Preliminary Equipment Design

Overall Eactor Estimates. The next level of fixed capital estimate is based on a preliminary design that includes a flow sheet, material balances, energy balances, and enough equipment design to size all of the principal process equipment, including pumps and tanks. 

Heikkila, A-M. Hurme, M. 1998b. Inherent Safety Index for Offsite Equipment in Preliminary Process Design. Proceedings of 13th International Congress of Chemical and Process Engineering CHISA 98, Prague. 

Since fluid shear rates vary enormously across the radius of a capillary tube, this type of instrument is perhaps not well suited to the quantitative study of thixotropy. For this purpose, rotational instruments with a very small clearance between the cup and bob are usually excellent. They enable the determination of hysteresis loops on a shear-stress-shear-rate diagram, the shapes of which may be taken as quantitative measures of the degree of thixotropy (G3). Since the applicability of such loops to equipment design has not yet been shown, and since even their theoretical value is disputed by other rheologists (L4), they are not discussed here. These factors tend to indicate that the experimental study of flow of thixotropic materials in pipes might constitute the most direct approach to this problem, since theoretical work on thixotropy appears to be reasonably far from application. Preliminary estimates of the experimental approach may be taken from the one paper available on flow of thixotropic fluids in pipes (A4). In addition, a recent contribution by Schultz-Grunow (S6) has presented an empirical procedure for correlation of unsteady state flow phenomena in rotational viscometers which can perhaps be extended to this problem in pipe lines. 

Sanders, E. S. Koros, W. J. Hopfenberg, H. B. and Stannett, V, T. "Mixed Gas Sorption in Glassy Polymers Equipment Design and Considerations and Preliminary Results," Submitted for Publication, J, Polym. Sci - Phys. Ed ... 

The economic feasibility of the process should be established at this stage. Again, this is only an introductory assessment performed more to establish that the plant is not definitely a loss-maker, rather than deciding that it is a particularly attractive proposition. A full and detailed economic evaluation of the plant and process is performed later in the design study (see Chapter 6) after the process route has been finalised, a detailed equipment listing prepared, and preliminary equipment designs have been performed. The following steps need to be performed to establish the economic feasibility of the process ... 

Following completion of the mass and energy balances, preliminary equipment designs can be undertaken. The final equipment designs and specifications are completed after performing a detailed economic evaluation of the project and an energy conservation study (Section... 

Equipment design for this preliminary process evaluation involves determining the size of the equipment in terms of the volume, flow per unit time, or surface area. Some of the calculations associated with the alkylation unit are presented in the following to indicate the extent of the calculations whigh are sometimes adequate for a preliminary design. 

Before a manufacturer is contacted, the engineer should evaluate the design needs and prepare a preliminary specification sheet for the equipment. This preliminary specification sheet can be used by the engineer as a basis for the preparation of the final specifications, or it can be sent to a manufacturer with a request for suggestions and fabrication information. Preliminary specifications for equipment should show the following ... 

Apply high-fidelity models for equipment design Apply consistent design by leveraging the same validated thermophysical properties knowledge and models used in preliminary design stages... 

Other types of pilot plant, including commercial units embracing this principle, are available. Some selected vendors of pilot plants, although this is not an exclusive list, include UHDE, Thar Designs, Applied Separations, Chematur, and Separex.. Likewise, bench-scale equipment for preliminary evaluations are manufactured by such companies as Autoclave Engineers (now called Snap-Tite), Chematur, Nova Swiss, Applied Separations, Nova Sep, Thar Designs, Pressure Products, Inc., Supercritical Fluid Technologies, and Separex. 

Equipment design, as discussed in the preceding section, requires preliminary evaluation of column efficiency. There is a close conphng between geometry and efficiency. Several different efficiency terms will be nsed for tray columns, bnt the one nltimately needed for design is overall column efficiency ... 

Here we discuss only some basic aspects regarding the preliminary selection of materials with respect to equipment design and costing evaluation. More information can be found in engineering handbooks, as Perry (1997), Coulson Richardson (1993) and Ullmann s Encyclopedia (1992). The following criteria should be kept in view ... 

The first thing we used, Kurti recalls, was Dutch cloth, as I think it is called—a very fine copper gauze which has many hundreds of holes to the inch. The assistants hammered the holes even finer by hand. They tested the copper barrier not with hex but with a mixture of water vapor and carbon dioxide, in other words something much like ordinary soda-water —the first in an urgent series of experiments carried out through the summer and fall to study materials, pore size, pressures and other basic parameters preliminary to any equipment design. 

This paper first provides a brief description of the U.S. plutonium immobilization using ceramic processing. A systematic approach for identifying and solving possible technical safety issues is introduced in Section 3. Technical and other broad safety issues specifically associated with the ceramic processing for excess plutonium immobilization are summarized in Section 4. A brief conclusion is given in Section 5. It should be emphasized that the results are preliminary, since at this moment the details of the facility and equipment designs are not yet available. 

Based on the pre-conceptual designs of the U.S. ceramic process, a summary of the technical safety issues is given below. It should be emphasized that the results are preliminary and generic because the facility and equipment design details are not yet available. 

The next level of sophistication is called a study estimate and requires a preliminary process flow sheet (to be discussed in the next sub-section) and a first attempt at identification of utilities, materials of construction, and other ancillary equipment. Estimation accuracy improves to within + 30% probable error, but more time is required and the cost of the evaluation can escalate to over 30,000 for a 5 million plant. Evaluation at this level usually precedes expenditures for site selection, market evaluation, pilot plant work, and detailed equipment design. If a positive evaluation results, pilot plant and other activities may also begin. 

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