through the display so as to change the states of other modules, such as the compressor module and the monitoring control module. The monitoring control module can change the state of the compressor module. The whole system realizes all required functions through configuration of I/O ports of AO, AI, DO and DI modules, connection of communication interfaces and the like.

The CPU 1515-2PN has two interfaces with the same IP address, together forming a fieldbus level interface (switch input function). The second PROFINET interface has a port with its own IP address for integration into the network. And the upper computer reads and sends data according to different IP addresses through the switch.

Specifically, the CPU 1515-2PN expands two interface modules IM155-5PN, so that the CPU can expand more communication modules. The upper computer directly sends out an operation command, and the lower computer PLC analyzes the command into a corresponding time sequence signal to directly control a corresponding device (the command of the upper computer analyzed by the CPU is a command for running the device through the configured DO/AO). The CPU sends signals fed back by configured AI/DI (AI is configured to current signals fed back by some flow meters, DI is configured to switching value signals fed back by some valve switches) to the upper computer, and the upper computer analyzes the sent signals and displays data and the on-off state of the equipment.

In addition, the functional modules in the embodiments herein may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.