Problem 4. Lab experiment - Adiabatic Batch Reactor (Total: 30 Marks) In the lab experiment, you performed the reaction of sodium thiosulphate with hydrogen peroxide in a batch reactor. 2 Na2S2O3

Two tanks are connected together in the following unusual way in Fig. E2.3. Develop a model for this system that can be used to find hj, h2,W2, and w3 as functions of time for any given variations in inputs. 1. The density of the incoming liquid,p, is constant. 2. The cross-sectional areas of the two tanks are A1 and A2. 3. w2 is positive for flow from Tank 1 to Tank 2. 4. The two valves are linear with resistances R2 and R3.

A completely enclosed stirred-tank heating process is used to heat an incomingstream whose flow rate varies. The heating rate from this coil and the volume areboth constant. Develop a mathematical model for the process if the heat losses tothe atmosphere occur. 1. p and Cpare constants. 2. U, the overall heat transfer coefficient, is constant. 3. A, is the surface area for heat losses to ambient. 4. T; > Ta (inlet temperature is higher than ambient temperature).

2. The second-order decomposition reaction A \rightarrow B+2 C is carried out in a tubular reactor packed with catalyst pellets 0.4 cm in diameter. The reaction is internal-diffusion-limited. Pure A enters the reactor at a superficial velocity of 3 m/s, a temperature of 250°C, and a pressure of 500 kPa. Experiments carried out on smaller pellets where surface reaction is limiting yielded a specific reaction rate of 0.05 m^6/mol•g-cat•s.Calculate the length of bed necessary to achieve 80% conversion. Critique the numerical answer. (Ans.: L =2.8 *10-5 m) Additional information: * Effective diffusivity: 2.66 *10-8 m²/s * Pellet density: 2 106 g/m^3 * Internal surface area: 400 m^2/g * Bed porosity: 0.4

1. Consider the series reaction below. The overall yield of D is 60%, at a 40% conversion of A. What is the overall selectivity to D with respect to U, so SDU at these conditions? A → D→U

The liquid-phase irreversible reaction A→B + C is carried out in a Batch Reactor. To learn the rate law, the time is varied and the effluent concentrations of species A are recorded as a function of time. Pure A enters the reactor at a concentration of 2 mol/dm³. Steady-state conditions exist when the measurements are recorded. Determine the reaction order and specific reaction rate constant A. Using the Differentiation Method. B. Using the Integral Method C. Using Nonlinear Regression (Homework in Recitation; Already Completed) D. Assume this works as aCSTR, is everything the same? (Recitation Example;Already Seen)

A closed stirred-tank reactor with two compartments is shown in Fig. E2.6. The basic idea is to feed the reactants continuously into the first compartment, where they will be pre-heated by energy liberated in the 2nd order exothermic reaction2A→B, which is anticipated to occur primarily in the second compartment. The wall separating the two compartments is quite thin, thus allowing heat transfer;the outside of the reactor is well insulated; and a cooling coil is built into the second compartment to remove excess energy liberated in the reaction. Develop a mathematical model for this process.

The elementary parallel reactions 25 > D Are carried out in a packed bed reactor in that has a significant pressure drop. If there no internal or external mass transfer limitations, when the catalyst particle size increases,the selectivity A. Decreases B. Increases C. remains the same D. Insufficient information

An experimental rate measurement is made on the decomposition of A using a spherical catalyst with the following data: Is it likely that film resistance to mass transfer influences the rate of reaction?

In this exercise we propose to study the kinetics of the formation of methane from hydrogen and carbon monoxide over a nickel catalyst. \mathrm{CO}+3 \mathrm{H}_{2} \leftrightarrow \mathrm{CH}_{4}+\mathrm{H}_{2} \mathrm{O} The use of a differential reactor gave the following rate expression: \mathrm{r}_{\mathrm{CH} 4}^{\prime}=\frac{0.0183 \mathrm{P}_{\mathrm{HZ}}^{1 / 2} \mathrm{P}_{\mathrm{CO}}}{1+1.5 \mathrm{P}_{\mathrm{H} 2}} The following mechanism has been proposed: \mathrm{H}_{2}+\mathrm{S} \longleftrightarrow \mathrm{k}_{1} \longrightarrow \mathrm{H}_{2} . \mathrm{S} \mathrm{H}_{2} . \mathrm{S}+\mathrm{S} \leftrightarrow \mathrm{k}_{2} \longrightarrow \mathrm{H} . \mathrm{S}+\mathrm{H} . \mathrm{S} \text { H.S }+\mathrm{CO} \leftrightarrow{ }_{4} \longrightarrow \mathrm{CHO} . \mathrm{S} \text { CHO.S + H.S\longleftrightarrow } \stackrel{k_{4}}{\longrightarrow} \text { C.S }+\mathrm{H}_{2} \mathrm{O}+\mathrm{S} \mathrm{C.S}+2 \mathrm{H}_{2} \stackrel{\mathrm{k}_{5}}{\longrightarrow} \mathrm{CH}_{4}+\mathrm{S} (1) Show that the mechanism is consistent with the proposed rate expression. You will assume that reaction 3 is the rate determining step and that reaction 5 is irreversible. Also, the equilibrium constant for reaction 1 is several orders of magnitude greater that the equilibrium constant of reaction 2. Make appropriate assumptions (and justify them) when needed.where Ki =k-1/k-1; K2 = k/k-z; K3 = k/k-3; Ka = kak4 (2) The feed consists of 75% Hz and 25% CO at a pressure of 10 atm. Determine the fraction of sites covered by H2. What do you conclude?

Given the discussion on the different reactor types and the assumptions that are used in developing mole balances for each reactor type, answer the following: 1) (5 points) State an assumption that is the same between a batch reactor and a CSTR. 2) (5 points) State an assumption that is different between a batch reactor and a CSTR. 3) (5 points) State an assumption that is the same between a CSTR and a PFR. 4) (5 points) State an assumption that is different between a CSTR and a PFR.