A high-pressure pipeline carries a hydrocarbon (not methane) in vapor form. You are concerned about the...

 

 

Transcribed Image Text:

A high-pressure pipeline carries a hydrocarbon (not methane) in vapor form. You are concerned about the safety of leaking hydrocarbon vapors from one of the flanges in the pipeline, since it is close to several workers. (a) Using emission factors provided on the course website, taken from the Heinsohn - Cimbala, estimate the emission rate in mg/hr using emission factors. Be careful of the units, and give your answer to one significant digit, since emission factors are typically good to at most one digit. (b) Suppose you conduct a test to measure the emission rate experimentally. You place a plastic bag around the flange, and blow clean air into it. You assume that the ambient air is clean. On the other end of the bag, air is withdrawn, and the concentration of the hydrocarbon is measured after it achieves steady-state conditions. When the air flow rate is 2.4 m 3/hr, c ss = 220 mg/m 3, and when the flow rate is 4.1 m 3/hr, c ss = 125 mg/m 3. Calculate the emission rate in mg/hr and compare to the value obtained in Part (a). Which do you trust more? Why? A high-pressure pipeline carries a hydrocarbon (not methane) in vapor form. You are concerned about the safety of leaking hydrocarbon vapors from one of the flanges in the pipeline, since it is close to several workers. (a) Using emission factors provided on the course website, taken from the Heinsohn - Cimbala, estimate the emission rate in mg/hr using emission factors. Be careful of the units, and give your answer to one significant digit, since emission factors are typically good to at most one digit. (b) Suppose you conduct a test to measure the emission rate experimentally. You place a plastic bag around the flange, and blow clean air into it. You assume that the ambient air is clean. On the other end of the bag, air is withdrawn, and the concentration of the hydrocarbon is measured after it achieves steady-state conditions. When the air flow rate is 2.4 m 3/hr, c ss = 220 mg/m 3, and when the flow rate is 4.1 m 3/hr, c ss = 125 mg/m 3. Calculate the emission rate in mg/hr and compare to the value obtained in Part (a). Which do you trust more? Why?