109年 - 109中原大學_碩士班招生考試_化學工程學系︰輸送現象及單元操作#101441

(b) Recycle stream with a purge in a chemical process (Draw a scheme to explain)

(d) The Sherwood Number for mass transfer

Problem 2
A well-known real gas law is the van der Waals equation, which is written as

where
P = pressure, in atm
= molar volume, m³/mole
R = ideal gas constant
T = temperature
What are the units of a and b?

Problem 3 In typical semiconductor manufacturing processes, for instances, chemical vapor deposition (CVD), etching, ion implantation and epitaxy, there are usually several sorts of toxic gases generated, such as AsH3, SiH4, PH3, B2H6 and SiH2Cl2. The absorption tower is one of the general equipment adopted to remove these gases. The most popular absorbents to fill the tower are active coal, silica, aluminum hydroxide gel, or zeolite. To improve the flow behavior, steam is usually injected alongside the toxic gases. In such a gas removal unit, a flux of 100kg toxic gases-steam mixture with a concentration of 43% gases (wt%) is treated per day and lowered down to a 5% outlet stream. How long can the absorption tower last until a need to switch from Tower B to the other flash and ready-to-use Tower A, if a batch of the absorbent’s absorption capacity is 153kg of toxic gases. 43% gases 5% gases 57% steam 95% steam 100 kg/day P kg/day Tower A B Step (1) 153 kg gases Fresh (3) absorbents absorbed loading Shut down and discharge absorbents (2) Running absorption

Problem 4

A sphere

is freely settling in a liquid (density=ρ, viscosity=γ). Assume the Reynolds number is very small. Please start from the force analysis of the sphere and derive the equation of terminal velocity.

(a) Find the Reynolds number of the flow in the pipe.

(b) What is the pressure PA required? 15 m Nitrogen Tank 2 PA Sulfuric acid Tank 1

(1) Stoke’s law:

(2) Hagen-Poiseuille equation:

(3) Ergun equation:

(4) Mechanical-energy-balance equation:

(5) Fourier’s law:

109年 - 109中原大學_碩士班招生考試_化學工程學系︰輸送現象及單元操作#101441

試卷資訊

選擇題 (0)

申論題 (15)