Design preliminary analysis

Note These values are intended for preliminary design analysis only and are not to be used in place of thorough product design. 

The volumetric expansion parameter S may thus be taken as 0.9675. The product distribution will vary somewhat with temperature, but the stoichiometry indicated above is sufficient for preliminary design purposes. (We should also indicate that if one s primary goal is the production of ethylene, the obvious thing to do is to recycle the propylene and ethane and any unreacted propane after separation from the lighter components. In such cases the reactor feed would consist of a mixture of propane, propylene, and ethane, and the design analysis that we will present would have to be modified. For our purposes, however, the use of a mixed feed would involve significantly more computation without serving sufficient educational purpose.)... 

To those already familiar with hazard/risk analysis methods, a "PHA" designates a Preliminary Hazard Analysis. Unfortunately, the PSM Rule uses these same letters to designate Process Hazard Analysis. In this document, PrHA will designate Process Hazard Analysis to avoid confusion with Preliminary Hazard Analysis. Note that other literature may be confusing on this issue. 

A designer, as part of his facility design analysis, should perform a hazards analysis or risk assessment of the various processes which will be conducted within the facility in order to determine what potential thermal dangers or threats exist to personnel and equipment. A hazards analysis or risk assessment will provide for the identification of potential hazards and of the necessary corrective actions/measures to prevent or control the hazard. Early in the design of a facility, the processes and equipment may be conceptual and at this stage, a preliminary hazards analysis can be performed. It is early in the design that a preliminary hazards analysis can be most helpful because its... 

Reagent selection was not an issue as NaOH/HCl were already being used. The reaction was assumed to be virtually instantaneous, eliminating steady-state considerations. A complete design analysis was not considered justified until the decision on local containment had been made. The preliminary control analysis (Section III.B.2) was therefore used as the sole design tool. As two CSTRs with 10 minutes residence time at normal flow already existed, the analysis was carried out based on n CSTRs of this size. Application of Hoyle s correlation (Eq. 

To simplify a preliminary reactor design analysis, engineers often assume that the pressure drop across a reactor is negligible and has little induence on reactor size requirements. 

The thermodynamic analysis, preliminary design of the system components, and the important accident analysis are described in the following sections... 

Both vertex analysis and the transformation analysis require a large number of deterministic analysis runs. Donders (2005) have derived the so-called short transformation from the original version by Hanss. The method reduces the number of calculations significantly with respect to the basic transformation method, but it suffer seven more from non-monotonicity. In preliminary design analysis however, results may be most valuable. 

The SF usually used based on experience is 1.5 to 2.5, as is commonly used witli metals. Improper use of a SF usually results in a needless waste of material or even product failure. Designers unfamiliar with plastic products can use tlie suggested preliminary safety factor guidelines in Table 7.3 tliat provide for extreme safety intended for preliminary design analysis only. Low range values represent applications where failure is not critical. The higher values apply where failure is... 

PHA analysis is both a system safety analysis type and technique for identifying for the early identihcation of hazards and potential mishap risk. The PHA provides a methodology for identifying and collating hazards in the system and estabhshing the initial SSRs for design from preliminary and limited design information. The intent of the PHA is to affect the DFS as early as possible in the development process. The PHA normally does not continue beyond the SSHA time frame. 

Reliability of the Brayton system includes the turbomachinery as well as the rest of the gas loop. Use of installed spares will increase system resiliency in the event of a turbine failure, but will also create additional failure modes which need to addressed in the design process. Preliminary reliability analysis suggests that there is no realizable reliability benefit to adding spare Brayton loops. 

It is important that the stated needs he real needs. A truly great design may be worthless if it duplicates other known designs or if it solves a problem that does not impact many people. If it is a product that is being designed, it may be difficult to predict the mass appeal and the resulting marketability of a proposed design. A preliminary market analysis will usually identify the prospective users and statistics about comparable devices or methods and volume of sales. 

Capital Investment. Erom the viewpoint of a project, all of the capital that must be raised is external capital. Equity capital is the ownership capital, eg, common and preferred stocks or retained cash, whereas debt capital consists of bonds, mortgages, debentures, and loans. Nearly all investment involves a mixture of both types so as to maximize the return on investment (21). The debt ratio (debt/total capital) for the chemical industry is typically over 30%. Because financial details are not well known during the preliminary phases of project analysis, the investment is viewed simply as the total capital that must be expended to design and build the project. 

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