Storage and Transportation Technology: [Weekly Topic] November 4–11 to April 17 – Comparison of the advantages and disadvantages of liquid hydrocarbon spherical tanks and horizontal tanks

There’s a problem with the topic itself. Storage tanks are generally built to be quite large; for example, those with a capacity of 2000 cubic meters as you mentioned. Horizontal tanks, on the other hand, are smaller, with a maximum capacity of around 100 cubic meters. I have worked on custom storage tanks with an elliptical vertical head and a capacity of 300 cubic meters. If you need tanks with a capacity of 2000 cubic meters each, then 20 such tanks would be required, which means 20 sets of automatic control instruments would be needed – making operation and management extremely inconvenient. The more storage tanks there are, the more leakage points there will be, and thus the greater the safety risks. There’s no need to mention other factors either; therefore, there’s no way to compare them. Generally, storage capacities over 1000 are not considered worth considering, and spherical tanks are preferred in such cases

Reply to 2# Storage and Transportation Engineer: You’re out. Now, large horizontal tanks (bullets) are used abroad. You can look up some relevant information. Although the conventional approach in China for liquefied hydrocarbons remains the use of spherical tanks or cryogenic tanks, large horizontal tanks have become an international trend. In particular, the use of large horizontal tanks with soil covering has gradually replaced spherical tanks. For large-scale (under 10,000) liquefied hydrocarbon storage in Europe, the United States, the Middle East, and other regions, horizontal tanks are generally preferred. Horizontal tanks have significant advantages over spherical tanks in terms of safety and other aspects. But low investment is indeed an advantage of spherical tanks. Therefore, the comparison between spherical tanks and horizontal tanks is something that must be addressed when constructing large liquefied hydrocarbon storage tanks both domestically and internationally. I’m just throwing out an idea to inspire others, waiting for those more skilled to come forward.

This post was last edited by the Logistics Engineer on 2011-4-11 at 17:51. It’s really hard to understand – the stress conditions on spherical tanks are much better than those on horizontal tanks, and the corrosive effects resulting from burying horizontal tanks are another issue that needs to be addressed. I can’t see any advantages to them. The poster could share some materials or information; it would be interesting to study them. Does it have greater advantages over spherical tanks? ? ? What are the advantages?

Compared to cylindrical vessels (i.e., conventional storage tanks), at the same diameter and pressure, spherical tanks have shell wall thicknesses that are only half those of cylindrical vessels; this results in less steel being used, a smaller footprint, and simpler foundation work. However, the manufacturing, welding, and assembly of spherical tanks require strict standards, involve substantial inspection work, and result in high production costs.

Reply to 4# Storage and Transportation Engineer: Mounded storage is used because it offers greater safety compared to storing gases above ground in spherical or bullet-shaped tanks. Its main advantage is that a BLEVE incident is practically impossible. Other benefits of this storage method include: • it protects the tanks from heat radiation from nearby fires, pressure waves resulting from explosions, impact from flying objects, and acts as a barrier against sabotage; • it meets environmental and aesthetic requirements; • it reduces the required site area since there are less strict spacing requirements; • the safety distance from the site boundaries can be significantly reduced. Source: EEMUA 190-2000 Guidelines for the Design, Construction, and Use of LPG Tanks Buried in Soil.rar These are all the advantages of using buried tanks

Reply to 4# Storage and Transportation Engineer: Mounded storage is used because it offers greater safety compared to storing gases above ground in spherical or bullet-shaped tanks. Its main advantage is that a BLEVE incident is practically impossible. Other benefits of using mounded storage include: • it protects the tanks from heat radiation from nearby fires, pressure waves resulting from explosions, impact from flying objects, and acts as a barrier against sabotage; • it meets environmental and aesthetic requirements; • it reduces the required land area since there are less strict spacing requirements; • the safety distance from the site boundaries can be significantly reduced. The above text is taken from EEMUA 190-2000, Guidelines for the Design, Construction, and Use of LPG Tanks Buried in Soil. These are all the advantages of using mounded storage tanks.

This post was last edited and replied to by the Logistics Engineer on 2011-4-12 at 12:57. Reply 7# MintLife: Haha, of course we know about his advantages without even looking at them. How to address the following issues: 1. Corrosion prevention. 2. Once corrosion leads to perforations, or if the storage tank leaks for other reasons, how to identify the location of the fault and how to carry out repairs. I am looking for information that can help solve these problems, as well as understanding how such large-scale systems are made possible – it seems like something out of fantasy. It’s okay to cover the small pot with soil. As you said, I consulted some people about this, and they really hadn’t heard of it either. The original poster is really amazing.

Reply to 8# Storage and Transportation Engineer: To be honest, I work in the process area, so I’m not entirely familiar with some aspects of the equipment. If you need to understand the relevant details, you can study the standards. Of course, in fact, Yangzi BASF in China currently has ethylene horizontal tanks (with a capacity of over 1000 m³), and several equipment manufacturers in Jiangsu also possess similar design and manufacturing experience. You can search online; there should be relevant information available. It might be a bit new, so it’s not widely used in China at the moment.

The disadvantage of horizontal tanks is the high amount of steel required per unit volume; when storing a certain quantity of material, many such tanks are needed, which results in large floor space requirements. The advantage of spherical tanks is that, when their volumes are the same, they have the smallest surface area ； When the pressure and diameter are the same, its wall thickness is only about half that of a cylindrical tank ； When the diameter and wall thickness are the same, its pressure-bearing capacity is approximately twice that of a cylindrical tank; thus it can save a large amount of steel and reduce floor space, making it suitable for manufacturing medium-pressure vessels. On the other hand, the spherical tank shell is a biconic surface, making on-site assembly difficult; the working conditions are poor, the technical skills required of welders are high, and the manufacturing costs are elevated.

Zhenjiang BASF has ECT tanks (Earth Covered Tanks), and the Formosa Plastics Sixth Light Industry Project has dozens of such tanks in operation. The advantages of these tanks go without saying, as several people have already mentioned them above. The main reason why they haven’t been widely adopted in China is that existing fire safety regulations for the petrochemical industry do not cover this aspect; furthermore, the regulations regarding the periodic inspection of earth-covered storage tanks are still lacking. The Ningbo Petrochemical Economic and Technological Development Zone plans to use ECT tanks for the storage and transportation of liquid hydrocarbons, and preliminary work is currently underway in this regard.