High capacity is available for bleach plant chlorine dioxide scrubbers with Lantec fouling resistant Q-PACÒ packing

At the heart of a scrubber system is the mass-transfer, or "packing" media used. Using the appropriate type of packing can turn a costly, non-performing system into a higher performing, less-costly, easier to maintain system. Q-PACÒ packing for new or existing chlorine dioxide scrubbers increases capacity, resistsfouling, decreases column size, and reduces pressure drop for capital and operating cost savings. High efficiency is maintained at high gas velocities of 650 ft/min or even higher. Q-PACÒ has a geometric surface area of over 30 ft²/ft³ and its fine round needles create over 11,000 micro droplets per cubic of packing. This advanced drip-point technology results in extended gas-liquid contact, over twice the amount of the actual plastic surface.

Maximum capacity, unequaled by any other random packing, is provided by Q-PACÒ . A very high void fraction, 96.3%, is obtained from the widely spaced grid and needle design. A typical bleach plant scrubber for ClO₂ and Cl₂ can be designed for 650 ft/min, or higher, gas velocity. New scrubbers can be built with smaller diameters, which reduces capital and fabrication costs, with a smaller system footprint.

The lower pressure drop allows for smaller blower motors, less noise, and lower electrical energy costs. At 650 ft/min and with 4 gpm/ft² of white liquor flow rate, the pressure drop is less than 0.2 inches WC/ft of packing. ClO₂ inlet concentrations vary, as well as specified removal efficiency, which may be from 90 to 99.9 %. Lantec provides free evaluations, process designs and packing recommendations. With a nominal size of 7 inches and a packing factor of just 4 ft(-1), Q-PACÒ provides a combination of gas-liquid contacting efficiency and low pressure drop which is unmatched by any other random dumped packing in the world.

Q-PACÒ is extremely resistant to fouling and plugging because of its unique patented structure. Q-PACÒ has very few flat surfaces for dirt and deposits to accumulate, which makes it almost impossible to plug with scale formation or biological fouling. The openings in Q-PACÒ approach 5/8" and the needle are spaced at least 1/2" apart. This makes it virtually impossible for scale to bridge these gaps when the supporting surfaces are thin and are not flat. The scale will simply fall from its own weight and lack of support. This fouling resistance feature can reduce cleaning and maintenance. In over four years and over 300 applications Q-PACÒ has proven difficult to plug with scale or particulates in the liquid or air. More recently, Q-PACÒ has been in service in the difficult conditions of white liquor scrubbers, where calcium carbonate scaling and fiber fouling have been problems for other packings in the past.

Cost for Q-PACÒ is very economical and competitive. The high void fraction of Q-PACÒ minimizes the material cost of making the packing out of polyvinylidene fluoride(PVDF), which resists damage in the hot, oxidizing conditions of bleach plant scrubbers. The packing is easily handled and installed; the standard 7" size allows the packing to be supported on the open grid supports ordinarily used for structured packing. Structured packing are not easily cleaned, and foul and plug in ClO₂ scrubbers. Lantec has introduced other high performance random packings in the last twelve years, such as LANPACÔ packing, which has also been very successfully used to provide advantages in chlorine dioxide absorbers. The newest Lantec packing is the just introduced 4" size Q-PACÒ , for use in smaller diameter towers.