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TPG-4140LNG, fundamentale prinsippBengt Olav Neeraas18/09/2007

Large Capacity LNG Plant Development J.J.B. Pek*, A. van Driel, E.C.J.N. de Jong, R. Klein Nagelvoort

LNG technology selectionDr Tariq Shukri, Foster Wheeler, UK, discusses availableLNG technologies and the important criteria for selection.

This process, a modified version of a process used in an earlierplant in Alaska during the 1960s, was used for the AtlanticLNG plant in Trinidad and for a baseload plant under constructionin Egypt. Train capacities of up to 3.3 million tpy havebeen constructed with larger trains in development. Thisprocess is illustrated in Figure 4.Refrigeration and liquefaction of the process gas isachieved in a cascade process using three pure componentrefrigerants; propane, ethylene and methane, each at two orthree pressure levels.This is carried out in a series of brazed aluminium PFHEsarranged in vertical cold boxes. Precooling could be carriedout in a core-in-kettle type exchanger.The refrigerants are circulated using centrifugal compressors.Each refrigerant has parallel compression trains.Frame 5 gas turbine drivers were used.

http://www.worldoil.com/Magazine/MAGAZINE_DETAIL.asp?ART_ID=2808&MONTH_YEAR=Feb-2006Global LNG Report Process selection is critical to onshore LNG economics Despite evolving and diversifying, no one liquefaction process is substantially better than others, mandating that project-specific variables and economics be studied. Saeid Mokhatab, University of Wyoming, Laramie, Wyoming, and Michael J. Economides, University of Houston, Houston February 2006

Phillips Petroleum Company developed the original Optimized Cascade There are advantages and disadvantages to POCLP. 7 Advantages LNG Process (OCLP) in the 1960s. The objective was to develop a include low installation costs, as reported for the Atlantic LNG project liquefaction technology that permitted easy start-up and smooth in Trinidad, plus a two - train - in - one reliability concept, using one operation for a wide range of feed gas conditions. train of liquefaction exchanges served by two parallel compressors This process was first used in on each refrigerant. 1969 at Phillips Petroleum's Kenai, Alaska, LNG facility. The facility was constructed by Bechtel and was the first to ship LNG to Japan. Disadvantages include many gas turbines and compressors, thus It is the world's first LNG project to achieve 34 years of uninterrupted the maintenance requirement can be high. In addition, there are limited supply to its Japanese customers. Fig. 4 provides an overall schematic train capacities. The largest POCLP train in operation is 3.0 MTPA, of a typical POCLP while the largest in construction is 3.3 MTPA. Furthermore, the process

requires ethylene import for refrigerant make-up. Exclusivity in the This process uses two pure refrigerants - propane and ethylene circuits, Phillips/ Bechtel alliance limits competition in the EPC phase. and a methane flash circuit - cascaded to provide maximum LNG production by utilizing the horsepower available from 6 Frame 5D gas turbines. The POCLP can provide designs with high thermal efficiency and Each circuit uses two 50% compressors with common process equipment. achieve designs optimized for project economics. The process utilizes

proven technology and equipment, and has a wide range of operational The compressor and turbine packages are manufactured by Nuovo flexibility. Turndown rates to 10% are achievable for long-term operation. Pignone of Florence, Italy. Brazed aluminum heat exchangers and Due to the pure component systems, the plant has easy start-up and operation. core-in-kettle exchangers are used for the feed gas, propane, The plant boasts low utility and reduced flaring requirements, because ethylene and methane circuits. All of these heat exchangers, refrigerants are not flared on typical upset conditions. with the exception of the This leads to reduced requirements for maintenance and operational staffing. 8 propane chillers, are housed in two "cold boxes." All compressor inter-cooling, after-cooling and propane refrigerant condensing is 7 Mlnvik, M.J., "LNG technologies-State of the art," Statoil, NTNU provided by fin-fan heat exchangers. The LNG from the last-stage Global Watch Seminar: Gas Technology, Norway, Aug. 29, 2003.flash drum is sent to the LNG tanks by the LNG transfer pumps, 8 Houser, C. G., J. Yao, D. L. Andress and W. R. Low, "Efficiency where it is stored at about 70 mbar and - 161C. improvement of open-cycle cascaded refrigeration process,"

US Patent 5,669,234, Sept.23, 1997.

http://www.worldoil.com/magazine/MAGAZINE_DETAIL.asp?ART_ID=3165&MONTH_YEAR=Apr-2007Breaking the offshore LNG stalemate Most technical obstacles to offshore liquefaction have already been overcome. Growing LNG demand may push industry and governments to conquer the remaining hurdles. Saeid Mokhatab , Contributing Editor, LNG, World Oil; and David Wood , David Wood & Associates, Lincoln, UK April 2007

Optimized cascade . In this cycle, natural gas is cooled, condensed The cascade cycle's main disadvantage is the high capital cost due and sub-cooled in heat exchange with propane, ethylene (or ethane) to each refrigeration circuit's need for its own compressorwith and finally methane in three discrete stages. Each refrigerant circuit associated suction drums and interstage coolersand refrigerant storage. normally has three or four refrigerant expansion-compression stages. The large number of equipment items and the large plot space mean After compression, propane is condensed with cooling water or air, that this cycle is neither technically nor economically viable for offshore applications. ethylene is condensed with evaporating propane, and methane is condensed with evaporating ethylene. Phillips' optimized cascade process (Fig. 2) is a modified and updated version of the simple process used in a pioneering Alaskan plant built in the 1960s. It has been used for the Atlantic LNG plant in Trinidad and for recently completed baseload plants in Egypt and Darwin, Australia, and is being applied in a plant under development in Equatorial Guinea. Train capacities up to 3.6 million t/yr have been constructed.

Fig. 2. Optimized cascade refrigeration processes have the advantage of thermodynamic efficiency, but the disadvantage offshore of large plot plan and multiple refrigerant handling.

The cascade cycle requires less power than any other liquefaction cycle, mainly because the refrigerant flow is lower. It is also flexible in operation as each refrigerant circuit can be controlled separately. Specific power is low, but the plant is complex. Each refrigerant requires its own storage, which would need to be imported or a separate support vessel.

NGV2004 Small Scale LNG Production Technologies. Use in heavy Transport. Author: Lic. Eduardo Barreiro. SMALL LNG PRODUCTION TECHNOLOGIES Coolant cascade (for big scale plants)

A series of compression /expansion cycles are connected, having each cycle its own compressor.

Coolants with low boiling point are used in the cycles of lower temperatures. The cycle of lower temperature eliminates the remaining heat of the cycle that is at a higher temperature Finally cycle of higher temperature eliminates heat to the ambient.

This process has the best thermal efficiency, but simultaneously requires a great investment. This is the cycle which used by huge units, the investments are in the order of several hundred million dollars, and cannot be applied for the argentine reserves and market.

The plants of liquefaction of this technology have huge cost. This problem is not only Argentine, but worldwide. So several countries have invested in developing new technologies with small cost, than already they are available for the market. This are dedicated technologies: designed for the specific case. They are based on the Joule Thomson principle.

COMMERCIAL AND TECHNICAL CONSIDERATIONS IN THE DEVELOPMENTS OF OFFSHORE LIQUEFACTION PLANT COMMERCIAL AND TECHNICAL CONSIDERATIONS IN THE DEVELOPMENTS OF OFFSHORE LIQUEFACTION PLANT23rd World Gas Conference, Amsterdam 2006.Chen-Hwa ChiuSenior Technology AdvisorChevron Energy Technology Company1500 Louisiana StreetHouston, TX 77002

DRIVER SELECTION FORLNG COMPRESSORSDr Sib AkhtarMSE (Consultants) LtdCarshalton, Surrey SM5 2HWsib.akhtar@mse.co.ukhttp://www.mse.co.uk Tel: 020 8773 450014th December 2004

Simple to design and operate

Simple cycle Frame 5 gas turbines mechanical drive

No helper turbine or large motor needed for start-up

Increased size with two gas turbine trains for eachrefrigerant process

Parallel compressor trains avoids capacity limits

Increased CAPEX due to more (six) trains offset byincreased availability 95-96% with parallel train operation

Loss of one train does not cause plant shut down

Production carries on with reduced capacity

Refrigerant and exchangers temperature not affected byone train trip enabling quick restart

ALNG Trinidad

Propane pre-coolingCentrifugal compressors2 x Frame 5 C upgraded to D

Ethylene and Methane cyclesCentrifugal compressors2 x Frame 5 C upgraded to D for each cycle

Plant Capacity 3 MTPA Raised to 3.3 MTPAHigh Availability 95-96%

NATURAL GAS LIQUEFACTION PROCESSES COMPARISONCOMPARAISON ENTRE PROCEDES DE LIQUEFACTIONDE GAZ NATURELPierre-Yves MartinJrme PigourierAxens (France)www.axens.frBatrice FischerIFP (France)Poster PO-39PO-3 9.1

Trinidad plant is built with a cascade process (propane/ethylene/methane), with also several levels of pressure on each cycle . The process (see figure 2) is arranged so as to have the same power on the three cycles. Another interesting feature is to install parallel lines of compression, with Frame 5 - variable speed gas turbine - so as to have a high availability and easier operation: no compressor trip will shut down completely the unit, and the restart of the compressor can be done without loss of refrigerant.