Don’t depend on past observe ( of outdated timers ) , to find out if Tall oil requires a pre-wash ashore after discharge .
As you already know since 1st Jan 2007—the Marpol prewash rules for high viscosity oils have modified. It is best to get the unloading temperature and the viscosity of Tall oil at that temperature declared in writing in a correct signed and sealed document .
Ideally the viscocity in mPas at 20 deg C ought to be declared in the B/ lading —as this determine varies Tremendously relying on the solution percentage of rosins , fatty oils , sterols, alcohols and many others (or is deliberately fudged).
Tall oil is an oxidising , drying oil. Oxidation occurs in 3 phases, liquid, gum and solid.
Tall oil is a spent black liquid from the pulping course of whose composition and properties can range vastly making it crucial to get specs from shippers prior loading or planning stow.
It might be crude tall oil, distilled tall oil, tall oil fatty acid ( liquid rosin, talleol, tallol )—-. It is often used as paint base .
Chris code/ OTL
USCG group/ 34
Marpol cat/ Y
Viscocity at 20C/ 400 mPas ( for CTO forty% soln )
VP/ 3mm Hg at 200 C
Water solubility/ negligible
SG at 20C/ zero.95
FP/ 200 deg C
VH/ will depend on MP—keep 20C above MP
Heating instruction for VH/ DH/ AH and recirc to keep away from sediments should be obtained in writing or the consignee might declare for off spec cargo.
If charterer needs NIL VH –from your facet you simply be sure that the cargo Must stay sufficiently above MP throughout voyage.
Bad earlier cargo for WWT or UV/ PTT
Clear with chilly water for forty five min as it’s a drying oil , then at 75C scorching wash with gracco injection of caustic/ alkaline cleaner.
Oxidation occurs in 3 phases—liquid , gum and solid. So clear tank asap or keep it wet. Drying oil –reacts with water hardness compounds.
If there is any leak on cargo transfer system, cease the transfer and empty the line system. Enable the product to solidify. Include and sweep up, put the substance in an sufficient container for later removing.
For cleansing purposes ensure to have on board ample caustic flakes (roughly 150 kg for a 1000 M3 tank).
As quickly as loading is completed clear the lines to prevent solidification
Cargo heating logs have to be be maintained
When commencing tank cleaning, machine wash the tank(s) sizzling (80C-85C) for six hours at brief drops.
On completion of washing fresh water rinse and strip.
Methodology : Recirc with sturdy caustic solution to saponify ( 10 kg in one hundred litres of recent water ratio) at 45 C one hour at every brief dropcomplete 6 drops.—with heating coils running. Give a brief FW rinse . SS tank could be refreshed with weak Metalbrite if next cargo is sensitive.
Then wash at 40C short drops one hour each 6 drops. –again rinse with FW
Toluene steam cargo traces or you’ll have to flush the traces for too long. Additional cleansing after caustic could be accomplished if required by Myrcene, Coaltar cleaner,
TALL OIL FATTY ACID –is NOT a drying oil like tall oil. It’s a yellow oily liquid with acrid adour. Used as slicing oils, soap, emulsifier, lubricants and many others. very tough to scrub.
MP/ 1C—viscosity varies with heating
FP/ 193 C
Crude tall oil pitch is a semi-drying oil.
Before Handling TALL OIL–You have to Understand What is VISCOSITY
The viscocity of a chemical cargo determines how straightforward it is to pump out the product and the quantity of residue that can be left after discharge .
There are time charterers who will put your ship off rent if you can’t use your deep properly centrifugal pump to discharge viscous cargoes which need a screw pump. After 1.1.07 with Cat Y/Z Marpol classes pre-wash relies on viscosity of cargo at DISCHARGE PORT temperature –it becomes all of the more imperative to know this branch of Physics—how increase in temperature reduces viscosity.
High-Viscosity Substance means a noxious liquid substance in Class X or Y with a viscosity equal to or greater than 50 mPa.s at the unloading temperature.
Excessive viscosity chemical should be PRE-washed with hot water, with chilly interface removed, and the washing discharged to shore reception facilities..
Viscosity is inner resistance of a fluid to movement or a measure of fluid friction—thus water is thin having low viscocity and honey is thick having excessive viscocity.
In a laymans language it is a measure of the flexibility of a liquid to move by means of a hole. (For the highest frequent denominator– The power per unit area needed to shear a fluid is proportional to the velocity gradient. This fixed of proportionality is the viscosity.)
This resistance acts against the movement of any solid object by way of the fluid and likewise in opposition to motion of the fluid itself past stationary obstacles. Viscosity additionally acts internally on the fluid between slower and faster moving adjacent layers.
All fluids, exhibit viscosity to some degree. Viscosity could also be considered fluid friction.
Viscosity diminishes as temperature rises, often by about 2% per degree C.
ThePoiseuille and thePoise are models ofdynamic viscosity generally calledabsolute viscosity.
1 Poiseuille (Pl) = 10 poise (P) = one thousand cP
Phonetically it’s spelledpwaz.Poise (P) named after Jean Loius Marie Poisueuille. It’s extra commonly expressed, significantly in ASTM standards, as centipoise (cP). The centipoise is usually used as a result of water has a viscosity of 1.0020 cP (at 20 °C) 1 poise = one hundred centipoise = 1 g/( cm.s) = 0.1 Pa·s.
1 centipoise = 1 mPa·s.
Screw pumps can handle 1 million mPas or cP.
The “thicker” the fluid, the greater its resistance to shear stress and the more fast the decay of its flow.
The SI physical unit of kinematic viscosity is the (m2/s). The CGS bodily unit for kinematic viscosity is thestokes (abbreviated S or St), named afterGeorge Gabriel Stokes . It is sometimes expressed by way of centistokes (cS or cSt).
1 stokes = a hundred centistokes = 1 cm2/s = zero.0001 m2/s.
Viscosity could be a major factor that affects the value of the Reynolds number.
The Reynolds quantity is the ratio of inertial forces to viscous (drag) forces and is used for determining whether a flow will probably be laminar or turbulent. Laminar flowoccurs at low Reynolds numbers, the place viscous forces are dominant, and is characterized by clean, constant fluid motion, whereas turbulent, on the other hand, occurs at high Reynolds numbers and is dominated by inertial forces, producing random eddies, vortices and different movement fluctuations.
The transition between laminar and turbulent circulate is often indicated by a crucial Reynolds quantity. Within circular pipes the critical Reynolds quantity is generally accepted to be 2300
If we want to calculate the Reynolds quantity , we are able to use the next equation.
R = 3160 x Q x Gt D x µ
the place: R = Reynolds number
Q = liquid’s flow charge, gpm
Gt = liquid’s specific gravity
D = inside pipe diameter, in.
µ = liquid’s viscosity, cp
Crucial velocity= Visc coefficient X RN/ SG X dia
When the Reynolds quantity is less than 2000, move will likely be described as laminar
When the Reynolds quantity is higher than 4000, circulation will probably be described as turbulent
When the Reynolds quantity is within the vary of 2000 to 4000 the circulation is taken into account transitional.
For e.g Chances are you’ll discover highly viscous hydraulic oils could exhibit laminar movement in most situations whereas issues like water will likely be turbulent
NOW Let us DIGRESS Back TO CHEMISTRY
High Viscosity Substance
A substance meets the standards of a high viscosity substance, if the viscosity exceeds a certain restrict, that depends on the Product Group.
Within the previous system ( earlier than 31st Dec 2006 ) if a product was in Category A or B, or Category C and within a particular area and the viscosity at discharge circumstances is higher than or equal to 25 mPa*s, the substance must be handled as high viscosity substance. If the product is Class C and outside of a particular area and the viscosity at discharge circumstances is larger than or equal to 60 mPa*s, the substance needs to be treated as excessive viscosity substance.
In the new system after 1st Jan 2007a high-Viscosity Substance means a noxious liquid substance in Class X or Y with aviscosity equal to or higher than 50 mPa.s at the unloading temperature.
Merchandise with a high viscosity
These merchandise should be washed at larger temperatures. Normally theviscosity is intently related to the temperature and will decrease at higher temperatures. Throughout washing there ought to be no ballast water or chilly cargoes adjoining to the tank to be cleaned. Washing as quickly as potential after discharge is beneficial. The respective product characteristic of the person product have to be noticed.
Cargoes with high viscosity require a better temperature wash water. The wash water then has to be heated to carry the viscocity of the chemical down. Remember the HO bunkers taken by chief engineer is lowered in viscocity from 380 cst to 15 cst previous to injection into the ME—the heating to be achieved, say upto 135 deg C is understood to him.
Some chemicals like LO additives, veg/ animal oils, polyols and so forth don’t have a defined MP, however a variety. For such cargoes viscocity is used as a measurement of the products liquidity of dealing with characteristics, and the term pour level is used instead.