Let’s consider a portable UV disinfection system to be used with 5-gallon (18.9 L) coolers with a modified lid. The setup will allow water to flow into the top and out a spigot at the bottom. The resulting contactor is effectively a CSTR.

1. If the disinfection rate constant for UV₂₇₈ is 6.3 s^-1 for E. coli, what is the maximum flow rate that the system can handle to achieve 99 percent inactivation? (answer in L/min)

2. If you decide to operate the device in batches instead of in a flow-through mode, how long should you wait to achieve 4-log inactivation of E. coli? (answer in min)

The International Space Station uses the electrolysis of water to continuously replenish the oxygen in the station’s atmosphere (the hydrogen formed is vented). The station’s electricity is generated by the four arrays of solar modules, which produce a total of 120 kW. Essential heating/cooling, circulation and steering equipment requires 75 kW. If one of the four modules fails completely, this leaves 15 kW for O₂production, which is run at a 2 V potential. How many astronomers can survive on board of the space station if each of them consumes 25 L of O₂(g) per hour? Enter your numerical answer (rounded DOWN to the closest whole number, as we cannot have partial astronauts!) in the answer box. Assume 1 atm and 298 K as conditions.

To help you solve this problem, use the following information, suggested steps and hints:

        a) Write the balanced half reactions at each electrode and the overall reaction!

b) If the electrolysis is carried out at 2 V potential, how many moles of electrons are produced in 1 s? (Hint: Calculate the Ampere available first using the following relationships: 1 W = 1 J/s; 1 J = 1 V·1 C; 1 C = 1 A·s)

c) Using your results from a) and b), how many moles of O₂ can be produced in 1 h?

d) How many moles of O₂(g) are required each hour for one astronaut, if s/he consumes 25 L of O₂(g) per hour? Assume 1 atm and 298 K.

e) How many astronauts can survive on the O₂ produced in c) if each consumes the number of moles calculated in d)?

1. Consider a feed containing benzene, toluene, and cumene with mole fractions of 0.25, 0.5, and 0.25, respectively. The relative volatilities of these components with respect to toluene is 2.25, 1,and 0.21. If the fractional recovery of benzene in the distillate is 0.9 and that of toluene in the bottoms is 0.9, solve for the component flow rates in the bottoms and distillate using the Fenske equation. Assume that the feed flow rate is 100 kmol/hr.

2. Assume that the feed in Problem 1 is saturated liquid. What is the minimum reflux ratio? Use the Underwood equation and toluene as the reference component.

A copper pipe of diameter 3.5 cm and wall thickness 4 mm is used in an antibiotic factory to convey hot water a distance of 60 m at a flow rate of 20 L/s. The inlet temperature of the water is 90°C. Due to heat losses to the atmosphere, the outlet water temperature is 84°C. The ambient temperature is 25°C. The inside of the pipe is covered with a layer of fouling with a fouling factor of 7500 W/m²°C.

1. What is the rate of heat loss from the water in kW?
2. What proportion in percentage (%) of the total resistance to heat transfer is provided by the fouling layer?
3. If the copper pipe were replaced by a clean stainless-steel pipe of the same thickness, what proportion in percentage (%) of the total resistance to heat transfer would be provided by the pipe wall? To answer this question you need to estimate this ratio and multiply by 100%: B/k1/Ux 100%   where B is the pipe-wall thickness, k is the thermal conductivity of stainless-steel

Steam used to sterilize fermentation equipment is piped 20 m from a factory boiler room through a 6-cm-diameter tube. The surface temperature of the steam pipe is roughly constant at 118°C. Most of the length of the tube lies unprotected and exposed to the outside weather. The air temperature is 5°C and the wind speed is 7.5 m/s. The properties of air at 330 K are: C_p=1007 J/kg°C, k_fb=0.0283 W/m°C, ρ=1.076 kg/m³, and µ_b=1.99∙10^-5 kg/m∙s.

Estimate rate of heat loss from the pipe in kW

List the basic principles of the distillation tower at least 4 principal
and why there are several design techniques?

please my friends I need the answer in obvious script.

A piston-cylinder device initially contains 0.20(kg) of steam at 3.5(MPa), 300(C). The steam loses heat to the surroundings and the piston moves down, hitting a set of stops at which point the cylinder contains saturated liquid water. The cooling continues until the cylinder contains water at 220C.

A) Sketch the above process on a P-v chart, indicating values

B) Determine the pressureand qualityof the final mixture.

C) Determine the boundary work (in kJ)

1) A gas mixture containing 75% air, 20% of A and 5% of B (by volume) is in equilibrium
with an aqueous solution of A and B at a temperature such that the saturation pressure
of pure A is 3 bar, and that of pure B is 8 bar. Estimate the composition of the liquid if
the total pressure is 2 bar. State any assumptions you have made.

Drug delivery systems are often ‘pelletized’ as spheres. Construct the control volume. Determine the continuity equation and the steady-state, spherical flow rate of medicine. Model the drug as an incompressible fluid.

Why must a power cycle release heat at some point

Air is cooled from 300 K to 273 K as it flows steadily through a duct. Frictional dissipation may be neglected. Cooling is achieved by removing heat via a heat pump. The work requirement is 1.15 times that of a reversible heat pump operating between 263 and 310 K. For each mole of air flowing through the duct, calculate: Air can be assumed an ideal gas with a constant heat capacity cP of 3.50R. The temperature of the surroundings is 300 K

a) Total irreversibility in J/mole

b) Irreversibility due to heat transfer between air and the heat pump

c) Irreversibility due to heat transfer between the heat pump and the surroundings

d) Internal irreversibility of the heat pump