Pulp containing paraffin wax is to be dewaxed in a continuous countercurrent extraction system using kerosene. The pulp containing the wax is kerosene-free when entering the extractor, and contains 20% paraffin wax and 80% pulp. After extraction, it must not contain over 0.2 lb wax / 100 lb wax-free pulp. The kerosene used for the extraction contains 0.05 lb of wax per 100 lb kerosene. Experiments show that the pulp retains 2.0 lb of kerosene per lb of kerosene- and wax-free pulp as it is transferred from cell to cell. The extract from the extraction battery is to contain 5 lb wax per 100 lb of kerosene. How many stages are required?

A well-mixed stirred tank reactor has a volume of 200 L. The feed to the reactor is a stream with a flow rate of 50 L/min that has a concentration of species A equal to 5 moles/L. This species undergoes a reaction in the tank of the form

A ----> B

The rate of the reaction (rate of consumption of A) is given by rA=kCa with K = 4 min-1. The exit stream from the reactor is also 50 L/min assume all solutions have the same density.

a. What is the steady state concentration of A in the exit stream?

b. After the steady state is reached, if at some time the inlet concentration of A is changed to 4 moles/L, derive the resultant exit concentration of A as a function of time and find out the time elapsed for the tank to reach again steady state.

A tank contains 800 kg acetone. A steady stream of acetone is added to the tank at a rate of 1200 kg/hr. At the same time a stream is withdrawn from the tank at a rate that increases with time. Initially the withdrawal rate is 800 kg/hr and four hours later the rate is 1000 kg/hr.

a. Derive the differential equation that describes the mass of acetone in the tank.

b. Solve your equation derived in part a.

c. Calculate the maximum amount of acetone in the tank and the time it takes to empty the tank.

In a constant volume batch reactor, enzyme E catalyzes the transformation of reactant A to product R as follows:

A -----> R

The rate of consumption of A is given as rA= 200CACE/(2 + CA) (mol/l min). If we introduce enzyme with an initial concentration of 0.001 mol/l and reactant with an initial

concentration of CA0=10 mol/l into a constant volume batch reactor and let the reaction proceed, find the time needed for the concentration of reactant to drop to 0.025 mol/l. Note that the concentration of enzyme remains unchanged during the reaction.

Draw (by hand is fine) P-T phase diagrams for water (do not worry about multiple solid phases) and for a compound that is not water. Label the phases, the coexistence curves, and the sign of dP/dT for the curves. Also, explain the reason for the sign of dP/dT and what happens to pressure as temperature is increased for each curve.

Methane gas (CH4) at -10°C is burned with pure O2 at 5°C. The O2 is fed at a mol ratio of 1.8:1 relative to CH4. The flue gases leave at 90°C. All compounds exit in the gas phase. Assume the system is at steady state and no work is done. DHo f, CH4, gas = -74.84 kJ/mol Cp (for all gases and vapors): 30 J/mol.K DHo f, CO2, gas = -393.51 kJ/mol DHo f, H2O, gas = -241.83 kJ/mol a) What is the limiting reactant? b) Calculate the heat released per mol of O2 c) What would happen to the heat released per mol of O2 if we did the following: i) Increase temperature of reactants ii) Increase temperature of products iii) Increase feed ratio to 2 mol O2 : 1 mol CH4

Cite two examples of where Ion Exchange is used in Industry (any method, anionic, cationic or

mixed bed), what is being removed, and why.

A spherical particle having a diameter of 9.3 x 10^-3 inches and a specific gravity of 1.85 is placed on a horizontal screen. Air is blown through the screen vertically at a temperature of 20 oC and a pressure of l atm. Calculate the following:

(a) Velocity required to just lift the particle.
(b) Particle Reynolds number at the condition of part (a).
(c) Drag force.
(d) Drag coefficient C_D.

Given;

Viscosity of air = 1.23 x I0 ^-5 lbm/ft.s

Density of air = 7.52 x 10^-2 lbm/ft3

Gravitational constant (gc) = 32.2 lbm.ft/lbr.s2

Saturated steam at 300°C is used to heat a counter-current flowing stream of methanol vapor from 65°C to 240°C in an adiabatic (no heat exchange with surroundings) heat exchanger. The flow rate of methanol is 400 kg/minute, and the steam condenses and leaves the heat exchanger as liquid water at 90°C.

Calculate the required rate of heat transfer from the water to the methanol in kW. Then, calculate the required flow rate of entering steam in m3/min.

Can someone give file of the article about solvay process to manufacture the sodium carbonate

A plant must distill a mixture containing 70 mol% methanol and 30 mole% water. The overhead product is to contain 99 mol% methanol and the bottom product 1 mol% methanol. The feed is at its bubble point, a total condenser is used with a reflux ratio of 1.8 and with the reflux is at its bubble point. A kettle-type partial reboiler is used; the column is operated at 1 atm.

Use the McCabe-Thiele method to determine the number of trays needed to meet process specifications and the optimal location of the feed tray.

3. We wish to determine the thermal conductivity of an apple (= 950 kg/m3, Cp = 3200 J/kg K), which can be considered to be a sphere of radius R = 4 cm. To do this, we design an experiment in which a thermocouple is placed at the center of the apple. A rubber sphere of known properties (= 980 kg/m3, Cp = 1910 J/kg K, k = 0.17 W/m K) and the same radius (4 cm) is also provided with a thermocouple placed at its center. Both the apple and the rubber sphere are initially at 25 °C and they are immersed simultaneously in a perfectly-mixed water bath at 75 °C. After a certain time has passed, the two thermocouples read: Apple: 72 °C, rubber sphere: 45 °C. (a) Determine the thermal conductivity of the apple and the time at which the temperature readings were taken. (b) How much thermal energy (J) has been removed from the water bath during this process?

Air within a piston–cylinder assembly, initially at 15 lbf/ in.², 510°R, and a volume of 6 ft³, is compressed isentropically to a final volume of 1.75 ft³.


Assuming the ideal gas model with k = 1.4 for the air, determine the:

(a) mass, in lb.

(b) final pressure, in lbf/in.²

(c) final temperature, in °R.

(d) work, in Btu.