Materials of construction costs

Information on manufacturing processes, equipment parameters, materials of construction, costs and the physical properties of process materials are needed at all stages of design from the initial screening of possible processes, to the plant start-up and production. 

It should be emphasized that the factors in Table 2.2 are average and only approximate and will vary, amongst other things, according to the type of equipment. As an example, consider the effect of materials of construction on the capital cost of distillation columns. Table 2.3 gives materials of construction cost factors for distillation columns. 

Fm Material of construction cost factor Dimensionless V. Asset value at end of year ... 

Fm = material-of-construction cost factor Fp = design pressure cost factor... 

Throughout the history of human civilization, improvements in materials of construction have been sought. Starting with the building of some of humankind s earliest monuments, mud was combined with straw to improve the performance and strength of the composite structure. Hence, the desire to use inexpensive materials to effectively upgrade the performance of commodity materials is not a new idea. Today, with strong competition between the various materials of construction, cost-effective materials have been continuously developed and expanded. 

Raw materials efficiency. In choosing the reactor, the overriding consideration is usually raw materials efficiency (bearing in mind materials of construction, safety, etc.). Raw material costs are usually the most important costs in the whole process. Also, any inefficiency in raw materials use is likely to create waste streams that become an environmental problem. The reactor creates inefficiency in the use of raw materials in the following ways ... 

If the problem is dominated by equipment with a single specification (i.e., a single material of construction, equipment type, and pressure rating), then the capital cost target can be calculated from Eq. (7.21) with the appropriate cost coefficients. However, if there is a mix of specifications, such as different streams requiring different materials of construction, then the approach must be modified. 

Thus the weighted network area AJ itwork is 9546 m. Now calculate the network capital cost for mixed materials of construction by using AI t ork... 

Hall, S. G., Ahmad, S., and Smith, R., Capital Cost Target for Heat Exchanger Networks Comprising Mixed Materials of Construction, Pressure Ratings and Exchanger Types, Computers Chem. Eng., 14 319, 1990. 

Equation (F.l) shows that each stream makes a contribution to total heat transfer area defined only by its duty, position in the composite curves, and its h value. This contribution to area means also a contribution to capital cost. If, for example, a corrosive stream requires special materials of construction, it will have a greater contribution to capital cost than a similar noncorrosive stream. If only one cost law is to be used for a network comprising mixed materials of construction, the area contribution of streams requiring special materials must somehow increase. One way this may be done is by weighting the heat transfer coefficients to reflect the cost of the material the stream requires. 

While the principal value of the book is for the professional chemist or student of chemistry, it should also be of value to many people not especially educated as chemists. Workers in the natural sciences—physicists, mineralogists, biologists, pharmacists, engineers, patent attorneys, and librarians—are often called upon to solve problems dealing with the properties of chemical products or materials of construction. Eor such needs this compilation supplies helpful information and will serve not only as an economical substitute for the costly accumulation of a large library of monographs on specialized subjects, but also as a means of conserving the time required to search for... 

Materials of Construction. Tanks are constmcted from a number of materials based on cost and availabiHty of the material, ease of fabrication, resistance to corrosion, and compatibiHty with stored fluid. Sometimes specialized composites and techniques are used in tank constmction. These are the exception. 

Typical methods are those of F. C. Zevnik and R. L. Buchanan [Chem. Eng. Progi , 59, 70-77 (Feb. 1963)] and J. H. Taylor Eng. 6-Proc. Econ., 2, 259-267, 1977). The former is mainly a graphical method of estimating the cost per functional unit (Cp) based on the capacity, the maximum pressure, the maximum temperature, and the materials of construction. The Taylor method requires the determination of the costliness index, which is dependent on the complexity of the process. A simpler method was suggested by S. R. Timms (M.Phil. thesis, Aston University, England, 1980) to give the battery hmits cost for gas phase processes only in U.S. dollars with a Marshall and Swift index of 1000. The simple equation is... 

The stirring produces the end product in the desired divided-sohds form. Hence, it is frequently termed a granulator or a ciystaUizer. A variety of factoiy-made sizes in various materials of construction are available. Initial cost is modest, while operating cost is rather high (as is true of all batch devices), but the ability to process gummy burdens and/or simultaneously effect two unit operations often yields an economical application. 

Materials of construction Relative cost per ft of tray area (based on carbon steel = 1)... 

Of all continuous filters, the vacuum disk is the lowest in cost per unit area of filter when mild steel, cast iron, or similar materials of construction may be used. It provides a large filtering area with minimum floor space, and it is used most in high-tonnage dewatering apphcations in sizes up to about 300 m" (3300 ft") of filter area. 

The primaiy purpose of materials selection is to provide the optimum equipment for a process application in terms of materials of construction, design, and corrosion-control measures. Optimum here means that which comprises the best combination of cost, life, safety, and reliability. 

General Collection efficiency Legal limitations such as best available technology Initial cost Lifetime and salvage value Operation and maintenance costs Power requirement Space requirements and weight Materials of construction Reliability Reputation of manufacturer and guarantees Ultimate disposal/use of pollutants... 

The usual estimating technique is to collect equipment pricing information from other projects and correlate this data by size, weight, pressure rating, and/or materials of construction. Each piece must be adjusted for inflation to bring all costs to one base time. Adjusting costs for inflation is discussed later under the heading, " Construction Cost Indexes. ... 

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