Refinery runs climbed 5% from the year before to 52.1 million tonnes, or 12.68 million barrels per day (bpd), matching record daily levels racked up earlier this year, data from the National Bureau of Statistics showed.
Privately owned Hengli Petrochemical Co Ltd started trial runs around five months ago at its 400,000 bpd plant in northeast China, with production expected to hit full capacity later this month.
"Throughput at Hengli and ... teapot refineries increased significantly," said Wang Zhao, head of crude oil research at Sublime Information Co. Independent refiners in China are often referred to as 'teapots'.
The return of refineries after maintenance contributed to the higher runs in April, Wang added.
The robust crude runs, which stood in contrast to slower-than-expected growth in China's industrial output last month, also come amid mounting efforts by state majors to export refined products to offset domestic gluts.
PetroChina shipped gasoline from domestic refiners to Nigeria for the first time in the first quarter.
For the first four months of 2019, crude runs were up 4.7% from a year earlier at 207.47 million tonnes, or 12.62 million bpd, the data showed.
Crude oil output stood at 15.71 million tonnes, or 3.82 million bpd, down from 3.89 million bpd in March.
Natural gas output came in at 14.1 billion cubic metres (bcm) in April, up 7.9% from the same month a year earlier, but the lowest level since October 2018 due to slower demand towards summer.
(Reporting by Meng Meng and Aizhu Chen; Editing by Joseph Radford)