Plant layout models

Figure 3-3 shows a view of a typical model for an industrial plant. Errors in a plant layout are easily located when three-dimensional models are used, since the operations and construction engineers can immediately see errors which might have escaped notice on two-dimensional templates or blueprints. In addition to increasing the efficiency of a plant layout, models are very useful during plant construction and for instruction and orientation purposes after the plant is completed. 

Figure 1.13 Isometric Mew of Preliminary 3-D Plant Layout Model for DME Process (Reproduced by Permission of Cadcentre, an Aveva Group Conpany, from their Vantage/ PDMS Software)...

The preceding case studies have shown that gas explosion calculations inside realistic process plant layouts are possible, using the state-of-the-art 3D computer model, named EXSIM. The peak pressures found in the four chosen calculation cases are summarized in the following table ... 

Paton [15] reports total model costs of 0.4 to 1.0 percent of erected plant costs for a 1 million plant. These are actual costs and do not reflect profits. Material costs are less than 10 percent of total model costs, and usually less than 5 percent. For a. 30 million plant model costs run as low as 0.1 percent. These are for models which include plant layout, piping layout, and piping details. If simpler models are used the costs should be less. 

Figure 1-16A. Simple block model plant layout. Courtesy of Socony Mobil Oil Co. Inc.

The use of computer models to assist in plant layout decisions can often be helpful, but a clear understanding of what they can and cannot do is needed. Used blindly, they can lead to solutions which are, in some sense, optimal but which have little practical merit. 

Historically, modeling techniques have had little impact on the problem of designing plant layouts. This has been for two reasons. First, the calculations are difficult, and second, practical constraints and considerations essential to the decision are often ignored. 

The recent introduction of inexpensive desktop computers has allowed their extensive use throughout many companies. The standard spreadsheet packages which accompany these machines enables the above data to be laid out in an interactive way, so that what if situations can be explored at the planning stage and the implications of, for example, market trends in the food industry, to be examined over the long term for its effect on the plant layout. The model may include a factor to take into account improvements in technology and working practices in both the office and factory. 

Cardboard cut-outs of the equipment outlines can be used to make trial plant layouts. Simple models, made up from rectangular and cylindrical blocks, can be used to study... 

The model of the plant describes the plant layout and the numbers and properties of the equipment and defines the operations that can be performed on... 

This 3-D layout model is a valuable draft but it has to be revised during detailed engineering. The tool is important for the micro world if in the future micro structured reactor plants become more and more standardized. In this case, standardized autorouter tools could help to automate the time-consuming part of detailed engineering in complex micro structured reactor plants. 

Scale model showing details of plant layout. (Courtesy of the M. W. Kellogg Company.)... 

Templates, or small cutouts constructed to a selected scale, are useful for making rapid and accurate layouts, and three-dimensional models are often made. The use of such models for making certain a proposed plant layout is correct has found increasing favor in recent years. 

Detailed design engineering of process equipment, piping systems, control systems and offsites, plant layout, drafting, cost engineering, scale models, and civil engineering ... 

In contrast to these generic tools, the second group of domain-specific software tools addresses certain tasks during the design process in the chemical engineering domain. They can roughly be classified as data retrieval, synthesis, and analysis tools. A typical example for data retrieval tools are physical property systems [1048, 1053[. Synthesis tools include flowsheet synthesis [951, 1039], plant layout and pipe routing [955], model development ]54, 558] or even solvent selection [7.37]. The most prominent examples of analysis tools are process simulators for steady-state ]518, 556, 1046] and dynamic simulation ]288, 518, 916]. 

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