Abstract:
This paper was to study the improvement of pulverized burner performance by increasing the area of the primary air tube to be up to 2.25 times of previous pulverized burner and study torrefied biomass combustion by using experimental set and mathematic model as a tool for combustion analysis. This combustion was at the rate of 300 kW thermal, 15 percent excess air, the ratio of 25:65:10 for primary, secondary and tertiary air ratio respectively, the fuel size of 0.5 and 1.0 mm which was sieved. The result of simulation showed that using modified pulverized burner in combustion of biomass resulted in flow vector field of combustion which spreaded to pre-chamber wall by high speed of tangent velocity. This leads to turbulence and mixing between air and fuel better. Using pulverized burner has been made reaction rate of combustion better than previous pulverized burner. Experiment result from combustion was found that using the modified pulverized burner made the spread of temperature within pre-chamber better than using the previous pulverized burner. Gas of CO measured from the combustion using previous and modified pulverized burner were 28.5 and 106.6 PPM respectively. Oxide of Nitrogen measured from the combustion using previous and modified pulverized burner were 245.8 and 214.4 PPM respectively. Also, this study showed that torrefied biomass fuel was alternative fuel in the future, it had specific heat by mass higher than other biomasses. Simulation result was shown that position behind the Bluff body reacted at low rate of combustion because torrefied biomass required more amount of air compared to biomass. This lead to let fuel which has little amount of volatile matter release slower than biomass and the rate of combustion increased at position away from Bluff body. The experiment result was found that torrefied biomass combustion occurred along the rotation of secondary air way and the combustion began to occur at position away from Bluff body on the fact that gas of CO and Oxide of Nitrogen measured from the combustion were 64.00 and 196.5 PPM respectively.