Capital required spares

Capital requirements ate affected indirectly by design reliability in that larger safety factors ate applied when design methods are less reliable. There is also a tendency to install more extensive control systems and more spare backup equipment when there is uncertainty in the reliability of the design methods. Such practices significantly increase the capital requirement for those methods with tow design reliability. The design reliability of the various separation processes is discussed in Section 22.2-4. 

The choice of whether to purchase or generate electricity and decisions on generator or cable configuration and sparing are often not obvious. An economic study evaluating capital and operating costs and system reliability of several alternatives may be required. 

The other drawback is simply one of economics. Because pumps come in a variety of shaft sizes and speeds, the use of this type of seal requires inventorying several sizes of spare springs, which ties up capital. 

Consideration of factory operation adds further advantages for the steady catalyst. The changing of the charge is often an expensive job and sometimes an unpleasant one, perhaps involving drilling out. It may also require the purchase of a separate reactor body so that a complete filled spare unit is always available. The extra capital inventory can be substantial. The... 

All recoating options include a full leak check and back pan nickel replacement. Spares can be made available on a lease basis to minimize capital investment while eliminating production losses. Anodes are inspected and, upon customer approval, repaired by using De Nora s proprietary techniques with different anode coatings available for any potential or oxygen evolution requirement. Each coating has different characteristics in resistance to shutdowns and iron, hydrogen overpotential, and price that can be tailored to specific plant needs. 

Working capital funds, Cwc. are needed to cover operating costs required for the early operation of the plant, including the cost of the inventory and funds to cover accounts receivable. Because they involve the costs of the raw materials and the values of the intermediates, products, and byproducts, the working capital is normally estimated in connection with the calculation of the operating Cost Sheet , which is presented in Table 17.1 and discussed in Section 17.3. Note that funds are usually allocated for a spare charge of catalyst, often kept in a warehouse, as a backup in case an operating problem causes the catalyst to become ineffective. 

JIT is followed when a large inventory can block a lot of working capital. Procurement of various items is planned and executed in such a manner that they arrive at point of application just when they are to be used/fed into the system. This needs very accurate estimation of the rates of consumption time required for procurement (testing samples at vendor s works, loading, transportation, and unloading at site) is necessary for the success of this arrangement. However, a reasonable stock of the spares shall be available in the stores as matter of abundant precaution. 

Selecting the most economical method of evaporation requires knowledge of the costs of energy, capital, operating labor, spare parts, and maintenance over the life of the system. Energy and capital costs dominate and show the... 

Capital costs for vapor compression systems are usually higher than for multiple-effect systems, because they are usually designed for a lower temperature difference across the evaporator. As a result, greater heat transfer surface is required. In addition, the compressor and drive are relatively expensive. Equipment costs are affected by variables such as feed properties, materials of construction, available energy supply, and calandria type. Expected maintenance and necessary spare parts must be also evaluated. Heat exchangers must be provided to exchange heat between feed and condensate and between feed and product. Other costs that must be considered, but are less easily defined, are the penalty for interrupted operation during repairs and the part load response. 

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