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INDUSTRIAL SERVICES | LNG
Mid-scale LNG does not require multiple trillion cubic feet (tcf) gas finds. A 1.5 mtpa mid-scale LNG project only requires recoverable reserves of 1.7 tcf over a 20-year life compared to 4-5 tcf for a conventional 3.6-4.5 mtpa LNG plant. This makes finding gas reserves for a mid-scale project less difficult as 4-5% of world gas fields are greater than 1 tcf compared to 1% that are greater than 5 tcf.
Mid-scale LNG is being proposed for locations in Southeast Asia (e.g. Sengkang) and West Africa (e.g., Gasol in the Republic of Congo and Gabon, GdFSuez in Cameroon) where smaller gas fields have not been developed to date.
LNG plant considerably, the storage tank is the longest- schedule item. To minimize costs, a single-tank solution is preferred, but a conventional, large LNG tank will reverse the schedule gains from liquefaction. To date, the embry- onic mid-scale LNG industry has not developed a common strategy to address this issue.
Regions of Implementation
A clear advantage of mid-scale LNG over conventional baseload LNG projects is the fact that it does not require multiple trillion cubic feet (tcf) gas finds. This makes find- ing suitable gas reserves less difficult. Many of the locations that mid-scale LNG is being proposed for are in South East Asia and West Africa, where smaller gas fields have not been developed as economies of scale have prevented commer- cialization. Specialized markets also exist in Norway and China where environmental concerns and the supply-de- mand deficit are driving development (see map).
Potentially the largest market for mid-scale LNG is, how- ever, offshore. Efforts to develop a floating LNG (FLNG) liq- uefaction project are progressing rapidly. There are two de-
STUDY. LNG FPSO concept design.
TERMINAL. Discharging a shipment from an LNG tanker.
sign concepts: While the oil supermajors are attempting to marinize the baseload LNG technologies to produce large- tonnage FPSOs, entrepreneurs are looking at smaller ca- pacities using mid-scale LNG technologies.
Floating LNG offers the potential to considerably reduce costs within the LNG industry. Furthermore, loading off- shore solves many environmental, political and access-re- lated issues, provided it can be technically demonstrated on a consistent basis.
Firstly, the physical plant size must be smaller, as the deck area is limited. As a result, safety concerns must be given special attention. Secondly, equipment sizes may need to be reduced to minimize the impacts of wave mo- tion on performance. And finally, maintenance is more dif- ficult, requiring more attention to availability and equip- ment selection. The resulting need to minimize equipment, hazardous inventories and manning levels makes the ni- trogen-based liquefaction processes of the peak-shaving industry a natural choice for FPSOs. The absence of a hy- drocarbon-based refrigerant significantly lowers the risk of fire or explosion and minimizes the environmental impact. The first offshore nitrogen-type refrigeration units for LNG are already in service on LNG ships, and no problems have been reported over the first months of operation. Several nitrogen-cycle floating liquefaction vessels are on order. Other, smaller offshore liquefaction developers have opt- ed for alternative strategies.
While the credit crunch and potential worldwide reces- sion have taken the edge off international LNG prices, price levels remain sufficient for mid-scale LNG to profitably en- ter the market. In particular, offshore mid-scale LNG seems
to be here to stay.
For further information: David Haynes, Principal LNG Consultant, Phone: +44 1509 282829, E-Mail: email@example.com