Specific Fuel Oil Consumption

i know it seams to be a silly question

for fuel consumption = 191 g/kWh
is that means 191 gallons per hour?

 

191 grammes per hour per kilowatt generated.
You are using SI units.

The energy contained in the fuel depends of the mass of the fuel, not on the volume, because the volume depends on temperature.

btw, the BSFC is a map depending on the load and rpm. When a single figure is published, it is generally the best point of the map. near full load at the max torque point. Operating at full rpm, full power, or near idle may give very different figures.