Designing for Efficiency

Proper cleaning of an air-cooler tube requires removing two plugs. A large industrial air cooler may have 2000 tubes or 4000 plugs. The labor involved to remove and reinstall all these plugs is formidable. 

Leaking plugs due to cross-threading is a common start-up problem. Hence, many air coolers are simply never cleaned. 

The pass partition baffle shown in Fig. 19.5 makes this cooler a two-pass exchanger. These baffles are subject to failure due to corrosion. More often, they break because of excessive tube-side pressure drop. The differential pressure across a two-pass pass partition baffle equals the tube-side AP. 

Once the pass partition baffle fails, the process fluid may bypass the finned tubes, and cooling efficiency is greatly reduced. This is bad. But worse yet, during a turnaround of the cooler, there is normally no way to inspect the pass partition baffle. There is no easy way to visually verify the mechanical integrity of this baffle. A few air coolers have removable inspection ports for this purpose most do not. 

If one of the air coolers begins to experience tube-side fouling, the fluid flow will be reduced. But the tube-side pressure drop will remain 

Individual flows to parallel banks of air coolers are rarely— if ever—measured. Regardless, we can gauge the approximate relative flow to each bundle. This can be done by checking the outlet temperature 

Let s assume that the cooling airflow to all five banks is the same. Banks A and B in Fig. 17.6 have low outlet temperatures. Banks C, D, and E have much hotter outlets. Question Which coolers are handling most of the heat-transfer duty Is it A and B or C, D, and E  

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Q-Chem (we tested Version 1.2) is an ah intio program designed for efficient calculations on large molecules. Q-Chem uses ASCII input and output files. 

Exothermicity. The catalytic reactions are often exothermic bond-forming reactions of small molecules that give larger molecules. Consequendy, the reactors are designed for efficient heat removal. They may be jacketed or contain coils for heat-transfer media, or the heat of reaction may be used to vaporize the products and aid in the downstream separation by distillation. 

The bubble cap has been studied extensively and several design recommendations have been presented over the years. The most complete and generally applicable is that of Bolles [5]. It should be stressed that proper mechanical interpretation of process requirements is essential in design for efficient and economic operation. There is not just one result, but a multiplicity of results, each unique to a particular set of conditions, and some more economical than others. Yet at the same time, many of the mechanical design and fabrication features can be identical for these various designs. 

Planning and building a laboratory requires a cooperative effort involving administrators, designers, equipment supply houses, contractors, and the laboratory operator. A laboratory designed for efficient operation can be achieved only if all of them work together with mutual respect and the best possible communication. 

Since 1946, when it was first proposed that the spontaneous emission from an excited state of an emitter can be significantly altered if it is placed into low-loss wavelength-scale cavity (Purcell, 1946), various microresonator designs for efficient control of spontaneous emission have been explored... 

B. Agate, B. Stormont, A.J. Kemp, C.T.A. Brown, U. Keller, and W. Sibbett, Simplified cavity designs for efficient and compact femtosecond Cr LiSAF lasers. Optics Communications 205,207-213 (2002). 

Zeng AZ (2003) Global sourcing process and design for efficient management. Supply Chain Management An International Journal 8 367-379... 

The economic competition that comes from the global economy will produce changes in the process industries and plant design. Improved energy efficiency will be important in chemical processing. Fuel price fluctuations pass directly to the product costs are so designed for efficient energy use. 

Zheng, H. Keith, J.M. A new design for efficient diesel particulate trap regeneration. AIChE J. 2004, 50, 184-191. 

Sikorski, R. S. and Hieter, P. 1989. A system of shuttle vectors and yeast host strains designed for efficient manipulation of DNA in Saccharomyces cerevisiae. Genetics, 122, 19-27. 

Desilvestro, J., S. Pons, E. Vrachnou, M. Gratzel (1988), Electrochemical and FTIR Spectroscopic Characterization of Ferrocyanide-Modified Ti02 Electrodes Designed for Efficient Photosensitization, J. Electroanal. Chem. 246, 411-422. 

This part provides the I.O.N.S. guidelines for the memos that individuals who perform the work will write to the clients. The word memo is short for memorandum. In general, a memo is meant to be a brief and to-the-point written document that reports information and/or recommends action. Memos are designed for efficient distribution and easy, quick reading. For I.O.N.S., this means that we will report our results to our clients in as efficient a manner as possible. It will be a brief, to-the-point presentation for easy, quick reading. Our major objective with the report memo is the satisfaction of our customers. Such is the task of analytical scientists throughout the industry, as conveyed in the quotation in Figure 2.6, and is certainly the task of analytical scientists in the I.O.N.S. Corporation. 

If an absorber is to be designed for efficient and economical service, the solvent chosen must have a special affinity for the one or more components of the gas mixture that are to be selectively removed. In other words, a degree of solubility is needed. Solubility data, which relate the solute, the solvent, the concentrations, and the temperature-pressure conditions, may be found in various compendia and journal articles. In the past, it was common to report solubility as a Bunsen solubility coefficient ... 

Particularly in the pharmaceutical industry, cleaning requirements may necessitate installation of the chopper(s) through a removable roof as shown in Fig. 7.45b. This apparatus is designed for efficient mixing, granulating, gas stripping, and vacuum drying in a one-pot manner. To avoid condensation the so called auto-lift lid is also heated in this case. 

Gl, G2, G2(MP2), and G3 are composite computations using the 6-311G basis set and MP2/6-31G geometry optimization. The protocols are designed for efficient calculation of energies and electronic properties. The G2 method calculates electron correlation at the MP4 level, while G2(MP2) correlation calculations are at the MP2 level. A scaling factor derived from a series of calibration molecules is applied to energies. 

Kohori F, Yokoyama M, Sakai K, Okano T. Process design for efficient and controlled drug incorporation into polymeric micelle carrier systems. J Contr Rel 2002 78 155-163. 

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