Utilização de linter hidrolisado como fonte de energia

Abstract

So as to obtain linter from cotton seeds originating from the chemical delinting process, diluted sulfuric acid was used. This was mixed with cotton seeds originating from the ginning process. The need for removal of the linter remaining on the cotton seeds facilitates sewing as this allows for adequate flow, and so avoids an excess of seeds being placed in the same spot during sewing. The delinting process was carried out at the Cotton Tecnologia de Sementes Company obeying the following stages: 1) mixture of sulfuric acid at concentration of 11 to 12% with the seeds covered with linter; 2) transport of material using conveyor buckets to a worm helix which feeds a reactor; 3) reaction of linter with H2SO4 in perforated rotating drum reactor in which the warm air flowing at a temperature of 120°C, while the reaction time is of 1 h and 15 minutes (at this stage the linter comes off the seed tegument or outer husk); 4) the hydrolyzed linter is transported by exhaust (exit) air and separated in a cyclone separator; 5) at the unloading of the cyclone separator the residue is transported by a worm helix and receives sodium hydroxide at 5 % in the proportion of 20 % mass, and so allowing for the partial neutralization of the sulfuric acid. The neutralized linter was transformed in briquettes at the Maeda S.A company (Itumbiara - GO). The screen analysis showed that the average Sauter diameter of the hydrolyzed and neutralized linter was 0,22 and 0,17 mm, respectively. The density of the hydrolized and neutralized linter was 630 kg/m3 and 520 kg/m3, respectively and the briquettes developed had densities of 1480 kg/m3 and 1580 kg/m3, respectively. The neutralized linter briquettes were analyzed chemically and the following results were obtained (dry base): 82,95 % of volatile matter; 16,57 % of fixed carbon; 0,48 % of ashes; 0,25 % of sulfur. The superior and inferior calorific value of the neutralized linter briquettes were (dry base): 17.432 kJ/kg and 16.095 kJ/kg, respectively. The briquettes were burned, the gases were analyzed and calculated the concentration of SO2 (172,4 mg/m3) emitted in the combustion gases of the neutralized linter briquettes. This concentration was inferior to the CONAMA (280 mg/m3) and CETESB (262 mg/m3) parameters which places it within the Brazilian legislation requirements.