Plant design location

In Section 10.0, we have discussed process design and processing equipment rather than the layout oi production facilities. Once a process scheme has been defined, the fashion in which equipment and plant is located is determined partly by transportation considerations (e.g. pipeline specifications) but also by the surface environment. 

Dehydration. Use of molecular sieve driers for final clean-up of the carbon oxides and water in the synthesis gas to less than 1 ppm levels has gained prominence in low energy ammonia plant designs. The sieves are usually located at the interstage of the synthesis gas compressor to reduce volume requirements. The purified make-up gas can then be combined with the recycle and routed direcdy to the converter. 

For by-product coke ovens, it is general practice to blend two or more types of coals that have complimentary technical as well as economic characteristics. Because most by-product coke plants are located near the large industrial users of the coke and by-products, coals usually have to be transported from the coal mines to the coke plants. Thus coal blends are designed on integration of coke quaUty needs, by-product quaUty needs, coal costs, transportation costs, impacts of productivity, and impacts on the coke ovens themselves. The physical behavior of coal blends during coking can damage coke ovens. 

Customer" Expectations. Keep in mind that the output of your PSM systems design must address the needs of a range of "customers," including senior management, facility and other operating personnel, and the PSM team itself. As you approach designing the PSM system, you may want to revisit their expectations. Systems will also have to reflect issues such as plant size, location, type of operation, and types and quantities of materials used. 

Provision for protection and safety equipment should be incorporated in the original plant design. The size of the plant, nature of the hazards, and the e.xposure will determine the amount, kind, and location of this equipment. 

Many s)mbols are pictorial which is helpful in representing process as well as control and mechanical operations. In general, experience indicates that the better the representation including relative locating of connections, key controls and even utility connections, and service systems, the more useful will be the flowsheets for detailed project engineering and plant design. 

While ideally structures should be designed and fabricated so that environment-sensitive cracking is avoided, in practice it is sometimes necessary to live with the problem. This implies an ability to detect and measure the size of cracks before they reach the critical size that may result in catastrophic failure. Such inspection has important implications for plant design, which should be such as to allow inspection at relevant locations. The latter are regions of high residual stress (welded, bolted or riveted joints) and regions of geometrical discontinuity (notches, crevices, etc.) where stress or environment concentration may occur. 

Plant Layout, Location, Design and Construction. For information on the special techniques required in the loading and fabrication of expls pertinent to ammo plant layout and design, see the entry under that title in Vol 7, L46-L to L57-L For what has been done to accomplish modernization of munitions plants now extant, see Modernization Engineering Project for US Army,Ammunition Plants1 in this Vol, M.147-L to Ml48-R. The problem of pollution created by ammo plants is examined in an article under this topic in this Vol... 

Liston (Ref. 27) provides useful checklists for equipment and building siting and layout for safety purposes, as well as other safety-related criteria for plant design. These checklists address economic considerations and facility geographical location, site selection, layout, and unit plot planning factors. 

When the vendor is not reqnired to monnt the driver, he shall deliver the fully machined half conpling to the driver manufacturer s plant or any other designated location, together with the necessary instructions for monnting the half coupling on the driver shaft. 

This brief outline suggests that the plant-design project involves a wide variety of skills. Among these are research, market analysis, design of individual pieces of equipment, cost estimation, computer programming, and plant-location surveys. In fact, the services of a chemical engineer are needed in each step of the outline, either in a central creative role, or as a key advisor. 

Before proceeding any further with the development of a process design and its associated economics, it will be desirable to consider an overall view of the various functions involved in a complete plant design. Particular emphasis in this discussion will be placed on important health, safety, loss prevention, and environmental considerations. Other items that will be noted briefly include plant location, plant layout, plant operation and control, utilities, structural design, storage, materials handling, patents, and legal restrictions. 

---