System and method for controlling the calorie content of a fuel

A system for providing fuel having a desired calorie content to a combustion engine over a range of operating levels, comprising:

• a. a first fuel supply pipe containing a first fuel;
• b. a second fuel supply pipe containing a second fuel and connected to the first fuel supply pipe at a mixing point so that the first fuel mixes with the second fuel to create a mixed fuel having a first calorie content;
• c. a control valve in the second fuel supply pipe upstream of the mixing point;
• d. a process system downstream of the mixing point for processing the mixed fuel to create a processed mixed fuel having a second calorie content;
• e. a trim calorimeter downstream of the process system that produces a trim control signal reflective of the second calorie content of the processed mixed fuel;
• and
• f. a controller connected to the control valve for adjusting the control valve based on the trim control signal from the trim calorimeter.

A method for providing fuel having a desired calorie content to a combustion engine over a range of operating levels, the method comprising:

• a. determining the desired calorie content of the fuel;
• b. mixing a first flow of fuel with a second flow of fuel to produce a mixed fuel having a first calorie content;
• c. measuring the first calorie content of the mixed fuel;
• d. processing the mixed fuel to produce a processed mixed fuel having a second calorie content;
• e. measuring the second calorie content of the processed mixed fuel;
• f. adjusting the second flow of fuel based on the desired calorie content, the first calorie content of the mixed fuel, and the second calorie content of the processed mixed fuel.