Economic evaluation structure design

The initial aim of the procedure is to generate a reasonable base case design that can be used for preliminary economic evaluation of the process. This can subsequently be optimized and/or compared with any process alternatives that are identified. The complete process is always considered at each decision level, but additional fine detail is added to the structure of the flowsheet at any stage. Established heuristics and equipment selection procedures are used together with new process synthesis insights to guide each flowsheet decision. 

Develop final Perform structural design of analysis of component acceptable accuracy Determine structural response—stresses, support reactions, deflections, and stability—based on a structural analysis of acceptable accuracy. Determine acceptable accuracy based on economic value of component, consequences of failure, state-of-the-art capability in stress and stability analysis, margin of safety, knowledge about loads and materials properties, conservatism of loads, provisions for further evaluation by prototype testing... 

Commercialization of a supercritical carbon dioxide processed food product requires the successful application of five sequential steps 1) application of high pressure CO2 phase equilibria and fluid dynamics theory 2) knowledge of the botanicals structure and chemistry 3) performance of the "process design protocol" 4) preliminary process design and economic evaluation and 5) design, construction and start-up of the commercial-scale plant. Many decisions made during the early steps have large impacts on commercial plant performance capabilities and economic efficiency. The impact on commercial plant performance and economics should be factored into decisions made at every commercialization step. 

Structured multi-scale design methodology should be developed in such as way as to permit reliable qualitative and quantitative techno-economic evaluation of structured multi-scale process systems for both existing and potential production processes. 

Revise preliminary design of component Evaluate preliminary design Review economics and suitability of materials and process based on preliminary proportions. Consider overall compatibility and practicality of all materials and parts in component as a system Does it meet functional and performance requirements Is it compatible with other components that may interact with it, relative to effects of expansion and contraction, structural support or movement, fire safety, etc. ... 

All structures are subject to foundation design. In some cases piled foundations are preferable. Heavy structures with very strict specifications regarding (differential) settlement will normally require a piled foundation when constructed on reclaimed land overlying soft subsoil. Small sized structures of limited weight can generally be supported by shallow foundations. Based on a technical and economical evaluation of the structural and reclamation design, the decision whether a piled foundation is required should be made in an early phase of the project. 

This section provides a basis guidance on the art of economic evaluation of the particulate factors of corrosion-control appreciation, without compromising the complete integrated corrosion control of the whole project. There is also special guidance regarding corrosion control that should be considered by the designer of structures, equipment, and piping systems. 

Once the flowsheet structure has been defined, a simulation of the process can be carried out. A simulation is a mathematical model of the process that attempts to predict how the process would behave if it were constructed (Figure 1.2b). Having created a model of the process, the flowrates, compositions, temperatures and pressures of the feeds can be assumed. The simulation model then predicts the flowrates, compositions, temperatures, and pressures of the products. It also allows the individual items of equipment in the process to be sized and predicts, for example, how much raw material is being used or how much energy is being consumed. The performance of the design can then be evaluated. There are many facets to the evaluation of performance. Good economic performance is an obvious first criterion, but it is certainly not the only one. 

Hi) Evaluation. Economic potential is computed by subtracting the costs for the reaction system and gas compressor from the economic potential computed at the input/output structure level. To compute the costs for those units, several assumptions, such as the reactor type and the kinetic model, should be made. More detailed algorithms and example applications are available in Douglas design text (Douglas, 1988). 

Heuristic methods were developed by well-experienced engineers and researchers. The first attempt to develop a systematic heuristic approach for the synthesis of multicomponent separation sequences was made by Siirola and Rudd. Common example is hierarchical heuristic approach.Heuristic rules are applied at five design levels to generate and evaluate the alternatives using economic criteria. The hierarchical heuristic method emphasizes the strategy of decomposition and screening. It allows for a quick location of flowsheet structures that are often near ... 

However, as we have demonstrated in our previous examples, this design is usually not the one that provides the best control, i.e., the least variability of product quality. What we need is a way to incorporate quantitatively (in terms of dollars/year) this variability into the economic calculations. We discuss in this section a method called the capacity-based approach that accomplishes this objective. It should be emphasized that the method provides an analysis tool, not a synthesis tool. It can provide a quantitative assessment of a proposed flowsheet or set of parameter values or even a proposed control structure. But it does not generate the besf flowsheet or parameter values it only evaluates proposed systems. 

There are a host of conventional control structures, and the best choice depends on a number of factors, some of which we have already discussed the shape of the temperature profile and the sensitivity of the several flow ratios to feed composition. Economics obviously have an impact, mostly in terms of energy consumption versus control structure complexity. The control structure that minimizes energy is dual-composition control. But it is more complex than a simple single-end control structure. Therefore, we must evaluate how much money is lost by using a more simple structure. In areas of the world where energy is inexpensive, both the optimum design and the appropriate control structure are different than in areas with expensive energy. 

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