Problem 4. A benzene-air mixture is to be scrubbed in a simple counter-current absorption tower using a non-volatile hydrocarbon oil as solvent. The inlet gas contains 5% benzene and the enriching gas flow is 600 kmol/hr. Solubility of benzene in oil follows Raoult's Law. The tower operates isothermally at 80°F. The average molecular weight of oil is 200 and the pressure is 1 atm. [PC,H, = 103 mm Hg at 80°F.] (a) Calculate the minimum liquid flow rate needed to recover 90% of the entering benzene. (b) Calculate the theoretical stages required if Qal=1.5QL

One integrated circuit design calls for the diffusion of arsenic into silicon wafers; the background concentration of As in Si is 2.5 × 1020 atoms/m³. The predeposition heat treatment is to be conducted at 1000°C for 45 minutes, with a constant surface concentration of 8 x 1026 As atoms/m³. At a drive-in temperature of 1100°C, determine the diffusion time required for a junction depth of 1.2 μm. For this system, values of Qd and Do are 4.10 eV and 2.29 × 10-³ m²/s, respectively. hours

In a counter-current absorption tower, a process gas containing 0.04 (mole fraction) ammonia is scrubbed with pure water. The exit gas contains 0.002 (mole fraction) ammonia.The diameter of the tower is 1m, and the packing has a large area per volume of 200 m2m–3. The overall mass transfer coefficient based on the liquid side driving force, KL, is 1.5×10−5ms–1. The total gas and liquid concentrations are 0.6kmolm–3and 20 kmolm–3respectively and the gas flowrateis 0.03kmols–1. The actual liquid to gas ratio is 1.5 times that of the minimum liquid to gas ratio. The equilibrium for ammonia between the air and water is given by y* = 1.04x. What is the mol fraction of ammonia in the liquid?

The heat changes that take place in chemical reactions or physical state transitions can be measured. The heat change and the change in enthalpy is: Heat change does not affect enthalpy. O smaller than the change in enthalpy O equal to the change in enthalpy O greater than the change in enthalpy MacBook Air

er%20Fundamentals%20and%20Applications... Q and 1100 W/m².K, respectively. The heat exchanger has a heat transfer surface area of 2.5 m², and the estimated fouling factor caused by the accumulation of deposit on the surface is 0.0002 m² K/W. The hot fluid (c, = 3800J/kg-K) enters the heat exchanger at 200°C with a flow rate of 0.4 kg/s. In the cold side, cooling fluid (c = 4200 J/kg-K)enters the heat exchanger at 10°C with a mass flow rate of 0.5 kg/s. S e of 10 nd is er- ra- ate un- an ater the for cold heat mine erall 11-104 Cold water (c₂=4180 J/kg-K) leading to a shower enters a thin-walled double-pipe counterflow heat exchanger at 15°C at a rate of 0.25 kg/s and is heated to 45°C by hot water (cp=4190 J/kg-K) that enters at 100°C at a rate of 3 kg/s. If the overall heat transfer coefficient is 950 W/m2.K, determine the rate of heat transfer and the heat transfer surface area of the heat exchanger using the e-NTU method. Answers: 31.35 kW, 0.482 m² Hot water A 100°C 3 kg/s 45°C…

8 i. Estimate the dimensions of a drying chamber for a spray dryer that has an output of 1000 kg/h of a heat-sensitive biological material at 60oC containing 5% moisture and having a mean particle size of 100 micrometers. The feed contains 40% solids by weight in an aqueous solution at 4oC. The inlet air has a humidity of 0.01 kg/kg dry air and is at 150oC, while the outlet air is at 80oC.

Which of the following statements is correct regarding TCD detector?

The results of air temperature measurement obtained a dry bulb temperature of 37 ° C and a wet bulb temperature of 27.5 ° C. Using a psychrometric chart, determine the properties of the air as follows:a. RH:%b. Water content: kg water / kg airc. Specific volume: m3 / kgd. Enthalpy: kJ / kge. Condensation temperature: ° CIf the air is within 162 m3 space, determinef. Air weight (dry air and water vapor): kgg. the amount of water content in the space: kg

Heat Transfer Question

A continuous single-effect evaporator is to be fed with 5000 kg/hr of solution containing 1 wt% solute, the feed is at a temperature of 303 K. it is to be concentrated to a solution of 2 wt% solute. The evaporation is at atmospheric pressure (101.3 kPa) and the area of the evaporator is 69.7 m2 Saturated steam is supplied at 143.3 kPa for heating. It is assumed that the Cp of feed is the same with that of water which is 4.1 kj/kg-K. Assume no BPR. Calculate: overall heat transfer coefficient