Flare gas recovery power generation device

Abstract

The utility model discloses a flare gas recovery power generation device which comprises a flare gas liquid separation tank, a Stirling generator set, a flare head and a controller, a flare gas outlet of the flare gas liquid separation tank is connected with the input end of a flare gas main pipeline, and the flare gas main pipeline is connected with a plurality of branch pipelines. The tail ends of the branch pipelines are connected with the torch head and one or more Stirling generator sets respectively, the Stirling generator sets are connected in parallel, first pressure regulating valves are arranged on the branch pipelines connected with the Stirling generator sets respectively, and safety regulating parts are arranged on the branch pipelines connected with the torch head. A pressure transmitter is arranged on the flare gas main pipeline, and the first pressure adjusting valve, the safety adjusting part and the pressure transmitter are in communication connection with the controller. The device is reliable in safety performance, small in occupied area, low in weight, low in cost and flexible in power utilization mode.

Description

Technical Field

[0001] The utility model relates to the technical field of flare gas recovery, in particular to a flare gas recovery power generation device. Background Art

[0002] The main components of flare gas are gaseous alkanes and hydrogen. The main sources of flare gas are crude oil associated gas, low-pressure flash gas, equipment sealing gas, chemical plant tail gas, etc. The recycling technology of flare gas has a certain role in promoting carbon reduction, environmental protection, energy conservation and emission reduction. There are two ways to recycle flare gas: one is to recycle the flare gas into the natural gas production and processing system and transport it through the gas pipeline. The other is to recover the energy after the flare gas is burned.

[0003] There are two difficulties in the recovery and utilization of flare gas: 1. It is difficult to recover and transport the flare gas. Oil fields that mainly produce crude oil do not have natural gas production and processing technology and natural gas transmission pipelines, and do not have the conditions to transport the flare gas. 2. It is difficult to use flare gas for natural gas engines to generate electricity. Flare gas contains a large amount of free water, as well as sulfides and nitrides. These components will form acidic compounds that corrode the cylinders of natural gas engines. Therefore, the flare gas needs a series of devices for filtration before it can be used in natural gas generator sets. The filtration of flare gas requires the use of a large number of equipment, which has the disadvantages of occupying a large area and high cost.

[0004] Although flare gas contains a large amount of impurities, these impurities do not affect the flare gas as fuel for external combustion engines. There are two types of external combustion engines, one is a steam turbine and the other is a Stirling engine. There is a technical solution in the prior art to apply the waste heat of flare gas to steam turbine power generation. However, the steam engine occupies too much space and has a complex structure. It is suitable for large power generation equipment, but not for flare gas combustion power generation equipment. The Stirling engine was once designed for flare gas power generation equipment. Reference patent application number 201811195523.0 is a flare gas recovery and processing system for power generation and its recovery and processing method. This patent uses water seal tanks, pressure swing adsorption towers, gas cabinets and other devices, which has the disadvantage of occupying a large area. Utility Model Content

[0005] The purpose of the present application is to provide a flare gas recovery power generation device to solve the problems raised in the above background technology.

[0006] To achieve the above objectives, this application provides the following technical solutions:

[0007] A flare gas recovery power generation device comprises a flare liquid separator, a Stirling generator set, a flare head and a controller, wherein the flare gas outlet of the flare liquid separator is connected to the input end of a flare gas main pipeline, a plurality of branch pipelines are connected to the flare gas main pipeline, the ends of the branch pipelines are respectively connected to the flare head and one or more Stirling generator sets, a plurality of Stirling generator sets are connected in parallel, a first pressure regulating valve is respectively provided on the branch pipelines connected to the Stirling generator set, a safety regulating part is provided on the branch pipeline connected to the flare head, a pressure transmitter is provided on the flare gas main pipeline, and the first pressure regulating valve, the safety regulating part and the pressure transmitter are respectively communicatively connected to the controller.

[0008] Furthermore, the safety regulating unit includes a second pressure regulating valve, a pneumatic quick-opening valve and a bursting disc connected in parallel, and the second pressure regulating valve is communicatively connected to the controller.

[0009] Furthermore, the pressure transmitter is arranged on the flare gas main pipeline close to the flare liquid separation tank and the Stirling generator set.

[0010] Furthermore, an engine exhaust pipe is provided on the exhaust gas emission outlet of the Stirling generator set.

[0011] Furthermore, when the air pressure value is greater than 70 kPaG, the pneumatic quick-opening valve opens automatically.

[0012] Furthermore, when the air pressure value is greater than 100 kPaG, the bursting disc automatically ruptures.

[0013] In summary, the technical effects and advantages of the utility model are as follows: reliable safety performance. Since the Stirling engine is an external combustion engine, changes in the gas composition of the flare gas and fluctuations in the gas supply will not affect the normal operation of the Stirling engine; the device does not need to filter the moisture and acidic oxides in the flare gas before it can be delivered to the highly integrated Stirling generator set for combustion and power generation, thus eliminating a series of filtering equipment, which makes the device have the advantages of small footprint and low weight; the device directly delivers the flare gas output from the flare separator tank to the Stirling generator set for power generation, and has the characteristics of high integration and streamlined equipment, thereby reducing construction and maintenance costs; the device generates electricity by recycling the flare gas, thereby reducing the fuel consumption of the original generator and saving the fuel cost of the original generator set; the power consumption method is flexible, and the electricity generated by the Stirling generator set does not need to be incorporated into the main power grid, but can be independently supplied to unimportant electrical equipment, such as air-conditioning units, light sets, water heaters, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 This is a schematic diagram of the structure of the flare gas recovery power generation device in the first embodiment of the utility model;

[0016] Figure 2 It is a structural schematic diagram of the flare gas recovery power generation device in the second embodiment of the utility model.

[0017] Among them, 1. Torch separator tank; 2. Stirling generator set; 3. Torch head; 4. First pressure regulating valve; 5. Pressure transmitter; 6. Second pressure regulating valve; 7. Pneumatic quick opening valve; 8. Bursting disc; 9. Engine exhaust pipe. DETAILED DESCRIPTION

[0018] The following specific description refers to the accompanying drawings, which show embodiments in which the present invention can be implemented. It should be noted that the various embodiments described in the present invention are not necessarily mutually exclusive, so the technical features of different embodiments can be combined to form new embodiments. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments, and the implementation methods of the present invention may have any deformation or modification without departing from the principles. In the case where the technical features of different embodiments are combined together without causing contradictions, the application of dependent claims is made herein.

[0019] In the description of the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0020] The working gas in the Stirling generator can be hydrogen, helium or air, etc., depending on the design requirements and application scenarios. The working gas alternately expands and compresses during the cycle to achieve energy conversion. The Stirling generator requires a high-temperature heat source and a low-temperature cold source. The heat source provides high-temperature heat to expand the working gas; the cold source provides low temperature to compress the working gas. The heat source and cold source can be external heating and cooling systems, or natural heat sources such as solar energy and geothermal energy. There are two pistons in the Stirling generator, one on the heat source side and the other on the cold source side. The piston and the cylinder form a closed working chamber, and the working gas expands and compresses under the push of the piston. The Stirling generator drives the generator rotor to rotate through the reciprocating motion of the piston, converting mechanical energy into electrical energy. The generator usually adopts the principle of electromagnetic induction, generates current through the interaction between the coil and the magnetic field, and then generates electrical energy output. In the prior art, there is a method of recovering the flare gas after filtering and treating it as fuel for the turbine generator set. However, most offshore platforms currently do not have turbine generator sets, so it is necessary to design a new flare gas recovery power generation device. The flare gas recovery and utilization device suitable for offshore oil fields needs to have the characteristic of small footprint and complete the energy recovery of flare gas safely and efficiently under the condition of small footprint.

[0021] The flare gas recovery power generation device of the utility model has the characteristics of small footprint. The flare gas pipeline includes a flare gas main pipeline and a branch pipeline. In the utility model, "normal pressure value" refers to the air pressure value in the flare gas pipeline when the equipment is working normally. For example, the air pressure value is 10-50kPaG. "Warning pressure value" refers to an abnormal increase in the air pressure value in the flare gas pipeline. Under this section of air pressure value, it will not cause damage to the equipment or dangerous accidents. For example, the air pressure value is 70-100kPaG. "Dangerous pressure value" refers to an abnormal increase in the air pressure value in the flare gas pipeline. Under this section of air pressure value, the equipment may be damaged or a dangerous accident may occur. For example, the air pressure value exceeds 100kPaG.

[0022] Example 1

[0023] This embodiment proposes a flare gas recovery power generation device with a small footprint, such as Figure 1As shown, it includes a flare liquid separator 1, a Stirling generator set 2, a flare head 3 and a controller. The flare liquid separator 1 is used to separate the flare gas from gas and liquid. The flare gas outlet of the flare liquid separator 1 is connected to the input end of the flare gas main pipeline, and the flare gas main pipeline is connected to multiple branch pipelines. The ends of the branch pipelines are respectively connected to the flare head 3 and one or more Stirling generator sets 2. Multiple Stirling generator sets 2 are connected in parallel. The branch pipelines connected to the Stirling generator set 2 are respectively provided with a first pressure regulating valve 4, which is used to adjust the air pressure in the branch pipeline. The branch pipeline connected to the flare head 3 is provided with a safety regulating part, which is used to ensure the safety of the entire device. The flare gas main pipeline is provided with a pressure transmitter 5, which is used to monitor the air pressure in the pipeline in real time. The first pressure regulating valve 4, the safety regulating part and the pressure transmitter 5 are respectively connected to the controller for communication.

[0024] Specifically, the safety regulating part includes a second pressure regulating valve 6, a pneumatic quick opening valve 7 and a bursting disc 8 connected in parallel, and the second pressure regulating valve 6 is communicatively connected to the controller. Further, the pressure transmitter 5 is arranged on the flare gas main pipeline close to the flare liquid separation tank 1 and the Stirling generator set 2.

[0025] Specifically, an engine exhaust pipe 9 is provided on the exhaust gas outlet of the Stirling generator set 2 .

[0026] Optionally, when the air pressure value is greater than 70 kPaG, the pneumatic quick-opening valve 7 automatically opens. When the air pressure value is greater than 100 kPaG, the bursting disc 8 automatically ruptures.

[0027] The working process of this embodiment:

[0028] The pressure of the flare gas recovery power generation device is monitored by the pressure transmitter 5 and transmitted to the controller; if the pressure is normal, the flare gas is delivered to the Stirling generator set 2 for power generation; if the pressure exceeds the normal pressure standard but does not reach the warning pressure value, the first pressure regulating valve 4 is closed, the Stirling generator set 2 is closed, and the second pressure regulating valve 6 is opened, so that the gas separated in the flare liquid separator 1 is passed through the flare gas pipeline equipped with the second pressure regulating valve 6 to the flare head 3 for combustion and discharge; if the pressure reaches the warning pressure value but does not reach the dangerous pressure value, the first pressure regulating valve 4 is closed, the Stirling generator is closed Group 2, and open the second pressure regulating valve 6, the pneumatic quick-opening valve 7 automatically opens, so that the gas separated in the flare separator 1 can be discharged through the flare gas pipeline equipped with the second pressure regulating valve 6 and the pneumatic quick-opening valve 7 to the flare head 3 for combustion; if the system pressure exceeds the dangerous pressure value, close the first pressure regulating valve 4, close the Stirling generator set 2, and open the second pressure regulating valve 6, the pneumatic quick-opening valve 7 automatically opens, and the bursting disc 8 automatically ruptures, so that the gas separated in the flare separator 1 can be discharged through the flare gas pipeline equipped with the second pressure regulating valve 6, the pneumatic quick-opening valve 7 and the bursting disc 8 to the flare head 3 for combustion.

[0029] Example 2

[0030] like Figure 2 As shown, the difference between this embodiment and embodiment 1 is that the ends of the branch pipelines are respectively connected to multiple parallel Stirling generator sets 2, and this arrangement is to enable the flare gas to be fully recovered for power generation. The rest is the same as embodiment 1. The power cables, cooling water injection pipes, cooling water discharge pipes and other installation and operation methods required for the Stirling generators adopt the existing technology, and this technical solution will not be repeated.

[0031] The utility model has reliable safety performance. Since the Stirling engine is an external combustion engine, even if the flare gas contains a large amount of water and acidic compounds, it can still be used as fuel for the Stirling generator set. Changes in the gas composition of the flare gas and fluctuations in the gas supply will not affect the normal operation of the Stirling engine. Small footprint and low weight. The flare gas recovery power generation device of the utility model does not need to filter the water and acidic oxides in the flare gas, and can be delivered to the highly integrated Stirling generator set for combustion and power generation, thereby eliminating a series of filtering equipment, so that the device of the utility model has the advantages of relatively small footprint and low weight. On the offshore oil platform, the main consideration for installing the flare gas recovery and utilization device is the need for a small footprint. Low cost. Since the utility model eliminates the dehydration treatment process and membrane separation treatment process for the flare gas, the flare gas output from the flare liquid separation tank is directly delivered to the Stirling generator set for power generation. Therefore, the flare gas recovery power generation device of the utility model has the characteristics of high integration and streamlined equipment, thereby reducing construction costs and maintenance costs. The device of the utility model generates electricity by recycling flare gas, thereby reducing the fuel consumption of the original generator. The fuel cost of the original generator set is saved. The electricity use method is flexible. The electricity generated by the Stirling generator set can be independently supplied to unimportant electrical equipment, such as air conditioning units, electric light units, water heaters, etc., instead of being incorporated into the main power grid. The reason for such a setting is that it is difficult to connect the electricity generated by the Stirling generator set to the grid.

[0032] Although the preferred implementation cases of the utility model have been described above in conjunction with the accompanying drawings, the utility model is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the utility model, ordinary technicians in this field can also make many forms of specific changes without departing from the scope of protection of the utility model and the claims, which all fall within the scope of protection of the utility model.

Claims

1. A flare gas recovery power generation device, characterized in that: It includes a flare separator tank, a Stirling generator set, a flare head and a controller. The flare gas outlet of the flare separator tank is connected to the input end of the flare gas main pipeline. The flare gas main pipeline is connected to a plurality of branch pipelines. The ends of the branch pipelines are respectively connected to the flare head and one or more Stirling generator sets. The plurality of Stirling generator sets are connected in parallel. The branch pipelines connected to the Stirling generator sets are respectively provided with a first pressure regulating valve, the branch pipeline connected to the flare head is provided with a safety regulating part, the flare gas main pipeline is provided with a pressure transmitter, and the first pressure regulating valve, the safety regulating part and the pressure transmitter are respectively communicated with the controller.

2. The flare gas recovery power generation device according to claim 1, characterized in that: The safety regulating part comprises a second pressure regulating valve, a pneumatic quick-opening valve and a bursting disc connected in parallel, and the second pressure regulating valve is communicatively connected with the controller.

3. The flare gas recovery power generation device according to claim 1, characterized in that: The pressure transmitter is arranged on the flare gas main pipeline close to the flare liquid separation tank and the Stirling generator set.

4. The flare gas recovery power generation device according to claim 1, characterized in that: An engine exhaust pipe is arranged on the tail gas discharge outlet of the Stirling generator set.

5. The flare gas recovery power generation device according to claim 2, characterized in that: When the air pressure value is greater than 70 kPaG, the pneumatic quick-opening valve opens automatically.

6. The flare gas recovery power generation device according to claim 2, characterized in that: When the air pressure value is greater than 100 kPaG, the bursting disc automatically ruptures.

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