Questions regarding the selection of loading/unloading arms for oil terminals

This post was last edited by oil transfer arm on 2009-5-18 20:54. First of all, I’m not sure why the original poster chose other options; it’s not that we can simply choose whatever diameter of oil transfer arm we want – there must be a basis for such a choice. Secondly, I would like to tell the original poster that the largest diameter of oil transfer arms currently in use in China is DN500; it is possible to use oil transfer arms with larger diameters, and there are many options available with smaller diameters, so no need to go into detail on that here. Again, the number of oil transfer pumps required can be determined by taking into account various factors such as the quantity of medium in the operation area and the unloading time. Finally, since there are many 300,000-tonne docks (and several more that the original poster didn’t mention) that use DN400 oil transfer arms, there must be a reason for that; please consider all factors before making a decision.

That’s indeed the case with the 2# oil transfer arm. I searched online for more examples, and it turned out that all large oil terminals use DN400 pipes; so it seemed strange to me, and that’s why I came here to ask everyone~

Is the largest diameter of oil transfer arm currently in use in China DN500? Could the original poster let me know which project it is? The diameter and number of oil transfer arms should be determined based on various factors such as the type of cargo to be transported (the principle that oil transfer arms for similarly characterized cargos should serve as backups for each other), as well as the type of transport vessel (ship size – loading and unloading efficiency). However, they must comply with the usage limits specified in the standards; JTJ211-99, the \"Code for General Layout Design of Seaports\", specifies an average flow velocity of 8.5 m/s within the oil transfer arms ； According to 6.1.5 of JTS165-8-2007, the internal flow velocity of the loading/unloading arm should not exceed 10 m/s ； All of the above are for reasons of electrostatic safety. I saw that the flow velocity within the oil transfer arm is stated to be less than 11 m/s; this seems to be based on considerations related to the overall structure of the oil transfer arm. Additionally, according to JT/T398-1999 \"Port Oil Transfer Arms\", section 5.1.5, the flow velocity of the liquid inside the oil transfer arm should not exceed 11 m/s. If this velocity is exceeded, it is necessary to check for cavitation – what does checking for cavitation entail? What thing? I’m not sure about this; please ask someone who knows to explain it

A air pocket, I think, is a low-pressure area that forms within a pipe when the flow velocity is too high; this causes the dissolved gases to escape or the liquid to vaporize, resulting in bubbles forming in the flow channel. When these bubbles are under pressure, they burst and may produce a popping sound. Cavitation can cause significant metering errors in mild cases, and may even damage the equipment in severe cases.

It is mainly considered from the perspective of flow velocity.

Reply to the question from the fourth floor: It seems that the person on the fourth floor has doubts regarding the DN500 oil transfer arm. You can visit the following link: http://www.zgsyb.com/Article/ArticleShow.asp?ArticleID=40884, or read the corresponding article. By the way, I am the one who wrote about the oil transfer arm; I’m not the original poster. Dalian Port has developed the world’s largest oil transfer arm, with a standing height of 25 meters. Source: Internet Center. Publication date: 2008-03-18 08:22:18. Number of views: 109. The first oil transfer arm of its kind in China, and currently the largest in the world, was successfully installed and tested at Dalian Port’s 300,000-ton crude oil terminal. It was designed and manufactured by Dalian Port Group itself. It is understood that this DN500 millimeter oil transfer arm stands 25 meters tall when at rest, with a single-unit oil transfer capacity of 6,000 cubic meters; it is capable of handling oil tankers ranging from a minimum of 150,000 tons to a maximum of 500,000 tons in size. It is expected to come online for use next month. In September 2006, with the completion and operation of the 300,000-ton crude oil terminal at Dalian Port, the DN400 mm oil transfer arms designed and manufactured locally by Dalian Port Group could no longer meet the loading and unloading requirements of the increasing number of large oil tankers. Dalian Port Group proposed a plan to design and construct a DN500 millimeter oil transfer arm last year. After 8 months of development and testing, the DN500 millimeter oil transfer arm, designed by Dalian Port Design Institute and constructed by Dalian Port Machinery Co., Ltd., was finally brought to market. It is reported that the DN500 millimeter oil transfer arm is currently the largest of its kind in the world; it not only fills a gap in this technology in China but also **will increase the loading and unloading efficiency of crude oil terminals with a capacity of 300,000 tons. The image shows the installation site of the DN500 mm oil transfer arm. -----Reposted from: Dalian Daily

A diameter as large as DN500 is only used at large docks

Reply to 8#: The selection of the loading/unloading arm for imported chemical processing equipment is determined based on several factors: the type and tonnage of the ship, the loading/unloading time, as well as parameters such as the process pipelines and pumps

So how do we determine whether a vapor recovery line for the oil transfer arm is needed? Such as gasoline, jet fuel, diesel, etc.