Reaction, batch first-order

Daily Yield Say the downtime for filhng and emptying a reactor is and no reaction occurs during these periods. The reaction time of a first-order reaction, for instance, is given by = —In (1 — x). The daily yield with n batches per day will be... 

Figure 5-25B. For a first order reaction, the ratio of time in a continuous tank to the time in a batch tank for various percentages of reaction completion. By permission, Oidshue, J. Y. [29].

Determine the maximum batch reactor yield of B for a reversible, first-order reaction ... 

Example 5.5 Ingredients are quickly charged to a jacketed batch reactor at an initial temperature of 25°C. The jacket temperature is 80°C. A pseudo-first-order reaction occurs. Determine the reaction temperature and the fraction unreacted as a function of time. The following data are available ... 

The fed-batch scheme of Example 14.3 is one of many possible ways to start a CSTR. It is generally desired to begin continuous operation only when the vessel is full and when the concentration within the vessel has reached its steady-state value. This gives a bumpkss startup. The results of Example 14.3 show that a bumpless startup is possible for an isothermal, first-order reaction. Some reasoning will convince you that it is possible for any single, isothermal reaction. It is not generally possible for multiple reactions. 

Suppose there are two parallel, first-order reactions in a steady-state CSTR. Show that neither the fed-batch nor fast-fill-and-hold strategies can achieve a bumpless startup if the reactions have different rate... 

The alkylation of toluene with acetylene in the presence of sulphuric acid is carried out in a batch reactor. 6000 kg of toluene is charged in each batch, together with the required amount of sulphuric acid and the acetylene is fed continuously to the reactor under pressure. Under circumstances of intense agitation, it may be assumed that the liquid is always saturated with acetylene, and that the toluene is consumed in a simple pseudo first-order reaction with a rate constant of 0.0011 s-1. 

For a first-order reaction, the integrated form of the rate equation for a constant volume batch reactor, from Table 1.1 in Volume 3, is ... 

Two Reactions, Different Orders—In the case of a desired second-order reaction and an undesired first-order reaction, such as A + B - C and A — D, where C is the desired product, the batch, semi-batch, or plug-flow reactor is preferred. 

The first order reaction, A = 2.5B, is carried out in a batch reactor at 2 atm with 20% inerts present, and the volume increases by 60% in 20 min. In a constant volume reactor, find the time required to reach 8 atm if the initial pressure is 5 atm, 2 atm of which consists of inerts. 

A first order reaction takes place in batch, starting with Ca0 = 2 gmol/liter. The specific rate is represented by k = exp 21-7500/T) and the heat balance by T - 350 + 25(2-Ca)... 

A batch first order reaction is limited to a maximum of 600 K. Find the temperature profile that will give the maximum conversion- The rate equation is... 

Two consecutive, first-order reactions take place in a perfectly mixed, isothermal batch reactor. 

Jl An isothermal perfectly mixed batch reactor has consecutive first-order reactions... 

Integrate the Performance Equation. For a reversible first-order reaction, the performance equation for a batch reactor is... 

We want to produce R from A in a batch reactor with a run time no greater than 2 hours and at a temperature somewhere between 5 and 90°C. The kinetics of this liquid first-order reaction system is as follows ... 

These are terms to be introduced into the performance equation, Eq. 13. Also, further on in this chapter we will show that for first-order reactions, the macrofluid equation is identical to the batch or to the microfluid equation. 

For a first-order reaction in a batch, reactor Chapter 3 gives... 

An irreversible first-order reaction gave 95% conversion in a batch reactor in 20 min. 

The parallel first-order reactions A B. A C have activation energies of 8 and 10 kcal/mole, respectively. In a 1 liter batch reactor at 100°C the selectivity to B is 50% and the conversion is 50% in a reaction time of 10 min with Cao = 1 mole/liter. The solvent is water and the reactor can be pressurized as needed to maintain liquids at any temperature. 

Introductory textbooks in kinetics or chemical engineering describe how to determine the reaction order of a reaction from experimental data. Typically an assumption about reaction order is made, and this assumption is subsequently tested. Imagine that experimental data for the consumption of reactant A as function of time is available from experiments in a batch reactor. Initially we assume that A is consumed according to a first-order reaction,... 

In a first approximation a pseudo-first order reaction rate is often assumed. This must be checked against what really happens in the reactor. In semi-batch or nonsteady state oxidation, the concentration of the pollutants as well as the oxidants can change over time. A common scenario initially a fast reaction of ozone with the pollutants occurs, the reaction is probably mass transfer limited, the direct reaction in the liquid film dominates, and no dissolved ozone is present in the bulk liquid. As the concentration of the pollutants decreases, the reaction rate decreases, less ozone is consumed, leading to an increase in the dissolved ozone concentration. Metabolites less reactive with ozone are usually produced. This combined with an increase in dissolved ozone, may also shift the removal mechanism from the direct to the indirect if radical chain processes are initiated and promoted (see Chapter A 2). These changes are often not observed in waste water studies, mostly because dissolved ozone is often not measured. 

Table 1.3. Comparison of Continuous Stirred-Tank Reactors and Batch Reactors with Respect to Unit Output W k C0 and Reactor Volume. First-Order Reaction...

Fig. 1.22. Comparison of size and cost of continuous stirred-tank reactors with a batch or a tubular plug-flow reactor first-order reaction, conversion 0.9 ...

Fig. 1.25. Reaction in series—batch or tubular plug-flow reactor. Concentration Cr of intermediate product P for consecutive first order reactions, A -> P -> Q...

Fig. 1.28. Reactions in series—comparison between batch or tubular plug-flow reactor and a single continuous stirred-tank reactor. Consecutive first-order reactions,...

This preliminary study suggests that mass transfer models could describe many features of xylan hydrolysis with accuracy similar to that of conventional first-order reaction-only models that have been long used to describe such systems. For example, a simple leaching model can describe release of xylan into solution as the product of a concentration gradient times a mass transfer coefficient. This model predicts that flowthrough operation could improve xylan release compared to a batch system by reducing the concentration in solution and thereby increasing the concen-... 

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