China's oil demand is expected to fall by 600,000 barrels a day, or 8.9%, in 2026, marking a third straight annual decline, while refining capacity is forecast to shrink up to 5.5% from 2026 levels by 2030, according to Sinopec's research arm.Oil demand destruction, or a long-term drop in consumption, at the world's largest oil importer has been a key factor in capping China's crude imports and global oil prices, despite severe disruption in supplies via the Strait of Hormuz due to the Iran war.Gasoline and diesel are expected to lead the consumption decline in China, falling 8.7% and 11.4% to 149mn metric tonnes and 164mn tonnes, respectively, in 2026. Meanwhile, jet fuel demand could rise 1.3% year on year to 41.55mn tonnes in 2026, the Sinopec Economics & Development Research Institute said in a report.China's chemical industry profits surged by over 50% year on year in the first seven months, but apparent demand remains depressed, with full-year ethylene-equivalent consumption forecast to contract 8.0% year on year amid high costs and inventory headwinds, it added.For refining, the institute cut its forecast for China's 2026 crude processing to 697mn tonnes between the second and third quarters.Sinopec, the world's largest refiner, earlier set its oil throughput target at 113mn tonnes for the second half of the year, stable versus the first half, according to the company's interim report.The research unit said China's refining capacity was expected to rise to 952mn tonnes per year (19.04mn bpd) in 2026. However, tighter policy constraints and falling demand would accelerate the elimination of excess capacity, it added.It also estimated that small and medium-sized refineries with simple product slates, representing a combined 80mn to 100mn tonnes per year of refining capacity, would exit the market.This would reduce China's annual refining capacity to 900mn to 910mn tonnes by the end of 2030, the research unit said.