The calculation of the gaps between molecular sieves in a pressure swing adsorption tower

The calculation method is known. Here is the explanation: Method 1: The so-called dead space refers to those areas where gas is present but has not been adsorbed by the adsorbent. It is essentially the total volume of the tower minus the volume of the adsorbent skeleton (note: it is the volume of the adsorbent skeleton, Vg, and not the volume of the pores in the adsorbent). The gas present in this area is unadsorbed gas. By combining the volume of the dead space with the desorption factor, it is possible to estimate the volume of gas that is released during each pressure equalization process, as well as the volume of gas that is released during reverse operation or venting. For example, if the total volume of the adsorption tower is V, the actual specific gravity of the adsorbent is Dg, and the amount of adsorbent filled in is G (in terms of weight), then the dead volume equals V – G/Dg. The amount of adsorbent G is a value that depends on the total volume; generally, in design, the volume occupied by the adsorbent is set at 0.9 to 0.95 times the total volume of the adsorption tower. If the packing density of the adsorbent is Db, and 0.95 is used as the value here, then G = V × 0.95 × Db, and the dead space becomes V × (1 – 0.95 × Db/Dg). For silica gel, the packing density is usually around 0.76, while the density of the skeleton is around 2.1; thus, the dead space equals V × (1 – 0.95 × 0.76/2.1) = V × 0.656. In fact, if this formula is rearranged, we get dead space/V = 0.656, and this 0.656 represents what is commonly referred to as the porosity rate, although this porosity rate differs slightly from the one associated with adsorbents. Method 2: Porosity w = bulk density of the molecular sieve / (weight of a single molecular sieve particle / volume of a single molecular sieve particle). The volume of a single molecular sieve particle = volume of its solid framework – pore volume

0.9 to 0.95, is that possible?