AVAILABLE ENERGY FROM SUGAR CANE (Saccharum spp.) BIOMASS RESIDUES

Abstract

The biomass generated from sugar cane (Saccharum spp.) cultivation in México is an important factor in terms of renewable energy. In the 2013-2014 harvest, 52,246508 t of sugar cane were milled in 52 sugar plants, and the energetically usable sugar cane biomass is sugar pulp and tips of the stalks. The sugar pulp represents 30 % of the harvestable stalks and it is the fibrous residue that results from the process used to extract sugar; it is obtained with an average of 50 % moisture, equivalent to 19.5 t ha^-1 of sugar pulp and 3.9 t ha^-1 of fuel. The tips are the plant residue that is left on the field after the harvest and they contain 80 % moisture, representing in average 25 % of the yield, equivalent to 16.8 t ha^-1, that are equivalent to 2.5 t ha^-1 of fuel. These values are determined with a calorimetric pump and for the calculation, the lower calorific power of the biomass was considered; for this purpose, the latent vaporization heat was calculated to obtain the energetic yield, in terms of net energy. The equivalence in usable energy was 57 277 234.6 TJ, considering the tips and the sugar pulp. The process used to obtain sugar can be carried out without using fossil fuels or additional energy to what is produced by the sugar pulp, since the mechanical energy consumption is 25–30 kWh t^-1 of sugar cane and vapor consumption for the process is 450-550 kg t^-1 of the sugar cane. Thus, the equivalent energetic value obtained from one ton of sugar cane ranges from 1.15 to 1.31 barrels of oil; therefore, the total available energy value in the harvest of reference would be 9 870 441.88 barrels of petroleum.