Saturday, June 16, 2012

CARGO RECIRCULATION AT SEA, ON CHEMICAL TANKERS-- CAPT AJIT VADAKAYIL

CARGO RECIRCULATION AT SEA, ON CHEMICAL TANKERS--  CAPT AJIT VADAKAYIL


The last stainless steel chemical tanker I commanded was less than a year old.

They managed to screw up most of the super-expensive cargo hoses, while doing cargo reirculation at sea ( Kaolin clay slurry )


The ship had fantastic diffusers for the drops and it was NOT necessary to do bottom to top recirc with cargohoses.



Chemical tankers have very little freeboard in the loaded passage and the cargo hoses full of slurry hung up with slings can get very heavy --and with rolling get damaged badly.

There is a saying " Stupid is forever!"


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From: XXXX (Master) [mailto:master.XXXX@gtships.com]
Sent: 04 January XXX 15:09
To: XXX
Cc: XXXX



Subject: RE: XXXX/ ALICE IN CLAY SLURRY

gentlemen,



in july 2010, fairchem yuka carried clay slurry.



to keep the clay slurry from sedimenting—this ship used bottom to top recirculation at sea by using cargo hoses—as per charterers instructions.


this was as ridiculous as , having a computer but using burtons tables to calculate.

nobody knew what the computer could do!!



these cargo hoses are NOT meant to do such gymnastics, tying up with ropes with ship rolling.  they are meant for internal looping at the manifold.



so XXX of the hoses got condemned. 



we now have XX hoses only, instead of XXX brand new hoses ( XXX supply ).



just check out the pictures of the cargo hoses —see how badly they got damaged.



LEARNING TIME –



PL PUT YOUR THINKING CAPS ON --



on XXX we have 16 nos recirculation nozzles.


in scientific parlance this hardware is called DE-AGGLOMERATOR –or—DE-FLOCCULATOR.



now why does clay slurry get sedimented?—pray?


because the colloids are NOT stabilized ( like latex ) to prevent agglomeration.


the electric charge is neutralized.

STABILISING IS ALL ABOUT STATIC ELECTRICITY AND ELECTRIC CHARGES.
when you put egg whites and vegetable oil and beat them in a mixer, you get mayonnaise—it remains so because of electric charges, which keep colloids apart.


when colloids combine they flocculate to form clumps and settle down. heating or centrifuging is one way.


adding electrolytes to remove electric charges is another way—the way they do it for lub oil for easy filteration.



SO WHEN YOU RECIRC CLAY SLURRY BY FORCING CARGO THROUGH THESE TINY ORIFICES—YOU BUILD UP ELECTRIC CHARGE AND KEEPS THE CLAY SLURRY IN SUSPENSION. 


THE COHESIVE FORCES ARE WEAKENED BY AGITATION TOO.



in future in my vision I see CAVITATION nozzles , where the imploding air bubbles will create 2000 bars of homogenization effect.


thanks and best regards
capt. ajit vadakayil
master
mt XXX



master's cabin phone : +870 XXX (Inm F77)-- first call
bridge  phone :  +870 XXX (Sing Tel-FBB ) -- second call
bridge phone: +870 XXX (Inm F77)
fax -  : +870 XXX (Inm F77)
tlx ( sat c) : +870 XXXX 

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A stable colloidal system is one in which the particles resist flocculation or aggregation and exhibits a long shelf-life.



This will depend upon the balance of the repulsive and attractive forces that exist between particles as they approach one another.



 If all the particles have a mutual repulsion then the dispersion will remain stable. However, if the particles have little or no repulsive force then some instability mechanism will eventually take place e.g. flocculation, aggregation etc.



In certain circumstances, the particles in a colloidal disperson may adhere to one another and form aggregates of successively increasing size that may settle out under the influence of gravity. An initially formed aggregate is called a floc and the process of its formation flocculation. The floc may or may not separate out.



 If the aggregate changes to a much denser form, it is said to undergo coagulation. An aggregate usually separates out either by sedimentation (if it is more dense than the medium) or by creaming (if it less dense than the medium).



The term’s flocculation and coagulation have often been used interchangeably. Usually coagulation is irreversible whereas flocculation can be reversed by the process of deflocculation. The following figure schematically represents some of these processes.





CAPT AJIT VADAKAYIL
29 YEARS IN COMMAND
..

8 comments:

  1. Dear Captain Vadakayil

    Many thanks for your blog.
    Please, can you explain me what is agitation? And what is a diffuser used during cargo agitation?
    Many thanks in advance,
    Best regards
    F. Esteves

    ReplyDelete
    Replies
    1. hi fa,

      i have explaines it in the post above.

      some solid cargoes are carried at sea in a liquid form.

      for example solid clay is made into a slurry and carried at sea , as it is cheaper.

      during tha passage the solid and water will separate out--causing a sediment at the bottom.

      this is NOT good,as the pump impeller is right at the bottom and will get cemented. and at discharge port, ship cant pump out cargo and then has to be pumped ashore using a portable pump.

      so at sea, the same pump is used to push the cargo back into the tank through small orifices or diffuser nozzles. tank to tank recirc.

      this causes a static electricity charge which keeps the solids in suspension.

      capt ajit vadakayil
      ..

      Delete
    2. Dear Captain Vadakayil

      Many thanks for the explanation.
      Best regards
      F. Esteves

      Delete
  2. Dear Captain Vadakayil
    In specialized cases, is required to prevent products from giving-off toxic and flammable vapours.
    Can you please give me one or two names of cargoes that need to be cooled to prevent giving-off those vapours?
    Many thanks in advance,
    Best regards
    F. Esteves

    ReplyDelete
    Replies
    1. hi fernando,

      certain chemical have very low boiling points-- and if the outside ambient temperatures exceed the BP, the cargo will flash into vapour -- which is very dangerous.

      such cargoes must be carried in gas tankers and NOT chemical tankers -- unless they have cooling systems.

      punch into google search PROPYLENE OXIDE ON CHEMICAL TANKERS VADAKAYIL

      capt ajit vadakayil
      ..

      Delete
    2. Dear Captain Vadakayil

      Many thanks for your help.
      Best regards
      F. Esteves

      Delete
  3. CH
    October 13, 2014 at 6:35 AM
    Respected Captain,

    What is special about Tamil Nadu?

    How come it is able to continuously produce word geniuses like Ramanujam, Subrahmanyan Chandrasekhar, C.V. Raman, A.R. Rahman, Abdul Kalam, Venkatraman Ramakrishnan, Viswanathan Anand, Illayaraja, etc?

    Even till recently the Chief Justice of India, the Finance Minister, the RBI governor are all Tamils?

    Is there any scientific reason behind this? Because no other region has produced such super genius people in such numbers.

    Regards

    ReplyDelete
    Replies
    #####################
    Capt. Ajit Vadakayil
    October 13, 2014 at 7:06 AM
    hi ch,

    i am sure if i were a lawyer, i will NEVER EVER become CJI.

    i am sure if i were an economist, i will NEVER EVER become finance minister.

    you want me to continue ?

    when i was on my training ship in mumbai with 250 other cadets ( two years ) -- the biggest TELUs ( oily and slimy ) and SNEAKS ( snitches ) became SCC ( senior cadet captains ) , CC ( cadet captains ) , CL ( cadet leaders ) etc.

    i used to be in the CAPTAINS MONTHLY BREAKFAST PARTY ( cadet with maximum negative marks for OFFICER LIKE QUALITIES ) -- to be chewed up for breakfast every month .

    i got an EXTRA FIRST in every subject --except OFFICER LIKE QUALITIES.

    now what are OFFICER LIKE QUALITIES-

    being a son of a bit#h, being a sneak, being a hypocrite, being a as$ kisser , being a leader who will sell out his team, being a back biter, being an informer , being the best in playing to the gallery.

    so, so--

    at the passing out parade --most of the cadets who got all PRIXES were leaders -- they all got BOOOOOEEEEED !

    I remember i got only one prize--for being the best REPORTER IN ENGLISH -- the claps I got from the entire hall still resound in my ears -- along with another ROC ( royal officer cadet -who did NOT care to become a sold out leader ).

    and mind you -- i was in every single team which made my TOP ( starboard fore top ) the champion TOP.

    i was a champion sailor, rower, signaller, marks in subjects, soccer team in both years --

    but i lacked OLQ ( officer like qualities ) of being a FU#KIN' SLIME BALL.

    so in my passing our certificate , after two years of training -- i had an EXTRA FIRST in all subjects -- except OLQ where i was third grade

    so i guess they held a special meeting and GRACED ME TO FIRST CLASS --a young 18 year old boy -- .TEE HEEE !

    AT SEA, THE SAILORS DO NOT CARE FOR YOUR FOUR STRIPES- THEY ONLY CARE FOR WHO YOU ARE--

    AT SEA PEOPLE WHO KNOW ME , OR HAVE HEARD OF ME -- OR SAILED WITH ME, WILL VOUCH--

    CAPT AJIT VADAKAYIL WAS A SLAVE MORE POWERFUL THAN THE MIGHTY FU#KIN' CAESAR -- BY LIGHT YEARS .

    this has now passed on to LORE -- never ti happen again in the annals of sea .

    am i boasting ?

    -- so be it !

    humility is NOT about having a low opinion of yourselves to please the JEALOUS party.

    see, this would have been part of my post-- GAMES CAPTAIN PLAYED--

    you made me reveal it prematurely --with your TAMIL PRIDE ! TAKE IT EASY !

    check out my training ship-

    https://www.youtube.com/watch?v=MwpFBPMtnj4

    https://www.youtube.com/watch?v=k0BxC3kFET8

    capt ajit vadakayil
    ..

    ReplyDelete
  4. Capt. Ajit Vadakayil
    October 15, 2014 at 7:00 PM
    STOP PRESS:

    I AM WRITING THIS AS I PROMISED ONE OF MY READERS 45 MINUTES AGO-- HE RAN UP TO ME DURING MY MORNING WALK--

    HE WANTED TO KNOW OUT OF MY 300 PLUS SCOOPS IN MY NEARLY 845 ODD POSTS--WHICH IS NO 1 AND WHICH IS NUMBER 300.

    ############

    well let me make it clear , these 300 scoops are CONSTRUCTIVE SCOOPS .

    all these 300 scoops are in the plane of INVENTION and NOT innovation.

    none of these 300 scoops are DESTRUCTIVE -- so my posts proving that edison, newton, darwin, einstein etc are IDIOTS does not find a place in these scoops.

    so waht could be the no 1 scoop?

    it is about providing a HINT on how to make a astronaut hibernate while travelling to mars -to cut down on food and water .

    it is about keeping alive a seriously wounded soldier till he can find proper medical care.

    punch into Google search-
    HIBERNATION WITH HYDROGEN SULPHIDE GAS VADAKAYIL

    and

    FUMAROLES FOR FREE ENERGY AND HYDROGEN SULPHIDE SUICIDES IN JAPAN VADAKAYIL


    one of my russian chief engineers who lived near siberia , a place infested with HUGE bears had once woken up a bear while on hibernation in a cave ( as a child ) and he told be how furious the animal was. Before they go into months of hibernation they would kill a large animal ( bury the dead animal it in the ground ) and would NOT eat it unless it became putrid , reeking of rotten eggs..

    WELL WHAT WOULD BE NO 300 RANK.

    it is about PIN WORMS on as$hole.

    Check out the comment dated 18th Dec 2013 , about surcharging the anus with oxygen 5 times a day to prevent pinworms disrupting your REM sleep. This is a 6000 year old Ayurvedic cure for pinworm which happens when you eat non-veg heavy meats and do NOT wash your as$hole after a crap.
    Punch into Google search-
    VEDIC PRACTISES IN MECCA VADAKAYIL

    If I were a white JEW, I would have been an international celebrity. but then who cares?

    I have reached a stage where ONLY I can evaluate myself--

    one of my DUTCH bosses tried to patronise me nearly 2 decades ago -- he said he has given me a good confidential service report-

    so i told him something in Hindi -- with its translation.

    VADAKAYIL KHUD QUESTION PAPER SET KARTA HAI !

    VADAKAYIL KUD EXAM LIKTHA HAI !!

    VADAKAYIL KHUD NUMBER DETA HAI !!!

    capt ajit vadakayil sets his own exam question paper, he writes the exam , and then he gives himself the marks .

    THIS IS THE MEANING OF LIBERATION.

    believe me -- that man hugged me ( NO patronising here ) and said -- he expected such an frank retort from me .

    he said- every other captain would have said thank you .

    he was told to enter into this dialogue by the single man owner of that shipping company . this was about my " CUT THE CRAP " EMAILS -- where i would point out that the EMPEROR IS NAKED .

    99% of the people will NOT even understand the wisdom and gravity of the statement above.

    capt ajit vadakayil
    ..

    ReplyDelete