Evaluation design alternatives

PFDs act as central documents for describing chemical processes. They are refined iteratively so that they eventually describe the chemical plant to be built. Simulations are performed in order to evaluate design alternatives. Simulation results are fed back to the PFD designer, who annotates the flowsheet with flow rates, temperatures, pressures, etc. Thus, information is propagated back and forth between flowsheets and simulation models. 

The literature survey phase involves the collection of existing data for the development of a preliminary model of site conditions for use in evaluating design alternatives. Some of the data that are necessary to acquire during this phase are as follows ... 

Liepa MA, Borhan A (1986) High-temperature steam electrolysis Technical and economic evaluation of alternative process designs. Int J Hydrogen Energy 11 435... 

As illustrated, based on simulation results, using the plotted graphs and screens, management can easily evaluate different design alternatives, machine and human behavior models, control systems, sensory feedback processing, and the need of a balanced server architecture, and even investigate what if scenarios further, without committing to major upfront investment. 

In order to integrate parameter scenarios and configuration alternatives and to provide comprehensive evaluation features, a Scenario Manager has been included in the prototype decision support tool. The main feature of the Scenario Manager is the capability to combine parameter scenarios and design alternatives into comprehensive main scenarios for evaluation runs (cf. Fig. 48). The standardized reports introduced in the next chapter use these main scenarios to compare the results of different evaluation runs. 

In Step 7, the planning team evaluates the data collection design alternatives and selects the most cost-effective approach that most closely meets the DQOs. Budget... 

Computer-aided design and simulation gives the process engineer the ability to evaluate more design alternatives in more detail than was... 

Once the quotes are received, compile a short list" of the more attractive bids. Evaluate the alternate quotes by comparing to experimental data, correlation predictions, or sound design criteria. Chapters 10 and 11 contain all the published information the author conld find on proprietary packings. Additional information may be available in proprietary data banka. If your data are insufficient to form a judgment, question the supplier s design basis and ask for backnp data. 

Allowing time in the early stages of design for critical reviews and evaluation of alternatives would involve studies such as an early hazard and operability (HAZOP) study, using flowsheets, before final design begins,4 Fault tree analysis, quantitative risk assessment (QRA), checklists, audits, and other review and checking techniques can also be very helpful. These techniques are extensively discussed in the technical literature and will not be discussed in detail here. 

Tier II environmental assessment is employed for flowsheet synthesis on a smaller number of design alternatives. This provides an opportunity to evaluate the impacts of separation and other units in the process in addi-... 

The human-driven character of interactive design allows the use of (1) problem-specific subjective preferences, (2) informal, qualitatively stated scientific knowledge, (3) rapid evaluation of alternatives, and (4) evolutionary design of new molecules, starting from known and existing alternatives. It provides the designer with the following facilities ... 

In the first step, the design alternatives are automatically generated using a superstructure. In the second step, the design alternatives are evaluated using the rectification body method (RBM) [5], a nonideal thermodynamic based shortcut method. Unlike simulation studies or MINLP optimization, shortcut methods allow fast evaluation of the single separation task without detailed specification of the distillation column. 

During the combination of the partial solutions, a major pivotal decision needs to be made is to determine at what scales to implement the processing tasks related phenomena. It can be microscale, or mesoscale or hybridscale (both microscale and mesoscale). Needless to say, it is the corresponding concepts and principles generated for the variations and manipulations of the processing tasks related phenomena that determine the scales of the intensified process and equipment. As a consequence, microscale, mesoscale or hybridscale devices and units are synthesized by the combination of the partial solutions. Thereby, the intensified microstructured devices, the intensified mesoscale process units, or the intensified hybridscale devices are obtained as the conceptual design alternatives from the conceptual process synthesis. The evaluation of PI results is often self-evident as long as the technical feasibility of the intensification concepts and principles can be verified. Nevertheless, once intensified process alternatives have been identified, the further detailed optimization can be performed. 

Preformulations From an industrial point of view, preformulation studies are designed to cover a wide range of properties in a short time and to learn as much as possible, but not in great depth. The studies should focus on the identification of potential problems early enough to evaluate potential alternatives to stabilize future formulations that could lead to a product. 

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 ... 

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