Minimum feed temperature

Toy and for any prescribed Tfy the unknown Tq can be read off. Figure 9.18 shows the results of Baddoufs calculations on the standard case and it is at once evident that for Tf between 224 C and 27O C there can be two values of Tq. The smaller of these is unstable because the slope of the curve is negative here and an increase in Tf actually decreases Tq, The minimum feed temperature of 224 C is called the blow-out feed temperature for there is no intersection on the figure at all. Actually, the curve goes out of the figure to the left and quickly drops to the asymptote To = Tf this means that there is virtually no reaction taking place since the feed is too cold. Stable operation which is also profitable is to be found only on the part of the curse to... 

List reaction constraints minimum feed temperature, maximum temperature and pressure, as well as safety aspects. 

Experience in air separation plant operations and other ciyogenic processing plants has shown that local freeze-out of impurities such as carbon dioxide can occur at concentrations well below the solubihty limit. For this reason, the carbon dioxide content of the feed gas sub-jec t to the minimum operating temperature is usually kept below 50 ppm. The amine process and the molecular sieve adsorption process are the most widely used methods for carbon dioxide removal. The amine process involves adsorption of the impurity by a lean aqueous organic amine solution. With sufficient amine recirculation rate, the carbon dioxide in the treated gas can be reduced to less than 25 ppm. Oxygen is removed by a catalytic reaction with hydrogen to form water. 

For the minimum volume in a CFSTR under adiabatie eondition, Equation 6-192 requires only that the operating temperature within the reaetor be T p. In this ease, there is nothing about the mode of operation, sueh as the feed temperature Tg or heat transfer, either within the reaetor or upstream of it. However, if the CFSTR is operated adiabatieally for speeified eonversion (X ) and molar flowrate (F q = uC o) without internal heat transfer, Tq must be adjusted to a value obtained from the energy balanee as determined by... 

Heat energy can be saved by using the hot bottom product to preheat the feed in an economizer (Figure 2.89c). In order to maximize the amount of heat recovered, a VPC is used as the cascade master of the feed temperature controller. The goal of optimization is to keep the bypassed flow at a minimum. Therefore, the VPC is usually set at about 10% of the valve opening. 

Flush the membranes. Membranes should be flushed following cleaning using RO-permeate quality or better water. Pretreated feed water should not be used as components may interact with the cleaning solution and precipitation of foulants my occur in the membrane modules. The minimum flush temperature should be 20°C. ... 

Propane gas and air are to be mixed and fed to a combustion reactor. The combustion is to be initiated with a gas torch. Determine the minimum and maximum percentages of propane in the feed to the reactor and the minimum required temperature of the torch flame. 

One feasible network would correspond to the cold streams Cl, C8, and C9 diverted to suitable jacketed reactor compartments, as the simple network in Fig. 14 shows. The hot streams not shown in this network are matched directly with cooling water (CW), and the amount of steam used here is very small. Note that this network would require the same minimum utility consumption predicted by the solution of (PIO). It can be inferred that the network in Fig. 14 is equally suitable for both the simultaneous and sequential solutions. In fact, Balakrishna and Biegler (1993) showed that, for exothermic systems in which the reactor temperature is the highest process temperature, the pinch point is known a priori as the highest reactor temperature (in this case, the feed temperature) and the inequality constraints in (PIO), Qh 2h () ). F G P. can be replaced by a simple energy balance constraint. This greatly reduces the computational effort to solve (PIO). 

The low temperature range affecting arthropods could perhaps be divided into three bands. From the minimum breeding temperature down to the chill coma, insects will be able to feed, but because of their low metabolic rate, be unable to repair accumulating damage. From the chill coma temperature down to the supercooling point, they will be unable to feed and therefore slowly starve. At and below their supercooling temperature, death will occur when the water in their body fluids crystallises (freezes). 

NUMBER OF IDEAL PLATES AT OPERATING REFLUX. Although the precise calculation of the number of plates in multicomponent distillation is best accomplished by computer, a simple empirical method due to Gilliland is much used for preliminary estimates. The correlation requires knowledge only of the minimum number of plates at total reflux and the minimum reflux ratio. The correlation is given in Fig. 19,5 and is self-explanatory. An alternate method devised by Erbar and Maddox is especially useful when the feed temperature is between the bubble point and dew point. 

Maximum temperature of feed in evaporative crystallizer Minimum operating temperature in evaporative crystallizer Maximum evaporation rate based on heat transfer area or liquid droplet entrainment limitation Maximum residence time at design capacity... 

For a multistage reactor, there is an optimum feed temperature for each stage, but the intermediate conversions are also variables to be optimized. For a three-stage converter with a fixed total conversion, there are three feed temperatures and two intermediate conversions to be optimized to get the minimum amount of catalyst. 

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