An automatic temperature control device for drying sodium hypophosphite

Abstract

This utility model relates to the field of crystal drying technology, and in particular to an automatic temperature control device for drying sodium hypophosphite. The device includes a dryer body with a steam delivery pipe connected to its air inlet. From left to right, a manual valve, a high-precision pressure sensor, and a pneumatic regulating valve are sequentially installed on the surface of the steam delivery pipe. Inside the dryer body, an electromagnetic flow sensor, a temperature sensor, and an infrared online moisture detector are installed. The outputs of these sensors are electrically connected to a DCS system unit. The electromagnetic flow sensor, temperature sensor, and infrared online moisture detector can synchronously transmit three parameters—temperature signal, feed rate signal, and moisture content signal—to the DCS system unit, dynamically adjusting the opening of the pneumatic regulating valve. This upgrades passive temperature control to active predictive adjustment, ensuring accurate moisture content of the dried material while reducing ineffective heating.

Description

Technical Field

[0001] This utility model relates to the field of crystal drying technology, specifically to an automatic temperature control device for drying sodium hypophosphite. Background Technology

[0002] Sodium hypophosphite is an inorganic compound, a white crystalline powder with strong reducing properties. It is widely used in food preservation, chemical nickel plating, flame retardants, and other fields. Because the sodium hypophosphite (crystalline) semi-finished product has a high moisture content after the centrifugation process, it must undergo a drying process to reach the moisture content required by the customer.

[0003] The current sodium hypophosphite drying equipment still uses a manual temperature control mode. When the temperature is too low, the steam heating valve is manually opened; when the temperature is too high, the steam heating valve is manually closed. The operator observes and pays attention to temperature changes. This position is operated by only one person, who must both operate the equipment on-site and pay attention to temperature changes to adjust the steam heating valve.

[0004] The above-mentioned manual temperature control greatly increases the workload of workers and has low temperature control accuracy. In addition, the above operation relies only on a single temperature signal inside the dryer for temperature control, without considering the core related factors of sodium hypophosphite drying (such as feed rate, material moisture content, and steam pressure fluctuations). This can easily lead to the temperature reaching the standard but the moisture content exceeding the standard or overheating and wasting energy. Moreover, it is impossible to recover the waste heat of the drying exhaust gas, resulting in poor energy-saving effect. In order to solve the above technical problems, we have designed an automatic temperature control device for sodium hypophosphite drying. Utility Model Content

[0005] The purpose of this utility model is to provide an automatic temperature control device for drying sodium hypophosphite, which has the advantages of automatic temperature control to reduce labor intensity, reduce manpower and increase efficiency, higher temperature control accuracy, and the ability to recover waste heat from exhaust gas, resulting in better energy saving and consumption reduction. It solves the problems of high labor intensity for operators during the drying process, inability to accurately control temperature through multiple parameters, and inability to recover waste heat from exhaust gas.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an automatic temperature control device for drying sodium hypophosphite, comprising a dryer body, wherein the air inlet end of the dryer body is connected to a steam conveying pipe, and a manual valve, a high-precision pressure sensor, and a pneumatic regulating valve are sequentially installed on the surface of the steam conveying pipe from left to right; an electromagnetic flow sensor, a temperature sensor, and an infrared online moisture detector are respectively installed inside the dryer body; the output ends of the electromagnetic flow sensor, temperature sensor, and infrared online moisture detector are electrically connected to a DCS system unit; the exhaust end on the right side of the dryer body is connected to an exhaust pipe, the top of the exhaust pipe is connected to a shell-and-tube heat exchanger, and the left side of the shell-and-tube heat exchanger is connected to a preheating gas pipe.

[0007] Preferably, the output terminal of the DCS system unit is electrically connected to the pneumatic regulating valve, and the electromagnetic flow sensor is installed at the feed inlet of the dryer body.

[0008] Preferably, the temperature sensor and the infrared online moisture detector are both installed in the middle of the dryer body, and the output end of the high-precision pressure sensor is electrically connected to the DCS system unit.

[0009] Preferably, a feed pipe is installed on the left side of the top of the dryer body, and the left side of the preheating gas pipe is connected to the feed pipe.

[0010] Preferably, the right side of the shell-and-tube heat exchanger is connected to an air inlet pipe, and the left side of the top of the shell-and-tube heat exchanger is connected to an exhaust pipe.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. Electromagnetic flow sensor, temperature sensor and infrared online moisture detector can synchronously transmit three parameters, namely temperature signal, feed rate signal and moisture content signal, to the DCS system unit, dynamically adjust the opening of pneumatic regulating valve, upgrade from passive temperature control to active predictive adjustment, ensure that the moisture content of the dried material meets the standard, and reduce ineffective heating.

[0012] 2. The high-precision pressure sensor can detect the steam pressure fluctuation in the steam delivery pipe in real time. The DCS system unit can automatically compensate the opening of the pneumatic regulating valve according to the steam pressure change, solve the problem of temperature fluctuation caused by steam network pressure fluctuation, and further improve the temperature control accuracy.

[0013] 3. By setting up a shell and tube heat exchanger, the heat of the hot and humid exhaust gas can be transferred to the internal ambient temperature air. The preheated air enters the feed pipe to preheat the crystals, reducing the heating load of steam on the cold air, reducing steam consumption, and reducing the heat loss from direct exhaust gas emissions. Attached Figure Description

[0014] Figure 1 This is a system schematic diagram of the present invention.

[0015] In the diagram: 1. Dryer body; 2. Outlet pipe; 3. Inlet pipe; 4. Shell and tube heat exchanger; 5. Exhaust gas discharge pipe; 6. Preheating gas pipe; 7. Feed pipe; 8. Pneumatic regulating valve; 9. High-precision pressure sensor; 10. Manual valve; 11. Steam delivery pipe; 12. DCS system unit; 13. Electromagnetic flow sensor; 14. Temperature sensor; 15. Infrared online moisture detector. Detailed Implementation

[0016] Please see Figure 1An automatic temperature control device for drying sodium hypophosphite includes a dryer body 1. The air inlet of the dryer body 1 is connected to a steam conveying pipe 11. From left to right, a manual valve 10, a high-precision pressure sensor 9, and a pneumatic regulating valve 8 are installed on the surface of the steam conveying pipe 11. The high-precision pressure sensor 9 is model PT124B-210 with a range of 0-2MPa. An electromagnetic flow sensor 13, a temperature sensor 14, and an infrared online moisture detector 15 are installed inside the dryer body 1. The outputs of the electromagnetic flow sensor 13, temperature sensor 14, and infrared online moisture detector 15 are electrically connected to a DCS system unit 12. The DCS system unit 12 has a built-in PID adaptive algorithm. The exhaust end on the right side of the dryer body 1 is connected to an exhaust pipe 2. The top of the exhaust pipe 2 is connected to a shell-and-tube heat exchanger 4. The shell-and-tube heat exchanger 4 is model BN100-1.0-5 and is made of 304 stainless steel. A preheating gas pipe 6 is connected to the left side of the shell-and-tube heat exchanger 4.

[0017] Please see Figure 1 The output of DCS system unit 12 is electrically connected to pneumatic regulating valve 8. Electromagnetic flow sensor 13 is installed at the feed inlet of dryer body 1. Electromagnetic flow sensor 13 is MagMaster 2000, with a range of 0-20m³ / h, and is suitable for pipe diameters of DN40-DN150.

[0018] Please see Figure 1 Temperature sensor 14 and infrared online moisture detector 15 are both installed in the middle of the dryer body 1. The infrared online moisture detector 15 is model MS350, with a detection range of 0.1%-30%, and is non-contact (detection distance 50-150mm). Temperature sensor 14 is model OS137-1, which is infrared non-contact and has a range of 0~300℃. The output terminal of high-precision pressure sensor 9 is electrically connected to DCS system unit 12.

[0019] Please see Figure 1 The feed pipe 7 is installed on the left side of the top of the dryer body 1, and the left side of the preheating gas pipe 6 is connected to the feed pipe 7.

[0020] Please see Figure 1 The right side of the shell-and-tube heat exchanger 4 is connected to the air inlet pipe 3, and the left side of the top of the shell-and-tube heat exchanger 4 is connected to the exhaust pipe 5.

[0021] During operation, after opening the manual valve 10, high-temperature steam enters the dryer body 1 through the steam delivery pipe 11 to dry the sodium hypophosphite crystals. An electromagnetic flow sensor 13 installed at the feed inlet of the dryer body 1 monitors the feed rate of the sodium hypophosphite crystals in real time. A temperature sensor 14 and an infrared online moisture detector 15 in the middle section detect the real-time moisture content and temperature of the material, respectively. These three parameters—temperature signal, feed rate signal, and moisture content signal—are synchronously transmitted to the DCS system unit 12. The DCS system unit 12 uses a built-in algorithm to dynamically adjust the opening of the pneumatic regulating valve 8. When the feed rate suddenly increases, even if the current temperature has not decreased, the DCS system unit 12 will preheat the pneumatic regulating valve 8 to prevent insufficient local temperature due to material accumulation. If the moisture content has dropped to the process requirements (e.g., ≤0.5%), even if the temperature has not reached the upper limit, the pneumatic regulating valve 8 will automatically close to prevent over-drying and ensure that the moisture content of the dried material accurately meets the standard (error ≤0.1%). Meanwhile, to reduce ineffective heating, a high-precision pressure sensor 9 installed at the front end of the pneumatic regulating valve 8 detects steam pressure fluctuations in real time. When the steam pressure drops (e.g., from 0.8MPa to 0.6MPa), the high-precision pressure sensor 9 transmits a signal to the DCS system unit 12. The DCS system unit 12 automatically compensates for the opening of the pneumatic regulating valve 8 according to the steam pressure change, appropriately increasing the valve opening. When the pressure rises, it appropriately decreases the valve opening of the pneumatic regulating valve 8 to ensure stable actual heating and solve the problem of fluctuating temperature caused by steam network pressure fluctuations. The hot and humid exhaust gas discharged from the dryer body 1 flows through the exhaust pipe 2 through the shell and tube heat exchanger 4 to transfer heat to the ambient temperature air entering from the inlet pipe 3. The preheated air enters the feed pipe 7 through the preheating pipe 6 to preheat the crystals, reducing the heating load of the steam in the steam delivery pipe 11 on the cold air, reducing steam consumption, and reducing the heat loss from direct exhaust gas emissions, resulting in better energy saving and consumption reduction.

[0022] The above embodiments are merely preferred technical solutions of this utility model and should not be considered as limitations on this utility model. The embodiments and features in these embodiments can be arbitrarily combined without conflict. However, under conditions with high safety and process requirements, these embodiments cannot be used because they cannot provide the on / off state of the second pneumatic valve. The protection scope of this utility model should be the technical solution described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the protection scope of this utility model.

Claims

1. A sodium hypophosphite drying automatic temperature control device, comprising a drying machine main body (1), characterized in that: The air inlet of the dryer body (1) is connected to a steam conveying pipe (11). From left to right, a manual valve (10), a high-precision pressure sensor (9), and a pneumatic regulating valve (8) are installed on the surface of the steam conveying pipe (11). An electromagnetic flow sensor (13), a temperature sensor (14), and an infrared online moisture detector (15) are installed inside the dryer body (1). The output ends of the electromagnetic flow sensor (13), the temperature sensor (14), and the infrared online moisture detector (15) are electrically connected to a DCS system unit (12). The exhaust end on the right side of the dryer body (1) is connected to an air outlet pipe (2). The top of the air outlet pipe (2) is connected to a shell-and-tube heat exchanger (4). The left side of the shell-and-tube heat exchanger (4) is connected to a preheating gas pipe (6).

2. The automatic temperature control device for drying sodium hypophosphite according to claim 1, characterized in that: The output of the DCS system unit (12) is electrically connected to the pneumatic regulating valve (8), and the electromagnetic flow sensor (13) is installed at the feed inlet of the dryer body (1).

3. The automatic temperature control device for drying sodium hypophosphite according to claim 1, characterized in that: The temperature sensor (14) and the infrared online moisture detector (15) are both installed in the middle of the dryer body (1), and the output end of the high-precision pressure sensor (9) is electrically connected to the DCS system unit (12).

4. The automatic temperature control device for drying sodium hypophosphite according to claim 1, characterized in that: The feed pipe (7) is installed on the left side of the top of the dryer body (1), and the left side of the preheating gas pipe (6) is connected to the feed pipe (7).

5. The automatic temperature control device for drying sodium hypophosphite according to claim 1, characterized in that: The right side of the shell-and-tube heat exchanger (4) is connected to an air inlet pipe (3), and the left side of the top of the shell-and-tube heat exchanger (4) is connected to an exhaust pipe (5).

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