Melamine pulse intermittent purging and separating device

Abstract

The utility model relates to a melamine pulse batch-type purging separation device, the output end is connected with a pipeline system, the device comprises a branch air pipe, a flow deflector is arranged at the connecting position of the pipeline system and the branch air pipe, the flow deflector wraps the outlet of the branch air pipe and forms a flow guide cavity, the flow deflector comprises an arc-shaped part and a straight line part, and the arc-shaped part is connected with the straight line part. And the straight line part is parallel to the flow direction of gas in the pipeline system. According to the utility model, the valve is intermittently purged through the branch air pipe pulse, so that the interior of the valve body is ensured to be clean, and the valve acts freely and is closed tightly; meanwhile, the flow deflectors are arranged, the flow direction of gas can be changed, the gas is forced to be parallel to the linear part, and therefore the gas flowing out of the branch gas pipes and the gas flow direction in the pipeline system are the same, and the pulse effect of compressed gas can be reserved.

Description

Technical Field

[0001] This utility model belongs to the field of melamine processing technology, and specifically relates to a melamine pulse intermittent purging and separation device. Background Technology

[0002] The current melamine production process involves liquid urine entering the reactor and reacting with a catalyst at a gauge pressure of 0.07–0.12 MPa and a high temperature of 390°C to produce melamine. After the reaction, the gaseous products and byproducts are transported by a carrier gas through primary and secondary cyclone separators to recover most of the catalyst particles entrained in the gas stream. The gas then enters the hot gas cooler tubes, where it circulates and exchanges heat with the Dowsen liquid outside the tubes. The temperature drops from 390°C to 340°C, causing high-boiling-point byproducts such as melamine and melamine to crystallize and precipitate. The heat released by the reaction gases is carried by the Dowsen liquid to the Dowsen heat exchanger, generating saturated steam at 1.27 MPa. The gas-solid mixture exiting the hot gas cooler enters the primary separator and hot gas filter to remove solid impurities such as catalysts and high-boiling-point byproducts from the gas stream. Two units each of the hot gas cooler, primary separator, and hot gas filter are installed. When the filter resistance rises to a specified value, the system can switch to another standby set of hot gas cooler, primary separator, and hot gas filter to continue operation. Two pairs of electric valves are installed at the inlet of the hot gas cooler and the outlet of the filter. Currently, unit switching must be performed while the unit is shut down, which takes nearly a day to restart normal production. To change this situation, the unit is modified by installing four DN700 electric valves at the two pairs of DN900 flanges from the inlet of the hot gas cooler and the outlet of the filter to the inlet of the gas collecting pipe. This enables online switching of the unit, improving its effective production time and extending its production cycle.

[0003] However, the gas in the pipeline carries catalyst particles and solid impurities from cooling crystallization, which can cause the valve to become unresponsive or not close properly. Utility Model Content

[0004] This invention addresses the problem in existing technologies where gas entrainment of catalyst particles and cooling crystalline solid impurities in pipelines causes valves to become unresponsive or fail to close properly. It provides a melamine pulse intermittent purging separation device, the specific technical solution of which is as follows:

[0005] This application provides a melamine pulse intermittent purging separation device, the output end of which is connected to a pipeline system, including a bronchus. A guide vane is provided at the junction of the pipeline system and the bronchus. The guide vane covers the outlet of the bronchus and forms a guide cavity. The guide vane includes an arc-shaped part and a straight part. The straight part is parallel to the gas flow direction in the pipeline system.

[0006] As a further technical solution of this utility model, a sealing plate is provided inside the flow guiding cavity. The hinged end of the sealing plate is rotatably connected to the inner wall of the top of the flow guiding plate. The free end of the sealing plate hangs down naturally under the influence of gravity and blocks the flow guiding cavity.

[0007] As a further technical solution of this utility model, a baffle is provided in the flow guiding cavity. In the blocking state, the baffle abuts against the sealing plate and forms a sealing surface.

[0008] As a further technical solution of this utility model, the pipeline system is provided with two sets of pipeline systems in parallel. Each set of pipeline systems is connected in series along the gas flow direction, including valve body one, hot gas cooler, primary separator, hot gas filter and valve body two. The two sets of branch pipes are respectively located in front of valve body one and valve body two. The input ends of the two sets of branch pipes are merged and connected, and a main gas pipe is connected at the connection point. The input end of the main gas pipe is connected to an external gas source.

[0009] The beneficial effects of this utility model are as follows:

[0010] (1) In this application, the valve body is kept clean by intermittent bronchial pulse purging, the valve can move freely and close tightly.

[0011] (2) In this application, a guide vane is also provided, which can change the gas flow direction and force the gas to be parallel to the straight section, so that the gas flowing out of the bronchus is in the same direction as the airflow in the pipeline system, and the pulse effect of compressed gas can be retained.

[0012] (3) In this application, a sealing plate and a baffle are provided. In the purging state, the gas pushes open the sealing plate and enters the pipeline system. In the non-purging state, the sealing plate is naturally drooping and blocking the flow cavity due to gravity, so as to avoid the backflow of gas in the pipeline system. Attached Figure Description

[0013] Figure 1 A schematic diagram of the overall structure of the melamine pulse intermittent purging separation device is shown;

[0014] Figure 2 A schematic diagram of the specific structure of the melamine pulse intermittent purging separation device is shown.

[0015] Legend:

[0016] 110. Gas collection tank one; 120. Gas collection tank two; 200. Piping system; 210. Valve body one; 220. Hot gas cooler; 230. Primary separator; 240. Hot gas filter; 250. Valve body two; 310. Branch pipe; 320. Main pipe; 330. Guide vane; 331. Arc-shaped section; 332. Straight section; 340. Guide cavity; 350. Sealing plate; 360. Baffle. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0018] Figure 1 A schematic diagram of the melamine pulse intermittent purging separation device in use is shown. Figure 1 The system includes a gas collecting tank 110 and a gas collecting tank 220. Two sets of pipeline systems 200 are arranged in parallel between the gas collecting tank 110 and the gas collecting tank 220. The pipeline system 200 is connected in series along the gas flow direction, including a valve body 1 210, a hot gas cooler 220, a primary separator 230, a hot gas filter 240, and a valve body 250. The gas enters the hot gas cooler tube and circulates with the Dowden liquid outside the tube for heat exchange. The temperature drops from 390°C to 340°C in the guide cavity. High-boiling-point byproducts such as melamine and melamine crystallize out. The heat released by the reaction gas is carried by the Dowden liquid to the Dowden heat exchanger to generate saturated steam at 1.27 MPa. The gas-solid mixture exiting the hot gas cooler enters the primary separator and hot gas filter to remove solid impurities such as catalysts and high-boiling-point byproducts from the gas stream. Two units each of the hot gas cooler, primary separator, and hot gas filter are installed. When the filter resistance rises to a specified value, the system can switch to another standby set of hot gas cooler, primary separator, and hot gas filter to continue operation. Two pairs of electric valves are installed at the inlet of the hot gas cooler and the outlet of the filter. Currently, unit switching must be performed while the unit is shut down, which takes nearly a day to restart normal production. To change this situation, the unit is modified by installing four DN700 electric valves at the two pairs of DN900 flanges from the inlet of the hot gas cooler and the outlet of the filter to the inlet of the gas collecting pipe. This enables online switching of the unit, improving its effective production time and extending its production cycle.

[0019] However, the gas in the pipeline carries catalyst particles and solid impurities from cooling crystallization, which can cause the valve to become unresponsive or not close properly.

[0020] The melamine pulse intermittent purging separation device includes two sets of branch pipes 310 connected to the pipeline system 200. The two sets of branch pipes 310 are respectively located in front of valve body 1 210 and valve body 250. The input ends of the two sets of branch pipes 310 are connected together, and a main air pipe 320 is connected at the connection point. An external air source is connected to the input end of the main air pipe 320. Compressed gas generated by the compressed air source enters the pipeline system 200 through the branch pipes 310 via the main air pipe 320 and purges valve body 1 210 and valve body 250. The valves are purged intermittently in pulses, ensuring that the valve body is clean, the valve moves freely, and closes tightly.

[0021] However, since the bronchus 310 and the pipeline system 200 are at an angle, and the pipeline system 200 itself has airflow, when the compressed gas in the bronchus 310 enters the pipeline system 200 at another angle, the two streams of gas with different directions will interfere with each other, resulting in poor pulse effect.

[0022] Figure 2 A schematic diagram of the specific structure of the melamine pulse intermittent purging separation device is shown; Figure 2 In the pipeline system 200, a guide vane 330 is provided at the junction with the bronchus 310. The guide vane 330 covers the outlet of the bronchus 310 and forms a guide cavity 340. The guide vane 330 includes an arc-shaped part 331 and a straight part 332. The straight part 332 is parallel to the gas flow direction in the pipeline system 200. The gas first flows into the guide cavity 340 through the bronchus 310. The arc-shaped part 331 changes the gas flow direction, forcing the gas to be parallel to the straight part 332. Thus, the gas flowing out of the bronchus 310 is in the same direction as the airflow in the pipeline system 200, which can retain the pulse effect of compressed gas.

[0023] Since the pulse is often an intermittent purging process, when the flow guide cavity 340 is normally open in the non-purging state, it can easily cause the gas in the pipeline system 200 to flow back into the bronchus 310.

[0024] A sealing plate 350 is provided inside the flow guiding cavity 340. The hinged end of the sealing plate 350 is rotatably connected to the inner wall of the top of the flow guiding plate 330. The free end of the sealing plate 350 hangs down naturally under the influence of gravity and blocks the flow guiding cavity 340. In the purging state, the gas pushes open the sealing plate 350 and enters the pipeline system 200. In the non-purging state, the sealing plate 350 hangs down naturally under the influence of gravity and blocks the flow guiding cavity 340 to prevent the gas from flowing back into the pipeline system 200. A baffle 360 ​​is provided inside the flow guiding cavity 340. In the blocking state, the baffle 360 ​​abuts against the sealing plate 350 and forms a sealing surface. That is, the end faces of the baffle 360 ​​and the sealing plate 350 that come into contact match, and when they come into contact, they can form a sealing surface to ensure the sealing effect of the flow guiding cavity 340.

[0025] The above embodiments are only used to illustrate the technical solution of this utility model, and are not intended to limit it.

Claims

1. A melamine pulse intermittent purging separation device, the output end of which is connected to a pipeline system (200), characterized in that, The system includes a bronchus (310) that intermittently blows out compressed gas. A guide vane (330) is provided at the junction of the bronchus (310) and the pipeline system (200). The guide vane (330) covers the outlet of the bronchus (310) and forms a guide cavity (340). The guide vane (330) includes an arc-shaped part (331) and a straight part (332). The straight part (332) is parallel to the gas flow direction in the pipeline system (200).

2. The melamine pulse intermittent purging separation device according to claim 1, characterized in that, A sealing plate (350) is provided inside the flow guiding cavity (340). The hinged end of the sealing plate (350) is rotatably connected to the inner wall of the top of the flow guiding plate (330). The free end of the sealing plate (350) hangs down naturally under the influence of gravity and blocks the flow guiding cavity (340).

3. The melamine pulse intermittent purging separation device according to claim 2, characterized in that, A baffle plate (360) is provided inside the flow guide cavity (340). In the blocking state, the baffle plate (360) abuts against the sealing plate (350) and forms a sealing surface.

4. The melamine pulse intermittent purging separation device according to claim 3, characterized in that, The pipeline system (200) is provided with two sets of pipeline systems (200) arranged in parallel. Each set of pipeline systems (200) is connected in series along the gas flow direction with valve body one (210), hot gas cooler (220), primary separator (230), hot gas filter (240) and valve body two (250). The two sets of branch pipes (310) are respectively in front of valve body one (210) and valve body two (250). The input ends of the two sets of branch pipes (310) are connected together, and the connection point is connected to a main gas pipe (320). The input end of the main gas pipe (320) is connected to an external gas source.

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