Non-catalytic and Catalytic Pyrolysis of Spirulina Platensis Residues (SPR) in Fixed-Bed Reactors: Characteristic and Kinetic Study with Primary and Secondary Tar Cracking Models

Abstract

Spirulina platensis residue (SPR) pyrolysis can produce tar fuels. The use of a silica-alumina catalyst will improve fuel quality by reducing oxygenate compounds. The kinetics of non-catalytic reactions and SPR catalytic pyrolysis have studied using the primary and secondary cracking model approaches. Data obtained from a fixed-bed reactor at 300-600 â°C is the weight of tar each time, weight gas, and char gained at the end of the process. A pyrolysis scheme is made to determine the reaction of product formation with primary and secondary cracking models. From the calculation of pyrolysis without catalyst, the activation energy obtained in primary cracking is E₁, E₂, E₃, while for secondary cracking is E₄ and E₅. The optimum condition in primary cracking is E₃. The SPR reaction becomes char (B→C(1)) with the lowest activation energy of 15.418 kJ/mol (k₃ in the range of 0.1044-0.0279 sec^-1), while for secondary cracking, the tar (1) reaction becomes char (T(1)→C(2)) of 15.151 kJ/mol (k₅ in the range 1.80.10^-6-5.48.10^-7sec-¹). In pyrolysis with silica-alumina catalyst (10, 20 and 40 wt.%), The more catalyst used, the smaller the E_a, and optimal for primary cracking in the use of catalyst 40 wt.%, .ie., in the decomposition of SPR to char, E₃ of 3.004 kJ/mol (k₃ in the range 0.0616-0.0528 sec^-1). For secondary cracking in the use of catalysts 10, 20, and 40 %, E₄ and E₅ are relatively high, i.e., in the range of 40.855-52.085 kJ/mol (k₄ and k₅ in the range 3.89.10^-6-8.40.10^-7sec^-1).