Daily Question 2015.9.7 (EIA Discussion): 3 Wealth points for replies, plus 5 Wealth points for correct answers (single-choice question)
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This post was last edited by Zhang Xiaopeng on 2015-9-7 at 14:42. A central heating boiler is planned to be installed in a zone classified as Category 2 for environmental air quality in a northern city. The initial concentration of dust in the boiler’s exhaust gas is 1800 mg/Nm3. The emission standard for dust in such zones is 200 mg/Nm3, while the local standard is 80 mg/Nm3. To ensure that the dust concentration in the exhaust gas meets these standards, the efficiency of the dust collector required must be no less than ( ) A. 95.6% B. 93.3% C. 92.2% D. 88.9% Correct answer: A. Explanation: Dust removal efficiency, also known as “separation efficiency”. Technical indicators indicating the dust removal efficiency of the dust collector. It can be expressed in terms of the overall dust removal efficiency or the hierarchical dust removal efficiency. The overall dust removal efficiency refers to the percentage of dust captured by the dust collector within a given time compared to the amount of dust that enters it; it represents an average value indicating the degree of dust removal achieved by the system. (1800-80)/1800*100% = 93.6%. This question also tests another concept: when local standards exist, they should be given priority over other standards
A.93.6% should be 95.6%, right?
My answer was option C
A.93.6%..............
A central heating boiler is planned to be installed in a zone classified as Category II for environmental air quality in a northern city; the initial dust concentration in the boiler’s exhaust gases is 1800 mg/Nm3. To ensure that the exhaust gas dust concentration meets the regulatory requirements, the efficiency of the dust collector required must be no less than 88.9%. (1800-200)/1800*100%=88.9%
D, 88.9%---------------------------------------
A central heating boiler is planned to be installed in a zone classified as Category 2 for environmental air quality in a northern city; the initial dust concentration in the boiler’s exhaust gas is 1800 mg/Nm3. To ensure that the exhaust gas meets the emission standards, the efficiency of the dust collector required must be no less than (A). A.93.6% B.93.3% C.92.2% D.88.9%
A central heating boiler is planned to be installed in a zone classified as Category 2 for environmental air quality in a northern city; the initial dust concentration in the boiler’s exhaust gases is 1800 mg/Nm3. To ensure that the dust concentration in these exhaust gases meets the regulatory standards, the efficiency of the dust collector required must be no less than (D.88.9%). A.93.6% B.93.3% C.92.2% D.88.9%