Methanol is produced by reacting carbon monoxide and hydrogen. A fresh feed stream containing CO and H2 joins a recycle stream and the combined stream is fed to a reactor. The reactor outlet stream flows at a rate of 350 mole/min and contains 10.6 wt% H2, 64 wt% CO and 25.4 wt% CH3OH. This stream enters a cooler in which most of the methanol is condensed. The liquid methanol condensate is withdrawn as a product, and the gas stream leaving the condenser – which contains CO, H2 and 0.4 mole % uncondensed CH3OH vapor – is the recycle stream that combines with the fresh feed. Determine a) the molar flow rates of CO and H2 in the fresh feed b) the production rate of liquid methanol (mol/min) and c) the molar flow rate of the recycle stream.

Five hundred twenty kilograms of aqueous solution containing 185 kg of dissolved MgSO4 is fed to a crystallizer wherein 80% of the dissolved salt crystallizes out as MgSO4·6H2O. The solubility of MgSO4 in the solution leaving the crystallizer is 20 g MgSO4 per 100 g H2O.

A. How many kilograms of the hexahydrate salt crystals are obtained from the crystallizer?

B. How many kilograms of water is evaporated in the process?

Sodium salicylate (HOC6H4COONa) is used in medicine as pain killer. It can be prepared from sodium phenolate (C6H5ONa) and carbon dioxide. Most commonly, solutions of sodium phenolate are produced by treating phenol with sodium hydroxide. Suppose phenol is run into a 30% excess hot aqueous caustic soda (87% NaOH by mass) with 130 m3 dry carbon dioxide at 300 kPa and 100oC per hr. After the desired amount of carbon dioxide is absorbed and reacted, sodium salicylate solution is withdrawn. The solution has a composition of 68.21% HOC6H4COONa, 8.73% C6H5ONa, 5.24% C6H5OH, 8.92% NaOH, and 8.90% H2O. The gaseous stream contains CO2 and H2O. On a basis of 100 kg hot aqueous caustic soda, calculate:

a) kg of salicylate solution/hr

b) degree of completion of the reaction

c) composition of gaseous stream

A mixture of saturated hydrocarbon and N2 us burned in excess air supplied at 25°C, 740 torrs with 90% RH. An orsat analysis of the stack gas shows 7.6% CO2, 2.28% CO, 1.14% H2, 6.03% O2 and 82.95% N2. With a dew point of 53.46°C. The stack gases leave at 300°C, 765 mmHg with a volume ratio of 2.049 m3 wet stack gas/m3 wet air.

a. The formula of hydrocarbon is?

b. Mole % analysis of the fuel

c. % excess air

1. Explain the mechanisms of transport in membranes. Support your explanation with appropriate figures.

2. Explain equations that describe pore resistance (of porous membranes) to bulk flow.

3. Explain equations that describe gas diffusion through porous membranes.

A clarified broth from the fermentation of sucrose using Aspergillus niger consists of 16.94% wt citric acid, 82.69% wt water, and 0.37% wt other solutes. To recover citric acid, the broth would normally be treated first with calcium hydroxide to neutralize the acid and precipitate it as calcium citrate, and then with sulfuric acid to convert calcium citrate back to citric acid. To avoid the need for calcium hydroxide and sulfuric acid, U.S. Patent 4, 25, 671 describes a solvent-extraction process using, which is insoluble in water and has a density of 0.847 g/cm^3. In a typical experiment at 30 C, 50 g of 20% wt citric acid and water was contacted with 0.86 g of amide. The resulting organic phase assumed to be in equilibrium with the aqueous phase, contained 6.39% wt citric acid and 2.97% wt water.

Determine (a) the partition (distribution) coefficients for citric acid and water, and (b) the solvent flow rate in, needed to extract 98% of the citric acid in 1300 kg/ h of broth using 5 countercurrent, equilibrium stages, with the partition coefficients from part (a), but ignoring the solubility of water in the organic phase. In addition, (c) propose a series of subsequent stages to produce near-pure citric acid crystals. In part (b), how serious would it be to ignore the solubility of water in the organic phase? 5.10. Extraction

An ideal vapour refrigeration cycle uses RF-134a as the working fluid and consists of the following steps:

(i)        Saturated vapour at 20 psia is compressed adiabatically and reversibly to a pressure of 120 psia. [The compressor]

(ii)       The vapour is cooled and condensed at constant pressure, leaving the condenser as a saturated liquid. [The condenser]

(iii)      The saturated liquid is expanded through a throttling valve to a pressure of 20 psia. [The throttling valve]

(iv)      The liquid-vapour mixture leaving the throttling valve is heated at constant pressure until it is 100% saturated vapour. [The evaporator]

The flow rate of refrigerant in this cycle is 0.1 kg s^-1.   For this cycle do the following:

(a)        Plot the cycle on the attached P-h chart for RF-134a.                                  

(b)       Calculate the power input to the compressor in kW.                                     

(c)        Calculate the heat transferred to the environment in the condenser in kW.  

(d)       Calculate the coefficient of performance (as a refrigerator) for the cycle.     (5marks)

Total = 20 marks

Note: Use the attached P-H chart for R-134a as your data source.

            1 kg = 2.21 lbm

            1 J = 9.48*10^-4 Btu

            1 bar = 10⁵ Pa = 14.5 psia

In detail explain, what are the challenges/competition facing the Oil & Gas industry over the next 10 years and whether it has a future?

Differentiate the advantages of centrifugal filtration and centrifugal decantation.

Liquid air is available (79 mol% of nitrogen and 21 mol% of oxygen) and it is required to obtain a fraction whose oxygen content is 90% (mol), for which part of the mixture evaporates to the atmospheric pressure. Determine the fraction of evaporated mixture, taking as the average value of relative volatility 4.12

i.The current density of a fuel cell is 0.61 A cm-2. Assume the water generated remains in the liquid phase and no water is ejected from the stack during operation, calculate the time required for 1 mg cm-2 liquid water to accumulate in a fuel cell.

ii.Explain the process that determine water dynamics in a polymer electrolyte fuel cell. Use a diagram to help explain the different processes, where water is generated and the direction and mechanism by which it is transported

A pond 2 m in diameter is to be filled with water by a flow that varies linearly with the level of the pond so that it reaches the maximum value of 217 lt/h when the pond is empty and is zero when the level reaches 2 m. Calculate: a) Time it takes to reach the level of 1 m. b) Time it takes to fill up completely. Discuss this last result.

. Limestone containing 85.5 % CaCO3, 6% MgCO3, 2.5% Fe2O3 and 1.5% SiO2 and rest water is calcined (thermally decomposed) in hot air to vaporize H2O and separate CO2 from the carbonates The CaO and MgO are created by the reaction leave in the solid calcine, along with hematite and silica. How many kilograms of calcine will be produced per metric ton of limestone?

   CaCO3 → CaO + CO2                                                            MgCO3 → MgO + CO2

. Limestone containing 85.1 % CaCO3, 6% MgCO3, 2.5% Fe2O3 and 1.5% SiO2 and rest water is calcined (thermally decomposed) in hot air to vaporize H2O and separate CO2 from the carbonates The CaO and MgO are created by the reaction leave in the solid calcine, along with hematite and silica. How many kilograms of calcine will be produced per metric ton of limestone?

   CaCO3 → CaO + CO2                                                            MgCO3 → MgO + CO2