Residence time, determination

Kersten M, Thomsen S, Priebsch W, Garbe-Schonberg CD (1998) Scavenging and particle residence times determined from Th-234/U-238 disequilibria in the coastal waters of Mecklenburg Bay. Appl Geochem 13 339-347... 

Poet, S. E., H. E. Moore and E. A. Martell, Lead-210, Bi-210, and Polonium-210 in the Atmosphere Accurate Ratio and Application to Aerosol Residence Time Determination, J. Geophys. Res.,... 

The most interesting process is, therefore, the flash pyrolysis, because it leads to the maximum yield of the most valuable product, the oil. For this process, the key parameters are the char separation and the vapor residence time (determined by the quenching method). 

The separation residence time determines the relationship between separator size and separator throughput. Extensive property determinations were made during prior development and testing of candidate CSSX solvent formulations [49],... 

Figure 5 Residence time determination using particle trajectory (Wong and Seville, 2006).

Severity of the operation, according to the kinetic equation expressing the KSF. Residence time, determined from the mass flow rate of the reaction mixture and its average specific weight in the tube ... 

THE RESIDENCE TIME DETERMINES RISER HEIGHT AND RECYCLE RA TIO... 

The objective of sca)ing-up a vacuum pyrolysis reactor is to achieve the desired capacity and conversion of feedstock by defermining the dimension of the reactor. The feedstock conversion in a vacuum pyrolysis reactor mainly depends on three factors the heat transfer coefficient from the reactor to the feedstock the residence time of the feedstock in the reactor and the kinetics of the feedstock pyrolysis reactions. The heat transfer coefficient and the residence time determine the quantity of energy transferred and thus the temperature distribution throughout the feedstock in the reactor. The tert erature distribution and the kinetics determine the final conversion achieved at the reactor outlet. 

The decrease in enzyme activity in a continuous reactor causes a decreasing conversion of the substrate. Only in the case of low conversion (compare to initial reaction rate , see Sect. 7.4.1), the decrease of enzyme activity is proportional to the decrease of conversion and may be calculated from these data. Alternatively, the remaining activity in the reactor may be measured by taking samples of the enzyme (especially when using membrane reactors) or by adding fresh enzyme, until the initial conversion is re-established. In stirred tank reactors, the product of enzyme activity and residence time determines the conversion (see Sect. 7.5.1). Therefore,... 

The RTD allows to calculate t, the residence time of the material in the device. If T is the mean residence time, determined by ... 

Global kinetics, however, allowed calculation of some parameters in normal volunteers, i.e., fractional catabolic rate, rate of synthesis, and mean residence time determined by the mathematical analysis of both plasma decay curves and urinary excretion rates. Such studies demonstrated different metaboUsms for Apo C-I, C-II, and C-III. They may supply essential information on the perturbations observed in pathology. 

The reaction diagram for a single component reaction, as shown in Fig. 7.2 has two adjustable parameters, the amount of initiator and therefore the radical concentration and the temperature, all other parameters depend on changes in these two primary variables (2). Due to the deeomposition kinetics, the radical concentration depends of course also on the temperature of the reacting mixture. In reactive extrusion this temperature is affected by the wall temperature and the heat transfer coefficient but also by the reaction velocity, which, in turn, is influenced by the radical concentration and the temperature. The reaction velocity, together with the residence time determines the conversion, which has its effect on the viscosity of the reacting mixture. The viscosity is also affected by the average... 

Poet, S.E., Moore, H.E., Martell, E.A. (1972). Lead-210, bismuth-210 and polonium-210 in the atmosphere Accurate ratio measurement and application to aerosol residence time determination. J. Geophys. Res. 77 (33), 6515-6527. 

Thermal NO, is generally regarded as being generated by a chemical reaction sequence called the Zeldovich mechanism. This set of well-verified chemical reactions postulates that the rate of generation of thermal NO, is an exponential function of the temperature of the flame. It, therefore, follows that the amount of NO, generated is a function not only of the temperature but also of the time the hot gas mixture is at flame temperature. It turns out to be a linear function of time. Thus, temperature and residence time determine NO, emission levels and are the principal variables that a gas turbine designer can alter to control emission levels. 

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