Design and operation

The performance of adsorptive (and indeed almost all multifunctional) reactors benefits from an expedient nonuniform distribution and integration of the functionalities at various levels. Simply combining given proportions of catalyst and adsorbent in a fixed-bed reactor seldom realizes the full potential available [52]. The objective may be to maximize utilization of adsorbent capacity or to optimize catalyst productivity. Although these aims need not be mutually exclusive, they often give rise to different strategies. 

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Bonnell D A 1993 Microscope design and operation Scanning Tunnelling Microscopy and Spectroscopy ed D A Bonnell (Weinheim VCH) ch 2... 

The design and operation of a flow visualization system for highly viscous fluids, such as silicon rubber, has been reported by Ghafouri and Freakley (1994). This system consists mainly of a rotating roll and fixed-blade assembly, as is shown in Figure 5.7, and can be used to generate and maintain, essentially. 

Our primary objective in this section is the discussion of practical osmometry, particularly with the goal of determining the molecular weight of a polymeric solute. We shall be concerned, therefore, with the design and operation of osmometers, with the question of units, and with circumventing the problem of nonideality. The key to these points is contained in the last section, but the details deserve additional comment. 

J. Huegenin and J. Colt, Design and Operating Guide forMquaculture Seawater Systems Elsevier, New York, 1989. 

This second reaction leads to the small amount of branching (usually less than 5%) observed in the alcohol product. The alpha olefins produced by the first reaction represent a loss unless recovered (8). Additionally, ethylene polymerisation during chain growth creates significant fouling problems which must be addressed in the design and operation of commercial production faciUties (9). 

Table 9. Design and Operating Characteristics of Glanor Bipolar Diaphragm Electrolyzers...

Extraction, a unit operation, is a complex and rapidly developing subject area (1,2). The chemistry of extraction and extractants has been comprehensively described (3,4). The main advantage of solvent extraction as an industrial process Hes in its versatiHty because of the enormous potential choice of solvents and extractants. The industrial appHcation of solvent extraction, including equipment design and operation, is a subject in itself (5). The fundamentals and technology of metal extraction processes have been described (6,7), as has the role of solvent extraction in relation to the overall development and feasibiHty of processes (8). The control of extraction columns has also been discussed (9). 

Special safety constraints apply to equipment selection, design, and operation in nuclear reprocessing (269). Equipment should be reHable and capable of remote control and operation for long periods with minimal maintenance. Pulsed columns and remotely operated mixer—settlers are commonly used (270). The control of criticaHty and extensive monitoring of contamination levels must be included in the process design. 

This article is intended to provide a useful first understanding of flow phenomena and techniques and to provide an entry to more precise and detailed methods where these are required. Although the main concern is the proper design and operation of plant equipment, the importance of preservation of the environment is recognized. Thus data from the fields of meteorology and oceanography are occasionally needed by the technologist (see also Flowl asurel nt Fluidization). 

E. R. Schulman, W. G. BurweU, and R. A. Meinzer, "Design and Operation of Medium Power CWHE/DE Chemical Lasers," ML4M 7th Fluid and Plasma Dynamics Conference, Palo Alto, Calif., AlAA Paper No. 74-546, June 1974. 

W. Trinks and M. Mawhinney, Industrial Furnaces, Principles of Design and Operation, 5th ed., Vol. 1, John Wiley Sons, Inc., New York, 1961, 486 pp. 

M. Bashar and T. S. C2amecki, "Design and Operation of a Lignite-Fired CFB Boiler Plant," Proceedings of the Tenth International Conference on Fluidi d Bed Combustion, San Francisco, May 1—4,1989. 

E. J. Gottung and S. J. Sopko, "Design and Operation of a CEB Steam Generator Firing Anthracite Waste," presented at the 1988Joint AS ME/IEEE Power Generation Conference, Philadelphia, Sept. 25—28,1988. 

Natural gas is attractive as a fuel ia many appHcatioas because of its relatively clean burning characteristics and low air pollution (qv) potential compared to other fossil fuels. Combustion of natural gas iavolves mixing with air or oxygen and igniting the mixture. The overall combustion process does not iavolve particulate combustion or the vaporization of Hquid droplets. With proper burner design and operation, the combustion of natural gas is essentially complete. No unbumed hydrocarbon or carbon monoxide is present ia the products of combustioa. 

The principal class of reactions in the FCC process converts high boiling, low octane normal paraffins to lower boiling, higher octane olefins, naphthenes (cycloparaffins), and aromatics. FCC naphtha is almost always fractionated into two or three streams. Typical properties are shown in Table 5. Properties of specific streams depend on the catalyst, design and operating conditions of the unit, and the cmde properties. 

Dowtherm Heat-Transfer Fluids. Dow Chemical Co. manufactures a family of heat-transfer fluids to meet differing appHcations. Dow Chemical also markets the Syltherm fluids produced by Dow-Coming Corp. Design and operating guidelines are offered in many of the company pubHcations describing the Dowtherm fluids. 

Design and Operational Considerationsfor High Temperature OrganicHeat Transfer Systems, Dow Chemical Co., Midland, Mich. 

Other above-ground continuous flow systems have been designed and operated for SCWO processes. A system developed by ModeU Development Corp. (Modec) uses a tubular reactor and can be operated at temperatures above 500°C. It employs a pressure letdown system in which soHd, Hquids, and gases are separated prior to pressure release. This simplifies valve design and material selection on the Hquid leg. 

LPG recovered from natural gas is essentially free of unsaturated hydrocarbons, such as propylene and butylenes (qv). Varying quantities of these olefins may be found in refinery production, and the concentrations are a function of the refinery s process design and operation. Much of the propylene and butylene are removed in the refinery to provide raw materials for plastic and mbber production and to produce high octane gasoline components. 

The selection of a particular type of reduction depends on technical feasibiUty and the economics of the process as well as on physicochemical considerations. In particular, the reducing agent should be inexpensive relative to the value of the metal to be reduced. The product of the reaction, RX, should be easily separated from the metal, easily contained, and safely recycled or disposed of. Furthermore, the physical conditions for the reaction should be such that a suitable reactor can be designed and operated economically. 

A homogenize is a high pressure positive pump with three, five, or seven pistons, that is driven by a motor and equipped with an adjustable homogenizing valve. Smoother flow and greater capacity are obtained with more pistons, which force the product iato a chamber that feeds the valve. In design and operation, it is desirable to minimize the power requirements for obtaining an acceptable level of homogenization. At 17.2 MPa (2500 psi) and a volume of 0.91 t/h (2000 lb/h), a 56-kW (75-hp) motor is required. 

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