چكيده به لاتين
Low temperature gas separation processes have a high Total Annual Cost, TAC. Because performing of low temperatures is more expensive. The olefin plants cold end which consists of a train of distillation columns is one of these processes. The economic aspects of olefin plants are of much interest and importance as they provide many downstream petrochemical plants feeds, thus any possible improvement in their costs indirectly affect other affiliated downstream industries costs, significantly. There are significant improvement potentials to reduce the costs of the olefin plants cold end. Study about various possible distillation columns sequences of this plant as one of the mentioned potentials, could be an important.
Industrial separations are usually multicomponent and synthesis of distillation columns sequences problems with more than two components separations are made complex due to the various possible options, thus using software to do these works more automated could be a beneficial. In this thesis, simple and complex sequences of the cold end of an olefin plant are studied. So, separation matrix, SM, algorithm is used to generate various configurations. Shortcut method is used to determine columns operating pressures and as an initial guess of other parameters for rigorous method in Aspen Plus environment. Genetic algorithm is then used to optimize sequences. All sequences are then compared against each other under their optimum conditions considering sequences costs and exergy losses. All these steps are performed respectively and automatically using the Matlab environment and connection capability of this software to Aspen Plus is used in simulation stage. Five case studies of various feed streams of olefin plants cold end are checked using this approach. The first one confirmed the confidences of the approach for the later studies. The results of four case studies showed that the simple sequences are better than the complex ones. But in the fifth case study due to different feed stream specifications, a complex configuration was selected as the one with the best economic performance according to TAC with a performance 8.51% better than the first simple sequence.
Keywords: Process synthesis, Distillation columns sequences, Olefin plant cold end, Genetic algorithm
