# TRANSFER PROCESSES - 2018/9

Module code: ENG2109

Module Overview

Mass Transfer: Mass transfer is essential knowledge for chemical engineers, governing the underlying operations in many industrial processes involving, for example, separation and reaction. The purpose of the module is to introduce students to mechanistic and semi-empirical descriptions of mass transfer, and to apply such understanding to the design of process such as gas absorption and drying.

Fluid mechanics: The main part of the syllabus concentrates on developing the student’s understanding of internal flows. Knowledge of turbulent flow is extended by the introduction of the Universal Velocity Profile. Furthermore, more complex flows, which may include multiple phases or compressibility, are introduced.  The issues of drag and terminal velocity of particles is tackled and the features and flow of some non-Newtonian fluids discussed.

A short introduction is given on the simulation of real-life Mass-Transfer and Fluid Mechanics problems using commercial software.

Module provider

Chemical and Process Engineering

HARE C Dr (Chm Proc Eng)

Number of Credits: 15

ECTS Credits: 7.5

Framework: FHEQ Level 5

JACs code: H800

Module cap (Maximum number of students): N/A

Module Availability

Semester 2

Prerequisites / Co-requisites

Completion of the progression requirements to FHEQ Level 5 of the degree courses in Chemical Engineering, Chemical and Bio-Systems Engineering and Chemical and Petroleum Engineering, or equivalent.

Module content

Indicative content includes:

Mass Transfer

Introduction to mass transfer

Molecular diffusion: Fick's law
General case of diffusion with bulk (convective) flow
Stefan's law
Diffusivity determination and prediction
Mass transfer coefficients; mass transfer correlations
Momentum, heat and mass transfer analogies; J-factor analogy

Mass transfer across interfaces

Whitman two-film theory
Gas-liquid equilibria; Henry's law
Overall driving force and overall mass transfer coefficients
Film control and design implications

Absorber and stripper design

Industrial processes: staged vs. continuous contact equipment
Absorber / stripper design equations: height and number of gas-transfer units; graphical and analytical solutions
Other contact configurations: well-mixed flow; co-current flow; extension of concepts to liquid-liquid systems

Diffusion in solids

Pore diffusion: molecular, Knudsen, configurational
Effective diffusivity
Diffusion through non-porous solids; membranes

Drying of particulate solids

Mechanisms of drying
Drying rate curves
Kinetics of drying
Drying equipment
Characterisation of wet gas streams: humidity definitions; humid heat; enthalpy; humid volume; adiabatic saturation and wet-bulb temperatures; psychrometric ratio; psychrometric charts

Fluid Mechanics

Turbulent flow in a pipe

Revision of 1/7th power law
The universal velocity profile.
Eddy viscosity and its link to eddy diffusivity
Mixing of fluids

Two phase gas-liquid flow in pipes

Flow pattern maps in horizontal and vertical flow
Pressure differences (incl. Method of Lockhart and Martinelli)

Equipment for pumping gases

Types and their characteristics
Reminder of inter-cooling
Surge and recycle

Compressible flow of gases

Reminder of basic equations (Continuity, Ideal Gas law, adiabatic equations, steady flow energy equation)
Isothermal compressible flow in pipelines (density changes, speed of sound, choking)
Isentropic compressible flow through valves (density changes, speed of sound, choking, existence of shock waves). How to predict whether a valve is choked. Calculation of relief valve capacity
When is a flow likely to be isothermal or isentropic? Mention of polytropic flows.
Brief discussion of convergent-divergent nozzles.

Terminal velocity

Drag coefficients for a sphere
Force balance for a sphere in free fall
Equations for terminal velocity

Non-Newtonian Fluids including Colloids

Types of non-Newtonian behaviour
Van der Waals’ forces and colloidal rheology
Internal flow of non-Newtonian fluids

Assessment pattern

Assessment type Unit of assessment Weighting
Examination EXAMINATION (2 HOURS) 80
Coursework COURSEWORK 20

Alternative Assessment

N/A

Assessment Strategy

The assessment strategy is designed to provide students with the opportunity to demonstrate the full range of learning outcomes though the balanced mixture of lecture and tutorial/problem classes coupled with the carefully graded tutorial problems which reflect current industrial practice.

Thus, the summative assessment for this module consists of:

Examination – 80% (weighted 48% to Mass Transfer and 32% to Fluid Mechanics), 2 hours (LO1 – LO9)
Coursework – 20% (Mass Transfer). Absorption column design calculations (LO2).

Formative assessment

Mass transfer class test (LO1, LO2, LO4, LO5)
Randomised multiple choice tests on SurreyLearn (LO6, LO7, LO8)

Feedback

Weekly verbal feedback during tutorial classes (LO1 – LO9)
Written feedback on Coursework (LO2)
Verbal feedback at the end of the formative class tests (LO1, LO2, LO4, LO5)

Module aims

• Introduce the key concepts of mass transfer operations in Chemical Engineering, with a specific focus on gas-liquid and gas-solid systems.
• Provide the knowledge and skills to undertake the specification and design of absorption columns (i.e. continuous diffusional contact devices).
• Provide an introduction to the selection and design of solids drying equipment.
• Provide students further and deeper understanding of fluid flows in Chemical Engineering.

Learning outcomes

Attributes Developed
001 Describe the key principles of, and modelling approaches to, mass transfer in fluid-fluid and fluid-solid system. KC
002 Design absorption and stripping equipment based on continuous diffusional contact. KCP
003 Develop general mathematical models for mass transfer in different phase-contact and phase-flow situations. KC
004 Describe the drying mechanisms of particulate solids and the classification of drying operations. KC
005 Analyse batch and continuous drying operations. KCP
006 Explain the physics behind turbulent flow in a pipe and how that affects the velocity profile, the fluid friction at a pipe wall KC
007 Explain the physics behind non-Newtonian flows, describe the most common rheological models and describe colloidal suspensions KC
008 Describe the key steps involved in setting up a numerical simulation of real-life Mass-Transfer and Fluid Mechanics problems using commercial software. KP

Attributes Developed

C - Cognitive/analytical

K - Subject knowledge

T - Transferable skills

P - Professional/Practical skills

Independent Study Hours: 106

Lecture Hours: 33

Tutorial Hours: 11

Methods of Teaching / Learning

The learning and teaching strategy is designed to:

Carefully cover in lectures the necessary fundamental material and analytical techniques, and demonstrate concepts with appropriate (and where possible practical) examples
Allow students adequate time to practice the techniques using a large number of carefully selected tutorial problems.

The learning and teaching methods include:

Lectures                                  3 hours per week for 11 weeks
Tutorial/Problem Classes         1 hour per week for 11 weeks
Independent learning                8 hours per week for 12 weeks (average)

Indicated Lecture Hours (which may also include seminars, tutorials, workshops and other contact time) are approximate and may include in-class tests where one or more of these are an assessment on the module. In-class tests are scheduled/organised separately to taught content and will be published on to student personal timetables, where they apply to taken modules, as soon as they are finalised by central administration. This will usually be after the initial publication of the teaching timetable for the relevant semester.