Chemical Engineering Answers

CaCO3 precipitate is made by reacting CaO with an aqueous solution of Na2CO3, the by-product being NaOH. After decanting, slurry leaving the precipitation tank is 5% w/w CaCO3, 0.1% NaOH, and the balance water. 100 000 kg hr–1 of slurry is fed to a two-stage counter-current continuous washing system to be washed by 200 000 kg hr–1 of fresh water. Underflow from each unit contains 20% w/w solids. Calculate fraction of NaOH recovered and mass percentage NaOH of dried product. Would adding a third stage be worthwhile? 

An ideal gas is undergoing a process in which temperature and volume relation is Tav-25 Calculate the work done by the gas is going from state -1 in which pressure is 100 bar and the volume is 4 m to a state-2 in which the volume is 2 m. Also calculate the pressure at the state-2 of the system. 

I need help with a transport assignment.

What are the major petrochemicals processes to form the intermediate compounds (second generation petrochemicals), with examples?

Use the Peng-Robinson equation of state to calculate the binary interaction coefficient (k12) of a {2 + (X × 0.5)} 

m3

vessel that contains {30 + (0.15 × Y)} kg of propane mixed with {50 + (Z × 0.3)} kg of n-butane at 30 bar and 

450 K.

𝑃 =

𝑅𝑇

𝑉 − 𝑏𝑚𝑖𝑥

−

𝑎𝑚𝑖𝑥

𝑉2 + 2𝑏𝑚𝑖𝑥𝑉 − 𝑏𝑚𝑖𝑥

2

𝑓𝑜𝑟 𝑒𝑎𝑐ℎ 𝑝𝑢𝑟𝑒 𝑐𝑜𝑚𝑝𝑜𝑛𝑒𝑛𝑡: 𝑎 = 0.45724

𝑅

2𝑇𝑐

2

𝑃𝑐

× [1 + (0.37464 + 1.54226𝜔 − 0.26992𝜔

2

)(1 − 𝑇𝑟

0.5

)]

2

𝑎𝑚𝑖𝑥 = ∑𝑖 ∑𝑗 𝑥𝑖𝑥𝑗𝑎𝑖𝑗 𝑎𝑖𝑗 = (𝑎𝑖𝑎𝑗)

0.5

(1 − 𝑘𝑖𝑗)

𝑓𝑜𝑟 𝑒𝑎𝑐ℎ 𝑝𝑢𝑟𝑒 𝑐𝑜𝑚𝑝𝑜𝑛𝑒𝑛𝑡: 𝑏 = 0.07780 𝑅𝑇𝑐

𝑃𝑐

CPT 307 ASSIGNMENT

The Figure below shows a cross section through an insulated heating pipe which is made from steel (k = 45 W / m K) with an inner radius of 150 mm and an outer radius of 155 mm. The pipe is coated with 100 mm thickness of insulation having a thermal conductivity of k = 0.06 W / m K. Air at Ti = 60°C flows through the pipe and the convective heat transfer coefficient from the air to the inside of the pipe has a value of hi = 35 W / m2 K. The outside surface of the pipe is surrounded by air which is at 15°C and the convective heat transfer coefficient on this surface has a value of ho = 10 W / m2 K. Calculate the heat loss through 50 m of this pipe. 

A fuel is analyzed and found to contain; 75.0 wt% methane, 10.0% ethane, 5.0% ethylene and the balance water. The flowrate of the fuel is 102.7 kg/h. Calculate the molar composition of this gas on both a wet and a dry basis and the ratio(mol H2O/ mol dry gas). If tgis fuel is to be burned with 28% excess air, what is the required air feed rate (kmol/h)? How would the answer change if the combustion were only 40% complete?

1 kg of ait at 1 bar 15 degree centridage is compressed reversibly and adiabtically in a pressure of 4 bar.Calculate the final temperature and the work input.

An absorption operation is required to remove CO2 from a 250 kmol/hr flue gas stream using an aquaeous 20 mole% MEA solution supplied at a flow rate of 1.5 times the minimum. The gas feed contains 13 mole% CO2 in air, and the exhaust gas stream should contain no more than 0.7 mole% CO2. The supplied MEA solution contains 1.1 mole% CO2. This absorption operation column has internal height and diameter of 10 and 1 m, respectively. The column should be designed for a pressure drop of 0.5 inches H2O per foot of packing.

a) Determine the mole% CO2 in the liquid stream leaving the column and determine the number of transfer units.

Equilibrium data:

x:0.010 0.0125 0.015 0.0175 0.020 0.0225 0.025 0.0275 0.030 0.035 0.040 0.045 
y:0.002 0.005 0.009 0.015 0.021 0.028 0.037 0.047 0.059 0.090 0.135 0.19 

Other data:

𝑀̅𝑠𝑜𝑙𝑣𝑒𝑛𝑡 = 26.6, 𝑀̅CO2 = 44 g.mol-1 , kOG = 0.85 mol.m-2 .s-1 , ρg,ave. = 1.28 kg.m-3 , ρl,ave. = 1000 kg.m-3 , ηave. = 1.0 cSt

condition of water-

U=2500KJ/KG, T=70C

Determine state of water.