Efficient thermal separation processes

Thermal separation processes such as rectification, distillation, absorption, desorption and extraction are central unit operations in chemical process industries. The vapor-liquid separation processes are very energy-intensive, since they involve multiple sequences of evaporation and condensation. Approximately 3 % of the world’s energy is consumed by thermal separation processes, while 40 % of the energy in process industries itself is used by distillation and rectification processes. Since the energy consumption scales linearly with the column capacity, it can reach up to 10 to 100 MW for industrial separation processes.

The energy- and resource-intensive thermal separation processes demand innovative optimization approaches to intensify the contact between involved fluidic phases, such as enhancement of turbulence in each phase as well as increase in interfacial area, to favor mass and heat transfer processes. Besides, effective vapor-liquid separation is crucial for reduction of auxiliary equipments needed to compensate for process design uncertainties. Any carry-over of droplets in the vapor phase (called entrainment) should be eliminated, as far as possible, to achieve the desired product specifications.

Experimental and theoretical investigations concerning fundamental transport phenomena on separation internals are essential for better understanding of thermal fluid separation. For example, column trays are subjected to fluid dynamics analyses for improved design and operation.

The ongoing research on separation processes comprises of following investigations:

Foto: Experimental and theoretical investigations of fluid dynamics and mass transfer in sandwich packings - logo ©Copyright: Torsten Berger

Fluid dynamics and mass transfer in sandwich packings

Within the scope of the DFG-funded project, the fluid dynamic behavior of sandwich packings is comprehensively studied at HZDR. For this purpose, experimental studies are carried out in a 100 mm dia­meter column operated with water and air in the counter-current mode. The ultrafast X-ray ­tomo­graphy permits noninvasive imaging of the complex and highly dynamic flow patterns inside the packing.
Foto: Droplet formation and reduction in thermal separation devices - logo ©Copyright: Torsten Berger

Droplet formation and reduction in thermal se­paration devices

Droplet formation at specific positions in se­paration columns and the entrained by the vapor phase drastically reduce the se­paration capacity of columns. Core of the investigations at HZDR within the joint project ‘TERESA’ is the characterization of flow regimes and evolving droplet spectra in feed pipes with flash evaporation.
Foto: Effect of fluid dynamics on separation efficiency of column trays - logo ©Copyright: Dr. Markus Schubert

Fluid dynamics and se­paration efficiency of column trays

Flow and mixing patterns are studied at high spatial and temporal resolution via advanced measurement and imaging techniques in tray columns. A column fitted with sieve trays and a wire-mesh sensor is installed and hydraulic data are utilized to develop new modeling methodo­logies to quantify the tray se­paration efficiency.

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Dr. Markus Schubert
Experimental Thermal Fluid Dynamics
Phone: +49 351 260 2627
Fax: +49 351 260 2383

Prof. Dr. Uwe Hampel
Phone: +49 351 260 2772
Fax: +49 351 260 12772, +49 351 260 2383