Natural gas liquefaction waste heat recovery device

Abstract

The utility model relates to the technical field of natural gas liquefaction, and discloses a natural gas liquefaction waste heat recovery device, in the natural gas liquefaction waste heat recovery device, a second cavity area is divided into three layers through a vertical plate and a transverse plate in a replacement box body, so that high-temperature natural gas forms three groups of independent spaces for one-to-one heat replacement, the heat exchange space range is reduced, and the heat transfer efficiency is improved. The cooling pipe mechanism is matched with the pump, circulation and flow of a cooling medium are accurately controlled, and heat exchange stability is guaranteed. The heat replacement pipe mechanism is composed of spiral high-temperature-resistant heat exchange pipes, natural gas is evenly distributed in cooperation with the distribution block mechanism, and the heat replacement process is optimized. The protective net component protects the cooling pipe mechanism and is convenient to check and maintain. The device effectively solves the problems that a traditional waste heat recovery device is low in heat exchange efficiency, wastes energy and the like, the energy utilization rate in the natural gas liquefaction process is increased, the operation cost is reduced, stable operation of equipment is guaranteed, and good practicability and economical efficiency are achieved.

Description

Technical Field

[0001] This utility model relates to the field of natural gas liquefaction technology, and more specifically to a natural gas liquefaction waste heat recovery device. Background Technology

[0002] In the field of natural gas liquefaction, waste heat recovery is a key step in improving energy efficiency and reducing production costs. With the continuous growth in natural gas demand and the increasing awareness of energy conservation, efficient waste heat recovery devices are receiving more and more attention. During the natural gas liquefaction process, high-temperature natural gas undergoes compression and cooling processes, generating a large amount of waste heat. If this waste heat is not effectively recovered, it not only wastes energy but also increases the additional cooling load, thereby raising production costs.

[0003] Traditional natural gas liquefaction waste heat recovery units typically employ a relatively simple heat exchange structure. A common approach is to install straight pipes within a large cavity as heat exchange channels, recovering waste heat through heat exchange between the cooling medium and the natural gas. However, this traditional structure has the following specific problems: due to the large heat exchange space and lack of effective partitioning, the heat distribution is relatively dispersed as the high-temperature natural gas flows within the cavity, making it difficult to achieve centralized and efficient heat exchange. Insufficient contact between the cooling medium and the natural gas results in low heat exchange efficiency, failing to maximize waste heat recovery, leading to energy waste and increased energy costs in the liquefaction process. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the existing technology and provide a waste heat recovery device for natural gas liquefaction. This device optimizes the traditional waste heat recovery device for natural gas liquefaction, which suffers from problems such as large heat exchange space, lack of effective zoning, and simple heat exchange structure, resulting in dispersed heat distribution of high-temperature natural gas and insufficient contact between the cooling medium and natural gas, thus causing low waste heat recovery efficiency, serious energy waste, and increased operating costs.

[0005] The technical solution adopted by this utility model to solve the above-mentioned technical problems is:

[0006] A waste heat recovery device for natural gas liquefaction includes a displacement chamber. Both ends of the displacement chamber are connected to an intake pipe for air intake and an exhaust pipe for air exhaust. An internal heat displacement pipe mechanism is installed inside the displacement chamber. This mechanism is connected to the intake and exhaust pipes via a diverter mechanism, which diverts the heated gas input through the intake pipe to displace heat and then returns it to the exhaust pipe for discharge. Vertical plates at both ends of the displacement chamber divide the interior into two first cavity areas and a second cavity area between the two first cavity areas. The interior of the second cavity area is further divided into three layers from top to bottom by two sets of horizontal plates and two sets of vertical plates. A cooling pipe mechanism connecting the three layers of the corresponding second cavity area is installed on the outside of the displacement chamber.

[0007] Preferably, each of the diversion block mechanisms includes a diversion block body disposed inside the second cavity region. The ends of the two diversion block bodies that are far apart from each other are provided with diversion channels. The diversion channels are divided into three groups and are respectively connected to the interior of the corresponding second cavity region. The heat exchange tube mechanism inside the second cavity region corresponds one-to-one with the diversion channels at adjacent ends of the two diversion tubes.

[0008] Preferably, each of the diversion blocks is a trapezoidal and high-temperature resistant metal block.

[0009] Preferably, the cooling pipe mechanism includes a pump installed outside the replacement box. The pump's input end and output end are respectively connected to cooling pipe one and cooling pipe two. The ends of cooling pipe one and cooling pipe two that are far apart from each other are connected to the inner sides of the corresponding second cavity area. The ends of cooling pipe one and cooling pipe two that are close to each other are detachably connected to the pipes at the corresponding ends of the pump through flanges.

[0010] Preferably, a protective net component is installed on the outside of the replacement box. The protective net component includes a protective net cover. The cooling pipe mechanism located outside the replacement box is covered inside the protective net cover. The upper part of the protective net cover is movably connected with movable doors corresponding to the front and rear of the pump.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] This natural gas liquefaction waste heat recovery device divides the second cavity into three layers using vertical and horizontal plates inside the replacement tank. This allows the high-temperature natural gas to be divided into three independent spaces for one-to-one heat exchange, relatively reducing the spatial range of heat exchange and making heat transfer more concentrated and efficient. The external cooling pipe mechanism works in conjunction with a pump. Cooling pipe one and cooling pipe two are connected to both sides of the replacement tank, respectively. The pump drives the circulation of the cooling medium, allowing precise control of the flow rate and direction. This ensures full contact and heat exchange between the cooling medium and the natural gas within the heat exchange pipe mechanism, significantly improving the efficiency and uniformity of heat exchange. This effectively enhances the waste heat recovery effect, enabling the device to better meet the heat recovery requirements during natural gas liquefaction, reducing energy consumption, lowering operating costs, and enhancing the product's market competitiveness.

[0013] This natural gas liquefaction waste heat recovery unit utilizes a unique heat exchange tube mechanism and a diversion block mechanism within the replacement tank. The heat exchange tube mechanism consists of multiple spirally arranged high-temperature resistant heat exchange tubes. This spiral arrangement increases the residence time of natural gas within the tubes and the contact area with the cooling medium. Combined with the diversion block mechanism's uniform distribution of natural gas, this further optimizes the heat exchange process and improves heat exchange efficiency. Simultaneously, the diversion block body is constructed with a specific trapezoidal shape and high-temperature resistant metal material, ensuring stable operation under high-temperature and high-pressure environments. Reliable sealing methods are employed between the diversion block and other components, guaranteeing the unit's airtightness and safety. Furthermore, the protective mesh component provides protection for the cooling tube mechanism, and the movable door facilitates inspection and maintenance of the pump and connecting components, reducing the risk of equipment damage or malfunction due to external factors. This ensures long-term stable operation of the unit, improves its overall practicality and reliability, and reduces production interruptions and maintenance costs caused by equipment failures. Attached Figure Description

[0014] Figure 1 This is a three-dimensional schematic diagram of an embodiment of a natural gas liquefaction waste heat recovery device.

[0015] Figure 2 This is a half-section diagram of the internal structure of a natural gas liquefaction waste heat recovery unit.

[0016] Figure 3 A schematic diagram of the tangent portion of a natural gas liquefaction waste heat recovery unit;

[0017] Figure 4 Right view of a natural gas liquefaction waste heat recovery unit;

[0018] Figure 5 This is a bottom view of the natural gas liquefaction waste heat recovery device in Example 2;

[0019] Figure 6 This is a top view of the natural gas liquefaction waste heat recovery device in Example 2.

[0020] Legend:

[0021] 1. Replacement housing; 101. Inlet pipe; 102. Exhaust pipe; 2. Vertical plate; 201. First cavity area; 202. Second cavity area; 203. Horizontal plate; 3. Cooling pipe one; 301. Flange; 302. Cooling pipe two; 4. Pump; 5. Diverter block body; 501. Diverter channel; 6. Replacement pipe body; 7. Protective mesh cover; 701. Movable door. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments. However, those skilled in the art should understand that the detailed description given here with reference to the accompanying drawings is for better explanation. The structure of the present invention may exceed the limited embodiments described herein. Some equivalent alternatives or common means will not be described in detail here, but they still fall within the protection scope of this application.

[0023] Figures 1-6 This is the preferred embodiment of the present invention, which is described below in conjunction with the appendix. Figures 1-6 The present invention will be further described below.

[0024] Example 1, see Figure 1 - Figure 4 As shown, the natural gas liquefaction waste heat recovery device mainly consists of a replacement tank 1. The two ends of the replacement tank 1 are respectively connected to an inlet pipe 101 for inlet gas and an exhaust pipe 102 for outlet gas. Specifically, the inlet pipe 101 is used to introduce external heated natural gas into the replacement tank 1, while the exhaust pipe 102 discharges the natural gas after heat replacement from the device.

[0025] In this embodiment, vertical plates 2 are provided at both ends of the interior of the replacement chamber 1. The vertical plates 2 divide the interior of the replacement chamber 1 into two sets of first cavity areas 201 and a second cavity area 202 located between the two sets of first cavity areas 201. Inside the second cavity area 202, it is divided into three layers from top to bottom by two sets of horizontal plates 203 adjacent to the two sets of vertical plates 2. Specifically, this partitioned structure allows the high-temperature natural gas carrying heat entering the replacement chamber 1 to be divided into three independent spaces by the vertical plates 2, the second cavity area 202, and the horizontal plates 203 during the transportation process, achieving one-to-one heat exchange and thus effectively improving heat exchange efficiency.

[0026] In this embodiment, a heat exchange tube mechanism is provided inside the replacement chamber 1. The heat exchange tube mechanism is connected to the intake pipe 101 and the exhaust pipe 102 through a diversion block mechanism. Each diversion block mechanism includes a diversion block body 5 disposed inside the second cavity region 202. Diversion channels 501 are opened at the ends of the two sets of diversion block bodies 5 that are far apart from each other. The diversion channels 501 are divided into three groups and are respectively connected to the interior of the corresponding second cavity region 202. The heat exchange tube mechanism inside the second cavity region 202 corresponds one-to-one with the diversion channels 501 at adjacent ends of the two sets of diversion tubes. Specifically, the hot gas input from the intake pipe 101 first enters the diversion block mechanism, is diverted through the diversion channels 501 into the heat exchange tube mechanism, undergoes heat exchange with the cooling medium in the heat exchange tube mechanism, and then flows back and merges to be discharged from the exhaust pipe 102. The main body 5 of the diverter block is trapezoidal and made of high-temperature resistant metal blocks (such as stainless steel or nickel-based alloys, with a high temperature resistance range of 800℃-1200℃, an upper base length of 30mm-50mm, a lower base length of 50mm-80mm, and a height of 40mm-60mm). It is connected to the intake pipe 101, the exhaust pipe 102, and the heat exchange pipe mechanism through welding or sealing connection components to ensure that there is no leakage when the gas is transmitted between the components.

[0027] The heat exchange tube mechanism consists of multiple high-temperature resistant heat exchange tubes arranged in a spiral pattern. These tubes are made of a special thermally conductive alloy material with a wall thickness between 3mm and 5mm and an inner diameter between 15mm and 25mm. This spiral arrangement increases the residence time of natural gas within the tubes and the contact area with the cooling medium, thereby improving heat exchange efficiency. Both ends of the heat exchange tubes are tightly connected to the distribution channels 501 of the distribution block body 5. The connections are sealed and secured with gaskets and fastening nuts to prevent gas leakage. Within the second cavity region 202, the heat exchange tubes are evenly distributed in three layers. The number of heat exchange tubes in each layer is rationally configured according to the space size and heat exchange requirements, generally 10-20 heat exchange tubes per layer. The spiral directions of adjacent layers are opposite, allowing the cooling medium to form more complex flow channels during flow, further enhancing the heat exchange effect.

[0028] In this embodiment, a cooling pipe mechanism is provided on the outside of the replacement box 1, connecting the three layers corresponding to the second cavity area 202. The cooling pipe mechanism includes a pump 4 installed outside the replacement box 1. The input end and output end of the pump 4 are respectively connected to cooling pipe 3 (input end side) and cooling pipe 302 (output end side). The ends of cooling pipe 3 and cooling pipe 302 that are far apart from each other are connected to the two sides inside the corresponding second cavity area 202. The ends of cooling pipe 3 and cooling pipe 302 that are close to each other are detachably connected to the pipes at the corresponding ends of the pump 4 through flange 301. Specifically, pump 4 delivers the cooling medium (such as water or ethylene glycol aqueous solution, with a specific heat capacity between 2.5-4.2 kJ / (kg・℃) and a boiling point between 100℃-197℃) through cooling pipe 302 to the second cavity 202 inside the displacement chamber 1. When the high-temperature natural gas from the outside enters the second cavity 202 inside the displacement chamber 1, it passes through the interior of the displacement pipe body 6. The cooling medium inside the second cavity 202 is wrapped around the exterior of the displacement pipe body 6 in the three layers of the second cavity 202, thus replacing the heat inside the displacement pipe body 6.

[0029] Example 2, based on Example 1, such as Figure 5 -like Figure 6 As shown, to protect the outer recovery pipe assembly of the replacement chamber 1, a protective net component is installed on the outer side of the replacement chamber 1 in this embodiment. The protective net component includes a protective net cover 7, and the cooling pipe mechanism located outside the replacement chamber 1 is covered inside the protective net cover 7. The upper part of the protective net cover 7 is movably connected to a movable door 701 corresponding to the front and rear of the pump 4. Specifically, the protective net cover 7 is made of metal with a mesh size of 5mm-10mm. By opening the movable door 701, the connection status between the pump 4 and the first cooling pipe 3, flange 301 and the second cooling pipe 302 can be checked at any time to see if there is any loosening. By setting the protective net component on the outer side of the replacement chamber 1, the cooling pipe mechanism on the outer side of the replacement chamber 1 can be protected, preventing unauthorized personnel from accidentally touching the cooling pipe mechanism.

[0030] The working principle and usage process of this utility model are as follows: During operation, high-temperature natural gas enters through the inlet pipe 101, first flowing into the diversion block mechanism, and then being evenly diverted through the diversion channel 501 before entering the heat exchange tube mechanism. Simultaneously, the pump 4 starts, drawing in the cooling medium from the first cooling pipe 3. After being pressurized by the pump 4, the medium is transported through the second cooling pipe 302 to the second cavity area 202 of the replacement chamber 1. The cooling medium envelops the heat exchange tube mechanism within the three-layer space of the second cavity area 202. As the high-temperature natural gas flows within the heat exchange tube mechanism, its heat is transferred to the surrounding cooling medium through the pipe wall, achieving heat exchange. The cooled natural gas flows out of the heat exchange tube mechanism and converges at the exhaust pipe 102 for discharge. Throughout the process, the protective net component protects the cooling tube mechanism. When it is necessary to check the connection status of relevant components of the cooling tube mechanism, the movable door 701 can be opened for inspection.

[0031] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A natural gas liquefaction waste heat recovery device, comprising a displacement tank (1), wherein both ends of the displacement tank (1) are respectively connected to an air inlet pipe (101) for air intake and an exhaust pipe (102) for exhaust, characterized in that, The heat exchange tube mechanism is provided inside the replacement box (1). The heat exchange tube mechanism is connected to the intake pipe (101) and the exhaust pipe (102) through a diversion block mechanism. The hot gas input from the intake pipe (101) is diverted to exchange heat and then flows back and merges to be discharged from the exhaust pipe (102). Vertical plates (2) are provided at both ends of the replacement box (1) to divide the interior of the replacement box (1) into two sets of first cavity areas (201) and a second cavity area (202) between the two sets of first cavity areas (201). The interior of the second cavity area (202) is divided from top to bottom by two sets of horizontal plates (203) and two sets of vertical plates (2), dividing the second cavity area (202) into three layers. A cooling tube mechanism connecting the three layers of the corresponding second cavity area (202) is provided on the outside of the replacement box (1).

2. The natural gas liquefaction waste heat recovery device according to claim 1, characterized in that: Each of the aforementioned diversion block mechanisms includes a diversion block body (5) disposed inside the second cavity region (202). Diversion channels (501) are provided at the ends of the two diversion block bodies (5) that are far apart from each other. The diversion channels (501) are divided into three groups that are respectively connected to the interior of the corresponding second cavity region (202). The heat exchange tube mechanism inside the second cavity region (202) corresponds one-to-one with the diversion channels (501) at the adjacent ends of the two diversion tubes.

3. The natural gas liquefaction waste heat recovery device according to claim 2, characterized in that: Each of the aforementioned diversion block bodies (5) is a trapezoidal and high-temperature resistant metal block.

4. The natural gas liquefaction waste heat recovery device according to claim 1, characterized in that: The cooling pipe mechanism includes a pump (4) installed outside the replacement box (1). The input end and output end of the pump (4) are respectively connected to cooling pipe one (3) and cooling pipe two (302). The ends of cooling pipe one (3) and cooling pipe two (302) that are far apart from each other are connected to the two sides inside the corresponding second cavity area (202). The ends of cooling pipe one (3) and cooling pipe two (302) that are close to each other are detachably connected to the pipes at the corresponding ends of the pump (4) through flange (301).

5. The natural gas liquefaction waste heat recovery device according to any one of claims 1-4, characterized in that: A protective net component is installed on the outside of the replacement box (1). The protective net component includes a protective net cover (7). The cooling pipe mechanism located outside the replacement box (1) is covered inside the protective net cover (7). The upper part of the protective net cover (7) is movably connected with a movable door (701) corresponding to the front and rear of the pump (4).

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