chemical tanker guide
Chemical hazards || Various chemicals || Cargo Stowage || Care ||Tank cleaning ||Handling equipments || Home

chemical tanker navigation at sea
Isocyanates require sophisticated handling for safety, health and loss prevention reasons. They need careful consideration prior loading , tank coating compatibility, cross compatibility with other cargoes carried, special tank cleaning procedures & environmental controls .

Product safety data sheets may be available from various sources. For safety preparation, until the specific product safety data sheet can be obtained, Chemical Data Guide for Bulk Shipment by Water (U.S. DoT), should be used. Concerning the IBC/BCH code (respective 16.2/5.2) the Master should request the specific product safety data sheet before commencement of loading. The safety data sheet posted must be in a language understood by ship's Officers and Crew.

Isocyanates handling special arrangements - Equipment Planning

Preparation before loading A valve must be fitted at each outlet in use so each line can be blown to the tank individually. If this method is used then the ship staff must be completely satisfied with the integrity of all valves on the system. At the end of the loading it must be ensured that no trace of product is left in the lines or cross-overs.

Final loading preparation

Follow procedure in "N2 purging of lines and tanks". Purging will continue until the dew point in the tank has been reached as governed by regulation contained in the IBC/BCH code (minus 40°C.) for dry tank environment. Before commencement of loading, following must be arranged and observed:

After loading A second option is to blow through the lines with Nitrogen and then keep it under Nitrogen pressure for the entire voyage. Nitrogen utilised for this will be on the charterer’s account.

Discharging Isocyanates

  1. The same safety precautions must be taken as during loading.

  2. When discharging, the tank must be inerted with N2 from shore during the entire operation (via the vapour return line). Refer to Section 9.9 of these procedures.

  3. For efficient stripping and line clearing use Nitrogen.

4. If any spill during disconnecting of the shore hose occurs, spray the area immediately with the neutralizer.

Cleaning & slop disposal / Isocyanates - Cleaning from TDI using gas oil

Cleaning from Isocyanates using chlorinated solvents

  1. This cleaning procedure is used when cleaning from Isocyanates such as MDI, PAPI and TDI, with exception (for TDI when using gas oil and fixed tank cleaning machines).

  2. Ensure that the tank lining is resistant to the particular chlorinated solvent being used. (Some coatings e.g. Phenoline and Devchem 253 are not resistant to MEC).

  3. Ensure that the selected chlorinated solvent is handled/stored under dry conditions (e.g., dry lines and storage tank).

  4. The chlorinated solvent should be heated to a point above the melting point of the Isocyanate to be cleaned. Ensure that the temperature of the chlorinated solvent is kept below the boiling point of the selected chlorinated solvent.

  5. Transfer a sufficient quantity (approximately 10 M3) into the tank to be recirculated.

  6. Prior to placing the portable cleaning machines, supply and maintain a positive N2 pressure throughout the cleaning operation. (Closely monitor the pressure).

  7. When re-circulating, via the pump stack or manifold, all tank cleaning machines (as fitted or each section) must be used.

  8. Recirculate the selected chlorinated solvent for a minimum of 2 hours.

  9. Vent line, cargo line, drop line and stripping line must also be flushed with chlorinated solvent as part of the cleaning procedure.

  10. Chlorinated solvent may be reused in additional tanks by repeating the above procedure.

Cleaning from TDI using water

The above procedure has proven to be a useful alternative to Chlorinated Solvent re-circulation when there is time at sea for cleaning.

A sufficient amount of water is the key. Please consider this as if you were using MEC and then cleaning after. If you re-circulated four hours with MEC and washed four hours after that, then you should be washing with water for eight hours. The above procedure shows six hours, this should be the minimum wash time. It is not uncommon to have traces of white powder remaining in shadow areas. These areas should be dealt with immediately using white spirit. One should avoid spraying or wiping with alcohols or ketones, as these will encourage any reaction, making removal more difficult.

Experience has shown when larger amounts of white powder are left over; chlorinated solvent re- circulation will remove any left over areas.

We have summarized below some of the special chemical cargoes frequently carried onboard chemical tankers

Handling benzene & methanol safety precautions

Handling carcinogens requirements for certain chemical cargoes

Handling ACRYLONITRILE safety precautions

handling ISOCYANATES safety precautions

handling Sulfuric acid safety precautions

handling Phenol safety precautions

Requirements of various grade chemical cargo heating

Handling benzene & methanol safety precautions

Personal protective equipments for carcinogens & cyanide-like cargoes onboard chemical tankers

Following detail pages explain all liquid chemical hazards & precautionary measures while carrying at sea.

  1. Toxicology and associated hazards onboard chemical tankers
  2. Hazards of vapour given off by a flammable liquid while carrying at sea
  3. Reactivity of various noxious liquid chemicals
  4. Most corrosive chemicals carried onboard chemical tankers
  5. What is putrefaction process of liquid chemicals ?
  6. Specific gravity,Vapour pressure and boiling point,Electrostatic charging & measuring Viscosity
  7. General precautions onboard chemical tankers
  8. Mooring precautions onboard chemical tankers
  9. Berth precautions onboard chemical tankers
  10. Cold weather countermeasures, avoiding electric storms
  11. Restriction on using radio equipments and other mobile devices in cargo working areas
  12. Handling precautions for carcinogens or cyanide-like substances
  13. Means of access (gangways or accommodation ladders) safety precautions
  14. Preparations for hot work and safety precautions
  15. Precautions against static electricity

Following reference publications provide useful guidance and international regulations for carrying hazardous chemicals at sea.

Main Info pages!

Home page ||| Chemical hazards ||| Cargo planning & Stowage ||| Cargo loading ||| Cargo documents ||| Safe stability ||| Cargo care ||| Preparation for unloading ||| Inert gas systems |||Gas freeing ||| Nitrogen handling ||| Chemical handling Safe practice |||Handling equipments ||| Cargo & Ballast pumps ||| Cargo tanks |||Tank cleaning |||Special cargoes |||Spills emergencies |||Fire protection is merely an informational site about various aspects of chemical tankers and safety tips that may be particular value to those working in: Chemical Handling, Chemical Storage, Liquefied Chemical Suppliers, Chemical Shipping, Chemical Transportation, Chemical Terminals, Bulk Chemical Services and Chemical Processing. If you are interested in finding out more about chemical tanker guideline please visit IMO official website. For any comment please Contact us

Copyright © 2011 Chemical Tanker All rights reserved.