INTERTANKO GAS FORUM Athens 8th of June 2016

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Bethanie Norris
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1 INTERTANKO GAS FORUM Athens 8 th of June 2016

2 Co-Mingling of Cargoes on LPG Vessels BACKGROUND TO CO-MINGLING SOLAS REGULATION Discussion Points REASONS FOR CO-MINGLING CO-MINGLING ON DIFFERENT LPG VESSELS HAZARDS OF CO-MINGLING COMMERCIAL IMPLICATIONS 2

3 Background of the Evolution of Co-Mingling Guidelines In 2005 the United Kingdom reached out to the Evaluation of Safety & Pollution Hazards Committee (ESPH), seeking guidelines on Bio-Fuel Carriage. In turn, ESPH deferred the matter to IMO s Bulk Liquids & Gasses sub-committee (BLG). It was only in 2009 (BLG 13) that blending of Bio-Fuels was seriously considered. The BLG submitted to MSC and MEPC, that blending practice At Sea should be prohibited and guidelines for In Port Operations to be developed. 3

4 Background of the Evolution of Co-Mingling Guidelines In June 2009, MSC-MEPC (Circ.8) issues guidance where in Prohibition of Blending of MARPOL cargoes on board during the Sea Voyage was published. In 2010, the Evaluation of Safety & Pollution Hazards Committee (ESPH) proposes that the new regulation should be part of SOLAS as physical blending was related to Safety. In 2012, at MSC 90, it is agreed to adopt IMO Resolution MSC.325(90), prohibiting blending of Bulk Liquid Cargoes, whilst at Sea. 4

5 SOLAS Regulation Jan 2014 : SOLAS Ch. VI/Reg 5-2, is amended to incorporate IMO Resolution MSC.325 (90). Regulation reads as follows: Prohibition of the blending of bulk liquid cargoes and production processes during sea voyages The physical blending of bulk liquid cargoes during sea voyages is prohibited. Physical blending refers to the process whereby the ship's cargo pumps and pipelines are used to internally circulate two or more different cargoes with the intent to achieve a cargo with a new product designation. This prohibition does not preclude the master from undertaking cargo transfers for the safety of the ship or protection of the marine environment. 5

6 SOLAS Regulation - Questions being Asked In June 2014 at MSC 93 - Members sought answers to the following Questions: 1. What is the definition of Sea voyage"? (When a vessel located outside port limits. Port limits being defined as per the Port Authority) 2. The meaning of Product Designation? (New end product which varies in specs from the original) 3. The application to the carriage of LPG? Yes such carriage falls under the ambit of Bulk Liquid cargoes. 6

7 Reasons for Co-Mingling Butane/Propane COMMERCIAL Tax Purposes. Reduction in import duty of the LPG Mix, if this will be undertaken prior arrival territorial waters typically in countries like India, Turkey. Avoid the extra Cost and Time for mixing both the products ashore. LOGISTICAL In countries where the ambient temperature fall below zero (near to Butane s Boiling Point) the Butane as fuel gas has a serious limitation as vapour cannot be generated. Quicker turnaround of the cargo being imported, as the LPG mix would be directly fed to the plants. 7

8 Mixing Ratio vs SVP 8

9 Co-Mingling on Different LPG Vessels On board Fully Pressurized (M.A.R.V.S 18 barg) vessels: Not a concern. Ships Tanks are designed to withstand the pressure of all cargoes they are carrying at ambient temperature. On board Semi- Pressurized (M.A.R.V.S 5-8 barg) vessels: Is not a Major Safety issue, although the relief valve settings can vary and the pressure of the resultant mix could exceed the MARVS setting. On board a Fully Refrigerated (M.A.R.V.S 0.4 barg) vessels: Can cause Major Concerns as Ships Tanks do not have pressure capabilities to carry cargo at ambient temperature but only in it s boiling point with very small marginal range. 9

10 Hazards Associated with the Co-Mingling Process Co-mingling Process 1. Experience: Safety concerns as the instructions to co-mingle LPG cargoes do not take into account the experience of those on board or those issuing such instructions. 2. Uncontrolled Venting: Mixing fully refrigerated Butane with fully refrigerated Propane generates a large amount of Flash Gas 3. Rollover : It can occur when the Propane (lighter) and the Butane (heavier) are mixed in the same tank and hence layers being created of different density. This is termed as stratification. 10

11 Hazards Associated with the Co-Mingling Process 4. Loss of Power: Compressor capability will be compromised and there would be no contingency for disposal of the vapour generated unless a vapour return line was fitted alongside the Terminal. 5. Stability and stress issues : When blending the vessel will at all times have at least two tanks slack this can result in reduced stability of the vessel due to free surface effects. 6. Quick Cool Down: Thermal stresses can accumulate. 7. Sloshing Effect: Slack tanks can cause sloshing effect that could damage the cargo fittings inside the tanks and also could lead to sudden rise in tank pressure. 11

12 Commercial Implications of Co-mingling Load Suitability: The LPG Mix remaining after discharge may not be suitable for loading the next grade. Cargo Quantification: After the co-mingling operation the density of the mixture will not be a mathematical average of the two cargoes because the molecular composition will be different. Legality: Operations undertaken in disregard with SOLAS requirements will prejudice P&I cover. 12

13 Way Forward Formulation of the Intertanko Gas Tanker Committee on Feb Guidelines for Commingling of LPG Cargoes on board Gas Carriers under process. 13

14 Consolidated Marine Management Inc. 4 Xenias Str. Kefalari-Kifisia Greece Thank you.

INTERTANKO GUIDE TO BLENDING/COMMINGLING OF LPG CARGOES ON BOARD GAS CARRIERS

INTERTANKO GUIDE TO BLENDING/COMMINGLING OF LPG CARGOES ON BOARD GAS CARRIERS Blending/Commingling of LPG Cargoes On Board Gas Carriers By INTERTANKO s Gas Tanker Committee All rights reserved. No part