【Daily Question】Question from Issue 20150929
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Participation reward: 2 Wealth. Reward for correct answer: 9 wealth. In the gas space of an oil storage tank, during nighttime storage at rest, the dominant mode of oil vapor mass transfer is ( ). A. Molecular diffusion B. Thermal diffusion C. Forced convection D. Mutual fusion 【Production and Management Division】Seeking moderators and technical discussants to join
In the gas space of an oil storage tank, during static storage at night, the dominant mode of oil vapor mass transfer is (A). A. Molecular diffusion B. Thermal diffusion C. Forced convection D. Mutual fusion
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In the gas space of an oil storage tank, during stationary storage at night, the dominant mode of oil vapor mass transfer is (A. molecular diffusion). A. Molecular diffusion B. Thermal diffusion C. Forced convection D. Mutual fusion
In the gas space of an oil storage tank, during static storage at night, the dominant mode of oil vapor mass transfer is (B).
In the gas space of an oil storage tank, during static storage at night, the dominant mode of oil vapor mass transfer is (A). A. Molecular diffusion
The answer is B. In the case of a stationary storage tank, the transfer of oil vapor at night – molecular diffusion and mixing – is not considered a process of mass transfer. Forced convection occurs when there is medium flow or when external air passes over the surface; what matters here is flow. At night, due to temperature changes, the temperature decreases from daytime to midnight, and then increases from midnight to morning. The upper space of the storage tank is affected by these temperature changes, resulting in dynamic changes between gas and liquid; this is what is known as heat diffusion.
B. Thermal diffusion – – – – – – – – – – – – – – – – – – –