This paper describes a new way of designing LNG liquefaction plants using a tool only recently available. An LNG plant is typically designed based on two or three material balances corresponding to different feed compositions and ambient conditions. Each material balance is performed as a design case i.e. the same approach temperature in exchangers, constant pressure anchor points, etc. Then equipment is sized for the controlling case of each material balance. The resultant eclectic design does not correspond to any specific case and actual production is normally higher than expected. Using a recently developed dynamic simulation program, in a steady state mode, can now largely eliminate this inherent over-design. The program is an invaluable tool for debottlenecking studies/design and optimization. This Paper Presents typical examples of the different options available with this new program, namely: Design case (fixed temperature approaches, pressure profile, compressor/pump curves, etc.) and rating cases (fixed exchanger area and line sizes, same compressor/pump curves, etc.); Determination of maximum production (given an objective economic function) by optimizing mixed refrigerant composition, compressors pressure ratios, etc. Accurate and fast debottlenecking design. The program indicates for the new conditions the production limiting section of the plant. Contribution that a plant operator should make to a debottlenecking study in order to provide a contractor with a reliable database.
展开▼
