Plant Nlanagement Designing good construction and proper costs into the plant eases management problems by
F.
Drew Mayfield
of the most important prin0 ciples of good management is to provide a well-designed, soundly conNE
structed plant and related facilities a t a reasonable investment cost, and one which can be operated with low operating expenses and a minimum of lost production time. This does not differ from the principle of providing a workman with the proper tools and a proper place to perform his n-ork. With the proper tools and proper work shop management’s problems are eased greatly, leaving more time in which to plan, to shape a good organization, to attract competent personnel, and to create and maintain good team spirit in the plant. This design and construction principle is a mighty big order to try to fulfill, The following thoughts high light some principles that should be helpful in achieving this goal. Equipment standardization reduces cost
Standardization of equipment such as pumps, reboilers, condensers, exchanger tubes, instruments, control valves, electric gear, and even gaskets can be extremely valuable. This can cut initial plant cost, as well as reduce lost production time, simplify maintenance and the training of operating and maintenance personnel to become familiar with different equipment items, ease revisions of the plant under expansion or process revisions, and clarify spare parts and spare equipment inventory problems. Even stocking complete sets of spare equipment items for critical services becomes feasible a t reasonable cost. One seldom recognized feature of such standardization is the use and occupancy (U&O) insurance benefit (business interruption). Proper recognition of such standardization should be made by the underwriters, and in some cases is properly recognized by the underwriters, in order to ease the problem of rebuilding a plant after a loss is incurred. August 1955
Lost operating time is correspondingly less, thereby reducing the U&O insurance cost. As examples of such standardization, reboilers can be limited to a few standard sizes with complete interchangeability in each size. Sometimes condensers and heat exchangers can be standardized in a similar manner. A single size exchanger tubing can be used for all services with lengths standardized to the one stock length or as cut from this standard stock length; thus, it is only necessary to stock one tube size and length. Control valves can be limited to a moderate number of sizes and flange ratings, varying the trim for different capacity needs. A single temperature instrument can be purchased with minor internal modification for control service or for multiple point recording service. Similar standardization can be employed for the flow control and flow recording instruments. Such standardization makes the spare parts problem less complicated and even more important, facilitates the problem of training personnel in the operation and maintenance of these units.
When I&EC’s managing editor has process engineering problems he wants to explore, Drew Mayfield’s name almost invariably comes up. Dr. Mayfield is a native Texan, and received his doctorate in chemical engineering from the University of Texas. H e worked for Phillips; for Dow in Midland, Mich., and in Freeport, Tex., for five years; and for Celanese Corp. of America for seven years. With Dow and Celanese, Drew worked in development, new plant design, simplification of plants, and cost reduction. H e left Celanese to go to Baton Rouge, where he was in from the ground up on the building of Foster Grant Co.’s new styrene plant. When construction was completed, he became plant manager. Drew’s first-hand experience at a time when standardization is rapidly becoming a byword in the chemical industry has led to some very worth-while observations.
Boiler controls can make use of all these standard process instruments with excellent results. Electric gear become less complex with across the line starters limited to a few sizes such as 7.5, 25, and 50 horsepower (all 440 v.). In many cases a single first quality gasket material can be successfully used for all services in the plant. With only one gasket material on hand, it is impossible for a pipe fitter or mechanic to use an inferior gasket material in any service. It is readily recognized that the installation of improper gasket material can lead to leaky flanges, and such leaks can cause loss of valuable material, introduce a fire hazard, and even force a plant shutdown for repairs. The very small amount of money that can be saved by using a cheaper gasket material in the milder services is not considered worth the risk of possible misuse of gasket material made possible by the mere presence in the plant of material inferior for the more critical service. Ironically enough, these more critical services which require the better gasket material are the very ones that can lead to serious losses in the form of leaks, fire hazard, and lost production time. End suction horizontal pumps can often be limited to two or three sizes, and sometimes these can be purchased with identical bearing cradles and rotating elements, differing only in the hydraulic pieces (suction bell, casing piece, and impeller). Different types of impellers in the same pump are often available, easing the problem of meeting the varying needs of gallons per minute, head, and net positive suction head performance. Such pump standardization sometimes permits the stocking of a single precut pump packing material for all services in the plant. Instrumentation reduces cost
Good instruments properly applied and maintained are vastly superior to operators for steady control of a proc-
INDUSTRIAL AND ENGINEERING CHEMISTRY
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I Plant Management Cuts consumption of nickel 50% with
GIRDLER ,..s , ~
ess and, therefore, maximum throughouts and best quality of product. Certainly through use of instruments the human error factor is minimized, and the personality factor is largely eliminated. Standardization of these instruments eases the problem of training operating and maintenance perinstruments. sonnel in the use and care of these Elimination of structural steel reduces costs
at Celaitese Plant, Bishop, Texas APPLICATION: Hydrogenation, employing a nickel type catalyst. TECHNICAL SERVICE: Girdler engineers suggested installation of a supplementary G-12 catalyst case for further purification of the hydrogen. RESULTS: Has cut consumption of expensive hydrogenation catalyst in half. Technical personnel of the Girdler Catalyst Department will gladly assist you in your catalyst problems. Write for a copy of Bulletin G 260.)
*GIRDLER,
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A D I V I S I O N OF N A T I O N A L CYLINDER GAS COMPANY
L O U I S V I L L E 1, K E N T U C K Y GAS PROCESSES D I V I S I O N : New York, San Francisco VOTATOR D I V I S I O N : New York Atlanta Chicago San Fruncirco I n Canada: Girdler Corporation of Canada Limited, Toronto For further information, circle number 92 A on Readers’ Service Card, page 115 A
92 A
To reduce plant initial cost, initial painting and annual painting expenses, and fire insurance rates, the structural steel installation should bc hcld to a minimum. Some insurance underwriting groups base the U&O (business interruption) rate on the fire and extended coverage rate, the business interruption rate being in the realm of 1.5 times the fire rate. This may mean that the annual U&O premium may be several times the annual fire and extended coverage premium. It is thus very important in such cases to get the fire rate down, as each dollar saved on fire insurance amounts to many more dollars in total fire plus U&O savings. Where condensers have to be mounted high in the air for some reason, they can be supported from the top of fractionating columns and absorbers. Fractionating columns can normally survive a fire fairly well due to their insulation and the additional protection offered by liquids in the column cooling the tower by boiling through the pop valve. The structural elements from the top of the column to the supported equipment can be flame protected with concrete or Gunite. Those structural supports required 15 to 30 ft. above grade can be flame protected with concrete or Gunite. Minimizing failure of supporting structures under fire conditions is thus accomplished, fire insurance rates reduced, and the annual paint expense on structures eliminated. Structural steel is expensive to protect and maintain under mildly corrosive or heavily corrosive atmospheres, particularly where fire hazards exist. Painting must be done frequently and is expensive. Some insurance underwriters are very critical of structural steel in hazardous areas that is not protected from fire by concrete or autoniatic water sprays. I n
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 47, No. 8
addition to the initial cost of structural steel, it is obvious that its mere presence involves added expense either in the form of capital cost for concrete fireproofing on the one liarid, or capital cost for water sprays with annual espense for painting and water spray maintenance, or the third alternate of annual expense for painting and a higher insurance rate. Employing maximum coding in pressure vessel design reduces costs
In yeneial, pressure vessels should bc coded for the maximum temperature and pressure that can be obtained n-ith the wall thicknesses and flanges chosen for processing needs. For example, many pressure vessels are operated at atmospheric pressure or moderate pressures of 20 to 40 lb. (or even vacuum). These same vessels may be built from l/4- or 5/la-inch plate as a minimum thickness practice and are equipped with 150-lb. flanges. A check on the allowable working pressure on these vessels may reveal that they are good for 150 lb. or more, and even that the limiting pressure is set by the pressure rating of the flanges. In this case coding to match the 150-lb. flanges (say 150 lb. per sq. inch a t 500" F., or 130 lb. per sq. inch at 600" F.) or the highest pressure allowable for the wall thickness employed (say 100 lb. per square inch at 650" F.) should be employed. Such practice may greatly reduce the cost of the relief device required, and at the same time make this vessel much more usable (without recoding) for installation in other services when the plant may be revamped at a later date under expansion or process revisions. There are other fine points on the subject of designing reduced costs into the plant. The thoughts expressed, however, cover some of the more important methods by which a lower cost, and a t the same time a better constructed plant may be possible. Fortunately these features should also permit lower annual operating costs while providing that highly important feature of having a plant that should suffer a minimum of lost production through down time. Correspondence concerning this column will be forwarded if addressed to t h e author. e/o Editor, ISDUSTRIALA N D ENGIKEERINQ CHEMISTRY, 1155-16th St., N.W., Washington 6, D. C.
August 1955
Let's talk "LOW ABSORBENCY" For perchloric acid fume hoods. Alberene Stone has a low absorbency factor of 0.15%. It's essentially nonstaining. Easily cleaned. And readily machined for tongue and groove, watertight construction. Both of these features are absolutely essential for perchloric hoods - where thorough water flushing and removal is necessary to keep them deposit-free. Further, with Alberene Stone - the natural silicate stone whose surface goes all the way thru - the all-silicate mineral components resist chemical attack. Our engineers are ready to help you select or design perchloric hoods or other special-purpose hoods. Alberene Stone Corporation, 419 Fourth Avenue, New York 16, N. Y.
pvovides LOW ABSORBENCY protection For further information, circle number 93 A on Readers' Service Card, page 115 A
INDUSTRIAL AND ENGINEERING CHEMISTRY
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