What is the current price trend for propylene glycol versus glycerin, and what factors are driving the divergence?

What is the current price trend for propylene glycol versus glycerin, and what factors are driving the divergence?
China's PG production relies on two main routes. The PO transesterification method—reacting propylene oxide with methanol to make dimethyl carbonate (DMC)—accounts for about 85% of domestic capacity, yielding PG as a byproduct. Its economics are constrained by PG offtake: with 2021 domestic PG output at 330,000 tons and apparent consumption of 260,000 tons, capacity utilization was only 71%, and producers had no expansion plans, capping new PO-based DMC projects. The alternative EO transesterification route uses ethylene oxide instead, producing ethylene glycol as the byproduct—a far larger market (over 20 million tons apparent consumption in 2021), easing disposal concerns. However, EO-based units have suffered from persistent ethylene glycol oversupply and losses since 2020. Methanol oxidative carbonylation, a third route with minimal byproducts and lower capex (1,000-1,500 yuan/ton), has become the preferred entry method for new DMC players like Shida Shenghua and Hualu Hengsheng.