A thermal energy recycling reaction system for a phosphorus pentoxide production line

Abstract

The utility model discloses a kind of thermal energy circulation reaction systems of diaphosphorus pentoxide production line, including phosphorus combustion tower, exhaust pipe, yellow phosphorus heat preservation tank and air preheater, the upper end of exhaust pipe is equipped with cross pipe and cooling vertical pipe, cooling vertical pipe outside is equipped with cooling jacket at intervals, cooling cavity in cooling jacket is divided into heat absorption chamber and steam chamber, the lower part of heat absorption chamber is provided with cold water inlet, the top of steam chamber is provided with steam outlet, uniformly distributed with multiple spiral coil pipes in cooling vertical pipe, the lower end of spiral coil pipe is provided with communicating pipe, upper end is provided with upper communicating pipe, heat transfer pipe is installed in yellow phosphorus heat preservation tank, one end of heat transfer pipe is communicated with steam outlet, the other end is communicated with the medium inlet of air preheater. The device not only avoids the problem of temperature sudden drop of phosphorus combustion tower top and exhaust pipe, but also fully improves the thermal energy utilization rate of diaphosphorus pentoxide flue gas.

Description

Technical Field

[0001] This utility model belongs to the field of phosphorus chemical production technology, specifically relating to a thermal energy circulation reaction system for a phosphorus pentoxide production line. Background Technology

[0002] Phosphorus pentoxide is a white amorphous powder or hexagonal crystal. It is highly hygroscopic, soluble in water, and releases a large amount of heat, initially forming metaphosphoric acid, then orthophosphoric acid. Phosphorus pentoxide is used as a desiccant for gases and liquids; a dehydrating agent in organic synthesis; an antistatic agent for polyester resins; and a refining agent for pharmaceuticals and sugars. It is a precursor for the production of high-purity phosphoric acid, phosphates, phosphides, and phosphate esters, and its industrial applications are very extensive. Currently, the main production process for phosphorus pentoxide is the oxidation method, which involves heating and melting yellow phosphorus, then feeding it into a phosphorus combustion tower to undergo an oxidative combustion reaction with dehydrated and dried air. The resulting phosphorus pentoxide flue gas undergoes multi-stage cold crystallization to obtain the finished phosphorus pentoxide product. In the aforementioned production process, the combustion of liquid yellow phosphorus and air releases a large amount of heat. This heat, along with the phosphorus pentoxide flue gas, enters the subsequent cold crystallization tower. In existing technology, to achieve the recycling of the heat from the yellow phosphorus combustion and reduce the burden on the subsequent cold crystallization process, a waste heat recovery device is installed on the exhaust pipe at the top of the phosphorus combustion tower. This device recovers the heat from the discharged phosphorus pentoxide flue gas and then uses the recovered heat to insulate the liquid yellow phosphorus before it enters the phosphorus combustion tower. The liquid yellow phosphorus inside the combustion chamber does not solidify, thus improving the combustion efficiency of liquid yellow phosphorus. However, the aforementioned heat recovery device has the following shortcomings during use: First, the waste heat recovery device is located on the exhaust pipe at the top of the phosphorus combustion tower, which causes a sudden drop in the temperature of the exhaust pipe, leading to a decrease in the combustion temperature of the yellow phosphorus at the top of the combustion tower and resulting in incomplete combustion. Second, the waste heat recovery device located outside the exhaust pipe has a simple structure, a small contact area with the exhaust pipe, and a low heat recovery rate, failing to meet the heat energy requirements for heat preservation of liquid yellow phosphorus. Therefore, it is objectively necessary to develop a thermal energy circulation reaction system for a phosphorus pentoxide production line with a reasonable structural layout that can both ensure complete combustion of yellow phosphorus and improve the efficiency of heat recovery. Summary of the Invention

[0003] The purpose of this invention is to provide a thermal energy circulation reaction system for a phosphorus pentoxide production line with a reasonable structural layout that can both ensure the complete combustion of yellow phosphorus and improve the efficient recovery of heat energy.

[0004] The purpose of this utility model is achieved as follows: it includes a phosphorus combustion tower, a flue pipe, a yellow phosphorus insulation tank, and an air preheater. A horizontal pipe is installed at the upper end of the flue pipe, and a cooling vertical pipe is installed at the end of the horizontal pipe. Cooling jackets are spaced apart on the outer side of the cooling vertical pipe. The cavity between the cooling jackets and the cooling vertical pipe is a cooling cavity. The interior of the cooling cavity is divided into a lower heat absorption chamber and an upper steam chamber by a horizontal partition. A cold water inlet is provided at the lower part of the heat absorption chamber, and a steam outlet is provided at the top of the steam chamber. Multiple spiral coils are evenly distributed in the cooling vertical pipe near the cooling jacket. A lower connecting pipe communicating with the heat absorption chamber is provided at the lower end of the spiral coil, and an upper connecting pipe communicating with the steam chamber is provided at the upper end of the spiral coil. A heat transfer pipe communicating with the phosphorus combustion tower is installed through the interior of the yellow phosphorus insulation tank. One end of the heat transfer pipe is connected to the steam outlet through a primary steam delivery pipe, and the other end of the heat transfer pipe is connected to the medium inlet of the air preheater through a secondary steam pipe.

[0005] Compared with existing technologies, the advantages of this device are as follows: First, this device optimizes the structure of the exhaust pipe by installing a horizontal pipe and a cooling vertical pipe connected to the end of the exhaust pipe. The horizontal and cooling vertical pipes alter the flow of phosphorus pentoxide flue gas. The cooling jacket is placed on the cooling vertical pipe, thus avoiding any impact on the temperature at the exhaust pipe and preventing a sudden drop in temperature at the top of the phosphorus combustion tower and the exhaust pipe. This ensures complete combustion of liquid yellow phosphorus in the phosphorus combustion tower and improves combustion efficiency. Second, this device utilizes the cooling jacket and multiple sets of spiral coils to recover heat from the cooling vertical pipe. The cooling jacket and spiral coils significantly increase the contact area and time between the cold water and the phosphorus pentoxide flue gas, achieving efficient recovery of heat energy from the phosphorus pentoxide flue gas. The recovered heat not only fully meets the heat energy requirements for the insulation of liquid yellow phosphorus but also meets the preheating requirements for the combustion air, significantly improving the thermal energy utilization rate of the phosphorus pentoxide flue gas. It boasts advantages such as a reasonable structure, high thermal energy utilization rate, and ease of promotion and application. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the overall structure of this utility model; In the diagram: 1-Phosphorus combustion tower, 2-Exhaust pipe, 3-Yellow phosphorus insulation tank, 4-Air preheater, 5-Horizontal pipe, 6-Cooling vertical pipe, 7-Cooling jacket, 9-Steam chamber, 10-Heat absorption chamber, 11-Cold water inlet, 12-Steam outlet, 13-Spiral coil, 14-Lower connecting pipe, 15-Upper connecting pipe, 16-Heat transfer pipe, 17-Primary steam conveying pipe, 18-Secondary steam pipe, 19-Intermediate water pipe, 20-Safety valve, 21-Fume guide pipe, 22-Conical hopper, 23-Discharge pipe, 24-Heat-conducting fins, 25-Temperature meter. Detailed Implementation

[0007] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0008] like Figure 1 As shown, this utility model includes a phosphorus combustion tower 1, a flue pipe 2, a yellow phosphorus insulation tank 3, and an air preheater 4. The phosphorus combustion tower 1 is a structure used in the prior art. The phosphorus combustion tower 1 is equipped with a corresponding make-up air pipe and a phosphorus combustion spray gun. The yellow phosphorus insulation tank 3 stores liquid yellow phosphorus and has a liquid inlet and outlet. The liquid outlet is connected to the phosphorus combustion spray gun. The air preheater 4 is used to preheat the combustion air. The air preheater 4 is a shell-and-tube heat exchanger used in the prior art. The air preheater 4 has an air inlet and an air outlet. The air outlet is connected to the make-up air pipe. A horizontal pipe 5 is installed at the upper end of the flue pipe 2. A cooling vertical pipe 6 is installed at the end of the horizontal pipe 5. Cooling jackets 7 are spaced apart on the outside of the cooling vertical pipe 6. The cavity between the cooling jackets 7 and the cooling vertical pipe 6 is a cooling... The cooling cavity is divided into a lower heat absorption chamber 10 and an upper steam chamber 9 by a horizontal partition 8. The lower part of the heat absorption chamber 10 is provided with a cold water inlet 11, and the top of the steam chamber 9 is provided with a steam outlet 12. Multiple spiral coils 13 are evenly distributed in the cooling vertical pipe 6 near the cooling jacket 7. The lower end of the spiral coil 13 is provided with a lower connecting pipe 14 that communicates with the heat absorption chamber 10, and the upper end of the spiral coil 13 is provided with an upper connecting pipe 15 that communicates with the steam chamber 9. The heat transfer pipe 16 that communicates with the phosphorus combustion tower 1 is installed through the inside of the yellow phosphorus heat preservation tank 3. The top of the yellow phosphorus heat preservation tank 3 is connected to the steam outlet 12 through a primary steam delivery pipe 17, and the bottom of the yellow phosphorus heat preservation tank is connected to the medium inlet of the air preheater 4 through a secondary steam pipe 18.

[0009] The working process of this device is as follows: Phosphorus pentoxide flue gas generated during combustion in the phosphorus combustion tower 1 is discharged through the exhaust pipe 2 and enters the horizontal pipe 5. Then, it enters the cooling vertical pipe 6 through the horizontal pipe 5. The phosphorus pentoxide flue gas flows downwards in the cooling vertical pipe 6. At this time, cold water is supplied to the heat absorption chamber 10 through the cold water inlet 11. After entering the heat absorption chamber 10, the cold water absorbs the temperature outside the cooling vertical pipe 6. As the water level in the heat absorption chamber 10 rises, the cold water in the heat absorption chamber 10 will flow downwards through the lower connecting pipe... The cold water in the spiral coil 13 flows upward through the connecting pipe 14, further absorbing heat energy from the phosphorus pentoxide flue gas. After being cooled by the spiral coil 13, the phosphorus pentoxide flue gas enters the subsequent cold precipitation crystallization tower from the bottom of the cooling vertical pipe 6. Meanwhile, the cold water in the spiral coil 13 absorbs heat and its temperature gradually rises, entering the steam chamber 9 through the upper connecting pipe 15. As the cold water continuously absorbs heat energy, the steam chamber 9 continuously... Steam is generated and discharged from steam outlet 12. It then enters heat transfer pipe 16 through primary steam delivery pipe 17. Heat transfer pipe 16 is used to keep the liquid yellow phosphorus in yellow phosphorus insulation tank 3 warm, preventing the liquid yellow phosphorus from solidifying in the yellow phosphorus insulation tank 3. Finally, the steam discharged from heat transfer pipe 16 enters air preheater 4 through secondary steam delivery pipe 18 to preheat the combustion air. After the steam preheats the air, it is discharged from the medium outlet of air preheater 4. This device uses cooling jacket 7 and multiple sets of spiral coils 13 to recover heat from cooling vertical pipe 6. The cooling jacket 7 and spiral coils 13 can significantly increase the contact area and time between cold water and phosphorus pentoxide flue gas, realizing efficient recovery of heat energy from phosphorus pentoxide flue gas. The recovered heat can not only fully meet the heat energy requirements for liquid yellow phosphorus insulation, but also meet the preheating requirements for combustion air, thus fully improving the heat energy utilization rate of phosphorus pentoxide flue gas.

[0010] Furthermore, to achieve efficient recovery of the thermal energy from the phosphorus pentoxide flue gas and reduce the burden of subsequent cold precipitation crystallization treatment, at least two cooling jackets 7 are provided. The number of cooling jackets 7 can be reasonably arranged according to actual use. Multiple cooling jackets 7 are equally spaced along the vertical direction of the cooling riser 6. The cold water inlet 11 is located on the heat absorption chamber 10 of the bottom cooling jacket 7. The steam chamber 9 of the adjacent lower cooling jacket 7 is connected to the heat absorption chamber 10 of the upper cooling jacket 7 through an intermediate water pipe 19. The steam outlet 12 is located on the steam chamber 9 of each cooling jacket. Multiple steam outlets 12 are converged through a converging pipe and then connected to the primary steam... The steam delivery pipe 17 is connected, and multiple cooling jackets 7 are set up to maximize the recovery of heat energy in the phosphorus pentoxide flue gas. Cold water enters from the bottom cooling jacket 7 and then passes through the upper cooling jacket 7 in sequence. This can prolong the flow time of the cold water, allowing the cold water to fully absorb heat energy through the spiral coil 13. This can fully recover the heat energy of the phosphorus pentoxide flue gas and achieve efficient heat energy recovery. During this process, steam will be generated at the steam outlet 12 of each cooling jacket 7. In order to ensure the stability of operation, the steam generated in each steam chamber 9 will be discharged through the steam outlet 12 and then collected into the primary steam delivery pipe 17.

[0011] Furthermore, to ensure the stability of the system operation, a safety valve 20 is installed at the top of the steam chamber 9. When the pressure in the steam chamber is too high, the safety valve 20 can automatically release pressure to ensure the stable operation of the entire device.

[0012] Furthermore, in order to improve the utilization of the thermal energy of phosphorus pentoxide flue gas, and to avoid the problem of severe liquid accumulation in the pipeline due to temperature loss during steam transmission, which could lead to danger, or the problem of reduced heat utilization due to temperature loss, the primary steam transmission pipe 17 passes through the cooling riser 6 from the upper part of the cooling jacket 7 and then connects to the yellow phosphorus insulation tank 3. The primary steam transmission pipe 17 located in the phosphorus combustion tower 1 is set in a serpentine structure.

[0013] Furthermore, in order to achieve uniform heat preservation of liquid yellow phosphorus in the yellow phosphorus heat preservation tank 3, multiple heat-conducting fins 24 are evenly distributed on the outer wall of the heat transfer tube 16. The heat transfer fins have good thermal conductivity and can evenly transfer the heat energy of the steam to the yellow phosphorus heat preservation tank 3, ensuring uniform heat preservation temperature in the yellow phosphorus heat preservation tank 3.

[0014] Furthermore, a flue pipe 21 is provided at the lower part of the cooling vertical pipe 6, and a conical hopper 22 is installed at the bottom of the cooling vertical pipe 6 through a flange assembly. A discharge pipe 23 is provided at the bottom of the conical hopper 22, and a discharge valve is provided on the discharge pipe 23. During the heat exchange process between the phosphorus pentoxide flue gas and the cooling jacket 7 in the cooling vertical pipe 6, the phosphorus pentoxide in the phosphorus pentoxide flue gas is cooled into particles and falls into the conical hopper 22. The conical hopper 22 collects the phosphorus pentoxide particles, and the flue gas enters the cold precipitation crystallization device through the flue pipe 21. This can prevent the cooled phosphorus pentoxide particles from entering the cold precipitation crystallization device with the flue gas, which would affect the uniformity of phosphorus pentoxide cold precipitation crystallization. After the conical hopper 22 collects phosphorus pentoxide particles for a period of time, the discharge valve on the discharge pipe 23 is opened, and the particles are discharged periodically.

[0015] Furthermore, a temperature measuring instrument 25 is installed on the top of the yellow phosphorus heat preservation tank 3. The temperature measuring instrument 25 is a structure used in the prior art. A finished product can be purchased directly according to the power used. The temperature measuring instrument 25 can monitor the temperature inside the yellow phosphorus heat preservation tank 3 in a timely manner. Based on the monitoring, the steam flow rate entering the yellow phosphorus heat preservation tank 3 can be controlled.

Claims

1. A thermal energy circulation reaction system for a phosphorus pentoxide production line, comprising a phosphorus combustion tower (1), a flue pipe (2), a yellow phosphorus insulation tank (3), and an air preheater (4), characterized in that: A horizontal pipe (5) is installed at the upper end of the exhaust pipe (2), and a cooling vertical pipe (6) is installed at the end of the horizontal pipe (5). Cooling jackets (7) are spaced apart on the outside of the cooling vertical pipe (6). The cavity between the cooling jacket (7) and the cooling vertical pipe (6) is a cooling cavity. The interior of the cooling cavity is divided into a lower heat absorption chamber (10) and an upper steam chamber (9) by a horizontal partition (8). A cold water inlet (11) is provided at the lower part of the heat absorption chamber (10), and a steam outlet (12) is provided at the top of the steam chamber (9). The cooling vertical pipe is located on the side near the cooling jacket (7). Multiple spiral coils (13) are evenly distributed inside the tube (6). The lower end of the spiral coil (13) is provided with a lower connecting pipe (14) that communicates with the heat absorption chamber (10). The upper end of the spiral coil (13) is provided with an upper connecting pipe (15) that communicates with the steam chamber (9). The yellow phosphorus heat preservation tank (3) is internally installed with a heat transfer pipe (16) that communicates with the phosphorus combustion tower (1). One end of the heat transfer pipe (16) is connected to the steam outlet (12) through a primary steam conveying pipe (17). The other end of the heat transfer pipe (16) is connected to the medium inlet of the air preheater (4) through a secondary steam pipe (18).

2. The thermal energy circulation reaction system for a phosphorus pentoxide production line according to claim 1, characterized in that: There are at least two cooling jackets (7), and multiple cooling jackets (7) are arranged at equal intervals along the vertical direction of the cooling riser (6). The cold water inlet (11) is located on the heat absorption chamber (10) of the bottom cooling jacket (7). The steam chamber (9) of the adjacent lower cooling jacket (7) and the heat absorption chamber (10) of the upper cooling jacket (7) are connected by an intermediate water pipe (19). The steam outlet (12) is located on the steam chamber (9) of each cooling jacket. Multiple steam outlets (12) are connected to the primary steam conveying pipe (17) after being converged by a converging pipe.

3. The thermal energy circulation reaction system for a phosphorus pentoxide production line according to claim 1, characterized in that: A safety valve (20) is installed at the top of the steam chamber (9).

4. The thermal energy circulation reaction system for a phosphorus pentoxide production line according to claim 1, characterized in that: The primary steam delivery pipe (17) passes through the cooling riser (6) from the upper part of the cooling jacket (7) and then connects to the yellow phosphorus heat preservation tank (3). The primary steam delivery pipe (17) located in the phosphorus combustion tower (1) is configured in a serpentine structure.

5. The thermal energy circulation reaction system for a phosphorus pentoxide production line according to claim 1, characterized in that: Multiple heat-conducting fins (24) are evenly distributed on the outer wall of the heat transfer tube (16).

6. The thermal energy circulation reaction system for a phosphorus pentoxide production line according to claim 1, characterized in that: The lower part of the cooling vertical pipe (6) is provided with a smoke guide pipe (21), and the bottom of the cooling vertical pipe (6) is provided with a cone hopper (22) through a flange assembly. The bottom of the cone hopper (22) is provided with a discharge pipe (23), and a discharge valve is provided on the discharge pipe (23).

7. The thermal energy circulation reaction system for a phosphorus pentoxide production line according to claim 1, characterized in that: A thermometer (25) is installed on the top of the yellow phosphorus heat preservation tank (3).

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