DIAZ Maria Soledad
Dynamic Modelling And Optimisation Of Cryogenic Systems
MARIELA RODRIGUEZ,; MARIA SOLEDAD DIAZ
APPLIED THERMAL ENGINEERING
Lugar: Amsterdam; Año: 2007 vol. 27 p. 1182 - 1190
This work addresses the dynamic optimisation of the cryogenic sector in a large-scale natural gas processing plant. Main attention is focused on rigorous dynamic modelling of countercurrent heat exchangers with phase change and a subsequent high-pressure separation tank. The original distributed parameter problem, which results from dynamic energy balances in countercurrent heat exchangers, is transformed into an ordinary differential system (ODE)by performing spatial discretisation with the method of lines. The entire model comprises algebraic equations for thermodynamic predictions with the SoaveRedlichKwong (SRK) equation of state, hydraulic and design equations. The differential-algebraic equation(DAE)optimisation problem is solved with an advanced simultaneous strategy that transforms the original problem into a large-scale nonlinear programming (NLP)problem through discretisation in time of the entir eset of variables by collocation on ﬁnite elements. Model resolution provides optimal temporal and spatial proﬁles for pressure and temperature in heat exchangers, together with partial condensation description.