Design issues of styrene tanks

The inlet and outlet pipes only need to be connected outside the tank wall; extending the inlet pipe inside the tank wall can facilitate material circulation. Using a lift pipe at the discharge outlet is something that adds an extra touch of elegance. If an internal floating roof is used, some design firms require diffuser tubes to be installed in the tank for the inlet and outlet pipes. The design of the circulation return port should be refined; for a tank with a capacity of 10,000 liters, extending the pipe only inside the tank results in poor circulation effects, and it is recommended to use (rotating) nozzles.

Reply to 2# rctx97: Thank you for the advice. The design of the circular return port isn’t simply about creating an opening; rather, it involves extending a coil inside the tank, with small nozzles installed on that coil. Have you worked on any projects related to the storage and transportation of styrene? Is there any practical experience with using pipe openings in the tank wall solely as feed and discharge ports? The effect is fine, right?

Reply to 3# lvshan2004-9: The storage tanks I have worked on are only 2,000 cubic meters in capacity; they’re not as large as yours. No problem; the difference between styrene and ordinary oils is that temperature needs to be maintained to prevent polymerization.

This post was last edited and replied to by lvshan2004-9 on 2010-10-14 at 17:14. Reply to 4# rctx97: I still have questions: 1. Is there water accumulated in the tank during the storage of styrene? Should a water separation device be installed in the storage tank? 2. For pipelines such as those for loading styrene and those leading away from the plant, which are not continuous but rather intermittent, should the material inside the pipes be emptied or circulated? Or maybe because of pipeline insulation, materials can be inside the pipeline? If running a loop, does it need to run continuously, or is it okay to run it once after a while? If it’s possible to do it through a time-separated cycle, then could we simply install a bypass at the outlet of the loading pump and the pump that transports the fluid to the device, connecting it to the circulating cooling return pipe? 3. How long before polymerization occurs if there is no circulation in a styrene pipeline? I’m afraid that if the amount of material loaded is small, the pipeline leading to the loading site will remain inactive for a long time. It’s also not possible to use the method of connecting a bypass around the pump outlet to create a circulation cooling return line; this method can only ensure flow in the pipeline at the pump inlet, and it cannot be used to create circulation in the area around the pump outlet or in the section leading to the loading site. How to solve it?

Our company has 2 SM storage tanks with a capacity of 5,000 cubic meters each; goods are loaded by ship and unloaded by truck. To answer the original poster’s questions: 4. It’s easy to push the contents around; in summer, the tanks can be emptied, or they can be used to store other benzene-based products. 5. It’s not necessary. 6. It depends on the interval between shipments – we generally require that one truck’s worth of goods be removed from the tank every day in summer, but this isn’t an issue in winter. If too much time passes, sponge balls are used to push the contents back into the tank, along with any waste liquid. The most important thing to note is that the polymerization of SM is very problematic; even a small amount of polymer will spread rapidly within a short time, and the only solution is to empty the tank

Reply to 6# qszks, thank you. Ball receiving and sending devices are installed at the pipe sections unloaded from the dock, but none are installed at the sections leading to the installation site or those for loading onto vehicles. It’s also not practical to install ball-passing devices at every section. So how can aggregation be prevented in such a situation? What measures have you taken?

Last year, the design of 3 styrene storage tanks with a capacity of 10,000 cubic meters was completed, and they were put into use this year, with excellent results. 1. The circulation line does not need to extend into the storage tank. Some have a nozzle installed in the tank at the outlet of the circulation line. I was afraid that the nozzle outlet would be too small, causing the styrene to polymerize easily, so I didn’t use a nozzle. 2. Initially, I also considered that the temperature of styrene in the upper part of the storage tank would be relatively high; by installing outlet facilities in that upper area, it would be possible to circulate the material with a higher temperature there. Later, it was considered that the oil application equipment at the upper part was prone to damage and also quite expensive. Furthermore, having too many internal components in the storage tank is not beneficial for storing styrene, so it was not adopted later on. 3. It is better to have a circular layout for the loading lines for ships and vehicles, as it is always troublesome to pass balls through them. Our design includes a loop line. 4. Styrene is water-free, and no water removal is required during normal storage. Of course, a drain outlet still needs to be provided on the storage tank, equipped with a double valve. 3、

1. For a 10,000-liter styrene storage tank with a fixed roof and nitrogen seal, equipped with external circulation cooling, when opening the inlet, outlet, and circulation return ports, should these ports be similar to ordinary ports with merely a pipe attached to the outside of the tank wall, or should they extend inside the tank wall? It is recommended that the return pipe be fitted with a slope inside the tank; this serves two purposes: to ensure effective mixing of the materials and to minimize static electricity. It is best for the outlet line to have two outlets, one at a higher position and the other in a lower area in the center of the tank. 2. Should the feed inlet extend inward along the tank wall at an upward angle? Yes, this is recommended. K+ P 3. Should a lifting pipe be used for the discharge outlet, so as to allow the styrene from the upper part of the tank to be discharged? (Necessary |0 O0 o$ I7 S5 D+ y$ ]9 i( u7 F Necessary

4. Styrene is unloaded from the ship at the dock and transferred into tanks; in the approximately 1000-meter pipeline from the dock to the tanks, is it better to use circulation or to install ball valves for transfer? It is recommended to use a large-scale circulation system: first, the flanges for sending and receiving the liquid need to be opened, as styrene is after all a toxic and flammable liquid. Second, the effect of using this system for handling the liquid is not very good; without a polymerization inhibitor, styrene will polymerize within a month at most. The process of polymerizing styrene is quite complicated. 5. Is there water accumulation inside the tank during the storage of styrene? Should a water separation device be installed in the storage tank? There is generally no water in the styrene tank, and it is also slightly soluble in water; therefore, a water separation device is not necessary. However, a slop tank is required. 6. The pipelines for loading styrene and those for transferring it to other devices are not continuous but rather intermittent – so should the material in these pipes be emptied or circulated? Or maybe because of pipeline insulation, materials can be inside the pipeline? A circulation process is required. If there is a dedicated pump for cooling the tank, connect the pipeline to the tank’s cooling circulation system; if not, use a loading pump or a feed pump to carry out regular large-scale circulation. It is important to monitor the temperature of the material in the pipelines. Polymerization of styrene inside the pipelines can cause various problems, so caution is needed

Thank you all for your generous help. I would like to add two more questions: 1. Is it necessary to apply anti-corrosion treatment to the inner wall of the styrene tank? How to do it? 2. How are the model of the heat exchanger required for external circulation cooling of styrene, and the cooling capacity of the chiller generally determined? Is it calculated step by step based on the heat absorption rate of the tank’s surface, or is it determined empirically based on the tank’s volume?