Thermogravimetric analysis kinetic study of Spirulina platensis residue pyrolysis

A Aktawan,S Jamilatun,A Budiman,I Mufandi

doi:10.1088/1755-1315/963/1/012010

Abstract

Bio-oil from microalgae pyrolysis has excellent potential to be developed as a renewable, sustainable, and environmentally friendly energy fuel. Using pyrolysis technology to use the solid waste from microalgae extraction of spirulina platensis as an energy source is a solution for pollution due to biomass extraction. The solid residue is known as Spirulina Platensis Residue (SPR). SPR pyrolysis will produce liquid fuel (bio-oil), gas, and biochar. This paper discusses the study of the pyrolysis kinetics of SPR with Thermogravimetric analysis (TGA) by flowing nitrogen, the settlement method using Kissinger - Akahira - Sunose (KAS) and Flynn -Wall - Ozawa (FWO). The samples were heated at a temperature ranging from 30°C to 1000°C with three different heating levels, namely 10, 30, and 50°C/min yang injected 20 mL/min Nitrogen (N2). The results obtained from the thermal decomposition process show three main stages, namely dehydration, active and passive pyrolysis. The activation energy (Ea) and the pre-exponential factor (A) obtained by the KAS method were around 42.241 kJ/mol, 51.290 kJ/mol, 54.556 kJ/mol, and 61.604 kJ/mol with conversion of 0.2%, 0.3%, 0.4%, while the estimation of activation energy from FWO 48.963 kJ/mol, 58.107 kJ/mol, 61.498 kJ/mol, and 68.457 kJ/mol with conversion of 0.2%, 0.3%, 0.4%, and 0.5% respectively. the kinetic parameter can be described by using this method. The experimental results show that the kinetic parameters obtained from the two methods are slightly different. However, the KAS and FWO methods are quite efficient in explaining the mechanism of the degradation reaction.

Highlights

Renewable energy has been one of the interactive issues in Indonesia for discussion in-depth and development because Indonesia has a substantial potential renewable energy source, sustainable energy, and low carbon emission [1]
Thermogravimetric Analysis The thermal decomposition of Spirulina platensis residue (SPR) can be determined by thermogravimetric analysis shown by the differential thermal analysis (DTA), thermal gravimetric (TG), and differential thermal gravimetric (DTG) curves
The results of the activation energy value calculation, preexponential, can be seen in table 3, which all curves at different heating rates, and we find the appropriate temperature

Summary

Introduction

Renewable energy has been one of the interactive issues in Indonesia for discussion in-depth and development because Indonesia has a substantial potential renewable energy source, sustainable energy, and low carbon emission [1]. One type of biomass as an energy source is microalgae which attract attention and have several advantages, including high yield per area, 15 times higher than palm oil, increased efficiency in absorbing, no competition with agriculture and food. Microalgae cultivation can use photo-bioreactor and open water (sea and pond)[2]. There are three main microalgae components: proteins, carbohydrates, and natural oil (lipids). Microalgae can be converted using pyrolysis to produce bio-fuel about 40% at a temperature ranging from 300°C - 500°C [3]. Pyrolysis is a thermochemical process in which biomass decomposes without

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