LNG temperature adjusting device and method without phase change

Abstract

The application provides an LNG temperature adjusting device and method without phase change, wherein the temperature adjusting device comprises an LNG storage device, an LNG filling device and an LNG gas dispenser; the LNG storage device is connected with the LNG filling device and the LNG gas dispenser respectively, and is used for storing LNG solution; the LNG filling device comprises an LNG submersible pump and an air temperature heater, and is used for adjusting the temperature of the LNG solution; and the LNG gas dispenser is used for gas filling operation of the LNG solution. The application can pre-cool the connecting pipeline and components from the LNG submersible pump to the LNG gas dispenser before filling, so as to avoid rapid gasification of LNG caused by hot pipeline and components in the initial filling stage. After the LNG submersible pump is started, the outlet pressure of the LNG submersible pump is adjusted, so that the pressure is higher than the saturation pressure corresponding to the liquid temperature and is maintained stable, so that only temperature rise but no gasification is generated in the conveying process, and the gasification in the conveying process is inhibited.

Description

TECHNICAL FIELD

[0001] The present application relates to the LNG filling device temperature adjusting technical field, and particularly relates to an LNG temperature adjusting device and a temperature adjusting method without phase change. BACKGROUND

[0002] With the rise of oil prices, more and more LNG vehicles are put into the market, and the LNG vehicles are filled by LNG filling devices. The LNG filling device pressurizes the LNG in the LNG storage tank, and fills the LNG to the LNG fuel vehicle after metering by the LNG dispenser. The LNG storage tank of the LNG filling station stores LNG at a low temperature, and the temperature of the LNG after the pump can reach about -155 DEG C. In order to ensure the continuous and stable operation of the engine and meet the use demand of the LNG vehicle, the filled LNG needs to be adjusted to the saturated pressure, so that the pressure in the vehicle-mounted LNG bottle of the vehicle is maintained, and the LNG temperature is not lower than -140 DEG C.

[0003] At present, the heating of the LNG usually adopts an air temperature type heater, and the conventional heater adopts a finned tube, and the heating efficiency is high. During the heating process, part of the LNG will change from the liquid state to the gaseous state, that is, phase change occurs. The LNG pumped out by the LNG pump will absorb heat along the way through the gasifier and the pipeline. Once the pressure of the LNG at the pump outlet is lower than the saturated pressure of the LNG at the temperature, the heat absorption of the LNG will cause gasification, that is, phase change occurs. Once the LNG heated by the air temperature type heater produces gas, it is difficult to remove the gas by process means in the rear pipeline. The LNG dispenser adopts a mass flow meter for metering. When the gaseous content in the medium exceeds the standard, the metering accuracy will be affected, and the dispenser will not start filling. SUMMARY

[0004] Therefore, it is necessary to provide an LNG temperature adjusting device and a temperature adjusting method without phase change in view of the above technical problems.

[0005] An LNG temperature adjusting device without phase change comprises an LNG liquid storage device, an LNG filling device and an LNG dispenser.

[0006] The LNG liquid storage device is connected with the LNG filling device and the LNG dispenser respectively, and is used for storing LNG solution. The LNG filling device comprises an LNG pump and an air temperature heater, and is used for adjusting the temperature of the LNG solution. The LNG dispenser is used for gas filling operation of the LNG solution.

[0007] The LNG storage device comprises an LNG storage tank, a root valve, and a first connecting pipeline. The first connecting pipeline has four groups of pipelines, namely a liquid-phase pipeline, a gas-phase pipeline, an upper liquid inlet pipeline, and a lower liquid inlet pipeline. Each group of the first connecting pipeline is provided with a root valve. One end of the liquid-phase pipeline and the gas-phase pipeline is connected with the LNG storage tank, and the other end is connected with the LNG filling device. One end of the upper liquid inlet pipeline and the lower liquid inlet pipeline is connected with the LNG storage tank, and the other end is connected with the LNG dispenser after being gathered.

[0008] The LNG filling device further comprises a vacuum pump pool, a pressure transmitter, a first temperature transmitter, a second temperature transmitter, a first pneumatic stop valve, a second pneumatic stop valve, a third pneumatic stop valve, and a second connecting pipeline. The second connecting pipeline comprises a liquid filling pipeline, an inlet gathering pipeline, and an outlet gathering pipeline.

[0009] The LNG submersible pump is installed in the vacuum pump pool. The vacuum pump pool has three groups of interfaces, namely a liquid inlet, a gas return, and a pump outlet. The other end of the liquid inlet is connected with the liquid-phase pipeline of the LNG storage device. The other end of the gas return is connected with the gas-phase pipeline of the LNG storage device.

[0010] The filling device is provided with three groups of liquid filling pipelines. One group is a bypass pipeline, which is provided with a first pneumatic stop valve. The other two groups are heating pipelines, which are provided with a second pneumatic stop valve and a third pneumatic stop valve. The three groups of liquid filling pipelines are gathered in the inlet gathering pipeline. The inlet gathering pipeline is connected with the pump outlet of the vacuum pump pool. The other end of the heating pipeline is connected with the air temperature heater. The pressure transmitter and the first temperature transmitter are arranged on the inlet gathering pipeline. The three groups of liquid filling pipelines are gathered in the outlet gathering pipeline. The outlet gathering pipeline is connected with the LNG dispenser. The second temperature transmitter is arranged on the outlet gathering pipeline.

[0011] The LNG filling device is provided with a group of gas filling circulation pipelines. One end of the gas filling circulation pipeline is connected with the upper liquid inlet pipeline and the lower liquid inlet pipeline. The other end is connected with the LNG dispenser.

[0012] In one embodiment, the LNG dispenser comprises a liquid inlet and a gas return.

[0013] The liquid inlet is connected with the outlet gathering pipeline of the LNG filling device. The gas return is connected with the gas filling circulation pipeline of the LNG filling device.

[0014] The LNG temperature adjusting method without phase change comprises the following steps: starting the LNG submersible pump for pre-cooling operation; stopping the pre-cooling operation in response to the first temperature of the first temperature transmitter being greater than or equal to a preset first temperature threshold and the second temperature of the second temperature transmitter being greater than or equal to a preset second temperature threshold;

[0015] starting the liquid feeding mode of the LNG submersible pump; calculating a temperature difference value in response to the third temperature of the first temperature transmitter being greater than or equal to a preset third temperature threshold and less than a preset fourth temperature threshold; starting single-path heating and opening the second pneumatic stop valve or the third pneumatic stop valve in response to the temperature difference value being less than or equal to a preset fifth temperature threshold; starting double-path heating and opening the second pneumatic stop valve and the third pneumatic stop valve in response to the temperature difference value being greater than the preset fifth temperature threshold; opening the bypass and opening the first pneumatic stop valve in response to the third temperature of the first temperature transmitter being greater than or equal to the preset fourth temperature threshold; switching the single-path heating to the double-path heating in response to the fourth temperature of the second temperature transmitter being less than a preset sixth temperature threshold; starting the LNG liquid tank temperature adjusting state in response to the heating mode being the double-path heating.

[0016] calculating a preset first pressure; adjusting the pressure of the pressure transmitter by the LNG submersible pump in response to the pressure of the pressure transmitter being less than the preset first pressure; and performing liquid feeding operation in response to the pressure of the pressure transmitter being greater than or equal to the preset first pressure.

[0017] In one embodiment, the temperature difference value is calculated by the following formula:

[0018] ΔT=T1 ′ -T3

[0019] wherein ΔT represents the temperature difference value, T1 ′ represents the preset fourth temperature threshold, and T3 represents the third temperature. In one embodiment, the preset first pressure is calculated by the following formula:

[0020] P ′ =(P1+ΔP)*1.2

[0021] wherein P ′ represents the preset first pressure, P1 represents the saturated pressure corresponding to the highest heating temperature, and ΔP represents the pressure loss along the pipeline during the LNG submersible pump to LNG gas dispenser delivery process.

[0022] Compared with the prior art, the LNG temperature regulating device provided by the application has the advantages and beneficial effects that the LNG temperature regulating device can pre-cool the connecting pipeline and components from the LNG immersion pump to the LNG dispenser before filling, so as to avoid the rapid gasification of LNG caused by the hot pipeline and components at the initial stage of filling. After the LNG immersion pump is started, the outlet pressure of the LNG immersion pump is adjusted to be higher than the saturation pressure corresponding to the liquid temperature and is maintained stable, so that only temperature rise but no gasification occurs in the conveying process, and the gasification in the conveying process is inhibited. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 FIG. 1 is a structural schematic diagram of one embodiment of the LNG temperature regulating device without phase change. DETAILED DESCRIPTION

[0024] Before the specific embodiment of the application is described, the overall concept of the application is described as follows:

[0025] The application is mainly developed for the LNG filling process. At present, the LNG heating is usually performed by using an air temperature type heater. The conventional heater uses finned tubes, and the heating efficiency is high. Meanwhile, during the heating process, part of the LNG changes from liquid state to gaseous state, that is, phase change occurs. The LNG pumped out by the LNG immersion pump will absorb heat along the way through the gasifier and the pipeline. The pressure of the LNG at the outlet is lower than the saturation pressure of the LNG at the temperature, and the heat absorption of the LNG will cause gasification, that is, phase change. Once the LNG heated by the LNG air temperature type heater produces gas, it is difficult to remove the gas in the pipeline by using process means. The LNG dispenser uses a mass flow meter to measure, and when the gaseous content in the medium exceeds the standard, the measurement accuracy will be affected, and the dispenser will not start filling.

[0026] The inventor finds that the main reason for the above problems is the phase change in the LNG heating process. Therefore, the application provides an LNG temperature regulating device without phase change, which comprises an LNG storage device, an LNG filling device and an LNG dispenser, and heats the LNG to the temperature used by the LNG fuel vehicle. The LNG heating process does not produce phase change, and meets the requirement of the LNG dispenser on the gaseous content.

[0027] After the overall concept of the application is introduced, in order to make the purpose, technical scheme and advantages of the application more clear and explicit, the application is further described in detail by means of specific embodiments and the accompanying drawings.

[0028] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of this specification should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in one or more embodiments of this specification do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] For ease of understanding, the terms used in the embodiments of this invention are explained below:

[0030] LNG: Liquefied Natural Gas, mainly composed of methane, is widely recognized as the cleanest fossil fuel on Earth. It is colorless, odorless, non-toxic, and non-corrosive. Its volume is approximately 1 / 625th that of the same amount of gaseous natural gas, and its mass is only about 45% of that of the same volume of water.

[0031] Saturation pressure: When LNG is stored in a closed, insulated container, it often exists as a boiling liquid and is in a state of temperature-pressure equilibrium, that is, in a saturated state. The pressure of the gas phase space in the saturated state is the saturation pressure. As the temperature of LNG rises, its saturation pressure will also increase.

[0032] Adjusting saturation pressure: Adjusting saturation pressure is achieved by heating the LNG to increase its temperature, which breaks the gas-liquid equilibrium. The LNG will then accelerate its vaporization until a new equilibrium is reached, at which point the LNG saturation pressure will also increase accordingly.

[0033] LNG dispenser metering requirements: LNG dispensers use mass flow meters for metering. To ensure metering accuracy, the gas content in the metered LNG must be below the limit before dispensing can proceed.

[0034] The reference signs in the drawings of the specification include: LNG liquid storage device (1), LNG liquid tank (11), root valve (12), LNG filling device (2), vacuum pump pool (21), LNG immersed pump (22), air temperature heater (23), pressure transmitter (210), first temperature transmitter (211), second temperature transmitter (212), first pneumatic stop valve (213), second pneumatic stop valve (214), third pneumatic stop valve (215), LNG gas dispenser (3).

[0035] The technical solutions in the present application will be described clearly and completely below in combination with the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0036] Embodiment one

[0037] As shown in the figure, an LNG temperature regulating device without phase change is provided, which comprises: LNG liquid storage device (1), LNG filling device (2) and LNG gas dispenser (3); the LNG liquid storage device (1) is connected with the LNG filling device (2) and the LNG gas dispenser (3) respectively. Figure 1 The LNG liquid storage device (1) is used for storing LNG solution, which comprises: LNG liquid tank (11), root valve (12) and first connecting pipeline. The first connecting pipeline is divided into four groups, which are liquid phase pipeline, gas phase pipeline, upper liquid inlet pipeline and lower liquid inlet pipeline, and a root valve (12) is arranged on each group of first connecting pipeline; one end of the liquid phase pipeline is connected with the LNG liquid tank (11), and the other end is connected with the liquid inlet of the vacuum pump pool (21) in the LNG filling device; one end of the gas phase pipeline is connected with the LNG liquid tank (11), and the other end is connected with the gas return port of the vacuum pump pool (21) in the LNG filling device (2); one end of the upper liquid inlet pipeline and the lower liquid inlet pipeline is connected with the LNG liquid tank (11), and the other end is connected with the gas filling circulation pipeline of the LNG filling device (2) after being collected.

[0038] The LNG filling device (2) is used for regulating the temperature of the LNG solution, which comprises: vacuum pump pool (21), LNG immersed pump (22), air temperature heater (23), pressure transmitter (210), first temperature transmitter (211), second temperature transmitter (212), first pneumatic stop valve (213), second pneumatic stop valve (214), third pneumatic stop valve (215) and second connecting pipeline, and the second connecting pipeline comprises: liquid inlet pipeline, inlet collection pipe and outlet collection pipe.

[0039]

[0040] ​LNG submersible pump (22) is installed in vacuum pump pool (21), vacuum pump pool (21) has three groups of interfaces: liquid inlet, gas return and pump outlet; The liquid inlet of vacuum pump pool (21) is connected to the liquid phase pipeline of LNG storage tank (11); The gas return of vacuum pump pool (21) is connected to the gas phase pipeline of LNG storage tank (11); The pump outlet of vacuum pump pool (21) is connected to the liquid addition pipeline;

[0041] LNG filling device (2) is provided with three groups of liquid addition pipelines. The liquid addition pipelines are divided into three groups in the middle, one group is a bypass pipeline, which is provided with a first pneumatic stop valve (213), and the other two groups are heating pipelines, which are provided with an air temperature heater (23), a second pneumatic stop valve (214) and a third pneumatic stop valve (215); Three groups of liquid addition pipeline inlets are collected in an inlet collection pipe, and the inlet collection pipe is connected with the pump outlet of vacuum pump pool (21); Three groups of liquid addition pipeline outlets are collected in an outlet collection pipe, and the outlet collection pipe is connected with the liquid inlet of LNG dispenser (3); A pressure transmitter (210) and a first temperature transmitter (211) are arranged on the inlet collection pipe; The other end of the heating pipeline is connected with a second temperature transmitter (212), and the second temperature transmitter (212) is connected with the outlet collection pipe;

[0042] LNG filling device (2) is provided with a group of gas filling circulation pipelines. One end of the gas filling circulation pipeline is connected with the upper and lower liquid inlet pipelines of LNG storage tank (11), and the other end is connected with the gas return of LNG dispenser (3).

[0043] LNG dispenser (3) is used for gas filling operation of LNG solution, including liquid inlet and gas return; The liquid inlet is connected with the outlet collection pipe of LNG filling device (2); The gas return is connected with the gas filling circulation pipeline of LNG filling device (2).

[0044] Example two

[0045] A LNG temperature adjusting method without phase change, which is adjusted by the LNG temperature adjusting device without phase change in example one, including the following steps:

[0046] Before LNG filling, LNG submersible pump (22) is started to circulate, through the outlet header to LNG dispenser (3), and then through the gas filling circulation pipeline to the lower inlet of LNG storage tank (11), to precool the air temperature heater (23) and the connected pipeline. When the first temperature T1 collected by the first temperature transmitter (211) at the outlet of the pump is greater than or equal to the preset first temperature threshold, and the second temperature T2 collected by the second temperature transmitter (212) at the outlet of the air temperature heater (23) is greater than or equal to the preset second temperature threshold, the precooling is completed, and the precooling operation is stopped. In this embodiment, the first temperature threshold is -155℃, and the second temperature threshold is -115℃, that is, when T1≥-155℃ and T2≥-115℃, the precooling is completed.

[0047] After the precooling is completed, the LNG submersible pump (22) is switched to the liquid filling mode under the condition of maintaining the outlet pressure. When the third temperature T3 collected by the first temperature transmitter (211) at the outlet of the pump is greater than or equal to the preset third temperature threshold and less than the preset fourth temperature threshold, in this embodiment, the third temperature threshold is -155℃, and the fourth temperature threshold is -140℃. The temperature difference ΔT is calculated, ΔT=T1 ′ -T3=-140℃-T3; T1 ′ The fourth temperature threshold is represented by T3, and the third temperature is represented by T3. When the temperature difference is less than or equal to the preset fifth temperature threshold, in this embodiment, the fifth temperature threshold is 7.5, that is, ΔT≤7.5, single heating is started, and the second pneumatic stop valve (214) or the third pneumatic stop valve (215) is opened; when the temperature difference is greater than the preset fifth temperature threshold, that is, ΔT>7.5, double heating is started, and the second pneumatic stop valve (214) and the third pneumatic stop valve (215) are opened; when the third temperature T3 is greater than or equal to the preset fourth temperature threshold, in this embodiment, the fourth temperature threshold is -140℃, that is, T3≥-140℃, the bypass is opened, and the first pneumatic stop valve (213) is opened.

[0048] During the liquid filling process, frosting of the LNG dispenser (3) can cause the heating efficiency to decrease. The outlet temperature of the air temperature heater (23) needs to be continuously detected. When the fourth temperature T4 collected by the second temperature transmitter (212) is less than the preset sixth temperature threshold, that is, T4≤-140℃, in this embodiment, the sixth temperature threshold is -140℃, when the heating mode at this time is single heating, the single heating is automatically switched to double heating, and when the heating mode at this time is double heating, the temperature adjustment state of the LNG storage tank (11) is started.

[0049] The pre-cooling and liquid feeding process, the LNG submersible pump (22) is started by the frequency converter to adjust the speed, to adjust the pump outlet pressure and make it stable. The preset first pressure P ′ =(P1+ΔP)*1.2, P ′ represents the preset first pressure, P1 represents the corresponding saturation pressure when the highest heating temperature is -132.5℃, and ΔP represents the pressure loss along the pipeline during the LNG submersible pump to the LNG dispenser conveying process, P ′ is calculated as 0.9MPa. When the pressure P collected by the pressure transmitter (210) arranged at the LNG submersible pump (22) outlet is less than P ′ , the pump frequency is adjusted to adjust the pressure, and when the pressure P is greater than or equal to P ′ , the liquid feeding operation is performed, and the pump frequency is stabilized. To ensure that the LNG during the LNG submersible pump (22) to the LNG dispenser (3) conveying process has sufficient supercooling degree (i.e. cavitation allowance, that is, the part of the pressure higher than the saturation pressure), the heat absorption during the conveying process only causes temperature rise but not gasification.

[0050] The present application has the following beneficial effects:

[0051] Firstly, the connecting pipeline and components from the LNG submersible pump to the LNG dispenser are pre-cooled before filling, to avoid rapid gasification of the LNG caused by the hot pipeline and components at the initial stage of filling. Before the LNG filling, the LNG is pre-cooled by the LNG submersible pump pressurization and the LNG dispenser circulation pipeline returning to the storage tank. The LNG is circulated through the LNG submersible pump→the air-heating heater→the LNG dispenser→the LNG storage tank. When the air-heating heater is gasified and the LNG temperature reaches the set temperature, the pre-cooling is completed.

[0052] Secondly, a gasifier (air-heating heater) with slow heating speed is designed to avoid rapid gasification caused by rapid heating. Firstly, the stainless steel winding tube is used for the LNG air-heating heater heating pipe, and the heat exchange efficiency is lower than that of the aluminum alloy fin. Secondly, due to the large flow rate of the LNG submersible pump outlet, at least three groups of winding tubes are arranged in parallel for each route of the air-heating heater, to divide the flow into thin streams for heating to ensure sufficient heating.

[0053] Thirdly, after the LNG submersible pump is started, the LNG submersible pump outlet pressure is adjusted to be higher than the saturation pressure corresponding to the liquid temperature and to be maintained stable, so that only temperature rise but not gasification occurs during the conveying process, to inhibit the gasification during the conveying process. The LNG submersible pump outlet is provided with a pressure transmitter, and the LNG submersible pump outlet pressure is adjusted after the LNG submersible pump is started during the pre-cooling, to stabilize the LNG submersible pump outlet pressure at a certain value. The LNG submersible pump outlet pressure value is based on the sum of the saturation pressure corresponding to the highest liquid temperature after heating and the pressure loss of the pipeline from the LNG submersible pump outlet to the LNG dispenser, and a certain allowance is considered. After the LNG dispenser pre-cooling is completed, the liquid feeding mode is switched, and the liquid feeding mode is also adjusted according to the pump outlet pressure.

[0054] It should be understood by those of ordinary skill in the art that the discussion of any embodiment is merely exemplary and not intended to limit the scope of the application (including the claims) to these examples; the technical features between the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the embodiments of the application as described above, which are not provided in details for the sake of brevity.

[0055] Although the present application has been described in connection with the preferred embodiments thereof, many modifications, substitutions, and alterations, thereof, will be readily apparent to those of ordinary skill in the art, based on the foregoing description.

[0056] The embodiments of the present application are intended to cover all such alternatives, modifications, and variations as come within the scope of the broadest possible interpretation of the appended claims. Accordingly, any and all such alternations, modifications, equivalents, improvements and the like are intended to be encompassed by the present application.

Claims

1. An LNG temperature control device that does not produce a phase change, characterized in that, include: LNG storage units, LNG refueling units, and LNG dispensers; The LNG storage device is connected to the LNG refueling device and the LNG dispenser, respectively. The LNG storage device is used to store LNG solution. The LNG refueling device includes an LNG submersible pump and an ambient temperature heater for temperature control of the LNG solution. The LNG dispenser is used to add gas to the LNG solution; The LNG storage device includes an LNG storage tank, a root valve, and a first connecting pipe. The first connecting pipe consists of four sets: a liquid phase pipe, a gas phase pipe, an upper inlet pipe, and a lower inlet pipe. Each set of the first connecting pipes is equipped with a root valve. One end of the liquid phase pipe and the gas phase pipe are connected to the LNG storage tank, and the other end is connected to the LNG refueling device. One end of the upper inlet pipe and the lower inlet pipe are connected to the LNG storage tank, and the other ends converge and connect to the LNG dispenser. The LNG refueling device further includes: a vacuum pump tank, a pressure transmitter, a first temperature transmitter, a second temperature transmitter, a first pneumatic shut-off valve, a second pneumatic shut-off valve, a third pneumatic shut-off valve, and a second connecting pipe, wherein the second connecting pipe includes a liquid filling pipe, an inlet manifold, and an outlet manifold. The LNG submerged pump is installed in the vacuum pump pool, which has three sets of interfaces: a liquid inlet, a gas return inlet, and a pump outlet; the other end of the liquid inlet is connected to the liquid phase pipeline of the LNG storage device; the other end of the gas return inlet is connected to the gas phase pipeline of the LNG storage device. The refueling device is equipped with three sets of liquid refueling pipelines. One set is a bypass pipeline with a first pneumatic shut-off valve installed on it. The other two sets are heating pipelines with a second pneumatic shut-off valve and a third pneumatic valve installed on them. The inlets of the three sets of liquid refueling pipelines converge at the inlet confluence pipe, which is connected to the pump outlet of the vacuum pump tank. The other end of the heating pipeline is connected to the ambient air heater. The pressure transmitter and the first temperature transmitter are installed on the inlet confluence pipe. The outlets of the three sets of liquid refueling pipelines converge at the outlet confluence pipe, which is connected to the LNG dispenser. The second temperature transmitter is installed on the outlet confluence pipe. The LNG refueling device is equipped with a set of gas refueling circulation pipes. One end of the gas refueling circulation pipe is connected to the upper liquid inlet pipe and the lower liquid inlet pipe, and the other end is connected to the LNG refueling machine.

2. The LNG temperature control device that does not produce a phase change according to claim 1, characterized in that, The LNG dispenser includes a liquid inlet and a gas return inlet; The liquid inlet is connected to the outlet manifold of the LNG refueling device; the gas return port is connected to the gas refueling circulation pipeline of the LNG refueling device.

3. A method for temperature control of LNG without phase change, characterized in that, An LNG temperature control device that does not produce a phase change according to any one of claims 2, comprising: The LNG submerged pump is started for precooling operation. In response to the first temperature of the first temperature transmitter being greater than or equal to a preset first temperature threshold and the second temperature of the second temperature transmitter being greater than or equal to a preset second temperature threshold, the precooling operation is stopped. The LNG submersible pump is activated in the filling mode. In response to the third temperature of the first temperature transmitter being greater than or equal to a preset third temperature threshold and less than a preset fourth temperature threshold, the temperature difference is calculated. In response to the temperature difference being less than or equal to a preset fifth temperature threshold, single-path heating is activated, and the second or third pneumatic shut-off valve is opened. In response to the temperature difference being greater than the preset fifth temperature threshold, dual-path heating is activated, and the second and third pneumatic shut-off valves are opened. In response to the third temperature of the first temperature transmitter being greater than or equal to the preset fourth temperature threshold, bypass is activated, and the first pneumatic shut-off valve is opened. In response to the fourth temperature of the second temperature transmitter being less than a preset sixth temperature threshold, and in response to the heating mode being single-path heating, single-path heating is switched to dual-path heating. In response to the heating mode being dual-path heating, the LNG storage tank temperature adjustment state is activated. Calculate a preset first pressure; if the pressure of the pressure transmitter is less than the preset first pressure, adjust the pressure of the pressure transmitter via the LNG submersible pump; if the pressure of the pressure transmitter is greater than or equal to the preset first pressure, perform a liquid addition operation.

4. The LNG temperature control method without phase change according to claim 3, characterized in that, Also includes: The temperature difference is calculated using the following formula: ΔT=T1 ′ -T3 Where ΔT represents the temperature difference, T1 ′ T1 represents the preset fourth temperature threshold, and T3 represents the third temperature.

5. The LNG temperature control method without phase change according to claim 3, characterized in that, Also includes: The preset first pressure is calculated using the following formula: P ′ =(P1+ΔP)*1.2 Among them, P ′ P1 represents the preset first pressure, P1 represents the saturation pressure corresponding to the highest heating temperature, and ΔP represents the pressure loss along the flow path from the LNG submersible pump to the LNG refueling unit.

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