Minimum reactor volume

Minimum reactor volumes of isothermal and nonisothermal cascades by dynamic programming... 

MINIMUM REACTOR VOLUME AT THE OTP OF A SINGLE CFSTR WITH A REVERSIBLE EXOTHERMIC REACTION ... 

Consider the reversible first order reaction A R. It is possible to determine the minimum reactor volume at the optimum temperature Tgp( that is required to obtain a fractional conversion X, if the feed is pure A with a volumetric flowrate of u. A material balance for a CESTR is... 

Determine the minimum reactor volume that will be required to obtain a fraction conversion fc if the feed is pure C and if the input volumetric flow rate is What will be the temperature of the effluent stream ... 

The reactor would be run adiabatically, but the maximum reaction temperature allowable is 400 °C, since above this temperature undesirable by-products are formed. Calculate the minimum reactor volume required to obtain 80% conversion of A. What must the heat transfer rate be in the cooling section of the reactor ... 

For the reaction in problem 14-13, determine the minimum reactor volume required for a two-stage CSTR used to achieve 65% conversion of A. What is the volume of each tank ... 

A second-order reaction of A - B, with fcA = 2.4 L mol 1 h 1, is to be conducted in up to two CSTRs arranged in series. Determine the minimum reactor volume required to achieve 66.7% conversion of A, given that the feed rate and volumetric flow rate at the inlet are 3.75 mol min 1 and 2.5 L min 1, respectively. The feed consists of pure A... 

If we assume the density of the HMT solution to be 72 Ib/ft, the minimum reactor volume is 50 ft. A cylindrical vessel 4 ft in diameter and 6 ft in height would provide 33% excess capacity. If the 1-in. tubing were wound into a 3-ft-diameter coil, approximately 12 loops would be needed. 

Therefore, a systemic approach is necessary in designing chemical reactors. In this chapter, we will demonstrate that a minimum reactor volume is required in a recycle system for flexible operation. Moreover, the nominal design should be placed sufficiently far away from the maximum sensitivity region of the relation conversion-reactor volume. It is worthy to note that multiple steady states are possible in the case of several recycles of reactants. The recycle of heat gives an even more complicated behaviour. Moreover, the stability and performance of the reactor system depends also on the control structures of other units. Hence, reactor design and feasibility of the control structures at the plant level should be examined simultaneously. 

A comparison of reactor volumes for all four cases considered shows that a combination of an MFR and a PFR in series gives the minimum reactor volume. However, economic considerations may point to a single recycle reactor as the best alternative. 

This chapter aims to provide several worked examples of how to generate candidate ARs. All of these examples are two-dimensional in nature, which is useful for demonstration purposes because the results are easily visualized. Do not let this constraint mislead you into thinking that the examples are insignificant. By the end of this chapter, readers should be able to solve reactor network problems with multiple reactions involving selectivity, yield, conversion, and minimum reactor volume. 

Hence, let us develop a suitable objective function that incorporates the required produet eoneentration and minimum reactor volume, which may be used in profitability calculations for the plant. Usefiil information for this example is given as follows ... 

Constructions involving minimum residence time (minimum reactor volume) were also discussed. These constructions are effectively identical to those constructed in concentration space (the phase plane). This is feasible as residence time behaves as a pseudo component in concentration space—r obeys a linear mixing law and it is easily incorporated into the rate vector r(C). 

A number of small examples, centered on the optimization of exothermic adiabatic reactions, were also covered. These types of reactions are commonly found in industry. We find that operating procedures such as interstage and cold-shot cooling are appropriate for minimum reactor volume problems, and may be validated by viewing the problem from an AR perspective. These discussions also demonstrate how a candidate region may be generated when we are restricted to a certain reactor type, such as a PFR. 

In this section, the AR for the CH4 steam reforming and water-gas shift reaction will be investigated. This system involves two independent reactions involving five components. Ordinarily, generation of the AR for this system would involve the construction of a two-dimensional AR. For this example, the interest will also be in understanding the minimum reactor volume achievable. Reactions of all components occur in the gas phase under nonisothermal conditions. The ideal gas equation of state is hence not a suitable one for this system. Instead, the Peng-Robinson equation of state shall be employed for this purpose. 

Since the minimum reactor volume is also to be investigated, the associated AR should include residence time. This increases the dimension of the problem. Hence, the AR to be computed will reside in Zcq-Zjh -ct space. The mass fraction and rate vectors are therefore defined as z= [z o, [Pg.296]

Moreover, although the result may not appear significant, the fact that the AR can be computed at all bears special meaning the AR for a non-ideal system involving temperature dependence and minimum reactor volume has been found. From the results of the construction, the AR in mass fraction space can be converted to an equivalent AR in concentration space. An appropriate objective function may then be overlaid to determine its intersection with the boundary. Optimization of the system may then follow. From this, deeper insights into the limits of the system can be obtained. 

Figure 7,7 (a) a plot of minimum reactor volume versus Pd requirements compares methanol reforming on Cu/Zn0/Al20 and methanol decomposition on Pd/Si02- Thin Pd membranes and fibre supports lead to reduced volume and Pd needs, (b) a plot of minimum reactor volume versus Pd requirements compares methanol reforming on Cu/Zn0/Al202 with methanol partial oxidation on CU/AI2O, (Source After Ref [108])... 

From Figure 6.3.6, we can now determine the optimal pathway to minimize the reactor volume by the locus of the maximum rate for a given conversion. The corresponding minimum reactor volume and minimum mass of catalyst is given by [see also Section 4.10.3.4, Eq. (4.10.85)] ... 

If the reactor can operate with a reaction time of either 10,20,30,40, or 50 minutes at a time, what is the minimum reactor volume to achieve a production rate of 150 lb moles/h of P7 Also calculate the maximum volume that will provide the desired results. 

DETERMINATION OF THE MINIMUM REACTOR VOLUME FOR THE ISOMERIZATION REACTION... 

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