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Abstract(s)
O presente trabalho foi desenvolvido no âmbito da disciplina de Dissertação/Estágio (DIEST), para a conclusão do Mestrado em Engenharia Química, no ramo de Energia e Biorrefinarias. O trabalho foi realizado na direção fabril da empresa BA Vidro, na Divisão e Composição e Fusão, em Avintes, onde é feita a produção de embalagens de vidro, nomeadamente, garrafas de vidro para a indústria alimentar.
O trabalho desenvolvido teve como objetivo a avaliação energética de um dos fornos de fusão (AV5) da empresa e a determinação do ponto ótimo entre o consumo de gás atural e eletricidade. Este forno corresponde ao maior consumidor energético do processo de produção de embalagens.
Para ser alcançado o objetivo proposto, procedeu-se inicialmente ao estudo das características de um forno de fusão. Posteriormente, foi realizada uma avaliação energética do AV5 relativa ao ano de 2016, com a realização do balanço mássico e energértico. Neste, foi obtido um valor de perdas térmicas de 12 423 883 kW no total do ano. A partir do balanço de energia, determinou-se a poupança energética ao nível de gás natural, variando a quantidade de excesso de ar. No ano estudado foi utilizado um excesso de 24% com um volume de gás natural de 0,453 m3/s. Foi considerado um excesso de 20%, 15% e o ar em proporções estequiométricas. Para 20% obteve-se o menor volume de gás natural, 0,220 m3/s, ou seja, corresponde a uma poupança de 20 131 m3/dia.
De seguida, foram determinados os diferentes indicadores de fusão, o consumo específico de energia, a intensidade carbónica e o custo específico de fusão. Para o primeiro, o valor médio anual foi de 0,099 tep/ton, para o segundo obteve-se valor médio anual de 2348 kgCO2/tep e, por último, 95,8 €/ton.
Foram analisadas as variáveis predominantes no processo de fusão, com o intuito de ser avaliada a sua influência. As diferentes variáveis analisadas foram, a produção de vidro fundido (tiragem), a percentagem de vidro reutilizado (casco) como matéria-prima, o poder calorífico do gás natural e a humidade relativa do ar. A influência destas variáveis foi analisada com base em alterações no consumo específico de energia e no custo específico de fusão. A tiragem apresenta um intervalo entre 311 e 461 toneladas diárias e a percentagem de casco um intervalo entre 55 e 70%.
Relativamente à influência da incorporação de casco, o melhor consumo específico de energia foi obtido para o intervalo 67-70% de casco, para uma tiragem de 451-456 toneladas. Foi possível também concluir que o poder calorífico inferior apresenta uma grande influência no consumo específico de energia, contrariamente à humidade relativa do ar. Dos diferentes consumos energéticos avaliados, o gás natural e a eletricidade, o que apresenta maior variação e influência no processo é o gás natural.
Para cada percentagem de casco, foram obtidas relações entre a quantidade de gás natural e eletricidade e a tiragem de vidro fundido. Para percentagens superiores a 62% de casco, relativamente ao consumo energético, o mais vantajoso é utilizar elevadas tiragens. Até 62%, o mais vantajoso é a utilização de tiragens inferiores.
Por fim, foi utlizada a ferramenta Solver para a obtenção de equações da reta, que relacionam a quantidade de gás natural e de eletricidade em função da tiragem, para diferentes percentagens de vidro reutilizado.
This current project was developed within the scope of the Dissertation/Internship (DIEST) discipline for the conclusion of the Master in Chemical Engineering – Energy and Biorefinery. The work was carried out in the factory direction of the company BA Vidro in the Division of Composition and Fusion, located in Avintes, where the production of glass containers is made, namely glass bottles for the food industry. The main goal of the project developed was the energy evolution of the melting furnace (AV5) of the company and the determination of the optimal point between the consumption of natural gas and the power. This furnace is the major energy consumer in the process of packaging production. For the initial goal to be achieved the characteristics of a melting furnace were studied. Subsequently an energy evaluation of the AV5 in the year of 2016 was performed, with the determination of the mass and energy balance. In this, a value of thermal losses of 12 423 883 kW were obtained in total for the year 2016. From the energy balance, energy savings were determined at the level of natural gas, by varying the amount of excess air. In the studied year, an excess of 24% was used with a natural gas volume of 0,453 m3/s. An excess of 20%, 15% and air were considered in stoichiometric proportions. For 20% the lowest volume of natural gas was obtained, 0,220 m3/s, that is, it corresponds to a saving of 20 131 m3/day. Next, the different melting indicators were examined, such as the specific energy consumption, the carbon intensity and the specific cost of melting. For the former, the average annual value was 0,099 tep / ton, for the latter the average annual value was 2348 kgCO2 / tep and, lastly, 95.8€/ton. All the different predominant variables of the melting process were analysed to avail its influence. The different analysed variables were the production of melting glass (drawing), the percentage of reused glass (hull) as raw material, the natural gas calorific power and the relative humidity of the air. The influence of these variables was analysed based on changes in the specific energy consumption and the specific cost of melting. The drawing ranges from 311 to 461 tonnes per day and the hull percentage is in the range of 55 to 70%. Regarding the influence of the hull incorporation the best specific energy consumption obtained was 67-70% hull range for a drawing range of 451-456 tonne. It was also possible to conclude that the lower calorific value has a great influence on the specific consumption of energy opposing to the relative humidity of the air. Of the different energy evaluation, the natural gas and the electricity, the one that represents the biggest influence and variation on the process is the natural gas. For each percentage of hull, it was obtained a relation between the quantity of natural gas and electricity and the drawing of molten glass. For percentages exceeding 62% of hull, comparing to energy consumption, the most advantageous is to use high runs. Up to 62%, the most advantageous is the use of lower runs. Lastly, the Solver tool was used to obtain equations with related the quantity of natural gas and electricity in function of the run, for different percentages of reused glass.
This current project was developed within the scope of the Dissertation/Internship (DIEST) discipline for the conclusion of the Master in Chemical Engineering – Energy and Biorefinery. The work was carried out in the factory direction of the company BA Vidro in the Division of Composition and Fusion, located in Avintes, where the production of glass containers is made, namely glass bottles for the food industry. The main goal of the project developed was the energy evolution of the melting furnace (AV5) of the company and the determination of the optimal point between the consumption of natural gas and the power. This furnace is the major energy consumer in the process of packaging production. For the initial goal to be achieved the characteristics of a melting furnace were studied. Subsequently an energy evaluation of the AV5 in the year of 2016 was performed, with the determination of the mass and energy balance. In this, a value of thermal losses of 12 423 883 kW were obtained in total for the year 2016. From the energy balance, energy savings were determined at the level of natural gas, by varying the amount of excess air. In the studied year, an excess of 24% was used with a natural gas volume of 0,453 m3/s. An excess of 20%, 15% and air were considered in stoichiometric proportions. For 20% the lowest volume of natural gas was obtained, 0,220 m3/s, that is, it corresponds to a saving of 20 131 m3/day. Next, the different melting indicators were examined, such as the specific energy consumption, the carbon intensity and the specific cost of melting. For the former, the average annual value was 0,099 tep / ton, for the latter the average annual value was 2348 kgCO2 / tep and, lastly, 95.8€/ton. All the different predominant variables of the melting process were analysed to avail its influence. The different analysed variables were the production of melting glass (drawing), the percentage of reused glass (hull) as raw material, the natural gas calorific power and the relative humidity of the air. The influence of these variables was analysed based on changes in the specific energy consumption and the specific cost of melting. The drawing ranges from 311 to 461 tonnes per day and the hull percentage is in the range of 55 to 70%. Regarding the influence of the hull incorporation the best specific energy consumption obtained was 67-70% hull range for a drawing range of 451-456 tonne. It was also possible to conclude that the lower calorific value has a great influence on the specific consumption of energy opposing to the relative humidity of the air. Of the different energy evaluation, the natural gas and the electricity, the one that represents the biggest influence and variation on the process is the natural gas. For each percentage of hull, it was obtained a relation between the quantity of natural gas and electricity and the drawing of molten glass. For percentages exceeding 62% of hull, comparing to energy consumption, the most advantageous is to use high runs. Up to 62%, the most advantageous is the use of lower runs. Lastly, the Solver tool was used to obtain equations with related the quantity of natural gas and electricity in function of the run, for different percentages of reused glass.
Description
Keywords
Fusão Energia Eletricidade Gás Natural Otimização Casco Melting Energy Electricity Natural Gas Optimization Cullet