Calculate the jacket heat-transfer rate, Qj, from Equations 7.4.7 to 7.4.9 and [Pg.385]

J-acid, 9 402, 403 Jackets, heat-transfer, 16 111—718 Jacobsen s ligand, 20 305 Jacobson-Stockmayer theory, in siloxane polymer manufacture, 22 558 Jacquinot advantage, 14 228 J-aggregation, 9 508 Jahn-Teller distortion, 22 203 Jahn—Teller effect, 6 611 Jai Tire process, 21 476 Jameson cell, 16 653 Jamming phase diagram, 12 18 Jams [Pg.499]

Effect of Reactor Type, Jacket Heat Transfer Fluid, and Reactor Fluid Viscosity [Pg.139]

A simplified schematic for a jacket heat transfer service is shown in Figure 11 [18]. Here, two separate heat transfer fluid headers are used, and the control valve is on the outlet stream to reduce the temperature shocks that might occur if a single [Pg.154]

Starting up a jacketed batch reactor requires control of the heat-up and cool-down rates. To do this, the jacket heat-transfer-fluid temperatures have to be determined and set. This can be done by trial-and-error experiments, but it is often quicker and more straightforward to simply make a trial heat-up and then plug the results into time-dependent heat-transfer equations. Here s how to do this for steam or hot-water jacketed reactors. [Pg.57]

In all the simulations up to now the jacket volume has been calculated by using the jacket heat transfer area and assuming a jacket thickness of 0.1 m. The jacket volume has no [Pg.121]

Zakrzewska and Jaworski [101] performed single phase CFD simulations of turbulent jacket heat transfer in a Rushton turbine stirred vessel using the eight turbulence models mentioned above as implemented in FLUENT. In all simulations the boundary flow at the vessel wall was described by the [Pg.745]

Buildup can occur either rapidly during an unstable batch or slowly over many normal batches. Buildup drastically reduces jacket heat transfer, slowing heatup and cooldown and, if serious [Pg.89]

We demonstrate in this section that the besf temperature from the standpoint of controllability is not the highest possible. This results from the reduction in cooling-jacket heat transfer area that occurs as the size of the reactor is reduced. The temperature difference between the reactor and the jacket becomes bigger, resulting in a reactor that is more difficult to control. [Pg.165]

The kinetics used are those given in Chapter 2 (Table 2.2). The desired operating temperature is 340 K. The diameter of the reactor is 2 m, giving a total volume of 12.57 m3 and jacket heat transfer area of 25.13 m2. The reactor is initially charged with 6.285 m3 of pure B with a composition CB = 8.01 kmol/m3. The initial reactor temperature is 300 K. [Pg.211]

The first reactor in the 3-CSTR process has a conversion rate of 72.8%, and the reactant concentration in this first reactor is 2.18 kmol/m3. The reactor volume is low (14.3 m3), and the jacket heat transfer area is only 24.5 m2. The resulting jacket temperature (300 K) is almost down to the inlet cooling water temperature of 294 K. Linear analysis gives a Nyquist plot that never drops into the third quadrant, so the critical (—1,0) point cannot be encircled in a counterclockwise direction. This is required for closedloop stability because the openloop system is unstable and has a positive pole. Thus a proportional controller cannot stabilize this first reactor. [Pg.131]

The ethylbenzene CSTR considered in Chapter 2 (Section 2.8) is used in this section as an example to illustrate how dynamic controllability can be studied using Aspen Dynamics. In the numerical example the 100-m3 reactor operates at 430 K with two feedstreams 0.2 kmol/s of ethylene and 0.4 kmol/s of benzene. The vessel is jacket-cooled with a jacket heat transfer area of 100.5 m2 and a heat transfer rate of 13.46 x 106 W. As we will see in the discussion below, the steady-state simulator Aspen Plus does not consider heat transfer area or heat transfer coefficients, but simply calculates a required UA given the type of heat removal specified. [Pg.162]

© 2019 chempedia.info