 # Heat and mass transfer

## Presentation

Program (detailed contents):
General equation for energy conservation. Application to heat transfer problems on different geometries without or with heat sources, in steady or unsteady state.
Heat losses through plane, cylindrical surfaces, cooling fins, temperature profile in a catalytic reactor and a single phase reactor.
Heat transfer in a reaction vessel with helical cooling coil or jacketed vessel: heating or cooling time.
Case studies: reactors, heat exchanger
Thermodynamic properties of the gas liquid equilibrium for ideal gas state. Transfer properties (viscosity, thermal conductivity, molecular diffusion in fluids) and phase equilibria of multi-real fluid constituents. Physical equilibria of binary systems.

Introduction to mass transfer: establishment of the continuity equation, solving this equation in some special cases. Introduction of the concept of transfer coefficient: dimensional analysis, transfer models (film and double film), experimental determination of transfer coefficient; introduction to the concept of Height Transfer Unit (HTU) and Number of Transfer Unit (NTU). Introduction to the basic design of some exchangers G/L (packed towers, bubble column, scrubbers).

Organisation:
Lectures where the fundamental notions are highlighted, followed by tutorial exercises, where students work together in little groups, on issues which illustrate and apply the presented concepts. A frame constituted of problems with elements of answer is given to the students in order to guide their personal work.

Documents:
Duplicated lecture notes and tutorial exercises, including the personal works. Three books written by the teaching staff are available from the library of the establishment.
One book is lent to the students for 1 semester:
Roustan M., Transferts gaz-liquide dans les procédés de traitement des eaux et d’effluents gazeux, Editions TEC & DOC, 2003.

## Objectives

At the end of this module, the student will have understood and be able to explain (main concepts):
- general equation for energy conservation
- conduction (Fourier’s law)
- convection (forced and natural)

At the end of this module, the student will be able to write and use the thermodynamic equations leading to enthalpy, entropy and fugacity determination in multiphase fluid systems. These thermodynamic concepts will be applied to calculate the potential exchange and mass transfer properties usually considered to model and solve mass transfer unit operation.
Students will understand the notion of mass transfer coefficient, and will be able to estimate this coefficient in a particular application.
At the end, the student will be able to write and solve the mass balance corresponding to industrial gas/liquid contactors as bubble columns, scrubbers or packing towers.

The student will be able to:
- establish and solve energy balances on systems with or without reactions
- calculate heat losses through laggings
-  characterize heat transfer in fins
- characterize the temperature gradient in a catalytic reactor and a single phase reactor
- calculate the time of heating/cooling of a reactor
- solve case studies relative to processes (reactors, heat exchangers…) or/and to buildings (solar captors, double glazing…)

## Needed prerequisite

Transport phenomena in fluids
Thermodynamics : fundamentals and application to phases equilibria (I2BETH11)
Fluid properties (I3BEPF12)

## Form of assessment

The evaluation of outcome prior learning is made as a continuous training during the semester. According ot the teaching, the assessment will be different: as a written exam, an oral exam, a record, a written report, peers review...