126 The Philippine Journal of Science i9i8 



tough layer of clinker that continuously deposited on the surface 

 of the grate. The removal of this deposit was extremely diffi- 

 cult. The heat evolved by the coal was so intense that it caused 

 the grate bars to burn out. To counteract the excessive heat 

 of the fire bed and the formation of clinkers, water was intro- 

 duced into the ash pit. This had to be stopped at once, as it 

 produced pounding of the engine caused by premature ignition, 

 on account of the sudden formation of a large percentage of 

 hydrogen in the gas fuel. 



The logical means to overcome the excessive heat and the con- 

 sequent formation of a large amount of clinker and destruction 

 of the grate bars was to use in the fire bed another endothermic 

 agent that would not liberate hydrogen. This could have been 

 obtained by diverting part of the exhaust gases of the engine 

 into the fire bed of the producer. However, the engine exhaust 

 is situated at a considerable distance from the producer, and 

 there was not at hand the necessary piping, so that the introduc- 

 tion of water in the ash pit was tried again and this time was 

 very successful. It was known from the start that Batan coal 

 contains a very high percentage of moisture, which liberates a 

 corresponding high percentage of hydrogen in the gas. The 

 problem was then reduced to establishing the safe limit of water 

 evaporated in the ash pit. For this purpose the small water- 

 supply pipe leading to the ash pit was provided with two valves 

 in series, the lower one was regulated to suit the necessary 

 evaporation and the upper one was left wide open; the lower 

 valve once regulated was left in its position, and the upper one 

 was used only as a service valve for starting or stopping the 

 water supply. Through these valves a very small amount of 

 water was introduced into the ash pit at first. Very slowly this 

 was increased, and at the same time the effect produced in the 

 engine by the gas explosion was carefully noted. It was found 

 by experiment that the evaporation of 6 liters of water per hour 

 was sufficient to protect the grate and the wall of the producer 

 without causing pounding of the engine, even when under full 

 load. 



The Fushon coal does not form bad clinkers as long as a small 

 amount of steam is blown into the fire bed with air. The steam 

 is obtained from the boiler that supplies steam to the laborato- 

 ries. In independent installations the necessary steam can be 

 obtained from a small boiler heated by the gas-engine exhaust. 

 Usually steam is not necessary when the ash pit is kept flooded 



