The trainee will be included in the research activities of the Plant and Process Research Group of the Generation Technologies and Materials Department on the topic of biological methanation.

Research topic:

By methanation of CO2 we mean the synthesis of methane starting from CO2 and H2. In particular, we intend to refer to a biological methanation process, particularly suitable for biogas upgrading. The synthesis of methane is promoted by microorganisms of the Archaea domain, according to one of the ways in which it occurs inside the anaerobic digesters and can take place either directly in situ, in the anaerobic digester, by injection of hydrogen (CO2 is that of biogas) or in a separate reactor (ex-situ), fueled by biogas and hydrogen. Always in the presence of water.

All the literature highlights that the major obstacle to efficient methanation, whether carried out in situ or ex situ, is the gas / liquid mass transfer, in particular hydrogen, characterized by very low solubility in water. Inside the methanation reactor we always have to deal with a three-phase system in which the gas, to reach the microorganisms, must be able to diffuse into the liquid.

The technological choices to improve mass transfer are mainly addressed to:

guarantee a better distribution of the gas in the liquid by relying, for example, on efficient mixing systems and efficient distributors (as in CSTR reactors);
increase the times and the contact surface between the gas and the liquid by creating, for example, reactors sufficiently developed in height, with the gas injected from the bottom, equipped with recirculation or filling structures that make the gas path tortuous, perfecting systems that produce small bubbles, with the double advantage of also reducing the ascent rates;
reduce the thickness of the liquid that the gas must pass through to reach the microorganisms, using trickle-bed reactors, in which the culture liquid of the microorganisms is reduced to a film deposited on supports, kept suitably humidified.

Activities:

The activity carried out by RSE on the subject of biomethanation is focused on the study of trickle bed systems. These are reactors typically characterized by a high height / diameter ratio, inside which are contained plastic filling materials characterized by a high surface to volume ratio. The water is inserted in the upper part of the reactor, through one or more nozzles in quantities and with flows sufficient to guarantee the formation of a liquid film on all surfaces, in order to promote the growth of biofilm and ensure suitable living conditions for the microorganisms.

Specifically, the trainee alongside expert personnel will be included in the numerical modeling of trickle bed reactors: in particular, he will deal with describing the complex hydrodynamic phenomena, the diffusion of gases in the liquid and the kinetics of biological reactions, in order to produce a useful tool both as an integration to experimentation (through which, among other things, validation will be carried out) and for the design of new reactor and process configurations.

Minimum requirements (Technical knowledge / Exams / Skills and aptitudes)

The intern must have completed all the exams before the start of the internship in the company.

It also requires:

a good knowledge of fluid dynamics and mass transport phenomena and operational autonomy in the use of modeling tools.
an advanced knowledge of the Italian language (written and oral).
an average of exams above 26 (first level and master’s).
a good predisposition to team work and a fair degree of autonomy in the organization and management of work.

Educational qualification (and any specializations / Masters, etc.)

Five-year undergraduate in Energy Engineering, Environmental Engineering, Chemical Engineering, Mechanical Engineering, Biomedical Engineering.

Place of work: Milan

Reimbursement of expenses / internship compensation: NO

Company canteen: YES