Co-combustion of wood chips with the biomass obtained from the physico-chemical treatment of slaughterhouse wastewater for steam generation - A case study

摘要

The worldwide demand of energy and the greenhouse effect induced by anthropogenic activities make the energy question a prioritary subject in the global politics agenda. Co-combustion of wastes and primary fuels is an attractive option to increase the use of renewable fuels. The aim of this paper is to evaluate the utilization of slaughterhouse biomass (B) obtained from the physico-chemical treatment of the slaughterhouse wastewater as an energy source, taking into account its physico-chemical properties and the flue gas composition resulted in its co-combustion with wood chips (W) in a mixture ratio of W:B, 9:1 (WB) in weight. The gaseous pollutants concentrations were compared to current Brazilian and international environmental legislation. The CO observed for W combustion was higher than all the limit concentrations taken into account that regulate this pollutant, while for the WB combustion test the CO was only in accordance to the limits settled by Brazilian regulations CONAMA 382/06 and SEMA. NO_x in the co-combustion test was above the two more stringent limits, settled by 17.BlmSchV (24 h) and 17.BlmSchV (24 h; 50 MW). SO_2 was higher than USEPA and 17.BlmSchV (24 h) limits in W and WB combustion tests. The feedstock homogeneity and composition are important parameters when a mixture is considered to avoid variation of the flue gas composition, mainly when one of the components of the mixture presents high concentration of a constituent that can potentially originate toxic gaseous pollutants. In order to produce low amounts of pollutants, the combustion process control must be optimized to achieve pollutant emission requirements considering the combustion technologies applied, the kind of biomass used and its thermal behaviour.