Operating mode continuous

A second consideration is the operating mode continuous, batch, or semi-continuous. An extensive textbook on theory, design and scale-up of multiphase reactors was published by Gianetto and Silveston in 1986 [22], supplementing "Three-phase catalytic... 

Air classifiers may also be distinguished by method of powder feed. Particles may be fed either within air stream, or separately by freely pouring them within the device. Other systematizing may be done with respect to the air stream form, classifier design features and operation mode (continuous or batch). 

The influence of the operation mode continuous processes being simpler to optimize than batch processes... 

Most mass analyzers operate under high-vacuum conditions to ensure that charged particles do not deviate from their trajectories due to collision with residual gas. Mass spectrometers can be grouped into different types of operation mode continuous mode (magnetic sector, quadrupole), pulsed mode (time of flight), and ion trapping mode (quadrupole traps, Fourier transform ion cyclotron, orbitrap). 

Laser radiation can be produced in different operating modes (continuous, pulsed) and in different media (solid state, gas, dye). Pulse durations range from milliseconds to femtoseconds, as in nanosecond pulsed exdmer gas lasers which radiate in the deep ultraviolet (UV) (wavelength 157 to 351 nm) and femtosecond or millisecond pulsed solid state lasers (266 to 1070 nm). Continuous wave (cw) operation CO2 gas lasers radiate in the IR (10.6 pm). 

Manufacturing process and/or operation is continuous or semicontinuous, ie, at least one stage is in a continuous, as distinct from batch, mode. 

Given a sufficient number of stages and reflux, the vapor composition can be made to closely approach direct-mode, continuous operation in which the lowest-boiling species is taken overhead. As the... 

Drum and disc granulators generally operate in continuous feed mode. A key advantage to these systems is the abihty to run at large scale. Drums with diameters up to four meters and throughputs up to 100 ton/hr are widely used in the mineral industiy. 

When generators are specified, it should be realized that both mechanical and electrical requirements differ between units which will be used for standby service and units which will be operated continuously. Typically, standby units have less copper in their windings than continuous duty units, causing standby units to reach higher temperatures if operated continuously, and thus reducing life. Standby units, as classified by most manufacturers, are not to be confused with units which are alternated weekly (or on some other regular basis), but which are operated continuously when they are on line. This operating mode should be considered continuous duty. ... 

The number and severity of failures experienced by the equipment under study must be related to the operations of the facility. It would be inappropriate to assign the same operating histories to a continuously operating system and a system that operates intermittently. The number of hours in different operating modes (for example, 100% production versus shutdown) affect failure rate calculation and service description for taxonomy definition. 

The alternative to batch mode operation is continuous operation. In the continuous mode there is a continuous flow of medium into the fermentor and of product stream out of the fermentor. Continuous bioprocesses often use homogenously mixed whole cell suspensions. However, immobilised cell or enzyme processes generally operate in continuous plug flow reactors, without mixing (see Figure 2.1, packed-bed reactors). 

Modifying the mode of boiler operation to reduce boiler startups and wide load swings. Boilers are far less prone to silica vapors when operating at continuous load (provided, of course, that the basic pretreatment and water chemistry controls are in place). 

Multiphase reactors can be batch, fed-batch, or continuous. Most of the design equations derived in this chapter are general and apply to any of the operating modes. Unsteady operation of nominally continuous processes is treated in Chapter 14. 

In case of exothermic reactions, the heat-exchange capacities of the reactor allow to rapidly evacuate the heat generated by the reaction and therefore to perform a transposition of a pure batch operating mode into a continuous one. The main point is the ability to avoid, as far as possible, an initial increase of the temperature as soon as the reactants are mixed. 

As widely mentioned in the literature [29, 30], a batch operation with a constant temperature is, most of the time, a better operating mode than a fed batch, especially for selectivity reasons. Therefore, the transposition from a batch to a plug-flow continuous mode should be a promising operation if the operating temperature is strictly controlled. 

X-ray Diffraction. Eliffiactograms were obtained with a ShiimdzuXD-Dl instrament with monochromator using CuKa, radiation. It was operated in continuous scan mode at 0.5° (20) min. ... 

Both batch and continuous adsorption processes are used. In a batch process, the adsorbent bed is allowed to become saturated with adsorbed material and is subsequently regenerated in a cyclic manner. In a continuous process, usually the counter-current mode is adopted for adsorption and desorption, either in time form or in simulated mode. Continuous operation offers many advantages with respect to the efficiency of adsorbent utilization. Thus, for... 

Batchwise operating three-phase reactors are frequently used in the production of fine and specialty chemicals, such as ingredients in drags, perfumes and alimentary products. Large-scale chemical industry, on the other hand, is often used with continuous reactors. As we developed a parallel screening system for catalytic three-phase processes, the first decision concerned the operation mode batchwise or continuous. We decided for a continuous reactor system. Batchwise operated parallel sluny reactors are conunercially available, but it is in many cases difficult to reveal catalyst deactivation from batch experiments. In addition, investigation of the effect of catalyst particle size on the overall activity and product distribution is easier in a continuous device. 

Xylene isomerization reactions can be accomplished by contacting a hot gas stream with a solid catalyst. Under these conditions the isomerization reactions may be regarded as reversible and first-order. Unfortunately, the catalyst also catalyzes disproportionation reactions. These reactions may be regarded as essentially second-order and irreversible. If one desires to achieve an equilibrium mixture of isomers with minimal material losses due to disproportionation, what do you recommend concerning the mode in which one should operate a continuous flow reactor ... 

New applications and novel reactor configurations or operational modes for three-phase systems are continually being reported. These include the operation of a three-phase fluidized bed in a circulatory mode (Liang et al., 1995), similar to the commonly applied gas-solid circulating fluidized bed the application of a three-phase fluidized bed electrode that can be used as a fuel cell (Tanaka et al., 1990) magnetically stabilized three-phase fluidized beds centrifugal three-phase reactors and airlift reactors. 

CO oxidation over Pd/y-Al203 and Pt/y-Al203 [94, 95], Reaction conditions single-mode packed bed microwave reactor operated on continuous basis at 915 MHz. 

All these problems could be convincingly overcome by application of the continuous operation mode [63 d)]. Most interestingly, this unusual continuous biphasic reaction mode enabled the quantitative separation of relatively high boiling products from the ionic catalyst solution under mild temperature conditions and without use of an additional organic extraction solvent. More details of this process are included in Chapter 8, Section 8.2.2.3. 

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