A Great Achievement of Calculated and Experimental Results of Char Kinetic Rate in Woody Mahogany Pyrolysis

Department of Mechanical Engineering, Brawijaya University, 65145, Indonesia

^* Corresponding author: widya_dinata@ub.ac.id

Abstract

In the pyrolysis process, it is needed to know the value of k (rate costant) to know the rate of reaction that occurs. It is needed to calculate k caused by T effect due to the reason that it is extremely difficult experimentally to find rate constants. The pyrolysis process was carried out for three hours with the minimum condition of Oxygen using mahogany wood. It was used the pyrolysis temperature variations of 250°C to 800°C. The results showed the increasing temperature and decreasing mass of char as long as the process to obtain, the kinetic rate of char k. We used two calculation approaches method to find the calc ulated k. Fristly, it used the total kinetic rate model equation with the equation k_T = 60.3 e^-2028.4/T and the second one, it was used the local kinetic rate model. In the local kinetic rate approached, it was divided the 3 temperature ranges; k₁ in the range of 28°C - 250°C was k₁ = 539.1 e^-2907.3/T, k₂ in the range of 250°C to 500°C was k₂ = 27.11 e^-1424/T; and k₃ in the range of at range 500°C to 800°C was k₃ = 572.4 e^-4549.2/T. Then, by using the found k values, it was found the great achievement results that the decreasing mass of char in the calculation was coincide with the experimental results. It was used both kinetic rate methods depending on the required energy was needed in the pyrolysis process; at low pyrolysis temperatures, the appropriate kinetic rate model was a local kinetic rate model, and for pyrolysis at high temperatures of 600°C to 800°C, the accurate kinetic rate model was the total kinetic rate model.