CN105179823B - One kind liquefaction shale gas liquefied nitrogen, superconducting direct current cables compound energy Transmission system - Google Patents

Abstract

The invention discloses a liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system, which includes a composite energy generation subsystem, a composite energy transmission subsystem and a composite energy receiving subsystem, wherein the composite energy transmission subsystem will The liquefied shale gas, liquid nitrogen and electric energy generated by the composite energy generation subsystem are sent to the composite energy receiving subsystem; and the liquid nitrogen transmitted through the composite energy transmission subsystem is used to cool the liquefied shale gas in the composite energy transmission subsystem Rock gas transmission pipeline and superconducting DC cable, the liquefied shale gas transmission pipeline is used to transmit liquefied shale gas; the superconducting DC cable is used to transmit the electric energy generated by the composite energy generation subsystem. The invention has higher energy transmission capacity and efficiency than single liquefied shale gas transmission and superconducting direct current cable transmission, and the invention not only does not need to add additional power supply equipment, but also saves the cost of building high-voltage overhead transmission lines.

Description

A Liquefied Shale Gas-Liquid Nitrogen-Superconducting DC Cable Composite Energy Transmission System

technical field

The invention relates to the technical field of oil and gas storage and transportation and the technical field of power transmission, in particular to a liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system.

Background technique

Shale gas is a kind of unconventional natural gas that occurs in shale and mudstone formations and their interlayers in the form of adsorption and dissociation. Compared with traditional petroleum, coal, artificial gas, etc., shale gas has application advantages such as green environmental protection, economic benefits, safety and reliability. Therefore, a wave of shale gas development and utilization has emerged in the global energy and chemical industry.

Generally speaking, shale gas mining areas are far away from large and medium-sized urban areas where gas is concentrated, and it is often necessary to use high pressure to reduce the volume of shale gas by about 250 times for long-distance transportation. However, this compressed shale gas pipeline transportation method has problems such as high pressure safety hazards, low transportation capacity and low efficiency. By using low-temperature refrigeration technology to convert shale gas into liquid liquefied shale gas, the volume of shale gas can be reduced by about 600 times for long-distance transportation. Compared with the former, it has higher transportation capacity and efficiency, and stronger safety and reliability performance. However, with the transportation of liquefied shale gas (-162°C, one atmospheric pressure), traditional means of transportation such as automobiles, trains, and ships carrying liquefied shale gas tanks cannot meet the continuous, fast and flexible supply of shale gas. At the same time, the influence of the heat leakage problem that will exist in the transmission of liquefied shale gas through transmission pipelines, and the liquefied shale gas inside the transmission pipeline is prone to gasification, which will cause excessive pressure in the transmission pipeline and cause safety hazards, so it is not suitable for remote use. Transport of liquefied shale gas over distances.

In recent years, in order to alleviate the increasingly serious energy crisis and environmental protection pressure, in addition to the long-distance transportation of compressed shale gas and liquefied shale gas, shale gas has also been directly used for power generation applications. A large-capacity shale gas power station is directly built in the area where shale gas is mined, and then transmitted to long-distance power users through traditional high-voltage transmission lines. Because shale gas mining areas are often far away from large and medium-sized urban areas with concentrated electricity consumption, traditional high-voltage transmission methods will inevitably bring about the cost of construction and maintenance of high-voltage overhead transmission lines.

Contents of the invention

In order to solve the above technical problems, the present invention provides a liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system.

In order to realize the above-mentioned purpose of the invention, the technical scheme that the present invention adopts is:

A liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system includes a composite energy generation subsystem, a composite energy transmission subsystem and a composite energy receiving subsystem, wherein the composite energy generation subsystem After the shale gas, use part of the gaseous shale gas to generate electricity and convert the rest of the gaseous shale gas into liquefied shale gas, and convert the nitrogen in the air fed into the composite energy generation subsystem into liquid nitrogen ; The composite energy transmission subsystem transports the liquefied shale gas, liquid nitrogen and electric energy produced by the composite energy generation subsystem to the composite energy receiving subsystem;

Moreover, the liquid nitrogen transported through the composite energy transmission subsystem is used to cool the liquefied shale gas transmission pipeline and the superconducting DC cable in the composite energy transmission subsystem, wherein the liquefied shale gas transmission pipeline , used to transmit liquefied shale gas; the superconducting DC cable is used to transmit the electric energy generated by the composite energy generation subsystem.

According to a specific implementation, the composite energy generation subsystem includes shale gas power generation equipment, AC/DC converter station, shale gas liquefaction equipment and nitrogen liquefaction equipment; wherein,

The shale gas power generation equipment uses gaseous shale gas to generate electric energy, and part of the electric energy generated by it supplies power for the shale gas liquefaction equipment and the nitrogen liquefaction equipment, and the rest of the electric energy passes through the AC-DC converter station After being converted into direct current, it is sent to the composite energy receiving subsystem through the superconducting direct current cable;

The liquefied shale gas produced by the shale gas liquefaction equipment is passed into the liquefied shale gas transmission pipeline, the liquid nitrogen produced by the nitrogen liquefaction equipment is passed into the liquid nitrogen transmission pipeline, and the liquefied shale gas is transmitted Both the pipeline and the superconducting DC cable are arranged in the liquid nitrogen transmission pipeline.

According to a specific implementation manner, the superconducting DC cable is arranged coaxially with the liquefied shale gas transmission pipeline, and the superconducting DC cable is located outside the liquefied shale gas transmission pipeline.

According to a specific implementation, several node channels are set on the liquid nitrogen transmission pipeline, and each of the node channels is connected to a liquid replenishment and pressure relief control system, and the liquid nitrogen supply and pressure relief control system includes a liquid nitrogen supply station, a nitrogen recovery station, fluid replenishment and pressure relief control device; among them,

The liquid nitrogen supply station is connected to the node channel through its liquid nitrogen supply pipeline, and the liquid nitrogen supply pipeline is provided with a liquid nitrogen valve;

The nitrogen recovery station is connected to the node pipeline through its nitrogen recovery pipeline, and a nitrogen valve is arranged on the nitrogen recovery pipeline.

According to a specific implementation, the liquid replenishment and pressure relief device includes a control circuit, a liquid level sensor and a pressure sensor; wherein,

The control circuit detects the liquid level of liquid nitrogen in the liquid nitrogen transmission pipeline according to the liquid level sensor, and when the liquid level is lower than the liquid level threshold, the liquid nitrogen valve is opened to make the liquid nitrogen supply station Liquid nitrogen enters the liquid nitrogen transmission pipeline until the liquid level is not lower than the liquid level threshold;

The pressure relief device detects the pressure of nitrogen in the liquid nitrogen transmission pipeline according to the pressure sensor, and when the pressure is higher than the pressure threshold, opens the nitrogen valve so that the nitrogen in the liquid nitrogen transmission pipeline enters the nitrogen gas Recycle bin until the pressure is no higher than the pressure threshold.

According to a specific implementation, the liquid nitrogen transmission pipeline uses liquid nitrogen to cool the power electronic devices inside the liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system through the cooling device, and the The nitrogen recovery station communicates with the cooling device and is used for receiving the nitrogen recovered by the cooling device.

According to a specific implementation manner, the superconducting DC cable is wound by BSCCO high temperature superconducting wire or ReBCO high temperature superconducting wire.

According to a specific implementation manner, the composite energy receiving subsystem includes:

A DC-AC converter station, used to convert the DC power in the superconducting DC cable into AC power;

A substation, configured to receive the alternating current output by the direct current-alternating current converter station and provide it to users;

The liquefied shale gas receiving station is used to receive the liquefied shale gas in the liquefied shale gas transmission pipeline and provide it to users;

The liquid nitrogen receiving station is used to receive the liquid nitrogen transmitted by the composite energy transmission subsystem and provide it to users.

Compared with prior art, the beneficial effect of the present invention is:

The invention utilizes the low-temperature, environment-friendly and safe liquid nitrogen produced by the nitrogen liquefaction equipment to solve the heat leakage problem of the existing liquefied shale gas transmission pipeline, and eliminates the overpressure of the transmission pipeline caused by the gasification phenomenon of the liquefied shale gas. Therefore, it is suitable for long-distance liquefied shale gas transportation. At the same time, the invention combines the technical advantages of shale gas power generation applications, and uses superconducting DC cables with large capacity, approximately zero loss, and low maintenance costs for long-distance power transmission, and uses low-temperature, insulating, environmentally friendly, and safe liquid nitrogen to Maintaining the working environment temperature of superconducting DC cables not only improves the transmission efficiency of electric energy but also saves the cost of construction and maintenance of high-voltage overhead transmission lines. In addition, since the present invention uses the alternating current generated by the shale gas power generation equipment to maintain the continuous power supply of the shale gas liquefaction equipment and the nitrogen liquefaction equipment, there is no need to add additional power supply equipment, and the utilization efficiency of shale gas is improved.

Description of drawings

Fig. 1 is the structural diagram of the composite energy transmission system of liquefied shale gas-liquid nitrogen-superconducting DC cable of the present invention;

Fig. 2 is a structural diagram of the composite energy transmission subsystem of the present invention;

Fig. 3 is a preferred structural diagram of the composite energy transmission subsystem of the present invention;

Fig. 4 is a structural diagram of the fluid replenishment and pressure relief control system of the present invention.

List of reference signs

1: Shale gas power generation equipment 2: Shale gas liquefaction equipment 3: Nitrogen liquefaction equipment 4: AC-DC converter station

5: Liquid nitrogen transmission pipeline 6: Liquefied shale gas transmission pipeline 7: Superconducting DC cable 8: DC-AC converter station

9: Substation 10: Liquefied shale gas receiving station 11: Liquid nitrogen receiving station 12: Energy-saving channel 13: Liquid level sensor 14: Pressure sensor 15: Liquid nitrogen supply station 16: Liquid nitrogen valve 17: Nitrogen recovery station 18: Nitrogen valve

detailed description

The present invention will be further described in detail below in combination with specific embodiments. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

The liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system of the present invention includes a composite energy generation subsystem, a composite energy transmission subsystem and a composite energy receiving subsystem, wherein the composite energy generation subsystem After rock gas, use part of the gaseous shale gas to generate electricity and convert the rest of the gaseous shale gas into liquefied shale gas, and convert the nitrogen in the air fed into the composite energy generation subsystem into liquid nitrogen; composite energy The transmission subsystem transmits the liquefied shale gas, liquid nitrogen and electric energy generated by the composite energy generation subsystem to the composite energy receiving subsystem;

Moreover, the liquid nitrogen transported by the composite energy transmission subsystem is used to cool the liquefied shale gas transmission pipeline 6 and the superconducting DC cable 7 in the composite energy transmission subsystem, wherein the liquefied shale gas transmission pipeline 6 is used for Transmission of liquefied shale gas; superconducting DC cable 7, used to transmit electric energy generated by the composite energy generation subsystem.

The invention uses low-temperature insulating liquid nitrogen to solve the problem of heat leakage in existing liquefied shale gas transmission pipelines, and at the same time uses shale gas to generate electric energy, and uses a superconducting DC cable with large capacity, approximately zero loss, and low maintenance costs. For long-distance transmission, and low-temperature insulating liquid nitrogen is used to provide the working temperature for superconducting DC cables. It not only improves the utilization rate of shale gas, but also improves the transmission efficiency of electric energy and saves the cost of construction and maintenance of high-voltage overhead transmission lines.

Combining the structural diagram of the liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system of the present invention and the structural diagram of the composite energy transmission subsystem of the present invention shown in Fig. 1 and Fig. 2 respectively; wherein, the composite energy generation subsystem It includes shale gas power generation equipment 1, AC/DC converter station 4, shale gas liquefaction equipment 2 and nitrogen liquefaction equipment 3. The composite energy transmission subsystem includes liquid nitrogen transmission pipeline 5 , liquefied shale gas transmission pipeline 6 and superconducting DC cable 7 . The composite energy receiving subsystem includes: DC-AC converter station 8, substation 9, liquefied shale gas receiving station 10 and liquid nitrogen receiving station 11.

Specifically, the shale gas power generation equipment 1 uses gaseous shale gas to generate electric energy, and part of the electric energy generated supplies power for the shale gas liquefaction equipment 2 and the nitrogen liquefaction equipment 3, and the rest of the electric energy is converted by the AC-DC converter station 4 After being converted into DC, it is transported to the DC-AC converter station 8 through the superconducting DC cable 7; the liquefied shale gas produced by the shale gas liquefaction equipment 2 is passed into the liquefied shale gas transmission pipeline 6, and the liquid produced by the nitrogen liquefaction equipment 3 Nitrogen passes in the liquid nitrogen transmission pipeline 5.

In the composite energy transmission subsystem, the liquefied shale gas transmission pipeline 6 and the superconducting DC cable 7 are both arranged in the liquid nitrogen transmission pipeline 5 . The liquefied shale gas transmission pipeline 6 and the superconducting DC cable 7 are refrigerated due to the liquid nitrogen soaked in the liquid nitrogen transmission pipeline 5, which eliminates the gasification phenomenon of the liquefied shale gas in the liquefied shale gas transmission pipeline 6, and Provide a low temperature working environment for the superconducting DC cable 7 .

In the composite energy receiving subsystem, the DC-AC converter station 8 is used to convert the DC power in the superconducting DC cable 7 into AC power. The substation 9 is used to receive the AC power output by the DC-AC converter station 8 and provide it to users. The liquefied shale gas receiving station 10 is used to receive the liquefied shale gas in the liquefied shale gas transmission pipeline 6 and provide it to users. The liquid nitrogen receiving station 11 is used to receive the liquid nitrogen in the liquid nitrogen transmission pipeline 5 and provide it to users.

Combined with the preferred structural diagram of the composite energy transmission subsystem of the present invention shown in Figure 3; wherein, the liquefied shale gas transmission pipeline 6 and the superconducting DC cable 7 are all arranged in the liquid nitrogen transmission pipeline 5, and the superconducting DC cable 7 is coaxial It is arranged outside the liquefied shale gas transmission pipeline 6 . In the liquid nitrogen transmission pipeline 5 with the same diameter, the coaxial superconducting DC cable 7 increases the critical operating current of the cable body on the one hand, and on the other hand increases the contact surface area between the cable and the liquid nitrogen and refrigeration power, thus having higher power transmission capacity, suitable for large-capacity power transmission applications.

The superconducting DC cable 7 adopted in the present invention is wound by BSCCO high temperature superconducting wire or ReBCO high temperature superconducting wire.

In conjunction with the structural diagram of the liquid replenishment and pressure relief control system of the present invention shown in FIG. 4; wherein, a number of node channels 12 are arranged on the liquid nitrogen transmission pipeline 5, and each node channel 12 is correspondingly connected to a liquid replenishment and pressure relief control system. It includes a liquid nitrogen supply station 15, a nitrogen gas recovery station 17, and a fluid replenishment and pressure relief control device.

Among them, the liquid nitrogen supply station 15 is connected with the node channel 12 through the liquid nitrogen supply pipeline, and the liquid nitrogen supply pipeline is provided with a liquid nitrogen valve 16; the nitrogen recovery station 17 is connected with the node pipeline 12 through the nitrogen recovery pipeline, and the nitrogen recovery pipeline is provided with Nitrogen valve 18.

Specifically, the liquid replenishment and pressure relief device includes a control circuit, a liquid level sensor 13 and a pressure sensor 14 . The control circuit detects the liquid level of liquid nitrogen in the liquid nitrogen transmission pipeline 5 according to the liquid level sensor 13, and when the liquid level is lower than the liquid level threshold, that is, when the liquid nitrogen in the liquid nitrogen transmission pipeline 5 is insufficient, the liquid nitrogen valve 16 is opened , the liquid nitrogen in the liquid nitrogen supply station 15 enters the liquid nitrogen transmission pipeline 5 until the liquid level in the liquid nitrogen transmission pipeline 5 is not lower than the liquid level threshold, and the control circuit closes the liquid nitrogen valve 16, thereby ensuring that the liquid nitrogen transmission pipeline The ambient temperature of the liquefied shale gas pipelines and superconducting DC cables in the facility is maintained within a safe range.

The control circuit detects the pressure of nitrogen in the liquid nitrogen transmission pipeline 5 according to the pressure sensor 14. When the pressure is higher than the set threshold, that is, when the gasification phenomenon of nitrogen becomes stronger, the nitrogen valve 18 is opened to make the liquid nitrogen transmission pipeline 5 The nitrogen gas enters the nitrogen recovery station 17 until the pressure in the liquid nitrogen transmission pipeline 5 is not higher than the pressure threshold, and the control circuit closes the nitrogen valve 18, thereby ensuring that the air pressure in the liquid nitrogen transmission pipeline is maintained within a safe range.

The specific embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Those skilled in the art can make various modifications without departing from the spirit and scope of the claims of the application modification or modification.

Claims (3)

1. A liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system, characterized in that it includes a composite energy generation subsystem, a composite energy transmission subsystem and a composite energy receiving subsystem, wherein the composite energy After the gaseous shale gas is fed into the generation subsystem, a part of the gaseous shale gas is used to generate electric energy and the rest of the gaseous shale gas is converted into liquefied shale gas, and the energy is fed into the composite energy generation subsystem. The nitrogen in the air is converted into liquid nitrogen; the composite energy transmission subsystem transports the liquefied shale gas, liquid nitrogen and electric energy produced by the composite energy generation subsystem to the composite energy receiving subsystem; And, the liquid nitrogen transported by the composite energy transmission subsystem is used for cooling the liquefied shale gas transmission pipeline (6) and the superconducting DC cable (7) in the composite energy transmission subsystem, wherein the The liquefied shale gas transmission pipeline (6) is used to transmit the liquefied shale gas; the superconducting DC cable (7) is used to transmit the electric energy generated by the composite energy generation subsystem; Wherein, the composite energy generation subsystem includes shale gas power generation equipment (1), AC-DC converter station (4), shale gas liquefaction equipment (2) and nitrogen liquefaction equipment (3); wherein, The shale gas power generation equipment (1) utilizes gaseous shale gas to generate electric energy, and part of the electric energy generated by it supplies power for the shale gas liquefaction equipment (2) and the nitrogen liquefaction equipment (3), and the rest of the electric energy After being converted into DC by the AC-DC converter station (4), it is transmitted to the composite energy receiving subsystem through the superconducting DC cable (7); The liquefied shale gas produced by the shale gas liquefaction equipment (2) is passed into the liquefied shale gas transmission pipeline (6), and the liquid nitrogen produced by the nitrogen liquefaction equipment (3) is passed into the liquid nitrogen transmission pipeline ( 5), and the liquefied shale gas transmission pipeline (6) and the superconducting DC cable (7) are all arranged in the liquid nitrogen transmission pipeline (5), and the superconducting DC cable (7) and The liquefied shale gas transmission pipeline (6) is arranged coaxially, and the superconducting DC cable (7) is located outside the liquefied shale gas transmission pipeline (6); Several node channels (12) are set on the liquid nitrogen transmission pipeline (5), and each node channel (12) is correspondingly connected to a fluid replenishment and pressure relief control system, and the fluid replenishment and pressure relief control system includes a liquid nitrogen supply station (15 ), nitrogen recovery station (17), liquid replenishment and pressure relief control device; wherein, The liquid nitrogen supply station (15) is connected to the node channel (12) through a liquid nitrogen supply pipeline, and a liquid nitrogen valve (16) is arranged on the liquid nitrogen supply pipeline; The nitrogen recovery station (17) is connected with the node pipeline (12) by a nitrogen recovery pipeline, and the nitrogen recovery pipeline is provided with a nitrogen valve (18); The liquid replenishment and pressure relief device includes a control circuit, a liquid level sensor (13) and a pressure sensor (14); wherein, The control circuit detects the liquid level of liquid nitrogen in the liquid nitrogen transmission pipeline (5) according to the liquid level sensor (13), and when the liquid level is lower than the liquid level threshold, the liquid nitrogen valve (16) is opened , causing the liquid nitrogen in the liquid nitrogen supply station (15) to enter the liquid nitrogen transmission pipeline (5) until the liquid level is not lower than the liquid level threshold; The control circuit detects the pressure of nitrogen in the liquid nitrogen transmission pipeline (5) according to the pressure sensor (14), and when the pressure is higher than the pressure threshold, the nitrogen valve (18) is opened to make the liquid nitrogen The nitrogen in the transmission pipeline (5) enters the nitrogen recovery station (17) until the pressure is not higher than the pressure threshold. 2. The liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system as claimed in claim 1, wherein the superconducting DC cable (7) is made of BSCCO high temperature superconducting wire or ReBCO high temperature superconducting cable Wire wound. 3. The liquefied shale gas-liquid nitrogen-superconducting DC cable composite energy transmission system according to claim 1, wherein the composite energy receiving subsystem comprises: DC-AC converter station (8), used for converting the direct current in the superconducting direct current cable (7) into alternating current; A substation (9), configured to receive the AC power output by the DC-AC converter station (8) and provide it to users; A liquefied shale gas receiving station (10), configured to receive the liquefied shale gas in the liquefied shale gas transmission pipeline (6) and provide it to users; The liquid nitrogen receiving station (11) is used to receive the liquid nitrogen transmitted by the composite energy transmission subsystem and provide it to users.