This paper presents the experimental study of the types of mixers used in mixing natural gas with air to operate the irrigation pump to save energy; many measurements were carried out in the 2021 year in workshops of the Agricultural Engineering Department, Faculty of Agriculture, Ain Shams University, Egypt. Used engine single-cylinder, air-cooled. A new pump with a discharge diameter of 2 inches, which was an Egyptian manufacturer. Before entering the engine, several mixers were manufactured to mix natural gas with air. Three types of mixers were used using iron pipes of different diameters: Mixer with a perforated inner tube of 8, 10. Using the engine speed measuring device, 12cm (L8, L10, L12) was selected to determine the four shaft speeds (1750, 2300, 2900 and 3500 rpm). The results here dealt with the study of the analysis of technical indicators for the types of mixers used in mixing natural gas with air to operate the irrigation pump where the actual power (Braking power) is superior to all types when operating with gasoline (3.07 kW). A comparison with natural gas, where the mixer type (L10) (2.69 kW) was 10% less than gasoline. The lowest Specific fuel consumption (s. fc) for gasoline was (219.025 gm/Kw.h) at an engine speed of (2900 rpm). The lowest (S.fc) for the types of mixers was the mixer (L10) (340.144 gm/Kw.h) at an engine speed of (2900 rpm). The highest pump discharge was with the L8 mixer (32.98 m3/h), an increase of 1.8% over gasoline at an engine speed of (3500 rpm). The highest actual hydraulic power with the L10 type mixer compared to other type L mixers (0.782 kW) was 12 % lower than gasoline. As for the economic indicators, the lowest Internal Rate of Return (IRR) was gasoline ( 0.44), and the highest (IRR) when carrying the mixer type (L8) was (0.60), an increase of 26.6 % over gasoline. The lowest payback period was for the type of mixer (L8) (1.66 years), and the highest payback period was When the Gasoline was (2.27 years). Keywords: Irrigation pump, natural gas, gasoline, mixer, Engine speed, power, economic.
