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.

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 😊