INNOVATIVE MARINE TERMINAL CONFIGURATIONS

Transcription

1 INNOVATIVE MARINE TERMINAL CONFIGURATIONS Phillip Cox Virginie Lehning Raul Risi Technip France ABSTRACT The significant increase in LNG production, both present and future has seen the need for larger and more efficient Marine facilities for LNG Terminals. Such Marine Facilities, at both ends of the LNG chain, constitute a major component of the project and operating costs. Apart from some increases in scale there have been few, if any, technological innovations to bring marine facilities up to date over the past 20 years or more. Marine facilities can benefit from the recent commercialisation of modern cryogenic pipelines and compliant offloading systems with cryogenic flexibles, for both LNG & LPG. These rigid and flexible lines have recently been developed, tested and qualified for a variety of projects and architectures, and can generate significant savings to the overall costs of the marine installations and equipment. The reduction of the installed unit cost of loading lines, through the use of Cryogenic Pipe-in-Pipe technology, allows longer jetties and reduced dredging operations. Costs can be further reduced by installing the Cryogenic Pipe-in-Pipe system along the seabed instead of on trestles. As this is a straight-line system with no expansion loops or bellows, field construction and installation is simplified. A compliant LNG transfer system using flexibles in well-designed support architectures will ensure that offloading can continue with larger excursions of the LNG Carrier, without the need for an extended breakwater for protection. The paper will also address all key and practical aspects relating to the industrialisation and installation requirements for these LNG Marine Terminals and compare cost scenarios between classic and modern solutions. PS6-5.1

2 INTRODUCTION Liquified natural gas was first experimented in the 19th century by Michael Faraday, perhaps better known for the invention of the electric motor through electro-magnetic induction. The first commercial LNG plant was built in Cleveland Ohio, USA in 1941, and the world s first LNG cargo was transported by the Methane Pioneer from Lake Charles, USA to Canvey Island, England in Indeed the first base load plant in Camel, Algeria was constructed by Technip in the early 1960 s. From these humble beginnings we can today count over 50 LNG import regasification terminals, 23 liquefaction plants (most of course with several trains) with a further 7 under completion within the next 3 years, and over 200 LNG Carriers. However this has been a gradual and steady increase in global LNG activity and liquefaction capacity, reaching up to 150 million tons in We are now on the verge of a massive boom in LNG export, import and transport. Currently an extra 140 LNG Carriers are being built or are on order, 47 liquefaction plants are being constructed or extended, whilst a massive 124 new or expanded import terminals are being planned and studied worldwide, even though only a small percentage of these are actually being built today. It is estimated by the International Energy Agency that world liquefaction capacity could reach in excess of 700 million tons by the year 2030, and that the total continuous regasification capacity will be even higher. These new supplies of natural gas can be obtained either from large isolated gas fields or from associated gas from producing oil fields and piped through a gas-gathering network to onshore treatment and liquefaction plants, thus eliminating environmentally damaging flaring. This increase in the number of LNG plants, both for liquefaction and regasification will require extra marine transfer facilities, thus improved facilities linked to reductions in both CAPEX & OPEX will greatly improve the overall efficiency of the LNG business. 1. Location of Marine LNG Terminals 1.1 Overdue Innovation can reduce LNG delivery costs The marine facilities for berthing and mooring of LNG Carriers have so far, been exclusively alongside purpose built jetties, either in protected ports or up-river. This has been required in order to minimise the exposure of rigid loading arms attached to these high freeboard vessels from the effects of wind and waves as these loading arms are only able to cope with minor movements and the slow effects of tidal variations. These same articulated rigid loading arms have had over 40 years to evolve into the complex transfer assemblies that we see today on the LNG jetties and any new systems must integrate all of the operational aspects present in existing systems. It is standard practice in the Oil & Gas business to increase the capacity of existing production fields or facilities. In the LNG world this can quickly create bottleneck problems, as extra facilities will mean extra numbers of Carriers and thus unacceptable PS6-5.2

3 restrictions on other port activities whilst LNG Carrier operations are under way. In a port where waterways and approach channels are often shared with a large variety of commercial and leisure vessels, this creates unacceptable conflicts of the use of facilities. Both safety and security issues also become paramount. Traditional solutions do exist, in the form of dedicated approach channels and/or dedicated LNG ports, in other words the separation of LNG facilities from other marine activities. This however requires both more space and heavy investment. Locating the Marine LNG Terminal, either for export or import, away from the coastline or outside the traditional port, in nearshore conditions is the obvious answer. Any new solutions and architectures being proposed must respect 3 important criteria: Robustness Ease of use Qualification and compliance to existing standards 1.2 Robustness A nearshore Marine Terminal, whether situated 1 km or 5 kms from the coast will have to deal with increased wind and wave effects, both from the longevity and dynamic movement viewpoints and also the availability time for LNG Carrier use, including mooring, LNG transfer and unmooring operations. The largest LNG Carriers have about 10 to 12m draft, thus a typical minimum water depth will need to be in the 12m to 15m range in order to avoid costly and repetitive dredging operations. This range of water depth lends itself to small jackets supporting the LNG transfer system and the mooring/breasting dolphins. An improved overall design, taking into account all operational aspects can ensure maximum availability of the terminal. Design features must allow for: LNG Carrier approach Mooring Transfer system connection LNG transfer operations Transfer system disconnection Unmooring LNG Carrier Departure 1.3 Ease of use The nearshore Marine Terminal must be user friendly. Even if there is less than 2 metres of significant wave height (for example) and acceptable wind levels, an LNG Carrier will have much larger movement than when approaching a sheltered jetty. Welldesigned dolphins, probably with specially engineered fender layouts, must then facilitate mooring operations. Integration of mooring lines with longer tails will also form part of the overall modifications required. Ease of use also means confidence by the LNG Carrier captains and teams in the capability of the Marine Terminal to operate and interact safely in extreme conditions, i.e. in excess of 2m wave heights. PS6-5.3

4 This operational confidence can only be gained by the use of clear and well-defined procedures, based on approved LNG transfer equipment in Certified systems to industryrecognized levels. 1.4 Qualification and compliance to existing standards Whilst a nearshore Marine Terminal may look very similar to standard berthing terminals with mooring & breasting dolphins, the dynamic forces involved are much higher and all aspects must be fully analysed. An ideal method is to start with a thorough Risk Analysis workshop, at which all involved parties should be present and play an active role. A Risk Assessment Plan should be drawn up, with the clear objective of how to achieve Qualification of the Marine Terminal, with special emphasis on all new or novel equipment. Risk Assessments can be carried out at various stages throughout the qualification process, for example, at Concept Design, Detailed Design and Final Evaluation. In addition, and until all procedures are considered to have become routine and fully repeatable, a Risk Assessment prior to each berthing and transfer operation should be undertaken, as well as every time a new LNG Carrier uses the Terminal for the first time. Recognised methodology from any of the major Certification Authorities can be used as a basis and client / local specific requirements linked into the process. 2. Use of modern methods and equipment 2.1 Cryogenic piping The recent industrialisation of large bore, continuous cryogenic piping, both rigid and flexible, lends itself to alternative marine facilities. Until recently the main problem with long length rigid piping has been the requirement for expansion loops and / or bellows integrated into the piping system. By the industrialisation of a robust STRAIGHT LINE pipe-in-pipe, these problems are completely removed and in addition the possibility of subsea installation is opened up Rigid Cryogenic Pipe-in-Pipe (C-PIP) To enable long length Cryogenic Pipe-in-Pipe (C-PIP) to function correctly over a long lifetime, several main criteria have had to be addressed. These are: Qualification of Invar as the inner pipe Qualification of Invar welding material and procedures Use of new Aspen Aerogel insulation material Integrated leak monitoring detection & localisation system Constructability aspects related to bulkheads and inner/outer pipe centralisation Industrialisation & construction methods for long length C-PIP PS6-5.4

5 All of these criteria have been qualified through a Joint Industry Project (JIP) sponsored by a large number of Oil & Gas majors as well as LNG Carrier owner/operators and engineering companies with Technip as the Project Manager. All certification and qualification work has been effected by Bureau Veritas and the American Bureau of Shipping (ref 1). The JIP included the manufacture of a full size test piece (26 ID Invar inner pipe x 32 OD stainless steel outer pipe, 12m long) and a complete test programme. This test programme included insulation performance measurements, such as Overall Heat Transfer Coefficient (OHTC) and evaluation of the mechanical behaviour of the C- PIP under a variety of cryogenic and pressure conditions, to obtain correlation between observed stress/strain values and the Finite Element Analysis (FEA) model predictions. In addition special overmatched welding material and associated procedures were developed by Imphy Alloys (Arcelor Group). To finalise the qualification programme additional mechanical testing was carried out, i.e. burst test, fatigue tests on welded parts, fracture mechanics, corrosion resistance tests. This programme, now complete, has enabled detailed case studies to determine lifetime analysis of the C-PIP in extreme conditions. This has included cyclic evaluation with external temperatures of up to + 80 C (heat sink temperature in the Middle East) and internal temperature of -163 C. In addition the use of Aspen Aerogel provides an excellent inherent fire resistance. This straight-line design of Pipe-in-Pipe facilitates its installation both on trestles or subsea. For trestle/jetty or onshore sections where double containment is required, the outer (Carrier) pipe can be of stainless steel grade 304. For subsea sections the outer pipe will be of carbon steel with a concrete coating for stability and protection purposes. Onsite construction can be from an onshore unit, with the C-PIP being assembled, welded and pulled offshore (subsea or on the trestle), or alternatively a small flat top barge can be used with the C-PIP then being pulled towards the shore line Flexible cryogenic piping & systems The programme to develop, qualify and industrialise long length, heavy duty, large bore cryogenic flexibles through the Amplitude-LNG Loading System (ALLS) JIP at the Gaz de France Montoir-de-Bretagne LNG Import Terminal on the West coast of France, has been widely documented through previous papers. Some of the main criteria addressed have been: Fully insulated flexible (no ice build-up / control of BOG values) All connectivity aspects (Quick Connect Disconnect (QCDC), Emergency Release system (ERS), Guidance system) with the KSB Connectis Constructability of flexibles (dedicated manufacturing facilities) Integrated leak monitoring detection & localisation system Qualification of all mechanical operations (connection, disconnection, emergency disconnection, storage) Verification of the ALLS operational criteria under dynamic operation and with flow of live LNG (pressure drop, temperature gradients, vibration, flow rates etc) PS6-5.5

6 However a major part of the ALLS qualification and certification process has been the definition and writing of all operational procedures. These relate to ALLS installation (on an FSRU or jetty for example), on-site testing, cool-down, connection, LNG transfer, disconnection, emergency disconnection, storage, purge and inerting. All of these procedures, once approved, can be included in the Operational Risk Assessment for all new Marine Terminals as discussed above. In addition to the component Type Approval work carried out by Bureau Veritas - BV (for the Flexi France flexible and the KSB Connectis ), all of this detailed and methodical work is an integral part of the Qualification process being carried out by Det Norske Veritas - DNV, under the RP A-203 Qualification Procedures for New Technology (ref 2). This process includes Technology Assessment, Failure Mode Identification and Risk Ranking (High/Medium/Low), Qualification Methods, Hazid/Hazop and Success Evaluation (Probability of Success - POS). During this process 3 important steps lead to final Certification: Technology Assessment Report, with Statement of Feasibility Certificate (at startup) Technology Qualification Plan, with Statement of Endorsement, and finally Technology Qualification Report, with Certificate of Fitness for Service. Even more important for the LNG Industry is the qualification by DNV of the 3 principal architectures for integration of the ALLS in Marine Terminals. These 3 architectures are: a) Ship-to-shore: ALLS on a jetty b) Ship-to-ship, Side-by-side: ALLS on FSRU or RV c) Ship-to-ship, Tandem offloading: ALLS on stern of FSRU or FPSO It is the combined experience coming from the full-scale trials and the qualification of these architectures, which gives the LNG Industry a solid basis on which to evaluate the feasibility and operability of new Marine Architectures. In the case of marine loading or offloading of LNG at a nearshore Marine Terminal, the terminal can be linked to the onshore process facilities by the C-PIP, either on trestles or installed subsea, thus bringing together all of these new advances. 3. Safety and Security of Marine LNG Terminals Two of the principal concerns in the siting of LNG terminals, especially Import terminals, are those of safety and security. This is applicable to the 2 main components of any LNG site the LNG transfer facility and the process and storage equipment itself. Within the context of this paper it is the siting of the LNG transfer facility that is of immediate interest. PS6-5.6

7 Several recent studies, in both the USA and Europe have stated that remote siting of LNG terminals is a primary factor in security. One such study concludes because of the inevitable uncertainties inherent in large-scale use of new technologies the public can be best protected by placing these facilities away from densely populated areas. (ref 3) One way of achieving this is to move the terminal offshore, either the entire unit including the process facilities, or just the Marine Terminal itself. Although the LNG shipping record has been exemplary in terms of its safety record, the massive increase in LNG trading, as described above and which has already started, will increase the risk of marine incidents close to shore and in traditional terminals. Extra space, extra separation of routes and dedicated LNG approach routes to offshore/nearshore LNG transfer facilities will assist in allaying public anxiety in this respect. 3.1 Design of Marine Terminals A modern Marine LNG Terminal should be designed to meet 3 main requirements: Full operability for a full range of LNG Carrier sizes, = from less than 70,000m³ up to more than 260,000m³ Constant & high number of transfers, 2 per week or more = more than 100 loadings per year Largest possible operability envelope in harsh conditions = maximum up time. These 3 conditions together require a fully flexible LNG transfer system which can operate with minimum maintenance and ensure a long life time before any major change out programme is needed. It is widely accepted that an up time of 95% is required - AS A MINIMUM. Even this means about 18 to 20 days per year of down time due to adverse weather-sea conditions. Whilst this may appear compatible with 100 loadings per year, it is impossible to predict how these days of non-operability would be spread out over a 12- month period. A well-designed Marine Terminal can increase this figure of 95% by two or three points by the use of new technologies. Such a terminal should incorporate a specifically designed ALLS (as described above) with the appropriate architecture for each site, linked to a modern approach to mooring & breasting dolphins, mooring lines and fenders. By the use of the straight line C-PIP, separation from the coast and thus improved public perception, is accomplished Flex-Quay An LNG transfer system can only be as good as its surrounding support architecture. In the case of Marine Terminals on extended length jetties, the Technip Flex-Quay has been specifically designed. This gives several advantages, all with the aim of achieving the utilisation figure of over 97%, these being: Adaptable to the weather-sea conditions for each site Integration of ALLS with custom built lengths of flexible transfer lines Presentation of mobile connection ends to the LNG Carrier midships manifolds PS6-5.7

8 Use of Qualified and Certified systems and procedures for dynamic service In addition the Flex-Quay and ALLS together presents a significant weight optimisation when compared to rigid arm alternatives in the region of 1/5 th overall weight. This leads to reduced platform & jacket size and construction costs. Any required maintenance can easily be achieved by a workboat with an adequate deck crane, thus avoiding the need for heavy lift capacity barges. The Emergency Shut Down limits ESD 1 and ESD 2 as defined in EN1474 (ref 4), are integrated into the overall Flex-Quay/ALLS design and the length of the flexibles are specifically designed for each site. For example if an ideal minimum length for the flexible transfer lines is calculated to be 40m, then an extra 3 or 4 metres would give a larger comfort zone even after reaching ESD limits for emergency disconnection. In an exposed jetty, should an LNG Carrier start drifting away, then the effect of wind on the high freeboard can quickly lead to a speed of several metres per second, so an extra length in the design of the flexibles is an obvious plus. With further reference to the Operating Envelope and the flexible loading system, two main criteria will define the Marine Terminal up time (or time for LNG loading or offloading operations): Tanker moored 1 st and 2 nd order motions due to environmental conditions (waves, winds, surface currents) Tanker variable draft during loading/offloading operations The above will define the envelope of the connection point (cryogenic flexible - tanker manifold) and the minimum operating requirement for the flexible loading system. The following (typical) operating envelope is an example of the large amplitude of movements that can be accepted: In horizontal axis: from 0 up to 5m due to tanker sway as well as from -0.5 m to 0 due to fenders compression (tanker motions) In transversal axis: from -5 m to +5 m due to tanker surge In vertical axis: from -7.5 m to +7.5 m approximately due to tide, and tanker loading draft Again, larger Operating Envelopes could be accommodated by means of longer cryogenic flexible. Transfer of associated LPG will also benefit from the same technological advances Mooring lines There is little benefit to be gained from the use of a Flex-Quay system incorporating the ALLS if utilisation limits are still determined by mooring or fender systems which themselves have not been optimised, bearing in mind the three main requirements shown in 3.1 above. A recent study by Tension Technology International, as part of the Effective Moorings JIP (ref 5), concluded that increased excursions of both 138,000m³ and 267,000m³ LNG Carrier in higher wave heights can be accepted when increased mooring line tail lengths of 22m (instead of 11m) are used. PS6-5.8

9 Whilst the more standard 11m-tail length gives adequate fatigue life in up to 1m significant wave height and 35-knot winds, this quickly becomes unacceptable with wave heights up to 2m sig. where the fatigue life falls below 12 months. To meet on-berth conditions of 2m-sig-wave height and up to 60-knot wind speed this increased tail length and probably a larger number of mooring lines is required. This may mean refitting some older Carriers with new and/or an increased number of winches. Increasing the mooring system compliance will lead to increased LNG Carrier motions which in turn are then taken care of by the Flex-Quay/ALLS combination. Doubling the tail-line length can lead to acceptation of double the wave height, whilst multiplying their fatigue life by a factor of Fenders Another vital component to consider in Marine Terminals is the implication of increased dynamic movements on the fenders. For such large facilities and LNG Carrier only the largest fenders will ensure that they do not become the limiting factor in the operational uptime that is needed. Fender size of 4.5 metres in diameter, and a length of 9.0 metres will generally be used. These heavy-duty pneumatic rubber fenders are typically supplied from Yokohama Fenders (ref 6). Full studies on compression speed, reaction forces and energy absorption will be required as an integral part of the modern Marine Terminal qualification package. The calculation tables for fenders, developed for large LNG Carrier energy absorption in rough conditions will also determine the number of fenders and their exact placement locations. 4. Cost Considerations When comparing the cost of a nearshore LNG Marine Terminal, linked to the onshore facilities by the C-PIP, to a more classic solution in today s terms, it is the overall scenario that has to be studied. The cost difference of the terminal (platforms, transfer system, mooring & breasting dolphins, fenders) is minimal and of no consequence when included in the overall pricing estimations linked to the functioning of the complete LNG chain. Whilst it will be more expensive to install the required stand-alone tripods or jackets further from the coast and in 15m-water depth, these are simple operations for the Oil & Gas Industry. Against this is the cost reduction achieved by using the straight-line C-PIP, which significantly reduces the trestle / jetty costs for both procurement & installation, by the elimination of expansion loops. The Flex-Quay itself, due to its lightweight, will generate price savings on an installed basis together with its support jacket. Further more the potential of CAPEX savings by the elimination or reduction in size of any breakwater, and reduced OPEX by the elimination or reduction in repetitive dredging operations, will also have an impact on the overall cost of the LNG facility. However the main financial benefits will come from the increased availability of the Marine Terminal for LNG Carrier operations. If a Marine Terminal that incorporates all of the improvements as described in this paper can ensure an availability of 97% or 98%, then it is probable that a gain of 3 or 4 LNG Carrier cargoes can be secured over every 12-month period. Even using a price of 6 USD per mmbtu, the value of an LNG Carrier PS6-5.9

10 cargo of 135,000m³ size is about 18 million USD. For example by increasing the number of cargoes from 100 to 104 then an extra 72 million USD per annum is added to the financial turnover of each LNG terminal. CONCLUSIONS The whole philosophy of increased worldwide LNG trading, with Carriers available to load or unload cargoes at a large variety of terminals will depend in part on modern Marine Terminals equipped not only to moor and unmoor LNG Carrier of varying sizes, but more essentially to enable the uninterrupted transfer of LNG. By ensuring that the ESD limits are compatible with increased wave heights and wind speeds, the overall operability and monetization of the LNG chain is assured. Whilst we envisage that acceptable limits of 4m-sig-wave height can be attained by use of integrated Marine Terminals as set out in this paper, these limits are today unacceptable due to other criteria, namely handling tug and LNG sloshing constraints. However maximum Marine Terminal availability with increased dynamic conditions in wave heights of 2 to 3 metres are now easily achievable without any significant increase in safety concerns. These new Marine Terminals can be designed and installed on a Turnkey basis by the Technip Group, further enhancing the integrated engineering approach required by the LNG Industry. By moving the Marine Terminal further offshore, the security aspect is also addressed thus raising the acceptability level by the general public, facilitating the award of the inevitable permits and reducing the related costs. As always in the Oil & Gas sector, an integrated approach to new methods & equipment is needed, and Marine LNG Terminals are no exception. Thorough evaluation from Risk Analysis stage through to operability and interface with the LNG Carrier s will ensure that the excellent safety record in the LNG business is maintained. The combination of commercially available innovations including C-PIP, flexible cryogenic hose and dynamic loading quays will allow the long overdue lowering of costs for the marine terminals of LNG projects while at the same time allowing improved safety and high availability. REFERENCES CITED Ref 1: ABS Review and Approval of Novel Concepts: June 2003 Ref 2: DNV RP A-203: Qualification Procedures for New Technology Ref 3: CRS Report for Congress LNG Import Terminals: Siting, Safety & Regulation Ref 4: EN 1474 (new version) Design and Testing of Marine Transfer Systems, Pt 2: Design and Testing of Transfer Hoses Ref 5: Tension Technology International JIP: Develop effective Moorings for Tanker & Gas Carrier Terminals Exposed to Waves Ref 6: Yokohama Floating Fenders Pneumatic 50 & 80 PS6-5.10

11 ACKNOWLEDGEMENTS Technip acknowledges the support of the Participants and partners of the JIPs and work described in this paper, however the opinions expressed are entirely those of Technip: ABS, Aspen Aerogels, BP, B.V., Chevron, ConocoPhillips, DNV, Eurodim, ExxonMobil, Fendercare, Gaz de France, Hoegh LNG, Imphy Alloys, KSB, Petrobras, Shell, Statoil, Total PS6-5.11