Friday, November 19, 2010

PHENOL ON CHEMICAL TANKERS-- CAPT AJIT VADAKAYIL

                     

PHENOL ON CHEMICAL TANKERS


During loading operations in cold weather , PHENOL vapour will be released into the atmosphere during loading and can fall as snow and you need a stout heart under your PPE.

In the Auschwitz concentration during world war II , camp prisoners were exterminated by phenol injections (Abspritzen) straight into the heart.

If Phenol falls on 4 square inches of your skin you may die within 30 minutes to several hours.

During the delay there will be gradual damage to kidneys, liver, pancreas, spleen, with edema of lungs. There may be burning pain, pallor, sweating, weakness, dark urine, tremors, twitches, vomitting, ringing in ears, fall of body temp , mental confusion, vertigo and shock.

It is thus important to reassure the unfortunate casuality, who has not worn proper PPE.

Loading Phenol from barges especially in freezing temperatures is a huge risk. The reason is that the cargo is highly poisonous and can freeze in the pipelines because its MP is 40.6 deg C and cargo solidifies.  If you allow the cargo to freeze in the pipelines you expose your crew to Phenol and you have failed in your duty. Any stoppages of cargo due to the barge doing internal stripping , barge change over etc must be known to you. You must remember it is easier to blow by assistance of gravity than against the trim uphill when the nitrogen blow will skim over the cargo and cool and freeze it.

When trying to blow through and clear the frozen lines  SAFETY FIRST is the watchword. Don’t try to save time at the expense of crew safety. Everything must be planned. Before you put your hands into motion put your brain in gear.

If the pipelines freeze it is easier to apply very hot water (95C) externally especially at bends. Application of steam externally is too local and will take too long. You cannot blow with steam internally as the cargo is moisture sensitive. It is a good idea to have steam copper tubes for thermal tracing of pipelines , especially the manifold common collector. If you cant steam trace the common collector do NOT use it.

Used to manufacture antiseptic, disinfectants, slimicides, mouth wash, sore throat lozenges etc

Properties:

Old name/ carbolic acid
Aromatic alcohol
Clear pink colour
Sweet sickening tarry odour
CHRIS/ PHN
Marpol category/ Y
USCG/ 21
MP/ 40.6C
VP/ 3.07 mm HG @50C
VD/ 3.24
SG/ 1.07
BP/ 182C
Visc/ 4mPas @45C
VH/ 50C
AH/ 60C
DH/ 55C
AIT/ 715C
FP/ 85C
Flammable limits/ 1.7 to 8.6
Absorbs water from air
Soluble in ethanol and ether.
Antidote/ PEG polyethylene glycol (for skin) or 70:30 PEG / methylated spirit mixture swab with cotton.
Combustible
Nitrogen / yes
TLV/ 5 ppm
Odour threshold/ 1 ppm
Soluble in water completely at 60C
Surface tension / high-40.9 dynes/ cm @20C
Good cargo if next cargo is WW
Air and moisture sensitive
Highly poisonous.
Liquid turns red if not perfectly pure or under influence of light.
Sensitive to sudden heat adjustments, may form tarry deposits and become discoloured.
When heated emits toxic and irritating fumes.
Corrosive to skin and respiratory tract.
Poisonous through skin contact. Will give severe burns.
Vapors affects nervous system.


Emergency first aid procedures

Sufficient Drager tubes  (order number 81 01641) must be available before PHENOL is loaded.
Neoprene gloves are resistant.

Chemical antidote/ POLYETHYLENE GLYCOL should be swabbed liberally onto the affected area. the emergency shower must be used, with the patient remaining in the shower for at least 5 minutes. 

MSDS sheets must be posted and non-essential personnel must be kept clear of the operating area and taped off.  Access to the vessel should be from behind the manifold and all persons must be made aware that PHENOL operations are to be conducted. 

Preparation For Loading

Remove flame screens if fitted , for vapors can condense and solidify.

Prior to arriving in the load port, the tanks to be utilized for the carriage of PHENOL must be cleaned for Water White Standard and its pH must be between 6 and 8.  All hose/pipe connections must be pressure tested before commencing any operations to ensure connections are tight. The tank and lines must be dry and odourfree. All joints must be of PTFE and all leaks rectified before commencing cargo operations. Heating coils must be tested and lof entry made. Loading PHENOL is a closed operation. When configuring lines for loading PHENOL, facilities must be available at the manifold to blow nitrogen through all lines used and back into all tanks loaded.
Tanks to be loaded should have ballast removed from underneath and heating coils must be opened once product has fully covered the coils. The PHENOL must be carried at temperatures within charterers instructions, typically between +45 and + 60 degrees centigrade. If cargo is presented at the discharge port at a temperature greater than 10 oC above the freezing point, then there will be no need to undertake pre-washing . A full cargo heating log must be maintained.

The fire main must be pressurized throughout, with monitors/hoses ready at all times. 

Restrict personnel on deck.          

Loading

Once loading has commenced, it must not be interrupted unless absolutely essential. If  loading is interrupted, lines must be blown immediately. Rates to individual tanks should be adjusted to facilitate quick and effective topping off, without risk to personnel.

Venting

As PHENOL freezes at +40oC, personnel must be aware that there is a possibility that vent lines may become blocked should the vapour freeze. During loading operations, PHENOL vapour will be released into the atmosphere during loading and can fall as snow. Depending on wind direction and strength, there will always be a real risk that PHENOL may be deposited over a large area of the vessel.

Topping Off

Wherever possible, tanks being loaded must be topped off  as quickly as possible in sequence to prevent lines freezing. Loading rates to each tank must be adjusted to minimize the chances of product freezing in the lines before they can be blown.

Line Blowing

If lines have to be blown uphill it is better to steam trace the lines in freezing weather.
A major factor in safe and efficient PHENOL operations is the correct and effective blowing of cargo lines upon completion of loading.  High pressure nitrogen must be prepared well in advance of anticipated need. Once tanks have been loaded, manifold valves should be shut and the nitrogen line connected. The nitrogen supply should be opened and pressure allowed to build up. At no time should pressure exceed the safe working pressure of flexible hoses/pipes. Once a sufficient pressure (typically  >7 bar) has been achieved,  the manifold valve for the line to be blown should be slowly opened until the nitrogen starts to move into the line. The manifold valve must not be opened any further. The noise of the high pressure nitrogen should be heard, along with the sound of the liquid phenol, being forced back into the tank. The manifold valve should not be opened fully. Once the pressure has been released, the manifold valve should be closed and the process resumed. This controlled blowing must be conducted until the line to the tank is free from PHENOL. It may well take some 10/15 minutes of blowing each line until the chief officer is completely satisfied that the line are clear. The lines can be tapped using a small hammer or spanner. If a clear bell type ring is heard, then the lines should be clear. A dull “thud” indicates that Phenol is in the line and may already be frozen.  Note, the opposite side (of manifold crossover) to loading connection will be solidified and must be externally heated.

Carriage and heating

Once the lines have been blown, hoses can be disconnected and blanked. During the loaded voyage, flexible hoses should be disconnected and steamed, along with “Y” pieces and reducers.

If no specific heating instructions are supplied, the cargo should be kept at a temperature of approximately +55oC, or advice sought from the office.

The PHENOL must be carried at temperatures within charterers instructions, typically between +50 and + 60 degrees centigrade. If cargo is presented at the discharge port at a temperature greater than 10 oC above the MP, then there will be no need to undertake pre-washing .  A cargo heating log must be maintained.

Normally Phenol heating is carried out by means of thermal oil ( to avoid toxic chemical entering the boiler ) or hot water heating with max inlet temperature of 80 °C. If vessel is not equipped with thermal oil heating system, the steam heating system is to be re-arranged in order to heat the cargo by hot water without send the return steam back to the engine room hotwell.

ENSURE THAT THE COILS CONTAIN ONLY WATER BY KEEPING THE COIL INLET VALVE FULLY OPEN AND ADJUSTING THE RETURN VALVE TO CONTROL HEAT OF WATER IN THE COILS. THE RETURN WATER MUST BE SENT TO ANOTHER DEDICATED TOXIC CHECK FW TANK.

Arrangement--
fresh water tank – butterworth pump – butterworth heater – steam inlet line-   heating coils via portable manifold  – steam return line – back into the same fresh water tank.

Preparation for Discharge

Prior to arrival at the discharge port, the tanks should be configured for effective discharge, again ensuring that adequate blowing points are available. All connections must be pressure tested for leaks and should any be found, the leaks rectified and the system integrity proven. Complete protective clothing is again required, as it is for all PHENOL operations. As a product, phenol requires closed loading/discharging.

Before commencing discharge, the receivers, or their representative must ensure that adequate  tank space is available for the complete cargo. Purge framo pump cofferdam. Once discharge has commenced, the vessel should discharge all tanks without stopping. It should be remembered that, given its high freezing point (+40oC), every effort should be made to ensure that tanks are completed as close together as practical/possible, to reduce the chance of product freezing in the lines, before air can be used to clear the lines back to the tanks. Ullages and individual tank rates must be monitored at frequent intervals, with pump speeds adjusted as necessary.

Discharging

Due to its high freezing point, vapour lines, pressure/vacuum valves, pumpstack valves and deck tank sumps etc. may be blocked due to frozen product. Care must be taken during the initial stages of discharge to ensure that all are unblocked by applying either external live steam or hot water and then;

Product is moving and being discharged.
Tank ventilation is effective for the discharge rate. If there is any doubt, the discharge rate should be slowed down. If discharge has to be stopped, then as mentioned dry air or nitrogen must be available immediately to blow and clear lines.

The fire main is to be pressurized before commencing discharge and throughout all cargo/tank cleaning operations. The anchor cables can be used to bleed pressure, whilst the system is in standby. Foam/water cannons are to be directed over the cargo handling/ manifold area throughout the operation.

If the cargo is to be discharged in parcels, then the following precautions must be made, prior to completing a parcel.

Nitrogen  must be available to immediately blow all lines back to the tank(s) being discharged. Lines must be blown until the Chief officer is satisfied that the lines are clear.

Upon completion of a tank/cargo, a tank dry certificate must be issued immediately, due notice must be given to the receiver’s representative to ensure that he/she is on board and in position prior to completion of cargo.

The minimum number of tanks and lines to be used for each parcel.
Once the tank dry certificate has been issued, lines must be blown until the chief officer is completely satisfied that the lines are clear.

DURING LINE BLOWING OPERATIONS, ALL NON ESSENTIAL PERSONNEL SHOULD BE PROHIBITED FROM ACCESS TO THE DECK AND ALL PERSONNEL ENGAGED IN PHENOL OPERATIONS MUST WEAR FULL PROTECTIVE CLOTHING AT ALL TIMES. IT SHOULD BE REMEMBERED THAT DURING LINE BLOWING, PHENOL CAN BE BLOWN INTO THE AIR, WITH THE RESULT THAT IT WILL FALL AS SNOW. EXTREME CARE MUST BE TAKEN AT ALL TIMES. Upon completion of blowing, the immediate area should be drenched with sea water to wash away any residual product that may remain.

Water should be introduced in to the empty tank as soon as possible to sufficiently cover the heating coils. This can be done by either using a fire hose  (WITHOUT A NOZZLE) or a butterworth machine (WITHOUT A TANK WASHING MACHINE). Once the water is in the tanks and covering the coils, the coils are to be opened. This will have two effects.

Any ROB will be diluted to commence reducing the adverse effects of the cargo and to reduce it’s freezing point.

The diluted product will be heated to avoid any freezing of pump sumps and lines, which will enable tank cleaning operations to be carried out. 

EXTREME CARE MUST BE TAKEN WHEN OPENING ANY ACCESS TO A TANK WHICH HAS HELD PHENOL.  ALL PERSONNEL ENGAGED IN PHENOL OPERATIONS MUST AT ALL TIMES WEAR FULL PROTECTION.

*N.B./ It has been reported that an exposed area of less than 2 square inches can be fatal!

Should there be a major leakage, the area should be drenched by using the water cannon. Shore Authorities should be advised if a major spillage occurs.

Pre-Washing

PHENOL is a category “Y” substance and not to be pre-washed as long as the dischg heat is greater than MP+10C.

Procedures for pre-washing are as follows.

On completion of discharge, tank dry certificate to be issued by receivers.

Water washing temperature to be at least +60°C. (PHENOL becomes  miscible in water at +60°C).  Use water as per P&A manual. USE FW.

Washings to be transferred to shore reception facilities. (Pre-washing slops can be transferred to a nominated temporary slop tank whilst reception facilities are being prepared).

Once pre-washing has been completed, the Cargo Record Book must be endorsed properly, or a certificate  attached to the relevant page.

Tank Cleaning

Use hot sea water at 75C for two hours.
Fresh water rinse
One hour of steaming.
Vent, mop and dry.
Blow all heating coils.

A tank entry certificate must be completed before any entry into a cargo tank.

Phenol will form crystals in vent stacks and PV valves, steam it away.


CAPT AJIT VADAKAYIL ( 28 YEARS IN COMMAND )
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4 comments:

  1. Dear Captain,

    Please may I have you email address.

    Kind regards,

    capt A R Brink
    allen@arbrink.com

    ReplyDelete
  2. hi capt brink,

    just saw your comment. i am about to travel. will be back after 4 months--

    capt ajit vadakayil

    ReplyDelete
  3. Dear captain ~
    Could u pls let me know what's mean VH/ 50C, AH/ 60C, DH/ 55C ??

    ReplyDelete
    Replies
    1. hi ,

      VH-- voyage heat of cargo in tank ( max ).
      AH- adjacent tank cargo heat ( max )
      DH- discharge heat of cargo from tank ( min )

      capt ajit vadakayil
      ..

      Delete