Disclosure of Invention
The application mainly solves the technical problems that in the prior art, the tank body cannot be conveyed in a differential pressure mode due to the fact that the air pressure value of a small terminal is larger than that of the tank body after multiple times of unloading, and the tank body is self-pressurized and then saturated pressure is increased so as to be unfavorable for unloading.
In order to solve the technical problems and achieve the purposes of the application, the application provides a pressure recovery system of an LNG distribution vehicle, which is characterized by comprising a first pressure monitoring device, a second pressure monitoring device and a pressure recovery assembly, wherein a tank body is connected with a small terminal through the pressure recovery assembly; the first pressure monitoring device is used for monitoring the pressure in the tank body, and the pressure value in the tank body is a first pressure value; the second pressure monitoring device is used for monitoring the pressure in the small terminal, and the pressure value in the small terminal is a second pressure value; the first pressure monitoring device is connected with the second pressure monitoring device through the control device and the pressure recovery assembly, and when the second pressure value is larger than the first pressure value, the pressure recovery device recovers the pressure in the small terminal into the tank body.
In an embodiment, the pressure recovery assembly comprises an air inlet pipe, an air outlet pipe and a recovery pipeline, the air inlet pipe is connected with the air outlet pipe through the recovery pipeline, the air outlet pipe is connected with the top of the small-sized terminal, the air inlet pipe is connected with the top of the tank body, the recovery pipeline is composed of a first recovery branch and a second recovery branch which are arranged in parallel, a stop valve is arranged on the first recovery branch, a compressor is arranged on the second recovery branch, a master control valve is arranged on the air outlet pipe, and the compressors are all connected with the control device.
In an embodiment, the first recovery branch is provided with a check valve, the air inlet pipe is provided with a one-way valve, and the one-way valve and the check valve control the air to flow from the small terminal to the tank.
In one embodiment, the air outlet pipe is provided with a first vaporizer.
In one embodiment, the tank is connected to a pressurizing device.
In an implementation manner, the pressurizing device comprises a first pressurizing pipe, a second pressurizing pipe and a second vaporizer, the first pressurizing pipe is connected with the second pressurizing pipe through the second vaporizer, the first pressurizing pipe is connected with the second pressurizing pipe uniformly with the tank body, the connecting point of the first pressurizing pipe and the tank body is arranged at the bottom of the tank body, the connecting point of the second pressurizing pipe and the tank body is arranged at the top of the tank body, and a pneumatic pressurizing valve is arranged on the first pressurizing pipe and connected with the control device.
In one embodiment, the tank body comprises a main tank body and a seal head, and the main tank body is welded with the seal head.
In one embodiment, the first pressure monitoring device and the second pressure monitoring device are both electronic pressure transmitters.
Compared with the prior art, the pressure recovery system of the LNG delivery vehicle has the following beneficial effects:
1. When the tank body needs to convey the liquefied natural gas to the small-sized terminal in a differential pressure conveying mode, the first pressure monitoring device monitors the pressure in the tank body and sends a monitored first pressure value to the control device, the second pressure monitoring device monitors the pressure in the small-sized terminal and sends a monitored pressure value to the control device, the control device compares the first pressure value with the second pressure value, when the second pressure value is larger than the first pressure value, the control device controls the pressure recovery assembly to recover the gaseous liquefied natural gas in the small-sized terminal into the tank body, the pressure in the small-sized terminal is reduced while the pressure in the tank body is increased, so that positive differential pressure between the tank body and the small-sized terminal is formed in an accelerating mode, and differential pressure conveying of the tank body to the liquefied natural gas in the small-sized terminal is realized;
2. the reasonable utilization of the pressure in the small terminal, namely, the pressure in the small terminal is recovered into the tank body through the pressure recovery device, the pressure in the tank body is increased, and meanwhile, the pressure in the small terminal is reduced, so that the filling speed and the filling efficiency are improved, and the filling cannot cause overpressure discharge;
3. In the prior art, the self-pressurization of the vehicle tank body needs to absorb external heat, and the pressure of the small-sized terminal is recovered into the tank body through the pressure recovery assembly, so that the external heat can be absorbed less, and the number of the unloaded vehicles is increased.
Therefore, the application has the characteristics of reasonable utilization and high efficiency.
Detailed Description
In order to make the objects, features and advantages of the present application more comprehensible, the technical solutions according to the embodiments of the present application will be clearly described in the following with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In the prior art, as the number of times of unloading increases, the saturation pressure in the tank also increases simultaneously, when the air pressure value of the small terminal 4 is greater than the air pressure value in the tank 3, the natural gas in the tank 3 is difficult to be conveyed to the small terminal 4 by a differential pressure conveying method, and when the air pressure in the tank 3 is pressurized by the pressurizing device, the value of the tank 3 required to be pressurized is correspondingly increased because the air pressure of the small terminal 4 is greater than the air pressure in the tank 3, and even the condition of overlarge pressure in the tank 3 can occur.
The application provides a pressure recovery system of an LNG distribution vehicle, which comprises a first pressure monitoring device 1, a second pressure monitoring device 2 and a pressure recovery assembly, wherein a tank body 3 is connected with a small terminal 4 through the pressure recovery assembly; the first pressure monitoring device 1 is used for monitoring the pressure in the tank body 3, and the pressure value in the tank body 3 is a first pressure value; the second pressure monitoring device 2 is used for monitoring the pressure in the small terminal 4, and the pressure value in the small terminal 4 is a second pressure value; the first pressure monitoring device 1 and the second pressure monitoring device 2 are connected with a pressure recovery component through a control device 5, and when the second pressure value is larger than the first pressure value, the pressure recovery device recovers the pressure in the small terminal 4 into the tank body 3. When the second pressure value is equal to the first pressure value, the compressor 11 is used for pumping the pressure in the small terminal 4 into the tank 3, increasing the pressure in the tank 3, reducing the pressure in the small terminal 4 and quickly forming a positive pressure difference.
Examples:
fig. 1 to 3 show one embodiment of the pressure recovery system of the LNG distribution vehicle of the present application.
The LNG delivery vehicle comprises a frame and a tank body 3, wherein the tank body 3 is arranged on the frame, and the tank body 3 is filled with liquefied natural gas, so that the liquefied natural gas delivery of small-sized terminal equipment is realized. In a specific embodiment of the application, the LNG dispensing vehicle is specifically a small LNG dispensing vehicle with a smaller capacity, preferably a small LNG dispensing vehicle with a capacity of 4m3 or 9m3 or 15m3. The small-sized LNG delivery vehicle is specially used for delivering small-sized terminals 4 with small storage capacity, and in the delivery process, the small-sized LNG delivery vehicle needs to be unloaded for multiple times, and after each unloading, the tank body 3 needs to be pressurized for next differential pressure conveying.
Referring to fig. 1 and 2, in an embodiment of the present application, a pressure recovery system of an LNG distribution vehicle is shown, which includes a pressure monitoring device, a pressure recovery assembly and a control device 5, wherein the pressure monitoring device is connected to the pressure recovery assembly through the control device 5. The pressure monitoring device is used for monitoring the air pressure of the tank body 3 and the small terminal 4, and when the natural gas in the tank body 3 needs to be conveyed to the small terminal 4 in a differential pressure conveying mode, the pressure in the tank body 3 and the pressure in the small terminal 4 are respectively monitored through the pressure monitoring device. If the pressure in the small terminal 4 is detected to be greater than the pressure in the tank 3, the pressure in the small terminal 4 is regarded as excessive. When the pressure of the small-sized terminal 4 is excessive, the tank 3 cannot supply natural gas to the small-sized terminal 4 by differential pressure supply. Only by increasing the pressure in the tank 3 and simultaneously reducing the pressure of the small terminal 4, differential pressure transmission between the tank 3 and the small terminal 4 can be rapidly realized. The control device 5 adjusts and adjusts the pressure of the tank 3 and the small terminal 4 according to the monitoring data of the pressure monitoring device, and the specific adjusting means is implemented by the pressure recovery component.
The pressure monitoring device comprises a first pressure monitoring device 1 and a second pressure monitoring device 2, wherein the first pressure monitoring device 1 is used for monitoring the pressure in the tank body 3 and recording the pressure value in the tank body 3 as a first pressure value; the second pressure monitoring device 2 is used for monitoring the pressure in the small terminal 4 and recording the pressure value of the small terminal 4 as a second pressure value.
The first pressure monitoring device 1 and the second pressure monitoring device 2 are connected with the pressure recovery device through a control device 5 in a signal connection mode. The first pressure monitoring device 1 sends a first pressure value to the control device 5 in real time, the second pressure monitoring device 2 sends a second pressure value to the control device 5 in real time, the control device 5 compares the first pressure value with the second pressure value, when the second pressure value is larger than the first pressure value, the control device 5 controls the pressure recovery component to recover the gaseous liquefied natural gas in the small-sized terminal 4 into the tank body 3, the pressure in the small-sized terminal 4 is reduced while the pressure in the tank body 3 is increased, and therefore a positive pressure difference between the tank body 3 and the small-sized terminal 4 is formed, and the tank body 3 is used for carrying the liquefied natural gas to the small-sized terminal 4 in a differential pressure mode. The positive pressure difference means that the difference between the first pressure value and the second pressure value is positive, i.e. the pressure in the tank 3 is greater than the pressure in the small terminal 4.
The pressure in the small terminal 4 is reasonably utilized, namely, the pressure in the small terminal 4 is recovered into the paper can 3 through the pressure recovery device, the pressure in the can 3 is increased, and meanwhile, the pressure in the small terminal 4 is reduced, so that the filling speed and the filling efficiency are improved, and the filling cannot cause the overpressure discharge of the small terminal and the can. If the pressure difference between the tank 3 and the small terminal 4 is directly satisfied by increasing the pressure difference of the tank 3, the pressure difference of the tank 3 may be greater than the maximum pressure difference due to the large pressure difference of the small terminal 4, which may form a danger. The above-mentioned standard pressure difference between the tank 3 and the small-sized terminal 4 by the pressure recovery assembly does not occur.
In the prior art, the self-pressurization of the vehicle tank body 3 needs to absorb external heat, and the pressure of the small terminal 4 is recovered into the tank body 3 through the pressure recovery assembly, so that the external heat absorption can be reduced, and the number of unloaded vehicles can be increased.
Moreover, the person skilled in the art generally increases the pressure in the tank 3 by means of self-pressurization, which is an increased float pressure. After the vehicle shakes, the vehicle floats and liquefies to form saturated pressure, and the saturated pressure is too high, so that the filling is not facilitated. And as the LNG temperature increases, the saturation pressure also continues to increase. For example, the saturation pressure in the tank 3 is eight kg, the pressure charged into the small terminal 4 must be greater than eight kg. The tank 3 is usually loaded with a maximum pressure of ten kg, so that the tank is not filled or is slowly filled when the pressure is infinitely close to ten kg. Therefore, in order to increase the number of unloaded vehicles, the pressure in the tank 3 needs to be controlled as much as possible, and the number of unloaded vehicles is prevented from being reduced after the self-pressurization is converted into the saturated pressure.
When the saturation pressure of the tank 3 reaches eight kg, the filling cannot be performed without the pressure recovery assembly. However, if the pressure recovery unit is provided, the small terminal 4 can be pumped and pressed, and the filling time is slightly longer than that of normal filling.
The first pressure monitoring device 1 and the second pressure monitoring device 2 are electronic pressure transmitters.
In an embodiment of the present application, the pressure recovery assembly includes two methods, overpressure recovery and boost recovery. The overpressure recovery means that the pressure in the small terminal 4 is larger than the pressure in the tank 3, and the gaseous liquefied natural gas in the small terminal 4 can directly flow back into the tank 3 by directly opening the stop valve 10. After the pressure between the small terminal 4 and the tank 3 is balanced, the small terminal 4 cannot recover the pressure into the tank 3 by itself, so that the gaseous natural gas in the small terminal 4 needs to be continuously compressed and pressurized by the compressor 11 and then is conveyed into the tank 3, and the pressure in the tank 3 is increased. The above-mentioned overpressure recovery is mainly achieved by the first recovery branch 8, and the pressurization recovery is achieved only by the second recovery branch 9.
Wherein, the pressure recovery subassembly includes intake pipe 6, outlet duct 7 and recovery pipeline, and intake pipe 6 passes through recovery pipeline and links to each other with outlet duct 7. The connection point of the air inlet pipe 6 and the small terminal 4 is arranged at the top of the small terminal 4, namely, the air outlet pipe 7 is connected with the top of the small terminal 4. The connection point of the air inlet pipe 6 and the tank body 3 is arranged at the top of the tank body 3, namely the air inlet pipe 6 is connected with the top of the tank body 3. The recovery pipeline comprises a first recovery branch 8 and a second recovery branch 9 which are arranged in parallel, a stop valve 10 is arranged on the first recovery branch 8, a main control valve 12 is arranged on the second recovery branch 9, and a compressor 11 is connected with the control device 5.
The specific overpressure recovery method comprises the following steps: when the second pressure value monitored by the second pressure monitoring device 2 is larger than the first pressure value monitored by the first pressure monitoring device 1, the master control valve 12 and the stop valve 10 are opened, and the gaseous liquefied natural gas in the small terminal 4 sequentially passes through the gas outlet pipe 7, the first recovery branch 8 and the gas inlet pipe 6 to enter the tank body 3 until the pressure in the tank body 3 and the pressure in the small terminal 4 are flat.
In the specific pressurizing recovery method, when the first recovery branch 8 carries out overpressure recovery, the first pressure monitoring device 1 and the second pressure monitoring device 2 continuously monitor the pressure in the small terminal 4 and the tank 3, and when the second pressure value monitored by the second pressure monitoring device 2 is equal to the first pressure value monitored by the first pressure monitoring device 1, the control device 5 turns on the compressor 11. The gaseous liquefied natural gas in the small terminal 4 sequentially passes through the gas outlet pipe 7, the first vaporizer 15, the compressor 11 and the gas inlet pipe 6 to enter the tank body 3, so that the pressure in the tank body 3 is continuously increased while the pressure in the small terminal 4 is reduced, and a positive pressure difference is rapidly formed.
In the specific embodiment of the application, the first recovery branch 8 is provided with a check valve 13, and the air inlet pipe 6 is provided with a one-way valve 14. The check valve 13 is a valve that controls the flow of gas to the tank from a small terminal after the compressor is turned on, and does not circulate. The check valve 14 prevents the pressure in the tank from flowing to the small terminal when the compressor is stopped.
In the specific embodiment of the application, the air outlet pipe 7 is provided with a first vaporizer 15. In the overpressure recovery and the boost recovery of the device, the first vaporizer 15 is used to heat the cryogenic gas of-100 degrees celsius from the small terminal 4, since the compressor 11 requires gaseous liquefied weather gas at normal temperature for operation.
Wherein, the first vaporizer 15 is close to the recovery pipeline and the main control valve 12 is close to the small terminal 4, and the second pressure monitoring device 2 is arranged on the air outlet pipe 7 between the main control valve 12 and the small terminal 4.
In the embodiment of the present application, the tank 3 is connected to a pressurizing device, and if the difference between the first pressure value and the second pressure value is still substantially smaller than the standard pressure difference after the overpressure recovery and the pressurizing recovery, the pressurizing device needs to continuously pressurize the tank 3.
Referring to fig. 3, the supercharging device includes a first supercharging pipe 16, a second supercharging pipe 17 and a second carburetor 18, the first supercharging pipe 16 is connected with the second supercharging pipe 17 through the second carburetor 18, the first supercharging pipe 16 and the second supercharging pipe 17 are both connected with the tank 3, a connection point between the first supercharging pipe 16 and the tank 3 is disposed at the bottom of the tank 3, a connection point between the second supercharging pipe 17 and the tank 3 is disposed at the top of the tank 3, a pneumatic supercharging valve 19 is disposed on the first supercharging pipe 16, and the pneumatic supercharging valve 19 is connected with the control device 5.
In specific control, the first pressure monitoring device 1 monitors the pressure in the tank 3, sends the monitored first pressure value to the control device 5 in real time, the second pressure monitoring device 2 monitors the pressure in the small terminal 4, sends the monitored second pressure value to the control device 5 in real time, the control device 5 compares the difference between the first pressure value and the second pressure value with a standard pressure difference, when the difference between the first pressure value and the second pressure value is smaller than the standard pressure difference, the control device 5 controls the pneumatic booster valve 19 to open, liquid natural gas enters the second vaporizer 18 through the first booster pipe 16 and is vaporized and boosted through the second vaporizer 18, and then reenters the tank 3 through the second booster pipe 17 so as to realize self-pressurization of the tank 3 until the actual pressure difference between the tank 3 and the small terminal 4 is equal to the standard pressure difference. And after the actual pressure difference is equal to the standard pressure difference, the control device 5 controls the pneumatic booster valve 19 to stop boosting and controls the carburetor to stop working at the same time.
The standard differential pressure is arranged in the control device 5, the actual differential pressure between the tank body and the small terminal is controlled by the supercharging device to be equal to the standard differential pressure arranged in the control device, so that the tank body can convey natural gas to the small terminal in a differential pressure mode, excessive heat is prevented from entering the tank body, and therefore accurate control is achieved on the pressure in the tank body, and the number of unloaded vehicles is increased.
In the embodiment of the application, the tank body 3 comprises a main tank body 20 and a sealing head 21, the main tank body 20 is welded with the sealing head 21, one end of the main tank body 20 is provided with an open semi-closed tank body 3, the sealing head 21 is used for sealing the opening of the main tank body 20, and the welded tank body 3 must be ensured to be airtight.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.