Separation Processes I


The main purpose of Separation Processes I is to provide to students the ability to:

- Understand the fundamental concepts of equilibrium-controlled separation processes used in the chemical industry: gas/liquid absorption, distillation, liquid-liquid extraction, humidification, and drying.

- To design the equipment required for each of the studied processes.

General characterization





Responsible teacher

Isabel Maria Rola Coelhoso, Pedro Miguel Calado Simões


Weekly - 5

Total - Available soon

Teaching language



Available soon


1. Wankat, P.C.,"Equilibrium Staged Separations", Blackie Academic & Professional, Glasgow, UK, 1990.

2. Treybal, R.E., "Mass Transfer Operations" McGraw Hill Inc.,Tokyo, Japão, 1981.

3. Gomes de Azevedo, E., "Engenharia de Processos de Separação", IST Press, 2013 

4. Rousseau, R.W. “Handbook of Separation Process Technology”, Wiley 1987

Teaching method

The teaching comprises lectures and practical classes where the students will use ASPEN. Lectures cover all the content according with the syllabus. Wherever necessary example problems will be solved to illustrate the given concepts. Practical classes are programmed so that students, in the form of groups, will apply ASPEN to solve a series of separation processes exercises.

Evaluation method

Evaluation of the course consists of two components:

1. Two tests (closed-booked), each one worth 35% of the final grade. The first test covers gas absorption and Distillation. The second test encompasses the remaining chapters of Solvent Extraction, Humidification and Drying.

The duration of each test is 1 ½ hours. Each test is evaluated in a 0 to 20 scale. The evaluation is individually. It is required a minimum score of 10 (9.5) values in the arithmetic average of the grades of the two tests.

2. To perform and present a work (to be held in a group). To resolve a practical problem of a separation process using the ASPEN software tool. It accounts for 30% of the final grade. It is required a minimum score of 10 (9.5) values ​​in this evaluation component.

If the student did not succeed in the 1st component of the assessment (Achievement of two tests) or have chosen not to do it, she/he will have the right to go to final exam (“Exame de Recurso”). If the student have not passed the 1st component assessment, he/she can choose to do only the part corresponding to one of the tests, of his/her choice (they must inform the professors up to 48 hours before the exam date which test they want to repeat). The test grade will be replaced by the corresponding part of the exam. For the student who takes the final exam it is required a minimum score of 10 (9.5) values ​​in the final exam grade.

Regardless the student wants to opt for performing the two tests or go to final exam, it will always be mandatory the accomplishment of the 2nd component of the assessment of the course, that is, the group work in ASPEN.


Final grade: weighted average of the marks obtained in the two assessment components according to the following formula:

Final grade = 0.35 × grade of 1st Test + 0.35 × grade of 2nd Test + 0.30 × grade of ASPEN Work

The grades of the two tests and ASPEN work are rounded to one decimal. The final score, rounded to the nearest whole number, must be greater than or equal to 10 to be succeed in the discipline.

Subject matter

1. Liquid Extraction; Liquid – liquid equilibria; Criteria for solvent selection; Stagewise contact; Continuous contact equipment.

2. Gas Absorption. Equilibrium gas-liquid; Material balances; One component transferred; Countercurrent and cocurrent multistage operation; Continuous contact equipment; HOG and NOG; Criteria for design and operation of equipment.

3. Distillation. Vapour- liquid equilibria; Multistage tray towers- method of McCabe and Thiele; Feed line. Operation with reflux; Method of Ponchon-Savarit; Packed towers; Batch distillation.

4. Humidification; Equipment. Water-cooling towers.

5. Drying; Equilibrium and definitions; Batch drying. Rate and time of drying; Continuous drying. Equipment and applications

6. Introduction to computational tool Aspen +. Resolution of an exercise with a multicomponent distillation column and a solvent extraction column by using Aspen.