CRITICAL ANALYSIS OF BY-PRODUCTS APPLICATIONS FROM ETHANOL PRODUCTION Amanda Gonçalves Kieling, Iara Janaina Fernandes, Carlos Alberto Mendes Moraes, Cynthia Fleming Batalha da Silveira, Guilherme Luís Roehe Vaccaro, Felipe Demartini, Rosangela Cabrera University of Vale do Rio dos Sinos - UNISINOS/Environmental Engineering Unisinos Avenue, 950, São Leopoldo, zipcode: 93022-000, Brazil amandag@unisinos.br; ijk.fernandes@gmail.com; cmoraes@unisinos.br; cynthiafbs@hotmail.com; guilhermev@unisinos.br; felipedemartini@terra.com.br; rosangela.cabrera@gmail.com ABSTRACT: Due to the reduced availability of nonrenewable natural resources and the climate change caused by increasing the greenhouse effect, studies have been conducted with a view to gradual replacement of current energy sources based on fossil fuels to produce clean fuels from biomass. Within this context, the Brazilian energy matrix showed an 8% reduction in the use of oil and oil products in the last 10 years. Therefore, the abundance of biomass is one of the factors that support for the production of 18% of the country's energy from clean energy. Currently, biomass is valued as a source for energy production with higher growth potential. In Brazil, the source that has emerged is the biomass of sugar cane because of the strong growth of this culture from the years 2000 to ethanol production. An important aspect to be considered in this culture is the generation of by-products such as wastewater, bagasse, leaves and tips, stillage, filter pie and yeast. Among them are worth mentioning bagasse, which due to its calorific value can be applied in power generation. The aim of this work is to present opportunities for using the ethanol by-products as well as technologies to add value to them, considering, the major by-products, bagasse, stillage and fusel oil. In the case of bagasse, this can be used in different industry segments such as paper and cardboard, in manufacturing clusters, the chemical industry as a fertilizer, as an alternative material in civil construction, production of microbial biomass and on animal feed. The main application of stillage may be in irrigation of sugar cane plantation, since its management and beneficiation is controlled adequately. The bagasse ash may be used in civil construction as fine aggregate. Fusel oil can be use as natural herbicide to familiar plantation. Keywords: Sugar cane, ethanol, byproducts, valorization, bagasse. 1 INTRODUCTION According to Silva [1], the industrial stage of fabrication of ethanol is characterized by the environmental aspects of high consumption of water and the generation of high amounts of wastes, where the most important are bagasse and stillage. As a result of that, one of the opportunities, which must be developed to guarantee the energetic and environmental sustainability of the sector, is the valuation of its exceeding materials as by-products. Brazil is the world leader in the production of sugar cane (33.9%), sugar (18.5%) and ethanol (36.4%), and also the world leader in exporting sugar and ethanol [2]. However, only one third of the biomass contained in the sugar cane is used to produce sugar and ethanol [3]. Considering the sugar cane sector in Brazil, it is relevant to point out that the increase of plantation area in Brazil, as well the expansion of ethanol plants contribute to increase the amount of by-products and wastes originated in the agro industry. In this context, Szmrecsányi [4] pointed out that the industries must have a productive diversification to support the volume of generated sub products. The production systems must consider the sustainability and minimization of environmental impacts, so the integral utilization of wastes becomes to be a greater need. Till recently, these materials were considered only as solid wastes, or sometimes as sub- products without commercial value. In this context, the main objective of this work is to carry out a data evaluation and identification of the recycling potential of wastes generated in the industrial production of ethanol, as by-products, however, considering the limitations in terms of their application. To do so, a study was conducted on a Sugar Cane Cooperative which produces ethanol. This case was chosen since it relates social and economical aspects of ethanol production to the environmental issues. 2 LITERATURE REVIEW The by-products from industrial phase of ethanol production are generated as follows. 2.1 Bagasse Recycling Sugar cane bagasse results from the extraction of juice after milling crush, and represents 24% to 30 % of initial mass of sugar cane (humidity of 50%) [5]. All bagasse is commonly used as fuel in boilers from the same industry to generate energy. However, as recently the plant has optimized the boilers and turbines in some plants, it can be estimated that residual bagasse can reach about 20% of total bagasse generated in the production of ethanol, which is causing major problems such as temporary stocking place and environmental pollution. The chemical composition of bagasse can vary according several factors; however its basic composition is water, fibrillar structures (cellulose, hemicellulose e lignine), extractives and inorganic compounds. Bagasse can be divided into two fractions, medular fraction, which has higher amount of ash and cellulose; and fibrillar fraction, with major amount of lignine. Recent researches present the segregation of bagasse as a stage to aggregate value to the by-product, as a way to send the fraction according to its composition to the adequate application for each one. Other relevant application of the bagasse is to produce second generation ethanol. When used for generating energy, bagasse has more energetic value than ethanol, and as a result of that has great potential to be used in the ethanol plants to generate electricity, and also to sell the exceeding energy [6].