In charge of Prof. Stefania Moioli

The aim of the course is the study of those unit operations, mainly separations, that can be of interest in the field of power generation and in the oil & gas industry for students in Energy Engineering. After a first part dedicated to the study of the fundamentals (thermodynamics, material and energy balances), the student is provided with the elements necessary for the selection and sizing of the equipment where the separation takes place. The explained principles and methods are applied at first to simple problems in order to make them clear to students and then to case studies in the fields of power generation and oil & gas. In the end XTL processes and processes for the abatement of pollutants from combustion processes are described.

 

The course main topics are divided as follows:

• introduction. Description of the contents. Unit operations: definition, classifications, examples of application in the fields of power generation and of oil &gas.

• outline of non-ideal mixtures and chemical equilibrium. Ideal and non-ideal mixtures. Gamma/phi methods and phi/phi methods. Equations of state. Vapor-liquid, liquid-liquid and solid-liquid-vapor equilibria.

• energy and material balances. Analysis of selected schemes of process units in power generation plants and oil & gas industry, development of process flow diagrams with material and energy balances calculations.

• unit operations. Principles, applications, operating procedures and solution methods for the following unit operations:

• flash. Flash at constant temperature and pressure. Adiabatic operation. Application example in the case of non-ideal mixture.

• distillation. Standard distillation columns. Thermodynamic design of the distillation column: McCabe-Thiele method. Determination of the operating conditions: pressure at the condenser, optimum reflux ratio.

• absorption and stripping. Diluted solutions: Kremser equation. Concentrated solutions: calculation of the minimum solvent flowrate and of the number of ideal stages.

• liquid-liquid extraction. Fields of application. One stage operation, stages in cross flow and in counter current flow.

• adsorption. Adsorption isotherms. Material balances. The pressure swing adsorption (PSA): the sequence of operations, adsorption and regeneration, for a continuous process; equipment description.

• equilibrium-stage operations and rate-based operations: the equipment. Plate columns: sieve plates, valve plates, bubble cap plates; plate design; local, plate and column efficiency. Packed columns: random and structured packings; design of the packed column. Stable operating regions for plate and packed columns.

• processes XTL. Recall on oil refining (hydrotreating; the cycle of sulfur) and on the production routes of synthesis gas from carbon and natural gas (gasification, steam reforming, ATR). Purification of synthesis gas. Processes for the production of synthetic fuels and additives via synthesis gas conversion: methanol and higher alcohol synthesis, Fischer-Tropsch synthesis.

• processes for the abatement of pollutants from combustion processes. Abatement of nitrogen oxides, sulfur oxides, particulate matter, mercury from power plant flue gases: continuous processes (SCR and SNCR) and regenerative processes (SCONOX), Air Pollution Control Devices (FGD). Removal of nitrogen oxides, carbon monoxide, and unburned hydrocarbons from vehicle exhaust: the three-way catalyst, deNOx systems for lean combustion engines.

 

The course is divided into lessons (48 hours) and classroom exercises (32 hours).

The final evaluation of learning is obtained through a written test, composed by numerical problems on the main topics of the course, and an oral test.

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