Simultaneous environmental and economic process synthesis of isobutane alkylation

• Published in: Journal of cleaner production 2014-10, Vol.81, p.270-280
• Main Authors: García, Norberto, Fernández-Torres, María J., Caballero, José A.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Applied sciences; Biological and medical sciences; Conservation, protection and management of environment and wildlife; Ecoindicator-99; Environment and sustainable development; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Generalized Disjunctive Programming; Global Warming Potential; Isobutane alkylation; Life Cycle Assessment; Multiobjective optimization; Pollution
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2014.06.016

This multidisciplinary study concerns the optimal design of processes with a view to both maximizing profit and minimizing environmental impacts. This can be achieved by a combination of traditional chemical process design methods, measurements of environmental impacts and advanced mathematical optimization techniques. More to the point, this paper presents a hybrid simulation-multiobjective optimization approach that at once optimizes the production cost and minimizes the associated environmental impacts of isobutane alkylation. This approach has also made it possible to obtain the flowsheet configurations and process variables that are needed to manufacture isooctane in a way that satisfies the above-stated double aim. The problem is formulated as a Generalized Disjunctive Programming problem and solved using state-of-the-art logic-based algorithms. It is shown, starting from existing alternatives for the process, that it is possible to systematically generate a superstructure that includes alternatives not previously considered. The optimal solution, in the form a Pareto curve, includes different structural alternatives from which the most suitable design can be selected. To evaluate the environmental impact, Life Cycle Assessment based on two different indicators is employed: Ecoindicator 99 and Global Warming Potential. •A disjunctive model is used for the isobutane alkylation process.•Simultaneous economic and environmental objectives are considered.•New alternatives never studied before of the alkylation process are considered.•A hybrid simulation-multiobjective optimization approach is used.•Rigorous design is used instead of shortcuts or approximate models.