The Hong Kong University of Science and Technology
Introduction to Chemical and Biomolecular Engineering
CENG 1000

Fall 2014
Example (heat of reaction)
N2(g) + 3H2(g) > 2NH3(g) Ar(400C) = 109 kI/mol
Our reactor is maintained at 400 C throughout. If the feed rates are 1 mol/s N2 and 3 mol/s H2, and
NH3 is produced at 0.3 moi/s, calculate the cooling load (in kJ/s) needed to main
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
11.69
11.69
11.69
11.69
PROBLEM 11.70
Air
120 m/s
1 atm
100oC
Air
Tmax
p
Q
At the inlet: ci =
kRT =
1.4 287 N m / kg K 373.15K =
N m / kg K =
387.2m / s
Ma i =
Vi
T
120m / s
373.15K
=
= 0.301 = 0.9822 T0i =
= 379.9 K
ci 387.2m / s
T0
0.9822
The mass flow
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
12.29
12.29
PROBLEM 12.30
Given Prototype fan; D = 20 ft, p in = 14.40 psia, T in = 70oF, = 90 rpm
1/10 scale model, same p in and T in , W shaft = 1.24 hp, Q = 220 cfm, = 1800 rpm
Find Power and flowrate of prototype fan
Solution
The scaling law for powe
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
PROBLEM 12.22
12.22
PROBLEM 12.22
The Reynolds number is,
Re
Re
factor f = 0.02 for the pipe, and all minor losses, except for the valve,
are negligible. The fluid levels in the two tanks can be assumed to
remain constant.
(a) Determine the flowrate with
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
PROBLEM 12.68
+
+
=
PROBLEM 12.69
12.69
+
PROBLEM 12.69
PROBLEM 12.70
12.70 The figure below shows a nozzle vane and a rotor blade for an axial flow gas turbine stage.
The blade speed is 800 ft/s. The absolute velocity leaving the stage is identical to t
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
PROBLEM 11.72
11.72 Air is stored in a tank where the pressure is 40 psia and the temperature is 500 R. A
convergingdiverging nozzle with an exit tothroat area ratio of 2.5 attaches the tank to a duct
where heat is exchanged with the air. The exit press
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
Problem 12.58
Water flows through the Pelton wheel turbine shown in Fig. 12.25. For simplicity we assume
that the water is turned 180 by the blade. Show, based on the energy equation (Eq. 5.84), that
the maximum power output occurs when the absolute veloc
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
12.64
12.64
12.64
12.65
Obtain photographs/images of a variety of turbocompressor
rotors and categorize them as axialflow or radialflow compressors.
Explain briefly how they are used. Note any unusual features.
Repeat for compressible flow turbines.
Th
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
12.34
Draw a sketch of the pump impeller
(front and side views).
The sketch should be similar to Figure P12.52.
12.35
Draw a sketch of the pump impeller
(front and side views).
The sketch should be similar to Ns = 2.0 impeller in Figure 12.18.
PROBLEM 12.
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
PROBLEM 12.42
Re
Re
Re
PROBLEM 12.43
12.43 A model fan with wheel diameter 32 in. is tested at a speed of 1750 rpm. The test fluid is
air with density 0.075 lbm/ft3. At its BEP, the fan produces 8000 ft3/min at total pressure rise of
8 in.H 2 O. A geometr
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
PROBLEM 12.24
12.25
Water is pumped between the two tanks described in
Example 12.4 once a day, 365 days a year, with each pumping
period lasting two hours. The water levels in the two tanks remain
essentially constant. Estimate the annual cost of the ele
The Hong Kong University of Science and Technology
Process Fluid Mechanics
CENG 2220

Spring 2015
PROBLEM 12.38
12.39
For the fan of both Examples 5.19 and 5.28 discuss what fluid
flow properties you would need to measure to estimate fan efficiency.
This is an openended student activity for which student responses will vary. No Solution is
available.
The Hong Kong University of Science and Technology
CENG 1700

Fall 2007
CENG1700  Introduction to Environmental Engineering
Assignment 1
1
A 6M hydrochloric acid (HCl) has a density of 1.098 kg/L at 20 C, please show the concentration of HCl
in water in term of kg HCl/kg. (MW: H=1 g/mol; Cl=35.5 g/mol) [10m]
Assume the volum
The Hong Kong University of Science and Technology
Heat and Mass Transfer
CENG 3220

Spring 2016
Chapter 5: Isothermal Reactor
5.1 Mole Balances in terms of Conversion
5.2 Pressure drop in PBR
5.2 Membrane reactor and Semibatch reactor
5.1 Mole Balances in terms of Conversion
Algorithm for Isothermal Reactor Design
1. Mole Balances and Design Equatio
The Hong Kong University of Science and Technology
Heat and Mass Transfer
CENG 3220

Spring 2016
Chapter 3: Rate Laws and Stoichiometry
3.1 Rate Laws
3.2 Stoichiometry in batch & flow systems
Review Chapter 1
Reactor Mole Balances Summary
The equations apply to the four major reactor types (and the general
reaction AB)
Reactor
Differential
Algebraic
The Hong Kong University of Science and Technology
Heat and Mass Transfer
CENG 3220

Spring 2016
Chapter 4: Analysis of Rate Data
Determining the Rate Law from Experimental Data
1) Integral Method
2) Differential (Graphical, Polynomial) Method
1). Integral Method
Consider the following reaction that occurs in a constant
volume Batch Reactor: (We will
The Hong Kong University of Science and Technology
Heat and Mass Transfer
CENG 3220

Spring 2016
Quiz 1A: Mole balances and Reactor sizing
Student Name: _
Student No.: _
Full marks: 50. Duration: 45 min. Necessary data may be found from lecture notes.
1. Multiple choices (Circle the right answer):
(10 marks)
1). Which equation is used in arriving at
The Hong Kong University of Science and Technology
Heat and Mass Transfer
CENG 3220

Spring 2016
CENG 3230
Reaction and Reactor Engineering
Instructor:
Yuan Shuai LIU, Marshal
Tel: 23588409
keysliu@ust.hk
1
Office: 4551
Course Learning outcomes
Upon the completion of this subject, students will be able to
(1) Understand the basic principles of react
The Hong Kong University of Science and Technology
Heat and Mass Transfer
CENG 3220

Spring 2016
Chapter 6 Multiple reactions
6.1 Reaction in series
6.2 Complex reactions
1
4 Types of Multiple Reactions
Series:
ABC
Parallel:
AD
AU
Independent:
AB
CD
Complex:
A + B C + D
A+CE
With multiple reactors, either molar flow or number of moles
must be use
The Hong Kong University of Science and Technology
Heat and Mass Transfer
CENG 3220

Spring 2016
Chapt 7 Reaction mechanism and
Bioreaction
7.1 Active Intermediates and Nonelementary Rate laws
7.2 Enzymatic reaction
7.3 Bioreactors
7.1 Active Intermediates & Nonelementary Rate laws
Example
The rate law for the reaction
A BC
is found from experiment t