Performance design of a cryogenic air separation unit for variable working conditions using the lumped parameter model

摘要: Large-scale cryogenic air separation units (ASUs), which are widely used in global petrochemical and semiconductor industries, being developed with high operating elasticity under variable working conditions. Different from discrete processes traditional machinery manufacturing, the ASU process is continuous involves compression, adsorption, cooling, condensation, liquefaction, evaporation, distillation of multiple streams. This feature indicates that thousands technical parameters heat transfer, correlated merged into a large-scale complex system. A lumped parameter model (LPM) proposed by lumping main factors together simplifying secondary ones to achieve accurate fast performance design. On basis material energy conservation laws, piecewise-lumped extracted conditions using LPM. Takagi-Sugeno (T-S) fuzzy interval detection recursively utilized determine whether critical point detected or not different thresholds. Compared method, LPM particularly suitable for “rough first then precise” modeling expanding feasible domain intervals. With LPM, compressor, molecular sieve adsorber, turbo expander, plate-fin exchangers, packing column 100000 Nm3 O2/h enhanced adapt The designed value net power consumption per unit oxygen production (kW/(Nm3 O2)) reduced 6.45%.