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| Author(s): |
Sâmilla Gabriella Coêlho Almeida
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Araraquara. 2020-09-24. |
| Institution: | Universidade Estadual Paulista (Unesp). Instituto de Química. Araraquara |
| Defense date: | 2020-07-24 |
| Advisor: | Kelly Johana Dussán Medina |
| Abstract | |
The search for increased use of renewable biomass resources has increased as a way of reducing the impacts caused on the environment by the uncontrolled use of fuels and chemicals derived from petroleum. The use of lignocellulosic biomass has gained importance mainly in the energy sector. The use of sugarcane residues to produce steam, energy and obtain sugars of 5 and 6 carbons is part of the biorefinery concept, which aims at the total, sustainable and competitive use of biomass in a range of marketable products. In this aspect, the objective of this work was the valorization of sugarcane residues through thermochemical processes for the production of value-added bioproducts. The conversion processes investigated were direct combustion and pyrolysis. In the first part of the project, burning tests were carried out on a pilot combustion chamber and the emissions of particles generated from the combustion of the straw/bagasse mixture were quantified. The burning of biomass occurred in 4 ranges of air speeds observed in the chimney (4.19; 5.40; 6.85 and 8.21 m/s). The diluting effect was observed inside the duct when the fluid is at a higher speed, such behavior occurred throughout the particle collection diameter range; with a higher concentration of particulate matter (PM10) in the lowest speed range (4.19 m/s) and lower concentrations for the highest speed (8.21 m/s). The emission factors (EF) obtained in the tests are characteristic for the experimental combustion chamber used and the operational conditions, being in the range of 0.305 - 0.551 g of PM2.5/kg of biomass for the speeds of 4.19 m/s. In the second part of the project, slow pyrolysis reactions were performed in a laboratory-scale fixed bed reactor and the operating conditions were varied: peak temperature and heating rate, in the values of 450, 500 and 600 ºC and 10 and 20 ºC/min; respectively. It was possible to determine the yield of carbonized, bio-oil and non-condensable gases resulting from the process. The carbonized obtained was characterized in terms of immediate and elementary analysis. Yields on a dry basis ranged for carbonized from 21.75 to 36.80 % m/m, for bio-oil between 43.02 to m/m and for non-condensable gases between 20.17 to 28 , 46 % m/m. It was observed that for the same heating rate (10 ºC/min), the carbonized yield decreases and that of bio-oil increases with the increase in the peak temperature. The highest carbonized yield for bagasse was at a peak temperature of 450 ºC and a heating rate of 20 ºC/min ( ). The pyrolysis process allowed a biochar that meets European standards to be obtained, with a calorific value higher than the initial biomass, which varied between 25.37 MJ/kg and 27.93 MJ/kg. The combustion process proved to be an available technology for the transformation of chemical energy present in biomass into heat, however it results in the emission in high concentration of ultrafine particles, which are harmful to the environment and health. On the other hand, the pyrolysis process proved to be a process that can more widely explored on a large scale, to obtain various energy products, such as biochar, bio-oil and gases, which can be used in several ways. (AU) | |
| FAPESP's process: | 18/03921-3 - Monitoring the emissions generated in the combustion process of the straw/bagasse sugarcane mixture using a laboratory-scale burner |
| Grantee: | Sâmilla Gabriella Coelho de Almeida |
| Support Opportunities: | Scholarships in Brazil - Master |