A PVC lined FRP scrubber for the chlor-alkali industry recently completed its main manufacturing process at our factory (Hebei Jiarui FRP Co., Ltd.) and is currently undergoing on-site assembly of the skid supports. The equipment is scheduled to be shipped by sea to a large chlor-alkali production base in Indonesia in mid-next month to treat acidic components and chlorine entrainment in process tail gas.
Equipment Manufacturing Entering Final Stage
According to the factory, the main body of this scrubber is a composite system with fiberglass (FRP) as the structural layer and polyvinyl chloride (PVC) as the inner lining. Current work focuses on the skid support assembly: the skid supports are the connecting components between the bottom of the equipment and the foundation platform, and their welding alignment accuracy directly affects the verticality and anti-tipping ability of the tower body during transportation and operation. The assembly team is adjusting the anchor bolt positions one by one and applying secondary anti-corrosion treatment to the mating surfaces of the base and the lower end cap of the tower. Considering the high humidity and high salt spray environment at the Indonesian project site, this redundant design is particularly necessary.
Corrosion Resistance Design for the Chlor-Alkali Process
The exhaust gas from the chlor-alkali industry is notoriously corrosive in the chemical industry. Chlorine, hydrogen chloride, and entrained hypochlorous acid droplets released during the electrolysis of brine, if directly discharged into subsequent pipelines, can corrode ordinary carbon steel equipment within months. This PVC-lined FRP scrubber addresses this challenge with a two-layer material design: the inner PVC lining directly contacts the gaseous medium, utilizing its excellent resistance to chloride ion penetration to block chemical attack; the outer FRP layer provides structural strength and resistance to external pressure, while also acting as a backing to prevent excessive deformation of the PVC due to temperature fluctuations. It is worth noting that the two materials are designed with matched coefficients of thermal expansion-a weak point in many past failures.
A Brief Analysis of Scrubber Selection for Chlor-Alkali Operations
It is necessary to point out that not all PVC-lined FRP scrubbers are suitable for handling high-temperature chlorine gas. When the inlet gas temperature exceeds 65°C, the risk of softening of the PVC lining increases dramatically. The equipment exported in this case is suitable because the process parameters provided by the Indonesian project party strictly control the tail gas inlet temperature below 52°C (a quench tower has been installed at the front end). If the temperature is higher, a PP (polypropylene) lining or an all-FRP structure must be used-but the latter two are less resistant to chlorine oxidation than PVC. This trade-off in material selection precisely reflects the practical logic in the chemical corrosion protection field: "There is no best, only the most compromised."
The assembly of the equipment is expected to be completed by the end of this month, followed by a final airtightness test (test pressure 0.12MPa, pressure held for 30 minutes). A nameplate printed with "PVC-lined FRP scrubber"-made of 316L stainless steel, resistant to seawater corrosion-has been customized and awaits installation below the support ring in the middle of the tower body.