Comprehensive energy utilization system of natural gas storage

Abstract

The utility model discloses an energy comprehensive utilization system of a natural gas storage, which relates to the field of energy recycling and comprises a natural gas compressor unit, a natural gas differential pressure generator set and an organic Rankine cycle generator set. A first heat exchanger in the organic Rankine cycle generator set is connected in series between a gas outlet of a low-pressure compressor and a gas inlet of a high-pressure compressor in the natural gas compressor set; a second heat exchanger in the organic Rankine cycle generator set is communicated with a differential pressure turbine gas outlet in the natural gas differential pressure generator set; the first heat exchanger is communicated with a feeding port of an ORC turbine in the organic Rankine cycle generator set, and the second heat exchanger is communicated with a discharging port of the ORC turbine. According to the utility model, the energy consumption of the gas storage can be obviously reduced, the complementary energy in the storage and transportation of natural gas can be utilized, and energy conservation and emission reduction are facilitated.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of energy recycling, especially a natural gas storage library's energy comprehensive utilization system. BACKGROUND

[0002] Due to the high gas storage pressure of the natural gas storage library, the natural gas with low pressure needs to be boosted by a compressor before being sent to the storage library for storage, and a multi-stage series compressor set is usually used in this process; the natural gas at the outlet of the low-pressure compressor is usually at a high temperature, which can reach 200 DEG C; the conventional method is to use air or cooling water as the cold source of an inter-stage heat exchanger to reduce the temperature of the natural gas to below 80 DEG C, and then the natural gas is sent to a high-pressure compressor for further compression to reduce the power consumption of the high-pressure compressor, but the heat in the natural gas is not effectively utilized.

[0003] Meanwhile, the pressure of the natural gas changes during the transportation process. For example, the high-pressure natural gas in the pipe network is throttled to reduce the pressure and then enters the production process; the high-pressure natural gas in the gas production well or the gas storage library is throttled to reduce the pressure and then enters the downstream pipeline for transportation. During these pressure changes, a large amount of pressure energy is generated, which is not effectively utilized at present.

[0004] Therefore, a scheme is needed to fully utilize the residual energy to achieve the effect of energy saving and emission reduction. UTILITY MODEL CONTENT

[0005] The utility model aims at the above-mentioned problems, and provides a natural gas storage library's energy comprehensive utilization system, which can significantly reduce the energy consumption of the gas storage library and utilize the residual energy in the natural gas storage and transportation process, thereby helping energy saving and emission reduction.

[0006] The utility model adopts the technical scheme as follows: a natural gas storage library's energy comprehensive utilization system, comprising a natural gas compressor set, a natural gas pressure differential generator set and an organic Rankine cycle generator set; a first heat exchanger in the organic Rankine cycle generator set is connected in series between the gas outlet of a low-pressure compressor in the natural gas compressor set and the gas inlet of a high-pressure compressor; a second heat exchanger in the organic Rankine cycle generator set is connected to the pressure differential turbine gas outlet in the natural gas pressure differential generator set; the first heat exchanger is connected to the feed inlet of an ORC turbine in the organic Rankine cycle generator set, and the second heat exchanger is connected to the discharge outlet of the ORC turbine.

[0007] Further, the organic Rankine cycle generator set further comprises a working medium circulating pump, the inlet of the working medium circulating pump is connected to the high-temperature outlet of the second heat exchanger, and the outlet of the working medium circulating pump is connected to the low-temperature inlet of the first heat exchanger; the low-temperature outlet of the first heat exchanger and the high-temperature inlet of the second heat exchanger are respectively connected to the inlet and the outlet of the ORC turbine.

[0008] Furthermore, in the natural gas compressor unit, the outlet of the low-pressure compressor is connected to the high-temperature inlet of the first heat exchanger; the high-temperature outlet of the first heat exchanger is connected to the inlet of the high-pressure compressor.

[0009] Furthermore, the air inlet of the low-pressure compressor is connected to a low-pressure natural gas source.

[0010] Furthermore, the outlet of the high-pressure compressor is connected to the gas storage tank.

[0011] Furthermore, in the natural gas differential pressure generator set, the outlet of the differential pressure turbine is connected to the low-temperature inlet of the second heat exchanger.

[0012] Furthermore, the low-temperature outlet of the second heat exchanger is connected to a natural gas transmission pipeline.

[0013] Furthermore, the inlet of the differential pressure turbine is connected to a high-pressure natural gas source.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0015] In this invention, the first heat exchanger is shared by a natural gas compressor unit and an organic Rankine cycle generator unit. Within this first heat exchanger, high-temperature natural gas exchanges heat with low-temperature organic working fluid. The natural gas in the natural gas compressor unit is effectively cooled, resulting in a lower temperature, while the low-temperature liquid organic working fluid in the organic Rankine cycle generator unit is heated and evaporated. This achieves the goal of recovering and reusing the heat from the high-temperature natural gas at the compressor outlet. The second heat exchanger is shared by a natural gas differential pressure generator unit and an organic Rankine cycle generator unit. Within this second heat exchanger, low-temperature natural gas exchanges heat with high-temperature organic working fluid. The gaseous organic working fluid in the organic Rankine cycle generator unit is cooled and condensed, while the low-temperature natural gas in the natural gas differential pressure generator unit is effectively heated, resulting in a higher temperature. This achieves the goal of recovering and reusing the cold energy from the low-temperature natural gas at the turbine expander outlet. In short, this system achieves comprehensive and efficient utilization of residual pressure, residual heat, and cold energy, significantly reducing energy consumption in gas storage facilities and utilizing residual energy during natural gas storage and transportation. This is of great significance for promoting energy transformation, protecting the ecological environment, promoting economic development, and improving people's living standards. Attached Figure Description

[0016] This utility model will be described by way of example and with reference to the accompanying drawings, wherein:

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] The diagram is labeled as follows: 1-Natural gas compressor unit; 11-Low-pressure compressor; 12-High-pressure compressor; 2-Natural gas differential pressure generator set; 21-Differential pressure turbine; 3-Organic Rankine cycle generator set; 31-ORC turbine; 32-Second heat exchanger; 33-Working fluid circulation pump; 34-First heat exchanger. Detailed Implementation

[0019] In the description of this specification, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this specification and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this specification.

[0020] Furthermore, the use of terms such as "horizontal" or "vertical" in this specification does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0021] In the description of this specification, it should also be noted that, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “connect” should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components.

[0022] like Figure 1 As shown, a comprehensive energy utilization system for a natural gas storage facility includes a natural gas compressor unit 1, a natural gas differential pressure generator unit 2, and an organic Rankine cycle generator unit 3. A first heat exchanger 34 in the organic Rankine cycle generator unit 3 is connected in series between the outlet of the low-pressure compressor 11 and the inlet of the high-pressure compressor 12 in the natural gas compressor unit 1. A second heat exchanger 32 in the organic Rankine cycle generator unit 3 is connected to the outlet of the differential pressure turbine 21 in the natural gas differential pressure generator unit 2. The first heat exchanger 34 is connected to the inlet of the ORC turbine 31 in the organic Rankine cycle generator unit 3, and the second heat exchanger 32 is connected to the outlet of the ORC turbine 31.

[0023] In the embodiment, the organic Rankine cycle generator set 3 further has a working medium circulating pump 33, an inlet of the working medium circulating pump 33 being communicated with a high-temperature outlet of the second heat exchanger 32, and an outlet of the working medium circulating pump 33 being communicated with a low-temperature inlet of the first heat exchanger 34; a low-temperature outlet of the first heat exchanger 34 and a high-temperature inlet of the second heat exchanger 32 are respectively communicated with an inlet and an outlet of the ORC turbine 31.

[0024] In the embodiment, in the natural gas compressor set 1, an outlet of the low-pressure compressor 11 is communicated with a high-temperature inlet of the first heat exchanger 34; and a high-temperature outlet of the first heat exchanger 34 is communicated with an air inlet of the high-pressure compressor 12.

[0025] In the embodiment, the air inlet of the low-pressure compressor 11 can be communicated with a low-pressure natural gas source, and the low-pressure natural gas source provides low-pressure natural gas.

[0026] In the embodiment, the air outlet of the high-pressure compressor 12 is communicated with a gas storage, and the gas storage is used for storing high-pressure natural gas.

[0027] In the embodiment, in the natural gas differential pressure generator set 2, an air outlet end of the differential pressure turbine 21 is communicated with a low-temperature inlet of the second heat exchanger 32.

[0028] In the embodiment, the low-temperature outlet of the second heat exchanger 32 can be communicated with a natural gas conveying pipe, and the natural gas conveying pipe conveys natural gas.

[0029] In the embodiment, the air inlet end of the differential pressure turbine 21 can be communicated with a high-pressure natural gas source, and the high-pressure natural gas source provides a relatively high-pressure natural gas source.

[0030] In the embodiment, the first heat exchanger 34 and the second heat exchanger 32 can be surface heat exchangers; that is, in the heat exchangers, a low-temperature outlet is communicated with a low-temperature inlet, and a high-temperature outlet is communicated with a high-temperature inlet.

[0031] In the embodiment, in the natural gas compressor set 1 and the organic Rankine cycle generator set 3, after natural gas is compressed by the low-pressure compressor 11, the temperature of the natural gas is greatly increased, and then the natural gas is cooled and reduced in temperature in the first heat exchanger 34; the natural gas cooled and reduced in temperature is then introduced into the high-pressure compressor 12 for further compression, so that the power consumption of the high-pressure compressor 12 can be effectively reduced.

[0032] In the embodiment, in the organic Rankine cycle generator set 3 and the natural gas differential pressure generator set 2, after high-pressure natural gas at normal temperature is expanded and reduced in pressure in the differential pressure turbine 21, the temperature of the natural gas is sharply decreased, and the internal energy is converted into mechanical energy to drive the differential pressure turbine 21 to generate electricity, so that the pressure energy can be recycled; and because the natural gas at too low temperature does not meet the requirements of the downstream process and is not conducive to pipeline transportation, the low-temperature natural gas needs to be heated and increased in temperature in the second heat exchanger 32 by using a heat source.

[0033] In the organic Rankine cycle generator set 3, the low-temperature and high-pressure organic working medium absorbs the heat released by the high-temperature natural gas at the outlet of the low-pressure compressor 11 in the first heat exchanger 34, evaporates into a gaseous state, enters the ORC turbine 31 to expand and generate electricity, and the pressure and temperature of the organic working medium are greatly reduced in the process of expansion work. Then, the low-temperature natural gas at the outlet of the pressure difference turbine 21 cools the low-pressure liquid organic working medium in the second heat exchanger 32, and the working medium circulation pump 33 pressurizes and sends it into the first heat exchanger 34, thereby forming a closed cycle.

[0034] Specific embodiments are as follows.

[0035] The high-pressure and low-temperature liquid organic working medium at the outlet of the working medium circulation pump 33 is generally about 40℃, absorbs heat, evaporates into a gaseous organic working medium, and the temperature reaches 100℃ after entering the first heat exchanger 34. Then, the gaseous organic working medium enters the ORC turbine 31 to expand and do work, the ORC turbine 31 rotates at high speed to generate electricity, and the pressure and temperature of the discharged gaseous organic working medium are 0.25MPa and 60℃, respectively. Then, the gaseous organic working medium is cooled by the low-temperature natural gas from the pressure difference turbine 21 in the second heat exchanger 32, condenses into a liquid state, and returns to the inlet of the working medium circulation pump 33. The liquid organic working medium is pressurized by the working medium circulation pump 33, sent into the first heat exchanger 34 for heat exchange, and forms an ORC closed cycle. The natural gas at the inlet of the pressure difference turbine 21 in the natural gas pressure difference generator set 2 is usually at an ambient temperature of 10-20℃, and after flowing through the pressure difference turbine 21 to expand and reduce pressure, the temperature will drop to below 0℃, which can be used to cool the organic working medium discharged from the ORC turbine 31. After heat exchange in the second heat exchanger 32, the temperature of the natural gas will rise to about 10℃, realizing the recovery and reuse of cold energy.

[0036] The utility model is not limited to the foregoing specific embodiments. The utility model extends to any new feature or any new combination disclosed in the specification, as well as any new method or process step or any new combination disclosed.

Claims

1. A comprehensive energy utilization system for a natural gas storage facility, characterized in that: The natural gas compressor unit (1), the natural gas differential pressure generator unit (2) and the organic Rankine cycle generator unit (3) are included; the first heat exchanger (34) in the organic Rankine cycle generator unit (3) is connected in series between the gas outlet of the low-pressure compressor (11) in the natural gas compressor unit (1) and the gas inlet of the high-pressure compressor (12); the second heat exchanger (32) in the organic Rankine cycle generator unit (3) is communicated with the gas outlet of the differential pressure turbine (21) in the natural gas differential pressure generator unit (2); the first heat exchanger (34) is communicated with the feed inlet of the ORC turbine (31) in the organic Rankine cycle generator unit (3), and the second heat exchanger (32) is communicated with the discharge outlet of the ORC turbine (31).

2. The energy comprehensive utilization system according to claim 1, characterized in that: The organic Rankine cycle generator unit (3) further has a working medium circulating pump (33), the inlet of the working medium circulating pump (33) is communicated with the high-temperature outlet of the second heat exchanger (32), and the outlet of the working medium circulating pump (33) is communicated with the low-temperature inlet of the first heat exchanger (34); the low-temperature outlet of the first heat exchanger (34) and the high-temperature inlet of the second heat exchanger (32) are respectively communicated with the inlet and the outlet of the ORC turbine (31).

3. The energy comprehensive utilization system according to claim 2, characterized in that: In the natural gas compressor unit (1), the gas outlet of the low-pressure compressor (11) is communicated with the high-temperature inlet of the first heat exchanger (34); the high-temperature outlet of the first heat exchanger (34) is communicated with the gas inlet of the high-pressure compressor (12).

4. The energy comprehensive utilization system according to claim 3, characterized in that: The gas inlet of the low-pressure compressor (11) is communicated with the low-pressure natural gas source.

5. The energy comprehensive utilization system according to claim 3, characterized in that: The gas outlet of the high-pressure compressor (12) is communicated with the gas storage.

6. The energy comprehensive utilization system according to claim 2, characterized in that: In the natural gas differential pressure generator unit (2), the gas outlet end of the differential pressure turbine (21) is communicated with the low-temperature inlet of the second heat exchanger (32).

7. The energy comprehensive utilization system according to claim 2, characterized in that: The low-temperature outlet of the second heat exchanger (32) is communicated with the natural gas delivery pipe.

8. The energy comprehensive utilization system according to claim 2, characterized in that: The gas inlet end of the differential pressure turbine (21) is communicated with the high-pressure natural gas source.

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