China's crude oil imports in September perked up from a 22-month low in August, rising 9.1 percent month-on-month to 20.08 million tons, according to General Administration of Customs (GAC) data.

Imports rose in September as purchases of crude oil made in August when international prices were low were delivered, oil industry analyst Dong Lizhu told Interfax.

Increased agricultural activity during the autumn harvest also pushed up fuel demand, added Dong. The average operating rate at state-owned refineries rose 1.6 percentage points from August to 82.4 percent last month.

China imported 3.42 million tons of fuel in September and exported 2.06 million tons.

The average import price of crude oil last month was $108.61 per barrel, up 8.9 percent month-on-month. China raised retail fuel prices for the fourth time in September on higher crude costs.

Global oil prices are expected to increase in the fourth quarter, putting pressure on domestic refiners' margins, according to Dong.

China's dependence on crude imports this year will rise to 58 percent from 56 percent in 2011, the China Petroleum Enterprise Association, a semi-independent industry body, said in March.

On an annual basis crude oil imports declined 1.81 percent in September as a result of weak industrial activity. Data from the National Bureau of Statistics due on Thursday will likely show industrial output grew 9.1 percent in September from a year earlier, according to Moody's.

A breakdown of imports by country for September will not be released until the end of the month. Saudi Arabia and Angola were the biggest exporters of crude to China in August, followed by Russia and Iran.