Gas pressurization method and liquefied gas production method

Abstract

The invention provides a gas pressurization method and a liquefied gas production method, and relates to a low-temperature liquefied gas production technology, and the method comprises the following steps: gasifying liquefied carbon dioxide into power gas; the compressor is driven by power gas to operate; the pressurized gas is compressed through a compressor, pressurized gas is obtained, and the pressure of the pressurized gas is larger than that of the pressurized gas and smaller than that of the power gas; the problems of high energy consumption, high equipment manufacturing difficulty and the like in the gas pressurization process are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-temperature liquefied gas production, and more specifically, relates to a gas pressurization method and a liquefied gas production method. Background Art

[0002] The production of cryogenic liquefied gas, such as natural gas, includes liquefying natural gas to facilitate its storage and transportation. In this regard, the prior art uses a compressor to pressurize natural gas and nitrogen to promote the liquefaction of natural gas. In addition, the pressurized refrigerant gas is processed by an expander to produce low-temperature nitrogen, which is used as a cold source for the cold box to refrigerate the pressurized raw gas. In this process, the electrically driven compressor consumes a lot of energy, resulting in high energy consumption and is not conducive to cost control; and if LNG or liquid nitrogen is used to generate high-pressure gas to drive the compressor, although energy can be saved, the low-temperature performance requirements of the equipment are high, and the equipment is difficult to manufacture. Summary of the invention

[0003] The purpose of the present invention is to provide a gas pressurization method and a liquefied gas production method to address the deficiencies in the prior art, thereby solving the problems of high energy consumption and difficulty in equipment manufacturing during the gas pressurization process.

[0004] In order to achieve the above object, the present invention provides a gas pressurization method, comprising:

[0005] Gasifying liquefied carbon dioxide into power gas;

[0006] Using the power gas to drive the compressor to operate;

[0007] The pressurized gas is compressed by a compressor to obtain a pressurized gas, wherein the pressure of the pressurized gas is greater than the pressure of the pressurized gas and less than the pressure of the power gas.

[0008] Optionally, the liquefied carbon dioxide is heated and gasified into the power gas by a gasifier or by utilizing cold energy.

[0009] Optionally, utilizing the power gas to drive the compressor to operate includes:

[0010] The power gas is input into a steam turbine or an expander, and the steam turbine or the expander drives the compressor to operate;

[0011] Alternatively, the compressor is a pneumatic compressor, which is driven by the power gas to operate.

[0012] Optionally, the pressure of the power gas is 5-25Mpa.

[0013] Optionally, the pressure of the pressurized gas is 2-20 MPa.

[0014] Optionally, after the power gas is used to drive the compressor to operate, the method further includes: compensating the pressure of the power gas after work.

[0015] Optionally, after the power gas is used to drive the compressor to operate, the method further includes: supplementing cooling of the power gas after work to reliquefy the power gas to form reliquefied carbon dioxide.

[0016] Optionally, the reliquefied carbon dioxide is stored and recycled.

[0017] Optionally, the power gas after doing work is supplementally cooled to a temperature below -20°C.

[0018] The present invention also provides a method for producing liquefied gas, comprising:

[0019] Using the above-mentioned gas pressurization method to obtain pressurized gas;

[0020] The pressurized gas is input into a cold box to obtain corresponding liquefied gas.

[0021] The present invention provides a gas pressurization method and a liquefied gas production method, which have the following beneficial effects: the gas pressurization method uses liquefied carbon dioxide as input, gasifies the liquefied carbon dioxide into power gas, and then uses the power gas to drive a compressor to pressurize the pressurized gas to obtain the pressurized gas. The power gas drives the compressor to operate and outputs a depressurized gas, thereby achieving the pressurization of the pressurized gas. In the drive of the compressor, the electric drive in the prior art is replaced, the energy consumption is reduced, and the cost is controlled. In addition, the liquefied carbon dioxide has the characteristics of high boiling point and high liquefaction point. At -20°C, its liquefied pressure is The liquefaction pressure is 1.9696Mpa, at -10℃, it is 2.6487Mpa, at 0℃, it is 3.4851Mpa, at 10℃, it is 4.5022Mpa, at 20℃, it is 5.7291Mpa. The use of liquefied carbon dioxide as a driving raw material can effectively reduce the requirements for the low-temperature resistance of the equipment required for implementing the gas pressurization method, reduce the cost of the equipment and the difficulty of manufacturing. At the same time, after the reduced-pressure gas does work as a power gas, it can be easily converted into liquid after supplementary cooling or supplementary pressure and cooling, and then recycled.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0024] Figure 1 A flow chart of a gas pressurization method according to Embodiment 1 of the present invention is shown.

[0025] Figure 2 A flow chart of a method for producing liquefied gas according to the second embodiment of the present invention is shown.

[0026] Figure 3 A schematic diagram showing the principle of a method for producing liquefied gas according to the second embodiment of the present invention is shown. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0028] Embodiment 1

[0029] like Figure 1 As shown, the present invention provides a gas pressurization method, comprising:

[0030] Gasifying liquefied carbon dioxide into power gas;

[0031] The compressor is driven by power gas;

[0032] The pressurized gas is compressed by a compressor to obtain a pressurized gas, the pressure of which is greater than the pressure of the pressurized gas and less than the pressure of the power gas.

[0033] Specifically, in order to solve the problems of high energy consumption and great difficulty in equipment manufacturing during gas pressurization, the gas pressurization method provided by the present invention uses liquefied carbon dioxide as input, gasifies liquefied carbon dioxide into power gas, and then uses the power gas to drive a compressor to pressurize the pressurized gas to obtain pressurized gas. The power gas drives the compressor to operate and outputs a depressurized gas, thereby achieving the pressurization of the pressurized gas. In the drive of the compressor, the electric drive in the prior art is replaced, energy consumption is reduced, and cost is controlled. In addition, liquefied carbon dioxide has the characteristics of high boiling point and high liquefaction point. At -20°C, its liquefaction point is The pressure is 1.9696Mpa. At -10℃, its liquefaction pressure is 2.6487Mpa, at 0℃, its liquefaction pressure is 3.4851Mpa, at 10℃, its liquefaction pressure is 4.5022Mpa, and at 20℃, its liquefaction pressure is 5.7291Mpa. Using liquefied carbon dioxide as a driving raw material can effectively reduce the requirements for the low-temperature resistance of the equipment required for implementing the gas pressurization method, reduce the cost of the equipment and the difficulty of manufacturing. At the same time, after the depressurized gas does work as a power gas, it can be easily converted into liquid after supplementary cooling or supplementary pressure and cooling, and then recycled.

[0034] Optionally, the liquefied carbon dioxide is heated and gasified into power gas by a gasifier or by utilizing cold energy.

[0035] Specifically, when the liquefied carbon dioxide is gasified, it can be heated and gasified by a gasifier or other cold energy utilization methods, so that it is gasified into a power gas with a first set pressure to drive the compressor to operate and pressurize the pressurized gas.

[0036] Optionally, operating the compressor using motive gas comprises:

[0037] The power gas is input into the steam turbine or the expander, and the compressor is driven by the steam turbine or the expander to operate;

[0038] Alternatively, the compressor adopts a pneumatic compressor, which is driven by power gas to operate.

[0039] Specifically, the power gas can be input into a steam turbine or an expander to drive the impeller of the impeller to rotate, and then the impeller can be used to drive the compressor to pressurize the pressurized gas, or the compressor can be driven by the expander to obtain the pressurized gas with a second set pressure; or a pneumatic compressor can be used to directly drive the pneumatic compressor with the power gas.

[0040] Optionally, the pressure of the power gas is 5-25 MPa.

[0041] Specifically, the first set pressure of the power gas generated by the gasification of liquefied carbon dioxide is 5-25Mpa, which can be input into the steam turbine to drive the impeller to rotate and then drive the compressor to operate, or directly input into the pneumatic compressor to drive it.

[0042] In this embodiment, the power gas passes through a pressure control valve before entering the steam turbine or the pneumatic compressor, and the driving of the compressor by the power gas is ensured by pressure control.

[0043] Optionally, the pressure of the pressurized gas is 2-20 MPa.

[0044] Specifically, the second set pressure of the supercharger after the compressor boosts the gas is 2-20 MPa, but the second set pressure is greater than the original pressure of the boosted gas and less than the first set pressure of the power gas.

[0045] Optionally, after the power gas is used to drive the compressor to operate, the process further includes: compensating the pressure of the power gas after the work is done.

[0046] Specifically, the power gas that has done work can determine whether to pass through the pressure replenishing device for pressure replenishment as needed. The purpose of pressure replenishment is to cooperate with cooling to ensure that the power gas after doing work can be smoothly reliquefied.

[0047] Optionally, after the power gas is used to drive the compressor to operate, the process further includes: supplementing cooling of the power gas after work to reliquefy the power gas to form reliquefied carbon dioxide.

[0048] Specifically, the power gas after doing work can enter the recooling heat exchange device for supplementary cooling and liquefaction, so as to achieve the reliquefaction of the power gas after doing work so as to be circulated and used as a driving raw material.

[0049] Optionally, the reliquefied carbon dioxide is stored and recycled.

[0050] Specifically, a liquefied carbon dioxide storage tank may be provided to store the liquefied carbon dioxide produced by reliquefaction to facilitate its recycling.

[0051] Optionally, the power gas after work is supplementally cooled to a temperature below -20°C.

[0052] Specifically, in order to ensure that the power gas is pressure-regulated and cooled to a temperature exceeding the critical point of temperature and pressure liquefaction through the steam turbine or pneumatic compressor, so that it becomes liquid, a recooling heat exchange device is also provided to ensure that the power gas is cooled to below -20°C to ensure smooth reliquefaction.

[0053] Embodiment 2

[0054] like Figure 2 As shown, the present invention also provides a method for producing liquefied gas, comprising:

[0055] Using the above-mentioned gas pressurization method to obtain pressurized gas;

[0056] The pressurized gas is input into the cold box and the corresponding liquefied gas is obtained.

[0057] Specifically, the liquefied gas production method pressurizes the pressurized gas by the above-mentioned gas pressurization method to obtain pressurized gas, and then inputs the pressurized gas into a cold box to cool it and liquefy it, so that liquefied gas formed by liquefying the pressurized gas can be obtained.

[0058] Furthermore, the liquefied gas production method is suitable for the production of liquefied gases such as liquefied natural gas and liquid nitrogen. It can avoid using electric energy to drive the compressor, and can also avoid using LNG or liquid nitrogen to generate high-pressure gas to drive the compressor, which increases the low-temperature performance requirements of the equipment. In addition, the power gas can be recycled, which can further save energy and costs.

[0059] In this embodiment, if Figure 3 As shown, for the production of LNG, liquefied carbon dioxide is used to produce 7.1MPa high-pressure gas through a gasifier or cold energy utilization equipment, which is used as a power gas. After the pressure is controlled by a pressure control valve, the power gas enters the steam turbine to drive the compressor to operate or directly enters the pneumatic compressor to drive its operation, and the compressor is used to pressurize the raw gas to 5.5MPa; after the power gas does work, the pressure and temperature both drop to the critical point of liquefaction, and then the pressure compensation device and the recooling heat exchange device are used in turn to naturally liquefy it into liquefied carbon dioxide, and store it in a liquefied carbon dioxide storage tank, thereby realizing the recycling of the power gas; and the pressurized raw gas enters the cold box for cooling, so that it is liquefied to form LNG, and is stored in the LNG storage tank. Since liquefied carbon dioxide has the characteristics of high boiling point and high liquefaction point, using liquefied carbon dioxide as a driving raw material can effectively reduce the requirements of the gasifier, cold energy utilization equipment, steam turbine or pneumatic compressor on the low temperature resistance of the material, and reduce the equipment cost and manufacturing difficulty.

[0060] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A gas pressurization method, characterized in that: include: Gasifying liquefied carbon dioxide into power gas; Using the power gas to drive the compressor to operate; The pressurized gas is compressed by a compressor to obtain a pressurized gas, wherein the pressure of the pressurized gas is greater than the pressure of the pressurized gas and less than the pressure of the power gas.

2. The gas pressurization method according to claim 1, characterized in that: The liquefied carbon dioxide is heated and gasified into the power gas by a gasifier or by utilizing cold energy.

3. The gas pressurization method according to claim 1, characterized in that: Using the power gas to drive the compressor to operate includes: The power gas is input into a steam turbine or an expander, and the steam turbine or the expander drives the compressor to operate; Alternatively, the compressor is a pneumatic compressor, which is driven by the power gas to operate.

4. The gas pressurization method according to claim 1, characterized in that: The pressure of the power gas is 5-25Mpa.

5. The gas pressurization method according to claim 1, characterized in that: The pressure of the pressurized gas is 2-20 MPa.

6. The gas pressurization method according to claim 1, characterized in that: After the power gas is used to drive the compressor to operate, the method further includes: compensating the pressure of the power gas after work.

7. The gas pressurization method according to claim 1, characterized in that: After the power gas is used to drive the compressor to operate, the method further includes: supplementing cooling of the power gas after work to reliquefy the power gas to form reliquefied carbon dioxide.

8. The gas pressurization method according to claim 7, characterized in that: The reliquefied carbon dioxide is stored and recycled.

9. The gas pressurization method according to claim 7, characterized in that: The power gas after doing work is supplementally cooled to reduce its temperature to below -20°C.

10. A method for producing liquefied gas, characterized in that: include: Obtaining pressurized gas using the gas pressurization method according to any one of claims 1 to 9; The pressurized gas is input into a cold box to obtain corresponding liquefied gas.

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