A Nonlinear Programming Approach to Conceptual Design of Reaction-Separation Systems

Conceptual chemical process design in a sustainable technological world

Systematic design methods are widely diffused in academia, representing a standard in many engineering courses. Nevertheless, some flaws related to the conceptual design phase have been ascribed to these methods, especially concerning a non-comprehensive support to innovation. However, literature acknowledges several creativity-enhancing tools that can be conveniently combined with systematic design methods. In particular, many scholars refer to TRIZ, i.e. the well-known Russian problem-solving theory. Moreover, recent literature contributions propose some alternatives to the classical Functional Decomposition and Morphology (FDM), claiming to overcome some of the related flaws. One of them is the Problem Solution Network (PSN) approach, i.e. a systematic conceptual design method strongly based on a problem-solution co-evolutionary logic. In this context, our work aims at combining the potentialities of TRIZ with the benefits claimed for the PSN, by proposing a comprehensive integration procedure. Accordingly, this paper reports a detailed description of the proposal, where TRIZ tools are exploited to support problem solving within the PSN approach. Furthermore, an application is also reported where an industrial case study is presented to argue about possible potentialities and lacks of the proposed approach.

Although many information systems (IS) design methods and techniques are available to IS professionals, none of them completely supports the design process. One of the problems is that there is a mismatch between IS design method; and the system to be built. Actually, in designing an IS, the methods or techniques employed should match the types and characteristics of the system to be built. Thus paper will explore the relationship between IS types/characteristics and systems design methods, and provide IS designers with a systems framework to develop methods or techniques that match the types and characteristics of IS.

The objective of this research project is the development of a second generation in-duct sorbent injection technology as a cost-effective compliance option for the 1990 Clean Air Act Amendments. Research focused on the Advanced Coolside Process, which has shown the potential of exceeding the performance targets of 90% SO{sub 2} removal and 60% sorbent utilization. In Task 5, Conceptual Process Design and Economic Evaluation, the economics of the CONSOL Advanced Coolside Process as a Clean Air Act compliance option were evaluated. A conceptual process design for full-scale, coal-fired applications is described. Advanced Coolside is compared to conventional Limestone Forced Oxidation (LSFO) wet FGD technology. The process economics for coal sulfur levels ranging from 1.0% to 3.5% (as-received) and plant sizes ranging from 160 to 512 gross MW were investigated, In addition, the economics of on-site versus off-site lime hydration and the cost sensitivity to delivered pebble lime and hydrate prices are investigated, Advanced in-duct sorbent injection enjoys a capital and levelized cost advantage relative to LSFO in all cases examined in this study. As a result of this study and others made during this contract, the following conclusions can be made: (1) The capital cost of Advanced Coolside is 55% to 60% less than that of LSFO and varies slightly depending on coal sulfur content and plant size. (2) The total levelized SO{sub 2} control cost advantage relative to LSFO varies from 15% to 35% over the range of coal sulfur contents and plant sizes evaluated. This cost advantage is sensitive to sorbent transportation charges. As a result, the economics are site-specific. (3) The experimental optimizations based on interim economic analyses were the key to capital and levelized cost reductions.

A framework for the integration of solvent and process design with controllability assessment

PurposeTo investigate the feasibility of using artificial neural networks for conceptual design of bracings systems for tall steel buildings.Design/methodology/approachDatabase of 234 design examples has been developed using commercially available detailed design software. These examples represent building up to 20 storeys. Feed forward back‐propagation neural network is trained on these examples. The results obtained from the artificial neural network are evaluated by re‐substitution, hold‐out and ten‐fold cross‐validation techniques.FindingsResults indicate that artificial neural network would give a performance of 97.91 percent (ten‐fold cross‐validation). The performance of this system is benchmarked by developing a binary logistic regression model from the same data. Performance of the two models has been compared using McNemar's test and receiver operation characteristics curves. Artificial neural network shows a better performance. The difference is found to be statically significant.Research limitations/implicationsThe developed model is applicable only to steel building up to 20 storeys. The feasibility of using artificial neural networks for conceptual design of bracings systems for tall steel buildings more than 20 storeys has not been investigated.Practical implicationsImplementation of the broad methodology outlined for the use of neural networks can be accomplished by conducting short training courses. This will provide personnel with flexibility in addressing buildings‐specifics bracing conditions and limitations.Originality/valueIn tall building design a lot of progress has been made in the development of software tools for numerical intensive tasks of analysis, design and optimization, however, professional software tools are not available to help the designer to choose an optimum building configuration at the conceptual design stage. The presented research provides a methodology to investigate the feasibility of using artificial neural networks for conceptual design of bracings systems for tall buildings. It is found that this approach for the selection of bracings in tall buildings is a better and cost effective option compared with database generated on the basis of expert opinion. It also correctly classifies and recommends the type of trussed bracing system.

Design cognition research aims to investigate the cognitive mechanisms and thought processes of human designers. In previous research, the cognitive activity of experienced and inexperienced designers has been compared in order to identify design strategies leading to design creativity. However, it is still unknown whether the design strategies applied are effective and whether the design processes are efficiently improved. In this paper, cognitive efficiency, describing how designers optimize mental resources to achieve creativity in conceptual design processes, was directly measured by the mental effort of designers and the creativity level of design outcomes. The results showed that the experienced designers generated more design concepts with higher quality and variety than did the inexperienced designers. The cognitive efficiency measures indicated that design expertise contributed to improving cognitive efficiency scores of quality. In addition, the systematic design method used by some designers was found to be related to high cognitive efficiency. It can be seen that the evaluation of cognitive efficiency has practical applications for designer training, design methodology evaluation, and design process improvement.

This article presents the mechanism combination's modes, fundamentals, reasoning rules, and realization methods in the automated conceptual design of mechanism systems. According to the combination form between two function units, with the aid of morphology matrix, applying a recursive mode of mechanism combination and the reasoning system based on set theory, the function units' solutions in the form of combination mechanisms can conveniently be generated. The theory and method presented in this article can simplify the process of mechanism combination and the reasoning rules and are suitable for the combination between not only single-degree-of-freedom mechanisms, but also many-degree-of-freedom mechanisms. They have successfully been applied to the software development of automated conceptual design of mechanism systems.

This paper proposes a conceptual design tool, based upon inferential design theory. It has been specifically developed for the design of production and operations systems, but its use can be extended to other engineering areas, such as mechanical and structural systems. Inferential design theory and its foundation in the inferential theory of learning are briefly outlined. Both theories are based on the idea of using specialised knowledge operators in learning and design, termed knowledge transmutations and design knowledge transmutations respectively. The 24 transmutations existing in the two theories are outlined, and a further 12 design-specific transmutations are proposed. These have been developed as a result of our research. A conceptual design process is proposed, in which design knowledge transmutations are used. A software tool for design, CREDO, is also described and an example of its use in the generation of design concepts for an after-sales service facility is presented. The conclusions discuss the initial methodological experience of using CREDO to generate design concepts. They are based on the introductory use of CREDO at Technion in Israel for teaching purposes. Directions for further research are also provided.

Computer tool supported process design methodology

The Structured Systems Analysis and Design Method (SSADM) is the standard method for systems analysis and design in Government batch and transaction processing projects. In SSADM, analysis and design are clearly separated activities. Systems analysis is concerned with defining what has to be done, systems design with how it will be done.

In industrial practice, conceptual process design is typically conducted by repetitive simulation studies, which require detailed design specifications in an early design phase. Guided by heuristics, these iterative solution procedures result in high manual effort and, in addition, no guarantee concerning the quality of the solution can be given. Optimization-based design methods provide a tremendous potential to accelerate and improve conceptual process design. For this purpose, a synthesis framework for the optimization-based design of chemical processes is presented in this thesis. Powerful shortcut and rigorous evaluation methods for reaction and distillation are presented. These methods are computationally efficient in order to allow an optimization-based design of large-scale chemical processes. Various industrial case studies illustrate the application of the novel approaches and highlight their benefits. ...

Recognizing the need for an improved cellular material manufacturing process, the authors follow a systematic design method (posed by Pahl and Beitz) to address the inherent limitations imposed on designer freedom by existing manufacturing techniques. After identifying unique requirements of a cellular material manufacturing process, several solution principles are systematically generated following functional decomposition, working principle ideation, the formulation of working structures (via morphological matrices), and a preliminary selection exercise. Following preliminary embodiment, a principal solution is identified through the formulation and solution of a selection Decision Support Problem. As a result of this design effort, a novel layered manufacturing process capable of realizing metallic cellular materials (specifically, the three-dimensional printing of metal oxide parts followed by a thermal-chemical conversion postprocess) is realized. Another result of this design process is the insight gained from the systematic requirements-driven (or “application-pull”) design of a layered manufacturing process.

A Computer-Aided Platform for Simultaneous Process Synthesis and Intensification

Need of use of computer technology for conceptual design of control systems' elements for electric power system was proved. The known approaches to the solution of this task are analysed and need of their development is proved. New approach to conceptual design of control systems' elements on the basis of the fractal theory is observed. Two types of self-similarity for functional fractals were defined: rigid and non-rigid self-similarity. Use of this approach allows to model sensors of new generation, in particular, multiifunctional sensors.