Automatic pre-cooling adjusting device of LNG storage tank

Abstract

The utility model belongs to the technical field of LNG storage tank precooling equipment, and particularly discloses an LNG storage tank automatic precooling adjusting device which comprises a pneumatic adjusting valve, a temperature collecting module and a control module, and the pneumatic adjusting valve is arranged on a pipeline connecting a liquid nitrogen tank car and an LNG storage tank; the temperature collection module intermittently collects temperature signals in the LNG storage tank, the control module comprises a subtracter and a first comparator, the subtracter is used for obtaining the difference value of temperature signal values collected by the temperature collection module at two adjacent times, and the output end of the subtracter is connected with the digital-to-analog conversion module; the output end of the digital-to-analog conversion module is connected with the first input end of a first comparator, the second input end of the first comparator is connected with a temperature threshold memory, and the output end of the first comparator is connected with the opening control end of the pneumatic control valve. By adopting the technical scheme, the temperature acquisition module and the control module are utilized to realize automatic opening control of the pneumatic control valve.

Description

Technical Field

[0001] The utility model belongs to the technical field of LNG storage tank precooling equipment and relates to an automatic precooling regulating device for an LNG storage tank. Background Art

[0002] At present, the pre-cooling operation of LNG (Liquefied Natural Gas) bimetallic full containment tanks is carried out in which an operator is responsible for monitoring the temperature of various parts of the tank in the DCS (distributed control system) in the central control room, and manually calculating the temperature drop of the temperature detection points of various parts of the tank within 10 minutes, and then feeding back the temperature drop results to the on-site operators. The on-site operators manually switch the opening of the on-site pre-cooling manual regulating valve to adjust the pre-cooling flow rate according to the feedback results to achieve pre-cooling temperature drop control (pre-cooling requirements: temperature drop ≤ 5℃ / h, temperature difference between adjacent temperature detection points ≯30℃).

[0003] The existing precooling operation requires many operators, and the precooling operation is relatively frequent. The long-term continuous precooling operation (about 60 hours) has a high labor intensity for the operators. In addition, the precooling valve opening control depends entirely on the operator's experience. Different operators have different operating techniques and habits, which can easily cause the precooling temperature to drop quickly or slowly. Precooling is too dependent on manual operation, and the fatigue and negligence of the personnel can easily cause the temperature drop to exceed the standard. In severe cases, it can cause the tank weld to crack, leading to quality accidents.

[0004] For example, patent CN201510041519.9 discloses a liquefied natural gas gasification system, in which the LNG supply gasification system includes an LNG pump, an LNG gasifier and an auxiliary LNG storage tank. The auxiliary LNG storage tank is connected to the LNG gasifier via a manual regulating valve, an LNG pump, a third liquid flow sensor and a third liquid ratio regulating valve in sequence. The system uses a manual regulating valve, which consumes manpower and is inconvenient to operate. Utility Model Content

[0005] The utility model aims to provide an automatic precooling regulating device for an LNG storage tank, so as to realize automatic opening control of a pneumatic regulating valve and reduce manpower consumption.

[0006] In order to achieve the above-mentioned purpose, the basic scheme of the utility model is: an automatic pre-cooling regulating device for LNG storage tanks, comprising a pneumatic regulating valve, a temperature acquisition module and a control module, wherein the pneumatic regulating valve is arranged on a pipeline connecting a liquid nitrogen tank truck and an LNG storage tank;

[0007] The temperature acquisition module is arranged in the LNG storage tank, the output end of the temperature acquisition module is connected to the input end of the control module, and the acquisition end of the temperature acquisition module is provided with a timer for controlling the temperature acquisition module to intermittently acquire temperature signals; the control module includes a subtractor and a first comparator, the output end of the temperature acquisition module is connected to the input end of the analog-to-digital conversion module, one path of the output end of the analog-to-digital conversion module is connected to the subtrahend input end of the subtractor, the other path of the output end of the analog-to-digital conversion module is connected to the input end of the first register, the output end of the first register is connected to the minuend input end of the subtractor, and the enable end of the first register is connected to the timing signal start end of the timer;

[0008] The subtractor is used to obtain the difference between the temperature signal values ​​collected by the temperature acquisition module at two adjacent times. The output end of the subtractor is connected to the digital-to-analog conversion module, the output end of the digital-to-analog conversion module is connected to the first input end of the first comparator, the second input end of the first comparator is connected to the temperature difference threshold memory, and the output end of the first comparator is connected to the opening control end of the pneumatic control valve.

[0009] The working principle and beneficial effects of this basic solution are as follows: This technical solution installs the start regulating valve on the pipeline, and controls the pipeline conduction or closure by controlling the pneumatic regulating valve. Through the timer, the temperature acquisition module is controlled to intermittently collect the temperature information in the LNG storage tank and transmit it to the control module.

[0010] The control module obtains the difference between the temperature signal values ​​collected by the temperature acquisition module at two consecutive times through a subtractor and a register, and then inputs the difference into the first comparator, and uses the first comparator to compare the difference with the preset temperature difference threshold, and controls the opening of the pneumatic control valve based on the comparison result. In this way, the automatic control of the pneumatic control valve is realized without manual operation, reducing manpower consumption.

[0011] Further, the temperature acquisition module includes one temperature sensor or multiple temperature sensors;

[0012] When there is only one temperature sensor, the temperature sensor is placed in the middle of the LNG storage tank;

[0013] When there are multiple temperature sensors, including a first temperature sensor, a second temperature sensor and a third temperature sensor, the first temperature sensor is set at the inner tank bottom of the LNG storage tank, the second temperature sensor is installed on the inner wall of the LNG storage tank, and the third temperature sensor is placed in the middle position of the LNG storage tank.

[0014] As needed, set the required temperature sensors to collect temperature signals in the LNG storage tank to improve the accuracy of collected data.

[0015] Further, the control module also includes a second comparator, a third comparator, a second register and a third register;

[0016] The first input end of the second comparator is connected to the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the first temperature sensor, and the second input end of the second comparator is connected to the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the second temperature sensor;

[0017] The output ends of the digital-to-analog conversion module connected to the subtractor corresponding to the first temperature sensor and the digital-to-analog conversion module connected to the subtractor corresponding to the second temperature sensor are both connected to the input end of the second register, a first normally open switch is provided between the digital-to-analog conversion module connected to the subtractor corresponding to the first temperature sensor and the second register, and a second normally open switch is provided between the digital-to-analog conversion module connected to the subtractor corresponding to the second temperature sensor and the second register;

[0018] The output end of the second comparator is connected to the control end of the first switch, the output end of the second comparator is connected to the second normally open switch after a NOT gate, the output end of the second register is connected to the first input end of the third comparator after digital-to-analog conversion, and the second input end of the third comparator is connected to the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the third temperature sensor;

[0019] The output end of the second register is connected to the third register through a third normally-open switch, the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the third temperature sensor is connected to the third register through a fourth normally-open switch, the output end of the third comparator is connected to the control end of the third normally-open switch, and the output end of the third comparator is connected to the control end of the fourth normally-open switch after a NOT gate;

[0020] The output end of the third register is connected to the first input end of the first comparator after passing through the digital-to-analog conversion unit.

[0021] The second comparator is used to compare the temperature difference value collected by the first temperature sensor at two adjacent times with the temperature difference value collected by the second temperature sensor at two adjacent times. If the temperature difference value collected by the first temperature sensor at two adjacent times is greater than the temperature difference value collected by the second temperature sensor at two adjacent times, the second comparator outputs a control signal to the first normally open switch to control the first normally open switch to close, and the temperature difference value collected by the first temperature sensor at two adjacent times is input into the second register; otherwise, the second normally open switch is controlled to close, and the temperature difference value collected by the second temperature sensor at two adjacent times is input into the second register.

[0022] The second register then inputs the received difference into the third comparator, and the third comparator compares the difference in the second register with the temperature difference collected by the third temperature sensor at two adjacent times. If the difference in the second register is greater than the temperature difference collected by the third temperature sensor at two adjacent times, the third comparator outputs a control signal to the third normally open switch, controls the third normally open switch to close, and the difference in the second register is input into the third register; otherwise, controls the fourth normally open switch to close, and the temperature difference collected by the third temperature sensor at two adjacent times is input into the third register.

[0023] Finally, the third register inputs the maximum temperature difference it receives into the first comparator and compares it with the temperature difference threshold for subsequent precooling control. The data is more accurate and reliable, ensuring smooth precooling of the tank.

[0024] Furthermore, it also includes an alarm module, which includes a first alarm comparator and an alarm;

[0025] The first input end of the first alarm comparator is connected to the output end of the digital-to-analog conversion module corresponding to the subtractor, the second input end of the first alarm comparator is connected to the first alarm threshold memory, the output end of the first alarm comparator is connected to the control end of the alarm, and the alarm is installed in the working room.

[0026] The first alarm comparator compares the temperature difference value collected by the temperature sensor at two consecutive times with the first alarm threshold. If the temperature difference value collected by the temperature sensor at two consecutive times is greater than the alarm threshold, the first alarm comparator outputs a control signal to the alarm, activates the alarm, and sends out an alarm signal so that the staff can check the situation in time.

[0027] Furthermore, the alarm module also includes a second alarm comparator, a first input end of the second alarm comparator is connected to the output end of the digital-to-analog conversion module corresponding to the subtractor, a second input end of the second alarm comparator is connected to a second alarm threshold memory, and an output end of the second alarm comparator is connected to the closing control end of the pneumatic control valve.

[0028] The second alarm comparator compares the temperature difference collected by the temperature sensor at two consecutive times with the second alarm threshold. If the temperature difference collected by the temperature sensor at two consecutive times is greater than the second alarm threshold, the second alarm comparator outputs a control signal to the closing control end of the pneumatic control valve, and the pneumatic control valve is urgently closed to stop precooling and ensure the safety of the equipment.

[0029] Further, the pipeline includes a tank liquid inlet main pipe, a tank lower liquid inlet pipeline, a tank upper liquid inlet pipeline and a precooling pipeline;

[0030] The branch precooling liquid inlet interface of the tank liquid inlet main pipe is connected to the liquid nitrogen tank truck, and one end of the tank lower liquid inlet pipeline, the tank upper liquid inlet pipeline and the precooling pipeline are all connected to the tank liquid inlet main pipe, and the other end of the tank lower liquid inlet pipeline, the tank upper liquid inlet pipeline and the precooling pipeline are connected to the LNG storage tank;

[0031] The pneumatic regulating valve is arranged on the branch precooling liquid inlet interface pipeline of the storage tank liquid inlet main pipe.

[0032] Various pipelines are set up to ensure normal operation of tank precooling and storage.

[0033] Further, it also includes a first pneumatic shut-off valve, a second pneumatic shut-off valve, a third pneumatic shut-off valve, a manual shut-off valve and a manual regulating valve;

[0034] The first pneumatic shut-off valve is installed on the lower liquid inlet pipeline of the storage tank, the second pneumatic shut-off valve is arranged on the upper liquid inlet pipeline of the storage tank, and the third pneumatic shut-off valve is connected to the end of the storage tank liquid inlet main pipe away from the liquid nitrogen tank truck. When the storage tank is precooled, the first pneumatic shut-off valve, the second pneumatic shut-off valve and the third pneumatic shut-off valve are in a closed state;

[0035] The manual stop valve is located on the precooling pipeline, and the manual stop valve is in an open state;

[0036] The manual regulating valve is installed on the branch precooling interface pipeline bypass of the tank liquid inlet main pipe and is connected in parallel with the pneumatic regulating valve. When the tank is automatically precooled, the manual regulating valve is in a closed state.

[0037] The corresponding valves are set on the corresponding pipelines to facilitate the control of equipment precooling and liquid inlet. The manual regulating valve in parallel is used as a temporary precooling standby in an emergency in case the pneumatic regulating valve is damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of the automatic precooling regulating device for LNG storage tanks of the utility model;

[0039] Figure 2 It is a schematic diagram of the process of the automatic precooling regulating device of the utility model LNG storage tank.

[0040] The figure marks in the drawings of the specification include: LNG storage tank 1, first temperature sensor 2, second temperature sensor 3, third temperature sensor 4, storage tank liquid inlet main pipe 5, storage tank lower liquid inlet pipeline 6, storage tank upper liquid inlet pipeline 7, pre-cooling pipeline 8, first pneumatic shut-off valve 9, second pneumatic shut-off valve 10, third pneumatic shut-off valve 11, manual shut-off valve 12, manual regulating valve 13, pneumatic regulating valve 14, liquid nitrogen tank truck 15. DETAILED DESCRIPTION

[0041] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0042] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0043] In the description of the present utility model, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0044] The utility model discloses an automatic precooling regulating device for LNG storage tanks, such as Figure 1 and Figure 2 As shown, it includes a pneumatic regulating valve 14 (such as YSIQ20D-25B, etc.), a temperature acquisition module and a control module. The pneumatic regulating valve 14 is arranged on the pipeline connecting the liquid nitrogen tank truck 15 and the LNG storage tank 1.

[0045] The temperature acquisition module is arranged in the LNG storage tank 1, the output end of the temperature acquisition module is electrically connected to the input end of the control module, and the acquisition end of the temperature acquisition module is provided with a timer for controlling the temperature acquisition module to intermittently (such as every 10 minutes) collect temperature signals.

[0046] The control module includes a subtractor and a first comparator, the output end of the temperature acquisition module is electrically connected to the input end of the analog-to-digital conversion module, one path of the output end of the analog-to-digital conversion module is electrically connected to the subtrahend input end of the subtractor, the other path of the output end of the analog-to-digital conversion module is electrically connected to the input end of the first register, the output end of the first register is electrically connected to the minuend input end of the subtractor, and the enable end of the first register is electrically connected to the timing signal start end of the timer.

[0047] The subtractor is used to obtain the difference between the temperature signal values ​​collected by the temperature acquisition module at two adjacent times. The output end of the subtractor is connected to the digital-to-analog conversion module, the output end of the digital-to-analog conversion module is electrically connected to the first input end of the first comparator, the second input end of the first comparator is electrically connected to the temperature difference threshold memory, and the output end of the first comparator is electrically connected to the opening control end of the pneumatic control valve 14.

[0048] In the utility model, the subtractor can adopt CD40110 subtractor, etc., the comparator is preferably but not limited to LM324, LM339, the temperature sensor can choose PT100, etc., the memory can be 24CXX series, 93CXX series, etc., the registers can be EAX, EBX, etc., the timer can be HSK-T40, TC420, KEDSUM, etc., and the analog-to-digital conversion unit can be AD9634BCPZ-170 analog-to-digital converter, etc.

[0049] When in use, the start regulating valve is installed on the pipeline, and the pipeline conduction or closing control is realized by controlling the pneumatic regulating valve 14. The temperature acquisition module is controlled to intermittently collect the temperature information in the LNG storage tank 1 through the timer, and transmit it to the control module.

[0050] The control module obtains the difference between the temperature signal values ​​collected by the temperature acquisition module at two adjacent times through a subtractor and a register, and then inputs the difference into the first comparator, and uses the first comparator to compare the difference with the preset temperature difference threshold value. Based on the comparison result, the opening of the pneumatic control valve 14 is controlled, that is, if the comparison difference of the first comparator is less than the preset temperature difference threshold value, the opening of the pneumatic control valve 14 is increased, otherwise, the opening of the pneumatic control valve 14 is reduced. In this way, the automatic control of the pneumatic control valve 14 is achieved without manual operation, reducing manpower consumption.

[0051] In a preferred solution of the present invention, the temperature acquisition module includes one temperature sensor or multiple temperature sensors.

[0052] When there is only one temperature sensor, the temperature sensor is placed in the middle of the LNG storage tank 1;

[0053] When there are multiple temperature sensors, including a first temperature sensor 2 (5 can be set), a second temperature sensor 3 (10 can be set) and a third temperature sensor 4 (2 can be set), the first temperature sensor 2 is fixedly set (such as bonding, welding, inlaying, etc.) on the inner tank bottom of the LNG storage tank 1, the second temperature sensor 3 is fixedly installed (such as bonding, inlaying, etc.) on the inner wall of the LNG storage tank 1, and they are arranged at equal distances according to the height of the tank wall. The third temperature sensor 4 is placed in the middle of the LNG storage tank 1, such as suspending the third temperature sensor 4 in the center of the LNG storage tank 1 through a bracket structure, and is located under the suspended top of the LNG storage tank 1.

[0054] As required, the required temperature sensors are set to collect the temperature signal in the LNG storage tank 1 to improve the accuracy of the collected data.

[0055] In a preferred solution of the present invention, if multiple temperature sensors are used, the control module further includes a second comparator, a third comparator, a second register and a third register.

[0056] The first input end of the second comparator is electrically connected to the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the first temperature sensor 2 , and the second input end of the second comparator is electrically connected to the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the second temperature sensor 3 .

[0057] The output ends of the digital-to-analog conversion module connected to the subtractor corresponding to the first temperature sensor 2 and the digital-to-analog conversion module connected to the subtractor corresponding to the second temperature sensor 3 are both electrically connected to the input end of the second register, a first normally open switch is provided between the digital-to-analog conversion module connected to the subtractor corresponding to the first temperature sensor 2 and the second register, and a second normally open switch is provided between the digital-to-analog conversion module connected to the subtractor corresponding to the second temperature sensor 3 and the second register.

[0058] The output end of the second comparator is electrically connected to the control end of the first switch, the output end of the second comparator is electrically connected to the second normally open switch after passing through the NOT gate, the output end of the second register is electrically connected to the first input end of the third comparator after digital-to-analog conversion, and the second input end of the third comparator is electrically connected to the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the third temperature sensor 4.

[0059] The output end of the second register is electrically connected to the third register through the third normally-open switch, the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the third temperature sensor 4 is electrically connected to the third register through the fourth normally-open switch, the output end of the third comparator is electrically connected to the control end of the third normally-open switch, and the output end of the third comparator is electrically connected to the control end of the fourth normally-open switch after passing through the NOT gate.

[0060] The output end of the third register is electrically connected to the first input end of the first comparator after passing through the digital-to-analog conversion unit.

[0061] The second comparator is used to compare the temperature difference value collected by the first temperature sensor 2 at two adjacent times with the temperature difference value collected by the second temperature sensor 3 at two adjacent times. If the temperature difference value collected by the first temperature sensor 2 at two adjacent times is greater than the temperature difference value collected by the second temperature sensor 3 at two adjacent times, the second comparator outputs a control signal to the first normally open switch to control the first normally open switch to close, and the temperature difference value collected by the first temperature sensor 2 at two adjacent times is input into the second register; otherwise, the second normally open switch is controlled to close, and the temperature difference value collected by the second temperature sensor 3 at two adjacent times is input into the second register.

[0062] The second register then inputs the received difference into the third comparator, and the third comparator compares the difference in the second register with the temperature difference collected by the third temperature sensor 4 at two adjacent times. If the difference in the second register is greater than the temperature difference collected by the third temperature sensor 4 at two adjacent times, the third comparator outputs a control signal to the third normally open switch, controls the third normally open switch to close, and the difference in the second register is input into the third register; otherwise, controls the fourth normally open switch to close, and the temperature difference collected by the third temperature sensor 4 at two adjacent times is input into the third register.

[0063] Finally, the third register inputs the maximum temperature difference it receives into the first comparator and compares it with the temperature difference threshold for subsequent precooling control. The data is more accurate and reliable, ensuring smooth precooling of the storage tank 1.

[0064] In a preferred embodiment of the utility model, the automatic precooling adjustment device of the LNG storage tank 1 further includes an alarm module, which includes a first alarm comparator and an alarm, and the alarm can be a buzzer, an LED lamp, etc. The first input end of the first alarm comparator is electrically connected to the output end of the digital-to-analog conversion module corresponding to the subtractor, the second input end of the first alarm comparator is electrically connected to the first alarm threshold memory, the output end of the first alarm comparator is electrically connected to the control end of the alarm, and the alarm is installed in the working room.

[0065] The first alarm comparator compares the temperature difference value collected by the temperature sensor at two consecutive times with the first alarm threshold. If the temperature difference value collected by the temperature sensor at two consecutive times is greater than the alarm threshold (such as 20°C), the first alarm comparator outputs a control signal to the alarm, activates the alarm, and sends out an alarm signal so that the staff can check the situation in time.

[0066] More preferably, the alarm module also includes a second alarm comparator, a first input end of the second alarm comparator is electrically connected to the output end of the digital-to-analog conversion module corresponding to the subtractor, a second input end of the second alarm comparator is electrically connected to a second alarm threshold memory, and an output end of the second alarm comparator is electrically connected to the closing control end of the pneumatic regulating valve 14.

[0067] The second alarm comparator compares the temperature difference collected by the temperature sensor at two consecutive times with the second alarm threshold (such as 29°C). If the temperature difference collected by the temperature sensor at two consecutive times is greater than the second alarm threshold, the second alarm comparator outputs a control signal to the closing control end of the pneumatic control valve 14, and the pneumatic control valve 14 is urgently closed to stop precooling and ensure the safety of the equipment.

[0068] In a preferred embodiment of the utility model, the pipeline includes a tank liquid inlet main pipe 5, a tank lower liquid inlet pipe 6, a tank upper liquid inlet pipe 7 and a precooling pipe 8. One end of the tank liquid inlet main pipe 5 is connected to the liquid nitrogen tank truck 15, one end of the tank lower liquid inlet pipe 6, the tank upper liquid inlet pipe 7 and the precooling pipe 8 are all connected to the tank liquid inlet main pipe 5, and the other end of the tank lower liquid inlet pipe 6, the tank upper liquid inlet pipe 7 and the precooling pipe 8 are connected to the LNG storage tank 1. The pneumatic regulating valve 14 is arranged on the branch precooling liquid inlet interface pipeline of the tank liquid inlet main pipe 5, and a variety of pipelines are arranged to ensure the normal operation of precooling and storage of the storage tank 1.

[0069] In a preferred embodiment of the utility model, the automatic precooling regulating device of the LNG storage tank 1 also includes a first pneumatic shut-off valve 9, a second pneumatic shut-off valve 10, a third pneumatic shut-off valve 11 (the pneumatic shut-off valve can adopt a pneumatic piston type ultra-low temperature pressure balanced single-seat shut-off valve, model YSIS26D-25K, etc.), a manual shut-off valve 12 (such as DJ61F-25P, etc.) and a manual regulating valve 13 (the manual shut-off valve or regulating valve can adopt a low-temperature long-axis shut-off valve, model DJ61F-25P, etc.).

[0070] The first pneumatic shut-off valve 9 is installed on the lower liquid inlet pipeline 6 of the storage tank, the second pneumatic shut-off valve 10 is arranged on the upper liquid inlet pipeline 7 of the storage tank, and the third pneumatic shut-off valve 11 is connected to the end of the storage tank liquid inlet main pipe 5 away from the liquid nitrogen tank truck 15. When the storage tank is precooled, the first pneumatic shut-off valve 9, the second pneumatic shut-off valve 10 and the third pneumatic shut-off valve 11 are in a closed state.

[0071] The manual stop valve 12 is located on the precooling pipeline 8, and the manual stop valve 12 is in an open state. The manual regulating valve 13 is installed on the branch precooling interface pipeline bypass of the tank inlet main pipe 5, and is connected in parallel with the pneumatic regulating valve 14. When the tank is automatically precooled, the manual regulating valve 13 is in a closed state.

[0072] The corresponding valves are set on the corresponding pipelines to facilitate the control of equipment precooling and liquid inlet.

[0073] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0074] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An automatic precooling adjustment device for LNG storage tanks, characterized in that: It includes a pneumatic regulating valve, a temperature acquisition module and a control module, wherein the pneumatic regulating valve is arranged on a pipeline connecting a liquid nitrogen tank truck and an LNG storage tank; The temperature acquisition module is arranged in the LNG storage tank, the output end of the temperature acquisition module is connected to the input end of the control module, and the acquisition end of the temperature acquisition module is provided with a timer for controlling the temperature acquisition module to intermittently acquire temperature signals; the control module includes a subtractor and a first comparator, the output end of the temperature acquisition module is connected to the input end of the analog-to-digital conversion module, one path of the output end of the analog-to-digital conversion module is connected to the subtrahend input end of the subtractor, the other path of the output end of the analog-to-digital conversion module is connected to the input end of the first register, the output end of the first register is connected to the minuend input end of the subtractor, and the enable end of the first register is connected to the timing signal start end of the timer; The subtractor is used to obtain the difference between the temperature signal values ​​collected by the temperature acquisition module at two adjacent times. The output end of the subtractor is connected to the digital-to-analog conversion module, the output end of the digital-to-analog conversion module is connected to the first input end of the first comparator, the second input end of the first comparator is connected to the temperature difference threshold memory, and the output end of the first comparator is connected to the opening control end of the pneumatic control valve.

2. The automatic precooling regulating device for LNG storage tanks according to claim 1, characterized in that: The temperature acquisition module includes one temperature sensor or multiple temperature sensors; When there is only one temperature sensor, the temperature sensor is placed in the middle of the LNG storage tank; When there are multiple temperature sensors, including a first temperature sensor, a second temperature sensor and a third temperature sensor, the first temperature sensor is set at the inner tank bottom of the LNG storage tank, the second temperature sensor is installed on the inner wall of the LNG storage tank, and the third temperature sensor is placed in the middle position of the LNG storage tank.

3. The automatic precooling regulating device for LNG storage tanks according to claim 2, characterized in that: The control module also includes a second comparator, a third comparator, a second register and a third register; The first input end of the second comparator is connected to the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the first temperature sensor, and the second input end of the second comparator is connected to the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the second temperature sensor; The output ends of the digital-to-analog conversion module connected to the subtractor corresponding to the first temperature sensor and the digital-to-analog conversion module connected to the subtractor corresponding to the second temperature sensor are both connected to the input end of the second register, a first normally open switch is provided between the digital-to-analog conversion module connected to the subtractor corresponding to the first temperature sensor and the second register, and a second normally open switch is provided between the digital-to-analog conversion module connected to the subtractor corresponding to the second temperature sensor and the second register; The output end of the second comparator is connected to the control end of the first switch, the output end of the second comparator is connected to the second normally open switch after a NOT gate, the output end of the second register is connected to the first input end of the third comparator after digital-to-analog conversion, and the second input end of the third comparator is connected to the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the third temperature sensor; The output end of the second register is connected to the third register through a third normally-open switch, the output end of the digital-to-analog conversion module connected to the subtractor corresponding to the third temperature sensor is connected to the third register through a fourth normally-open switch, the output end of the third comparator is connected to the control end of the third normally-open switch, and the output end of the third comparator is connected to the control end of the fourth normally-open switch after a NOT gate; The output end of the third register is connected to the first input end of the first comparator after passing through the digital-to-analog conversion unit.

4. The automatic precooling regulating device for LNG storage tanks according to claim 1, characterized in that: Also included is an alarm module, the alarm module including a first alarm comparator and an alarm; The first input end of the first alarm comparator is connected to the output end of the digital-to-analog conversion module corresponding to the subtractor, the second input end of the first alarm comparator is connected to the first alarm threshold memory, the output end of the first alarm comparator is connected to the control end of the alarm, and the alarm is installed in the working room.

5. The automatic precooling regulating device for LNG storage tanks according to claim 4, characterized in that: The alarm module also includes a second alarm comparator, a first input end of the second alarm comparator is connected to the output end of the digital-to-analog conversion module corresponding to the subtractor, a second input end of the second alarm comparator is connected to a second alarm threshold memory, and an output end of the second alarm comparator is connected to the closing control end of the pneumatic control valve.

6. The automatic precooling regulating device for LNG storage tanks according to claim 1, characterized in that: The pipeline includes a tank liquid inlet main pipe, a tank lower liquid inlet pipeline, a tank upper liquid inlet pipeline and a precooling pipeline; The branch precooling liquid inlet interface of the tank liquid inlet main pipe is connected to the liquid nitrogen tank truck, and one end of the tank lower liquid inlet pipeline, the tank upper liquid inlet pipeline and the precooling pipeline are all connected to the tank liquid inlet main pipe, and the other end of the tank lower liquid inlet pipeline, the tank upper liquid inlet pipeline and the precooling pipeline are connected to the LNG storage tank; The pneumatic regulating valve is arranged on the branch precooling liquid inlet interface pipeline of the storage tank liquid inlet main pipe.

7. The automatic precooling regulating device for LNG storage tanks according to claim 6, characterized in that: It also includes a first pneumatic shut-off valve, a second pneumatic shut-off valve, a third pneumatic shut-off valve, a manual shut-off valve and a manual regulating valve; The first pneumatic shut-off valve is installed on the lower liquid inlet pipeline of the storage tank, the second pneumatic shut-off valve is arranged on the upper liquid inlet pipeline of the storage tank, and the third pneumatic shut-off valve is connected to the end of the storage tank liquid inlet main pipe away from the liquid nitrogen tank truck. When the storage tank is precooled, the first pneumatic shut-off valve, the second pneumatic shut-off valve and the third pneumatic shut-off valve are in a closed state; The manual stop valve is located on the precooling pipeline, and the manual stop valve is in an open state; The manual regulating valve is installed on the branch precooling interface pipeline bypass of the tank liquid inlet main pipe and is connected in parallel with the pneumatic regulating valve. When the tank is automatically precooled, the manual regulating valve is in a closed state.

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