Steam at 400°C and 40 bar flows steadily through an adiabatic
turbine at a volumetric
flowrate of 5,000 m3/h. The steam leaving the turbine at 1 bar is
then cooled at constant
pressure in a condenser to 25°C. The rate of transfer from the
condenser is 50 MW.
Calculate the power output generated by the turbine (MW). Clearly
state assumptions (if
any) and reference state.
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The ammonia gas (mw = 17 kg/kgmol) at 40 oC and 3 atm was transported at flowrate of 5 kg/h by an insulated pipeline having the total thickness of 2.0×10-3 m. The pressure and temperature of the ammonia gas suddenly drop to ambient temperature and pressure of 25 oC and 1 atm. A thorough investigation showed that the ammonia gas leaked to surrounding atmosphere through a pipeline wall cracking hole having an equivalent diameter of 3 mm.
a) State all the assumptions. Determine the mass rate of ammonia gas lost to surrounding atmosphere as well as the mass contamination rate of ammonia gas in the insulated pipeline by air (mw = 28.97 kg/kgmol).
b) Determine the mole fraction air in the pipeline. If repairing the pipeline required 5 hours, how much ammonia gas was lost from the incident.
Given: Ammonia-air diffusivity, DAB at 298.0 K is 2.8×10-5 m2 /s. The ammonia gas and air at those conditions could be assumed obeyed an ideal gas law. The universal gas constant, R is 8.205×10-2 m3 atm/kmol.K.
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Q3)
Briefly write the biomass potential in Malaysia. Describe the efficient thermodynamic cycles that could be used to convert biomass energy for industrial applications.
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By using an appropriate example and diagram, explain the steady state diffusion of component A through non-diffusing component B for molecular diffusion of gases.
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All normally ductile polymers can also craze even in the absence of solvents, given the right circumstances. The crazing stress of each polymer is slightly sensitive to temperature but insensitive to strain rate. Ductile to brittle transition temperature (Tb) are often found at low temperatures for such polymers; explain why Tb shifts to higher temperatures at increasing strain rates. (Hint: the easiest way to explain this is to use diagrams. If you do, be sure the label the curves and explain briefly what they mean.)
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Explain how electricity is produced using a hydrogen fuel cell.
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Consider the wall of Gypsum, Insulation, Concrete and Brick. It is located in a city for which the CDD is 800°C.days. The total area of the wall is 600 m2. The interior space is occupied and maintained at constant temperature 24 hours a day for a year. use the information below to answer these questions.
Tinside= 21°C
Toutside= 18°C
Gypsum: x=0.01 m, C=20 W/m2∙°C
Brick: x=0.12 m, k= 1 W/°C
Insulation: x=0.025 m, k= 0.04 W/°C
Block: x=0.20 m, C=5 W/m2∙°C
How much energy is required to cool the building over a year in GJ?
What is the cost to provide this energy if the cooling system is electrically and electricity costs $0.10/kWh with The COP for the cooling system is 2.4?
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A tank that initially contains H2O at 0.05 MPa and 100 ºC, is connected to a water vapor line at 0.60 MPa and 200 ºC and is filled to a level where 90% (on a volumetric basis) is liquid. The 1 m3 tank is kept at 100 ºC during the process. Determine the quality of the gas in the second phase, the input mass in (kg) and the heat transfer, in kJ.
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Using the information below, produce a set of calibration
figures for the
control loop TICA1495.
TI1495 range = 100 to 420°C
TICA1495 SP = PV = 300°C
TCV1495 = 30%.
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Which of the following statements are true and which are false?
The decimal reduction time D is the heating time in min at a certain temperature required for the number of viable microbes to be reduced to 10% of the original number.
The z value is the temperature increase required for a ten-fold decrease in D.
Thermal death time is the heating time required to give commercial sterility.
Thermal death time does not depend on the initial microbial load.
The D value does not depend on the initial microbial load.
The D value of a microorganism is independent of the food item.
The D value of a microbe is a measure of the thermal resistance of the microbe.
If the number of microbes in a process has to be reduced from an initial load of 106 to a final 104, the required thermal death time will be 10D.
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