A natural gas transfer system and a natural gas transport tank hydrate intelligent prevention and control method

Abstract

The present invention discloses an intelligent prevention and control method for hydrates in a natural gas transport tank, which belongs to the field of natural gas gathering and transportation technology in ground engineering. The intelligent prevention and control method for hydrates in a natural gas transport tank comprises a gas storage tank; a transport vehicle having an engine and an exhaust pipe; a transport tank; a heat-conducting pipe, the heat-conducting pipe comprising a first portion provided on the transport tank and a second portion provided on the engine and / or the exhaust pipe, the first portion and the second portion being configured to be separable and forming a heat exchange loop after docking; and a control component. By arranging the heat-conducting pipe based on the transport tank, the engine and / or the exhaust pipe in the transport vehicle loaded with the transport tank, and based on the heat exchange loop formed by the heat-conducting pipe, the engine and / or the exhaust pipe can be selectively transferred to the transport tank, so that the temperature of the transport tank is higher than the chemical reaction temperature during the inflation process, thereby preventing the formation of hydrates during the inflation process.

Description

Technical Field

[0001] The present invention belongs to the technical field of natural gas gathering and transportation in ground engineering, and specifically relates to a natural gas transfer system and an intelligent hydrate prevention and control method for transporting tank bodies. Background Art

[0002] During the production of oil and gas wells, a certain amount of natural gas will be produced. In the past, the treatment method of associated gas was mainly to discharge or ignite it, which resulted in the problem of natural gas waste and caused serious pollution to the environment. The associated gas produced by some domestic oil fields is mainly utilized by gas-fired power generation and CNG recovery technology. However, the low efficiency of gas-fired generators and the complex process of CNG technology, as well as the high investment and operating costs, have restricted the recovery of small amounts of natural gas. 3 Taking small amounts of scattered natural gas below the scale of / d as an example, when a small generator set with a power generation efficiency of 25%-30% is used for ignition and power generation, most of the input energy is lost in the form of heat; according to existing measurement results, CNG recovery technology is only economically beneficial for the recovery of large amounts of natural gas.

[0003] Based on the existing CNG technology, there is a natural gas transfer system for recycling mixed gas. The main operation process of the system is as follows: first, the associated gas generated by the oil and gas well is stored in the gas tank after gravity separation of impurities, compression and pressure increase. When the gas content in the gas tank reaches the predetermined pressure, a truck carrying the transport tank is mounted to go to the site for filling. The gas in the gas tank is directly or re-compressed and then transported to the transport tank. After filling to the predetermined pressure, the natural gas is transported to the designated location. However, during this process, the temperature in the gas tank will increase sharply when the gas tank is filled with gas from the transport tank. Reduce, there is a risk of generating hydrates to block the pipeline or pipe mouth when filling cold air into the transport tank, which is particularly obvious in winter when the ambient temperature is low. In the existing technology, this problem is generally solved by heating, but heating causes the internal pressure of the gas tank to rise. Under the influence of the design pressure of the gas tank, the gas storage volume needs to be reduced, affecting production efficiency; at the same time, a large amount of energy is consumed when heating the gas tank, affecting the economic benefits of recycling; finally, after heating to the specified temperature, the gas tank needs to be insulated or continued to be heated to maintain the temperature. This process consumes material or energy and also affects the economic benefits of recycling. Summary of the Invention

[0004] The purpose of the present invention is to provide an intelligent hydrate prevention and control method for natural gas transportation tanks to solve the problems in the natural gas transportation process raised in the above background technology.

[0005] To achieve the above objectives, the present invention provides the following technical solutions: a method for intelligently preventing and controlling hydrates in natural gas transportation tanks, the system comprising:

[0006] Gas storage tank, which stores gas to be transported;

[0007] a hauling vehicle body having an engine and an exhaust duct;

[0008] A transport tank body is loaded on the transport vehicle body and is configured to receive the gas to be transported in the gas storage tank body;

[0009] a heat-conducting pipe body, the heat-conducting pipe body comprising a first portion disposed on the transport tank body and a second portion disposed on the engine and / or exhaust pipe, the first portion and the second portion being configured to be separable and forming a heat exchange circuit after docking;

[0010] The control component is configured to control the opening and closing of the heat exchange loop and the transfer of the gas to be transported between the gas storage tank and the transport tank.

[0011] Preferably, the system further comprises:

[0012] A measuring assembly is configured to obtain pressure and temperature data of the transported tank.

[0013] Preferably, the system further comprises:

[0014] Two heat conducting sheets are respectively assembled on the butt ends of the first part and the second part;

[0015] At least one driving structure is configured to move the heat conducting sheet so as to dock or separate the first portion and the second portion.

[0016] Preferably, the gas to be transported is transferred between the gas storage tank and the transport tank through a pipeline, and a solenoid valve controlled by a control component is installed on the pipeline.

[0017] Preferably, the control component includes a controller and a control terminal, and the controller and the control terminal are communicatively connected.

[0018] Preferably, the heat-conducting pipe body is composed of a metal shell and a liquid medium encapsulated in the metal shell.

[0019] A method for intelligently preventing and controlling hydrates in natural gas transport tanks is provided, the method being implemented based on the above-mentioned system and comprising:

[0020] Obtain the temperature and pressure relationship when the gas to be transported forms hydrates;

[0021] Calculate the inflation pressure and inflation temperature of the air tank after inflation is completed;

[0022] Substitute the inflation pressure into the relationship to obtain the combination temperature, and compare the inflation temperature to the combination temperature;

[0023] When the inflation temperature is lower than the combination temperature, the heat exchange circuit is opened at least in a part of the section during transportation and / or the heat of the transportation tank is supplemented at the inflation site.

[0024] Preferably, when the inflation temperature is lower than the combination temperature, opening the heat exchange circuit at least in a portion of the transportation section and / or supplementing heat to the transportation tank at the inflation site includes:

[0025] Calculate the heat exchange amount that the transport vehicle obtains when the heat exchange circuit is fully opened during the transport process;

[0026] Calculate the heat required to raise the gas to be transported in the transport tank from the charging temperature to the combination temperature;

[0027] Based on the difference between the heat exchange heat and the lifting heat, the opening and closing of the heat exchange circuit during transportation and the replenishment of heat at the inflation site are controlled.

[0028] Preferably, the control of opening and closing of the heat exchange circuit during transportation and whether to supplement heat at the aeration site based on the difference between the heat exchange heat and the lifting heat includes:

[0029] When the heat exchange amount is greater than the lifting amount, the heat exchange circuit is controlled to be opened in some sections during the transportation process;

[0030] When the heat exchange amount is equal to the heat increase amount, the heat exchange circuit is controlled to be open during the entire transportation process;

[0031] When the heat exchange amount is less than the lifting heat, the heat exchange circuit is controlled to be open throughout the transportation process and heat supplement is started at the inflation site.

[0032] Preferably, the method further comprises:

[0033] The temperature of the transported tank is monitored on the return journey, and the heat exchange circuit is opened when the temperature is lower than the set value.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present application arranges heat-conducting pipes based on the towing tank, engine and / or exhaust pipe in the towing vehicle loaded with the towing tank, and based on the heat exchange circuit formed by the heat-conducting pipes, can selectively transfer the heat of the engine and / or exhaust pipe to the towing tank, so that the temperature of the towing tank is higher than the chemical reaction temperature during the inflation process, so as to prevent the formation of hydrates during the inflation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The overall schematic diagram of the transfer system;

[0037] Figure 2 Schematic diagram of the pulling vehicle body;

[0038] Figure 3 This is a schematic diagram of the transfer system control;

[0039] Figure 4 is a schematic diagram of the heat exchange circuit;

[0040] Figure 5 Method flow Figure 1 ;

[0041] Figure 6 Method flow Figure 2 .

[0042] In the picture:

[0043] 100. Gas storage tank body;

[0044] 200, hauling vehicle body; 201, engine; 202, exhaust pipe;

[0045] 300. Transporting tanks;

[0046] 400, heat pipe body; 401, first part; 402, second part; 403, first heat conducting plate; 404, second heat conducting plate; 405, driving structure;

[0047] 500, temperature sensor; 501, pressure sensor; 502, solenoid valve;

[0048] 600, controller; 601, control terminal; 602, network communication equipment. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] This application provides a natural gas transfer system. Figure 1-4 The system includes a gas storage tank 100, which is configured to store natural gas to be transported (hereinafter referred to as "to-be-transported gas"). The to-be-transported gas is obtained by gravity separation of impurities, compression and pressure-increasing of associated gas generated by oil and gas wells;

[0051] The system further includes a transport vehicle 200, which is configured as a natural gas transport vehicle. That is, the transport vehicle 200 is loaded with at least one transport tank 300 containing natural gas. Exemplarily, the transport tank 300 is configured as a long bundle tank. The number and volume of the transport tanks 300 (e.g., parameters such as length and bottom diameter) are configured based on the carrying capacity of the transport vehicle 200 and the gas storage capacity of the gas storage tank 100. That is, the number and volume of the transport tanks 300 are adapted to the carrying capacity of the transport vehicle 200 and the gas storage capacity of the gas storage tank 100. Furthermore, the transport vehicle 200 also has an engine 201 and an exhaust pipe 202.

[0052] Furthermore, the above-mentioned transport tank body 300 is connected to the gas storage tank body 100 through a pipeline, and a solenoid valve 502 is provided on the pipeline. When the transport tank body 300 is transported to the position of the gas storage tank body 100 along with the transport vehicle body 200, the transport tank body 300 and the gas storage tank body 100 are connected through the pipeline, and the solenoid valve 502 is opened, and the gas to be transported in the gas storage tank body 100 is transferred to the transport tank body 300.

[0053] Reference Figure 1 and 2 The system further includes a heat-conducting pipe body 400, which is provided based on the above-mentioned transport vehicle body 200 and configured to perform heat exchange with the components (such as the transport tank body 300) in the transport tank body 300. In some embodiments, the heat-conducting pipe body 400 is composed of a metal shell and a heat-conducting medium provided in the metal shell. For example, the heat-conducting pipe body 400 is formed by encapsulating a liquid medium in an aluminum shell. Figure 4The above-mentioned heat-conducting tank body has a first portion 401 provided on the hauling tank body 300 and a second portion 402 provided on the engine 201 and / or the exhaust pipe 202. In some examples, the above-mentioned exhaust pipe 202 is arranged on the hauling tank body 300, the engine 201 and / or the exhaust pipe 202 in a winding manner to increase the contact area between the exhaust pipe 202 and the hauling tank body 300, the engine 201 and / or the exhaust pipe 202. During the operation (driving) of the gas-hauling vehicle body, the engine 201 of the hauling vehicle body 200 runs and starts to heat up, and the high-temperature exhaust gas generated by the operation is discharged through the exhaust pipe 202, that is, the second portion 402 in the heat-conducting pipe body 400 is in a high-temperature environment The liquid medium in the second portion 402 absorbs heat and then vaporizes, and flows to the low-temperature end (such as the first portion 401). Correspondingly, the first portion 401 of the heat-conducting pipe body 400 is in the environment. When the vaporized medium in the first portion 401 moves to the position of the first portion 401, the vaporized medium is cooled and liquefied, releasing heat. The liquefied medium flows back to the high-temperature end (such as the second portion 402) due to capillary action. At the same time, the released heat is transferred to the transport tank body 300 and causes it to heat up. Through the above process, heat exchange can be achieved between the transport tank body 300 and the engine 201 and / or the exhaust pipe body, that is, the first portion 401 and the second portion 402 of the heat-conducting pipe body 400 constitute a complete heat exchange circuit.

[0054] Furthermore, in some embodiments, the first portion 401 and the second portion 402 of the heat-conducting pipe body 400 are configured to be separable and dockable, so as to correspondingly control the opening and closing of the heat exchange circuit, and thereby control whether heat is exchanged between the transport tank body 300 and the engine 201 and / or the exhaust pipe body, that is, to control the heat exchange process. In some examples, the docking ends of the first portion 401 and the second portion 402 of the heat-conducting pipe body 400 are respectively recorded as the first docking end and the second docking end, and the first heat-conducting plate 403 and the second heat-conducting plate 404 are correspondingly installed at the first docking end and the second docking end. The first heat-conducting plate 403 and the second heat-conducting plate 404 are driven by an external driving structure 405 to make the first heat-conducting plate 403 and the second heat-conducting plate 404 fit together. Or separated, in some examples, the contact surface of the first thermally conductive sheet 403 and the second thermally conductive sheet 404 is constituted by a thermally conductive silicone sheet, and the driving structure 405 is constituted by a push-type electric device, and accordingly, the first thermally conductive sheet 403 and the second thermally conductive sheet 404 perform linear motion; in some embodiments, the system further includes a force sensor, which is placed on the thermally conductive silicone between the first thermally conductive sheet 403 and the second thermally conductive sheet 404, and the degree of fit of the contact surface of the first thermally conductive sheet 403 and the second thermally conductive sheet 404 is judged based on the pressure data detected by the force sensor, to ensure that the first thermally conductive sheet 403 and the second thermally conductive sheet 404 are tightly fitted when in contact, thereby improving the thermal conductivity of the first thermally conductive sheet 403 and the second thermally conductive sheet 404 when in contact.

[0055] The above system also includes a measuring component, which is configured to obtain pressure and temperature data of the transport tank body 300. In some examples, the measuring component includes a temperature sensor 500 and a pressure sensor 501. In some examples, the above temperature sensor 500 uses a thermistor (such as a PT100 thermistor) whose resistance is proportional to the temperature. The resistance of the thermistor is minimum when the temperature is 0°C and reaches a maximum when the temperature is 100°C. Based on the proportional relationship, the corresponding relationship between the internal resistance value and temperature in the range of 0-100°C can be obtained. When in use, the temperature value of the transport tank body 300 can be obtained through the resistance value of the measuring device.

[0056] Reference Figure 3 The system further includes a control component, which includes a controller 600 (such as a PLC) and a control terminal 601 (such as a computer), wherein the controller 600 is configured to communicate with the control terminal 601, for example, to send data information to the control terminal 601 and receive instructions from the control terminal 601. For example, the system further includes a network communication device 602, and the controller 600 and the control terminal 601 communicate based on the network communication device 602. At the same time, the controller 600 can receive signals from the temperature sensor 500 and the pressure sensor 501 and convert them into temperature and pressure data. At the same time, the controller 600 can control the opening and closing of the solenoid valve 502 on the docking pipeline of the gas storage tank body 100 and the transport tank body 300, so as to To control the transfer operation of the gas to be transported, the above-mentioned control terminal 601 mainly has the following functions: 1. Receive the temperature and pressure data of the transport tank 300 in real time (such as receiving it through the network communication device 602), and display the data on the screen for the staff to view; 2. Use commercial software such as PTVsim to calculate the temperature and pressure conditions for the formation of hydrates of natural gas with different components according to the properties of natural gas fluid, output the temperature and pressure phase diagram of the hydrate for personnel to view, and send the temperature and pressure data to the controller 600 (such as sending it through the network communication device 602); 3. Use software to simulate the process of filling the upstream gas storage tank 100 with natural gas to the transport tank 300, obtain the temperature and pressure of the transport tank after the filling is completed, and transmit the data to the controller 600 (such as through the network transmission device).

[0057] A method for intelligent prevention and control of 300 hydrate in natural gas transport tanks, referring to Figure 5 and 6 , including the following steps:

[0058] S100: Obtaining a temperature and pressure relationship when the gas to be transported forms hydrates;

[0059] In step S100, the temperature and pressure relationship when the gas to be transported generates hydrates is obtained based on the commercial software installed on the control terminal 601. In particular, when the natural gas composition information of the gas to be transported is incomplete, methane is used as the gas to be transported for calculation, and the temperature and pressure relationship corresponding to the formation of hydrates by methane is obtained.

[0060] S200: Calculating the inflation pressure and inflation temperature of the air tank after inflation is completed;

[0061] In step S200, the calculation of the inflation pressure and inflation temperature of the pulling tank body after inflation is completed is based on the volume, pressure, and temperature data of the gas storage tank body 100 and the volume, pressure, and temperature data of the pulling tank body 300. That is, when calculating the inflation pressure and inflation temperature of the pulling tank body 300 after inflation is completed through software simulation, it is first necessary to obtain the temperature and pressure data of the gas storage tank body 100 and the temperature and pressure data of the pulling tank body 300. The temperature and pressure data of the pulling tank body 300 can be obtained through the measurement components in the system (such as the pressure sensor 501 and the temperature sensor 500), and the temperature and pressure of the gas storage tank body 100 can also be measured by the pressure sensor 501. Furthermore, in step S200, the simulation calculation of the inflation process follows the Peng-Robinson equation calculation model, which is as follows:

[0062]

[0063] make

[0064] A=aP / (RT) 2 (2)

[0065] B=bP / RT (3)

[0066] V=ZRT / P (4)

[0067] The above equation can be written as a cubic equation represented by the compression factor Z:

[0068] Z 3 -(1-B)Z 2 +(A-3B 2 -2B)Z-(AB-B 2 -B 3 )=0 (5)

[0069] Where b = 0.0778RT c / P c ; a is a function of temperature, a=a c a0.

[0070] a c =0.45724(RTc ) 2 / P c (6)

[0071]

[0072] m=0.37464+1.54226ω-0.26992ω 2 (8)

[0073] Where P is the pressure of the system, in MPa; T is the temperature of the system, in K; V is the molar volume of the component, in cm 3 / mol; Z is the compressibility factor; R is the ideal gas constant, which is 8.314 J / (mol·K); P c is the critical pressure of the component, in MPa; T c is the critical temperature of the component, in K; the compressibility factor Z value can be solved by iterative method.

[0074] In step S400, when the inflation temperature is lower than the combination temperature, opening the heat exchange circuit at least in a portion of the transportation section and / or supplementing heat to the transportation tank at the inflation site specifically includes:

[0075] The heat exchange amount obtained by the transport vehicle 200 when the heat exchange circuit is fully opened during the transport process to transport the tank 300 is calculated;

[0076] Calculate the heat required to raise the gas to be transported in the transport tank from the charging temperature to the combination temperature;

[0077] Based on the difference between the heat exchange heat and the lifting heat, the opening and closing of the heat exchange circuit during transportation and the replenishment of heat at the inflation site are controlled.

[0078] Specifically, the heat exchange amount obtained by the transport vehicle 200 when the heat exchange circuit is fully opened during the transport of the tank 300 includes:

[0079] The heat released by complete combustion of each liter of diesel is as follows:

[0080] Q1=q·ρ (9)

[0081] Where q is the calorific value of diesel, in J / kg; ρ is the density of diesel, in kg / L.

[0082] The heat generated by diesel combustion during the entire journey is as follows:

[0083] Q2=A·Q1·S (10)

[0084] Where A is the fuel consumption per kilometer of the hauling vehicle, in L / km; S is the distance of this haul, in km.

[0085] The heat transferred from the engine 201 and the exhaust pipe to the transport tank 300 along the entire road section is as follows:

[0086] Q3=(Q2-Q2·δ1)·δ2=Q2·δ2-Q2·δ1·δ2 (11)

[0087] Wherein, δ1 is the thermal efficiency of the engine 201; δ2 is the utilization rate of heat not converted into mechanical energy;

[0088] The heat required to heat the gas to be transported in the transport tank 300 from the charging temperature to the combination temperature is calculated to include:

[0089] According to the ideal gas state equation, the amount of gas in the transport tank after filling is completed is as follows:

[0090]

[0091] Where P is the pressure inside the tank, in MPa; V is the volume inside the tank, in m 3 ; R is the gas state constant; T is the temperature inside the tank, unit is K.

[0092] The heat required to heat natural gas from temperature t1 to temperature t2 is as follows:

[0093] Q4=C v ·n·M(t2-t1)·V (13)

[0094] Where C v is the constant volume specific heat capacity, in J / (g·K); M is the molar volume, in g / mol; t1 is the initial temperature, in K; t2 is the target temperature, in K.

[0095] Based on the difference between the heat exchanged and the heat increased, the opening and closing of the heat exchange circuit during transportation and the heat replenishment at the aeration site are controlled, including:

[0096] When the heat exchange amount is greater than the lifting amount, the heat exchange circuit is controlled to be opened in some sections during the transportation process;

[0097] When the heat exchange amount is equal to the heat increase amount, the heat exchange circuit is controlled to be open during the entire transportation process;

[0098] When the heat exchange amount is less than the lifting heat, the heat exchange circuit is controlled to be open throughout the transportation process and heat supplement is started at the inflation site.

[0099] Specifically, when the heat exchange amount is less than the lifting amount, the heat exchange circuit is controlled to be open during the entire transportation process and heat is supplemented at the aeration site. The heat supplemented by the upstream electric heating is as follows:

[0100] Q5=Q4-Q3 (14)

[0101] When the heat exchange amount equals the heat increase amount, the controller 600 starts the heat recovery of the hauling vehicle for the entire journey.

[0102] When the heat exchange heat is greater than the lifting heat, after this result occurs, the controller 600 calculates the heat required to ensure that no hydrates are generated in the transport tank during the filling process, and calculates the distance required to recover the former heat value based on the thermal efficiency of the engine 201. When the transport vehicle reaches the target distance, the heat recovery is stopped.

[0103] The distance traveled with the heat recovery system on is calculated as follows:

[0104]

[0105] S300: Substituting the inflation pressure into a relationship to obtain a combination temperature, and comparing the inflation temperature and the combination temperature;

[0106] In step S300, after the inflation pressure is obtained by simulation calculation in step S200, the combination temperature of the belt under the inflation pressure can be obtained based on the temperature and pressure relationship obtained in step S100;

[0107] S400: When the inflation temperature is lower than the combination temperature, a heat exchange circuit is opened at least in a portion of the transportation section and / or heat is added to the transportation tank 300 at the inflation site;

[0108] In some embodiments, the above method further comprises:

[0109] When the charging temperature is not less than the combination temperature, the corresponding control heat exchange circuit is closed during transportation.

[0110] Furthermore, the above method also includes:

[0111] The temperature of the transport tank 300 is monitored on the return journey, and the heat exchange circuit is opened when the temperature is lower than the set value.

[0112] Let's take methane as an example to illustrate:

[0113] The existing empirical formula for methane hydrate formation is as follows:

[0114] P=2.61e 0.1T (16)

[0115] Wherein, P is the pressure of hydrate formation, in MPa; T is the temperature under the corresponding pressure, in °C.

[0116] In the period of high ambient temperature (such as summer), two containers are 25m 3The gas storage tank 100 is taken as an example. At this time, the temperature of the gas storage tank 100 is 20°C and the pressure is 5Mpa. Correspondingly, the volume of the transport tank 300 is 50m 3 The initial temperature of the transport tank body 300 is 20°C, and the initial pressure is 0.5 MPa. At this time, commercial software is used to simulate the process of charging the gas storage tank body 100 into the transport tank body 300. After the simulation, the temperature of the transport tank body 300 (i.e., the charging temperature) is 13°C, and the pressure (i.e., the charging pressure) is 3 MPa. Substituting the charging pressure of 3 MPa into Formula 16, the corresponding combination temperature is 2 MPa, that is, under a pressure of 3 MPa, hydrates will only be produced when the temperature is lower than 2°C. The simulated charging temperature is greater than the combination temperature, that is, hydrates will not be produced during the charging process. At this time, there is no need to open the heat exchange circuit during transportation or to supplement the heat of the transport tank body 300 at the charging site. At the same time, on the return journey, since the transport tank body 300 is in an environment of 20°C, hydrates will not be produced, that is, there is no need to open the heat exchange circuit on the return journey.

[0117] During the period of low ambient temperature (such as winter), the lowest ambient temperature is generally -20°C. At this time, there are still two upstream gas storage tanks 100, and the volume of a single gas storage tank 100 is 25m 3 The pressure of the gas storage tank 100 is 5 MPa and the temperature is 6°C (from formula 16, it can be seen that under the pressure of 5 MPa and the temperature of 6°C, hydrates will not be produced). Correspondingly, the volume of the transport tank 300 is 20 m 3 The initial temperature of the transport tank 300 is -10°C, and the initial pressure is 0.5 MPa. The inflation process is simulated using commercial software. After the simulation, the temperature (inflation temperature) of the transport tank 300 is -1°C, and the pressure is 3 MPa. As can be seen from the above description of the summer period, the inflation temperature is lower than the combination temperature, that is, hydrates will be generated during the inflation process. In this case, it is necessary to open the heat exchange circuit during transportation and / or replenish heat for the transport tank 300 at the inflation site. The specific calculation process is as follows:

[0118] Assume that the efficiency of the engine 201 of the transport vehicle 200 is 50%, the distance traveled during the transport is 200 km, the diesel density is 0.84 kg / L, the calorific value is 4.6×107 J / Kg, the utilization rate of heat not converted into mechanical energy is 70%, and the fuel consumption per kilometer of the transport vehicle is 0.35 L / Km. In this case, if the heat exchange circuit is kept open throughout the transport, the heat value that can be recovered is:

[0119] Q 产 =200×0.84×4.6×10 7 × 0.35 × 0.5 × 0.7 = 9.47 × 10 8 J

[0120] The specific heat capacity at constant volume of methane at 3 MPa pressure and -2°C is 1.6 KJ / m 3 / K, molar mass 16.0425g / mol, molar gas constant R is 8.314J / mol / K, the amount of substance is:

[0121]

[0122] 20m 3 The heat required to raise methane from -1°C to 2°C is:

[0123] Q 需 =1.6×10 3 ×6.09×10 4 ×16.0425×3×20=9.38×10 10 J

[0124] It can be seen that the heat recovery system of the hauling vehicle is far from enough to preheat the hauling tank 300 in advance on the entire road section, and it is necessary to use electric heating at the upstream site to supplement the heat. However, the heat recovered on the entire road section is equivalent to the heat generated by the complete combustion of 1 liter of diesel. The calculation method is as follows:

[0125]

[0126] The hauler traveled 200 km and consumed about 70L of fuel. After turning on the heat recovery system, it could provide additional heat equivalent to the total combustion of 24.51L of diesel, greatly improving the utilization rate of diesel.

[0127] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A natural gas transfer system, characterized by: The system comprises: Gas storage tank, which stores the gas to be transported; a hauling vehicle body having an engine and an exhaust duct; A transport tank body is loaded on the transport vehicle body and is configured to receive the gas to be transported in the gas storage tank body; a heat-conducting pipe body, the heat-conducting pipe body comprising a first portion disposed on the transport tank body and a second portion disposed on the engine and / or exhaust pipe, the first portion and the second portion being configured to be separable and forming a heat exchange circuit after docking; A control assembly configured to control the opening and closing of the heat exchange circuit and the transfer of the gas to be transported between the gas storage tank and the transport tank; The system further comprises: Two heat conducting sheets are respectively assembled on the butt ends of the first part and the second part; at least one driving structure configured to drive the heat conducting plate to move linearly so as to dock or separate the first portion and the second portion; The heat-conducting pipe body is composed of a metal shell and a liquid medium encapsulated in the metal shell.

2. A natural gas transfer system according to claim 1, characterized in that: The system further comprises: A measuring assembly is configured to obtain pressure and temperature data of the transported tank.

3. A natural gas transfer system according to claim 1, characterized in that: The gas to be transported is transferred between the gas storage tank and the transport tank through a pipeline, and a solenoid valve controlled by a control component is installed on the pipeline.

4. A natural gas transfer system according to claim 1, characterized in that: The control component includes a controller and a control terminal, and the controller and the control terminal are communicatively connected.

5. A method for intelligent prevention and control of hydrates in natural gas transportation tanks, characterized by: The method is implemented based on the system according to any one of claims 1 to 4, and the method includes: Obtain the temperature and pressure relationship when the gas to be transported forms hydrates; Calculate the inflation pressure and inflation temperature of the air tank after inflation is completed; Substitute the inflation pressure into the relationship to obtain the combination temperature, and compare the inflation temperature to the combination temperature; When the inflation temperature is lower than the combination temperature, the heat exchange circuit is opened at least in a part of the section during transportation and / or the heat of the transportation tank is supplemented at the inflation site.

6. The intelligent hydrate prevention and control method for natural gas transportation tanks according to claim 5 is characterized by: When the inflation temperature is lower than the combination temperature, the heat exchange circuit is opened at least in a portion of the transportation section and / or heat is supplemented to the transportation tank at the inflation site, including: Calculate the heat exchange amount that the transport vehicle obtains when the heat exchange circuit is fully opened during the transport process; Calculate the heat required to raise the gas to be transported in the transport tank from the charging temperature to the combination temperature; Based on the difference between the heat exchange heat and the lifting heat, the opening and closing of the heat exchange circuit during transportation and the replenishment of heat at the inflation site are controlled.

7. The intelligent hydrate prevention and control method for natural gas transportation tanks according to claim 6 is characterized by: The control of opening and closing of the heat exchange circuit during transportation and the control of heat replenishment at the aeration site based on the difference between the heat exchange heat and the lifting heat includes: When the heat exchange amount is greater than the lifting amount, the heat exchange circuit is controlled to be opened in some sections during the transportation process; When the heat exchange amount is equal to the heat increase amount, the heat exchange circuit is controlled to be open during the entire transportation process; When the heat exchange amount is less than the lifting heat, the heat exchange circuit is controlled to be open throughout the transportation process and heat supplement is started at the inflation site.

8. The intelligent hydrate prevention and control method for natural gas transportation tanks according to claim 5 is characterized by: The method further comprises: The temperature of the transported tank is monitored on the return journey, and the heat exchange circuit is opened when the temperature is lower than the set value.

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