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Estimation of Gas Engine Fuel Rates


In this post I want to share how to estimate gas engine fuel rate. We will use heat rates to estimate gas engine fuel rate.

We use graph below for initial estimation of heat rates. Gas engine heat rates is a function of engine ratings.

Graph below is taken from Rule of Thumb for Chemical Engineers by Carl Branan.

Gas Engine Fuel Rates
Gas Engine Fuel Rates

Based on graph above, approximate fuel rates are around 7000-8900 Btu/Bhp-hour. The higher the engine rating, the lower fuel rates will be.

If we assume that gross heating value of fuel gas is around 950 Btu/scf, then fuel gas rate will be 0.000236-0.000300 MMscfd/bkW or 0.000177-0.000225 MMscfd/bhp.

How if the gross heating value is higher?

Let’s say the gross heating value is 1100 Btu/scf. Then fuel gas rate will be lower, which are 0.000204-0.000259 MMscfd/bkW or 0.000153-0.000194 MMscfd/bhp.

I hope you this short post useful 😊