The PE-lined ISO tank is the China-Australia chemical-lane workhorse for corrosive cargoes that attack stainless steel. Carbon-steel Q345R shell with a 16 to 20 mm rotomoulded LDPE, LLDPE, or HDPE liner fabricated as a single rotomoulded part inside the steel shell. The lining lets the tank carry hydrochloric acid 35%, sodium hydroxide 30 to 50%, sodium hypochlorite 10 to 15%, phosphoric acid 85%, dilute hydrofluoric acid, dilute sulphuric acid, and a long list of chloride-containing solutions that bare 316L cannot tolerate. Hubei Dongrunze, Henan Lishixin, and Tianjin Longteng build the bulk of the China-export lined-tank fleet.
What PE-lined is built for
The IMDG plate is typically T7 or T11 (sometimes T14 with the lining adding the corrosion margin), but the cargo profile is what matters. Hydrochloric acid 35% (UN 1789, Class 8 PG II) ships in PE-lined T7s by the thousands of tonnes per month from Chinese coastal chemical parks to Vietnam, Indonesia, Australia, and African destinations. Sodium hydroxide 50% (UN 1824) and sodium hypochlorite 10 to 15% (UN 1791) are the other two high-volume cargoes. Phosphoric acid 85% (UN 1805), potassium hydroxide solution (UN 1814), hydrogen peroxide 30% (UN 2014, in compatible PE builds), and sodium hydrogen sulphite solution (UN 2693) round out the standard lined-tank cargo list.
Construction and materials
Carbon-steel Q345R or Q235B shell, typically 6 mm thickness, with a 16 to 20 mm rotomoulded LDPE / LLDPE / HDPE liner. The liner is moulded as a single piece inside the steel shell using rotational moulding equipment that heats and rotates the polymer to form a uniform internal coating. Welded fittings at the manlid and outlet bond to the liner via PE flanges with PTFE-gasketed compression seals. Liner thickness varies by chemistry: 16 mm for sodium hypochlorite where chemistry is mild, 20 mm for concentrated hydrochloric where mechanical-stress resistance matters more.
Liner life on caustic service runs about 5 to 8 years; on concentrated hydrochloric service 7 to 10 years; on phosphoric acid 8 to 12 years. Liners do not survive aggressive mechanical cleaning (high-pressure water jets at over 300 bar pinhole the surface). Operator practice is to use chemical cleaning between cargoes (acid wash for caustic prior, alkaline wash for acid prior) rather than mechanical scrubbing. The China-Australia operator supply chain treats lining replacement as a 5 to 8-year scheduled cost rather than a one-time event.
When PE-lined is the right choice
PE-lined is the right tank for the China-export corrosive-cargo lane. Concentrated hydrochloric acid, dilute caustic, and sodium hypochlorite cannot economically ship in stainless tanks (rapid corrosion creates iron contamination and tank failure). PTFE-lined tanks (the next step up) cost 30% more and have lead times that double. The PE-lined build hits the cost / performance / lead-time intersection for the high-volume mid-corrosive cargo lane.
When PE-lined is the wrong choice
PE-lined is the wrong tank for cargoes that attack LDPE: concentrated sulphuric acid above 75% rapidly destroys the liner, ozone generates pinholes, hot caustic above 60 deg C accelerates degradation, organic solvents swell or dissolve PE depending on the solvent. The decision tree: 35% HCl in PE is fine; 70% HCl needs PTFE; concentrated 98% sulphuric needs PTFE or lead in a T14 build; HF up to 48% can ride PE but 70% HF needs PTFE.
How a PE-lined booking is verified
Pre-loading inspection covers the standard plate stack (CSC, 5-year, 2.5-year, EFTCO ECD) plus a lining-condition check through the manlid. Visual inspection looks for blistering, delamination from the steel substrate, or pinholes (a spark test is sometimes performed after particularly aggressive cleaning). Liner-manufacturer certificate from Marflex, AGRU, or the Chinese rotomoulding houses lists installation date, polymer grade (LDPE / LLDPE / HDPE), liner thickness, and re-test history. A 5 to 7-year-old lined tank with a serviced liner and clean inspection record is normal; a 12-year-old liner with unknown service history is a flag.