Continuous reforming homogeneous mixing feed experimental system and method for a spiral wound heat exchanger

Abstract

The application provides a continuous reforming uniform mixing feed experiment system and method of a coiled tube heat exchanger, wherein: a first distribution orifice plate, a second distribution orifice plate and an outlet tube plate are sequentially and horizontally detachably arranged from an inlet end to an outlet end of a mixing cavity, a center tube extends upward from the bottom of the mixing cavity to between the second distribution orifice plate and the outlet tube plate and is vertically detachably arranged; a nozzle section between the second distribution orifice plate and the outlet tube plate on the center tube is detachably provided with a spray head; a gas flow meter and a blower are arranged on a gas pipeline connected to the bottom of the mixing cavity; a water pump and an electromagnetic flow meter are arranged on a water pipeline connected between a water storage tank and the bottom of the mixing cavity; the outlet end of the mixing cavity is provided with a tapered outlet that is contracted, and the tapered outlet is connected to the water storage tank through an outer pipeline to form a circulating pipeline. The round hole spray head is replaced by a nozzle spray head, the atomization capacity of the liquid phase is improved, and the gas-liquid mixing effect of the gas-liquid mixing device in the downcomer tank is improved.

Description

Technical Field

[0001] This invention relates to the field of continuous reforming technology in petrochemical plants, specifically to a continuous reforming uniform mixing feed experimental system and method with a wound-tube heat exchanger having anti-clogging function. Background Technology

[0002] With the development of large-scale and integrated refining and chemical plants in petrochemical facilities, continuous reforming units, in addition to producing oil and hydrogen, also serve as feedstock for ethylene and aromatics plants. Therefore, the stable production of continuous reforming units is increasingly important to enterprises. Existing continuous reforming units typically use plate-and-shell heat exchangers or straight-tube vertical heat exchangers for mixing feed. However, plate-and-shell heat exchangers suffer from poor reliability, are prone to damage and internal leaks; straight-tube vertical heat exchangers have low heat exchange efficiency, resulting in large temperature differences at the hot end, less recovered heat, and higher operating costs. To address these issues, continuous reforming units have begun to adopt wound-tube heat exchangers, making the unit compact, energy-efficient, and avoiding internal leaks. Wound-tube heat exchangers are mainly used as feed heat exchangers in continuous reforming units for waste heat utilization. The key to high-efficiency waste heat utilization lies in the uniform mixing of the gas-liquid feed; therefore, experimental setups are needed to study the uniformity of gas-liquid feed mixing in the lower tube box of the heat exchanger. The existing experimental setup uses a circular orifice jet nozzle for its liquid injection pipe. This structure results in poor liquid atomization; the liquid enters the mixing chamber as a liquid column after passing through the circular orifice and mixes with the relatively uniformly distributed gas phase after passing through the distribution plate, leading to poor mixing. Therefore, after several years of operation, the wound-tube heat exchanger often experiences a gradual increase in tube-side pressure drop. The main reason is material crystallization and blockage on the heat exchange tubes and the gas distribution orifice plate. Clearly, the columnar liquid injection during the mixing process in the wound-tube heat exchanger causes uneven liquid distribution within the mixing chamber. Combined with the reduced gas velocity due to obstruction, this results in a longer residence time of the material in the mixing chamber, leading to uneven material entry into the heat exchange tubes and a slower flow rate. Ultimately, this causes liquid accumulation on the distribution orifice plate and crystallization blockage in the heat exchange tubes, affecting heat transfer efficiency and increasing tube-side pressure drop. Summary of the Invention

[0003] To address the aforementioned shortcomings in the prior art, this invention provides a continuous reforming and uniform mixing feed experimental system and method for a wound-tube heat exchanger.

[0004] According to one aspect of the present invention, a continuous reforming uniform mixing feed experimental system for a coiled tube heat exchanger is provided, characterized in that it comprises: a mixing chamber, a water storage tank, and a first distribution orifice plate, a second distribution orifice plate, an outlet tube plate, and a central tube disposed inside the mixing chamber;

[0005] in:

[0006] The first distribution orifice plate, the second distribution orifice plate, and the outlet tube plate are horizontally and detachably arranged sequentially from the inlet end to the outlet end of the mixing chamber. The central tube extends upward from the bottom of the mixing chamber to the space between the second distribution orifice plate and the outlet tube plate, and is vertically and detachably arranged.

[0007] A spray head is detachably provided on the nozzle section of the central tube located between the second distribution orifice plate and the outlet tube plate;

[0008] A blower and a gas flow meter are respectively installed on the gas pipeline connected to the bottom of the mixing chamber;

[0009] A water pump and an electromagnetic flow meter are respectively installed on the water pipeline connecting the water storage tank and the bottom of the mixing chamber;

[0010] The outlet end of the mixing chamber is provided with a concave conical opening, which is connected to the water storage tank through an external pipe to form a circulation pipeline.

[0011] Preferably, the spray head includes: a uniform cross-section circular orifice spray head, a variable cross-section circular orifice spray head, a horizontal nozzle spray head, and a 90° nozzle spray head.

[0012] Preferably, the outer diameter of the uniform cross-section circular orifice nozzle is 50mm, and the overall height is 350mm. Multiple rings of uniform cross-section circular orifices are evenly distributed along the height direction at a height of 100-150mm from the bottom of the nozzle. The diameter of each circular orifice is 3mm, and there are 28 circular orifices in each ring. The distance between two rings is 12.5mm. The adjacent circular orifices between adjacent rings are staggered and distributed in an isosceles triangle.

[0013] Preferably, the variable cross-section circular orifice spray head has a ring of variable cross-section circular orifices at a distance of 100mm from its bottom, and the inner diameter of the variable cross-section circular orifices is 1mm and the outer diameter is 5mm.

[0014] Preferably, the horizontal nozzle spray head has an inner diameter of 50mm and an overall height of 350mm. Two rings of horizontally oriented spray nozzles are evenly distributed on the horizontal nozzle spray head at a height of 100-300mm from its bottom, with 4 spray nozzles in each ring. The adjacent spray nozzles in the upper and lower rings are staggered by 45°. The spray nozzles are equipped with detachable plugs that are compatible with them.

[0015] Preferably, the inner diameter of the 90° nozzle head is 50mm and the overall height is 350mm. Two rings of nozzles facing 90° are evenly distributed on the 90° nozzle head at a height of 100-300mm from its bottom, with 4 nozzles in each ring. The nozzles in the upper and lower rings are staggered by 45°. The nozzles are equipped with detachable plugs that are compatible with them.

[0016] Preferably, the first and second distribution perforated plates are provided with a plurality of first circular holes, wherein adjacent first circular holes are arranged in an equilateral triangle to form a first annular region; a coaxial central through hole is provided at the center of the plate for inserting the central tube.

[0017] Preferably, the diameter of the first circular hole is 10 mm, the spacing between the first circular holes is 15 mm, and the thickness of the plate is 10 mm.

[0018] Preferably, the first distribution plate is 200mm from the bottom of the mixing chamber, and the second distribution plate is 400mm from the bottom of the mixing chamber.

[0019] Preferably, the outlet tube sheet is provided with a plurality of second circular holes, and adjacent second circular holes are arranged in an equilateral triangle to form a second annular region.

[0020] Preferably, the diameter of the second circular hole is 15mm, the spacing between the second circular holes is 22mm, and the thickness of the outlet tube plate is 10mm.

[0021] Preferably, the mixing cavity, the first distribution orifice plate, the second distribution orifice plate, and / or the outlet tube sheet are made of transparent material.

[0022] Preferably, the central tube and / or the spray head are made of stainless steel.

[0023] Preferably, control valves are installed on the gas pipeline, water pipeline and / or external pipeline respectively.

[0024] Preferably, one or more pressure gauges are connected to the mixing chamber; wherein, the plurality of pressure gauges are respectively disposed in the cavity between the first distribution orifice plate and the bottom of the mixing chamber and in the cavity between the second distribution orifice plate and the outlet tube plate.

[0025] According to a second aspect of the present invention, a method for continuous reforming uniform mixing feed experimental method for a wound-tube heat exchanger is provided, comprising:

[0026] A central tube, a first distribution orifice plate, a second distribution orifice plate, and an outlet tube plate are installed inside the mixing chamber, and the required injection head is installed in the nozzle section of the central tube;

[0027] Air is controlled by a blower and a gas flow meter to enter the interior of the mixing chamber through the gas inlet, and then passes through the first and second distribution orifice plates in sequence to form a uniformly distributed gas phase.

[0028] The working fluid is controlled by a water pump and an electromagnetic flow meter to enter the central pipe from the water inlet of the mixing chamber, and forms a mist-like water phase through the spray head on the nozzle section, which mixes with the gas phase.

[0029] The mixed gas and water phases flow upward through the outlet tube sheet, then through the constricted star-shaped inlet into the external pipeline, and finally into the water storage tank for recycling of the working fluid.

[0030] By adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:

[0031] The continuous reforming uniform mixing and feeding experimental system and method for a coiled tube heat exchanger provided by the present invention solves the technical problem of poor gas phase distribution uniformity before mixing with liquid phase by adding a first distribution orifice plate, and achieves the technical effect of initially improving the gas phase distribution uniformity before mixing with liquid phase.

[0032] The continuous reforming uniform mixing feed experimental system and method for a coiled tube heat exchanger provided by the present invention solves the technical problem of insufficient uniformity of gas phase distribution before mixing with liquid phase by adding a second distribution plate after the first distribution plate, thereby achieving the technical effect of further improving the uniformity of gas phase distribution before mixing with liquid phase.

[0033] The continuous reforming uniform mixing feed experimental system and method for a coiled tube heat exchanger provided by the present invention solves the technical problem of poor gas-liquid mixing uniformity caused by existing round hole spray heads by introducing the technical means of nozzle injection head, and achieves the technical effect of fully atomizing the liquid phase and greatly improving the gas-liquid mixing uniformity.

[0034] The continuous reforming uniform mixing feed experimental system and method for wound tube heat exchangers provided by this invention solves the technical problem of excessively fast ammonium salt crystallization rate inside the tubes of wound tube heat exchangers by improving the uniformity of gas-liquid feed mixing, and achieves the technical effect of delaying the crystallization of ammonium salt inside the tubes.

[0035] The continuous reforming uniform mixing and feeding experimental system and method for wound tube heat exchangers provided by this invention solves the technical problem of the rapid increase in tube-side pressure drop of wound tube heat exchangers year by year by delaying ammonium salt crystallization to the greatest extent, and achieves the technical effect of reducing medium flow resistance and device power consumption. Attached Figure Description

[0036] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0037] Figure 1 This is a schematic diagram of the overall structure of the continuous reforming and uniform mixing feed experimental system of the wound tube heat exchanger in a preferred embodiment of the present invention.

[0038] Figure 2 Figures (a) to (c) are schematic diagrams of the overall and partial structures of the two distribution orifice plates in a preferred embodiment of the present invention; wherein, the pre-distribution orifice plate has the same structure as the distribution orifice plate and is used to make the gas phase distribution uniform; the gas phase passes through the pre-distribution orifice plate, is initially distributed uniformly, and then flows through the distribution orifice plate; after passing through the two distribution orifice plates, the gas phase is basically uniform.

[0039] Figure 3 Figures (a) to (c) are schematic diagrams of the overall and partial structures of the outlet tube sheet in a preferred embodiment of the present invention; wherein, based on the outlet tube sheet structure data of the original gas-liquid mixing device, the gas-liquid mixing experimental device was finally designed.

[0040] Figure 4 Figures (a) to (c) show schematic diagrams and structural parameters of a uniform cross-section circular hole jet head in a preferred embodiment of the present invention. In order to analyze the original jet structure, two types of jet heads with uniform cross-section circular holes and variable cross-section circular holes were designed.

[0041] Figure 5 (a) to (c) are corresponding injection heads in a preferred embodiment of the present invention; wherein, under the premise that the aerodynamic effect of the air remains unchanged, the corresponding air has a weaker carrying capacity for the water phase; therefore, for the second type of variable cross-section structure, only one ring of circular holes is designed.

[0042] Figure 6 Figures (a) and (b) are schematic diagrams and structural parameters of a horizontally oriented spray head structure in a preferred embodiment of the present invention; wherein the spray head used in the atomizing structure is similar to the spray head used in the central tube jet structure.

[0043] Figure 7 Figures (a) and (b) are schematic diagrams and structural parameters of a spray head structure with a 90° orientation in a preferred embodiment of the present invention; wherein the spray head used in the atomizing structure is similar to the spray head used in the central tube jet structure.

[0044] Figure 8 This is a flowchart illustrating the experimental method for continuous reforming and uniform mixing of feed in a wound-tube heat exchanger according to a preferred embodiment of the present invention.

[0045] In the figure, 1 is the mixing chamber, 2 is the first distribution orifice plate, 3 is the second distribution orifice plate, 4 is the outlet pipe plate, 5 is the central pipe, 6 is the nozzle section, 7 is the injection head, 7-1 is the horizontally oriented injection nozzle, 7-2 is the 90° oriented injection nozzle, 8 is the blower, 9 is the gas flow meter, 10 is the water storage tank, 11 is the water pump, 12 is the electromagnetic flow meter, 13 is the conical inlet, and 14 is the pressure gauge. Detailed Implementation

[0046] The embodiments of the present invention are described in detail below: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0047] To address the problems and shortcomings of existing wound-tube heat exchangers, this invention provides an experimental system for continuous reforming uniform mixing feed in a wound-tube heat exchanger. This system is used to study the uniformity of gas-liquid feed mixing in the lower tube box of the heat exchanger. More uniform gas-liquid mixing results in more thorough heat exchange between the mixture and the shell side after entering the tube side, while also reducing the degree of ammonium salt crystallization and pressure drop in the wound tubes. The experimental system performs gas-liquid mixing using four different spray patterns: constant cross-section circular orifice spray (original device structure), variable cross-section circular orifice (gradually expanding nozzle) spray, horizontal nozzle spray, and vertical nozzle spray. By observing the gas-liquid mixing effect of the four spray patterns, the spray pattern with the highest mixing efficiency is identified. Simultaneously, the experimental results are compared with numerical simulations to verify the reliability and rationality of the numerical values. The results obtained through this experimental system can provide a reference for improving the atomization method of the feedstock oil and circulating hydrogen mixing device in existing continuous reforming mixed-feed heat exchangers.

[0048] Specifically, such as Figure 1 As shown, the continuous reforming uniform mixing feed experimental system for the coiled tube heat exchanger provided in this embodiment may include: a mixing chamber 1, a water storage tank 10, and a first distribution orifice plate 2, a second distribution orifice plate 3, an outlet tube plate 4, and a central tube 5 disposed inside the mixing chamber 1.

[0049] in:

[0050] The first distribution orifice plate 2, the second distribution orifice plate 3, and the outlet tube plate 4 are horizontally and detachably arranged sequentially from the inlet end to the outlet end of the mixing chamber 1. The central tube 5 extends upward from the bottom of the mixing chamber 1 to between the second distribution orifice plate 3 and the outlet tube plate 4, and is vertically and detachably arranged.

[0051] The section of the central tube 5 located between the second distribution orifice plate 3 and the outlet tube plate 4 is the nozzle section 6, and the nozzle section 6 is detachably equipped with an injection head 7.

[0052] A blower 8 and a gas flow meter 9 are respectively installed in the gas path leading to the mixing chamber 1;

[0053] A water pump 11 and an electromagnetic flow meter 12 are respectively installed on the water line connecting the water storage tank 10 and the mixing chamber 1;

[0054] The outlet end of the mixing chamber 1 is provided with a concave conical opening 13, which is connected to the water storage tank 10 through an external pipe to form a circulation pipeline.

[0055] In some preferred embodiments, such as Figure 2 As shown in (a) to (c), the first distribution perforated plate 2 and the second distribution perforated plate 3 are provided with a plurality of first circular holes, wherein adjacent first circular holes are arranged in an equilateral triangle to form a first annular region; a coaxially arranged central through hole is provided at the center of the plate for inserting the central tube 5.

[0056] In some preferred embodiments, the diameter of the first circular hole is 10 mm, the spacing between the first circular holes is 15 mm, and the thickness of the plate is 10 mm.

[0057] In some preferred embodiments, the first distribution orifice plate 2 is 200 mm from the bottom of the mixing chamber, and the second distribution orifice plate 3 is 400 mm from the bottom of the mixing chamber.

[0058] In some preferred embodiments, such as Figure 3 As shown in (a) to (c), the outlet tube plate 4 is provided with multiple second circular holes, which are arranged in an equilateral triangle to form a second annular region.

[0059] In some preferred embodiments, the diameter of the second circular hole is 15 mm, the spacing between the second circular holes is 22 mm, and the thickness of the outlet tube sheet is 10 mm.

[0060] In some preferred embodiments, the spray head 7 includes: a uniform cross-section circular orifice spray head, a variable cross-section circular orifice spray head, a horizontal nozzle spray head, and a 90° nozzle spray head.

[0061] In some preferred embodiments, such as Figure 4 As shown in (a) to (c), the outer diameter of the uniform cross-section circular orifice nozzle is 50 mm and the overall height is 350 mm. Multiple rings of uniform cross-section circular orifices are evenly distributed along the height direction at a height of 100-150 mm from the bottom of the uniform cross-section circular orifice nozzle. The diameter of the uniform cross-section circular orifice is 3 mm. There are 28 circular orifices in each ring, and the distance between two rings is 12.5 mm. The adjacent circular orifices between two adjacent rings are staggered and distributed in an isosceles triangle.

[0062] In some preferred embodiments, such as Figure 5 As shown in (a) to (c), the variable cross-section circular hole spray head has a ring of variable cross-section circular holes at a distance of 100mm from its bottom. The inner diameter of the variable cross-section circular holes is 1mm and the outer diameter is 5mm.

[0063] In some preferred embodiments, such as Figure 6As shown in (a) and (b), the inner diameter of the horizontal nozzle head is 50 mm and the overall height is 350 mm. Two rings of horizontally oriented nozzles 7-1 are evenly distributed at a height of 100-300 mm from the bottom of the horizontal nozzle head, with 4 nozzles in each ring. The adjacent nozzles in the upper and lower rings are staggered by 45°. The nozzles are equipped with detachable plugs that are compatible with them. These plugs are used to flexibly control the actual number of nozzles in flow according to different experimental purposes, that is, to seal the nozzles that are not in use by using the pre-fitted plugs.

[0064] In some preferred embodiments, such as Figure 7 As shown in (a) and (b), the inner diameter of the 90° nozzle head is 50 mm and the overall height is 350 mm. Two rings of nozzles 7-2 facing 90° are evenly distributed at a height of 100-300 mm from the bottom of the 90° nozzle head, with 4 nozzles in each ring. The nozzles in the upper and lower rings are staggered by 45°. The nozzles are equipped with detachable plugs that are compatible with them. The plugs are used to flexibly control the number of nozzles that actually flow according to different experimental purposes, that is, to seal the nozzles that are not in use by using the plugs.

[0065] In some preferred embodiments, such as Figure 1 As shown, the mixing chamber, the first distribution orifice plate, the second distribution orifice plate, and / or the outlet tube sheet are made of transparent material.

[0066] In some preferred embodiments, the central tube and / or the spray head are made of stainless steel.

[0067] In some preferred embodiments, such as Figure 1 As shown, control valves are installed on the gas pipeline, water pipeline and / or external pipeline respectively.

[0068] In some preferred embodiments, one or more pressure gauges are also connected to the mixing chamber; the multiple pressure gauges are respectively located in the cavity between the first distribution orifice plate and the bottom of the mixing chamber, and in the cavity between the second distribution orifice plate and the outlet tube sheet.

[0069] The continuous reforming uniform mixing feed experimental system for a wound-tube heat exchanger provided in the above embodiments of the present invention is used to study the problem of uneven gas-liquid mixing. This experimental system can improve the uniformity of gas-liquid mixing, ensuring that the gas-liquid content in each of the thousands of wound tubes is as consistent as possible after the uniformly mixed gas-liquid phase enters (reducing the unevenness of gas-liquid phase content within the thousands of wound tubes). This reduces the ammonium salt crystallization rate, thereby reducing the tube-side pressure drop, thus lowering the energy consumption of the device and ultimately ensuring high-efficiency, full-load, and stable operation. Therefore, the present invention replaces the circular orifice injector with a nozzle injector, improving the atomization capability of the liquid phase and enhancing the gas-liquid mixing effect of the gas-liquid mixing device in the lower tube box.

[0070] An embodiment of the present invention also provides an experimental method for continuous reforming and uniform mixing feed of a wound tube heat exchanger.

[0071] Specifically, such as Figure 8 As shown, the continuous reforming and uniform mixing feed experimental method for a wound-tube heat exchanger provided in this embodiment may include the following operations:

[0072] S1, a central tube, a first distribution orifice plate, a second distribution orifice plate and an outlet tube plate are installed inside the mixing chamber, and the required injection head is installed in the nozzle section of the central tube;

[0073] S2, the air is controlled by the blower and the gas flow meter to enter the interior of the mixing chamber from the gas inlet of the mixing chamber, and passes through the first distribution orifice plate and the second distribution orifice plate in sequence to form a uniformly distributed gas phase;

[0074] S3, the working fluid is controlled by a water pump and an electromagnetic flow meter to enter the central pipe from the water inlet of the mixing chamber, and forms a mist-like water phase through the spray head on the nozzle section, which mixes with the gas phase;

[0075] S4, the mixed gas and water phases flow upward through the outlet tube sheet, then through the constricted star-shaped inlet into the external pipeline, and finally into the water storage tank, for recycling of the working fluid.

[0076] It should be noted that the steps in the method provided by the present invention can be implemented using corresponding modules, devices, units, etc. in the system. Those skilled in the art can refer to the technical solution of the system to implement the steps and flow of the method. That is, the embodiments in the system can be understood as preferred examples of the method, and will not be elaborated here.

[0077] The technical solution provided by the above embodiments of the present invention will be further described in detail below with reference to a specific application example.

[0078] like Figure 1 The diagram shows the core structure of a continuous reforming and uniform mixing feed experimental system for a coiled tube heat exchanger. To facilitate observation of the gas-liquid mixing and whether the liquid can be carried out of the mixing chamber, the outer shell of the chamber is made of transparent acrylic glass in this specific application example. The first distribution orifice plate (pre-distribution orifice plate), the second distribution orifice plate (distribution orifice plate), the central tube, the nozzle, and the outlet tube plate are all detachable structures and were installed before the experiment began. The nozzle and central tube are made of stainless steel, while the rest are made of acrylic glass. Before the experiment began, the valves were opened, then the blower was turned on. After the internal airflow stabilized, the water pump was turned on, and the pump flow rate was gradually increased from low to high. Photos were taken to record the water jets being carried out of the nozzles.

[0079] In this specific application example:

[0080] The blower selected has a maximum flow rate of 1800 m³ / h. 3 The water pump selected is a CPM-158 manufactured by Zhejiang Qingxiao Technology Co., Ltd., the electromagnetic flowmeter is a HQLDE manufactured by Hongqi Instrument Co., Ltd. in September 2021, and the anemometer is a Deli DL333203, which adopts a six-blade impeller structure design and can realize rapid synchronous measurement of wind speed and wind temperature. Its measurement range is 0~30m / s, which meets the working conditions requirements of this experiment.

[0081] The pre-distribution orifice plate and the distribution orifice plate primarily function to ensure uniform gas phase distribution. First, the gas phase passes through the pre-distribution orifice plate for initial uniform distribution before flowing through the distribution orifice plate. After passing through both distribution orifice plates, the gas phase is essentially homogeneous. The structure of the two distribution orifice plates is as follows: Figure 2 As shown in (a) to (c), adjacent circular holes are arranged in an equilateral triangle pattern. The diameter of the holes is 10 mm, the spacing between the holes is 15 mm, and the thickness of the distribution orifice plate is 10 mm. It should be noted that the circular holes are only densely packed within a circular area with a diameter between 50 mm and 400 mm, with a 50 mm hole at the center to accommodate the injection head. The pre-distribution orifice plate is installed at a height of 200 mm from the bottom of the mixing chamber, and the distribution orifice plate is installed at a height of 400 mm from the bottom of the mixing chamber.

[0082] Based on the original gas-liquid mixing device's outlet tube sheet structure data, the final design of the outlet tube sheet structure for the gas-liquid mixing experimental device is shown in the schematic diagram below. Figure 3 As shown in (a) to (c), adjacent circular holes are arranged in an equilateral triangle pattern. The diameter of the holes is 15 mm, the spacing between the holes is 22 mm, and the thickness of the outlet tube sheet is 10 mm. It should be noted that the circular holes are only densely packed within a circular region with a diameter between 50 mm and 400 mm, and no circular outlet holes are designed within the central 50 mm region. A wound tube bundle is connected after the outlet tube sheet. Since Phase I only optimizes the gas-liquid mixing device, the gas-liquid mixing experimental device does not involve a wound tube bundle structure.

[0083] A uniform cross-section circular orifice nozzle, its schematic diagram and structural parameters are as follows: Figure 4 As shown in (a) to (c), the nozzle has an outer diameter of 50 mm and an overall height of 350 mm. Five concentric rings of 3 mm diameter holes are evenly distributed along the height direction from 100 mm to 150 mm above the bottom. Each ring contains 28 holes, and the distance between two rings is 12.5 mm. Furthermore, adjacent holes in adjacent rings are staggered into isosceles triangles and densely distributed.

[0084] The variable cross-section circular orifice nozzle is designed with only one ring of circular orifices; the corresponding nozzle is as follows. Figure 5 As shown in (a) to (c), the difference from the first structure lies in the type and number of circular holes. As can be seen from the enlarged view, the inner diameter of the circular holes in this variable cross-section is 1 mm and the outer diameter is 5 mm. In addition, this type of circular hole is evenly distributed only in the first ring with a height of 100 mm.

[0085] The schematic diagram and structural parameters of the horizontal nozzle spray head are as follows: Figure 6 As shown in Figures (a) and (b), the nozzles used in the atomizing structure are similar to those used in the central tube jet structure, both having an inner diameter of 50 mm and a height of 350 mm. Two rings of horizontally oriented nozzles are evenly distributed at heights of 100 mm and 300 mm, with four nozzles in each ring, totaling eight nozzles. Furthermore, adjacent nozzles in the upper and lower rings are staggered by 45°. During the experiment, the actual number of nozzles in circulation can be flexibly controlled according to different experimental objectives, i.e., unused nozzle connectors can be sealed using pre-fitted plugs. At the same time, the nozzles are not directly installed on the wall of the central tube; in actual processing, appropriate positions should be reserved according to the size of the connectors for nozzle installation.

[0086] The schematic diagram and structural parameters of the 90° nozzle injection head are as follows. Figure 7 As shown in Figures (a) and (b), the nozzles used in the atomizing structure are similar to those used in the central tube jet structure, both having an inner diameter of 50 mm and a height of 350 mm. Two rings of nozzles facing 90° are evenly distributed at heights of 100 mm and 300 mm, with four nozzles in each ring, totaling eight. Furthermore, adjacent nozzles in the upper and lower rings are staggered by 45°. During the experiment, the actual number of nozzles in circulation can be flexibly controlled according to different experimental objectives, i.e., unused nozzle connectors can be sealed using pre-fitted plugs. Meanwhile, the nozzles are not directly installed on the wall of the central tube; in actual processing, appropriate positions should be reserved according to the size of the connectors, such as 90° elbows, to install the nozzles.

[0087] This specific application example utilizes a continuous reforming and homogeneous mixing feed experimental system with a wound-tube heat exchanger. To optimize the structure of the original gas-liquid mixing device, a nozzle device widely used in liquid spraying was selected. Considering the influence of nozzle outlet orientation, two types of nozzles were designed: one with a horizontal nozzle and the other with a 90° nozzle. Additionally, two types of nozzles with perforations were designed based on the original jet atomization device. To facilitate experimental setup, all four nozzles were designed as detachable structures, secured to the central tube by threads.

[0088] The experimental methods used in this specific application example for the continuous reforming and uniform mixing feed experimental system with a wound-tube heat exchanger include:

[0089] A certain flow rate of air is drawn in by a blower, and the air flow rate can be measured by a gas flow meter. Water is drawn from a water storage tank by a pump, and the flow rate can be measured by an electromagnetic flow meter. Both the water and air circuits are equipped with valves, and the flow rates of air and water can be controlled by adjusting the valve openings. Air flows into the mixing chamber from the bottom, and after passing through the pre-distribution orifice plate and the distribution orifice plate, it is evenly distributed. Then it mixes with the water phase ejected from the nozzle, carrying the water phase upwards through the tube sheet, and flows into the outer pipe through the conical orifice, finally flowing into the water storage tank, thus achieving the circulation of the pipeline. The introduction of the outlet circulation pipe and the water storage tank enables the recycling of the working fluid, reducing unnecessary waste. Each experiment only requires unscrewing the nozzle used in the previous experiment from the central tube and screwing on a new nozzle.

[0090] The continuous reforming uniform mixing feed experimental system and method for a coiled tube heat exchanger provided in the above embodiments of the present invention are aimed at the application of the coiled tube heat exchanger in a continuous reforming unit, mainly as a feed heat exchanger, for the purpose of waste heat utilization. The key to high efficiency of waste heat utilization lies in whether the gas-liquid feed is mixed uniformly. The uniformity of gas-liquid feed mixing in the lower tube box of the heat exchanger is studied. The circular orifice spray head is replaced with a nozzle spray head, which improves the atomization ability of the liquid phase and improves the gas-liquid mixing effect of the gas-liquid mixing device in the lower tube box.

[0091] Any matters not covered in the above embodiments of the present invention are well-known in the art.

[0092] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A continuous reforming and uniform mixing feed experimental system for a wound-tube heat exchanger, characterized in that, include: A mixing chamber, a water storage tank, and a first distribution perforation plate, a second distribution perforation plate, an outlet pipe plate, and a central pipe disposed inside the mixing chamber; in: The first distribution orifice plate, the second distribution orifice plate, and the outlet tube plate are horizontally and detachably arranged sequentially from the inlet end to the outlet end of the mixing chamber. The central tube extends upward from the bottom of the mixing chamber to the space between the second distribution orifice plate and the outlet tube plate, and is vertically and detachably arranged. A spray head is detachably provided on the nozzle section of the central tube located between the second distribution orifice plate and the outlet tube plate; A blower and a gas flow meter are respectively installed on the gas pipeline connected to the bottom of the mixing chamber; A water pump and an electromagnetic flow meter are respectively installed on the water pipeline connecting the water storage tank and the bottom of the mixing chamber; The outlet end of the mixing chamber is provided with a concave conical opening, which is connected to the water storage tank through an external pipe to form a circulation pipeline.

2. The continuous reforming and uniform mixing feed experimental system for a wound-tube heat exchanger according to claim 1, characterized in that, The spray head includes: a uniform cross-section circular orifice spray head, a variable cross-section circular orifice spray head, a horizontal nozzle spray head, and a 90° nozzle spray head.

3. The continuous reforming and uniform mixing feed experimental system for a wound-tube heat exchanger according to claim 2, characterized in that, The outer diameter of the uniform cross-section circular orifice nozzle is 50mm, and the overall height is 350mm. Multiple rings of uniform cross-section circular orifices are evenly distributed along the height direction at a height of 100-150mm from the bottom of the nozzle. The diameter of each circular orifice is 3mm, and there are 28 circular orifices in each ring. The distance between two rings is 12.5mm. The adjacent circular orifices between adjacent rings are staggered and distributed in an isosceles triangle.

4. The continuous reforming and uniform mixing feed experimental system for a wound-tube heat exchanger according to claim 2, characterized in that, The variable cross-section circular orifice spray head has a ring of variable cross-section circular orifices located 100mm from its bottom. The inner diameter of the variable cross-section circular orifice is 1mm and the outer diameter is 5mm.

5. The continuous reforming and uniform mixing feed experimental system for a wound-tube heat exchanger according to claim 2, characterized in that, The horizontal nozzle has an inner diameter of 50mm and an overall height of 350mm. Two rings of horizontally oriented nozzles are evenly distributed on the horizontal nozzle at a height of 100-300mm from its bottom, with 4 nozzles in each ring. The adjacent nozzles in the upper and lower rings are staggered by 45°. The nozzles are equipped with detachable plugs that are compatible with them.

6. The continuous reforming and uniform mixing feed experimental system for a wound-tube heat exchanger according to claim 2, characterized in that, The inner diameter of the 90° nozzle is 50mm and the overall height is 350mm. Two rings of nozzles facing 90° are evenly distributed on the 90° nozzle head at a height of 100-300mm from its bottom. Each ring has 4 nozzles, and the adjacent nozzles in the upper and lower rings are staggered by 45°. The nozzles are equipped with detachable plugs that are compatible with them.

7. The experimental system for continuous reforming and uniform mixing feed of a wound-tube heat exchanger according to claim 1, characterized in that, The first and second distribution perforated plates are provided with a plurality of first circular holes, wherein adjacent first circular holes are arranged in an equilateral triangle to form a first annular region; a coaxial central through hole is provided at the center of the plate for inserting the central tube; and / or The outlet tube sheet is provided with multiple second circular holes, which are arranged in an equilateral triangle to form a second annular region.

8. The continuous reforming and uniform mixing feed experimental system for a wound-tube heat exchanger according to claim 7, characterized in that, It also includes any one or more of the following: The diameter of the first circular hole is 10mm, the spacing between the first circular holes is 15mm, and the thickness of the plate is 10mm; The first distribution orifice plate is 200mm away from the bottom of the mixing chamber, and the second distribution orifice plate is 400mm away from the bottom of the mixing chamber; The diameter of the second circular hole is 15mm, the spacing between the second circular holes is 22mm, and the thickness of the outlet tube plate is 10mm.

9. The experimental system for continuous reforming and uniform mixing feed of a wound-tube heat exchanger according to any one of claims 1-8, characterized in that, It also includes any one or more of the following: The mixing cavity, the first distribution orifice plate, the second distribution orifice plate, and / or the outlet tube sheet are made of transparent material; -The central tube and / or the injection head are made of stainless steel. - Control valves are respectively installed on the gas pipeline, water pipeline and / or external pipeline; - One or more pressure gauges are also connected to the mixing chamber; wherein, the plurality of pressure gauges are respectively located in the cavity between the first distribution orifice plate and the bottom of the mixing chamber and in the cavity between the second distribution orifice plate and the outlet tube plate.

10. A method for continuous reforming and uniform mixing feed experiment in a wound-tube heat exchanger, characterized in that, include: A central tube, a first distribution orifice plate, a second distribution orifice plate, and an outlet tube plate are installed inside the mixing chamber, and the required injection head is installed in the nozzle section of the central tube; Air is controlled by a blower and a gas flow meter to enter the interior of the mixing chamber through the gas inlet, and then passes through the first and second distribution orifice plates in sequence to form a uniformly distributed gas phase. The working fluid is controlled by a water pump and an electromagnetic flow meter to enter the central pipe from the water inlet of the mixing chamber, and forms a mist-like water phase through the spray head on the nozzle section, which mixes with the gas phase. The mixed gas and water phases flow upward through the outlet tube sheet, then through the constricted star-shaped inlet into the external pipeline, and finally into the water storage tank for recycling of the working fluid.

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