Sunoco Inc., the largest oil refiner in the Northeast, reported a 7.6 percent gain in its first-quarter profit from operations yesterday, although construction projects at its South Philadelphia refinery slowed production at a time in the quarter when refining profits were highest.

The Philadelphia company said it earned $85 million, or 70 cents a share, compared with $79 million, or 59 cents a share, in last year's first quarter.

Including a $90 million after-tax gain related to last year's sale of units in Sunoco Logistics Partners L.P., Sunoco's net income in the quarter ended March 31 was $175 million, or $1.44 a share.

Revenue from the sale of gasoline, chemicals and other products climbed 8 percent, to $9.31 billion from $8.59 billion in the same quarter a year earlier.

Sunoco's refineries in Philadelphia, Marcus Hook and Westville ran at 82 percent of capacity in the first quarter, down from 93 percent in the same period last year, with most of the shortfall occurring in Philadelphia. That translated into a 9.2 percent decline in the amount of crude oil and other feedstocks processed at the plants.

The forest of construction cranes visible at the Philadelphia refinery from Interstate 95 and other roads have been aiding a $520 million project to expand and upgrade a key processing unit - known as a fluid catalytic cracker - to allow Sunoco to turn more low-value fuel into gasoline and other fuels that fetch more on the markets.

The company said the completion of work in Philadelphia slowed April production. But John G. Drosdick, Sunoco's chairman and chief executive officer, said yesterday in a news release that "our Northeast refining system is now returning to normal operations as we enter the summer driving season."

Sunoco and other refiners make a huge chunk of their profits in the second and third quarters, when families take to the road for vacations.

Beyond refining, Sunoco's results were mostly down. For example, retail operations earned $7 million, compared with break-even results a year earlier, and profit from chemicals that go mainly into plastics fell to $9 million from $14 million a year earlier.

The company's shares closed yesterday at $77.70 on the New York Stock Exchange, up $1.94, or 2.6 percent.

Contact staff writer Harold Brubaker at 215-854-4651 or hbrubaker@phillynews.com.