Pressure control device, method and system for coexistence of different types of full-capacity tanks

Abstract

The invention discloses a pressure control device, method and system for coexistence of different types of full-capacity tanks, and the device comprises a plurality of full-capacity tanks, each full-capacity tank is provided with a first pressure detector, and each full-capacity tank is connected with an input pipe through a valve group; any full-capacity tank is connected with the torch and the output pipe, and a first control valve is arranged between the torch and the full-capacity tank; the first control valve and the valve group of any full-capacity tank are respectively connected with a controller, and the controller controls the opening and closing of the first control valve and the valve group; the two full-capacity tanks with different design pressures share one output pipe, a pressure protection system is arranged on the output pipe between the two full-capacity tanks, and the pressure protection system comprises at least one first stop valve and a second pressure detector which are connected with a controller; in response to a trigger signal of the second pressure detector, the controller controls the first stop valve to be opened and closed. And on the premise that safe and stable operation of a station yard is guaranteed, the full-capacity tanks with different design pressures can operate at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of full containment LNG tanks, and particularly to a pressure control device, method and system for the coexistence of different types of full containment tanks. Background Art

[0002] LNG (liquefied natural gas) is a high-quality energy source with wide applications. Due to its characteristics such as high calorific value, high efficiency, and low pollution, it is widely used in various fields of national economy and people's livelihood, and its energy proportion is gradually increasing. As the most important storage equipment in LNG receiving terminals and liquefaction plants, full containment LNG tanks undertake functions such as ship unloading, low-pressure external transmission, loading and unloading of trucks, etc. They are characterized by high cost, long construction period, complex control, etc. And the pressure control of full containment LNG tanks is also the key and difficult point of its control system.

[0003] Currently, the commonly used types of large full containment LNG tanks are double-metal wall fully enclosed LNG tanks and prestressed concrete fully enclosed LNG tanks. Most domestic LNG receiving terminals adopt the same type of LNG tanks, and the design pressure and operating pressure of the full containment tanks are the same, which is convenient for the control of the full containment tanks and the operation management of the entire station. With the development of the LNG industry, the owner's construction demand for the diversification of LNG tank types has emerged. The double-metal full containment tank has become one of the preferred tank types in the domestic engineering construction industry due to its advantages such as short construction period and low investment. For renovation and expansion projects, it has also become a reality to use double-metal wall and prestressed concrete LNG tanks simultaneously in the same LNG receiving terminal. The operating pressure and design pressure of the double-metal full containment tank are relatively low (usually 18 - 21 kPaG), resulting in the design pressure of the double-metal full containment tank being less than that of the prestressed concrete full containment tank (usually 23 - 29 kPaG). Therefore, when the two different LNG full containment tanks operate simultaneously, it will pose a safety hazard to the double-metal full containment tank with a lower design pressure. Therefore, from the perspective of the design safety principle in the prior art, two sets of independent BOG (boil-off gas) pipelines, BOG compressors, flare systems and make-up gas pipelines need to be set for the double-metal full containment tank and the prestressed concrete full containment tank, which greatly increases the construction cost of the LNG receiving terminal and also adds difficulties and safety hazards to the operation management of the station.

[0004] Therefore, there is an urgent need for a control device, method and system that can enable the simultaneous operation of two different LNG full containment tanks. Summary of the Invention

[0005] By providing a pressure control device, method and system for the coexistence of different types of full containment tanks in an embodiment of the present invention, the technical problem in the prior art that different design pressure full containment tanks will pose a safety hazard to the double-metal full containment tank with a lower design pressure when they are connected and operate simultaneously is solved, and the technical effect of enabling the simultaneous operation of different design pressure full containment tanks is achieved on the premise of ensuring the safe and stable operation of the station.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention discloses a pressure control device for coexistence of different types of full containment tanks, including:

[0008] A plurality of full containment tanks, and a first pressure detector is provided on any one of the above-mentioned full containment tanks to detect the pressure inside the full containment tank;

[0009] Any one of the above-mentioned full containment tanks is connected to an input pipe through a valve group, and the valve group is used to control the gas input into the full containment tank;

[0010] Any one of the above-mentioned full containment tanks is respectively connected to a flare and an output pipe, and a first control valve is provided between the flare and the full containment tank; the first control valve and the valve group of any one of the above-mentioned full containment tanks are respectively connected to a controller, and the controller controls the opening and closing of the first control valve and the valve group in response to a trigger signal corresponding to the first pressure detector;

[0011] Two full containment tanks with different design pressures share a single output pipe, and a pressure protection system is provided on the output pipe between the two full containment tanks. The pressure protection system includes at least one first cut-off valve and a second pressure detector connected to the controller; in response to the trigger signal of the second pressure detector, the controller controls the opening and closing of the first cut-off valve.

[0012] Optionally, the pressure protection system includes a plurality of the second pressure detectors provided at multiple positions on the output pipe; the controller controls the opening and closing of the plurality of first cut-off valves in response to trigger signals issued by a preset number of the second pressure detectors.

[0013] Optionally, the device further includes a third pressure detector provided on the output pipe and a second control valve connected in series with the first cut-off valve; the third pressure detector and the second control valve are respectively connected to the controller, and the controller controls the opening degree of the second control valve according to the value of the third pressure detector.

[0014] Optionally, the valve group includes a third control valve and a second cut-off valve connected in series, and the third control valve is connected to the controller.

[0015] Optionally, a third cut-off valve is provided on the output and / or input pipeline of any one of the above-mentioned full containment tanks.

[0016] Optionally, among the two full containment tanks with different design pressures, the full containment tank with the smallest design pressure is arranged closest to the output end of the output pipe.

[0017] Second aspect, the present invention discloses a pressure control method for coexistence of different types of full containment tanks, including: a pressure control device for coexistence of different types of full containment tanks

[0018] The above method includes:

[0019] Preset the negative pressure air supplement set value and overpressure set value of two full containment tanks with different design pressures; among them, the first overpressure set value of the full containment tank closest to the output end of the above output pipe is less than the second overpressure set value of the other full containment tank;

[0020] When all full containment tanks are operating normally, close all the above first control valves and the above valve group, and open the remaining valves;

[0021] When any one of the above full containment tanks reaches the preset negative pressure air supplement set value, in response to the signal triggered by the corresponding above first pressure detector, control the corresponding above valve group to open and perform air supplement;

[0022] When the pressure of the output pipe is greater than the above first overpressure set value, in response to the trigger signal of the above second pressure detector, control the above first cut-off valve to close; detect the pressures in the two above full containment tanks with different design pressures, and when the detected pressure value in any one of the above full containment tanks is greater than the corresponding overpressure set value, open the corresponding first control valve to discharge the gas to the above flare.

[0023] Optionally, the step of controlling the above first cut-off valve to close specifically includes:

[0024] Among multiple above second pressure detectors, when a preset number of the above second pressure detectors detect that the pressure in the output pipe is greater than the first overpressure set value, control the above first cut-off valve to close.

[0025] Optionally, it includes a third pressure detector arranged on the above output pipe and a second control valve connected in series with the above first cut-off valve; the above method further includes:

[0026] Preset the pressure stability value of the above output pipe;

[0027] According to the pressure on the output pipe monitored in real time by the third pressure detector, adjust the opening and closing degree of the above second control valve to maintain the pressure in the above output pipe to reach the above stability value.

[0028] Third aspect, the present invention discloses a pressure control system for coexistence of different types of full containment tanks, including:

[0029] A pressure threshold definition module for presetting the negative pressure air supplement set value and overpressure set value of two full containment tanks with different design pressures; among them, the first overpressure set value of the full containment tank closest to the output end of the above output pipe is less than the second overpressure set value of the other full containment tank;

[0030] A normal operation control module, which is used to close all the above-mentioned first control valves and the above-mentioned valve group and open the remaining valves when all the full-capacity tanks are operating normally;

[0031] An air supplement control module, which is used to control the opening of the corresponding valve group and perform air supplement in response to the signal triggered by the corresponding first pressure detector when any one of the above-mentioned full-capacity tanks reaches the preset negative pressure air supplement set value;

[0032] An overpressure control module, which is used to control the closing of the above-mentioned first cut-off valve in response to the trigger signal of the above-mentioned second pressure detector when the pressure of the output pipe is greater than the above-mentioned first overpressure set value; detect the pressures in the two above-mentioned full-capacity tanks with different design pressures, and when the detected pressure value in any one of the above-mentioned full-capacity tanks is greater than the corresponding overpressure set value, open the corresponding first control valve to discharge the gas to the above-mentioned flare.

[0033] One or more technical solutions provided in the present invention have at least the following technical effects or advantages:

[0034] In the technical solution of the present invention, pressure gauges are provided on two full-capacity tanks to monitor the internal pressure of the full-capacity tanks, and valves are provided on the input pipes of the two full-capacity tanks with different design pressures to control the injection amount according to the monitored pressure conditions in the full-capacity tanks. The two full-capacity tanks with different design pressures share one output pipe, and a pressure protection system is provided between the two full-capacity tanks. The pressure protection system opens the valve during injection to keep the two full-capacity tanks connected, improving the injection efficiency. When the pressure gauge monitors that the internal pressure of the full-capacity tank is overpressure, the pressure protection system closes the valve to isolate the two full-capacity tanks with different design pressures. Thus, the two full-capacity tanks can operate simultaneously, maintaining the pressures of the two full-capacity tanks within a reasonable range under normal conditions, and avoiding potential safety hazards to the bimetallic full-capacity tank with a lower design pressure when two full-capacity tanks with different design pressures operate simultaneously. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 It is a schematic structural diagram of a pressure control device for coexistence of different types of full-capacity tanks provided by the present invention;

[0037] Figure 2 It is a flowchart of a pressure control method for coexistence of different types of full-capacity tanks provided by the present invention;

[0038] Figure 3Schematic structural diagram of a pressure control system for coexistence of different types of full containment tanks provided by the present invention. Detailed implementation manners

[0039] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. Components of the embodiments of the present invention generally described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0041] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not require further definition and explanation in subsequent drawings.

[0042] In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "arranged" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0043] It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations on the technical solutions of the present application. Without conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0044] In the embodiments of the present invention, there is provided a pressure control device for coexistence of different types of full containment tanks as Figure 1 shown, including:

[0045] A plurality of full containment tanks, and a first pressure detector is provided on any one of the full containment tanks to detect the pressure inside the full containment tank. Refer to Figure 1The full containment tanks T01, the first pressure detector P1, the full containment tank T02 and the first pressure detector P2 therein. The first pressure detector is designed to monitor the pressure inside the full containment tank, so as to control the valve according to the pressure subsequently.

[0046] Any full containment tank is connected to the input pipe through a valve group, and the valve group is used to control the gas input into the full containment tank. Refer to Figure 1 The shut-off valve XV04 and the control valve PCV02, the shut-off valve XV03 and the control valve PCV03 in [[ ]]; among them, each full containment tank is connected in series with a shut-off valve and a control valve, and the reason is to achieve better fluid control and safety protection. Specifically, the shut-off valve is designed to cut off the flow of the pipeline medium. When it is necessary to stop the fluid transfer, the shut-off valve can be quickly closed to avoid accidents and ensure the safety of personnel and equipment. The control valve is designed to control the flow rate and pressure of the pipeline medium. By adjusting the opening of the control valve, precise control of the medium flow rate can be achieved, so as to meet different working conditions. Two valves are set, namely the control valve and the shut-off valve, where the control valve is used for the control of the DCS system, and the shut-off valve is used for the safety interlock of the SIS system. At the same time, the setting of the two valves can also achieve the selection of the other one for control after one of them is damaged, improving the safety.

[0047] Any full containment tank is respectively connected to the flare and the output pipe, and a first control valve is provided between the flare and the full containment tank; the first control valve and the valve group of any full containment tank are respectively connected to the controller, and the controller controls the opening and closing of the first control valve and the valve group in response to the trigger signal of the corresponding first pressure detector. Among them, the connection between the full containment tank and the flare is to release the evaporated gas exceeding the bearing capacity of the full container, and use the flare to safely burn these excess evaporated gases, thereby reducing the pressure in the storage tank and avoiding the damage of the storage tank caused by excessive pressure in the storage tank, resulting in huge economic losses and safety hazards. The connection between the full containment tank and the output pipe (i.e., the BOG main pipe) is to transport the evaporated gas to the using equipment, such as transporting it to the recondenser for recycling, or transporting it to the fuel gas system for combustion utilization, etc. In addition, a first control valve is provided between the flare and the full containment tank, please refer to Figure 1 The control valves PCV05 and PCV04, the purpose is to avoid the direct entry of the evaporator into the flare when the pressure in the full containment tank is not overpressure, thus causing waste. And the controller is used to realize the automatic monitoring of the pressure in the full container. When it is in negative pressure, the valve group is opened (such as Figure 1 PCV02 and XV04, XV03 and PCV03 in [[ ]]), and when it is overpressure, the first control valve is opened.

[0048] Two full containment tanks with different design pressures share a single output pipe. A pressure protection system is provided on the output pipe located between the two full containment tanks. The pressure protection system includes at least one first shut-off valve connected to a controller and a second pressure detector; in response to a trigger signal from the second pressure detector, the controller controls the opening and closing of the first shut-off valve.

[0049] Among them, the two full containment tanks with different design pressures can be a bimetallic full containment tank and a prestressed concrete full containment tank. The operating pressure and design pressure of the bimetallic full containment tank are 18 - 21 kPaG, and the design pressure of the prestressed concrete full containment tank is 23 - 29 kPaG. And two full containment tanks with different design pressures share a single output pipe (i.e., the BOG main pipe, as Figure 1 shown). To avoid potential safety hazards to the full containment tank with a lower design pressure when the two full containment tanks with different design pressures are operating simultaneously. A pressure protection system is provided on the output pipe located between the two full containment tanks. The pressure protection system detects the pressure inside the output pipe based on the second pressure detectors P6, P7, and P8. When the pressure exceeds the limit, the first shut-off valves XV05 and XV06 are used to completely cut off the BOG main pipe to isolate the two full containment tanks, so as to achieve the purpose of protecting the low-pressure full containment tank.

[0050] Furthermore, the pressure protection system includes multiple second pressure detectors provided at multiple positions on the output pipe; the controller controls the opening and closing of the multiple first shut-off valves in response to trigger signals issued by a preset number of second pressure detectors.

[0051] It should be noted that the reason for setting multiple second pressure detectors P6, P7, and P8 is to provide more comprehensive pressure monitoring and control. The multiple second pressure detectors are distributed at different positions on the pipeline to more accurately measure the pressure changes inside the pipeline. The controller detects the three second pressure detectors P6, P7, and P8. As long as two of them reach the threshold value, the multiple first shut-off valves can be controlled to close to cut off the two full containment tanks. Thus, it can avoid system malfunction caused by the failure or false alarm of a single second pressure detector. In addition, setting multiple first shut-off valves XV05 and XV06 can be used as backups for each other to improve the reliability of the system. If one of the valves fails or gets stuck, the other valve can still work normally to ensure the closing of the pipeline and fluid control.

[0052] Furthermore, the device also includes a third pressure detector P5 provided on the output pipe and a second control valve PCV01 connected in series with the first shut-off valve; the third pressure detector and the second control valve are respectively connected to the controller, and the controller controls the opening and closing degree of the second control valve according to the value of the third pressure detector. Taking the bimetallic full containment tank T02 and the prestressed concrete full containment tank T01 as an example, as Figure 1As shown in the figure, the third pressure detector P5 is used to detect the pressure in the output pipe. When the pressure in the output pipe gradually reaches the pressure threshold of the bimetallic full containment tank T02 from the lowest value, the controller controls the second control valve PCV01 to gradually reduce the supply volume from the prestressed concrete full containment tank T01 to the bimetallic full containment tank T02, so as to avoid the inability to control the pressure in time when the bimetallic full containment tank T02 is about to be overpressured, ensuring the safe and stable operation of the bimetallic full containment tank T02 and improving the safety.

[0053] Furthermore, the valve group includes a third control valve and a second cut-off valve connected in series, and the third control valve is connected to the controller.

[0054] It should be noted that the reason for connecting a cut-off valve and a control valve in series on the pipeline is to achieve better fluid control and safety protection. Figure 1 In the figure, a valve group is provided on the input branch pipes of both full containment tanks. The prestressed concrete full containment tank T01 is controlled by the third control valve PCV02 and the second cut-off valve XV04, and the bimetallic full containment tank T02 is controlled by the third control valve PCV03 and the second cut-off valve XV03. Among them, the main function of the cut-off valve is to cut off the flow of the pipeline medium. When it is necessary to stop the fluid transfer, the cut-off valve can be quickly closed to avoid accidents and ensure the safety of personnel and equipment. The function of the control valve is to control the flow rate and pressure of the pipeline medium. By adjusting the opening of the control valve, precise control of the medium flow rate can be achieved, so as to meet different working conditions. By connecting the cut-off valve and the control valve in series, better fluid control and safety protection can be achieved.

[0055] Furthermore, a third cut-off valve is provided on the output and / or input pipeline of any full containment tank. Figure 1 In the figure, the output and / or input pipeline of the prestressed concrete full containment tank T01 is controlled by the third cut-off valve XV01, and the output and / or input pipeline of the bimetallic full containment tank T02 is controlled by the third cut-off valve XV02. The purpose is to control the boil-off gas in the full containment tank. When the equipment needs boil-off gas, the corresponding third cut-off valve is opened to release the boil-off gas. When it is not necessary to discharge the boil-off gas, the corresponding third cut-off valve is closed.

[0056] Furthermore, among the two full containment tanks with different design pressures, the full containment tank with the smallest design pressure is set closest to the output end of the output pipe.

[0057] It should be noted that because the fluid moves towards the outlet during the operation of the pipeline. The full containment tank located at the output end of the output pipe will be filled first, so its pressure is also the easiest to detect. Since the two full containment tanks are connected, if the full containment tank with a larger design pressure is filled first, it is likely to cause safety hazards. Therefore, the full containment tank with the smallest design pressure is set closest to the output end of the output pipe.

[0058] In an embodiment of the present invention, pressure gauges are provided on two full containment tanks to monitor the internal pressure of the full containment tanks, and valves are provided on the input pipes of the two full containment tanks with different design pressures. The injection volume is controlled according to the monitored pressure conditions in the full containment tanks. Two full containment tanks with different design pressures share a single output pipe, and a pressure protection system is provided between the two full containment tanks. When injecting, the pressure protection system opens the valve to keep the two full containment tanks connected, improving the injection efficiency. When the pressure gauge monitors that the internal pressure of the full containment tank is overpressure, the pressure protection system closes the valve to isolate the two full containment tanks with different design pressures. Thus, the two full containment tanks can operate simultaneously, maintaining the pressures of the two full containment tanks within a reasonable range under normal conditions, avoiding potential safety hazards to the bimetallic full containment tank with a lower design pressure when two full containment tanks with different design pressures are operating simultaneously, and improving safety.

[0059] In an embodiment of the present invention, there is provided a pressure control method for the coexistence of different types of full containment tanks as shown in Figure 2 Figure, and the method includes steps S101 to S102:

[0060] Step S101, preset the negative pressure air supplement set value and overpressure set value for two full containment tanks with different design pressures; among them, the first overpressure set value of the full containment tank closest to the output end of the output pipe is less than the second overpressure set value of the other full containment tank;

[0061] It should be noted that during the application of two full containment tanks with different design pressures, there are two operating conditions. One is that due to excessive extraction of the evaporated gas in the full containment tank by an external compressor, the full containment tank is in a negative pressure state; the other is that due to insufficient extraction capacity of the BOG evaporated gas compressor or reasons such as the full containment tank being heated, the amount of evaporated gas in the full containment tank is too large, resulting in overpressure of the full containment tank. Therefore, the air supplement set value and overpressure set value are preset for the two full containment tanks with different design pressures.

[0062] Step S1021, when all full containment tanks are operating normally, close all first control valves and valve groups, and open the remaining valves. Among them, when the full containment tank is operating normally, it means that fluid is being released from the full containment tank and no supplement is required. Therefore, close the valve groups PCV02 and XV04, and the valve groups PCV03 and XV03. It is also not necessary to burn using a flare, so close the first control valves PCV04 and PCV05.

[0063] Step S1022: When any full - volume tank reaches the preset negative - pressure air - replenishment set value, in response to the signal triggered by the corresponding first pressure detector, control the corresponding valve group to open and conduct air replenishment. Specifically, this step mainly uses the first pressure detector to detect the pressure in the full - volume tank to measure whether the fluid volume is low, so as to control the valve groups PCV02 and XV04 (or valve groups PCV03 and XV03) to replenish the corresponding full - volume tank. Specifically, the negative - pressure air - replenishment set value of the full - volume tank T01 is A01, and the negative - pressure air - replenishment set value of the full - volume tank T02 is A02. A01 and A02 can be the same or different. When P1 detects that the air pressure in the full - volume tank meets A01, open the valve groups XV04 and PCV02, and keep the states of the other valves unchanged; when P2 detects that the air pressure in the full - volume tank meets A02, open the valve groups XV03 and PCV03, and keep the states of the other valves unchanged; when both P1 and P2 reach their respective set values, open the valves XV04, PCV02, XV03, and PCV02, and keep the states of the other valves unchanged.

[0064] Step S1023: When the pressure of the output pipe is greater than the first over - pressure set value, in response to the trigger signal of the second pressure detector, control the first cut - off valve to close; detect the pressures in two full - volume tanks with different design pressures. When the pressure value detected in any full - volume tank is greater than the corresponding over - pressure set value, open the corresponding first control valve to discharge the gas to the flare.

[0065] It should be noted that when the full - volume tank is over - pressured due to insufficient extraction capacity of the BOG evaporative gas compressor or excessive heat in the full - volume tank, resulting in an excessive amount of evaporative gas in the full - volume tank, the two full - volume tanks need to be isolated, and the over - pressured evaporative gas needs to be transported to the flare. Specifically, assume that the over - pressure set value of the full - volume tank T01 is A03, the over - pressure set value of the full - volume tank T02 is A04, and the set values of the second pressure detectors P6, P7, and P8 are A04, and A04 < A03. When two of the detectors P6, P7, and P8 detect that the air pressure in the output pipe reaches the set value A04, the first cut - off valves XV05 and XV06 close; when the first pressure detector P2 detects that the air pressure in the full - volume tank meets A04, the first control valve PCV04 opens to discharge the over - pressured evaporative gas in the full - volume tank T02 to the flare; when the first pressure detector P1 detects that the air pressure in the full - volume tank meets A03, the first control valve PCV05 opens to discharge the over - pressured evaporative gas in the full - volume tank T01 to the flare.

[0066] Further, the step of controlling the first cut-off valve to close specifically includes: among multiple second pressure detectors, when a preset number of second pressure detectors detect that the pressure in the output pipe is greater than the first overpressure set value, controlling the first cut-off valve to close. Among them, the reason for setting multiple second pressure detectors P6, P7, and P8 is to provide more comprehensive pressure monitoring and control. By setting two of them to reach the threshold, the first cut-off valves XV05 and XV06 can be controlled to close, cutting off the two full containment tanks. This avoids system malfunction caused by the failure or false alarm of a single second pressure detector.

[0067] Further, it includes a third pressure detector arranged on the output pipe and a second control valve connected in series with the first cut-off valve; this method further includes: presetting the pressure stability value of the output pipe; according to the pressure on the output pipe monitored by the third pressure detector in real time, adjusting the opening and closing degree of the second control valve to maintain the pressure in the output pipe at the stability value.

[0068] It should be noted that during the control process of the output pipe (i.e., Figure 1 the BOG main pipe), the control of the opening and closing degree of the second control valve PCV01 mainly controls the fluid transported from the full containment tank T01 to the output pipe. Under the monitoring of the third pressure detector P5, when the pressure in the output pipe is about to reach the pressure stability value, the pressure delivery is gradually reduced to avoid sudden disconnection and impact, improving safety.

[0069] Based on the same inventive concept, the embodiment of the present invention provides a pressure control system for coexistence of different types of full containment tanks, as Figure 3 shown, including:

[0070] A pressure threshold definition module for presetting the negative pressure air supplement set value and overpressure set value of two full containment tanks with different design pressures; among them, the first overpressure set value of the full containment tank closest to the output end of the output pipe is less than the second overpressure set value of the other full containment tank;

[0071] A normal operation control module for closing all first control valves and valve groups and opening the remaining valves when all full containment tanks are operating normally;

[0072] An air supplement control module for controlling the corresponding valve group to open and perform air supplement in response to the signal triggered by the corresponding first pressure detector when any full containment tank reaches the preset negative pressure air supplement set value;

[0073] An overpressure control module for controlling the first cut-off valve to close in response to the trigger signal of the second pressure detector when the pressure of the output pipe is greater than the first overpressure set value; detecting the pressure in two full containment tanks with different design pressures, and opening the corresponding first control valve to discharge the gas to the flare when the detected pressure value in any full containment tank is greater than the corresponding overpressure set value.

[0074] The present invention is described with reference to the flowcharts and / or block diagrams of methods and systems according to embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce means for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0075] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0076] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A pressure control device for the coexistence of different types of full containment tanks, characterized in that, the device comprises: a plurality of full containment tanks, and a first pressure detector is provided on any one of the full containment tanks to detect the pressure inside the full containment tank; any one of the full containment tanks is connected to an input pipe through a valve group, and the valve group is used to control the gas input into the full containment tank; any one of the full containment tanks is respectively connected to a flare and an output pipe, and a first control valve is provided between the flare and the full containment tank; the first control valve and the valve group of any one of the full containment tanks are respectively connected to a controller, and the controller controls the opening and closing of the first control valve and the valve group in response to a trigger signal corresponding to the first pressure detector; two full containment tanks with different design pressures share one output pipe, and a pressure protection system is provided on the output pipe between the two full containment tanks. The pressure protection system includes at least one first cut-off valve and a second pressure detector connected to the controller; in response to a trigger signal from the second pressure detector, the controller controls the opening and closing of the first cut-off valve.

2. The device according to claim 1, characterized in that, the pressure protection system includes a plurality of the second pressure detectors arranged at multiple positions on the output pipe; the controller controls the opening and closing of a plurality of the first cut-off valves in response to trigger signals sent by a preset number of the second pressure detectors.

3. The device according to claim 2, characterized in that, the device further includes a third pressure detector provided on the output pipe and a second control valve connected in series with the first cut-off valve; the third pressure detector and the second control valve are respectively connected to the controller, and the controller controls the opening degree of the second control valve according to the value of the third pressure detector.

4. The device according to claim 1, characterized in that, the valve group includes a third control valve and a second cut-off valve connected in series, and the third control valve is connected to the controller.

5. The device according to claim 1, characterized in that, a third cut-off valve is provided on the output and / or input pipeline of any one of the full containment tanks.

6. The device according to any one of claims 1 to 5, characterized in that, among two full containment tanks with different design pressures, the full containment tank with the smallest design pressure is arranged closest to the output end of the output pipe.

7. A pressure control method for the coexistence of different types of full containment tanks, characterized in that, it includes the device according to any one of claims 1 to 6; the method includes: presetting a negative pressure air supplement setting value and an overpressure setting value for two full containment tanks with different design pressures; wherein, the first overpressure setting value of the full containment tank closest to the output end of the output pipe is less than the second overpressure setting value of the other full containment tank; when all the full containment tanks are operating normally, close all the first control valves and the valve group, and open the remaining valves; when any one of the full containment tanks reaches the preset negative pressure air supplement setting value, in response to a signal triggered by the corresponding first pressure detector, control the corresponding valve group to open and perform air supplement; When the pressure of the output pipe is greater than the first overpressure set value, in response to the trigger signal of the second pressure detector, control the first cut-off valve to close; detect the pressures in the two all-welded tanks with different design pressures, and when the pressure value detected in any one of the all-welded tanks is greater than the corresponding overpressure set value, open the corresponding first control valve to discharge the gas to the flare.

8. The method according to claim 7, wherein, the step of controlling the first cut-off valve to close specifically includes: among multiple second pressure detectors, when a preset number of second pressure detectors detect that the pressure in the output pipe is greater than the first overpressure set value, control the first cut-off valve to close.

9. The method according to any one of claims 7 or 8, wherein, it includes a third pressure detector arranged on the output pipe and a second control valve connected in series with the first cut-off valve; the method further includes: presetting the pressure stability value of the output pipe; according to the pressure on the output pipe monitored by the third pressure detector in real time, adjust the opening and closing degree of the second control valve to maintain the pressure in the output pipe to reach the stability value.

10. A pressure control system for the coexistence of different types of all-welded tanks, wherein, it includes the device according to any one of claims 1 to 6; the system includes: a pressure threshold definition module for presetting the negative pressure air supplement set value and the overpressure set value of two all-welded tanks with different design pressures; wherein, the first overpressure set value of the all-welded tank closest to the output end of the output pipe is less than the second overpressure set value of the other all-welded tank; a normal operation control module for closing all the first control valves and the valve group and opening the remaining valves when all the all-welded tanks are operating normally; an air supplement control module for controlling the corresponding valve group to open and performing air supplement in response to the signal triggered by the corresponding first pressure detector when any one of the all-welded tanks reaches the preset negative pressure air supplement set value; an overpressure control module for controlling the first cut-off valve to close in response to the trigger signal of the second pressure detector when the pressure of the output pipe is greater than the first overpressure set value; detecting the pressures in the two all-welded tanks with different design pressures, and when the pressure value detected in any one of the all-welded tanks is greater than the corresponding overpressure set value, opening the corresponding first control valve to discharge the gas to the flare.

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