A staged LNG vaporizer structure

Abstract

The application provides a hierarchical LNG gasifier structure, which is mainly applied to an LNG organic Rankine cycle power generation process, and is mainly composed of a primary gasifier and a secondary gasifier. According to different states of LNG and organic working medium in the gasifier, the structures of the two-stage gasifiers are designed respectively. The primary gasifier is composed of a shell and an internal sleeve, the inner tube of the internal sleeve adopts a spraying pipeline, and the outer tube of the sleeve adopts a petal-shaped pipeline. The secondary gasifier is composed of a shell and an internal pipeline, and annular fins are uniformly arranged on the inner surface of the shell and the outer surface of the pipeline. The gasifier has the advantages that different heat exchange sides are strengthened according to different heat exchange stages of LNG and organic working medium, the gasification efficiency of the gasifier is improved through the mode, and the gasifier has the characteristics of simple structure and high heat exchange efficiency. The structure of the LNG gasifier improves the heat exchange efficiency and saves the floor area.

Description

Technical Field

[0001] This invention relates to the technical field of LNG vaporizers, and specifically to a novel staged LNG vaporizer with high-efficiency heat exchange. Background Technology

[0002] With social development and progress, my country's demand for natural gas energy is constantly increasing, and the country's natural gas supply system is becoming increasingly sophisticated. The growing demand for liquefied natural gas (LNG) has also spurred research into the recovery and utilization of LNG cold energy, with organic Rankine cycle power generation being a highly efficient recovery method. LNG vaporizers, which heat and vaporize LNG to specified conditions during the cycle, are widely used in LNG receiving terminals and are indispensable equipment in the LNG vaporization process. Existing LNG vaporizers are mostly ambient air vaporizers and submerged combustion vaporizers. Ambient air vaporizers use air as a heat source, resulting in a low heat transfer coefficient. To meet the vaporization needs of large-volume LNG flows, a large heat exchange area is required, leading to a large vaporizer footprint and higher LNG vaporization costs. Submerged combustion vaporizers use fuel gas as a heat source, resulting in higher operating costs, lower safety, and fluctuations in the supply of combustion air and fuel gas, which can severely impact the normal operation of the vaporizer. Summary of the Invention

[0003] To address the problems of the aforementioned heat exchangers, this invention provides a novel staged LNG vaporizer with a compact structure and high heat exchange efficiency, which can greatly improve the vaporization efficiency of LNG.

[0004] The technical solution of this invention is as follows: it includes a primary vaporizer and a secondary vaporizer. The primary vaporizer structure of this invention consists of an outer shell and an inner double-layered tube. The inner pipe of the inner double-layered tube is a spray pipe with an inner diameter of 10mm, and several spray holes are evenly distributed on the pipe surface. The outer pipe of the double-layered tube is a petal-shaped pipe, where each petal-shaped pipe is an arc with a diameter of 15mm and an angle of 45°. One end of the double-layered tube has an open inner pipe and a closed outer pipe, serving as the pipe inlet; the other end has an open outer pipe and a closed inner pipe, serving as the pipe outlet.

[0005] The two-stage vaporizer structure of this invention consists of an outer shell and an internal pipe, the inner diameter of which is 10 mm. Several annular ribs are evenly and intersectingly arranged on the inner surface of the vaporizer shell and the outer surface of the internal pipe.

[0006] The first-stage vaporizer and the second-stage vaporizer of the present invention have LNG inlets and outlets at the left and right ends of the shell, respectively; and organic working fluid inlets and outlets at the upper and lower sides of the shell, respectively.

[0007] Compared with existing LNG vaporizers for organic Rankine cycles, this invention has the following advantages:

[0008] This invention employs a staged gasification technology. Since the hot and cold fluids are in different states at different stages of heat exchange, and the heat exchanger has a weaker heat exchange side, a two-stage gasifier is specifically designed to enhance the weaker heat exchange side at different stages. This two-stage gasification approach improves heat exchange efficiency and reduces heat exchanger costs. Attached Figure Description

[0009] Figure 1 A schematic diagram of the structure of the first-stage vaporizer of the present invention is shown.

[0010] Figure 2 A schematic diagram of the structure of the two-stage vaporizer of the present invention is shown.

[0011] Figure 3 A cross-sectional view of the first-stage vaporizer of the present invention is shown.

[0012] Figure 4 A schematic diagram of the internal piping structure of the first-stage vaporizer of the present invention is shown.

[0013] Figure 5 A schematic diagram of the internal piping structure of the secondary vaporizer of the present invention is shown.

[0014] In the diagram, 1. LNG inlet of the first-stage vaporizer; 2. LNG outlet of the first-stage vaporizer; 3. Organic working fluid outlet of the first-stage vaporizer; 4. Organic working fluid inlet / outlet of the first-stage vaporizer; 5. LNG spray pipeline; 6. LNG pipeline of the first-stage vaporizer; 7. Organic working fluid pipeline of the first-stage vaporizer; 8. LNG pipeline of the second-stage vaporizer; 9. Organic working fluid pipeline of the second-stage vaporizer; 10. Ring rib; 11. LNG inlet of the second-stage vaporizer; 12. LNG outlet of the second-stage vaporizer; 13. Organic working fluid outlet of the second-stage vaporizer; 14. Organic working fluid inlet / outlet of the second-stage vaporizer; 15. Inner rib of the organic working fluid pipeline of the second-stage vaporizer; 16. Outer rib of the LNG pipeline of the second-stage vaporizer. Detailed Implementation

[0015] To provide a clearer understanding of the technical features, objectives, and effects of this invention, the invention will be further described below in conjunction with the accompanying drawings.

[0016] like Figure 1 , Figure 2 As shown, the present invention provides a staged LNG vaporizer structure, including a first-stage LNG vaporizer and a second-stage LNG vaporizer.

[0017] The specific workflow of the staged LNG vaporizer designed in this scheme is as follows:

[0018] LNG enters the inner double-layered casing of the first-stage vaporizer through inlet 1 at one end. Under fluid pressure, LNG is ejected from the spray holes of the inner spray pipe 5 within the casing and enters the outer LNG pipe 6 of the double-layered casing. Organic working fluid vapor enters the shell 7 of the first-stage heat exchanger through the organic working fluid inlet 4 above the first-stage vaporizer. The LNG in the LNG pipe exchanges heat with the organic working fluid in the shell of the first-stage heat exchanger through the casing wall. After heat exchange in the first-stage vaporizer, the LNG changes from a liquid state to natural gas wet vapor, and the organic working fluid vapor changes back to a liquid state.

[0019] After heat exchange in the primary vaporizer, the wet natural gas vapor flows through a pipeline into the LNG pipeline 8 inside the secondary vaporizer. The organic working fluid flows through a pipeline into the shell 9 of the secondary vaporizer. The wet natural gas vapor in the internal pipeline exchanges heat with the organic working fluid in the shell. The fins distributed on the outer surface of the pipeline and the inner surface of the shell increase the heat exchange area and enhance the disturbance of the organic working fluid in the shell. After heat exchange in the secondary heat exchanger, the LNG becomes ambient temperature gaseous natural gas, and the organic working fluid vapor becomes saturated liquid.

[0020] The specific embodiments of the present invention have been described in detail above, but the content is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention.

Claims

1. A staged LNG vaporizer structure comprising a primary vaporizer structure and a secondary vaporizer structure connected by a conduit, characterized in that, The primary gasifier structure is composed of an outer shell and an inner double-layer sleeve; the inner pipeline of the inner double-layer sleeve adopts a spray pipeline, the inner diameter of which is 10 mm, and a plurality of spray holes are uniformly arranged on the surface of the pipeline; the outer pipeline of the double-layer sleeve adopts a pipeline with a petal-shaped cross section, wherein each petal-shaped pipeline adopts a circular arc with a diameter of 15 mm and an angle of 45°; one end of the double-layer sleeve is open at the inner pipeline and closed at the outer pipeline, serving as the inlet of the pipeline; the other end is open at the outer pipeline and closed at the inner pipeline, serving as the outlet of the pipeline. The secondary gasifier structure is composed of an outer shell and an inner pipeline, and a plurality of ring ribs are uniformly and crossly arranged on the inner surface of the shell and the outer surface of the inner pipeline.

2. A staged LNG vaporizer structure according to claim 1, wherein, The primary gasifier and the secondary gasifier are respectively provided with an LNG inlet and an outlet at the left and right ends of the shell, and respectively provided with an organic working medium inlet and an outlet at the upper and lower sides of the shell.

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