An alkaline absorption system is used to reduce carbon dioxide concentration in a gas stream from 10% to 0.1% via an irreversible chemical reaction. What is the overall number of transfer units evaluated on the gas phase ?
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Answer: B. 4.605
Explanation
Overall gas-phase transfer units measure the difficulty of mass transfer operations. For irreversible absorption, the transfer unit count equals the natural logarithm of concentration ratios. Calculating natural log of zero point one divided by zero point zero zero one yields four point six zero five. Irreversible chemical reactions drive interfacial concentration differences to near zero. Natural logarithms of inlet and outlet mole fractions determine transfer unit heights. Packed column heights equal the height of a transfer unit multiplied by the number of units.
Alkaline scrubbers efficiently remove carbon dioxide from gas streams in chemical plants. Design engineers use transfer units to calculate required packing heights for gas absorption. Irreversible reaction kinetics maximize mass transfer rates in industrial packed towers. Option A represents double the correct transfer unit value due to calculation errors. Option C incorrectly uses a linear concentration difference rather than logarithmic ratios. Option D confuses fractional concentrations with transfer unit calculations.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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