Conceptual design phase

The involvement of the final users in the conceptual design phase and during the whole development phase is crucial [40]. Users are often not able to specify all their expectations and requirements during the first stages of the system development, but periodic and continuous revisions of evolved prototypes allow them to evaluate and contribute to the improvement... 

An exact calculation of inventory is difficult in the conceptual design phase, since the size of equipment is not usually known. The mass flows in the process are however known from the design capasity of the process. Therefore it is practical to base the estimation of inventory on mass flows and an estimated residence time. Consequently the inventory has been included to the ISI as a mass flow in the ISBL equipment including recycles with one hour nominal residence time for each process vessel (e.g. reactor, distillation column etc). For large storage tanks the size should be estimated. The total inventory is the sum of inventories of all process vessels. 

Many different alternative process configurations can be created for a process in the conceptual design phase. In choosing the most feasible alternative safety should be one of the major evaluation criterias. Therefore information on the safety features of alternative process structures are needed on preliminary process design. 

The conceptual design phase is the most critical when designing inherently safer plants, since the alternative process concepts are created and analyzed in this phase. This emphasizes the need to introduce safety evaluation tools into the preliminary process design. Time and money is saved when fewer expensive safety modifications are needed during the later stages of design. 

The Inherent Safety Index, ISI, was developed to consider a wider range of factors affecting the inherent safety of the process (Ch. 8). The ISI allows the evaluation of inherent safety of process alternatives to be done in a computerized process synthesis environment. The represented synthesis approach allows the inherent safety comparison of process alternatives to be done flexibly and interactively in the conceptual design phase. 

Conceptual Design Phase 0 Design Phase 1 Design... 

The MHR is well suited for coupling to hydrogen production processes based on thermochemical water splitting and HTE. Both the Sl-based and HTE-based H2-MHR concepts have the potential to produce hydrogen safely, efficiently, and economically. Work on both concepts should continue beyond the conceptual design phase, which will provide a sound basis for a focused technology-development program that could eventually lead to commercial deployment of one or both concepts. 

Conceptual Design. During the conceptual design phase, the reaction pathway synthesis is undertaken the inherent process safety is incorporated the general... 

Studies have shown that the initial design phase actually requires a relatively small investment, which can greatly influence the nature of the product and its ultimate commercial success (Berliner and Brimson 1988). The return on investment (ROI) of the conceptual design phase was shown to be five times greater than the ROI of later development work to develop and optimise the product and manufacturing process. 

During the conceptual design phase, the design of a chromatography system has to consider the following main criteria ... 

MIDAS integrates the design process by using human performance models in the conceptual design phases of system development. Human-system integration and development enabled by the computational human performance models methodology are illustrated in Figure 20. 

Table 1 summanzes some of the major design parameters of KALIMER, which is currently under the conceptual design phase A salient feature of its key system designs is bnefly descnbed in the following[2]... 

This would entail a much more elaborate effort in die conceptual design phase that would reduce design uncertainties in the later phases. 

When requirements are updated, proven concepts might not be able to fulfill these specifications, and the design process will fail to converge to an acceptable solution. Subsequently, to reach an acceptable solution, one has to return to the conceptual design phase to develop new concepts. This is indicated by the dashed line in Fig. 1. Needless to say, this is more time consuming and costly hence, the industry tries to avoid this. 

Accurate solid-liquid equilibrium data must be obtained to evaluate the process design options for crystallization processes. These data are required in the earliest stages of the conceptual design phase and ate trecessaty for the following reasotts ... 

This approach is generally used during the conceptual design phase and is relatively an unstructured tool because of the lack or unavailability of definitive information such as functional flow diagrams and drawings [23]. PHA has proven to be an effective method to take appropriate early steps to identify and eliminate/minimize hazards when the required data are not available. The findings of PHA serve as an effective guide in potential detailed analysis. 

In conclusion then, it is important at the conceptual design phase to critically review the proposed plant instrumentation, ensure that the multi-disciplinary consequences have been considered, and (in this light), concerning expensive items, ask the following questions. 

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