1,3-Butadiene recovery from crude C4 streams commonly relies on extractive distillation using selective solvents such as NMP, DMF or ACN because the C4 components have difficult relative volatilities. Structured packing can be used in selected extraction, rectification and recovery sections, but the high solvent-to-vapor ratio, solvent distribution, acetylene impurities, polymerization tendency and solvent-recovery system must be considered together. The packing should support the licensed extraction process rather than being selected from nominal surface area alone.

Structured packing can be used in acrylonitrile absorbers where efficient mass transfer and low pressure drop are required, but polymerization and fouling make long-term reliability a central selection criterion. Documented industrial practice uses smooth-surface structured packing to reduce absorber pressure drop and potentially lower gas inlet temperature, helping reduce polymerization risk. Packing geometry, liquid distribution, upstream quench carryover and fouling severity should be evaluated together, and severe fouling may justify more open grid-type internals rather than progressively finer structured packing.

Structured packing can be used in propylene oxide purification where high stage efficiency is required to reduce methanol, water, aldehydes, methyl formate and other trace impurities. Because several contaminants are difficult to remove by ordinary binary distillation, PO purification may combine azeotropic, extractive or chemically assisted separation. Packing selection should therefore follow the specific column section, impurity target, solvent system, vapor and liquid loads, distributor performance and hydraulic capacity rather than relying on product purity or nominal surface area alone.

Structured packing can be used in hydrogen peroxide concentration columns operating under vacuum because it provides effective vapor-liquid contact with relatively low pressure drop and liquid holdup. In this oxidizing service, packing selection must also consider approved material compatibility, strict contamination control, liquid distribution and drainage. Higher packing efficiency alone is not the objective; the complete contacting system should achieve the required separation without adding unnecessary temperature, pressure loss or retained liquid inventory.

Structured packing can be used in hydrochloric acid rectification and recovery columns, but the HCl-water azeotrope limits what ordinary single-pressure distillation can achieve. Higher acid concentrations may require dual-pressure or extractive rectification, while the packing must be selected for the actual pressure, liquid composition, impurities and highly corrosive environment. Packing efficiency cannot overcome the azeotrope; its role is to provide reliable mass transfer and hydraulic performance once the appropriate HCl recovery process has been defined.