Pioneering Fouling Management in the LNG Industry: Plant Cooling Seawater System and Carrier Hulls. February 2008

Transcription

1 Pioneering Fouling Management in the LNG Industry: Plant Cooling Seawater System and Carrier Hulls February 2008

2 Presentation overview Qatargas Fouling Issues Regulatory Issues SCENR IMO Plant Cooling Seawater System Old chlorine dosing philosophy Pulse-Chlorination Future monitoring LNG Carrier Hull fouling protection A note on Qatargas current BWM 2

3 Qatargas Fouling Issues Qatargas use sodium hypochlorite from onsite ECP to treat ~110,000 m 3 / hr of seawater Qatargas has had minimal direct disturbance of plant operations from biological fouling Maintenance and cleaning of seawater intake and occasional strainer / heat exchanger increasing LNG carriers previously had TBT based paint with 3 year dry dock schedule 3

4 Qatargas Regulatory Issues SCENR requiring less chlorine discharged to sea April 07 new Qatari environmental law requires 0.05 mg / L Free Residual Chlorine April 07 new World Bank / IFC guideline of 0.2 mg / L Total Residual Oxidant IMO requiring abandonment of TBT based paint usage November 07 ROPME Sea Area designated Sensitive under MARPOL 73/78 No ROPME states ratified Annex VI 4

5 Why regulate residual oxidants (chlorine) Why are the residual oxidant standards an important environmental issue? Protect local marine resources (e.g., sea grass beds, coral and fish communities) Other users : Industrial / commercial / recreational Reduction in the TRO (including Chlorination By-Product) content of cooling seawater discharged significantly improves quality of life for all communities Qatargas strategy = combining optimal fouling control with minimal chlorine discharge, while retaining safe plant operation Chlorination of seawater is the most applied method for oncethrough cooling water systems 5

6 Chlorination in seawater Continuous and Shock Chlorination Concentration n Time 6

7 Fouling examples Increased protection from fouling blocked strainers with high P 7

8 Pulse-Chlorination background European Commission (2000) Best Available Technique (BAT) Pattern of old continuous and shock dosing versus new Pulse-chlorination technique (in red) Improved efficacy > 50% Cl - reduction Less TRO discharged Less CBP formed Reduced ECP maintenance ECP mothball (?) Concentration Time 8

9 Fouling examples Increased protection from fouling 9

10 Pulse-Chlorination at Qatargas: on-site lab 10

11 Pulse-Chlorination Calculated saving of 56% chlorine added to sea Originally 6162 kg /day now 2664 kg / day Winter months expected to show greater benefit Continued improvement of cooling seawater system chlorination and science-based decisions 11

12 Looking forward: monitoring Spat fall of oysters Biofilm development EcoReefs 12

13 LNG Carrier fouling LNG fleet 10 Moss-Rosenberg spherical-type carriers (135,000 m 3 LNG capacity) on long term trade to Japan, plus 2 vessels (135,000 m 3 and 125,000 m 3 ) for medium term trade to Spain. Intersleek silicon-based paint 1 st applied 2001 to the Japan trade vessels Initial application doubled the time required in drydock but for future drydocks, the time was substantially reduced as no re-coating was required for 5 years, other than minor repairs to areas which had suffered mechanical damages. Operational and environmental benefits Reduced drag More cost effective transport t (fuel consumption) while reducing emissions i per journey due to the lower frictional resistance of the silicon based coating and the lack of hull fouling. Reduced dry-docking Reduced waste produced / maintenance costs per carrier Increased carrier cargo delivery potential No TBT, in favour of high performance Silicon or Copper based coatings. 13

14 LNG Carrier fouling LNG carriers with silicon-based paint have only faced one case of serioud fouling (in Singapore) no re-coating was required 14

15 LNG Carrier fouling Propeller growth 15

16 LNG Carrier fouling Propeller growth 16

17 LNG Carrier fouling Barnacle growth 17

18 LNG Carrier fouling Hull growth of tube worms 18

19 LNG Carrier ballast water management Ras Laffan Port ballast water and sediment management strategy under development through RLC / Qatar Petroleum and the State of Qatar Qatargas is single operator for all port product activities Ballast sediment management issues important (Mimura et al., 2005) Qatargas Conventional LNG fleet 163,000 m 3 ballast exchanged per vessel per Conventional vessel delivery, based on 3 ballast loading/discharge operations per voyage. LNG : ballast water ratio of 1 : 1.2 IMO ballast water exchange standard followed Studied using satellite tracking (Kozai et al., 2006) Green Award being pursued by Qatargas to enhance the environmental image of LNG transportation. Green Passport already adopted for several vessels in the Japanese trade and being pursued fleet wide 19

20 LNG Carrier future fleet 45 New LNG carriers similar sizes to VLCC have been specifically designed (Q-Flex and Q-Max) that have operational and environmental benefits due to economies of scale Increased LNG capacity by > 50% More cost effective transport (fuel consumption) while reducing energy requirements by 30-40% BOG recovery Reduced VOC emissions while increased cargo delivery Q-Flex (~210,000 m 3 LNG) 211,000 m 3 ballast exchanged per delivery based on three loadings/discharges of ballast per voyage (Ratio 1 : 1) Q-Max (~265,000 m 3 LNG) 270,000 m 3 ballast exchanged per delivery based on three ballast loadings/discharges per voyage (Ratio 1 : 1) 20

21 LNG Carrier future fleet Q-Flex 21

22 22 Thank you