Tecnologia alternativa para a secagem de grãos com efeito técnico inovador que maximiza o desempenho e minimiza o risco de incêndios

Abstract

Grain production in Brazil rose from 114 to more than 238 million of tons/year from 2004 to 2017, ranking the country as one of the biggest producers in the world. The future harvest perspective indicates a production growth to 301,8 million grain tons/year. The reduction of humidity is necessary in the processing and storage, before their final destination. In most cases, the process using grain drying furnaces shows a series of technical restrictions that it doesn’t always guarantee desirable efficiency, safety (due to high level of risk of fire) and quality. Given this scenario, the essay aims the development of an alternative technology to the grain drying with innovative technical effect that maximizes the development and minimizes the risk of fire. The methodology embraces eight stages: 1) characterization of the study element; 2) characterization of the grain and analysis of variables in the drying process; 3) search of methods, processes and traditional drying technologies; 5) planning, forecast and building of a prototype; 6) operationalization and tests of the equipment; 7) systematization of the results; 8) requirement evaluation for intellectual protection. The search resulted in a Project and construction of a modular equipment (grain drying prototype) with innovative characteristics on the drying area, on the indirect transference of heat to the grains, on the air dehumidifying module and on the controlling system of the process that operates with maximum development and minimum risk of fire. The heat indirect changing system of the drying tower registered working temperature reduction average of 36%, compared to the heat direct changing systems of traditional equipment. The reuse of heated gases from the drying tower provided efficiency rise of 17% in the air heating. During the grain drying tests, the dehumidifying module obtained average rate of relative air humidity reduction of 76%. The regeneration process of the absorbing agent (Al_2 O_3) in the hot chamber allowed the maintenance of stable air humidity used in the drying process, generating average amplitude of only 3 percentage points. With an average temperature of 72 ºC in the first heating exchanger of the drying tower, and with average humidity of air drying in 17%, there was average reduction of -0,5% (wet basis) of grain humidity on the interval of 25 minutes. This way, the developed technology is shown as an alternative for non-conventional grain drying in great conditions of operation, certifying the quality of the product in a reduced risk of fire environment.