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Maximum Height Of Petroleum Storage Tank


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#1 jrtailor09

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Posted 08 December 2011 - 06:19 AM

Dear all,

What should be maximum hight of petroleum storage tank?

As per my knowledge Indian guidlines says that the height of petroleum product storage tank shall not be more than 20 m. What is a reason for the same ?

I have seen in gulf the petroleum product storage height is more than 20 m.

Is there any guidlines providing restrication on maximum allowable height for tank ?

Regards,

Edited by jrtailor09, 08 December 2011 - 06:21 AM.


#2 ankur2061

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Posted 08 December 2011 - 09:53 AM

Jatin,

Although I am not a mechanical static engineer I certainly do know that as the height of the tank increases it's cost increases due to the fact that taller the tank the more stiffening you have to provide to the walls of the tank thereby increasing it's cost.

So most economiclly designed very large storge tanks have L/D ratios of 0.5 or less.

If you are interested in details about stiffening of the tank walls then you should refer to API STD 620 - Design and Construction of Large, Welded, Low-pressure Storage Tanks.

Another very good reference for design of storage tanks is:

"Guide to Storage Tanks & Equipment" by Bob Long

Hope this helps.

Regards,
Ankur.

#3 kkala

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Posted 09 December 2011 - 03:03 PM

A. Observed API 650 tanks in refineries seem to have diameter considerably larger than height, apparently for economic reasons. In chemical industry tanks of height considerable larger than diameter can be observed. Subject is discussed in thread http://www.cheresour...ric-acid-import and web references mentioned there. Space limitations can dictate a larger height.
B. Following of para Γ indicates that API 650 does not limit height of tanks directly. But tanks heigher than 30 m have not been found and tanks heigher than 23 m are seldom, due to special requirements on structure and foundataions, also meaning excessive capital cost. Normal API 650 tank height is below 23 m.
This seems to be more or less true also for other codes (BS2654, DIN4119, etc).
Apart from economic factors, local authorities can specify max height for tanks, as they do for buildings.
Γ. Web search for max height of API 650 tanks.
1. http://www.slideshar...orage-inquiries
"3. Standard Edition Section Inquiry # Question Reply 650 9th - May 3 : Please furnish details on the maximum allowable tank diameter and The appropriate combination of tank diameter and height is a 1993 height for tanks built in accordance with API 650. design consideration. There are several factors which influence this. API 650 does not cover an explanation of these factors. Please note the thickness limitations given in Section 2.2.2".
2. http://www.ast-forum...sp?master=14324
-My client request for 25M diameter x 27M height for chilled water storage tank design.
According to API 650, the maximum height standard is 75Ft, which is +/- 23M height,
so can the design be done? What is the requirements to design such tank? Is there any supporting
paragraph in API 650?

-API does not restrict tank height. Where are you finding this?
-Yes, fully agreed with Mr. David, API does not restrict on height.....
3. http://www.outokumpu.com/33262.epibrw
API 650 tank of H=30 m and D=12 m is considered (p. 4/10), partially of stainless steel.

4. http://www.eng-tips....d.cfm?qid=29340
-I am in the engineering department of a paper mill, and I am trying to get a handle on the cost of a storage tank for 350,000usgal of 5% OCC paper stock. Our mill is short on real estate, so my manager is asking me to look at putting it in some pretty tight spaces, which would dictate a small diameter (< 35'). My question is, does API-650 or any other standard give limits, or rules of thumb for height/diameter ratios for steel tanks?
Also, at 5% +/- consistency, a high density storage tower design may have to be employed here. Would any of you know of any standards that might apply to this, or of any reasonable height/diameter ratio to shoot for in this design? Agitation may become a factor at this point, too.

- No, API 650 does not resrtict the height/diameter ratio...usually, it is economics that dictates, but I see that you are in a restricted space.. For your 350,000 gallon tank, I get about a 48 foot shell at 35 feet diameter..... This is well within the "normal and reasonable range" for flat bottomed tanks. Realize that your shell wall thickness will taper as you go up the tank.
About the highest "aspect ratio" tanks that I have seen were shop built tanks 10 foot diameter and 38 feet high ( about 3.8 to 1)
Give some thought to allowing 3 to four feet minimum all around the tank. Decide upon the method of support for the tank ( Ring wall !??) and also consider performing a study of the ground to support the tank weight. Will the tank need agitation or a sloped bottom ? What kind of coatings will be required ? You should have a really good idea about materials and coatings if this is your process....
Based on my experience, the foundation and coatings questions can strongly affect the tank cost.

-Thanks for your reply. Believe it or not, my manager has asked me to look at places that would allow as little as 27' in diameter, which push the required height into the 90' tall range which I think would be pushing the limits of reason. And if, as you say (and I strongly agree, by the way) I allow a few feet around the tank for maintenance and regular access, then it will resemble our boiler chimney more than a tank! But, I guess as a manager he has to look at all possible options. I have difficulty getting estimates on a tank that's 25' in diameter and 110' tall, though!
Fortunately, our mill site is a good one for ground conditions - typically only 5-6 feet to 'refusal', so the bedrock is close at hand. The tank would definately require a sloped bottom, and agitation in the dilution zone at the bottom, or the contents would bridge. We have enough trouble with previously installed storage tanks, and I don't want my name on anything like that! It would also have to be insulated, so the 'system' costs will quickly dwarf the tank costs.
-Do not forget seismic requirements in your design. If you are in an earthquake zone a tall tank it may not work or not be cost effective.
You could also talk to tank vendors, such as CBI Horton, who have made these tanks before and know what can or cannot be done.

-Nearly anything is POSSIBLE. But a 27'D x 90'H tank would have some difficulties. The foundation design to resist the seismic and wind moments (not to mention dead weight) would be a challenge. Also, the tank's shell will need to be thicker than you think near the bottom to avoid buckling under the moment loading of seismic and wind. It is very likely not the most economical solution.
I would also have a concern with regards to the dynamic stability if only API 650 is used in the design. It is very possible that the tank could have lateral vibration problems if they are not considered in the design. The normal range of D/h for API 650 tanks precludes this problem, so API 650 doesn't address it. Someone who builds tall steel stacks and/or tall vertical vessels should be consulted if you are serious about such a tall skinny tank.

5. http://kennedytank.t...anks/item-1008'> http://kennedytank.thomasnet-navigator.com/item/all-categories/api-650-storage-tanks/item-1008
We manufacture storage tanks that conform to the American Petroleum Institute (API)-650 standard. The storage tanks fabricated can be of sizes up to 14 feet in diameter and 70-feet in height. These tanks are API compliant for storing petroleum and other petroleum products, such as gasoline as well as other liquid products.

#4 ankur2061

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Posted 09 December 2011 - 11:04 PM

Jatin,

I am amazed with the responses coming to you. I thought you are very much capable of opening weblinks instead of the whole matter from a particular link being copied as a response. Don't you think it is a waste of space and resources?

Regards,
Ankur.

Edited by ankur2061, 09 December 2011 - 11:05 PM.


#5 jrtailor09

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Posted 10 December 2011 - 02:37 AM

Ankurji

Thank you very much for your input. Generally diameter & length will be decided by process engineer accordingly the volume of liquid required to store on the basis of different scenario.

I will try to locate the reference given by you.

Regards,

Jatin Tailor

#6 jrtailor09

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Posted 10 December 2011 - 02:55 AM

kkala ,

As per above reference following outcome related to maximum height of tank.

1. I think this link shows updaton in API -650 from year to year need to look as it is lengthy document (26 pages)
2. It is says that API does not restrict on maximum height & L/D ratio suggested by Bmac is less than 1.
3. This article is saying example for the storage of marble dust (CaCo3 ). As per that height to dia meter ration is coming very high 2.5.
4. It is not clear for height to diameter requirement.
5. This vendor ( kennedytank ) giving the maximum possible diameter & height of tank able to fabricate.

Once again i will look further.

Thanks & regards,

Jatin tailor

#7 kkala

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Posted 10 December 2011 - 06:05 AM

Jatin tailor, you apparently refer to para Γ of kkala's post. As said there, the presented extracts from links intend to support what is written in para B of mentioned post, where the conclusion is. Brief response to your comments is following.
1. I think this link shows updaton in API -650 from year to year need to look as it is lengthy document (26 pages).
Whole document is hard to read, but its points cannot be contradictory. The point is just an indication that specifying max diameter or height for tanks is avoided.
2. It is says that API does not restrict on maximum height & L/D ratio suggested by Bmac is less than 1.
Let us keep that "no restriction of height" by API.
L/D less than 1 favors economics (as clarified in all posts). This is not mandatory. It can be different, e.g. when available space is limited.
3. This article is saying example for the storage of marble dust (CaCo3 ). As per that height to dia meter ration is coming very high 2.5.
The point is that API 650 can be adopted for the construction of this tank, even if L=30 m.
4. It is not clear for height to diameter requirement.
Proposed D=35 ft & L=48 ft, then D=27 ft L=90 ft considered marginally possible. Doubts on D=25 ft & L=110 ft. "API 650 does not restrict L/D, it is economics that dictate"
5. This vendor ( kennedytank ) giving the maximum possible diameter & height of tank able to fabricate.
True, indicating that even for D=14 ft, H=70 ft is possible as standard height.

Hopefully above gives additional clarifications to conclusions of para B of the post by kkala; also indicates the need of "digging" for a documented (to the extent possible) answer, not limited to the economically optimum L/D. Please also consider restrictions of tank height, potentially imposed by authorities (mentioned in kkala's post). Tank heights even higher than 30 m are realized in specific cases.

Edited by kkala, 10 December 2011 - 06:08 AM.


#8 ankur2061

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Posted 10 December 2011 - 11:20 AM

Jatin,

There was a good discussion on L/D ratios of atmospheric storage tanks on the forum sometime back. Below is the reference:

http://www.cheresour...tanks-ld-ratio/

There is an excel sheet posted by me for standard sizes for vertical cylindrical storage tank dimensions for a given volume in the post whose link is provided above.

Regards,
Ankur.

#9 kkala

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Posted 10 December 2011 - 05:43 PM

α. Mentioned thread http://www.cheresour...tanks-ld-ratio/ reveals following (among other data):
α1. S Mukherjee's Table reports dimensions of standard tanks. Max height is 25 m for every diameter larger than 15 m. Lower diameters have lower max height (reasonable).
α2. It seems that tanks higher than 15 m are not very common.
Note: Only once have we determined tank diameter and height considering standard sheet dimensions.
β. As tank height increases, plate thickness increases; besides requirements for foundations & earthquake protection get more sophisticated (so more expensive); and so do requirements for tank stiffness, to resist buckling (and bending moments) for high H/D ratios. A practical limit of height = 30 m could be considered, according to previous posts. Over here petroleum tanks of height = 23 m are not rear.
γ. A verified example from precipitators, used as crystallizers in alumina production, concerns atmospheric tanks, each of them of D=14 m, H=29.3 m, total weight ~220 ton (empty). They had to be high for following reasons ( increasing importance, last reason most important).
- there would be ~ 30 tanks in total, bigger diameter would mean more space.
- each tank had an agitator to keep particles in suspension (agitation is not efficient in big diameters)
- there was a platform at H=28 m (say) communicating with all tanks. Valves had to be manipulated (not in every shift) from the platform.
Plant layout was affected by the need of Precipitators' foundation to be on rock. Area was of high seismism, requiring special survey for the protective measures in an earthquake. Stored liquid oscillations during it (with risk of caustic liquid to pour out) imposed covered tanks, contrary to usual practice of open tanks.
So these are some special issues faced with high tanks.

Edited by kkala, 10 December 2011 - 10:43 PM.


#10 ankur2061

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Posted 10 December 2011 - 11:14 PM

Jatin,

I believe you started out with petroleum storage tanks or is it that now you require information on precipitators in alumina production.

Regards,
Ankur.

#11 kkala

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Posted 11 December 2011 - 12:14 AM

Jatin,I believe you started out with petroleum storage tanks or is it that now you require information on precipitators in alumina production.Regards, Ankur.

Precipitators indicate the issues encountered in the construction / installation of 30 m high tanks, either for petroleum storage or not. Such tanks have been constructed. The reasons of constructing such high tanks are reported as an example.

Edited by kkala, 11 December 2011 - 12:19 AM.


#12 kkala

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Posted 12 December 2011 - 08:35 AM

Jatin,I am amazed with the responses coming to you. I thought you are very much capable of opening weblinks instead of the whole matter from a particular link being copied as a response. Don't you think it is a waste of space and resources? Regards, Ankur.

Looking into them (has been realized by others) justifies conclusion of max height = 30 m in a non dogmatic manner. This is explained in kkala's post of Dec 10th. It is not "the whole matter", but just the point of interest. No 4 is almost all because of its useful information. Relevant data discussed in Cheresources' threads are also confirmed there.
As an attachment these would be difficult to read. Located after the test, you are not confused. You could read only the conclusion, neglecting them.
Besides, this specific issue should have been addressed to kkala.




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