Analysis of thermal decomposition and pyrolisis reaction kinetics of Spirulina platensis residue (SPR) was performed using Thermogravimetric Analyzer. Thermal decomposition was conducted with the heating rate of 10, 20, 30, 40 and 50oC/min from 30 to 1000oC. Thermogravimetric (TG), Differential Thermal Gravimetric (DTG), and Differential Thermal Analysis (DTA) curves were then obtained. Each of the curves was divided into 3 stages. In Stage I, water vapor was released in endothermic condition. Pyrolysis occurred in exothermic condition in Stage II, which was divided into two zones according to the weight loss rate, namely zone 1 and zone 2. It was found that gasification occurred in Stage III in endothermic condition. The heat requirement and heat release on thermal decomposition of SPR are described by DTA curve, where 3 peaks were obtained for heating rate 10, 20 and 30°C/min and 2 peaks for 40 and 50°C/min, all peaks present in Zone 2. As for the DTG curve, 2 peaks were obtained in Zone 1 for similar heating rates variation. On the other hand, thermal decomposition of proteins and carbohydrates is indicated by the presence of peaks on the DTG curve, where lignin decomposition do not occur due to the low lipid content of SPR (0.01wt%). The experiment results and calculations using one-step global model successfully showed that the activation energy (Ea) for the heating rate of 10, 20, 30, 40 and 50oC/min for zone 1 were 35.455, 41.102, 45.702, 47.892 and 47.562 KJ/mol, respectively, and for zone 2 were 0.0001428, 0.0001240, 0.0000179, 0.0000100 and 0.0000096 KJ/mol, respectively.Keywords: Spirulina platensis residue (SPR), Pyrolysis, Thermal decomposition, Peak, Activation energy.Article History: Received June 15th 2017; Received in revised form August 12th 2017; Accepted August 20th 2017; Available onlineHow to Cite This Article: Jamilatun, S., Budhijanto, Rochmadi, and Budiman, A. (2017) Thermal Decomposition and Kinetic Studies of Pyrolysis of Spirulina platensis Residue, International Journal of Renewable Energy Development 6(3), 193-201.https://doi.org/10.14710/ijred.6.3.193-201
Spirulina platensis microalgae is one of the feedstocks used in the production of the third generation of biofuel. The extraction of its lipid for biodiesel leaves behind a residue, which can be treated by pyrolysis to create certain other value-added products. This paper discusses the effects of Spirulina platensis residue (SPR) with respect to grain size (0.105, 0.149 and 0.177 mm), temperature (300 to 600°C) and amount of catalyst (0, 10, 20 and 40 wt.%) on the characteristics of products (bio-oil, water phase, char and gas) obtained from pyrolysis in a fixedbed reactor. The results of the study show that the higher the pyrolysis temperature, the higher the conversion. For the bio-oil product, the optimum temperature is 500°C, which produces a peak yield of 35.99 wt.%. The larger the grain size, the lower the bio-oil yield, gas water and gas, for all of the tested temperatures (300-600°C). The amount of catalyst and the pyrolysis temperature greatly influence the quality of bio-oil products, grouping them into the fractions of LPG (C ≤ 4), gasoline (C5-C11), biodiesel (C12-C18) and heavy naphtha (C ≥ 19). The tendency for LPG-Gasoline formation at optimum conditions, considering the use of a 10 wt.% catalyst at a temperature of 400-500°C, was reported.
With a motto of preserving nature, the use of renewable resources for the fulfillment of human needs has been seen echoing these days. In response, microalgae, a water-living microorganism, is perceived as an interesting alternative due to its easy-to-cultivate nature. One of the microalgae, which possess the potential for being the future source of energy, food, and health, is Spirulina plantesis. Aiming to identify valuable chemicals possibly derived from it, catalytic and non-catalytic pyrolysis process of the residue of S. plantesis microalgae has been firstly carried out in a fixed-bed reactor over the various temperature of 300, 400, 500, 550 and 600 °C. The resulting vapor was condensed so that the liquid product consisting of the top product (oil phase) and the bottom product (water phase) can be separated. The composition of each product was then analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). In the oil phase yield, the increase of aliphatic and polyaromatic hydrocarbons (PAHs) and the decrease of the oxygenated have been observed along with the increase of pyrolysis temperature, which might be useful for fuel application. Interestingly, their water phase composition also presents some potential chemicals, able to be used as antioxidants, vitamins and food additives.
The reactions involved in methanol-to-hydrocarbon (MTH) conversion are complex and simultaneous. In this study, the influence of the temperature and weight hourly space velocity (WHSV) was investigated on the MTH kinetic model, which was built on the hydrocarbon pool mechanism using a catalyst of Ca-ZSM-5 (Ca-ZS-5). The existing kinetic model to describe the MTH process is a seven-lump model. The application of any kinetic model for the MTH reaction using the Ca-ZS-5 catalyst has not yet been studied. To obtain high accuracy, new kinetic models were constructed, namely, four- and eight-lump kinetic models. The four-lump model contained oxygenate, olefins, C5+ and paraffin. The eight-lump kinetic model included methanol, dimethyl ether, ethylene, propylene, butylene, C1–C4 (sum of CH4, C2H6, C3H8, i-C4H10, and n-C4H10), C5+ (sum of i-C5H12, n-C5H12, and 1-C5H12), and coke. The MTH experiment was performed at 673–773 K and WHSV values of 4.75, 9.5, and 14.25 h–1. The model simulation was carried out by fitting the model equation and experimental data to obtain kinetic parameters using MATLAB software. The results indicated that the four- and eight-lump kinetic models can accurately explain the behavior of the reaction kinetics, especially on the effect of the temperature and WHSV.
Tung oil with an iodine value (IV) of 99.63 g I2/100 g was epoxidized in-situ with glacial acetic acid and hydrogen peroxide (H2O2), in the presence sulfuric acid as catalyst. The objective of this research was to evaluate the effect of mole ratio of H2O2 to unsaturated fatty acids (UFA), reaction time and catalyst concentration in Tung oil epoxidation. The reaction kinetics were also studied. Epoxidation was carried out for 4 h. The reaction rates and side reactions were evaluated based on the IV and the conversion of the epoxidized Tung oil to oxirane. Catalytic reactions resulted in higher reaction rate than did non-catalytic reactions. Increasing the catalyst concentration resulted in a large decrease in the IV and an increase in the conversion to oxirane at the initial reaction stage. However, higher catalyst concentration in the epoxidation reaction caused to a decrease in reaction selectivity. The mole ratio of H2O2 to UFA had an influence identical to the catalyst concentration. The recommended optimum mole ratio and catalyst concentration in this study were 1.6 and 1.5%, respectively. The highest conversion was 48.94% for a mole ratio of 1.6. The proposed kinetic model provided good results and was suitable for all variations in reaction temperature. The activation energy (Ea) values were around 5.7663 to 76.2442 kcal/mol. Copyright © 2020 BCREC Group. All rights reserved
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