Liquefied natural gas (LNG) follow-up mixing device and calorific value balance control system

Abstract

The invention relates to an LNG (Liquefied Natural Gas) follow-up mixing device. The device comprises two LNG inlet pipelines, an LNG outlet pipeline, a secondary mixing cavity, a spiral turbulator and a corrugated net, one of the two LNG inlet pipelines is an active LNG inlet pipeline, and a corrugated net is arranged on a communicating passage of the active LNG inlet pipeline and the secondary mixing cavity; the other one of the two LNG inlet pipelines is a follow-up adjusting type LNG inlet pipeline, and the follow-up adjusting type LNG inlet pipeline is communicated to the secondary mixing cavity; and a spiral spoiler and a corrugated net are arranged on a communicating path of the outlet of the secondary mixing cavity and the LNG outlet pipeline. According to the multi-source LNG mixed heating value follow-up balance control method, multi-source LNG mixed heating value follow-up balance accurate control is achieved, and the requirement of stable heating value output or transportation provided by a downstream gas consumption unit is met.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG (liquid natural gas) operation control, in particular to an LNG follow-up mixing device and a heat generation balance control system. Background Art

[0002] At LNG receiving stations, LNG liquefaction plants, and LNG storage depots, the calorific value dynamic balance of LNG in liquid state is currently a blank in the industry.

[0003] In the direct gasification and export of LNG facilities and the transportation of LNG liquid in tanks, some end users who are sensitive to fluctuations in calorific value have put forward requirements for calorific value stability. The current technical solution is to achieve the goal of stable calorific value balance of LNG for export or transportation by measuring the calorific value of LNG in different LNG storage tanks, adjusting and combining the proportion of LNG flow representing different calorific values ​​pumped out from different LNG storage tanks.

[0004] However, there are still three fundamental difficulties that the current technical solutions have not yet solved:

[0005] First, there is no direct instrument to measure the calorific value of LNG in LNG storage tanks. Basically, the measurement value when the imported LNG is unloaded into the tank is used as the standard. However, multiple imported LNG unloading may have occurred during this period, and the deviation between the estimated value and the actual value may be large.

[0006] Second, when mixing LNG pumped out of different LNG storage tanks, there is a lack of precise mixing control process. Due to the ultra-low temperature characteristics of LNG medium, which is usually minus 160°C, the equipment used to sample and measure the calorific value of LNG is expensive, usually tens of millions of yuan per set. It is not realistic to install a set for calorific value measurement on each LNG pipeline, and the existing technology can only achieve intermittent sampling and calorific value measurement at intervals of 4 to 5 minutes per time, and cannot be measured online in real time. Therefore, the calorific value of the mixed LNG can only be measured and then fed back to the front end of the process to adjust and optimize the proportion of different LNG pipelines. There is a large time lag, and it is difficult to achieve stability in the control process and results;

[0007] Third, the mixing device currently available in the industry is a static mixer, with a mixing effect of about 97%. As a passive turbulent mixing device, stratification may occur in the subsequent mixing pipeline due to incomplete front-end mixing. Summary of the invention

[0008] In view of the above problems, the purpose of the present invention is to provide a more efficient and more precise LNG calorific value balance control system, including a composite feedback adjustment process of feedforward + feedback in a multi-channel LNG mixing process, adding an online real-time monitoring instrument, and adding a spiral nozzle + spiral adaptive spoiler component to the pipeline mixer structure to achieve a mixing uniformity of 99.9% and avoid subsequent stratification. The present invention is used to achieve precise control of the calorific value of multi-source LNG mixing with dynamic balance, meeting the needs of downstream gas users for stable calorific value transmission or transportation.

[0009] To achieve the above objectives, this application adopts the following technical solutions:

[0010] In a first aspect, the present application provides an LNG follow-up mixing device, characterized in that the device comprises: two LNG inlet pipelines and one LNG outlet pipeline, a secondary mixing chamber, a spiral spoiler and a corrugated net;

[0011] One of the two LNG inlet pipelines is an active LNG inlet pipeline, and a corrugated net is provided on the communication passage between the active LNG inlet pipeline and the secondary mixing chamber; the other of the two LNG inlet pipelines is a follow-up regulating LNG inlet pipeline, and the follow-up regulating LNG inlet pipeline is connected to the secondary mixing chamber;

[0012] A spiral spoiler and a corrugated net are provided in a communication path between the outlet of the secondary mixing chamber and the LNG outlet pipeline.

[0013] In one implementation of the present invention, the direction of the active LNG inlet pipeline is parallel to the axis of the LNG follow-up mixing device;

[0014] The direction of the follow-up adjustable LNG inlet pipeline is at an angle of 45 to 90 degrees to the axis of the LNG follow-up mixing device. It bends 90 degrees when entering the LNG follow-up mixing device. The outlet direction is parallel to the axis of the LNG follow-up mixing device and is opposite to the direction of the active LNG inlet pipeline. The pipe wall at the outlet end has a circumferential opening to form a spiral nozzle.

[0015] In one implementation of the present invention, the diameter of the hole groove of the spiral nozzle is 1 to 5 mm.

[0016] In one implementation of the present invention, the secondary mixing chamber is an open sphere, suspended in the air, and connected and fixed to the inner wall of the LNG follow-up mixing device by supporting ribs at the top and bottom.

[0017] In an implementation of the present invention, the spiral spoiler is composed of a spiral spoiler rotating shaft and a spiral spoiler rotating sheet.

[0018] The present invention provides an LNG follow-up heat generation balance control system, comprising at least two LNG inlet pipelines and one LNG outlet pipeline, a calorific value meter, a flow meter, a regulating valve, an LNG follow-up mixing device and a PLC control cabinet;

[0019] The at least two LNG inlet pipelines are connected to the LNG outlet pipeline through a plurality of the LNG follow-up mixing devices, and the LNG follow-up mixing devices are the aforementioned LNG follow-up mixing devices;

[0020] On each communication path between the LNG inlet pipeline and the LNG follow-up mixing device, and on the communication path between the LNG follow-up mixing device and the LNG outlet pipeline, a calorimeter for measuring heat and a flowmeter for measuring flow are provided, and the regulating valve is also provided;

[0021] The PLC control cabinet is connected to the calorific value meter and the flow meter through a signal line to obtain the heat and the flow;

[0022] The PLC control cabinet is connected to the regulating valve via a control line, and a linear weighted calculation method is used to adjust the opening of the regulating valve according to the heat and the flow.

[0023] In one implementation of the present invention, two LNG inlet pipelines are included, one of which is an active LNG inlet pipeline and the other is a follow-up regulating LNG inlet pipeline; the system accordingly includes two LNG follow-up mixing devices.

[0024] In one implementation of the present invention, the linear weighted calculation method includes:

[0025] Q1+Q2=Q3

[0026] H1×Q1+H2×Q2=H3×Q3

[0027] H1×Q1+H2×Q2=H3×Q1+H3×Q2

[0028] Q2=(H3-H1)×Q1 / (H3-H2)

[0029] Among them, Q1 is the flow rate of LNG in the active LNG inlet pipeline; Q2 is the flow rate of LNG in the follow-up regulation type LNG inlet pipeline; Q3 is the flow rate of LNG in the LNG export pipeline; H1 is the calorific value of LNG in the active LNG inlet pipeline process; H2 is the calorific value of LNG in the follow-up regulation type LNG inlet pipeline process; H3 is the calorific value of LNG in the LNG export pipeline.

[0030] The present invention adopts the above technical solution, which has the following advantages:

[0031] (1) The LNG calorific value balance control system of the present invention realizes the precise control of the calorific value of multiple LNG channels with dynamic balance, and the calorific value of the mixed LNG reaches the target setting value and is stably balanced for a long period of time;

[0032] (2) The LNG mixer structure of the present invention adds a spiral nozzle + a spiral adaptive spoiler component to the interior of the traditional pipeline mixer, achieving a mixing uniformity of 99.9%, avoiding subsequent stratification, and meeting the needs of downstream gas users for stable heat output transmission or transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of a LNG heat value balance control system according to an embodiment of the present invention;

[0034] Figure 2 Schematic diagram of an LNG follow-up mixing device in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0036] In view of the problems of the prior art, the present invention provides a LNG follow-up mixing device and a LNG calorific value balance control system.

[0037] The LNG follow-up mixing device includes: two LNG inlet pipelines and one LNG outlet pipeline, a secondary mixing chamber, a spiral spoiler and a corrugated net;

[0038] One of the two LNG inlet pipelines is an active LNG inlet pipeline, and a corrugated net is provided on the communication passage between the active LNG inlet pipeline and the secondary mixing chamber; the other of the two LNG inlet pipelines is a follow-up regulating LNG inlet pipeline, and the follow-up regulating LNG inlet pipeline is connected to the secondary mixing chamber;

[0039] A spiral spoiler and a corrugated net are provided in a communication path between the outlet of the secondary mixing chamber and the LNG outlet pipeline.

[0040] An LNG follow-up heat generation balance control system, comprising at least two LNG inlet pipelines and one LNG outlet pipeline, a calorific value meter, a flow meter, a regulating valve, an LNG follow-up mixing device and a PLC control cabinet;

[0041] The at least two LNG inlet pipelines are connected to the LNG outlet pipeline through a plurality of the LNG follow-up mixing devices, and the LNG follow-up mixing devices are the aforementioned LNG follow-up mixing devices;

[0042] On each communication path between the LNG inlet pipeline and the LNG follow-up mixing device, and on the communication path between the LNG follow-up mixing device and the LNG outlet pipeline, a calorimeter for measuring heat and a flowmeter for measuring flow are provided, and the regulating valve is also provided;

[0043] The PLC control cabinet is connected to the calorific value meter and the flow meter through a signal line to obtain the heat and the flow;

[0044] The PLC control cabinet is connected to the regulating valve via a control line, and a linear weighted calculation method is used to adjust the opening of the regulating valve according to the heat and the flow.

[0045] The above-mentioned device and system are described below in some more detailed embodiments in conjunction with more drawings of the present invention.

[0046] The present invention adopts the following steps to implement the technical solution:

[0047] like Figure 1 As shown, the LNG heat value balance control system includes an active LNG inlet pipeline process and a follow-up regulating LNG inlet pipeline process. The two processes are combined in two series-connected LNG follow-up mixing devices in the active LNG inlet pipeline process and then transported out. LNGA enters the active LNG inlet pipeline process, LNGB enters the follow-up regulating LNG inlet pipeline process, and the mixed LNGC is directly transported out. The specific process includes:

[0048] 1) The active LNG inlet pipeline process includes a calorimeter A (1), a flow meter A (3), a regulating valve A1 (5) and a regulating valve A2 (7), an LNG follow-up mixing device A (9) and an LNG follow-up mixing device B (10), a calorimeter C (11), and an LNG process pipeline (12) connecting each unit.

[0049] 2) The follow-up regulating type LNG inlet pipeline process includes a calorific value meter B (2), a flow meter B (4), a regulating valve B1 (6) with a follow-up control regulating function, and a regulating valve B2 (8).

[0050] 3) LNGA, through the active LNG inlet pipeline flow, passes through the calorific value meter A (1), flow meter A (3), and regulating valve A1 (5) in sequence, and is mixed with LNGB, which passes through the calorific value meter B (2), flow meter B (4), and regulating valve B1 (6) of the follow-up regulating LNG inlet pipeline flow in sequence, in the LNG follow-up mixing device A (9) according to the flow ratio calculated and fed back by the PLC control cabinet (13) in real time linear weighted manner. When the LNG follow-up mixing device A (9) or the regulating valve B1 (6) with the follow-up control regulating function fails to work normally, LNGB continues to be mixed with LNGA in the LNG follow-up mixing device B (10) through the regulating valve B (10) with the follow-up control regulating function.

[0051] 4) The mixed LNGC is directly exported after passing through the calorific value meter C (11).

[0052] 5) The PLC control cabinet (13) collects the measurement data of the calorific value meter A (1), the flow meter A (3), the calorific value meter B (2), the flow meter B (4) and the calorific value meter C (11) in real time through the signal line (15).

[0053] 6) After the PLC control cabinet (13) obtains the LNGB flow rate that should be supplied by the follow-up regulating type LNG inlet pipeline process through real-time linear weighted calculation, it directly controls the opening of the regulating valve B1 (6) or the regulating valve B2 (8) through the control line (15) to control the LNGB flow rate entering the LNG follow-up mixing device A (9) or the LNG follow-up mixing device B (10), thereby completing real-time feedback regulation.

[0054] 7) Among them, the flow rate of LNGA is an active flow rate, which may experience large flow fluctuations during operation, but does not participate in flow regulation; LNGC is a target set flow rate, which may also experience large flow fluctuations, but does not participate in flow regulation; LNGB is adaptively adjusted in real time with the changes of LNGA and LNGC based on the flow rate and calorific value of LNGA, the target set flow rate and target set calorific value of LNGC, and the calorific value of LNGB itself.

[0055] 8) The real-time linear weighted calculation completed by the PLC control cabinet (13) is as follows, where formula (3) is the final application formula. Conventional PLC control logic programming is performed according to formula (3) and embedded in the PLC control cabinet (13):

[0056] Q1+Q2=Q3

[0057] H1×Q1+H2×Q2=H3×Q3

[0058] H1×Q1+H2×Q2=H3×Q1+H3×Q2

[0059] Q2=(H3-H1)×Q1 / (H3-H2)

[0060] Among them, Q1 is the flow rate of the active LNG inlet pipeline process LNGA, which is controlled by a regulating valve and is stable, and the unit is cubic meter / second; Q2 is the flow rate of the follow-up regulating LNG inlet pipeline process LNGB, which is controlled by a regulating valve and has a follow-up control regulation function, and the unit is cubic meter / second; Q3 is the flow rate of the LNG outlet pipeline LNGC, which is also the target calorific value, and the unit is cubic meter / second; H1 is the calorific value of the active LNG inlet pipeline process LNGA, and the unit is kilojoule / cubic meter; H2 is the calorific value of the follow-up regulating LNG inlet pipeline process LNGB, and the unit is kilojoule / cubic meter; H3 is the calorific value of the LNG export pipeline LNGC, which is also the target setting calorific value, and the unit is kilojoule / cubic meter.

[0061] 9) The opening control of the regulating valve B1 (6) or regulating valve B2 (8) of LNGB adopts a composite feedback regulation process of feedforward + feedback for precise regulation:

[0062] The existing process only adopts a feed-back regulation process, that is, the calorific value meter C (11) after the LNG follow-up mixing device A (9) or the LNG follow-up mixing device B (10) at the end of the active LNG inlet pipeline process measures the calorific value data of the mixed LNGC in real time and feeds it back to the PLC control cabinet (13), and then the PLC control cabinet (13) completes the real-time linear weighted calculation, and the opening of the regulating valve B1 (6) or the regulating valve B2 (8) is directly controlled through the control line (15) to complete the follow-up regulation. However, since the calorific value meter C (11) must reach the trade measurement accuracy (0.5 level), conventional intermittent LNG sampling + chromatograph analyzer are used, and the interval time period is usually 4 to 5 minutes, resulting in a time lag in the follow-up regulation, making it difficult to achieve the accuracy requirements of the LNGC calorific value target setting value.

[0063] The present invention adopts a feed-back regulation process and sets a feed-forward regulation process: the data of the calorific value meter A (1) and the flow meter A (3) of the active LNG inlet pipeline LNGA process, and the data of the calorific value meter B (2) and the flow meter B (4) of the follow-up regulation type LNG inlet pipeline LNGB process are simultaneously transmitted to the PLC control cabinet (13) through the signal line (14), and the PLC control cabinet (13) completes the real-time linear weighted calculation, and directly controls the opening of the regulating valve B1 (6) or the regulating valve B2 (8) through the control line (15), completing the primary follow-up regulation, that is, the feed-back regulation process; and then, according to the calorific value data of the mixed LNGC measured in real time by the calorific value meter C (11) and fed back to the PLC control cabinet (13), the secondary follow-up regulation is performed, which is used for the secondary correction to improve the accuracy, that is, the feed-back regulation process. The feed-forward regulation process of the primary follow-up regulation and the feed-back regulation process of the secondary follow-up regulation together constitute a composite feedback regulation process of feed-forward + feed-back, which is used for precise regulation.

[0064] 10) The calorimeter A (1) and calorimeter B (2) used in the feedforward adjustment process of the primary follow-up adjustment are both special online real-time heat conduction or physical property transfer type calorimeters that are independent of LNG sampling and have a measurement accuracy of 1.0.

[0065] like Figure 2 As shown, the LNG follow-up mixing device includes an LNG pipeline A1 (1), an LNG pipeline A2 (2), an LNG pipeline B (3), an LNG pipeline C (12), an LNG follow-up mixing device housing (10), and an internal spiral nozzle (4), a secondary mixing chamber (5), supporting ribs (6) of the secondary mixing chamber, a spiral spoiler (7) composed of a spiral spoiler rotating shaft (8) and a spiral spoiler rotating sheet (9), and a traditional SV type (corrugated sheet cylinder) corrugated net (11).

[0066] in:

[0067] 1) LNGA enters the LNG follow-up mixing device through an active LNG inlet pipeline, including LNG pipeline A1 (1) and LNG pipeline A2 (1), and LNGB enters the LNG follow-up mixing device through a follow-up regulating LNG inlet pipeline, including LNG pipeline B (3), and after being mixed in the internal cavity of the LNG follow-up mixing device, the LNG and LNG are directly transported out through an outlet pipeline, LNG pipeline C (12).

[0068] 2) The internal cavity of the LNG follow-up mixing device is formed by being sealed by the outer shell (10) of the LNG follow-up mixing device.

[0069] 3) The direction in which the LNG pipeline B (3) enters the LNG follow-up mixing device is at an angle of 45 to 90 degrees to the axis of the LNG follow-up mixing device. It bends 90 degrees when entering the LNG follow-up mixing device, and the terminal outlet direction is parallel to the axis of the LNG follow-up mixing device and opposite to the direction of the LNG pipeline A1 (1).

[0070] 4) The end outlet pipe wall of the LNG pipe B (3) is circumferentially opened to form a spiral nozzle (4). The diameter of the hole groove of the spiral nozzle (4) is 1 to 5 mm and the spacing between the holes is limited to a limit that does not affect the strength of the pipe.

[0071] 5) The spiral nozzle (4) is located in the secondary mixing chamber (5) and is an open sphere, suspended in the air, connected and fixed to the inner wall of the LNG follow-up mixing device by supporting ribs (6) at the top and bottom. The opening direction of the secondary mixing chamber (5) is opposite to and opposite to the end outlet direction of the LNG pipeline A1 (1).

[0072] 6) LNGA of the active LNG inlet pipeline enters the LNG follow-up mixing device through two pipelines, namely, LNG pipeline A1 (1) and LNG pipeline A2 (2): one LNG pipeline A1 (1) is parallel to the axis of the LNG follow-up mixing device, and after entering the LNG follow-up mixing device, it is mixed with LNGB entering the LNG follow-up mixing device through LNG pipeline B (3), and LNGB is directly sprayed out from the opening of the secondary mixing chamber (5). The preliminarily mixed LNG then passes through the traditional SV type (corrugated sheet cylinder) corrugated net (11) for traditional primary mixing, and is exported through the outlet of LNG pipeline C (12);

[0073] 7) The spiral nozzles (4) at the ends of the other LNG pipeline A2 (2) and the LNG pipeline B (3) simultaneously enter the secondary mixing chamber (5) to undergo secondary mixing; the LNG after the secondary mixing is ejected through the opening of the secondary mixing chamber (5) to undergo convection mixing with the LNG flowing in from the opposite direction through the LNG pipeline A1 (1), i.e., tertiary mixing; the LNG after the tertiary mixing is then passed through a spiral spoiler (7) with a spiral adaptive spoiler function to undergo quaternary mixing; the LNG after the quaternary mixing is then passed through a conventional SV type (corrugated sheet cylinder) corrugated net (11) to undergo conventional primary mixing and is then exported through the outlet of the LNG pipeline C (12).

[0074] 8) wherein the spiral spoiler (7) is a mechanical rotating component, and its spiral spoiler rotating piece (9) can rotate freely around the spiral spoiler rotating axis (8), and the shape of the spiral spoiler rotating piece (9) is the same as the fan blade shape of the turbofan, and the spiral spoiler performs adaptive adjustment rotation according to the change of LNG flow rate and the mechanical impact on the rotating piece.

[0075] In summary, the present invention has the following beneficial effects:

[0076] The LNG calorific value dynamic balancing process of the present invention realizes the precise control of the calorific value dynamic balancing of multiple LNG channels, and the calorific value of the mixed LNG reaches the target setting value and is stably balanced for a long period of time;

[0077] The LNG mixer structure of the present invention adds a spiral nozzle + a spiral adaptive spoiler component inside the traditional pipeline mixer, achieving a mixing uniformity of 99.9%, avoiding subsequent stratification, and meeting the needs of downstream gas users for stable heat output transmission or transportation.

[0078] In the several embodiments provided by the present invention, it should be understood that the disclosed method can be implemented in other ways. For example, the embodiments described above are merely illustrative.

[0079] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (Processor) to perform some steps of the above-mentioned method of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program codes.

[0080] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A LNG follow-up mixing device, characterized in that: The device comprises: two LNG inlet pipelines and one LNG outlet pipeline, a secondary mixing chamber, a spiral spoiler and a corrugated net; One of the two LNG inlet pipelines is an active LNG inlet pipeline, and a corrugated net is provided on the communication passage between the active LNG inlet pipeline and the secondary mixing chamber; the other of the two LNG inlet pipelines is a follow-up regulating LNG inlet pipeline, and the follow-up regulating LNG inlet pipeline is connected to the secondary mixing chamber; A spiral spoiler and a corrugated net are provided in a communication path between the outlet of the secondary mixing chamber and the LNG outlet pipeline.

2. The LNG follow-up mixing device according to claim 1, characterized in that: The direction of the active LNG inlet pipeline is parallel to the axis of the LNG follow-up mixing device; The direction of the follow-up adjustable LNG inlet pipeline is at an angle of 45 to 90 degrees to the axis of the LNG follow-up mixing device. It bends 90 degrees when entering the LNG follow-up mixing device. The outlet direction is parallel to the axis of the LNG follow-up mixing device and is opposite to the direction of the active LNG inlet pipeline. The pipe wall at the outlet end has a circumferential opening to form a spiral nozzle.

3. The LNG follow-up mixing device according to claim 2, characterized in that: The diameter of the hole groove of the spiral nozzle is 1 to 5 mm.

4. The LNG follow-up mixing device according to claim 1, characterized in that: The secondary mixing chamber is an open sphere, suspended in the air, and connected and fixed to the inner wall of the LNG follow-up mixing device by supporting ribs at the top and bottom.

5. The LNG follow-up mixing device according to claim 1, characterized in that: The spiral spoiler is composed of a spiral spoiler rotating shaft and a spiral spoiler rotating sheet.

6. An LNG dynamic heat generation balance control system, characterized in that: It includes at least two LNG inlet pipelines and one LNG outlet pipeline, a calorific value meter, a flow meter, a regulating valve, an LNG follow-up mixing device and a PLC control cabinet; The at least two LNG inlet pipelines are connected to the LNG outlet pipeline through a plurality of the LNG follow-up mixing devices, and the LNG follow-up mixing devices are the LNG follow-up mixing devices according to claims 1 to 5; On each communication path between the LNG inlet pipeline and the LNG follow-up mixing device, and on the communication path between the LNG follow-up mixing device and the LNG outlet pipeline, a calorimeter for measuring heat and a flowmeter for measuring flow are provided, and the regulating valve is also provided; The PLC control cabinet is connected to the calorific value meter and the flow meter through a signal line to obtain the heat and the flow; The PLC control cabinet is connected to the regulating valve via a control line, and a linear weighted calculation method is used to adjust the opening of the regulating valve according to the heat and the flow.

7. The LNG follow-up heat generation balance control system according to claim 6 is characterized in that: The system comprises two LNG inlet pipelines, one of which is an active LNG inlet pipeline and the other is a follow-up regulating LNG inlet pipeline; the system correspondingly comprises two LNG follow-up mixing devices.

8. The LNG follow-up heat generation balance control system according to claim 7 is characterized in that: The linear weighted calculation method comprises: Q1+Q2=Q3 H1×Q1+H2×Q2=H3×Q3 H1×Q1+H2×Q2=H3×Q1+H3×Q2 Q2=(H3-H1)×Q1 / (H3-H2) Among them, Q1 is the flow rate of LNG in the active LNG inlet pipeline; Q2 is the flow rate of LNG in the follow-up regulation type LNG inlet pipeline; Q3 is the flow rate of LNG in the LNG export pipeline; H1 is the calorific value of LNG in the active LNG inlet pipeline process; H2 is the calorific value of LNG in the follow-up regulation type LNG inlet pipeline process; H3 is the calorific value of LNG in the LNG export pipeline.

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