# Thermogravimetry Applicability in Compost and Composing Research: A Review
## 3 Results and Discussion
### Thermogravimetry in Compost Pyrolysis
#### 3.4.3 Thermogravimetry in Kinetic of Compost Pyrolysis  
The kinetics of pyrolysis of composts have been studied by thermogravimetric analysis. In this sense, the first papers in the bibliography [96; 97] related to the kinetics of compost pyrolysis, by using thermogravimetric analysis, are related to municipal solid waste composts. The kinetic model proposed by [PERSON] [98] is shown to be adequate to describe the first step of thermal decomposition of those compost components, which is related to the decomposition of cellulosic products. On the other hand, [PERSON] et al. [96] and [PERSON] et al. [97] calculated the kinetic parameters by using the Flynn-Wall--Ozawa isoconversional method at a 95% confidence level. Later, other kinetic models, based on the selective degradation, by thermogravimetric techniques, of the compost components during pyrolysis were also studied [98]. In addition, [PERSON] et al. [93] observed a certain catalytic role of composting by-products in the pyrolysis of food waste composite. In this sense, the thermal behavior of these wastes could be successfully modeled using first and third order chemical reactions within the temperature ranges of 200-360 and 360-510 \({}^{\circ}\)C, respectively, obtaining activation energies varying between 25.68 and 41.89 kJ mol\({}^{-1}\). [PERSON] et al. [99] focused on the pyrolysis and combustion processes for date palm biomass wastes using TGA. This study gave them the opportunity to draw their attention to the kinetic analysis of this biomass and a detailed description of the methodology used is included in the article. Their calculations were based on the Arrhenius equation since, fundamentally, every kinetic model obeys it. The extent of the reaction was measured as a function of the mass loss in the biomass sample or the mass of volatile compounds generated. The activation energy and the pre-exponential factor of the Arrhenius equation for the different peaks found in the thermograms, both in combustion and in pyrolysis, have been obtained. The regression analysis yielded high correlation coefficients (0.81-0.99%) for the studied components. Different activation energies for various date palm biomass, as a result of different chemical reactions under thermal degradation have been found. Therefore, the activation energies under oxidative atmosphere appeared to be higher than under nitrogen atmosphere. From these data, the authors also concluded that thermal degradation of palm biomass, under oxidative atmosphere, had been influenced by heat and mass transfer limits. Due to the high calorific values and high volatile content of date palm seed and leaf, it was concluded that they can become useful sources of energy, chemicals and bio-char. [PERSON] et al. [100] evaluated the influence of municipal solid waste composting conditions on the pyrolysis susceptibility. The activation energy values of these composts are in the range of 57.78-581.69 kJ mol\({}^{-1}\). The assumption that the compost pyrolysis adjusts to a first order kinetics seems to be a suitable approach for municipal solid waste compost. Analysis of the gases produced by the pyrolysis process revealed that hydrogen increases in concentration as the composting time advances to an intermediate time. In this way, the composting process could be a suitable pre-treatment to improve the obtaining of hydrogen through pyrolysis. Moreover, [PERSON] et al. [83; 101] studied the effect of composting on hydrogen production from biomass and compost pyrolysis. Based on the data shown, hydrogen production is positively affected by composting, increasing the hydrogen concentration in the raw gas from 15.2 to 22.6% in volume with respect to non-composed biomass. It is accompanied by a decrease in carbon monoxide concentration. This fact could be explained as a consequence of the physicochemical changes associated with composting, mainly in the thermophilic stage. After this stage, no progress on hydrogen production has been observed.