Structured packing

Our Propak^тм structured packing in compliance with TUU 29.2-30895845-005:2010 (type Mellapak) for columns are used in separation and heat-mass exchange processes (distillation, rectification, absorption, desorption). Structurally, the packing is made of vertically placed corrugated metal plates (foil) or woven meshes with corrugations angle, step and height according to the required specific surface of layer contact in order to create open cells with tipping channels, see Table 1.

To facilitate the installation process, the packing is manufactured in the form of blocks depending on the apparatus structure and access hole diameter. When manufacturing the blocks, the corrugated plates are connected with the help of spot weld according to specific pattern. In order to equalize the pressure throughout the packing volume, the holes are made in metal plates, and in order to improve the wettability of the packing the metal plates are structured with fine corrugations in the form of cavities and peaks.

Propak^тм structured packing produced depends on the materials used:

• Propak^тм М series – smooth metal plate is used
  
• Propak^тм R series – metal plates are structured with fine corrugations in the form of cavities and peaks.
  
• Propak^тм PF series – perforated plate.
  
• Propak^тм P series – expanded steel plate.
  
• Propak^тм S series – metal woven mesh is used.
  

Propak^тмpacking blocks are laid on support grids that have holes and gaps for gas flow and liquid run-off. The latter uniformly moistens packing elements with the help of distributor and flows down. The uniform liquid distribution throughout the whole packing layer height across the column section is usually not achieved, which can be explained by the wall effect – the density of packing laying is higher in the central part of the column than near the walls. As a result, the liquid tends to spread from the central part of the column to its walls. Therefore, in order to improve the wettability of the packing in columns with large diameter, the packing is sometimes laid by layers (sections) 1-3 m high, and the liquid redistributor is installed under each section except for the bottom one.

Due to the irregular shape of the Propak^тм, packing surface, the liquid within the column flows along the element of the packing mainly in the form of a thin film, therefore, the phase contact surface is mainly represented by the wetted packing surface. The liquid film flows along the packing element. When the liquid flows from one packing element to another, the liquid film is destroyed, and the new one appears in the lower element. At the same time some portion of liquid goes through the lower layers of packing in the form of trickles, drops and drips. Some part of the packing surface may be wetted with stationary (stagnant) liquid.

The basic characteristics of packing are its specific surface (м²/м³) and free volume (м³/м³). Our Propak^тмpacking efficiently operates under excess and atmospheric pressure, as well as in vacuum conditions.

Specific structure of packing surface formed by cavities and peaks improves the wettability and distribution uniformity, stimulates dispersion and regeneration of liquid film, and increases the mass transfer coefficient.

Moreover, the specific shape of our Propak^тм packing improves the rigidity of packing structure. As compared to regular structured packing, the efficiency is increased by 10%-15% %, and the production capacity is improved by 10%.

Distinctive features:

- Hydraulic resistance of 1 theoretical separation stage 0,3 - 1,0 mbar
- Hydraulic resistance under 70-80% load of flooding rate ~ 0,2 mbar/m
- Minimum liquid load ~ 0,2 m³/m²h
- Maximum liquid load - over 200³/m²h.

Owing to these advantages and distinctive features, our Propak ^тм structured packing is not worse and. In some cases, even better than the Mellapak, Sepak structured packing produced by Sulzer Chemtech Ltd, and other companies.