A shell-and-tube evaporator and a continuous production device for soluble inorganic salts

Abstract

The utility model relates to chemical material synthetic equipment technical field discloses a kind of tubular evaporator and soluble inorganic salt continuous production device, tubular evaporator includes multiple tubular evaporator, each tubular evaporator is contained with the evaporation pipe body for material flow and is set to the evaporation pipe body outer periphery, for steam circulation heat exchange jacket;At least two tubular evaporators are connected in series to form an evaporation column, and at least two evaporation columns are connected in parallel.The soluble inorganic salt continuous production device includes the above tubular evaporator, buffer tank, gas-liquid separator, tubular condenser and crystallization tank;Buffer tank is communicated with each material inlet of tubular evaporator by liquid inlet branch pipe, gas-liquid separator one end is communicated with tubular evaporator by concentrated liquid liquid accumulation pipe, other end is communicated with crystallization tank by discharge header, and density meter is equipped on discharge header and is on-line detected.The device can realize soluble inorganic salt continuous production, and give consideration to evaporation efficiency and product quality control.

Description

Technical Field

[0001] This utility model relates to the field of chemical material synthesis equipment technology, specifically to a tubular evaporator and a continuous production device for soluble inorganic salts. Background Technology

[0002] In the production of soluble inorganic salts, evaporation and concentration are the core processes for converting dilute solutions into high-concentration concentrates, directly impacting production capacity, product purity, and energy costs. Currently, downstream industries are demanding higher standards for product quality stability and production continuity, and the chemical industry also needs to conserve energy and reduce consumption. The shortcomings of traditional canned evaporators and their supporting equipment are no longer adequate for industrial needs. Traditional soluble inorganic salt production often employs canned evaporators, which have large single-tank volumes and long material residence times. Uneven heat exchange in certain areas can easily lead to overheating, causing inorganic salt crystals to crystallize and adhere to the heat exchange tube walls, forming scale. Scale not only reduces the heat exchange efficiency of the tubes but also reduces the flow cross-section, slowing material flow. More importantly, existing canned evaporators lack real-time detection mechanisms for scale formation. Cleaning is only performed when evaporation efficiency suddenly drops (e.g., increased steam consumption but slower concentration) or when pipes become blocked. Each cleaning requires disassembling internal components, which is time-consuming and severely disrupts production continuity. Frequent shutdowns result in insufficient effective operating time for some production lines. Furthermore, the simple heat exchange chamber design of canned evaporators leads to uneven steam distribution within the chamber, insufficient contact with the heat exchange tubes, low heat utilization efficiency, and high steam consumption, failing to meet energy-saving requirements. Problems in material handling and quality control are equally prominent: during the material transport from the buffer tank to the evaporator, the existing equipment lacks precise real-time flow monitoring components and relies solely on fixed pipelines, making it impossible to obtain real-time feed data. This prevents operators from promptly detecting equipment malfunctions. For example, if slight scaling on a group of heat exchange tubes inside the tank increases resistance and indirectly reduces the feed rate in that area, the lack of flow meter feedback means operators can only detect the change when the scaling worsens and overall evaporation efficiency declines, missing the opportunity for early cleaning and further increasing the difficulty of subsequent cleaning and downtime losses.

[0003] In addition, the density detection of concentrates often adopts offline sampling methods, which requires sending samples to the laboratory for analysis. The test results are delayed. If the concentration of the concentrate is found to be unqualified, some unqualified materials have already entered the subsequent crystallization process. This not only affects the purity of the product, but also requires the unqualified materials to be re-evaporated, increasing energy consumption and production costs, making it difficult to achieve continuous production. In summary, there is an urgent need to propose a tubular evaporator and a continuous production device for soluble inorganic salts that can improve evaporation efficiency, as well as enhance the stability of material concentration and the timeliness of quality control. Utility Model Content

[0004] The purpose of this invention is to provide a tubular evaporator and a continuous production device for soluble inorganic salts, which can improve evaporation efficiency and production continuity, while ensuring the stable quality of the concentrate for the production of soluble inorganic salts.

[0005] To achieve the above objectives, this utility model provides the following technical solution: A shell-and-tube evaporator includes multiple tube evaporators; each tube evaporator includes an evaporating tube body and a heat exchange jacket fitted around the outer periphery of the evaporating tube body; the evaporating tube body is used for material flow, and the heat exchange jacket is used for steam flow; at least two of the tube evaporators are connected in series to form an evaporation column; at least two evaporation columns are arranged in parallel.

[0006] Preferably, the tubular evaporator further includes a liquid inlet pipe corresponding to each of the evaporation columns and a concentrated liquid collection pipe; each evaporation tube body has a material inlet and a material outlet; each liquid inlet pipe is connected to the material inlet of the tubular evaporator located at the beginning of each evaporation column, for distributing the material to each evaporation column; the concentrated liquid collection pipe is directly connected to the material outlet of the tubular evaporator located at the end of each evaporation column, for collecting the material flowing out of each evaporation column.

[0007] Preferably, each of the liquid inlet pipes is equipped with a feed solenoid valve and a flow meter.

[0008] Preferably, the heat exchange jacket of each of the tubular evaporators is provided with a steam inlet and a condensate outlet.

[0009] A continuous production apparatus for soluble inorganic salts includes the aforementioned tubular evaporator, buffer tank, gas-liquid separator, tubular condenser, and crystallizer. The buffer tank is connected to each material inlet of the tubular evaporator via the liquid inlet pipe. One end of the gas-liquid separator is connected to each material outlet of the tubular evaporator via the concentrated liquid collection pipe. The other end of the concentrated liquid collection pipe is connected to the gas inlet of the tubular condenser. The other end of the gas-liquid separator is connected to the crystallizer via the discharge main pipe, and an online density meter is installed on the discharge main pipe.

[0010] Preferably, the discharge main pipe is also equipped with a buffer tank for the material to be inspected, and the online density meter is installed on the discharge pipe of the buffer tank for the material to be inspected.

[0011] Preferably, the discharge pipeline is also connected to a qualified product discharge pipeline and a non-qualified product discharge pipeline located downstream of the online density meter. Each of the qualified product discharge pipeline and the non-qualified product discharge pipeline is equipped with a discharge solenoid valve. The qualified product discharge pipeline is connected to the crystallization tank, and the non-qualified product discharge pipeline is connected to a non-qualified material collection tank.

[0012] Preferably, the shell-and-tube condenser is equipped with a vacuum interface.

[0013] Preferably, the shell-and-tube condenser is further provided with a cooling water inlet and a cooling water outlet.

[0014] Preferably, the cooling water outlet and the condensate outlet are both connected to a cooling water recovery tank.

[0015] The beneficial effects of this utility model are: 1. The shell-and-tube evaporator designed in this utility model can ensure efficient heat exchange between materials and steam, reduce heat loss, and improve the thermal utilization efficiency of a single shell-and-tube evaporator. It allows materials to be gradually concentrated within a single evaporation column, meeting the concentration ratio requirements of soluble inorganic salt production. The parallel arrangement of at least two evaporation columns can improve the overall material handling capacity while ensuring the concentration effect, adapting to different production capacity requirements. At the same time, combined with the flow monitoring of the inlet pipe, it can also detect the scaling of the evaporation tubes in the column in a timely manner through the flow changes of each evaporation column, avoiding downtime losses caused by untimely scaling detection in traditional equipment, and ensuring the continuity of the evaporation process.

[0016] 2. This invention integrates a tubular evaporator, a buffer tank, a gas-liquid separator, a tubular condenser, and a crystallizer to form a complete "feed-evaporation-separation-crystallization" production chain. The online density meter monitors the density of the concentrate flowing from the gas-liquid separator in real time, allowing for timely detection and adjustment of parameters in the preceding evaporation stages (such as steam supply and material flow rate), reducing problems like insufficient purity and uneven particle size in the crystallized product caused by abnormal concentration. Compared to traditional offline sampling and density testing, real-time density monitoring significantly shortens the detection lag time, ensuring stable quality for each batch of concentrate and improving the pass rate of the final soluble inorganic salt product. Attached Figure Description Figure 1 This is a schematic diagram of the structure of the continuous production device for soluble inorganic salts according to Embodiment 2 of this utility model; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3 This is a schematic diagram of the structure of the shell-and-tube evaporator according to Embodiment 1 of this utility model; Figure 4 This is a schematic diagram of the structure of the tubular evaporator in Embodiment 1 of this utility model.

[0017] Reference numerals: 10-Shell-tube evaporator, 11-Tube evaporator, 111-Evaporator tube body, 112-Heat exchange jacket, 113-Steam inlet, 12-Feed solenoid valve, 13-Flow meter, 14-Concentrate collection pipe, 20-Gas-liquid separator, 30-Buffer tank for material to be inspected, 31-Discharge pipeline, 32-Discharge solenoid valve, 33-Vacuum interface, 40-Online density meter, 50-Collection tank for non-conforming material, 60-Crystallization tank, 70-Buffer tank, 80-Shell-tube condenser, 90-Cooling water recovery tank. Detailed Implementation

[0018] The specific embodiments of this utility model are described below with reference to the accompanying drawings.

[0019] Example 1 like Figures 3 to 4 As shown, this embodiment discloses a shell-and-tube evaporator 10, including multiple tubular evaporators 11. Each tubular evaporator 11 includes an evaporation tube body 111 and a heat exchange jacket 112 sleeved around the outer periphery of the evaporation tube body 111. The evaporation tube body 111 is used to allow the flow of a dilute solution of soluble inorganic salts (i.e., the material to be processed), providing a stable evaporation channel for the material and ensuring that the material can flow continuously in the tube and complete the evaporation of water. The heat exchange jacket 112 is used to allow the flow of heating steam. The steam transfers heat to the material inside the tube by contacting the tube wall of the evaporation tube body 111, thereby increasing the temperature of the material and vaporizing the water, providing heat support for subsequent concentration. This jacketed design can increase the heat exchange area between the steam and the material, avoid the problem of uneven local heat exchange in traditional canned evaporators, and improve the heat utilization efficiency.

[0020] To further optimize concentration and processing efficiency, at least two tubular evaporators 11 are connected in series along the material flow direction to form an evaporation column. The material enters from the material inlet of the first tubular evaporator 11, undergoes initial evaporation and concentration, and then flows into subsequent tubular evaporators 11 for further evaporation. This multi-stage evaporation gradually increases the material concentration, meeting the concentration ratio requirements for soluble inorganic salt production, while avoiding the problems of excessively long material residence time and scaling caused by excessively long single evaporation tubes. Furthermore, by connecting at least two evaporation columns in parallel, multiple streams of material can be evaporated simultaneously, increasing the overall evaporation capacity.

[0021] The shell and tube evaporator 10 also includes a liquid inlet pipe corresponding to each evaporation column and a concentrated liquid collection pipe: each evaporation tube body 111 is provided with a material inlet and a material outlet. The liquid inlet pipe is connected to the material inlet of the first tube evaporator 11 of each evaporation column, which can accurately distribute the material to be evaporated to each evaporation column. The concentrated liquid collection pipe is directly connected to the material outlet of the last tube evaporator 11 of each evaporation column, which can collect the concentrated material after all evaporation columns have been completed. Each inlet pipe is equipped with a feed solenoid valve 12 and a flow meter 13. The feed solenoid valve 12 can adjust the material flow rate into the corresponding evaporation column by controlling the valve opening, thus achieving flexible control of the feed rate. The flow meter is used to monitor the material flow rate data in the inlet pipe in real time. When scaling occurs in the tubular evaporator 11 of a certain evaporation column, the flow cross section inside the pipe will shrink, resulting in a decrease in material velocity and flow rate. The flow meter 13 can detect this change in time, providing operators with a scaling warning, avoiding the problem of scaling that is only discovered when the efficiency drops sharply or the pipeline is blocked, as is the case with traditional evaporators, and ensuring continuous operation of the equipment. In addition, each tubular evaporator 11's heat exchange jacket 112 is equipped with a steam inlet and a condensate outlet. The steam inlet is used to introduce heating steam into the heat exchange jacket 112, and the condensate outlet is used to discharge the condensate formed after the steam releases heat, ensuring that heating steam can continuously enter the jacket and condensate can be discharged in time, maintaining stable heat exchange efficiency and avoiding condensate accumulation that affects steam flow and heat exchange effect. Example 2 like Figures 1 to 2 As shown, this embodiment provides a continuous production apparatus for soluble inorganic salts, including the tubular evaporator 10 of Embodiment 1, as well as a buffer tank 70, a gas-liquid separator 20, a tubular condenser 80, and a crystallizer 60. In this embodiment, a control system is also provided to control the functional coordination of each unit, thereby completing the continuous production of soluble inorganic salts from dilute solutions to crystalline products.

[0022] The buffer tank 70 is used to temporarily store the dilute solution of soluble inorganic salts to be evaporated. In this embodiment, a feed valve and a feed pump are provided between the buffer tank 70 and the inlet pipe described in Embodiment 1. The outlet of the buffer tank 70 is connected to one end of the feed valve, and the other end of the feed valve is connected to the inlet of the feed pump. The feed valve can control the flow of material from the buffer tank 70 to the feed pump. The operator can open or close the valve according to the feeding requirements of the shell-and-tube evaporator 10 to prevent material from accumulating in the feed pump. The outlet of the feed pump is connected to each material inlet of the shell-and-tube evaporator 10 through the inlet pipe, serving as the power source for material to enter the shell-and-tube evaporator 10 from the buffer tank 70. The feed pump can stably deliver the dilute solution to each evaporation column, ensuring that material enters the shell-and-tube evaporator 10 during the initial feeding stage.

[0023] One end of the gas-liquid separator 20 is connected to the material outlets of the tubular evaporator 10 via a concentrate collection pipe. Its function is to separate the gas-liquid mixture (concentrate and steam) discharged from the tubular evaporator 10. To improve separation efficiency, the preferred gas-liquid separator 20 in this embodiment also integrates a cooling function. A cooling chamber is provided on its tank wall or inside, with corresponding cooling water inlet and outlet for cooling the concentrate. Cooling water enters the cooling chamber from the cooling water inlet and exchanges heat with the mixture inside the gas-liquid separator 20, further reducing the steam temperature and promoting rapid condensation of the steam into liquid water. This reduces the moisture content in the gas phase, improves the concentration stability of the concentrate, and reduces the processing load of the subsequent tubular condenser 80, optimizing overall energy consumption. After separation, the liquid phase (concentrate) remains at the bottom of the gas-liquid separator 20, while the gas phase (a small amount of incompletely condensed steam) is discharged from the top outlet and enters the condenser through the gas inlet of the tubular condenser 80, connected to the other end of the concentrate collection pipe, achieving complete condensation and recovery of the steam. The shell-and-tube condenser 80 is equipped with a vacuum interface 33, which is connected to an external vacuum system. This system is the core driving force for the material flow in the evaporator and subsequent pipelines. After the vacuum system is activated, a negative pressure is formed inside the shell-and-tube condenser 80. This negative pressure is transmitted sequentially through the pipelines to the gas-liquid separator 20, the concentrate collection pipe, and the shell-and-tube evaporator 10. This causes the material in the evaporator to flow from the beginning to the end under the action of negative pressure. At the same time, it drives the concentrate in the gas-liquid separator 20 to move to the subsequent pipelines, realizing the power connection of "initial delivery by the feed pump + continuous drive by negative pressure". In addition, the shell-and-tube condenser 80 is also equipped with a cooling water inlet and a cooling water outlet. The cooling water enters the outside of the condenser tube bundle from the inlet and exchanges heat with the steam in the tube bundle, causing the steam to condense into water. The condensate is discharged from the condensate outlet. The cooling water absorbs heat and rises in temperature before being discharged from the cooling water outlet, ensuring that the steam condensation process is carried out efficiently. The other end of the gas-liquid separator 20 is connected to the material buffer tank 30 to be tested via the discharge main pipe. The material buffer tank 30 is equipped with a vacuum interface 33, which works in conjunction with the vacuum system of the shell-and-tube condenser 80 to balance the gas pressure inside the material buffer tank 30. When negative pressure is transmitted to the material buffer tank 30, the vacuum interface 33 can adjust the negative pressure intensity of the material buffer tank 30 to avoid excessive negative pressure causing the material flow rate to be too fast and affecting the detection accuracy, or insufficient negative pressure causing the material to stagnate, thus ensuring that the material flows steadily into the buffer tank. The discharge pipe 31 of the material buffer tank 30 is equipped with an online density meter 40, which can detect the density of the concentrate in real time during the continuous flow of the material. Without stopping the material delivery, the density data can be used to directly determine whether the concentration of the concentrate has reached the crystallization requirements, avoiding the lag of traditional offline sampling and testing, and ensuring that unqualified materials can be screened in a timely manner. The discharge pipeline 31 of the buffer tank 30 for the material to be inspected is also connected to the qualified product discharge pipeline 31 and the unqualified product discharge pipeline 31 located downstream of the online density meter 40. Both pipelines are equipped with discharge solenoid valves 32: when the online density meter 40 detects that the density of the concentrate meets the set value (qualified), the control system opens the discharge solenoid valve of the qualified product discharge pipeline 31 and closes the discharge solenoid valve of the unqualified product pipeline. The qualified concentrate flows into the crystallization tank 60 under negative pressure, and soluble inorganic salt crystallization is achieved by cooling or further evaporation of solvent. When the density is found to be unqualified, the discharge solenoid valve of the unqualified product pipeline opens and the discharge solenoid valve of the qualified product discharge pipeline 31 closes. The unqualified concentrate is transported to the unqualified material collection tank, and can be transported back to the buffer tank 70 for further concentration to reduce material waste. Each cooling water outlet and the condensate outlet of the shell-and-tube condenser 80 are connected to a cooling water recovery tank 90. ​​The heated cooling water and condensate discharged from the shell-and-tube condenser 80, as well as the heated cooling water discharged from the cooling chamber of the gas-liquid separator 20, all flow into the recovery tank. After sedimentation, filtration and other treatments, they can be reused as cooling water in the gas-liquid separator 20 and the shell-and-tube condenser 80, realizing the recycling of water resources, reducing the cost of production water, and reducing wastewater discharge, which meets the requirements of energy conservation and consumption reduction. Its specific working principle is as follows: Before starting the device, the control system sets the feed pump flow rate, the flow meter monitoring threshold, the acceptable density range of the online density meter 40, and the negative pressure parameters of the shell-and-tube condenser 80. After startup, the feed valve is opened first, and the dilute solution in the buffer tank 70 is transported to each inlet pipe of the shell-and-tube evaporator 10 by the feed pump. The feed solenoid valve 12 adjusts its opening according to the real-time data of the flow meter 13 to ensure a stable feed rate for each evaporation column. At the same time, the vacuum system of the shell-and-tube condenser 80 is started, and a negative pressure is formed in the condenser through the vacuum interface 33. The negative pressure is then transmitted sequentially to the gas-liquid separator 20, the concentrate collection pipe, and the evaporator. The material in the evaporator flows along the evaporation tube body 111 under the drive of the negative pressure. Heating steam is introduced into the steam inlet of the heat exchange jacket 112. The steam exchanges heat with the material, causing the water to vaporize. The gas-liquid mixture flows into the gas-liquid separator 20 through the concentrate collection pipe. Cooling water is introduced into the cooling water inlet of the gas-liquid separator 20, cooling the mixture through the cooling chamber and causing some of the vapor to condense. Then, under negative pressure, the liquid concentrate remains at the bottom of the separator, while the vapor enters the tubular condenser 80, where it is completely condensed into water by the cooling water. The condensate and the heated cooling water flow together into the cooling water recovery tank 90. ​​The concentrate in the gas-liquid separator 20 enters the material buffer tank 30 under negative pressure. The concentrate flows through an online density meter 40 for real-time detection: if it passes, it enters the crystallization tank 60 for crystallization; if it fails, it enters the non-conforming material collection tank for reprocessing. Finally, the crystals in the crystallization tank 60 are separated and dried to obtain a soluble inorganic salt product. The entire process, from raw material transportation to product output, operates continuously, relying on negative pressure drive and online monitoring, balancing production efficiency and product quality.

[0024] In summary, the tubular evaporators and continuous production devices for soluble inorganic salts in Embodiments 1 and 2 improve evaporation efficiency through the series-parallel design of the tubular evaporators and implement early warning of scaling in the tubular evaporators by using flow meters; moreover, the continuous production devices for soluble inorganic salts achieve continuous material processing by relying on each component and use densitometers to monitor the concentration of the concentrate online to accurately control product quality, ultimately achieving continuous production of soluble inorganic salts while balancing production efficiency and product quality.

[0025] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A shell-and-tube evaporator, characterized in that, It includes multiple tubular evaporators; each tubular evaporator includes an evaporation tube body and a heat exchange jacket fitted around the outer periphery of the evaporation tube body; the evaporation tube body is used for material flow, and the heat exchange jacket is used for steam flow; at least two of the tubular evaporators are connected in series to form an evaporation column; at least two of the evaporation columns are arranged in parallel.

2. The shell-and-tube evaporator according to claim 1, characterized in that, It also includes a liquid inlet pipe corresponding to each of the evaporation columns and a concentrate collection pipe; Each of the evaporator tubes is provided with a material inlet and a material outlet; Each of the liquid inlet pipes is connected to the material inlet of the tubular evaporator located at the beginning of each of the evaporation columns, for distributing the material to each of the evaporation columns; The concentrate collection pipe is directly connected to the material outlet of the tubular evaporator located at the end of each of the evaporation columns, and is used to collect the material flowing out of each of the evaporation columns.

3. A shell-and-tube evaporator according to claim 2, characterized in that, Each of the aforementioned inlet pipes is equipped with an inlet solenoid valve and a flow meter.

4. A shell-and-tube evaporator according to claim 3, characterized in that, Each of the tubular evaporators has a steam inlet and a condensate outlet in its heat exchange jacket.

5. A continuous production apparatus for soluble inorganic salts, characterized in that, Includes the tubular evaporator, buffer tank, gas-liquid separator, tubular condenser, and crystallizer as described in claim 4; The buffer tank is connected to each of the material inlets of the tubular evaporator via the liquid inlet pipe; one end of the gas-liquid separator is connected to each of the material outlets of the tubular evaporator via the concentrated liquid collection pipe. The other end of the concentrate collection pipe is connected to the gas inlet of the tubular condenser. The other end of the gas-liquid separator is connected to the crystallization tank through a discharge main pipe, and an online density meter is installed on the discharge main pipe.

6. The continuous production apparatus for soluble inorganic salts according to claim 5, characterized in that, The discharge main pipe is also equipped with a buffer tank for the material to be inspected, and the online density meter is installed on the discharge pipe of the buffer tank for the material to be inspected.

7. A continuous production apparatus for soluble inorganic salts according to claim 6, characterized in that, The discharge pipeline is also connected to a qualified product discharge pipeline and a non-qualified product discharge pipeline located downstream of the online density meter. Each of the qualified product discharge pipeline and the non-qualified product discharge pipeline is equipped with a discharge solenoid valve. The qualified product discharge pipeline is connected to the crystallization tank, and the non-qualified product discharge pipeline is connected to a non-qualified material collection tank.

8. A continuous production apparatus for soluble inorganic salts according to claim 5, characterized in that, The tube-type condenser is equipped with a vacuum interface.

9. A continuous production apparatus for soluble inorganic salts according to claim 5, characterized in that, The tubular condenser is also equipped with a cooling water inlet and a cooling water outlet.

10. A continuous production apparatus for soluble inorganic salts according to claim 9, characterized in that, The cooling water outlet and the condensate outlet are both connected to a cooling water recovery tank.

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