Chemical Tanker Notes i Witherby Seamanship International Ltd. Captain Vladimir Kunichkin A Witherby Seamanship Publication Chemical Tanker Notes ii Vladimir Kunichkin Captain Vladimir Kunichkin has more than 30 years of experience on oil and chemical tankers, working his way through the ranks until achieving the position of Master with Knud I. Larsen Ship Management. A strong interest in seafarer training led Vladimir to the position of training officer at the “LAPA” centre, specialising in training senior officers in chemical tanker operations. Captain Kunichkin now holds the position of training manager with Tesma. Chemical Tanker Notes v Table Of Contents 1 The Voyage....................................................................................................1 1.1 Voyage Orders................................................................................................1 1.2 Voyage Planning.............................................................................................1 1.3 Stowage Planning............................................................................................3 1.4 Notice of Readiness......................................................................................22 2 Tank Cleaning..............................................................................................23 2.1 Cleaning and Disposal Procedures...............................................................23 2.2 Cleaning Methods..........................................................................................28 2.3 Cleaning........................................................................................................30 2.4 Planning Tank Cleaning Operations..............................................................42 2.5 Overhaul and Tests.......................................................................................45 2.6 Team Briefing................................................................................................48 2.7 Precautions Against Unauthorised Discharge...............................................48 2.8 Safe Cleaning................................................................................................49 2.9 Visual Inspection of the Tank.........................................................................53 2.10 Wallwash Tests.............................................................................................55 2.11 Preload Tests................................................................................................59 2.12 Notice of Readiness......................................................................................64 3 Loading........................................................................................................68 3.1 Safety Precautions........................................................................................68 3.2 Transportation Requirements........................................................................74 3.3 Tanks Inspection...........................................................................................85 3.4 Safety and Data Sheet..................................................................................88 3.5 Loading and Deballasting..............................................................................89 3.6 Cargo Tank Vapour Return Systems.............................................................92 3.7 Loading Rate.................................................................................................94 3.8 Loading Temperature....................................................................................95 3.9 Sampling.......................................................................................................95 3.10 Cargo Calculation..........................................................................................97 3.11 Disconnection of Manifolds..........................................................................101 3.12 Cargo Discrepancy......................................................................................102 3.13 Short Loading..............................................................................................104 3.14 Letter of Authorisation.................................................................................105 3.15 Bill of Lading................................................................................................106 3.16 Time Sheet..................................................................................................106 3.17 Loading Set of Cargo Documents................................................................108 4 Departure...................................................................................................109 5 Conditions of Carriage..............................................................................110 5.1 Heated Cargo..............................................................................................113 5.2 Nitrogen Blanket Cargo...............................................................................115 5.3 Re-circulation...............................................................................................116 5.4 Inhibited Cargoes........................................................................................116 Chemical Tanker Notes vi 6 Arrival at Discharge Port..........................................................................118 6.1 Reducers.....................................................................................................118 6.2 Samples......................................................................................................118 6.3 Bill of Lading................................................................................................119 6.4 Cargo Measurement and Calculation..........................................................119 6.5 Claims.........................................................................................................119 6.6 Safety Precautions......................................................................................119 6.7 Discharging Plan.........................................................................................122 6.8 Palm Oil.......................................................................................................122 6.9 Paraffin Wax, Slack Wax.............................................................................122 7 Discharging................................................................................................123 7.1 Pumps.........................................................................................................123 7.2 Commencing Discharge..............................................................................129 7.3 Main Discharge............................................................................................131 7.4 Stripping......................................................................................................132 7.5 Blowing the Line..........................................................................................134 7.6 Inspection....................................................................................................135 7.7 Bill of Lading................................................................................................135 8 Ballasting...................................................................................................136 8.1 Ballast Eductors...........................................................................................136 9 Prewash......................................................................................................138 9.1 New Ships...................................................................................................138 9.2 Existing Ships..............................................................................................139 9.3 Procedures..................................................................................................142 9.4 Inert Gas Generator.....................................................................................145 10 Terms and Definitions...............................................................................147 Appendices...........................................................................................................151 Appendix 1 Compatibility Chart........................................................................152 Appendix 2 Alphabetical Listing of Compounds...............................................153 Appendix 3 Exceptions to the Compatibility Chart............................................174 Appendix 4 Exceptions to the Compatibility Chart............................................176 Appendix 5 FOSFA List of Banned Immediate Previous Cargoes...................178 Appendix 6 FOSFA List of Acceptable Previous Cargoes................................180 Appendix 7 World Chemical Trade...................................................................183 Appendix 8 International Certificate of Fitness for the Carriage of Dangerous Chemicals in Bulk...................................................................................................185 Appendix 9 NLS Certificate..............................................................................191 Appendix 10 Procedures and Arrangements Manual.........................................194 Appendix 11 Cargo Record Book.......................................................................211 Appendix 12 Cargo Hose Record.......................................................................215 Appendix 13 Shipboard Marine Pollution Emergency Plan (SMPEP)...............217 Appendix 14 Guidelines in developing a SMPEP...............................................218 Bibliography.........................................................................................................229 Index......................................................................................................................230 Chemical Tanker Notes Discharging 123 7 Discharging The vessel’s discharge performance is affected by the following: • Type of cargo pump • density and viscosity of the cargo • limitations established by the receiver • back-pressure from the shore • diameter of the shore line • length of the shore line • elevation if the shore tanks • availability of booster pumps ashore and their capacity rate • level of cargo in the ship’s tank. 7.1 Pumps The two types of pumps that are installed on chemical tankers are positive displacement pumps and kinetic or centrifugal pumps. 7.1.1 Displacement Pumps Displacement pumps function by displacement of the liquid inside the pump. Examples include the piston pump and the screw pump. A pipeline system equipped with displacement pumps must have a safety valve and bypass line to protect the discharge line. Piston pumps and screw pumps have excellent suction properties, but any deterioration of the cargo pipework will cause a reduction in the discharge rate. Displacement pumps are allocated to groups of tanks, normally one pump per group. The suction and discharge valves of a positive displacement pump must always be open before starting the pump and must remain open until it is stopped. Activation of the over-speed trip of these pumps must be avoided and particular care and attention must be taken when the cargo level in the tank is reduced to the final 0.5m of liquid. At this point the pump’s speed should be reduced. Figure 7.1 - Displacement Pump Reproduced with permission from Allweiler AG Chemical Tanker Notes Discharging 124 Figure 7.2 - Pump Comparison Chart Reproduced with permission from Allweiler AG 7.1.2 Submerged Deepwell Pumps Submerged pumps are used when an individual pump is required in each cargo tank. These pumps will be either hydraulically operated or electrically powered. Photograph 7.1 - Hydraulically Operated Submerged Pump Photograph 7.2 - Electrically Operated Submerged Pump Chemical Tanker Notes Discharging 125 Figure 7.3 - Submerged Pump Reproduced with Permission from Marflex BV A good example of a submerged pump is the Marflex deepwell pump, shown in Figure 7.3. This is driven by an electrical motor. It has an ‘oil lubricated shaft’ that runs in a separate support pipe. The service life of an oil lubricated shaft is estimated at more than 10,000 running hours, based upon the service life of the bearings and the motor, and this is deemed sufficient for the 20-25 years life of a chemical tanker. Chemical Tanker Notes Discharging 126 7.1.2.1 Deck Arrangement of submerged pumps: Figure 7.4 - Submerged Pump Deck Arrangement Reproduced with permission from Marflex BV 95% of the submerged deepwell pumps that are installed by Marflex BV are electrically driven. This is because they have found that: • The system efficiency is 20% higher • noise levels are lower • electrical wiring is easier to install rather than complicated hydraulics, therefore commissioning time is substantially reduced • it has a clean external system with no hydraulic leakages • there is a reduction in the need for maintenance. 7.1.2.2 Pipe Stack Arrangement of Submerged Pumps The pump stack (figure 7.6) contains two pipes. One is the discharge pipe for the cargo and the other is an enclosure for the intermediate drive shaft, shaft bearings and lubricating oil. As the drive shaft is oil lubricated, the pump can run at relatively high speeds and will not run dry during cargo stripping or tank cleaning operations.