Gas scrubber internals (tower packing - structured and random, droplet separators, demisters) for industrial emission treatment (air pollution control and odour control)
Tower Packing (structured and random)
Tower packing is used in lots of applications. Packed columns are most frequently used to remove contaminants from a gas stream (absorption). However, packed columns can also be used to remove volatile components from a liquid stream by contacting it with an inert gas (stripping). We will restrict ourselves here to these two applications (gas scrubbers and stripper-absorber combination), both in the field of air pollution and odour control and industrial waste water treatment.
Tower packing is a mass of inert, solid shapes to be inserted in a mainly cylindrical column. The purpose of tower packing is to create a bigger surface area for the gas and liquid transfert in a packed column (whether it is a gas scrubber or a stripper-absorber combination). A maximised surface area increases the exchange surface where gaseous components can be absorbed in the liquid (mass transfer). Tower packing materials combine a high surface area (maximum absorption area) with a low bulk density (to reduce obstruction risk of the packing).
Tower packing : various tapes
There are many different types of tower packing and tower fill materials. In general and depending on the application, this packing may be random or structured.
Structured packing are honeycomb (waffle, herringbone) block structures made of plastic or metal. The advantages of structured packings are the higher efficiency (lower Height of Transfert Units ), the efficient use made of available surface and lower pressure-drop they provide, compared to either random packings or trays. Structured packing is readily cut to measure to fit in the scrubber/absorber column (in several layers). Can also be built into cassettes for easy removal and cleaning.
Random packings (Pall rings, Raschig rings, saddle rings, etc.) are made of metal, plastic, ceramic. They are in general relatively inexpensive. The advantages are : high strenght, low weight, fouling resistance, easily interchangeable and cleanable. Metal or plastic random packing is most suitable for applications where the efficiency and pressure drop is not extremely important and in cases where the fouling risk is higher. Ceramic random packing is designed for applications demanding for a high temperature and/or high chemical resistance.
Demisters, droplet separators and other gas scrubber internals
A gas scrubber or air scrubber mainly consists of following components : scrubber body or tower (packed column), tower packing (structured or random), droplet separator, spray nozzle(s) or liquid distributor, pump, chemical dosing system and a ventilator. Part from the tower packing, we also supply droplet separators, demisters, spray nozzles, liquid distributors, liquid collectors, liquid redistributors, support plates, hold-down grids, etc.
Packed Column Design
Correct packed column design, correct dimensioning and correct selection of internals, as described above, is a matter of know-how and experience. Part from determining the colum diameter and colum height, it includes the art and knowledge of selecting a type and size of column packing. This is probably one of those areas of engineering where past experience with specific applications is the best guide. Consult us for a quotation, whether it's for a new gas scrubber or stripper-absorber installation or for the optimization of an existing installation in this area.