Packing element, structured packing and use of structured packing

A packing element, comprising a collection-predistribution unit, a fluid uniform distribution unit, and an opening window unit that are sequentially arranged, wherein:

• the fluid uniform distribution unit comprises a first substrate and a plurality of orifices arranged on the first substrate, the orifices are circular and/or semicircular, and each of the orifices has an equivalent diameter of 1-5 mm, wherein the orifices are cross-arranged with 3-10 layers, and a proportion of a total area of the orifices in a total area of the fluid uniform distribution unit is 40-80%;
• and
• the opening window unit comprises a second substrate and a plurality of windows arranged on the second substrate, and each of the windows has a length proportional to 0.5 power of the fluid viscosity;
• wherein a substrate region between any two adjacent windows in the opening window unit is a wall surface, and a width of the wall surface in each substrate region is not greater than ¼ width of each window, and is not less than 3 mm;
• wherein an arrangement of the plurality of windows in the opening window unit comprises in-line, staggered, or cross arrangement;
• wherein the collection-predistribution unit comprises a third substrate and folded sheets located at an edge of the third substrate, the folded sheets are distributed sequentially along the edge of the third substrate, a V-shaped structure is formed between any two adjacent folded sheets, and the V-shaped structure has an included angle of 120-150°;
• and
• wherein a ratio of the height of the collection-predistribution unit to the height of a single packing element is in a range of 1:10-1:25, and a ratio of the height of the fluid uniform distribution unit to the height of a single packing element is in a range of 1:8-1:25.