Urea Prills strength

Urea Prills strength

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Urea Prills strength

by GIRISH PRAKASH » Fri Feb 01, 2013 7:55 am

Dear Friends,

Is there any mathematical expression to show the corelation between the crushing strength of Urea prills and the vacuum maintained in the evaporators at constant bucket speed/ plant load? Can we predict the crushing strength / load?

Regards,
Girish

GIRISH PRAKASH

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Re: Urea Prills strength

by Muhammad Aslam » Sat Feb 02, 2013 4:52 am

Girish, it is not practical to define a specific correlation for the subject case as vacuum, plant load and bucket speed are not the only parameters who affect prills mechanical strength. The other paramters are air flow thru prill tower, ambient conditions, prill temperature which are always keep on changing. Since all these parameters are not controllable at any constant level, therefore, it is difficult to establish a definitive relationship for vacuum vs crushing strength. Any how, Mark can comment better.

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Re: Urea Prills strength

by gyasuddin » Fri May 09, 2014 6:42 am

There is no direct mathmatical formula to calculate CS in respect of Vacuum in evaporators.
The main reason of CS variations are;
1. Relative humidity of air
2. Vacuum variation in evaporators.
3. Plant Load
4. Prill temperature
5. Length of transportation through conveyor
6. Air intake (Quantity and Temperature) through Prilling Tower.

Hope above points will clarify your question.

Regards
Gyasuddin Ali
CFCL

Crushing strength of urea prills

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Crushing strength of urea prills

by ranjeetjadhav » Sat Apr 25, 2015 9:49 pm

Hello Everyone
Iam working with Urea plant( Snamprogetti) capacity:1250 MTPD
& we r using tuttle bucket for prilling
I want to know abt ...
-wht is the desired crushing strength of urea prills
- wht are the possible causes for low crushing strength & remedies for the same
- HCHO injection method.

plz share ur views.

ranjeetjadhav

 

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Urea Plant Technology: snamprogetti

Years in operation: 5

Design Capacity [mtpd]: 1200

Actual Capacity [mtpd]: 1310

Final product: Prills

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Re: Crushing strength of urea prills

by pbaboo » Tue Apr 28, 2015 11:59 am

Dear Mr. Ranjeet,
Crushing strength depends upon Vacuum condition, free ammonia present in molten urea prill size distribution.The crushing strength of fertilizer particles differs greatly depending on the chemical composition. Mechanical resistance is the ability of the fertilizer to resist the stresses imposed upon them in the handling chain. The mechanical resistance depends on surface structure and particle strength. Dust and fines normally arise during handling from
Water absorption 
• Poor surface structure and particle strength 
• Low mechanical resistance 
• Mechanical stresses in the handling chain 
• Wear and tear from equipment (scrapers, screw feeders, grain trimmers etc) See also how to prevent dust formation.
Crushing strength is the minimum pressure needed to crush individual particles. Determining the crushing strength, or hardness, will help determine handling and storage requirements of a chosen granular product.
generally the crushing strength in our unit about 700 gm to 1.2 Kg per prill. The crushing strength of Granule Urea is about 1.3 to 3.2 kg per granual.
The crushing strength widely depends upon moisture & Prills Temp 
• MAXIMUM STRENGTH 930 Gram/prill at 0.1777% Moisture.
• Below 0.12% Moisture strength reduced 698 gram/prill.
• Above 0.3% moisture strength=640 g/prill.
• At 40 deg C Maximum strength 850 g/prill
• Below 34 deg C the strength reduced 640 g/p.
• Above 66 deg C the strength reduced 640 g/p.
• OBSERVE THE ABOVE RESULT PRILLS STRENGTH IS MAXIMUM AT TEMPERATURE 40 degC & MOISTURE 0.1777%
For More detail Please read following links.

viewtopic.php?f=7&t=1012&p=5352&hilit=crushing#p5348

viewtopic.php?f=7&t=712&p=3699&hilit=crushing#p3699

viewtopic.php?f=7&t=629&p=3189&hilit=crushing#p3189

Regards,
Prem Baboo

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Years in operation: 29

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Actual Capacity [mtpd]: 3150/3600

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Re: Crushing strength of urea prills

by giorgio » Tue Dec 22, 2015 4:13 pm

Hi Prem..
a lot depends on which particle size you did the crush strenght test on fro pril and granule ... (SGN figure, d50)
smaller particles tend to be weaker!

drs. ing. B George van Bommel
sr. Energy Systems & Fertilizer Consultant

giorgio

 

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Re: Crushing strength of urea prills

by pbaboo » Wed Dec 23, 2015 7:09 am

Dear B. George
The above practical’s done at constant prills size, and variation in temperature & moisture.
The following sieve analysis is used for above practical’s, for strength average Crushing strength is used for different particle size with its percentage.
-2.8+1(normal Size)
96.32 %
+2.8(Oversize)
2.26%
-1+0.85(undersized)
0.96%
And -0.85
0.46%

Regards
Prem Baboo