Novel LNG (Liquefied Natural Gas) gasifier of circulating fluidized bed

Abstract

The invention discloses a novel circulating fluidized bed LNG vaporizer which comprises a lower drainage device, a nozzle is embedded in the lower drainage device, the lower drainage device is communicated with a lower bent pipe, the lower drainage device is connected with the lower bent pipe in a welded mode, the lower bent pipe is communicated with a secondary flow pipe, and the two ends of a plurality of long ascending pipes are fixedly connected to an upper pipe plate and a lower pipe plate. The upper end of the end socket is communicated with an upper bent pipe, the conical end socket is connected with the upper bent pipe in a welded mode, the upper bent pipe is communicated with an upper box, the top end of the upper box is communicated with a hot fluid outlet, and the end, away from the upper box, of the downcomer is communicated with a lower drainage device. In the device, solid particles enter the lower drainage device from the bottom of the descending pipe, are brought into the lower bent pipe through negative pressure after passing through the nozzle, enter the lower box and enter the ascending pipe at a high speed through the ascending distribution short pipe, the function that the pipe wall is rubbed without freezing is achieved, and the solid particles are decelerated after reaching the upper box and return to the descending pipe through gravity for the next cycle. LNG enters the shell side from an inlet at the baffle plate, and flows out from an outlet at the top of the shell side after being gasified.

Description

Technical Field

[0001] The invention relates to the technical field of LNG gasifiers, in particular to a novel circulating fluidized bed LNG gasifier. Background Art

[0002] At present, circulating fluidized bed heat exchangers usually use welding to fix heat exchange tubes and tube sheets. When using welding methods to process and manufacture circulating fluidized bed heat exchangers, it is necessary to reserve sufficient operating space for welding heat exchange tubes and tube sheets. The increase in operating space will lead to a decrease in the number of heat exchange tubes. The reduction in the number of heat exchange tubes will reduce the heat exchange efficiency of the vaporizer. The use of welding to fix heat exchange tubes and tube sheets will also make it difficult to disassemble the entire equipment, making it inconvenient to adjust or inspect. In addition, the temperature difference between LNG and hot fluid is too large, and the traditional structure of the heat exchanger is prone to ice blockage. At present, there is no such compact circulating fluidized bed LNG vaporizer.

[0003] Therefore, a new circulating fluidized bed LNG gasifier is proposed to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a new circulating fluidized bed LNG gasifier to solve the problems existing in the above-mentioned prior art, increase the number of heat exchange tubes and avoid ice blockage.

[0005] To achieve the above object, the present invention provides the following solution: The present invention provides a novel circulating fluidized bed LNG gasifier, comprising:

[0006] A lower flow guider, a nozzle is embedded in the lower flow guider, the lower flow guider is connected to a lower bend pipe, the lower flow guider is welded to the lower bend pipe, the lower bend pipe is connected to a secondary flow pipe, the lower bend pipe is connected to a lower fluidizing box at one end away from the lower flow guider, a plurality of rising distribution short pipes are arranged in the lower fluidizing box, the rising distribution short pipes correspond to long rising pipes, the rising distribution short pipes are fixedly connected to the distribution plate, the two ends of the plurality of long rising pipes are fixedly connected to the upper tube plate and the lower tube plate, a shell is fixedly connected between the upper tube plate and the lower tube plate, a plurality of LNG inlets are provided on the shell, a plurality of baffles are fixedly connected in the shell, the baffles are not completely in contact with the shell, and a plurality of baffles are provided on the baffles A through hole is provided, wherein the short tube of the ascending distribution pipe passes through the through hole, the size of the through hole is larger than the size of the short tube of the ascending distribution pipe, the LNG inlet is located above the baffle, a natural gas outlet is provided on the top of the shell, a flange is fixedly connected to the lower tube box, the flange is fixedly connected to the lower tube plate by bolts, the end of the long ascending pipe away from the short tube of the ascending distribution pipe is connected with a conical head, the long ascending pipe is connected to the head by a flange, the upper end of the head is connected with an upper bend pipe, the conical head is welded to the upper bend pipe, the upper bend pipe is connected with an upper box, the top end of the upper box is connected with a hot fluid outlet, the bottom end of the upper box is connected with a down pipe, and the end of the down pipe away from the upper box is connected with the lower guide device.

[0007] The present invention discloses the following technical effects: In the present invention, LNG enters the shell side of the vaporizer from the inlet uniformly distributed on the shell, absorbs heat and vaporizes on and between the baffles, and flows out from the outlet at the top of the shell side. The heating fluid enters from the secondary flow pipe and the nozzle, enters the lower bend pipe after the intersection, and then flows upward to enter the lower fluidization box, passes through the ascending distribution short pipe and the long ascending pipe in sequence, completes the vaporization in this process, and then flows through the upper head, enters the upper bend pipe, and then flows horizontally and enters the upper box. In this device, solid particles enter the guide tube from the bottom of the downcomer, are brought into the lower bend pipe by the negative pressure behind the nozzle, enter the lower box, and enter the ascending pipe at high speed through the ascending distribution short pipe, realizing the function of friction without ice on the tube wall. After the solid particles reach the upper box, they sink due to the reduced speed, enter the downcomer, and return to the lower guide tube under the action of gravity and the negative pressure of the guide tube to carry out the next cycle. LNG enters the shell side of the vaporizer through several uniformly distributed inlets on the vaporizer shell, exchanges heat with the high-temperature fluid and vaporizes, and flows out from the outlet of the vaporizer shell side. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0009] Figure 1 This is a schematic diagram of the structure of a novel circulating fluidized bed LNG gasifier of the present invention;

[0010] Figure 2 This is a schematic diagram of the connection between the long tube of the rising distribution pipe, the short tube of the rising distribution pipe and the distribution plate of the present invention;

[0011] Figure 3 This is a schematic diagram of the lower elbow structure of the present invention;

[0012] Among them, 1. nozzle; 2. lower nozzle; 3. secondary flow pipe; 4. lower bend pipe; 5. lower pipe box; 6. short pipe of rising distribution pipe; 7. distribution plate; 8. long pipe of rising distribution pipe; 9. conical head; 10. upper bend pipe; 11. overflow pipe; 12. upper box; 13. downcomer; 14. LNG inlet; 15. baffle; 16. natural gas outlet. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Reference Figure 1-3 The present invention provides a novel circulating fluidized bed LNG gasifier, comprising:

[0016] A lower flow guide 2, a nozzle 1 is embedded in the lower flow guide 2, the lower flow guide 2 is connected to a lower bend pipe 4, the lower flow guide 2 is welded to the lower bend pipe 4, the lower bend pipe 4 is connected to a secondary flow pipe 3, the lower bend pipe 4 is connected to a lower fluidizing box 5 at one end away from the lower flow guide 2, a plurality of rising distribution short pipes 6 are arranged in the lower fluidizing box 5, the rising distribution short pipes 6 correspond to long rising pipes 8, the rising distribution short pipes 6 are fixedly connected to the distribution plate 7, the two ends of the plurality of long rising pipes 8 are fixedly connected to the upper tube sheet and the lower tube sheet, a shell is fixedly connected between the upper tube sheet and the lower tube sheet, a plurality of LNG inlets 14 are provided on the shell, a plurality of baffles are fixedly connected in the shell, the baffles are not completely in contact with the shell, and a plurality of through holes are provided on the baffles The rising distribution pipe short tube 6 passes through the through hole, the size of the through hole is larger than the size of the rising distribution pipe short tube 6, the LNG inlet 14 is located above the baffle 15, and a natural gas outlet 16 is opened on the top of the shell. A flange is fixedly connected to the lower tube box 5, and the flange is fixedly connected to the lower tube plate by bolts. The long rising pipe 8 is connected to the head 9 at one end away from the rising distribution pipe short tube 6. The long rising pipe 8 is connected to the head 9 through a flange, and the upper end of the head 9 is connected to an upper bend pipe 10, which is welded to the upper bend pipe 10. The upper bend pipe 10 is connected to an upper box 12, and the top of the upper box 12 is connected to a hot fluid outlet 11, and the bottom of the upper box 12 is connected to a downcomer 13, and the end of the downcomer 13 away from the upper box 12 is connected to the lower guide device 2.

[0017] In the device, the upper bend 10 is connected to the upper box 12 by flanges, the upper box 12 is connected to the downcomer 13 by flanges, and the downcomer 13 is connected to the lower guide device 2 by flanges; the heating fluid enters from the nozzle 1, combines with the solid particles to form a multiphase flow and passes through the lower guide device 2, and another heating fluid enters from the secondary flow pipe 3. The heating fluid after intersection enters the lower bend 4 and then flows upward into the lower tube box 5, and passes through the ascending distribution short pipe 6 and the long ascending pipe 8 in sequence. In this process, the LNG in the shell is heat-exchanged and vaporized with the hot fluid in the tube bundle, and then flows upward along the guide notch of the baffle 15, and flows out from the gaseous natural gas outlet 16 at the top of the shell, and the solid phase particles then flow through the upper head, enter the upper bend, turn to flow horizontally and enter the upper box, and fall into the downcomer 13 after the speed is reduced, forming a cycle.

[0018] In this device, solid particles enter the lower guide tube from the bottom of the downcomer, are carried into the lower bend by the negative pressure behind the nozzle, enter the lower box, and enter the riser at high speed through the ascending distribution short tube, realizing the function of friction against the tube wall without ice formation. After the solid particles reach the upper box, the speed decreases and they return to the downcomer by gravity for the next cycle. LNG enters the shell side of the vaporizer through several evenly distributed inlets on the vaporizer shell, exchanges heat with the high-temperature fluid to vaporize, and flows out from the shell side outlet of the vaporizer.

[0019] In the present invention:

[0020] (1) The expansion and welding method is used to connect the long riser tube to the upper and lower tube sheets, and the flange is used to connect the lower tube sheet of the fixed distribution plate and the flange of the lower fluidizing box, which effectively eliminates the defect of reducing the number of heat exchange tubes due to the reserved welding distance, so that the heat exchange efficiency is guaranteed;

[0021] (2) The ratio of the length L of the straight section of the lower elbow to its bending radius R is designed to be no less than 5:1, which effectively eliminates the defects of insufficient channel distribution or insufficient speed to form circulation after the multiphase flow turns due to the straight section of the lower elbow being too short or too long.

[0022] (3) A special form of fluidized bed heat exchanger is used as the vaporizer for LNG, which is a domestic first.

[0023] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0024] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A novel circulating fluidized bed LNG gasifier, characterized in that: include: A lower flow guide (2), wherein a nozzle (1) is embedded in the lower flow guide (2), the lower flow guide (2) is connected to a lower curved pipe (4), the lower flow guide (2) is welded to the lower curved pipe (4), the lower curved pipe (4) is connected to a secondary flow pipe (3), the lower curved pipe (4) is connected to a lower fluidizing box (5) at one end away from the lower flow guide (2), and a plurality of rising distribution short pipes (6) are arranged in the lower fluidizing box (5), and the rising distribution short pipes (6) are connected to the lower curved pipe (4). There should be a long riser (8), the short riser pipe (6) is fixedly connected to the distribution plate (7), the two ends of the long riser pipes (8) are fixedly connected to the upper tube plate and the lower tube plate, a shell is fixedly connected between the upper tube plate and the lower tube plate, the shell is provided with a plurality of LNG inlets (14), the shell is fixedly connected with a plurality of baffles, the baffles are not completely in contact with the shell, the baffles are provided with a plurality of through holes, the short riser pipe (6) passes through the through holes, the size of the through holes is larger than the size of the short riser pipe (6), the LNG inlet (14) is located above the baffle (15), a natural gas outlet (16) is provided on the top of the shell, a flange is fixedly connected to the lower tube box (5), the flange is fixedly connected to the lower tube plate by bolts, the end of the long riser pipe (8) away from the short riser pipe (6) is connected with a conical head (9), the long riser pipe (8) The sealing head (9) is connected to the sealing head (9) via a flange, the upper end of the sealing head (9) is connected to an upper curved pipe (10), the conical sealing head (9) is welded to the upper curved pipe (10), the upper curved pipe (10) is connected to an upper box (12), the top end of the upper box (12) is connected to a hot fluid outlet (11), the bottom end of the upper box (12) is connected to a downcomer (13), and the end of the downcomer (13) away from the upper box (12) is connected to the lower guide device (2).

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