Non-isothermal kinetic study of de-oiled seeds cake of African star apple ( Chrosophyllum albidum ) using thermogravimetry

Abstract

Thermal decomposition and kinetics behaviour of the de-oiled seed cake of African star apple (Chrosophyllum albidum) has been investigated using thermogravimetry under the nitrogen atmosphere from ambient temperature to 900 °C. The thermogravimetric data for the cake decomposition at six different heating rates (5, 10, 15, 20, 30 and 40 °C/min) were used to evaluate the kinetic decomposition of the cake using Friedman (FD), Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) models. Thermal decomposition of the cake showed thermograms indicating dehydration and devolitilization stages (200–400 °C). The maximum temperature for the decomposition of the cake (Tmax) increases from 289.42–335.96 °C with increase in heating rates. The average apparent activation energy (Ea) values of 153.15, 145.14 and 147.15 kJ/mol were calculated using Friedman, Kissinger-Akahira-Sunose, and Flynn-Wall-Ozawa models respectively. The extent of mass conversion (α) shows dependence on apparent activation Ea values which is an evidence of multi-step decomposition kinetic. The thermal profile and kinetic data obtained could be helpful in evaluating the thermal stability of the cake as well as modeling, designing and developing a thermo-chemical system for the conversion of the cake to fuel.

Catalytic pyrolysis of coconut oil with Ni/SBA-15 for the production of bio jet fuel

“…One of the methods used to measure the rate of thermal/thermo-catalytic decomposition or the degree of conversion of a given sample is through the loss of mass of that sample, using eqn (1) : where m i is the mass of the sample at the beginning of the reaction, m t is the mass of the sample at a given temperature and m f is the mass of the sample at the end of the reaction, with the extent of conversion symbolized by α . 93 …”

“…where m i is the mass of the sample at the beginning of the reaction, m t is the mass of the sample at a given temperature and m f is the mass of the sample at the end of the reaction, with the extent of conversion symbolized by a. 93 According to Almeida 94 and Ramani and collaborators, 95 the speed of a reaction depends on the extent of conversion (a), temperature (T), and time (t), and this relationship is expressed according to eqn (2):…”

Thermogravimetric analysis of the combustion of marine microalgae Spirulina platensis and its blend with synthetic waste

“…However, fossil-based energy resources are becoming exhausted, and the carbon dioxide which is released during the combustion process has alarming consequences on the environment. To guarantee future survival, developing sufficient supplies of environmentally-friendly and renewable energy is critical [ 2 , 3 , 4 , 5 ]. Among renewable energy sources, biomass has emerged as an excellent contender for energy production due to its abundance and the fact that it can be sourced from all over the world.…”

Ki̇raz Çeki̇rdeği̇ Pi̇roli̇z Ki̇neti̇ği̇ni̇n Model İçermeyen Ve Model Bazli İntegral Ki̇neti̇k Yöntemler Kullanilarak İzotermal Olmayan Termogravi̇metri̇k Anali̇z Veri̇leri̇ Üzeri̇nden İncelenmesi̇

“…Bunlardan birincisi izotermal (ya da statik) TGA, ikincisi ise izotermal olmayan (ya da dinamik) TGA yöntemi olarak adlandırılır. TGA yöntemi biyokütle maddelerin bozunma karakteristiklerinin ve kimyasal kinetiklerinin incelenmesinde kullanılan ısıl tekniklerden birisidir [8]. Piroliz proseslerinde, biyokütlenin dönüşümü ısıtma periyodu esnasında başladığından ve piroliz proseslerinin hemen hemen tamamı izotermal olmayan koşullarda gerçekleştiğinden izotermal olmayan yöntemin kullanılması uygun olmaktadır [9].…”

“…Model içermeyen yöntem belirli bir dönüşüm değerindeki aktivasyon enerjisinin hesaplanmasına olanak tanır. Bu işlem, farklı dönüşüm değerleri için tekrarlanır ve sonuçta aktivasyon enerjisi dönüşümün fonksiyonu olarak elde edilir [8]. Model içermeyen kinetik yöntem kendi içinde türevsel ve integral olmak üzere iki ayrı sınıfa ayrılır.…”