Simulation reactor

Figure 8.1.3 Results of reactor simulation with true kinetics (with pressure drop).

Figure 9.7.2 Plug-flow reactor simulation. Inside temperature vs. Tube length at various tube wall temperatures, in K ...

Figure 9.7.4 Plug-flow reactor simulation at Twaii=485.4K.

Yields from a Continuous Backmix Reactor, Simulated with C0NGAS... 

The vertical reactor simulations reported In this paper typically Involved 14,000 unknowns and took 25 CPU seconds per Newton Iteration on a Cray-2. The tracing of a complete family of solutions for one parameter (e.g. susceptor temperature) cost approximately 25 CPU minutes. The latter number underscores the advantage of using supercomputers to understand the structure of the solution space for physical problems which often Involve many parameters. 

The large scale reactor simulations represent a step towards realistic... 

Increased computational resources allow the widespread application of fundamental kinetic models. Relumped single-event microkinetics constitute a subtle methodology matching present day s analytical techniques with the computational resources. The singleevent kinetic parameters are feedstock invariant. Current efforts are aimed at mapping catal) t properties such as acidity and shape selectivity. The use of fundamental kinetic models increases the reliability of extrapolations from laboratory or pilot plant data to industrial reactor simulation. 

Eulerian two-fluid model coupled with dispersed itequations was applied to predict gas-liquid two-phase flow in cyclohexane oxidation airlift loop reactor. Simulation results have presented typical hydrodynamic characteristics, distribution of liquid velocity and gas hold-up in the riser and downcomer were presented. The draft-tube geometry not only affects the magnitude of liquid superficial velocity and gas hold-up, but also the detailed liquid velocity and gas hold-up distribution in the reactor, the final construction of the reactor lies on the industrial technical requirement. The investigation indicates that CFD of airlift reactors can be used to model, design and scale up airlift loop reactors efficiently. 

Reactor Simulation for an Up-flow Anaerobic Sludge Blanket Process... 

In the following, tiie performance of a UASB reactor with the same size of a pilot plant [7] is evaluated according to the reactor simulation model incorporated with the Monod kinetic paramet for fire hypothetical influait coirqxwiticHi for the three VFA componaits as indicated in Table 2. 

The component mass balance, when coupled with the heat balance equation and temperature dependence of the kinetic rate coefficient, via the Arrhenius relation, provide the dynamic model for the system. Batch reactor simulation examples are provided by BATCHD, COMPREAC, BATCOM, CASTOR, HYDROL and RELUY. 

Luyben (1973) (see simulation example RELUY) also demonstrates a reactor simulation including the separate effects of the measuring element, measurement transmitter, pneumatic controller and valve characteristics which may in some circumstances be preferable to the use of an overall controller gain term. 

A valid mechanistic model can be very useful, not only in that it can appreciably add to our process understanding, but also in that it can be successfully employed in many aspects of emulsion polymerization reactor technology, ranging from latex reactor simulation to on-line state estimation and control. A general model framework has been presented and then it was shown how it can be applied in a few of these areas. The model, being very flexible and readily expandable, was further extended to cover several monomer and comonomer systems, in an effort to illustrate some of its capabilities. 

For a more detailed analysis of measured transport restrictions and reaction kinetics, a more complex reactor simulation tool developed at Haldor Topsoe was used. The model used for sulphuric acid catalyst assumes plug flow and integrates differential mass and heat balances through the reactor length [16], The bulk effectiveness factor for the catalyst pellets is determined by solution of differential equations for catalytic reaction coupled with mass and heat transport through the porous catalyst pellet and with a film model for external transport restrictions. The model was used both for optimization of particle size and development of intrinsic rate expressions. Even more complex models including radial profiles or dynamic terms may also be used when appropriate. 

All companies have conducted considerable research and development on these processes, and they have also developed reactor simulation programs to predict the behavior of these complicated plants. The low cost producer will be the company that has the most efficient process. This requires optimizing the reactor, and this in turn requires understanding the reactions and their engineering. 

Repeat the reactor simulation, but with an inlet gas stream consisting of 0.33 Torr of SiH4,10 Torr of H2, and 189.7 Torr of He. What is the maximum number density of Si in this simulation Give a qualitative, chemical explanation for the change from the pure He calculation in task 1. 

D.A. Hickman and L.D. Schmidt. Steps in CH4 Oxidation on Pt and Rh Surfaces High-Temperature Reactor Simulation. AIChE7., 39 1164-1177,1993. 

Several operating conditions have been found which satisfy the requirements for no coke formation. The optimum S/C ratio at 3.5 appears to fulfill the requirements for temperatures around 800°C for steam reforming process. The optimum O/C and S/C ratios are found 0.45 and 1.5 respectively for ATR reactor simulations at the inlet temperature of 700°C. 

Software tools are applied in every step of process development. Tools for individual reactor simulations such as computational fluid dynamic simulations are not the topic in this chapter. These tools supply only numerical data for specific defined reactor geometry and defined specific process conditions. A change of parameter would demand a complete recalculation, which is often a very time-consuming process and not applicable to a parameter screening. Methods for reactor optimization by CFD are described in detail in the first volume of this series. Tools for process simulation allow the early selection of feasible process routes from a large... 

Figure 3.45 Matlab program for autorefrigerated reactor simulation.

Figure 4.2 Matlab program for batch reactor simulation.

TUBULAR REACTOR SIMULATION USING ASPEN PLUS 277... 

Figures 7.13 and 7.14 give results using the FS2 flowsheet with the furnace for this hot-reaction case. Figure 7.13 shows that a 10% decrease in recycle flowrate can be handled, but a 20% decrease produces a reactor mnaway. This occurs despite the fact that the reactor inlet temperature increases only slightly ( 0.5 K) during the transient. Figure 7.14 gives results for changes in the setpoint of the reactor inlet temperature controller. Rather surprisingly, inlet temperature can be increased by 2 K without a runaway. This is unexpected since the isolated reactor (Fig. 7.12) showed a runaway with a +2 K change in Tm. The difference may be due to the effect of pressure. In the isolated reactor simulation, pressure is held constant at 50 bar. In the simulation of the whole process, pressure drops as reactor temperature increases due to the increased consumption of reactants. Since the reaction rate depends on the square of the total pressure (P2), the decrease in pressure lowers the reaction rates. However, a 3 K increase cannot be handled.

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