The PVDF-lined ISO tank uses polyvinylidene fluoride (Solvay’s Solef and Arkema’s Kynar are the two major brands) as the cargo-contact liner. PVDF has chemical resistance close to PTFE but better mechanical properties, including higher tensile strength and better resistance to abrasion. Sodium hydroxide compatibility extends to 140 deg C continuous, which is the highest of any common lining. PVDF is the right choice for many acid and base chemistries where PE is insufficient, PTFE is over-spec, and the temperature envelope demands higher than ECTFE can deliver in some specific applications.
What PVDF-lined is built for
Hydrogen peroxide service in PVDF-compatible builds (PVDF tolerates H2O2 better than many alternatives, with longer liner life on dedicated service). Selected sulphuric and hydrochloric concentrations where the chemistry profile justifies PVDF over PE or PTFE. Sodium hydroxide at elevated temperatures (140 deg C continuous, where PE fails by 60 deg C and PTFE handles 120 deg C). High-purity chemistry for medical and pharmaceutical applications where the liner’s particle-generation profile is critical.
Construction and materials
Carbon-steel or 316L stainless shell, 6 mm reference, with a 3 to 6 mm PVDF sheet liner. The thicker liner range (vs PTFE’s 2 to 5 mm) reflects PVDF’s better mechanical properties and the typical service in higher-temperature applications. Solvay’s Solef PVDF is the premium brand; Arkema’s Kynar is roughly equivalent and competes on price.
When PVDF-lined is the right choice
PVDF-lined is the right tank for the H2O2 lane where the dedicated H2O2 build (T14 in 304L or 316L stainless without insulation, with 10-inch rupture disc) is unsuitable for the specific cargo concentration or buyer specification. PVDF is also the right choice for hot-caustic service (NaOH 50% at 100 to 140 deg C) where PE has failed in service and PTFE costs more than necessary.
When PVDF-lined is the wrong choice
PVDF-lined is the wrong tank for HF service (PTFE is the standard), for ozone or strong oxidiser service at elevated temperature (ECTFE handles this better), and for cargoes where PE-lined service is sufficient (the price premium is wasted).
How a PVDF-lined booking is verified
Pre-loading inspection covers the standard lined-tank plate and lining checks plus the Solvay or Arkema liner certificate listing PVDF grade, sheet thickness, installation date, and last service record. Operator history is the differentiator: a PVDF-lined tank that has run dedicated H2O2 or hot-caustic service for 5+ years has a track record; a recently-converted tank from another service may have residual chemistry concerns.