Purchasing

The specific purchasing decisions include the make-buy decision for components and products, global location of sources for manufacturing and distribution facilities, and coordination with suppliers to maximize mutual benefit. 

---

There can be an element of maintenance costs that is fixed and an element which is variable. Fixed maintenance costs cover routine maintenance such as regular maintenance on safety valves which must be carried out irrespective of the rate of production. There also can be an element of maintenance costs which is variable. This arises from the fact that certain items of equipment can need more maintenance as the production rate increases. Also, royalties which cover the cost of purchasing another company s process technology may have different bases. Royalties may be a variable cost, since they can sometimes be paid in proportion to the rate of production. Alternatively, the royalty might be a single-sum payment at the beginning of the project. In this case, the single-sum payment will become part of the project s capital investment. As such, it will be included in the annual capital repayment, and this becomes part of the fixed cost. 

Utility costs vary enormously. This is especially true of fuel costs. Not only do costs vary considerably between different fuels (coal, oil, natural gas), but costs also tend to be sensitive to market fluctuations. Contractual relationships also have a significant effect on fuel costs. The price paid for fuel may depend very much on how much is purchased. 

The factors fp and fj have not been applied to installation costs because installation costs are not a simple function of purchase cost. Although process piping and fittings made for the same unusual conditions are proportionally more expensive, labor, foundations, insulation, etc. are not. Furthermore, only about 70 percent of piping is directly exposed to process fluid. The balance is auxiliary or utility piping made of conventional materials. 

Example A.4.1 The purchased cost of a distillation column is 1 million, and the reboiler and condenser are 100,000. Calculate the annual cost of installed capital if the capital is to be annualized over a 5-year period at a fixed rate of interest of 5 percent. 

Except in the United Slates of America, this book is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, re-sold, hired out, or otherwise circulated without the publisher s prior consent in any form of binding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser... 

A comparison of overall treatment costs (purchase and refining) for several crude oils enables the refiner to establish his feedstock requirements and to satisfy the market needs under the most economical conditions. 

When a customer agrees to purchase gas, product quality is specified in terms of the calorific value of the gas, measured by the Wobbe index (calorific value divided by density), the hydrocarbon dew point and the water dew point, and the fraction of other gases such as Nj, COj, HjS. The Wobbe index specification ensures that the gas the customer receives has a predictable calorific value and hence predictable burning characteristics. If the gas becomes lean, less energy is released, and if the gas becomes too rich there is a risk that the gas burners flame out . Water and hydrocarbon dew points (the pressure and temperature at which liquids start to drop out of the gas) are specified to ensure that over the range of temperature and pressure at which the gas is handled by the customer, no liquids will drop out (these could cause possible corrosion and/or hydrate formation). 

If the gas purchaser is a company which distributes gas to domestic and industrial end users, he typically wants the producer to provide... 

The better the producer can meet these two requirements, the higher the price paid by the purchaser is likely to be. 

Market forces determine the demand for a product, and the demand will be used to forecast the sales of hydrocarbons. This will be one of the factors considered by some governments when setting the production targets for the oil company. For example, much of the gas produced in the South China Sea is liquefied and exported by tanker to Japan for industrial and domestic use the contract agreed with the Japanese purchaser will drive the production levels set by the National Oil Company. 

The demand for domestic gas changes seasonally in temperate climates, and production levels reflect this change. For example a sudden cold day in Northern Europe causes a sharply increased requirement for gas, and gas sales contracts in this region will allow the purchaser to demand an instant increase (up to a certain maximum) from the supplier. To safeguard for seasonal swings, imported gas is frequently stored in underground... 

The tests concluded that it was possible to use real time X-ray to inspect incoming frozen fish blocks 100% and giving a completely accurate assessment of the quality of the blocks to enable the factory to calculate the correct purchase price as a function of the bone content. 

NAMD [7] was born of frustration with the maintainability of previous locally developed parallel molecular dynamics codes. The primary goal of being able to hand the program down to the next generation of developers is reflected in the acronym NAMD Not (just) Another Molecular Dynamics code. Specific design requirements for NAMD were to run in parallel on the group s then recently purchased workstation cluster [8] and to use the fast multipole algorithm [9] for efficient full electrostatics evaluation as implemented in DPMTA [10]. 

Molecular modelling used to be restricted to a small number of scientists who had access to the necessary computer hardware and software. Its practitioners wrote their own programs, managed their own computer systems and mended them when they broke down. Today s computer workstations are much more powerful than the mainframe computers of even a few years ago and can be purchased relatively cheaply. It is no longer necessary for the modeller to write computer programs as software can be obtained from commercial software companies and academic laboratories. Molecular modelling can now be performed in any laboratory or classroom. 

Tliesc gliiss sections for fractionating columns may be purchased from Messrs. Quicktit Quartz, Ltd., Quickfit Works, Stone, Staffs, ST15 OBG. 

G. A. R. Kon Jour. Chem. Soc.., 1930, 182) described a modification of the Perkin triangle having only two taps instead of the three described above. It may be purchased from Quickfit Quartz, Ltd., Quickfit Woiks, Stone, Staffs. 

It should be noted that a number of different enzyme preparations can now be purchased directly from manufacturing chemists. It must be emphasised that the activity of an enzyme, whether purchased or prepared in the laboratory, may vary between rather wide limits. The activity is dependent on the source of the enzyme, the presence of poisons and also on the temperature. It appears, for example, that the quality of horseradish peroxidase depends upon the season of the year at which the root is obtained from the ground. It cannot be expected therefore that all the experiments described below will work always with the precision characteristic of an organic reaction proceeding under accurately known conditions. 

Pyrex glass is preferable, but this requires an oxy-coal gas blowpipe for manipulation. Suitable melting point tubes may be purchased from dealers in scientific apparatus or chemicals. It is, however, excellent practice, and an essential part of his training, for the student to learn to prepare bis own capillary tubes. 

However, where small quantities of liquids are involved, a column filled with glass helices will probably give the best results and the cost will not be unduly high. Rings in stainless steel and other metals can be purchased in sizes from to i. ... 

Reasonably pure solvents are required for many organic reactions and for recrystaUisations methods for obtaining these from commercial products will accordingly be described. Frequently, the pure solvent (e.g., the analytical reagent) can be purchased, but the cost is usually iiigh, particularly if comparatively large volumes are required. Furthermore, it is excellent practice for the student to purify inexpensive commercial solvents. 

Absolute ethyl alcohol. Ethyl alcohol of a high degree of purity is frequently required in preparative organic chemistry. For some purposes alcohol of ca. 99 -5 per cent, purity is satisfactory this grade may be purchased (the absolute alcohol of commerce), or it may be conveniently prepared by the dehydration of rectified spirit with quicklime. Rectified spirit is the constant boiling point mixture which ethyl alcohol forms with water, and usually contains 95 6 per cent, of alcohol by weight. Wherever the term rectified spirit is used in this book, approximately 95 per cent, ethyl alcohol is to be understood. 

Toluene. Toluene, e from sulphur compounds, may be purchased. If required dry, it is treated with anhydrous calcium chloride, followed by sodium wire (see under Benzene, 15). 

An account will be given in this and the two following Sections of a number of inorganic reagents which find application in organic chemistry. No attempt will be made to describe the preparation of those reagents which can be purchased at a reasonable cost. In some cases, where the purified reagents are somewhat expensive, the methods of purification from the technical products will be outlined. 

Solids by solvents. The various forms of Soxhlet apparatus illus trated in Section 11,44 can be purchased with ground glass joints. A simplified form, in which the fragile side tubes are absent, is shown in Fig. II, 58, 1. The material to be extracted, if of granular form, may rest upon a sintered glass disc or upon a removable septum ... 

The yield of iso-propylbenzene is influenced considerably by the quality of the anhydrous aluminium chloride employed. It Is recommended that a good grade of technical material be purchase in small bottles containing not more than 100 g. each undue exposure to the atmosphere, which results in some hydrolysis, is thus avoided. Sealed bottles containing the reagent sometimes have a high internal pressure they should be wrapped in a dry cloth and opened with care. 

---