Natural gas station excess pressure power generation device

Abstract

The utility model relates to the technical field of natural gas excess pressure power generation, and particularly discloses a natural gas station excess pressure power generation device which comprises a main pipeline, a first-stage natural gas expansion machine and a second-stage natural gas expansion machine are installed on the main pipeline, and one side of the first-stage natural gas expansion machine and one side of the second-stage natural gas expansion machine are both connected with heaters. An inlet stop valve is installed on the other side of the primary natural gas expansion machine, a natural gas inlet is formed in one end of the main pipeline, a natural gas outlet is formed in the other end of the main pipeline, and an auxiliary pipeline is connected between the natural gas inlet and the natural gas outlet. According to the device, the two natural gas expansion machines are arranged on the main pipeline, and the pressure difference of natural gas is fully utilized, so that more electric energy is obtained, and resource waste is avoided; natural gas can quickly pass through a bypass, a natural gas expansion machine or a heater can be overhauled and maintained conveniently, operation is very convenient, and the safety performance is high.

Description

Technical Field

[0001] The utility model relates to the technical field of natural gas surplus pressure power generation, in particular to a natural gas station surplus pressure power generation device. Background Art

[0002] The Chinese utility model patent, with the authorization announcement number CN 212803350 U, discloses a natural gas station field pressure regulating residual pressure power generation device, including: an inlet preheater, an inlet shut-off valve, a natural gas expansion generator, an outlet heater, a bypass pressure regulating valve, a quick-opening bypass shut-off valve, and a quick-opening bypass regulating valve. The quick-opening bypass shut-off valve and the quick-opening bypass regulating valve provided in the residual pressure generator set are arranged in parallel with the bypass pressure regulating valve of the natural gas station field. Under normal working conditions, the bypass pressure regulating valve is closed, and the pressure regulating residual pressure power generation device realizes the pressure regulating and residual pressure power generation functions.

[0003] However, this technology has the following defects: the device cannot make full use of the natural gas pressure difference to obtain more electricity, and a large amount of pressure difference is not fully utilized, resulting in a great waste of resources. Moreover, when the preheater fails, the whole unit needs to be shut down for maintenance, which is very inconvenient to operate and has poor flexibility. Therefore, a natural gas station residual pressure power generation device is provided. Utility Model Content

[0004] The purpose of the utility model is to provide a natural gas station residual pressure power generation device in view of the defects of the prior art, so as to solve the problems raised by the above-mentioned background technology.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a natural gas station residual pressure power generation device, comprising a main line, on which a first-stage natural gas expander and a second-stage natural gas expander are installed, one side of the first-stage natural gas expander and the second-stage natural gas expander are both connected to a heater, and an inlet shut-off valve is installed on the other side of the first-stage natural gas expander, one end of the main line is provided with a natural gas inlet, and the other end of the main line is provided with a natural gas outlet, a secondary pipeline is connected between the natural gas inlet and the natural gas outlet, and a bypass shut-off valve and a bypass pressure regulating valve are installed on the secondary pipeline.

[0006] As a preferred technical solution of the utility model, a circulating water low-grade heat source is installed on the heater.

[0007] As a preferred technical solution of the utility model, the first-stage natural gas expander and the second-stage natural gas expander are both connected to a gearbox, and the gearbox is connected to a generator.

[0008] As a preferred technical solution of the utility model, the rotating shaft of the generator is connected to the gear in the gearbox, and the gear in the gearbox is connected to the closed impeller rotating shafts in the first-stage natural gas expander and the second-stage natural gas expander through a high-speed coupling.

[0009] As a preferred technical solution of the utility model, the secondary pipeline is connected to the main pipeline through a tee.

[0010] As a preferred technical solution of the utility model, the heaters are respectively arranged at the gas outlets of the first-stage natural gas expander and the second-stage natural gas expander.

[0011] Compared with the prior art, the beneficial effects of the utility model are: the device is equipped with two natural gas expanders on the main pipeline, which makes full use of the natural gas pressure difference to obtain more electricity and avoid waste of resources. Moreover, compared with the prior art, when the residual pressure power generation device or heater of the device fails, the natural gas can be quickly passed through the bypass to facilitate the inspection and maintenance of the natural gas expander or heater. The operation is very convenient and the safety performance is strong.

[0012] The device does not consume natural gas, has a large power generation capacity and can comprehensively utilize the cold energy generated by natural gas pressure reduction. It has a low investment, occupies a small area, has high economic benefits, and can ensure long-term stable operation of the device. It is particularly suitable for stations with large pressure differences and large natural gas flows such as natural gas pipeline terminals and pressure regulating stations.

[0013] It not only achieves the purpose of pressure regulation, but also utilizes the excess pressure of natural gas to generate a large amount of electricity, and comprehensively utilizes the cold energy generated by the pressure reduction to improve energy utilization.

[0014] The residual pressure power generation device at the natural gas station can effectively recycle and utilize wasted pressure energy, use the pressure difference to generate electricity to meet the company's own electricity needs, and the remaining electricity will be connected to the power grid. In the process of power generation, cold energy will be generated, which can be supplied to surrounding companies, thereby improving energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the utility model.

[0016] In the figure: inlet shut-off valve 1, first-stage natural gas expander 2, heater 3, second-stage natural gas expander 4, bypass shut-off valve 5, bypass pressure regulating valve 6, gearbox 7, generator 8, secondary pipeline 9, circulating water low-grade heat source 10, main pipeline 11. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0018] Example: See Figure 1The utility model provides a technical solution: a natural gas station residual pressure power generation device, including a main line 11, a first-stage natural gas expander 2 and a second-stage natural gas expander 4 are installed on the main line 11, a heater 3 is connected to one side of the first-stage natural gas expander 2 and the second-stage natural gas expander 4, an inlet cut-off valve 1 is installed on the other side of the first-stage natural gas expander 2, a natural gas inlet is provided at one end of the main line 11, a natural gas outlet is provided at the other end of the main line 11, a secondary pipeline 9 is connected between the natural gas inlet and the natural gas outlet, and a bypass cut-off valve 5 and a bypass pressure regulating valve 6 are installed on the secondary pipeline 9.

[0019] A circulating water low-grade heat source 10 is installed on the heater 3 .

[0020] The first-stage natural gas expander 2 and the second-stage natural gas expander 4 are both connected to a gearbox 7 , and the gearbox 7 is connected to a generator 8 .

[0021] The rotating shaft of the generator 8 is connected to the gears in the gearbox 7 through a low-speed coupling, and the gears in the gearbox 7 are connected to the closed impeller rotating shafts in the first-stage natural gas expander 2 and the second-stage natural gas expander 4 through a high-speed coupling.

[0022] The secondary pipeline 9 is connected to the main pipeline 11 through a tee.

[0023] The heaters 3 are respectively arranged at the gas outlets of the first-stage natural gas expander 2 and the second-stage natural gas expander 4 .

[0024] Working principle: A natural gas station residual pressure power generation device. After the normal temperature and high pressure natural gas enters the pressure regulating residual pressure power generation device through the station pipeline and the inlet cut-off valve 1, the natural gas enters the first-stage natural gas expander 2 tangentially from the variable nozzle. A part of the natural gas expansion is completed in the nozzle, and a part of it is entropically expanded on the impeller in the first-stage natural gas expander 2 to achieve energy conversion, complete work, and drive the closed impeller to rotate at high speed, and then the low-pressure and low-temperature natural gas is discharged from the diffuser; the rotation of the impeller drives the high-speed coupling, and the speed is adjusted through the gearbox 7, and then the gearbox 7 drives the generator to generate electricity through the low-speed coupling.

[0025] After the low-pressure and low-temperature natural gas leaves the first-stage natural gas expander 2, it enters the heater 3 to exchange heat with low-grade heat sources such as circulating water refrigerant. The low-pressure and low-temperature natural gas is heated and then discharged from the device.

[0026] The heated natural gas enters the secondary expansion generator again to make full use of the natural gas pressure difference and obtain more electric energy. Then it enters the heater 3 to prevent the natural gas temperature out of the device from being lower than the allowable temperature of the pipeline material.

[0027] When the residual pressure power generation device fails, the pressure regulation of the station is set in parallel with the pressure regulating residual pressure power generation device. The bypass cut-off valve 5 and the bypass pressure regulating valve 6 are used to close the inlet cut-off valve 1 of the expander in an emergency when the residual pressure power generation device fails, and the bypass cut-off valve 5 is quickly opened to allow natural gas to pass through the bypass, ensuring that the pressure fluctuation of the device does not exceed 0.3Mpa / min, ensuring the normal operation of the upstream device and stable operating pressure.

[0028] The device does not consume natural gas, has a large power generation capacity and can comprehensively utilize the cold energy generated by natural gas pressure reduction. It has a low investment, occupies a small area, has high economic benefits, and can ensure long-term stable operation of the device. It is particularly suitable for stations with large pressure differences and large natural gas flows such as natural gas pipeline terminals and pressure regulating stations.

[0029] It not only achieves the purpose of pressure regulation, but also utilizes the excess pressure of natural gas to generate a large amount of electricity, and comprehensively utilizes the cold energy generated by the pressure reduction to improve energy utilization.

[0030] The residual pressure power generation device at the natural gas station can effectively recycle and utilize wasted pressure energy, use the pressure difference to generate electricity to meet the company's own electricity needs, and the remaining electricity will be connected to the power grid. In the process of power generation, cold energy will be generated, which can be supplied to surrounding companies, thereby improving energy utilization.

[0031] The above embodiments only express the implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model.

Claims

1. A natural gas station residual pressure power generation device, comprising a main line (11), characterized in that: The main pipeline (11) is provided with a first-stage natural gas expander (2) and a second-stage natural gas expander (4), one side of each of the first-stage natural gas expander (2) and the second-stage natural gas expander (4) is connected to a heater (3), the other side of the first-stage natural gas expander (2) is provided with an inlet shut-off valve (1), one end of the main pipeline (11) is provided with a natural gas inlet, the other end of the main pipeline (11) is provided with a natural gas outlet, a secondary pipeline (9) is connected between the natural gas inlet and the natural gas outlet, and a bypass shut-off valve (5) and a bypass pressure regulating valve (6) are installed on the secondary pipeline (9).

2. A natural gas station residual pressure power generation device according to claim 1, characterized in that: The heater (3) is provided with a circulating water low-grade heat source (10).

3. A natural gas station residual pressure power generation device according to claim 1, characterized in that: The first-stage natural gas expander (2) and the second-stage natural gas expander (4) are both connected to a gearbox (7), and the gearbox (7) is connected to a generator (8).

4. A natural gas station residual pressure power generation device according to claim 3, characterized in that: The rotating shaft of the generator (8) is connected to the gear in the gearbox (7), and the gear in the gearbox (7) is connected to the closed impeller rotating shafts in the first-stage natural gas expander (2) and the second-stage natural gas expander (4) through a high-speed coupling.

5. A natural gas station residual pressure power generation device according to claim 1, characterized in that: The secondary pipeline (9) is connected to the main pipeline (11) via a tee.

6. A natural gas station residual pressure power generation device according to claim 1, characterized in that: The heaters (3) are respectively arranged at the gas outlets of the first-stage natural gas expander (2) and the second-stage natural gas expander (4).

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