Avaliação das tecnologias de geração de hidrogênio visando à produção de fertilizantes nitrogenados

Abstract

The use of fertilizers in agriculture results in increased crop productivity and, consequently, in the supply of food for the population. Therefore, as the population increases it is necessary to produce more in smaller spaces and therefore the correct use of fertilizers is crucial. Nitrogen fertilizers are responsible for the growth and development of plants, the nitrogen present in these fertilizers is the macronutrient required in greatest quantities by crops and responsible for the generation of protein. Therefore, firstly, this work listed the main concepts and fundamentals regarding the classification and production of fertilizers. Next, the main aspects of the Brazilian economy were presented in which it was possible to ascertain that Brazil is a large consumer of fertilizers, however, the production volume of nitrogen fertilizers is small, which makes the country dependent on imports. Therefore, the case study involves the analysis of techniques for obtaining hydrogen, which is the main input for the production of nitrogen, as a key to national production and also contributes to environmental goals, such as promoting the circular economy and low carbon. Water electrolysis, alternative sources and anaerobic digestion using industrial waste, such as vinasse and cheese whey, were evaluated, making it a sustainable alternative for the production process. Through the study, it was possible to conclude that electrolysis is in fact a conventional and efficient method for generating hydrogen, however, on an industrial scale the use of water becomes worrying. As a result, alternatives such as the use of groundwater, wastewater and seawater are being evaluated so that the process is economically viable and sustainable. Furthermore, Brazilian studies offer the use of vinasse instead of water in electrolysis as an alternative. The system is still in the pilot scale phase and brings great expectations as a promising alternative. Regarding anaerobic digestion, through the study of the influence of parameters on the process, the highest hydrogen production rate was obtained at a pH maintained between 4.5 and 5.5, substrate organic loading rate between 80 and 90 g DQO/Ld and that the use of co-substrates and process control favors production.