Liquid nitrogen heater

Abstract

This invention relates to the field of liquid nitrogen equipment technology, and includes a heating device, a heat exchange device, and a pumping device. The heating device comprises a heating chamber and an electric heating assembly. The heating chamber contains the heating liquid, and the electric heating assembly heats the liquid. The heat exchange device includes a heat exchange chamber and a liquid nitrogen heat exchange structure, which is located inside the heat exchange chamber. The liquid nitrogen heat exchange structure includes a liquid nitrogen inlet and a nitrogen outlet, both connected to the outside environment. The pumping device connects the heating chamber and the heat exchange chamber. The pumping device includes a heating inlet pipe and a heating return pipe, both connected between the two. A pumping power component is installed on the heating inlet pipe. The inlet end of the heating inlet pipe is located near the electric heating assembly, and the heating return pipe is located near the nitrogen outlet. This invention can improve thermal efficiency, reduce energy consumption, reduce size, and eliminate safety hazards caused by open flames and fuel storage.

Description

Technical Field

[0001] This utility model relates to the field of liquid nitrogen equipment technology, and in particular to liquid nitrogen heaters. Background Technology

[0002] Liquid nitrogen pump trucks are specialized vehicles used in oil and gas extraction operations to produce and inject high-pressure nitrogen gas. Their core component, the liquid nitrogen heater, plays a crucial role in converting cryogenic liquid nitrogen into high-temperature, high-pressure nitrogen gas. This conversion not only provides stable power for various downhole processes but also effectively prevents cavitation and equipment embrittlement caused by direct entry of cryogenic liquid nitrogen into the pump body, fundamentally ensuring the safety and efficiency of the entire system.

[0003] Traditional liquid nitrogen heaters typically employ direct-fired evaporation technology. This works by burning fuel oil to generate high-temperature gas, which is then blown by a fan onto the outer wall of the liquid nitrogen pipe. Heat exchange between the air and the pipe wall heats and vaporizes the liquid nitrogen. However, due to air's low specific heat capacity and thermal conductivity, its heat transfer efficiency is far from ideal. To meet the nitrogen flow and pressure requirements of practical engineering projects, these heaters often need to be designed to be bulky and heavy, causing difficulties in equipment movement and installation, significantly increasing manufacturing and operating costs, and exhibiting clear shortcomings in energy efficiency and economy. Utility Model Content

[0004] In view of this, the technical problem to be solved by this utility model is to provide a liquid nitrogen heater that can improve thermal efficiency, reduce energy consumption, reduce volume, and eliminate safety hazards caused by open flames and fuel storage.

[0005] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0006] A liquid nitrogen heater, comprising a heating device, a heat exchange device, and a pumping device;

[0007] The heating device includes a heating box and an electric heating component. The heating box is used to contain the heating liquid, and the electric heating component is used to heat the heating liquid to raise its temperature.

[0008] The heat exchange device includes a heat exchange box and a liquid nitrogen heat exchange structure. The liquid nitrogen heat exchange structure is disposed inside the heat exchange box and includes a liquid nitrogen inlet and a nitrogen outlet, both of which are connected to the outside.

[0009] The pumping device connects the heating box and the heat exchange box. The pumping device includes a heating inlet pipe and a heating return pipe that are both connected between the two. A pumping power component is installed on the heating inlet pipe. The inlet end of the heating inlet pipe is located near the electric heating component, and the heating return pipe is located near the nitrogen outlet.

[0010] Preferably, a vertical partition is installed inside the heating box, which divides the inner cavity of the heating box into a connected heating area and a return liquid area. The electric heating component is disposed in the heating area, and the heating return liquid pipe is disposed in the return liquid area.

[0011] Preferably, the heating area is connected to the bottom of the liquid return area;

[0012] The electric heating component is located at the top of the heating area, the heating return pipe is located at the bottom of the return area, and the heating box is equipped with a liquid injection port, which is located at the top of the return area.

[0013] Preferably, the electric heating assembly includes a plurality of electric heaters.

[0014] Preferably, the liquid nitrogen heat exchange structure includes a liquid nitrogen inlet pipe and a nitrogen outlet pipe;

[0015] One end of the liquid nitrogen inlet pipe is connected to the liquid nitrogen inlet, and the other end of the liquid nitrogen inlet pipe is closed. The liquid nitrogen inlet pipe is located at the bottom of the heat exchange box.

[0016] One end of the nitrogen outlet pipe is connected to the nitrogen outlet, and the other end of the nitrogen outlet pipe is closed. The nitrogen outlet pipe is located at the bottom of the heat exchange box. Several heat exchange tubes are connected between the nitrogen outlet pipe and the liquid nitrogen inlet pipe. The heat exchange tubes are arranged vertically.

[0017] Preferably, the heat exchange tube is a U-shaped heat exchange tube.

[0018] Preferably, at least one transition cylindrical component is provided between the liquid nitrogen inlet pipe and the nitrogen outlet pipe, the transition cylindrical component being hollow inside and closed at both ends;

[0019] The transition cylindrical component is connected to the liquid nitrogen inlet pipe, and the transition cylindrical component is connected to the nitrogen outlet pipe through the heat exchange pipe.

[0020] Preferably, the heat exchange box is provided with a plurality of horizontal partitions, which are arranged at equal intervals along the vertical direction. The partitions divide the interior of the heat exchange box to form heat exchange channels for the flow of heating liquid, and the heat exchange channels have an S-shaped structure.

[0021] The heat exchange tubes are arranged vertically through the horizontal partition.

[0022] Preferably, the outlet end of the heating inlet pipe is located at the top of the heat exchange box.

[0023] After adopting the above technical solution, the beneficial effects of this utility model are:

[0024] The liquid nitrogen heater of this application includes a heating device, a heat exchange device, and a pumping device. The heating device includes a heating chamber and an electric heating assembly, which heats the liquid nitrogen. The heat exchange device includes a heat exchange chamber and a liquid nitrogen heat exchange structure, which is located inside the heat exchange chamber and includes a liquid nitrogen inlet and a nitrogen outlet. The pumping device connects the heating chamber and the heat exchange chamber, and includes a heated inlet pipe and a heated return pipe, with a pumping power component installed on the heated inlet pipe. The heated liquid is stored in the heating chamber and heated to a set temperature by the electric heating assembly. Driven by the pumping power component, it is then transported to the heat exchange chamber through the heated inlet pipe. Inside the heat exchange chamber, the heated liquid and the liquid nitrogen heat exchange structure come into full contact and exchange heat, thus efficiently completing the vaporization process of the liquid nitrogen. This structure completely changes the traditional method of heat exchange relying on air and pipe walls, significantly improving heat transfer efficiency and system performance.

[0025] First, by using a high specific heat capacity medium like a heating liquid as the heat transfer medium, and heating it through an electric heating component, it undergoes thorough heat exchange with the liquid nitrogen heat exchange structure within the heat exchange box. This significantly improves heat transfer efficiency, resulting in significantly lower energy consumption and a smaller volume compared to traditional direct-fired heating methods. It also eliminates the safety hazards associated with open flames and fuel storage. Second, the liquid nitrogen heat exchange structure is entirely housed within the heat exchange box, allowing its pipe walls to have full and uniform contact and heat exchange with the flowing heating liquid. Its heat exchange efficiency and speed are far superior to traditional air convection heating. Finally, a forced circulation loop is formed by the pumping power component, the heating inlet pipe, and the heating return pipe. This loop continuously delivers the high-temperature heating liquid to the heat exchange box and returns the cooled liquid to the heating box for reheating, ensuring a continuous and stable supply of heat, avoiding heat waste, and guaranteeing the stability of the vaporization process. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Figure 1 This is a schematic diagram of the liquid nitrogen heater according to an embodiment of the present invention;

[0028] Figure 2 yes Figure 1 Internal structure diagram;

[0029] Figure 3 yes Figure 2 A structural diagram from another direction;

[0030] Figure 4 yes Figure 2 Schematic diagram of the internal structure of the heating chamber;

[0031] Figure 5 yes Figure 2 Schematic diagram of the liquid nitrogen heat exchange structure and the transverse partition;

[0032] Figure 6 yes Figure 5 A structural diagram from another direction;

[0033] In the picture:

[0034] 1. Heating device; 11. Heating box; 12. Electric heating assembly; 121. Electric heater; 13. Vertical partition; 14. Liquid injection port;

[0035] 2. Heat exchange device; 21. Heat exchange box; 22. Liquid nitrogen heat exchange structure; 221. Liquid nitrogen inlet; 222. Nitrogen outlet; 223. Liquid nitrogen inlet pipe; 224. Nitrogen outlet pipe; 225. Heat exchange tube; 226. Transition cylindrical component; 23. Horizontal partition;

[0036] 3. Pumping device; 31. Heated inlet pipe; 32. Heated return pipe; 33. Pumping power unit. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0038] like Figures 1 to 6 As shown, this utility model includes a heating device 1, a heat exchange device 2, and a pumping device 3. The heating device 1 includes a heating tank 11 and an electric heating element 12. The heating tank 11 contains the heating fluid, and the electric heating element 12 heats the heating fluid. In this application, water or antifreeze is preferably used as the heating fluid. Water has low raw material costs and a large specific heat capacity, making it a commonly used heating medium due to its wide availability and low cost. To prevent the heating fluid from freezing in cold winters, antifreeze, also known as antifreeze coolant, can be used. Antifreeze prevents freezing when the vehicle is parked in cold winters, ensuring the normal operation of the heating fluid.

[0039] The heat exchange device 2 includes a heat exchange box 21 and a liquid nitrogen heat exchange structure 22. The liquid nitrogen heat exchange structure 22 is located inside the heat exchange box 21 and includes a liquid nitrogen inlet 221 and a nitrogen outlet 222, both of which are connected to the outside. The pumping device 3 connects the heating box 11 and the heat exchange box 21. The pumping device 3 includes a heating inlet pipe 31 and a heating return pipe 32, both of which are connected between the two. A pumping power component 33 is installed on the heating inlet pipe 31. The inlet end of the heating inlet pipe 31 is located close to the electric heating component 12. This is to directly extract the heating liquid with the highest temperature from the heat source to ensure that the initial heat of the heating liquid entering the heat exchange box 21 is maximized, thereby significantly improving the heat exchange efficiency with the liquid nitrogen heat exchange structure 22. The heating return pipe 32 is located close to the nitrogen outlet 222, which can promptly guide the cooled heating liquid after heat exchange back to the heating box 11 to avoid the retention of low-temperature liquid affecting the continuity of heat exchange, while maintaining the system temperature gradient and circulation stability.

[0040] The heating liquid is stored in the heating tank 11 and heated to a set temperature by the electric heating component 12. Driven by the pumping power component 33, it is then transported to the heat exchange tank 21 through the heated liquid inlet pipe 31. Inside the heat exchange tank 21, the heating liquid comes into full contact with the liquid nitrogen heat exchange structure 22 and exchanges heat, thereby efficiently completing the vaporization process of liquid nitrogen. This structure completely changes the traditional method of heat exchange relying on air and pipe walls, significantly improving heat transfer efficiency and system performance. Preferably, the pumping power component 33 is a water pump.

[0041] In this process, firstly, a high specific heat capacity medium, the heating liquid, is used as the heat transfer medium. After being heated by the electric heating component 12, it undergoes sufficient heat exchange with the liquid nitrogen heat exchange structure 22 in the heat exchange box 21, which greatly improves the heat transfer efficiency. Compared with the traditional direct-fired heating method, the energy consumption is significantly reduced, the volume is also reduced, and the safety hazards caused by open flames and fuel storage are eliminated. Secondly, the liquid nitrogen heat exchange structure 22 is placed entirely inside the heat exchange box 21, allowing its pipe walls to have sufficient and uniform contact and heat exchange with the flowing heating liquid. Its heat exchange efficiency and speed are far higher than those of traditional air convection heating. Finally, a forced circulation loop is formed by the pumping power component 33, the heating inlet pipe 31, and the heating return pipe 32, which can continuously deliver the high-temperature heating liquid to the heat exchange box 21 and send the cooled liquid back to the heating box 11 for reheating, thereby ensuring a continuous and stable supply of heat, avoiding heat energy waste, and ensuring the stability of the vaporization process.

[0042] In this application, preferably, a vertical partition 13 is installed inside the heating chamber 11. The vertical partition 13 divides the inner cavity of the heating chamber 11 into a connected heating area and a return liquid area. The electric heating component 12 is disposed in the heating area, and the heating return liquid pipe 32 is disposed in the return liquid area. The purpose of setting the vertical partition 13 is to divide the heating chamber 11 into a heating zone and a return liquid area, to avoid the low-temperature return liquid directly impacting the electric heating component 12, to reduce heat loss caused by the mixing of hot and cold liquids, thereby improving heating efficiency and system stability.

[0043] The heating zone and the return liquid zone are connected at the bottom. The electric heating assembly 12 is located at the top of the heating zone, and the heated return liquid pipe 32 is located at the bottom of the return liquid zone. The heating box 11 has an injection port 14 located at the top of the return liquid zone. The injection port 14's location at the top of the return liquid zone facilitates liquid replenishment and venting. Low-temperature return liquid enters from the bottom and flows slowly through the bottom connecting area to the heating zone. The electric heating assembly 12, located at the top, prioritizes heating the high-temperature heating liquid, optimizing circulation and efficiency by utilizing the upward movement of the hot liquid. Preferably, the electric heating assembly 12 includes several electric heaters to improve heating efficiency through electric heating.

[0044] In this application, the liquid nitrogen heat exchange structure 22 includes a liquid nitrogen inlet pipe 223 and a nitrogen outlet pipe 224. One end of the liquid nitrogen inlet pipe 223 is connected to a liquid nitrogen inlet 221, and the other end is closed. The liquid nitrogen inlet pipe 223 is located at the bottom of the heat exchange box 21. One end of the nitrogen outlet pipe 224 is connected to a nitrogen outlet 222, and the other end is closed. The nitrogen outlet pipe 224 is located at the bottom of the heat exchange box 21. A plurality of heat exchange tubes 225 are connected between the nitrogen outlet pipe 224 and the liquid nitrogen inlet pipe 223. The heat exchange tubes 225 are vertically arranged. The heat exchange tubes 225 have a U-shaped structure.

[0045] The liquid nitrogen heat exchange structure 22 uses multiple vertical U-shaped heat exchange tubes 225 to connect the nitrogen outlet pipe 224 and the liquid nitrogen inlet pipe 223. Cryogenic liquid nitrogen enters from the bottom, evaporates upon heating in the heat exchange tubes 225, and the nitrogen gas naturally flows upward and then flows back into the nitrogen outlet pipe 224. This design significantly increases the heat exchange area, utilizes the principle of bubble self-rising to ensure smooth airflow, and the U-shaped structure effectively compensates for thermal stress. The overall structure is compact, with concentrated interfaces, facilitating installation and maintenance.

[0046] At least one transition cylindrical component 226 is also provided between the liquid nitrogen inlet pipe 223 and the nitrogen outlet pipe 224. The transition cylindrical component 226 is hollow inside and closed at both ends. The transition cylindrical component 226 is connected to the liquid nitrogen inlet pipe 223 and the nitrogen outlet pipe 224 through heat exchange pipes 225. The transition cylindrical component 226 is located between the liquid nitrogen inlet pipe 223 and the nitrogen outlet pipe 224 and is connected to both of them through heat exchange pipes 225. Its core function is to evenly distribute liquid nitrogen to each parallel heat exchange branch to ensure consistent heat exchange; at the same time, it effectively collects the nitrogen generated in each branch, balances the airflow pressure, and eliminates flow dead zones, thereby significantly improving the vaporization efficiency and the uniformity and stability of system operation.

[0047] The heat exchange box 21 is equipped with several horizontal partitions 23, which are arranged vertically at equal intervals. The partitions 23 divide the interior of the heat exchange box 21 to form heat exchange channels for the flow of heating liquid. The heat exchange channels have an S-shaped structure. The heat exchange tubes 225 are arranged vertically through the partitions 23. The outlet end of the heating liquid inlet pipe 31 is located at the top of the heat exchange box 21.

[0048] The heat exchange chamber 21 is divided into continuous, S-shaped, meandering heat exchange channels by several vertically and equidistantly fixed horizontal baffles 23. This structure significantly extends the flow path and residence time of the heating liquid within the chamber, ensuring full contact with the heat exchange tubes 225, preventing fluid short-circuiting, and greatly improving heat exchange efficiency. Simultaneously, the heat exchange tubes 225 are vertically inserted through the horizontal baffles 23, enhancing the overall structural rigidity and ensuring that each heat exchange tube 225 is uniformly flushed and heat-exchanged. The outlet end of the heating inlet pipe 31 is located at the top of the heat exchange chamber 21, allowing the high-temperature heating liquid to flow naturally downwards under gravity and form an efficient counter-current heat exchange with the upward-moving low-temperature nitrogen gas, further enhancing the heat transfer effect.

[0049] In this structure, the formation of the S-shaped heat exchange channel relies on a series of specially arranged staggered horizontal baffles 23 inside the heat exchange box 21. These vertically spaced horizontal baffles 23 are alternately fixed to the opposing inner walls of the box, with a certain gap maintained between the end of each horizontal baffle 23 and the opposite side wall. When the heating liquid enters from the top, it is blocked by each layer of horizontal baffles 23 in sequence during its flow, forcing the fluid to repeatedly change direction, flowing from the gap of the upper horizontal baffle 23 to the lower layer, and then being guided to the gap on the other side. This alternating blocking and guiding structure forces the flow path of the heating liquid to be constrained into a continuous, top-down and bottom-up S-shaped meandering trajectory, thereby significantly extending the flow rate and heat exchange time. The heat exchange tubes 225 that penetrate the horizontal baffles 23 not only play a core role in heat transfer but also provide structural support and positioning for the entire baffle system.

[0050] In use, the heating liquid in the heating chamber 11 is heated to a set temperature by the electric heating component 12, driven by the pumping power component 33, and injected from the top of the heat exchange chamber 21 through the heating inlet pipe 31. As the heating liquid flows through the S-shaped heat exchange channel formed by the horizontal partition 23 inside the heat exchange chamber 21, it undergoes thorough heat exchange with the vertically penetrating U-shaped heat exchange tubes 225. Liquid nitrogen enters the liquid nitrogen inlet pipe 223 from the liquid nitrogen inlet 221, is distributed to each U-shaped heat exchange tube 225 via the transition cylindrical component 226, absorbs heat from the heating liquid, and vaporizes into nitrogen gas. The nitrogen gas collects in the nitrogen outlet pipe 224 and is discharged from the nitrogen outlet 222. The low-temperature heating liquid, having completed heat exchange, returns to the return liquid area of ​​the heating chamber 11 via the heating return pipe 32, is guided by the vertical partition 13, and re-enters the heating area for recirculation, thus forming a continuous, stable, and efficient heat exchange process.

[0051] In summary, this application heats the liquid medium via the electric heating component 12, and the liquid undergoes thorough heat exchange through the S-shaped flow channel and U-shaped heat exchange tube 225, significantly improving vaporization efficiency. The vertical baffle 13 optimizes the temperature zoning within the heating chamber 11, avoiding heat and cold mixing losses. The transition cylindrical component 226 achieves uniform distribution and flow collection across multiple tubes, ensuring stable system operation. The overall structure is energy-efficient, compact, and emits no combustion emissions, offering significantly superior safety and thermal efficiency compared to traditional direct-fired evaporators.

[0052] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A liquid nitrogen heater, characterized in that, Includes heating devices, heat exchange devices, and pumping devices; The heating device includes a heating box and an electric heating component. The heating box is used to contain the heating liquid, and the electric heating component is used to heat the heating liquid to raise its temperature. The heat exchange device includes a heat exchange box and a liquid nitrogen heat exchange structure. The liquid nitrogen heat exchange structure is disposed inside the heat exchange box and includes a liquid nitrogen inlet and a nitrogen outlet, both of which are connected to the outside. The pumping device connects the heating box and the heat exchange box. The pumping device includes a heating inlet pipe and a heating return pipe that are both connected between the two. A pumping power component is installed on the heating inlet pipe. The inlet end of the heating inlet pipe is located near the electric heating component, and the heating return pipe is located near the nitrogen outlet.

2. The liquid nitrogen heater as described in claim 1, characterized in that, The heating chamber is equipped with a vertical partition, which divides the inner cavity of the heating chamber into a connected heating area and a return liquid area. The electric heating component is located in the heating area, and the heating return liquid pipe is located in the return liquid area.

3. The liquid nitrogen heater as described in claim 2, characterized in that, The heating area is connected to the bottom of the liquid return area; The electric heating component is located at the top of the heating area, the heating return pipe is located at the bottom of the return area, and the heating box is equipped with a liquid injection port, which is located at the top of the return area.

4. The liquid nitrogen heater as described in claim 1, characterized in that, The electric heating assembly includes several electric heaters.

5. The liquid nitrogen heater as described in claim 1, characterized in that, The liquid nitrogen heat exchange structure includes a liquid nitrogen inlet pipe and a nitrogen outlet pipe; One end of the liquid nitrogen inlet pipe is connected to the liquid nitrogen inlet, and the other end of the liquid nitrogen inlet pipe is closed. The liquid nitrogen inlet pipe is located at the bottom of the heat exchange box. One end of the nitrogen outlet pipe is connected to the nitrogen outlet, and the other end of the nitrogen outlet pipe is closed. The nitrogen outlet pipe is located at the bottom of the heat exchange box. Several heat exchange tubes are connected between the nitrogen outlet pipe and the liquid nitrogen inlet pipe. The heat exchange tubes are arranged vertically.

6. The liquid nitrogen heater as described in claim 5, characterized in that, The heat exchange tube is a U-shaped heat exchange tube.

7. The liquid nitrogen heater as described in claim 5, characterized in that, At least one transition cylindrical component is also provided between the liquid nitrogen inlet pipe and the nitrogen outlet pipe. The transition cylindrical component is hollow inside and closed at both ends. The transition cylindrical component is connected to the liquid nitrogen inlet pipe, and the transition cylindrical component is connected to the nitrogen outlet pipe through the heat exchange pipe.

8. The liquid nitrogen heater as described in claim 5, characterized in that, The heat exchange box is fixedly provided with several horizontal partitions, which are arranged at equal intervals along the vertical direction. The partitions divide the interior of the heat exchange box to form heat exchange channels for the flow of heating liquid. The heat exchange channels have an S-shaped structure. The heat exchange tubes are arranged vertically through the horizontal partition.

9. The liquid nitrogen heater as described in claim 8, characterized in that, The outlet end of the heating inlet pipe is located at the top of the heat exchange box.

Images