Based on the source of raw materials, the production of polyvinyl alcohol (PVA) can be categorized into four methods: the calcium carbide-acetylene method, the natural gas-acetylene method, the petroleum-ethylene method, and the biomass-ethylene method; however, the subsequent processing steps-including polymerization, recovery, alcoholysis, and packaging-are similar across all four routes. The biomass route, specifically, utilizes raw materials such as sugarcane to produce PVA. A project with an annual capacity of 60,000 tons for the production of specialty PVA resins via the ethylene method commenced operations in 2024.
In this process, vinyl acetate (VAC)-derived from either acetylene or ethylene-serves as the polymerization monomer; methanol acts as both the solvent and chain transfer agent; and azo or peroxide compounds function as initiators for a partial solution polymerization reaction. Subsequently, unreacted monomers are removed to yield a methanol solution of polyvinyl acetate, which is then fed into the alcoholysis stage. Here, a transesterification reaction takes place under alkaline catalysis. Following crushing, pressing, and drying, the final PVA product is obtained and pneumatically conveyed to the packaging station.
Since the commissioning of the 60,000-ton-per-year specialty PVA resin project utilizing the ethylene method, both energy consumption and carbon emissions have been reduced. Additionally, a separate project with an annual capacity of 200,000 tons for the production of functional PVA resins via the ethylene method has entered the engineering design phase.
