Juan Gabriel Segovia-Hernández

The chemical industry comprises of the companies that produce industrial chemicals. It is central to the modern world economy, converting raw materials into more than 70 000 different products. However, environmental regulations and the risk of climate change are putting pressure on the chemical industry to minimize greenhouse gas emissions. In this work, we use the concept of process intensification (using thermally coupled distillation) to reduce energy consumption and CO₂ emissions in a plant for the separation of amines. The results show that the use of thermally coupled distillation sequences can be related to a reduction in energy consumption, greenhouse gas emissions, and good theoretical control properties in the re‐designed plant.

The optimal design of dividing wall columns is a non‐linear and multivariable problem, and the objective function used as optimization criterion is generally non‐convex with several local optimums. Considering this fact, in this paper, we studied the design of dividing wall columns using as a design tool, a multi‐objective genetic algorithm with restrictions, written in Matlab^TM and using the process simulator Aspen Plus^TM for the evaluation of the objective function. Numerical performance of this method has been tested in the design of columns with one or two dividing walls and with several mixtures to test the effect of the relative volatilities of the feed mixtures on energy consumption, second law efficiency, total annual cost, and theoretical control properties. In general, the numerical performance shows that this method appears to be robust and suitable for the design of sequences with dividing walls.

A Petlyuk distillation column, considering equilibrium and non‐equilibrium stage models, was studied. Rigorous simulations were conducted using Aspen Plus™ RATEFRAC Module for the separation of ternary mixtures. According to the equilibrium model, the energy‐efficient design of the Petlyuk column requires that the intermediate component be extracted from the maximum point in the composition profile in the main column. It was found that, for the intermediate component, mass transfer occurs from the vapour to the liquid phase from the top of the column to the stage where the side stream is extracted, from this point mass transfer occurs in the opposite direction. This point, considering the non‐equilibrium model, corresponds to the stage in which the net mass transfer rate is zero. For the case of two segments per stage, it was found that the heat duties predicted by the equilibrium model are significantly lower than those obtained by using the non‐equilibrium model, which is consistent with previous reported results. However, it is important to say that despite the higher energy duty predicted by the non‐equilibrium model; both models predict significant energy savings.