SPIN Centre for Chemical Engineering

Crystallization

The research lines in crystallization are:

  • The understanding and description of crystallization phenomena, from the thermodynamics of species and the kinetics of nucleation, growth, agglomeration and breakage
  • The characterization of the macro mixture and micro-mixture according to the geometry of the reactor, its mode of operation, the stirring speed or the type of flow. These phenomena impact the local compositions (supersaturation) and therefore the granulometry of the obtained solids
  • The modeling of the crystallization in agitated reactor and in flow with the coupling between the kinetics, the transfers of energy and mass and the mechanics of the fluids

This knowledge is applied to minerals precipitation or solids dissolution-recrystallization as well as to gas hydrates and clathrates for applications in air conditioning, CO2 capture, water treatment and flow assurance in off shore petroleum transport.

Experimental facilities Models

  

Experimental facilities (reactors and instruments)

We operate multi-instrumented crystallization reactors, ranging from liter-scale up to semi-industrial pilot. The semi-industrial studies are supported by a team of design, development and fabrication of instrumented prototypes and by a mechanical workshop. The instrumentation means for monitoring the phenomena are online: two microscopes, a FBRM probe, two gas chromatographs, a fast camera, a Raman microscope and an ATR-IR probe.

From left to right, the picture above shows our equipments:

  • Bubble column (50 L) for CO2 capture (5 atm, 12°C) trough gas hydrates formation
  • 1 to 6 liter reactors at low and high pressure to study the thermodynamics and kinetics of crystallization. The high pressure reactors are equipped with in line gas chromatographs and Raman probe. Atmospheric reactors are equipped with conductivity probes, ATR-IR, microscopic endoscope
  • Air conditioning system using phase change materials : home design and manufacturing, storage of cold (Patm, 12°C) 2 tons of a solution of tetra butyl ammonium bromide (TBAB), air conditioning of 600 m2
  • Flow loop which simulates the petroleum transport between an off-shore well and a platform (80 atm, 4°C, 5 m long, 12 m high) equipped with FBRM, PVM, acoustic emission, permittivity, flowmeter and densimeter and pressure drop probes

  

Models

The study of crystallization begins with experimental work in which the topology and kinetics of crystallization, namely nucleation, growth, agglomeration and breakage; are determined according to the operating parameters. At the same time, thermodynamic and chemical balances as well as mass, energy and momentum transfers are studied. The modeling of the crystallization is thus the coupling of these three phenomena and depends on a large number of parameters and properties. We make use of two softwares: GasHyDyn_0D for the crystallization thermodynamics of clathrates hydrates and
ARXIM_0D for the speciation during mineral precipitation.

 
The picture above shows the topology of crystallization from an initial state of dispersion, which induces the growth site of methane hydrate (in white in the figure) and thus the size of the crystals, from an oil system (in yellow) and water (in blue) during flow.

 

Group members