Note: Real exam questions from 2011, Knowledge section, Morning session, Question 47
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47. Which of the following unit operations do not involve heat transfer? A. Solid fluidization B. Heating and cooling C. Stirring D. Sedimentation. I’ve read quite a few posts as well; AD definitely don’t fit. Is there any heat transfer when stirring? I’m sorry to bother everyone
47. Which of the following unit operations do not involve heat transfer? A. Solid fluidization B. Heating and cooling C. Stirring D. Sedimentation ACD
In 47 AD, mixing involves heat transfer! The mixing process is accompanied by changes in heat!
Take a look at this, Question 47 from the morning session on specialized knowledge in 2011: http://bbs.hcbbs.com/thread-1331161-1-22.html
Agreed. Regarding whether heat transfer occurs during mixing, refer to page 411 of the fourth edition of the Chemical Process Design Manual; the purpose of mixing is to achieve mixing, mass transfer, heat transfer, or carry out a reaction process! I still remember from middle school physics that stirring the hot water in a bowl can help it cool down faster. Hehe
xuanAD: Mixing involves heat transfer, so AD is chosen