Heat exchangers with or without phase transition and simultaneous heat and mass transfer

Presentation

Programme (detailed contents):

*TEMA standards, multi-tubular, plate exchangers, stirred vessels, condensers, boilers, evaporators (software Aspen HTFS), and their utilisation. Parallel, counter current, cross-flow, multi-pass heat exchanger

* Design procedure

Local and overall heat transfer coefficients, exchange area, logarithmic mean temperature difference LMTD. Pressure drop.

Efficiency. Different exchanger geometries will be considered.

*Condensation, application to the design of industrial condensers of different types of vapour mixtures.

*Boiling, evaporation, multiple effects evaporators

*Unit operations involving simultaneous mass and heat transfer:  design of a cooling tower, dehumidification tower, air conditioner, extension to systems using other vapour than steam. Drying, design of dryers.

Organisation:

Lectures, tutorials and lab-work.

Objectives

At the end of this module, the student will have understood and be able to explain (main concepts):

- the different types of heat exchangers, condenser, evaporators and other contactors carrying out both heat and mass transfer (cooling tower, humidification-dehumidification process,  air conditioning systems, drying equipments,..)

-  the mass and heat transfer mechanisms in these equipments

- the notion of efficiency

- film-wise and drop-wise condensation, the characteristics of the condensation of single or mixed  vapours with or without incondensable compounds

- the different mechanisms of boiling

- the concept of local coefficient and overall heat transfer coefficient

- the concept of simultaneous mass/heat transfer and their application to engineering especially for handling the system Air/Water/Steam

The student will be able to:

- select the adequate technology of the heat exchanger depending on the process requirement

- establish mass and energy balances on heat exchanger (continuous or batch, with or without phase change)

- establish simultaneous mass and energy balances

- design exchangers of all type: determine the local and overall transfer coefficient, evaluate its performance and its variation with a change of operating conditions

- use software such as ASPEN HTFS to design the heat exchanger

- design unit operations involving simultaneous transfers, such as cooling tower, dehumidification tower, air conditioners, dryers.

- provide basic elements useful for the design of furnaces

Needed prerequisite

Thermal transfers and reactors

Fluid properties and mass transfer

Thermodynamics

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...