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Selection And Sizing Of Marine Loading Arms For Petroleum (Black / White Oil) Products




Selection And Sizing Of Marine Loading Arms For Petroleum (Black / White Oil) Products Dear All,

Todya's blog entry provides a procedure for selection / sizing of marine loading arms

Vessel / Tanker Design Discharge Capacity (Figure 1)

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Oil Tanker Manifold Diameters

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Loading Arm size should not be larger than a maximum of two sizes of the the ships manifold diameter. A smaller size loading arm compared to the ship's manifold diameter is acceptable using a reducing spool piece.

Flow Rate Vs No. of Marine Loading Arms (Figure 2)
Based on limiting flow velocity of 11 m/s (36 ft/s)

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Maximum Marine Arm Loading Flow Rates
Based on Limiting Flow Velocity of 11 m/s (36 ft/s)

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Example Calculation

Inputs
Max Vessel Size = 100,000 DWT
Product Viscosity = Heavy
Pump Type = Centrifugal

Outputs
bbls/hr/DWT = 0.6 (From Figure1)
Correction factor = 0.88
Max. Discharge Rate = 52,800 bbls/hr
Max. Arm Size = 16 inch
No. of Arms = 2 (From Figure 2)

Note:
Part III, Section 2-Guidelines (page 40) of the document "Design & Construction Specification for Marine Loading Arms" which is issued as a standard for MLAs by the "Oil Comapnies and International Marine Forum" with the acronym "OCIMF" recommends a maximum velocity of 12 m/s through marine loading arms.

Looking forward to hear comments from the members of the "Cheresources" community.

Regards,
Ankur.




Hi Ankur; nice selection of topic to share.

We are searching guidelines for nitrogen purging of MLA in case of emergency trip by ESD-2 and after trip how much time shall be kept in margin to reconnect the MLA again after nitrogen purging?

If you can comment on it; will glad to listen it.

Hi Ankur; nice selection of topic to share.

We are searching guidelines for nitrogen purging of MLA in case of emergency trip by ESD-2 and after trip how much time shall be kept in margin to reconnect the MLA again after nitrogen purging?

If you can comment on it; will glad to listen it.

Safety purges with inert gas such as Nitrogen generally involve purging the system volume 8 times to ensure that the system is safe from a flammable atmosphere. Applying this principle you can calculate the time for purging based on your Nitrogen rate.

 

Regards,

Ankur.

Hi Ankur,

 

Thanks for sharing, it was helpful.

 

it would be nice if you can share the reference for the graphs/ charts.

 

Thanks

Hi Ankur,

 

Thanks for sharing, it was helpful.

 

it would be nice if you can share the reference for the graphs/ charts.

 

Thanks

Reference is Exxon design practices.

Hi Ankur or anyone who knows,

 

I am working for a project in Oman and we have been using permanent / fixed marine loading arm in our design for the jetty. However, the client wants to convince the port authorities why we are not using those mobile marine loading arm. Is there any operational, safety and environmental impact using mobile marine loading arm?

 

Please help

Thank you

Lim,

 

Mobile marine loading arms are relatively a new concept. Any information on operational/safety/ environmental issues can only be provided by manufacturers or operators of such loading arms. Some links are provided below:

 

http://www.all-energ...pMZusU_Y_LhOGlw

 

http://loading-arms....arm.html/123680

 

Regards,

Ankur.

Hi Ankur or anyone who knows,

This is mugesh kanna from tuticorin. I thank you for sharing the knowledge regarding Marine Unloading Arm. It would be much helpful for me if you could share some details regarding the Cargo stock calculations and the formula for calculating the ASTM density and Volume Reduction Factor.

Thank u,

Regards

C.Mugesh Kanna

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