Fluid flow

Mércia Valéria de Araujo Souza Peixoto

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CEE 6270: Environmental Management and Sustainable Development

04/05/2015

Final Exam

1. 1) m + 2c = x

2) Fraction of the mass consumed from recycling = [pic 1]

    Fraction of the mass consumed from restoration =  [pic 2]

1. Changing coal to natural gas to produce 500 MW.

The environmental impact factor is used to normalize daily values.

        

From the given table:         

  Coal heat value = 24 MJ/kg = 6.67x10-3 MWh/kg = 2.78x10-4 MW-day/kg

  Natural Gas heat value = 52 MJ/kg = 14.44x10-3 MWh/kg = 6.02x10-4 MW-day/kg

Coal (C + O2 → CO2)

1 kg of coal → 2.78x10-4 MW-day

            x kg of coal → 500 MW ,  x = 1.8x106 kg = 1800 tons  

    So, considering the efficiency of the Power plant equals to 100%, approximately 1800 tons of coal per day is necessary.

    The efficiency of coal is 31%, so 5806.45 tons of coal per day is necessary to produce 500 MW-day.

 

    58% of carbon → 3367.7 tons of carbon / 500 MW

    3% of sulfur → 174.2 tons of sulfur / 500 MW

Natural Gas (CH4 + O2 → CO2 + H2O)

1 kg of natural gas → 6.02x10-4 MW-day

            x kg of natural gas → 500 MW ,  x = 0.83x106 kg = 830 tons  

    So, considering the efficiency of the Power plant equals to 100%, approximately 830 tons of natural gas per day is necessary.

    The efficiency of coal is 45%, so 1845.7 tons of natural gas per day is necessary to produce 500 MW-day.

    1% of the natural gas leaks: 0.1 * 1845.7 tons = 184.57 tons of carbon leaking to the atmosphere

    73% of carbon → 1347.36 tons of carbon   (+ 184.57 tons leaked) = 1531.93 tons of carbon / 500 MW                                

    0.5% of sulfur → 9.23 tons of sulfur / 500 MW

	Amount of fuel to produce 500 MW (tons)	Amount of CO2 emitted to the atmosphere to produce 500 MW (tons)	Amount of SO2 emitted to the atmosphere to produce 500 MW (tons)
Coal	5806.45	3367.7	174.2
Natural Gas	1845.7	1531.93	9.23

     The amount of SO2 and CO2 emitted by the natural gas is lower than the amount emitted by the coal. Also, to produce the same amount of energy (500 MW) is necessary to use more coal than natural gas. To conclude, the natural gas is a better option than the coal.

      3.   1) The functional unit for the study is “the delivery of 1 kg of hot standard carcass weight (HSCW) at the exit gate of the meat processing plant”.

The system boundary encompasses all on-site and upstream processes at the farm, feedlot, and whole processing plant, including transport between these sites.

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2) Quantitative LCI data for a typical meat processing plant were obtained from published industry data. For fuel and transport processes, Australian data sets were used. Data for wheat, barley, canola, hay, and mineral supplement production were taken from previous LCI work.