Aug 1 (Reuters) - Refiner HF Sinclair reported

a lower second-quarter profit on Thursday as margins slumped due

to a tepid summer driving season and a rise in global refining

capacity.

The Dallas-based company posted a net income of $151.8

million, or 79 cents per share, in the quarter ending June,

compared with $507.7 million, or $2.62 per share, a year

earlier.

U.S. refiners ramped up processing capacity to 93.5% in the

second quarter, compared with 91% in the same period last year,

according to the U.S. Energy Information Administration, on

expectations of an uptick in demand that did not materialize.

Fuel demand also came under pressure during the quarter due

to lower manufacturing activity and increasing renewable fuel

supply.

HF Sinclair's ( DINO ) refinery gross margin was $11.33 per barrel in

the second quarter, compared with $21.99 a year earlier.

Its refinery utilization averaged 93.6% in the quarter,

compared with 81.7%.