Cooling PP Reactor The standard configuration is 10 MPa, or 100 atmospheres; however, we can customize cooling PP reactors to operate at 20 MPa or 30 MPa. As for selecting the appropriate pressure rating for your reactor, this should be determined based on your specific experimental conditions. The higher the pressure, the less desirable it generally is. Each cooling PP reactor is equipped with a safety valve and an alarm control system, so you needn't worry about safety issues. On the other hand, the greater the external pressure, the thicker and heavier the reactor vessel walls become. Moreover, as the pressure increases, the corresponding pressure measurement range also expands, making digital pressure gauges less accurate and more prone to measurement errors. If you require highly precise pressure readings under high pressure, we recommend opting for a digital pressure gauge. However, digital pressure gauges have larger dials, which may not look as aesthetically pleasing, and they tend to be more expensive than traditional pointer-type pressure gauges. So, let’s now take a closer look at the key points you should pay attention to when operating a cooling PP reactor!

　　What should be noted when heating and cooling a cooled PP reactor?

　　During the operation of a cooling PP reactor, exercise caution when performing heating and cooling procedures. It is strictly prohibited to subject the reactor to rapid cooling or rapid heating, as excessively high temperatures could cause the reactor vessel to crack or become damaged.

　　After the operation is complete, you can either cool it with water (for exothermic reactions) or allow it to air-cool. To achieve a tight seal on the needle valve, simply turn the needle valve gently until the sealing surface makes close contact—this will provide an excellent seal. Please avoid applying excessive force, as this could damage the sealing surface.

　　After the reaction is complete, begin by cooling down to release the high-pressure gas inside the reactor, reducing the pressure to atmospheric level. Then, carefully and evenly loosen and remove the bolts in a symmetrical manner. When removing the lid, pay special attention to protecting the sealing surface.

　　At the end of each operation, please remove any residues from the reactor body and reactor lid. All sealing surfaces of the PP reactor must be regularly cleaned and dried after cooling. Do not use hard objects or rough, soft materials for cleaning.

　　When disassembling the agitator for cleaning, the heat-transfer jacket of a cooling PP reactor—typically made of ordinary carbon steel—is a sealed space formed outside the reactor vessel body. It is simple and convenient to use. The jacket is equipped with inlets and outlets for steam, cooling water, or other heating/cooling media. When the heating medium is steam, the inlet pipe is located near the upper end of the jacket, and the condensate is discharged from the bottom. If the heat-transfer medium is a liquid, the inlet pipe is positioned at the bottom, allowing the liquid to enter from the bottom and flow out from the top, thereby ensuring that the entire jacket space is completely filled with the heat-transfer medium.

　　For large-scale vessels, to achieve better heat transfer performance, spiral baffles can be installed in the jacket space. These baffles reduce the flow area of the fluid within the jacket, increase the fluid’s flow velocity, and prevent short-circuiting; however, they also result in a more complex structure. When the vessel diameter is large or the pressure of the heat-transfer medium used is relatively high, a semi-circular spiral tube or a welded structure made of spiral angle steel is often employed instead of the conventional jacket-type design. Such a design not only increases the flow velocity of the heat-transfer medium and improves heat transfer efficiency but also enhances the external pressure resistance and rigidity of the reactor. To further boost heat transfer efficiency, a non-condensable gas vent is provided at the upper end of the jacket. The gap between the jacket and the vessel shell varies depending on the nominal diameter of the vessel, typically ranging from 25 to 100 mm. The height of the jacket is determined by the required heat transfer area, which in turn is dictated by process requirements. However, it should be noted that the jacket height generally should not be lower than the liquid level inside the vessel. To ensure adequate heat transfer, the liquid level should be maintained about 50 to 100 mm above the bottom of the vessel. As the volume of the reaction equipment increases, heat transfer issues become more pronounced, and simply using a jacket becomes insufficient. Therefore, additional heat-transfer plates are often installed inside the reactor. These heat-transfer plates not only increase the heat transfer area and effectively dissipate heat but also enhance the mixing effect, helping to break up vortices and control the flow pattern. There are many different types of such plates, with commonly used ones including D-shaped baffle plates, finger-type baffles, sleeve-type baffles, annular-tube baffles, and elliptical-tube baffles. The heat transfer coefficient of these baffles is significantly higher than that of the jacket itself. This is because the cooling water flows at a higher velocity, the tube walls are thinner, and the material supply coefficient on the baffle surface is also greater, resulting in a higher overall heat transfer coefficient. However, when using these heat-transfer baffles, structural considerations and cleaning requirements must be taken into account: the baffles must be completely submerged below the liquid level, as the gas-liquid interface is a region prone to fouling.

　　General Process Specifications for Mechanical Machining of Cooling PP Reactors:

　　1. When operating the reactor, carefully review all instructions provided in the drawings and process documents, ensuring that the process documents remain clean and complete. Strictly adhere to the design drawings (process procedures and technical requirements) when machining parts, and do not make any arbitrary modifications.

　　2. Operators shall, according to process requirements, check the borrowed measuring tools and verify whether the cutting tools meet both process and usage specifications. If any questions arise, promptly contact the shift supervisor.

　　3. Before processing, operators should first inspect or randomly check the raw blanks of the reaction equipment. After preliminary machining, they should verify the relevant dimensions for this process and confirm that the remaining material meets the process requirements.

　　4. For the first-piece inspection of workpieces, if no specific procedure is stipulated, the inspection should be conducted in a free state—never by pressing the workpiece against the fixture, machine tool table, or any other surface used for support. The workpiece must also be re-inspected after a tool change.

　　5. For processes or operations involving continuous machining, operators may perform self-inspection by process or operation segment. If necessary, they may request the quality inspector to assist with inspection to prevent batch rejects.