Yellow phosphorus electric furnace tail gas three-phase water film cold washing purification process and device

Abstract

The invention discloses a yellow phosphorus electric furnace tail gas three-phase water film cold washing purification process and device, and belongs to the technical field of yellow phosphorus tail gas purification. The invention solves the problem that the yellow phosphorus tail gas is easy to block the tube pass. The yellow phosphorus tail gas is introduced into a cooler which exchanges heat with cooling water to realize cooling, so that yellow phosphorus in the yellow phosphorus tail gas is condensed in a heat exchange channel; and after the purification time reaches the set time, cooling of the cooling water is stopped, cold washing liquid is sprayed into the heat exchange channel, the cold washing liquid replaces the cooling water to conduct heat exchange with the yellow phosphorus tail gas, yellow phosphorus on the innermost side of the heat exchange channel is melted, and meanwhile the cold washing liquid can flush yellow phosphorus condensed in the heat exchange channel. According to the technical scheme, when the yellow phosphorus in the tubular cooler is removed, the removal effect is greatly improved, and the removal rate of the yellow phosphorus in the yellow phosphorus tail gas can be maintained to be 70% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of yellow phosphorus tail gas purification, and in particular relates to a three-phase water film cold washing purification process and a device for yellow phosphorus electric furnace tail gas. Background Art

[0002] Electric furnace is the main equipment for yellow phosphorus production. Qualified phosphate rock, silica and coke are mixed in a certain proportion and added to the electric furnace for reduction reaction at 1300-1500℃. The phosphorus-containing furnace gas is dusted, condensed and refined to obtain finished yellow phosphorus. The by-products slag and ferrophosphorus are discharged from the bottom of the furnace regularly. Therefore, there are strict requirements for the insulation materials, refractory materials and refractory brick structures in the furnace lining.

[0003] The tail gas from the electric furnace generally has a temperature of about 57°C and contains CO, H2, elemental phosphorus P4, sulfur compounds, PH3, dust and other components. Since yellow phosphorus tail gas contains phosphorus and dust, it is easy to adhere to the tube due to the decrease in temperature when it passes through the tube, which, on the one hand, causes a large amount of phosphorus to be lost and cannot be recovered, and on the other hand, the phosphorus attached to the tube will become thicker and thicker over time, thereby blocking the tube. Therefore, it is necessary to provide a technical solution to this problem. Summary of the invention

[0004] Aiming at the problem in the prior art that phosphorus and dust are entrained in yellow phosphorus tail gas, and when the yellow phosphorus tail gas passes through the tube, the phosphorus and dust are easily attached to the tube due to the decrease in temperature, which, on the one hand, causes a large amount of phosphorus to be lost and cannot be recovered, and on the other hand, the phosphorus and dust attached to the tube will become thicker and thicker over time, thereby clogging the tube. The present invention provides a three-phase water film cold washing purification process and device for yellow phosphorus electric furnace tail gas.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A three-phase water film cold washing purification process for yellow phosphorus electric furnace tail gas comprises the following steps:

[0007] Step 1: passing the yellow phosphorus tail gas into a cooler that is cooled by heat exchange with cooling water to reduce the temperature of the yellow phosphorus tail gas, thereby condensing the yellow phosphorus in the yellow phosphorus tail gas in the heat exchange channel, and the purified yellow phosphorus tail gas is discharged from the cooler, and the temperature of the cooling water is maintained at the cooling temperature during the purification process;

[0008] Step 2: When the purification time reaches the set time, stop cooling the cooling water, and detect the temperature of the cooling water in real time. When the cooling water temperature rises to the melting point of yellow phosphorus due to the heat exchange temperature with the yellow phosphorus tail gas, spray a cold washing liquid with a temperature lower than the temperature of the yellow phosphorus tail gas into the heat exchange channel, so that the cold washing liquid and the yellow phosphorus tail gas pass through the heat exchange channel from top to bottom in the same direction. The cold washing liquid replaces the cooling water and continues to perform heat exchange with the subsequent yellow phosphorus tail gas, thereby realizing continuous purification of the yellow phosphorus tail gas. At the same time, the cold washing liquid entering the heat exchange channel forms a water curtain along the side wall of the heat exchange channel, thereby flushing the condensed yellow phosphorus in the heat exchange channel;

[0009] Step 3: After the cold wash liquid is turned on for the set time, the cooling water is cooled until the cooling water temperature drops to the set cooling temperature, and then the cold wash liquid is stopped, so that the cooling water replaces the cold wash liquid and continues to exchange heat with the subsequent yellow phosphorus tail gas;

[0010] Repeat steps 1-3 to achieve continuous purification of yellow phosphorus tail gas.

[0011] After adopting the technical scheme, the present invention firstly exchanges heat with the yellow phosphorus tail gas through the cooling water in the cooler, so that the temperature of the yellow phosphorus tail gas is reduced, so that the yellow phosphorus in the yellow phosphorus tail gas is condensed on the side wall of the heat exchange channel, so as to achieve the effect of separating the phosphorus in the yellow phosphorus tail gas, and avoid condensing in the pipe path and blocking the pipeline in the subsequent process. After a certain thickness of yellow phosphorus is condensed, the cooling of the cooling water is stopped, and the temperature of the cooling water is gradually increased until the melting point of the yellow phosphorus is reached. The cooling water reaching the melting point of the yellow phosphorus is heat-exchanged with the yellow phosphorus adhering to the side wall of the heat exchange channel, so that the yellow phosphorus at the innermost side of the heat exchange channel is melted, so that the connection between the yellow phosphorus and the heat exchange channel is loosened, and even the yellow phosphorus is automatically separated from the side wall of the heat exchange channel under its own gravity. At this time, since the cold washing liquid is also introduced, the introduced cold washing liquid also flushes the yellow phosphorus remaining on the side wall of the heat exchange channel, so that the yellow phosphorus in the heat exchange channel is thoroughly cleaned by heating and water flushing, thereby achieving full recovery of the yellow phosphorus. After the cooling water temperature rises, the cold wash liquid introduced replaces the cooling water to continue heat exchange with the yellow phosphorus tail gas, thereby continuously cooling and purifying the yellow phosphorus tail gas.

[0012] Preferably, in step 2, spraying of the cold wash liquid begins 5-10 seconds after the temperature of the cooling water reaches the melting point of yellow phosphorus.

[0013] After adopting this technical solution, since the sprayed cold washing liquid will also exchange heat with the cooling water, resulting in heat loss of the cooling water, the cold washing liquid is sprayed 5-10 seconds after the cooling water temperature reaches the melting point of yellow phosphorus. This ensures that the heated cooling water has enough time to exchange heat with the yellow phosphorus adhering to the heat exchange channel to ensure the separation effect, while also avoiding affecting the subsequent purification of the yellow phosphorus tail gas.

[0014] Preferably, the temperature of the cold wash liquid is 40-45° C., the pressure is normal pressure, the gas-liquid volume ratio is 140-160:1, and the gas flow rate is 4-6 m / s.

[0015] After adopting this technical solution, the cold washing liquid and the yellow phosphorus electric furnace exhaust gas pass through the water film cold washing heat exchange tubes in the cooler from top to bottom in the same direction, which not only ensures the heat and mass transfer between gas and liquid, but also ensures that the yellow phosphorus and dust dissolved in the cold washing liquid do not clog the water film cold washing heat exchange tubes; the cooling water flows from bottom to top in the shell side of the cooler, ensuring the heat exchange efficiency.

[0016] A three-phase water film cold washing purification device for yellow phosphorus electric furnace tail gas that realizes a three-phase water film cold washing purification process for yellow phosphorus electric furnace tail gas, comprising a shell and tube cooler, the shell and tube cooler comprising an air inlet, an exhaust port, a cooling water inlet and a cooling water outlet, the air inlet is arranged at the upper part of the shell and tube cooler, and the air inlet is connected to an air inlet pipe and a cold washing liquid supply pipe, the exhaust port is arranged at the lower part of the shell and tube cooler, a three-way pipe is arranged at the exhaust port, one end of the three-way pipe is connected to the exhaust port, and the other two ends are respectively connected to a drain pipe and an exhaust pipe, an exhaust pipe is arranged with an induced air fan, and the drain pipe is connected to a cold washing liquid pool.

[0017] Preferably, the cold washing liquid pool is connected to a cold washing nozzle arranged in the cooler through a cold washing liquid supply pipe, and a cold washing liquid pump is arranged on the cold washing liquid supply pipe.

[0018] After adopting this technical solution, the washed yellow phosphorus reaches the cold washing liquid pool from the drainage pipe for precipitation. The yellow phosphorus is precipitated in the lower part of the cold washing liquid pool, and the upper clear liquid side can be retained as the cold washing liquid for the next cold washing to save water.

[0019] Preferably, the cooling water inlet is connected to one end of a cooling water supply pipe, the other end of the cooling water supply pipe is connected to a cooling water outlet, and the cooling water supply pipe is arranged in a circulating water cooling tower.

[0020] After adopting this technical solution, the cooling water is circulated and cooled through the circulating water cooling tower and then recycled to reduce water consumption.

[0021] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0022] 1. The present invention first performs heat exchange with the yellow phosphorus tail gas through the cooling water in the cooler to reduce the temperature of the yellow phosphorus tail gas, so that the yellow phosphorus in the yellow phosphorus tail gas condenses on the side wall of the heat exchange channel, thereby achieving the effect of separating the phosphorus in the yellow phosphorus tail gas and preventing it from condensing in the pipe path and blocking the pipeline in the subsequent process.

[0023] 2. In the present invention, when a certain thickness of yellow phosphorus is condensed, the cooling of the cooling water is stopped, and the temperature of the cooling water is gradually increased until it reaches the melting point of the yellow phosphorus. The cooling water that has reached the melting point of the yellow phosphorus performs heat exchange with the yellow phosphorus adhering to the side wall of the heat exchange channel, so that the yellow phosphorus at the innermost side of the heat exchange channel melts, thereby loosening the connection between the yellow phosphorus and the heat exchange channel, and even automatically detaching from the side wall of the heat exchange channel under its own gravity. At this time, since cold washing liquid is also introduced, the introduced cold washing liquid also flushes the yellow phosphorus remaining on the side wall of the heat exchange channel, thereby achieving thorough cleaning of the yellow phosphorus in the heat exchange channel through heating and water flushing, thereby achieving full recovery of the yellow phosphorus.

[0024] 3. In the present invention, the cold wash liquid introduced after the cooling water temperature rises replaces the cooling water to continue to exchange heat with the yellow phosphorus tail gas, thereby continuously cooling and purifying the yellow phosphorus tail gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Among them, 1-tube cooler, 2-induced air fan, 3-cold wash nozzle, 4-cold wash liquid pump, 5-cold wash liquid pool, 6-circulating water cooling tower. DETAILED DESCRIPTION

[0027] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0028] In the description of the embodiments of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or are the positions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0029] Example 1

[0030] like Figure 1 As shown, a three-phase water film cold washing purification device for tail gas of a yellow phosphorus electric furnace comprises a shell-and-tube cooler 1, wherein the cooler comprises an air inlet, an exhaust port, a cooling water inlet and a cooling water outlet, wherein the air inlet is arranged at the upper part of the cooler, and the air inlet is connected with an air inlet pipe and a cold washing liquid supply pipe, wherein the exhaust port is arranged at the lower part of the cooler, and a three-way pipe is arranged at the exhaust port, wherein one end of the three-way pipe is connected with the exhaust port, and the other two ends are respectively connected with a drain pipe and an exhaust pipe, wherein an exhaust fan 2 is arranged on the exhaust pipe, and the drain pipe is connected with a cold washing liquid pool 5.

[0031] In this embodiment, the cold washing liquid pool 5 is connected to the cold washing nozzle 3 arranged in the tube-in-tube cooler 1 through the cold washing liquid supply pipe, and the cold washing liquid supply pipe is provided with a cold washing liquid pump 4. The washed yellow phosphorus reaches the cold washing liquid pool 5 from the drain pipe for precipitation, and the yellow phosphorus is precipitated in the lower part of the cold washing liquid pool 5, while the upper clear liquid side can be reserved as the cold washing liquid for the next cold washing, so as to save water. The cold washing liquid supply pipe is also connected to a cold washing liquid supply tank, and an electric heater and an electric refrigerator are also arranged in the cold washing liquid supply tank. The temperature of the cold washing liquid in the cold washing liquid supply tank can be regulated by the cooperation of the electric heater and the electric refrigerator. Electric valves and pump bodies are arranged on the pipeline connecting the cold washing liquid supply tank and the cold washing liquid supply pipe and on the pipeline connecting the cold washing liquid pool 5 and the cold washing liquid supply pipe. Temperature sensors are arranged in the cold washing liquid pool 5 and the cold washing liquid supply tank. The temperature in the cold washing liquid pool 5 and the cold washing liquid supply tank is fed back through the temperature sensor. A liquid level meter is also arranged in the cold washing liquid pool 5. When the water amount and temperature in the cold washing liquid pool 5 are not sufficient to meet the use requirements, the amount of cold washing liquid transported from the cold washing liquid pool 5 and the cold washing liquid supply tank to the cold washing liquid supply pipe can be regulated to realize the transportation of quantitative and constant temperature cold washing liquid into the cold washing liquid supply pipe.

[0032] In this embodiment, the cooling water inlet is connected to one end of a cooling water supply pipe, the other end of the cooling water supply pipe is connected to the cooling water outlet, and the cooling water supply pipe is arranged in the circulating water cooling tower 6. The cooling water inlet is connected to one end of a cooling water supply pipe, the other end of the cooling water supply pipe is connected to the cooling water outlet, and the cooling water supply pipe is arranged in the circulating water cooling tower 6.

[0033] The device can be installed at any position in the exhaust gas purification line according to actual purification requirements.

[0034] Example 2

[0035] A three-phase water film cold washing purification process for yellow phosphorus electric furnace tail gas, the process adopts the three-phase water film cold washing purification device for yellow phosphorus electric furnace tail gas of Example 1, and comprises the following steps:

[0036] Step 1: passing the yellow phosphorus tail gas into a shell-and-tube cooler, and continuously passing cooling water at a temperature of 25° C. into the shell-and-tube cooler, so that the yellow phosphorus tail gas and the cooling water perform heat exchange, and the temperature of the yellow phosphorus tail gas is reduced, so that the yellow phosphorus in the yellow phosphorus tail gas is condensed in the heat exchange channel, and the purified yellow phosphorus tail gas is discharged from the cooler and enters the next process. During the purification process, the temperature of the cooling water is maintained at the cooling temperature through the circulating water cooling tower 6;

[0037] Step 2: When the purification time reaches 1 hour, stop cooling the cooling water, and detect the temperature of the cooling water in real time. When the cooling water temperature rises to the melting point of yellow phosphorus 5s after the heat exchange temperature with the yellow phosphorus tail gas, spray a cold washing liquid (water) with a temperature of 40°C into the heat exchange channel, the pressure is normal pressure, the gas-liquid volume ratio is 150:1, and the gas flow rate is 5m / s; the cold washing liquid and the yellow phosphorus tail gas pass through the heat exchange channel from top to bottom in the same direction, and the cold washing liquid replaces the cooling water to continue heat exchange with the subsequent yellow phosphorus tail gas, so as to realize the continuous purification of the yellow phosphorus tail gas. At the same time, the cold washing liquid entering the heat exchange channel forms a water curtain along the side wall of the heat exchange channel, thereby washing the condensed yellow phosphorus in the heat exchange channel;

[0038] Step 3: 10 minutes after the cold wash liquid is started, the circulating water cooling tower 6 is started to cool the cooling water until the cooling water temperature drops to the set cooling temperature, and then the cold wash liquid is stopped, so that the cooling water replaces the cold wash liquid and continues to exchange heat with the subsequent yellow phosphorus tail gas;

[0039] Repeat steps 1-3 to achieve continuous purification of yellow phosphorus tail gas.

[0040] Example 3

[0041] This embodiment is basically the same as Embodiment 2, except that: when the cooling water temperature rises to the melting point of yellow phosphorus due to heat exchange with the yellow phosphorus tail gas 8s later, a cold wash liquid with a temperature lower than the temperature of the yellow phosphorus tail gas is sprayed into the heat exchange channel.

[0042] Example 4

[0043] This embodiment is basically the same as Embodiment 2, except that: after the cooling water temperature rises to the melting point of yellow phosphorus due to heat exchange with the yellow phosphorus tail gas for 10 seconds, a cold wash liquid with a temperature lower than the temperature of the yellow phosphorus tail gas is sprayed into the heat exchange channel.

[0044] Example 5

[0045] This embodiment is basically the same as embodiment 2, except that the temperature of the cold wash liquid is 45°C.

[0046] Example 6

[0047] This embodiment is basically the same as Embodiment 2, except that the cooling water temperature is 30°C.

[0048] Comparative Example 1

[0049] This comparative example is basically the same as Example 2, except that: in this comparative example, the cooling of the cooling water is not stopped, so that the temperature of the cooling water is always maintained at 25°C.

[0050] Comparative Example 2

[0051] This comparative example is basically the same as Example 2, except that: in this comparative example, the cooling of the cooling water is not stopped, so that the temperature of the cooling water is always maintained at 25°C, and the temperature of the cold washing liquid introduced is 25°C.

[0052] Comparative Example 3

[0053] This comparative example is basically the same as Example 2, except that the temperature of the cold wash liquid introduced is 25°C.

[0054] The phosphorus content in the yellow phosphorus tail gas before and after treatment and the residual amount of yellow phosphorus in the heat exchange channel in Examples 2-6 and Comparative Examples 1-3 were detected, wherein the residual amount of yellow phosphorus was detected once the system worked continuously for ten days, the phosphorus content and dust content in the treated yellow phosphorus tail gas were collected by the system for 3 consecutive hours, and then the phosphorus content and dust content in the collected treated yellow phosphorus tail gas were detected, and the phosphorus content and dust content of the tail gas for three consecutive days were obtained by the same method, and the data described in Table 1 were obtained by averaging the three groups of data; the yellow phosphorus tail gas introduced into the system came from the gas collecting tank, and the phosphorus content and dust content in the yellow phosphorus tail gas in the gas collecting tank were detected before the yellow phosphorus tail gas in the gas collecting tank was introduced into the system; the specific results are shown in Table 1:

[0055] Table 1

[0056]

[0057] It can be seen from Table 1 that when the technical solution of the present invention is used to remove yellow phosphorus in the shell-and-tube cooler, not only the removal effect is greatly improved, but also the removal rate of yellow phosphorus in the yellow phosphorus tail gas can be maintained at more than 70%.

[0058] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A three-phase water film cold washing purification process for yellow phosphorus electric furnace tail gas, characterized in that: The following steps are involved: Step 1: passing the yellow phosphorus tail gas into a cooler that is cooled by heat exchange with cooling water to reduce the temperature of the yellow phosphorus tail gas, thereby condensing the yellow phosphorus in the yellow phosphorus tail gas in the heat exchange channel, and the purified yellow phosphorus tail gas is discharged from the cooler, and the temperature of the cooling water is maintained at the cooling temperature during the purification process; Step 2: When the purification time reaches the set time, stop cooling the cooling water, and detect the temperature of the cooling water in real time. When the cooling water temperature rises to the melting point of yellow phosphorus due to the heat exchange temperature with the yellow phosphorus tail gas, spray a cold washing liquid with a temperature lower than the temperature of the yellow phosphorus tail gas into the heat exchange channel, so that the cold washing liquid and the yellow phosphorus tail gas pass through the heat exchange channel from top to bottom in the same direction. The cold washing liquid replaces the cooling water and continues to perform heat exchange with the subsequent yellow phosphorus tail gas, thereby realizing continuous purification of the yellow phosphorus tail gas. At the same time, the cold washing liquid entering the heat exchange channel forms a water curtain along the side wall of the heat exchange channel, thereby flushing the condensed yellow phosphorus in the heat exchange channel; Step 3: After the cold wash liquid is turned on for the set time, the cooling water is cooled until the cooling water temperature drops to the set cooling temperature, and then the cold wash liquid is stopped, so that the cooling water replaces the cold wash liquid and continues to exchange heat with the subsequent yellow phosphorus tail gas; Repeat steps 1-3 to achieve continuous purification of yellow phosphorus tail gas.

2. A three-phase water film cold washing purification process for yellow phosphorus electric furnace tail gas according to claim 1, characterized in that: In step 2, the cold wash liquid is sprayed 5-10 seconds after the temperature of the cooling water reaches the melting point of yellow phosphorus.

3. A three-phase water film cold washing purification process for yellow phosphorus electric furnace tail gas according to claim 1, characterized in that: The temperature of cooling water is 25-30℃.

4. A three-phase water film cold washing purification process for yellow phosphorus electric furnace tail gas according to claim 1, characterized in that: The temperature of the cold wash liquid is 40-45°C, the pressure is normal pressure, the gas-liquid volume ratio is 140-160:1, and the gas flow rate is 4-6 m / s.

5. A three-phase water film cold washing purification device for yellow phosphorus electric furnace tail gas that realizes the three-phase water film cold washing purification process for yellow phosphorus electric furnace tail gas according to any one of claims 2 to 4, characterized in that: The invention comprises a shell-and-tube cooler (1), wherein the shell-and-tube cooler (1) comprises an air inlet, an air outlet, a cooling water inlet and a cooling water outlet, wherein the air inlet is arranged at the upper part of the shell-and-tube cooler (1), and the air inlet is connected to an air inlet pipe and a cold washing liquid supply pipe, wherein the air outlet is arranged at the lower part of the shell-and-tube cooler (1), and a three-way pipe is arranged at the exhaust port, wherein one end of the three-way pipe is connected to the exhaust port, and the other two ends are respectively connected to a liquid discharge pipe and an exhaust pipe, wherein an exhaust fan (2) is arranged on the exhaust pipe, and the liquid discharge pipe is connected to a cold washing liquid pool (5).

6. A three-phase water film cold washing purification device for yellow phosphorus electric furnace tail gas according to claim 5, characterized in that: The cold washing liquid pool (5) is connected to a cold washing nozzle (3) arranged in the cooler via a cold washing liquid supply pipe, and a cold washing liquid pump (4) is arranged on the cold washing liquid supply pipe.

7. The three-phase water film cold washing purification device for yellow phosphorus electric furnace tail gas according to claim 5 is characterized in that: The cooling water inlet is connected to one end of a cooling water supply pipe, the other end of the cooling water supply pipe is connected to a cooling water outlet, and the cooling water supply pipe is arranged in a circulating water cooling tower (6).

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