Propane and propylene are two common substances in the field of petrochemicals. It is of great significance to effectively separate them. Propane-Propylene (PP) Splitter realizes the separation function based on the difference in physical properties between the two.

Boiling point is an important physical property difference between propane and propylene. The boiling point of propane is about -42.1℃, while the boiling point of propylene is about -47.6℃. The Propane-Propylene (PP) Splitter, which uses the principle of distillation, can take advantage of this boiling point difference by precisely controlling temperature and pressure. In the distillation tower, the mixture is heated, and the propylene with a lower boiling point will be the first to vaporize and rise to the top of the tower, while the propane with a relatively higher boiling point will remain more at the bottom of the tower, thus achieving preliminary separation.

Differences in molecular size and shape also help separation. Although propane molecules (C₃H₈) and propylene molecules (C₃H₆) have similar numbers of carbon atoms and hydrogen atoms, propylene molecules have carbon-carbon double bonds, which makes their molecular shape and electron cloud distribution different from propane. Some separators based on the principle of adsorption take advantage of this difference, and the adsorbent surface has different adsorption capacity for propane and propylene molecules. For example, the pore size and distribution of chemically active sites of a specific molecular sieve adsorbent can make propane and propylene molecules have different adsorption rates and adsorption amounts on the adsorbent surface, thereby separating the two.

The diffusion rate is also different. Due to differences in molecular weight and intermolecular forces, propane and propylene have different diffusion rates under the same conditions. In the membrane separation process, this difference in diffusion rate can be used. When a propane-propylene mixture passes through a special separation membrane, propylene molecules may pass through the membrane faster than propane molecules, resulting in enriched propylene on one side of the membrane and relatively propane-enriched gas on the other side, achieving the purpose of separation. By deeply exploring these separation principles based on differences in physical properties, the design and operation of the Propane-Propylene (PP) Splitter can be continuously optimized to improve separation efficiency.