Chemical Engineering Answers

A reaction A → Bis to be conducted in two CSTRS in series. The steady state conversion desired is Xf. The reaction rate as a function of conversion is given by r = -1/(1+X). If the feed contains no B, then the conversion in the first reactor that minimizes the total volume of the two reactors is

1-Xf

0.2Xf

0.5Xf

0.5(1-Xf

After recovering all available sugars from your waste stream, you used a chemostat culture of Corynebacterium glutamicum to convert 12 g L-1 glucose to L-lysine. The steady state process was performed

aerobically in a 50 m3 continuous stirred tank reactor (CSTR). The laboratory based performance data

indicated that the yield of biomass from substrate is Yxs is 0.1 g g-1. From your experience, you know

that you can maximise production in continuous reactor systems by maximising the dilution rate.

1. As you had sufficient performance data, you decide to go to your office to determine the lowest

mean residence time τ you can operate to maximise the growth of Corynebacterium glutamicum.

You further calculate the product yield and maximum product yield at this dilution rate on mass

basis. In your calculations you assumed steady state operation.

The working volume of the reactor is 50 m3. The gas flow rate into the reactor is 0.75 vvm (volume gas per volume liquid per minute). Using the instrumentation available to you, you can confirm an inlet and outlet O2 concentration in the gas phase of 40% and 16% by volume, respectively. For the purposes of your calculation, you reasonably assume the flow rate across the reactor is constant. You find that the residual dissolved oxygen concentration in your system is 2.5 mg L-1 and confirm that the saturation dissolved oxygen concentration achieved on sparging water with air at 30oC is 7.5 mg L-1.

1. Knowing that temperature influences the rate of gas-liquid mass transfer, you decide to calculate the saturation dissolved oxygen concentration at 30oC using the enriched gas stream containing 40% oxygen.

2. Using a mass balance across the reactor, you further calculate the Oxygen Utilisation Rate (OUR)

In slurry reactor pure reactant gas is bubbled thought liquid containing suspended catalyst particle.let us view these kinetics in terms of the film theory as shown below in fig p17.3.thus,to reach the surface of the solid the reactant which enter the liquid must diffuse through the liquid film into the main body of liquid and then through the film surrounding the catalyst particle.at the surface of the particle reactant yield product according to first order kinetics.derive an expression for the rate of reaction in terms of these resistance

2 tonnes of galena is to be reduced to fine powder by passing through a crusher and a grinder in succession, drawing powder from the same drive. Screen analysis of feed, product from crusher and product from grinder indicated surface areas of 5, 115 and 1000 m²/kg respectively. If the power required by the drive to run the crusher driver assembly is 20 KW and efficiency of crusher is 20%, find the efficiency of grinder. Rittinger's number for galena is 100 m²/kj

Calculate the range of values for angle of internal friction for which a material is 

flowable.

In a cement manufacturing unit, 36 tonne/h of calcite of 5-cm size is fed to a gyratory crusher. Screen analysis from the crusher shows a surface area of product of 61.7 m2/kg. Thecrushed material is then subjected to fine reduction in a hammer mill. Mill product analysis indicates a surface area of 740 m2/kg. Rittinger s number for calcite is 75.9 cm2/kg.cm. Efficiency of the grinder is 30%. The crusher and grinder are driven on the same shaft (by

an electric motor) whose transmission efficiency is 90%. If 480 hp is fed at

the other end of the shaft, compute the efficiency of the crusher.

In a component manufacturing industry, there is a small probability for any 

component to be defective. The components are supplied in packets of . Use 

Poisson approximation to calculate appropriately the number of packets containing 

 (i) at least one defective (ii) at most one defective in a consignment of 100 packets

t is required to heat 10000 bbl/ day of crude oil (as given in case study of Lecture3) in a

fired still heater from 220 0F to 622 0F and vaporize (gasoline, naphtha, kerosene, light gasoil,

heavy gasoil) of the crude oil using refining gas, (NHV=50000 Btu /lb). In the radiant section

contains 1500 ft2 of projected area, and the tubes (5 in. outside diameter) are spaced at a center-

to-center distance of 10 in. there is only one row of radiant tubes, and they are 40 ft long. The

ratio of air to fuel is 17.

F, average latent heat of vaporization 0 Given: Average Specific heat of the crude oil = 2.3 Btu/ lb

is 120, 113, 100, 95, 90 Btu/lb for (gasoline, naphtha, kerosene, light gasoil, heavy gasoil)

respectively. and the furnace efficiency is 75% calculate:

a) The mass flow rate of the fuel required?

b) How many Btu are absorbed per hour in radiant section?

c) How many Btu are absorbed per hour through each squar

 Estimate the following: (a) The volume occupied by 18 kg of ethylene at 328.15 K (55°C) and 35 bar. (b) The mass of ethylene contained in a 0.25-m3 cylinder at 323.15 K (50°C) and 115 bar.