Styrene plant air cooling anti polymerization system

Abstract

This invention provides an air-cooled anti-polymerization system for a styrene plant, comprising: a quench cooler with a reaction oil / gas inlet pipeline and a reaction oil / gas outlet pipeline at both ends, and a quench water injection pipeline at the top; several nozzles connected to the quench water injection pipeline for injecting quench water into the reaction oil / gas within the quench cooler; at least one regulating valve located on the quench water injection pipeline for regulating the flow rate of the quench water; an air cooler located at the end of the reaction oil / gas outlet pipeline furthest from the quench cooler for further cooling the reaction oil / gas; and a temperature measuring device located on the reaction oil / gas outlet pipeline for online monitoring of the dew point temperature of the reaction oil / gas and the inlet temperature of the air cooler. This invention can prevent polymer blockage of pipelines and equipment caused by substandard air-cooling inlet temperature.

Description

Technical Field

[0001] This utility model relates to the field of air-cooled anti-polymerization technology in styrene production, and in particular to an air-cooled anti-polymerization system for styrene plants. Background Technology

[0002] In styrene plants, the quench cooler sprays quench water, allowing the high-temperature oil and gas to come into direct contact with the cooling medium. This rapidly cools the dehydrogenation reaction oil and gas to near its dew point temperature before it enters the tube side of the air cooler. All heat exchange tubes in the tube side are wetted, rather than exposed to styrene vapor, which would otherwise polymerize within the tube side. However, in actual production, due to various factors such as insufficient water spray flow in the quench cooler, poor atomization, improper installation of thermocouples after the quench cooler, and variations in the dew point temperature of the reaction oil and gas depending on its composition and pressure, the inlet temperature of the air cooler often exceeds the dew point temperature. This can easily lead to polymer blockages in pipes and equipment, causing significant disruption to the stable operation of the plant.

[0003] Therefore, there is an urgent need for an air-cooled anti-polymerization system for styrene plants that can eliminate the drawbacks of existing plants. Utility Model Content

[0004] The purpose of this invention is to provide an air-cooled anti-polymerization system for styrene plants, which aims to solve the technical problem in the prior art where the air-cooling inlet temperature does not meet the standard, causing polymer to clog pipes and equipment and affecting normal production.

[0005] To achieve the above objectives, this utility model provides an air-cooled anti-polymerization system for a styrene plant, comprising:

[0006] The quench cooler has a reaction oil and gas inlet pipeline and a reaction oil and gas outlet pipeline at both ends, and a quench water injection pipeline at the top.

[0007] Several nozzles are connected to the quench water injection pipeline for injecting quench water into the reaction oil and gas in the quencher.

[0008] At least one regulating valve is installed on the quench water injection pipeline to regulate the flow rate of the quench water;

[0009] An air cooler is installed at the end of the reaction oil and gas outlet pipeline away from the quencher, for further cooling of the reaction oil and gas.

[0010] A temperature measuring device is installed on the outlet pipeline of the reaction oil and gas to monitor the dew point temperature of the reaction oil and gas and the inlet temperature of the air cooler online.

[0011] As a further improvement to the above solution, the temperature measuring device includes a first thermometer and a second thermometer;

[0012] The first thermometer is installed on the outlet pipeline of the reaction oil and gas and is axially distanced from the quencher by a first preset value H1, and is used to monitor the dew point temperature of the reaction oil and gas.

[0013] The second thermometer is installed on the reaction oil and gas outlet pipeline and is axially distanced from the quencher by a second preset value H2, and is used to monitor the inlet temperature of the air cooler;

[0014] Wherein, the second preset value H2 is greater than the first preset value H1.

[0015] As a further improvement to the above scheme, both the first thermometer and the second thermometer are thermocouple thermometers.

[0016] As a further improvement to the above solution, an anti-backflow baffle is provided on the reaction oil and gas inlet pipeline near the quencher to prevent water from flowing back into the quencher; preferably, the anti-backflow baffle is about 60 mm high.

[0017] As a further improvement to the above solution, the regulating valve is a pneumatic pressure regulating valve with remote display. Its inlet is connected to the quench water injection pipeline, and its outlet is connected to the nozzle, which is used to regulate the pressure and flow rate of the quench water before it enters the nozzle.

[0018] As a further improvement to the above solution, the plurality of nozzles are four conical nozzles, which are disposed inside the quencher.

[0019] As a further improvement to the above scheme, the atomized water particle size of the conical nozzle is no greater than 60 micrometers.

[0020] As a further improvement to the above scheme, the outlet center axis of the conical nozzle is parallel to the mainstream direction of the reaction oil and gas in the quencher.

[0021] As a further improvement to the above scheme, the atomized water spray range of the conical nozzle does not cover the inner wall of the reaction oil and gas pipeline inside the quencher.

[0022] As a further improvement to the above solution, the air-cooled anti-polymerization system of the styrene plant also includes a controller, and the temperature measuring device and the regulating valve are both electrically connected to the controller;

[0023] The controller is used to receive the air cooler inlet temperature and the reaction oil dew point temperature measured by the temperature measuring device, and adjust the opening of the regulating valve according to the difference between the two.

[0024] Because this utility model adopts the above technical solutions, the beneficial effects of this application are as follows:

[0025] This invention provides an air-cooled anti-polymerization system for a styrene plant. By setting a reasonable number of quench water nozzles, quench water is sprayed in a mist-like manner. The reaction oil and gas exchange heat directly with the quench water, removing heat. A regulating valve installed on the quench water injection pipeline can adjust the quench water flow rate according to actual needs. For example, when the temperature measuring device detects that the air-cooled inlet temperature is too high, the opening of the regulating valve is increased to increase the quench water spray volume and enhance the cooling effect; when the temperature is too low, the opening is decreased to avoid over-cooling, thereby achieving stable control of the air-cooled inlet temperature and reducing the risk of polymer precipitation caused by temperature fluctuations. The controllable adjustment of the quench water flow rate can effectively reduce and stabilize the air-cooled inlet temperature, preventing polymer formation due to substandard temperature. Simultaneously, the online monitoring of the temperature measuring device provides real-time data for temperature control, maintaining the air-cooled inlet temperature 0-3°C above the dew point temperature, further reducing the risk of high-temperature styrene polymerization and enabling long-term operation of the plant. The air cooler further distributes the cooling load, ensuring efficient system operation, thereby reducing the risk of pipeline and equipment blockage and guaranteeing normal production of the styrene plant. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of an air-cooled anti-polymerization system for a styrene plant disclosed in this utility model;

[0028] Figure label:

[0029] 1. Quencher; 2. Reactor oil and gas inlet pipeline; 3. Reactor oil and gas outlet pipeline; 4. Quencher water injection pipeline; 5. Nozzle; 6. Regulating valve; 7. Air cooler; 8. First thermometer; 9. Second thermometer; 10. Anti-backflow baffle.

[0030] The purpose, features, and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that all directional indicators (such as up, down, etc.) in the embodiments of this utility model are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0033] Furthermore, in this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0034] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of a person skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0035] See Figure 1 This utility model provides an air-cooled anti-polymerization system for a styrene plant. The system includes a quench cooler 1, a nozzle 5, a regulating valve 6, an air cooler 7, and a temperature measuring device, wherein:

[0036] The quench cooler 1 is a horizontally positioned cylindrical heat exchange container. Its left end is fixedly connected to the reaction oil and gas inlet pipeline 2 to receive the high-temperature reaction oil and gas transported from the upstream unit; its right end is fixedly connected to the reaction oil and gas outlet pipeline 3 to output the initially cooled oil and gas; the top of the quench cooler 1 is connected to the quench water injection pipeline 4 by welding to transport low-temperature quench water.

[0037] Several nozzles 5 (four in this embodiment) are evenly distributed around the circumference of the quencher 1. The lower end of each nozzle 5 is connected to the quench water injection pipeline 4, and the upper end extends into the interior of the quencher 1 and faces the direction of reaction oil and gas flow, so as to spray quench water into the reaction oil and gas in an atomized form.

[0038] At least one regulating valve 6 is installed on the quench water injection pipeline 4, located between the quench cooler 1 and the quench water storage tank, and its valve stem is connected to the actuator to adjust the quench water flow rate according to the control signal.

[0039] Air cooler 7, preferably a shell-and-tube heat exchanger, is located on the right side of the reaction oil and gas outlet pipeline 3, that is, downstream of the quench cooler 1. It is connected to the reaction oil and gas outlet pipeline 3 through a flange and is used to further cool the oil and gas that has been initially cooled by the quench cooler 1 with air, so as to reduce the oil and gas temperature to the range required by the subsequent processing unit.

[0040] The temperature measuring device, including a first thermometer 8 and a second thermometer 9, is fixed to the outer wall of the reaction oil and gas outlet pipeline 3.

[0041] The first thermometer 8 is located downstream of the connection between the outlet pipeline 3 of the reaction oil and gas and the outlet pipeline of the quencher 1. The axial distance from the right end face of the quencher 1 is a first preset value H1 (preferably, in this embodiment, the value of H1 is 3-5m). It is used to monitor the dew point temperature of the reaction oil and gas after it leaves the quencher 1 in real time, that is, the gas phase temperature at which the easily polymerizable components begin to condense.

[0042] The second thermometer 9 is located to the right of the first thermometer 8, and the axial distance from the right end face of the quencher 1 is a second preset value H2 (preferably, in this embodiment, the value range of H2 is approximately 13m, and H2>H1), used to monitor the actual temperature of the reaction oil and gas at the inlet of the air cooler 7 in real time.

[0043] During system operation, high-temperature reaction oil and gas from the upstream unit enters the quench cooler 1 via the inlet pipeline. Low-temperature water in the quench water injection pipeline 4 is atomized through nozzle 5, making full contact with the reaction oil and gas and rapidly reducing its temperature due to heat absorption from the phase change. The regulating valve 6 dynamically adjusts its opening based on the temperature signal from the temperature measuring device, controlling the quench water flow to stabilize the quenching effect. Subsequently, the reaction oil and gas enters the air cooler 7 via the outlet pipeline, where it is further cooled to the process temperature by the external airflow, and finally delivered to the downstream unit. The temperature measuring device obtains the dew point temperature of the quenched oil and gas and the air cooler inlet temperature via the first thermometer 8 and the second thermometer 9, respectively, providing real-time data support for the control of the regulating valve 6.

[0044] This invention effectively solves the problem of polymer blockage caused by substandard air-cooled inlet temperature in existing technologies through the synergistic effect of various technical features. Specifically, the quench cooler 1 provides initial cooling space for the reaction oil and gas, and the nozzle 5 uniformly sprays atomized quench water along the axial direction, increasing the contact area between water and oil and gas. The quench water undergoes phase change and absorbs heat, quickly removing heat from the oil and gas, directly reducing the oil and gas temperature before the air cooler inlet, thus inhibiting polymer formation conditions from the source. The regulating valve 6 is installed on the quench water injection pipeline 4 and can adjust its opening in real time according to the temperature signal fed back by the temperature measuring device. For example, when the second thermometer 9 detects that the air cooler inlet temperature is too high, the opening of the regulating valve 6 is increased to increase the quench water injection volume and enhance cooling; when the temperature is too low, the regulating valve 6 is opened to increase the quench water injection volume and enhance cooling. Reducing the opening degree avoids excessive cooling, thereby stabilizing the air cooler inlet temperature and reducing the risk of polymer precipitation caused by temperature fluctuations. The first thermometer 8 is close to the quench cooler 1 and can quickly capture the temperature of the oil and gas just leaving the quench cooler 1 (reflecting the quenching effect). The second thermometer 9 is far from the quench cooler 1, and H2>H1, which can reflect the uniform temperature of the oil and gas in the outlet pipeline, serving as the true temperature of the air cooler inlet. The difference between the two provides a more comprehensive control basis for the regulating valve 6, avoiding polymer formation due to substandard temperature and enabling long-term operation of the unit. The air cooler 7 further distributes the cooling load, ensuring efficient system operation, thereby reducing the risk of pipeline and equipment blockage and ensuring normal production of the styrene unit.

[0045] In a preferred embodiment, both the first thermometer 8 and the second thermometer 9 are thermocouple thermometers, specifically type K thermocouples. During installation, the measuring end of the thermocouple is fixed to the outer wall of the reaction oil and gas outlet pipeline 3 through a stainless steel protective sleeve, and the signal transmission end of the thermocouple is led out through a compensating wire and connected to the system's temperature acquisition module. The temperature signal is converted into an electrical signal and transmitted to the controller for real-time calculation of the difference between the dew point temperature and the air cooler inlet temperature. The application of thermocouple thermometers enables the temperature measuring device to operate stably in the high-temperature, highly corrosive, and highly interfering environment of the styrene plant, providing more reliable temperature data support for the system's efficient anti-polymerization.

[0046] In a preferred embodiment, an anti-backflow baffle 10 is installed on the reaction oil and gas inlet pipeline 2 near the quench cooler 1 to prevent water from flowing back into the quench cooler 1. Specifically, the anti-backflow baffle 10 is located at the end of the reaction oil and gas inlet pipeline 2, i.e., near the inlet flange of the quench cooler 1. Preferably, it is installed on the inner wall of the pipeline at a distance of 50mm to 70mm from the end face of the inlet flange of the quench cooler 1. The height of the baffle is preferably 60mm, which is determined based on the nominal diameter of the reaction oil and gas inlet pipeline 2 and the droplet carrying characteristics after the quench water is sprayed. After the reaction oil and gas are cooled in the quench cooler 1, some of the unevaporated quench water may flow back towards the inlet pipeline with the oil and gas. The anti-backflow baffle 10 can effectively prevent the liquid from flowing back into the quench cooler 1 by physically blocking it, thus avoiding corrosion or scaling of the pipes, nozzles 5, and other components in the quench cooler 1 due to long-term contact with water.

[0047] In a preferred embodiment, the regulating valve 6 is a pneumatic pressure regulating valve 6 with remote display, and its structure includes a valve body, a pneumatic diaphragm actuator, and a remote display module. Specifically, the valve body inlet is connected to the upstream section of the quench water injection pipeline 4 through a flange, and the outlet is connected to the water inlet of the nozzle 5 through a flange, forming a spray path of "quench water main → regulating valve 6 → nozzle 5".

[0048] The remote display module, integrated on the top of the valve body, includes pressure and flow sensors. It collects real-time data on inlet and outlet pressures, as well as the actual flow rate of the quench water, and transmits this data to the unit controller via analog signals. The controller simultaneously displays parameters such as "current pressure," "current flow rate," and "set value" on the operator's station screen. During system operation, when the temperature sensor reports a deviation of the air-cooled inlet temperature from the set value (e.g., too high), the controller calculates the required quench water flow rate based on the temperature difference and outputs a control signal to the pneumatic diaphragm actuator. This actuator drives the valve stem to adjust the valve core opening: increasing the opening to increase flow and enhance cooling when the temperature is too high, and decreasing the opening to reduce flow and prevent over-cooling when the temperature is too low. Simultaneously, the remote display module provides real-time feedback on the operating status of the regulating valve 6, facilitating remote monitoring and troubleshooting by operators. The pneumatic pressure regulating valve 6 with remote display, through its precise control, rapid response, and remote monitoring characteristics, is highly compatible with the high-temperature, high-pressure, and multi-interference operating conditions of the styrene unit, effectively improving the operational reliability and automation level of the air-cooled anti-polymerization system.

[0049] In a preferred embodiment, the plurality of nozzles 5 consists of four conical nozzles 5, evenly distributed around the circumference of the quencher 1, and fixed to the inner top wall of the quencher 1 by threaded connection or welding. Their inlet ends are connected to the quench water injection pipeline 4. Preferably, each conical nozzle 5 has a cone angle of 60°~90°, a nozzle orifice diameter of 0.5mm~1.0mm, and a working pressure of 0.3MPa~0.5MPa. It breaks the quench water into atomized droplets through pressure atomization. The even circumferential distribution of the four nozzles 5 ensures that the quench water is evenly sprayed to all areas of the cross-section of the quencher 1, avoiding localized cooling blind spots caused by a single nozzle 5 or a small number of nozzles 5. This ensures a uniform temperature drop of the reaction oil and gas within the quencher 1, reducing the risk of polymer formation due to localized overheating.

[0050] The atomized water particle size of the conical nozzle 5 is no greater than 60 micrometers. This is achieved by controlling the nozzle 5 orifice diameter, working pressure, and liquid viscosity. The smaller orifice diameter and appropriate pressure allow the water droplets to be fully broken up in the high-speed airflow, ensuring that the particle size meets the standard. The specific surface area of ​​the small-particle-diameter atomized water is significantly increased, resulting in a larger contact area with the reacting oil and gas, higher phase change heat absorption efficiency, and rapid reduction of oil and gas temperature, thus inhibiting polymer precipitation from the source.

[0051] The outlet center axis of the conical nozzle 5 is parallel to the mainstream direction of the reaction oil and gas in the quench cooler 1. This is achieved by adjusting the installation angle of the nozzle 5, so that the direction of atomized water spray is consistent with the direction of oil and gas flow. With the outlet axis of the nozzle 5 parallel to the mainstream direction of oil and gas, the direction of atomized water spray is consistent with the direction of oil and gas flow. Water droplets are less likely to splash onto the inner wall of the pipe due to turbulent reverse movement during the flow of oil and gas. At the same time, the parallel water flow can form a stable gas-water mixture with the oil and gas, reducing the residence time of water droplets in the quench cooler 1 and avoiding secondary evaporation of water and temperature rebound caused by prolonged retention.

[0052] The atomized water spray range of the conical nozzle 5 (a semi-conical area centered on the nozzle 5 outlet, covered by water droplets with a particle size of 50μm) does not cover the inner wall of the reaction oil and gas pipeline inside the quench cooler 1, ensuring that the atomized water is concentrated in the mainstream oil and gas area and avoiding direct impact on the pipe wall. By avoiding the inner wall of the pipeline, the atomized water spray range directly reduces the impact of water droplets on the pipe wall, preventing thinning of the pipe wall or cracking of the weld due to long-term impact. Simultaneously, it reduces the possibility of water droplets adhering to the pipe wall surface, lowering the risk of localized corrosion caused by water evaporation and extending the service life of the pipeline inside the quench cooler 1.

[0053] In a preferred embodiment, the air-cooled anti-polymerization system of the styrene plant further includes a controller, and the temperature measuring device and the regulating valve 6 are both electrically connected to the controller;

[0054] The controller is used to receive the inlet temperature of the air cooler 7 and the dew point temperature of the reaction oil gas measured by the temperature measuring device, and adjust the opening of the regulating valve 6 according to the difference between the two.

[0055] Specifically, the controller's control logic is as follows:

[0056] Data acquisition: Real-time reading of the dew point temperature T1 of the first thermometer 8 and the air cooler inlet temperature T2 of the second thermometer 9, and calculation of the temperature difference ΔT = T2 - T1;

[0057] Deviation Judgment: When T2-T1 > 3℃, it indicates insufficient cooling of quench cooler 1 and excessively high inlet temperature of the air cooler, posing a risk of polymerization. In this case, it is necessary to increase the opening signal of quench water pressure regulating valve 6 to increase quench water pressure, increase water spray volume, enhance cooling effect, and lower T2. When T2-T1 < 0℃, it indicates excessive cooling of quench cooler 1, which not only increases the risk of equipment corrosion but also wastes energy. In this case, it is necessary to decrease the opening signal of quench water pressure regulating valve 6 to reduce quench water pressure, decrease water spray volume, and raise T2. When 0℃ ≤ T2-T1 ≤ 3℃, it indicates that the temperature is within the ideal range, and the current quench water pressure should be maintained unchanged.

[0058] Regulation execution: After receiving the output signal from the controller, the regulating valve 6 dynamically adjusts the valve core opening to control the quench water flow rate; when the temperature is too high, the opening is increased to increase the flow rate and enhance cooling; when the temperature is too low, the opening is decreased to reduce the flow rate and avoid over-cooling, ultimately ensuring that 0℃ ≤ T2-T1 ≤ 3℃, indicating that the temperature is within the ideal range, and maintaining the current quench water pressure unchanged.

[0059] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. An air-cooled anti-polymerization system for a styrene plant, characterized in that, include: The quench cooler has a reaction oil and gas inlet pipeline and a reaction oil and gas outlet pipeline at both ends, and a quench water injection pipeline at the top. Several nozzles are connected to the quench water injection pipeline for injecting quench water into the reaction oil and gas in the quencher. At least one regulating valve is installed on the quench water injection pipeline to regulate the flow rate of the quench water; An air cooler is installed at the end of the reaction oil and gas outlet pipeline away from the quencher, for further cooling of the reaction oil and gas. A temperature measuring device is installed on the outlet pipeline of the reaction oil and gas to monitor the dew point temperature of the reaction oil and gas and the inlet temperature of the air cooler online.

2. The air-cooled anti-polymerization system for a styrene plant according to claim 1, characterized in that, The temperature measuring device includes a first thermometer and a second thermometer; The first thermometer is installed on the outlet pipeline of the reaction oil and gas and the axial distance from the quencher is a first preset value, and is used to monitor the dew point temperature of the reaction oil and gas. The second thermometer is installed on the reaction oil and gas outlet pipeline and is axially distanced from the quencher at a second preset value, and is used to monitor the inlet temperature of the air cooler; Wherein, the second preset value is greater than the first preset value.

3. The air-cooled anti-polymerization system for a styrene plant according to claim 2, characterized in that, Both the first thermometer and the second thermometer are thermocouple thermometers.

4. A styrene plant air-cooled anti-polymerization system according to any one of claims 1-3, characterized in that, An anti-backflow baffle is installed on the inlet pipeline of the reaction oil and gas near the quencher to prevent water from flowing back into the quencher.

5. A styrene plant air-cooled anti-polymerization system according to any one of claims 1-3, characterized in that, The regulating valve is a pneumatic pressure regulating valve with remote display. Its inlet is connected to the quench water injection pipeline, and its outlet is connected to the nozzle. It is used to regulate the pressure and flow rate of the quench water before it enters the nozzle.

6. A styrene plant air-cooled anti-polymerization system according to any one of claims 1-3, characterized in that, The plurality of nozzles are four conical nozzles, which are located inside the quencher.

7. The air-cooled anti-polymerization system for a styrene plant according to claim 6, characterized in that, The atomized water particle size of the conical nozzle is no greater than 60 micrometers.

8. The air-cooled anti-polymerization system for a styrene plant according to claim 6, characterized in that, The central axis of the outlet of the conical nozzle is parallel to the mainstream direction of the reaction oil and gas in the quencher.

9. A styrene plant air-cooled anti-polymerization system according to claim 6, characterized in that, The atomized water spray range of the conical nozzle does not cover the inner wall of the reaction oil and gas pipeline inside the quencher.

10. A styrene plant air-cooled anti-polymerization system according to any one of claims 1-3, characterized in that, It also includes a controller, and both the temperature measuring device and the regulating valve are electrically connected to the controller; The controller is used to receive the air cooler inlet temperature and the reaction oil dew point temperature measured by the temperature measuring device, and adjust the opening of the regulating valve according to the difference between the two.

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