Produção de hidrogênio a partir da vinhaça

• Autor(a) principal: Corrêa, Renata Melo Bonatti
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/3803
• topic: Hidrogênio; Produção; Vinhaça; Produção de hidrogênio; Digestão anaeróbia; Eletrólise; Brasil.; Hydrogen production; Vinasse; Anaerobic digestion; Electrolysis; Brazil.; Engenharias; Engenharia Química

The stillage is the industry effluent sugar and alcohol produced by fermentation of molasses and / or the juice of sugar cane to produce ethanol. In this process are generated 10-15 liters of vinasse, for each liter of ethanol produced. The organic material in the stillage is basically in the form of organic acids, giving a pH between 3.7 and 5.0. It is a liquid with a very high concentration of organic compounds (ranging from 22,000 mg L-1 -98000 mg L-1) and with many nutrients from the sugar cane from which it originated, which means it can not be dropped directly into water bodies receivers because, otherwise, would have major environmental impacts. The organic matter present in raw sewage poses a low cost to produce alternative fuels. Thus, this work aimed to study the processes of anaerobic digestion of stillage and electrolysis in order to produce hydrogen. Tests of anaerobic digestion were performed on small-scale batch reactors. The experiments were performed in glass reactors with a capacity of 100 mL, which were inserted in plastic syringes for the measurement of biogas. The experiments lasted 49, 70, 99 and 105 days and were performed at 28 ° C, under conditions of presence and absence of agitation (150 rpm). The vinasse was inoculated in the proportions of 10, 20, 30 and 40% with sewage sludge. The pure vinasse was also evaluated. The main parameters were monitored: pH, volatile acidity, chemical oxygen demand (COD), total solids and total volatile solids. During this period, production of hydrogen was analyzed by a gas chromatograph Thermo Finnigan - Trace GC. In the study of electrolysis was used a cylindrical reactor bench with capacity of 0.8 L with an outlet to collect the gas produced, and the negative electrode made of stainless steel 304, 300 mm in height and 58 mm internal diameter and the positive electrode of aluminum, with 230 mm height, 12 mm in diameter, and with plates of the same material, measures 35 x 35 each, embedded in the electrode parallel to one another to increase the contact surface. The system was powered by a source of current. The system temperature was maintained at 25 ° C through the jacketing and a thermostat. The following parameters were varied during the tests: voltage (V), current (A) and dilution of vinasse. The gas produced was removed through a sealed plastic bag, with only a hole for entry of gas through a hose, and analyzed on a Thermo Finnigan gas chromatograph - Trace GC. The effects of the following parameters were evaluated: pH, conductivity, color, COD and total dissolved solids (TDS). Among the main results obtained in the anaerobic digestion process, one can say that the higher production of hydrogen gas in the test was 100% vinasse in a collection, with production of 6.25 mL of H2 over a period of 55 days. In collecting three tests without agitation obtained higher hydrogen production compared to tests with agitation. As the percentage increase of inoculum in the tests with agitation, there was also an increased production of hydrogen. It can be said about the production of hydrogen made by anaerobic digestion, which were not achieved the desired results. The main results obtained in the process of electrolysis showed that the higher production of hydrogen, 78.93%, was obtained by applying currents of 3 A and voltage of 10 V. With the dilution of the stillage, the highest H2 production was 72.68% in 30% water.