# Thermogravimetry Applicability in Compost and Composing Research: A Review
## 3 Results and Discussion
### Thermogravimetry in Kinetic of Compost Combustion  
[PERSON] et al. [74] investigated the potential vaporization of compost from animal breeding by combustion and pyrolysis using thermogravimetric analysis (TGA) coupled with mass spectrometry (MS) detector in order to define its potential energy production. The kinetic parameters of the pyrolysis and combustion procedures were attained by TGA. They found a significant water rate in the samples studied, a fact that constitutes a serious drawback since it can cause feeding and fluidization problems. For this reason, it is recommended to conduct a pre-drying process of the material before its use as energy compost, a technique that usually involves high operating costs. Thermogravimetric analyses (TGA) is a suitable method to determine the kinetic parameters of thermal degradation processes in composts [74; 75; 76; 77; 78]. In this sense, the assessment of kinetic parameters can be carried out from TGA data to which techniques known as model-fitting and model-free are applied, including the identification of the kinetic reaction model or lack thereof. In general, the kinetic model used was derived from the Arrhenius equation and first order reaction has been assumed [76], although some authors have described it as a function of other reaction orders that implies the existence of parallel reactions between the main components of biomass (hemicellulose, cellulose, and lignin) [77]. Based on TGA data, the activation energy (Ea) values involved in the composting processes could be calculated to find the maximum energy efficiency, i.e., the most profitable operating conditions for the production of an incinemable product. To determine that activation energy for the obtained composts, model-free methods (for example, the isoconversional method) are believed to be one-step kinetics and this is the reason why their use is suggested in determining combustion kinetic data. Of these isoconversional practices, the Flynn-Wall-Ozawa integral method may be one of the most widely employed [78; 79]. In this line, [PERSON] et al. [77] investigated the valorization under combustion of MSW compost by TGA. They measured the maturation of MSW compost and studied the influence of the selected composting parameters, such as aeration and moisture content, on the actual heat capacity of the material. Based on the thermal degradation (TGA) and differential mass loss (DTG) thermograms they observed that both composting operating parameters affected the biodegradability of compost (Kb = 0.36 and 0.42) and more importantly, their gross heating values. An evident growth in heating values was observed for both reactors after 40 days (when the maturation stage had finished). The increments were linked to fulvic and humic acids formation since, according to [PERSON] et al. [80], the calorific values of these acids are analogous to those found for lignite (coal). It was concluded that composting MSW under appropriate conditions was not only an ideal process, able to concentrate and stabilize the calorific power of the material, but also a convenient body drying process. [PERSON] et al. [81] demonstrated that the utilization of MSW based compost for energy generation is possible when some technological modifications of the materials are made. The aim of these adjustments is to produce final fuels with gross calorific figures above 10 MJ kg-1 based on dry matter. When aiming to use the compost as low-energy fuel, the main problem they found, which is the foremost drawback experienced by other authors, was its excessive moisture content. The authors observed that, to generate a net calorific value (NCV) greater than 10,000 kJ kg-1 a reduction of the water content of the compost to values close to 12% was necessary. This reduction in moisture could take place spontaneously by means of extending up to six months the maturation periods or by wastewater addition.