The production of large quantities of paint sludge is a serious environmental problem. This work evaluates the use of pyrolysis reaction as a process for deactivating paint sludge that generates a combustible gas phase, a solvent liquid phase and an inert solid phase. These wastes were classified into three types: water-based solvent (latex resin) and solvents based on their resins (alkyd and polyurethane). An electrically heated stainless steel batch reactor with a capacity of 579 mL and a maximum pressure of 30 atm was used. Following the reactor, a flash separator, which was operated at atmospheric pressure, partially condensed and separated liquid and gas products. Pressure and temperature were monitored on-line by a control and data acquisition system, which adjusted the heating power supplied to the pyrolysis reactor. Reactions followed an experimental design with two factors (reaction time and temperature) and three levels (10, 50 and 90 minutes; 450, 550 and 650°C). The response variables were liquid and solid masses and net heat of combustion. The optimal operational range for the pyrolysis process was obtained for each response variable. A significant reduction in total mass of solid waste was obtained
This study aimed to evaluate the extraction of Corymbia citriodora (Hook.) K.D.Hill and L.A.S.Johnson essential oil by steam distillation under reduced pressure. Yield and composition of the essential oils obtained at different system pressures were analyzed. System pressure had a significant influence on essential oil yield, resulting in a reduction of 78.6% when the pressure was reduced from 690 Torr to 240 Torr. There were also changes in essential oil composition, with an increase in citronellol content (oxygenated monoterpene). However, the major compound (citronellal) remained at a high content in all tests. Regarding the extracted mass of the major compounds (citronellal, citronellol), there was a significant reduction for all when the system pressure was reduced. Although the reduction in the pressure of the system caused a reduction in oil yield, it was possible to carry out the steps of extraction and purification of the major compound simultaneously. Reduced pressure extraction may decrease process time, increasing its efficiency and reducing costs in the extraction of essential oils.
A suinocultura é uma atividade que representa riscos ao meio ambiente, devido à quantidade de dejetos gerados. Um suíno com um porte de 25 a 100 kg produz aproximadamente 7 litros de dejetos líquidos/dia. A utilização de biodigestores para o tratamento de dejetos suínos reduz os poluentes e ainda produz biogás. Os resultados deste estudo referem-se ao projeto de uma unidade geradora de biometano para uma granja de 250 suínos, com uma vazão de 1,75 m³/dia de dejetos. Nesta unidade os dejetos são encaminhados para um reator UASB com altura de 6 m e diâmetro de 2,005 m. No reator é realizada a digestão anaeróbia operando com uma temperatura de 30 a 35°C. A COV adotada foi 3,35 kgDQO/m³.dia e a concentração de DQO solúvel 36,26 kgDQO/m³, com estes parâmetros foi obtido TDH de 259,75 horas e uma eficiência de remoção de DQO e DBO de 90,29% e 95,66% respectivamente. A produção volumétrica de biogás gerada no reator foi 22,54 m³/dia. Para remover o H₂S e o CO₂ foi projetado um tanque de dessulfurização de 145,54 mm de altura e 83,17 mm de diâmetro, aplicando como agente dessulfurante uma lama de cal com vazão de 458 mL/dia, na qual é borbulhado o biogás. Após, o biogás dessulfurado segue para uma coluna de adsorção de 1,286 m de altura e 64,3 mm de diâmetro, utilizando como adsorvente 1.721,95 g de carvão vegetal, para fazer a remoção da umidade.
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