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During the internal audit of ISO14001, HBN Power Plant was requested to monitor their air emission and water discharge

Mechanical Engineering

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During the internal audit of ISO14001, HBN Power Plant was requested to monitor their air emission and water discharge. As reported, there are 3 zones in the HBN Power plant. Zone 1 of HBN Power plant is burning coal that consists of 2% sulfur. As the fuel is burning at a rate of 2 kg/sec, it was found that 3% of the sulfur content left in the ash. Due the burning of coal, sulfur is oxidized to become sulfur dioxide. A stack (S101) with 1.5m diameter is installed to emit the gas that contains SO2 to the environment in zone 1. The usual stack height is range between 100m to 150m. The plume exit the stack at 17 m/s with 250°C. An air pollutant measuring device is installed at the centerline on the ground level located 2 km downwind. The average wind speed in this area is 3 m/s, temperature of 30°C, pressure of 101.325 kPa during slightly sunny day.

Other than that, the emission from a furnace located in Zone 2 contains 700 μg/m3 of particulate matter (PM10). The flowrate to the baghouse is 1500 m3/min with maximum filtering velocity for PM10 of 0.0417 m/s.

After the baghouse filter, the particulate matter in this gas stream is transferred to an electrostatic precipitator to further remove the particulate matter. The gas stream at 80°C is flowing across the electrostatic precipitator at a rate of 1500 m3/min. The dynamic viscosity of the gas stream is 1.81 x 10-5 Pa.s. The particulate matter passing through the electrostatic precipitator has diameter of 8 μm on average with particle charge of 1.6 x 10-18 C. The electric field applied across the plate is 65,000 V/m.

In zone 3, three discharges and emission were detected. It was found that significant amount of nitrogen oxide is emitted into the air. On top of that, solid waste such as ashes and pressed cake is disposed to the landfill in Zone 3. Last but not least, a wastewater stream that contains high concentration of nitrogen is discharged into a river nearby the power plant.

The emission limit of annual average National Ambient Air Quality Standard for SO2 (NAAQS) is 80 μg/m3

3 The emission limit of PM10 in Malaysia Ambient Air Quality Standard is 40 μg/m .

 

1. Discuss the effect of excessive air emission of SO2 and particulate matter from HBN Power Plant. Then, discuss whether there is a possibility of causing photochemical smog with the all the different type of emissions that HBN Power Plant is emitting.
2. Explain the implication of ISO14001 for HBN Power Plant.
3. Calculate the annual SO2 emission in Zone 1 based on a stack height that you have chosen for HBN Power Plant. Then, predict the concentration that will be recorded by the measuring device located at the centerline at the ground level located 2 km downwind in Zone 1.
4. You are required to choose the number of compartment, number of bags per compartment, and diameter of each bag to be installed in the baghouse filter. Calculate the height of the baghouse filter in Zone 2 based on your chosen parameters. In addition to that, predict the efficiency of the electrostatic precipitator installed in Zone 2. You are required to choose the number of collection plates and dimension for each collection plate. Discuss the effect on the efficiency of electrostatic precipitator when the inlet gas stream experiencing reduction in temperature. Assume that the PM removal is 1313 ?g/m2 of the fabric of the baghouse filter. Identify the overall removal efficiency of combining baghouse filter and electrostatic precipitator of your chosen design. Discuss whether the combination of baghouse filter and electrostatic precipitator is sufficient to treat the particulate matter in Zone 2 to meet the Malaysia Ambient Air Quality Standard.
5. Identify the possible impacts and consequences that could associate with the discharge of high nitrogen concentration wastewater into the river in Zone 3.
6. According to Solid Waste and Public Cleansing Management Act 2007, municipal solid waste needs to be disposed to a properly designed landfill. Demonstrate the essential design components of a municipal solid waste landfill in details for Zone 3.