Characteristics and synergistic effects of co-combustion of carbonaceous wastes with coal

• Published in: Waste management (Elmsford) 2018-01, Vol.71, p.192-199
• Main Authors: Onenc, Sermin, Retschitzegger, Stefan, Evic, Nikola, Kienzl, Norbert, Yanik, Jale
• Format: Article
• Language: English
• Subjects: Co-combustion; NOx emission; Poultry litter; Scrap tires; SO2 emission
• ISSN: 0956-053X; 1879-2456
• DOI: 10.1016/j.wasman.2017.10.041

•Addition of chars to lignite caused lowering of combustion reactivity.•Use of PLC in fuel blends reduces SO2 emission and sulphur compounds in aerosol.•In co-combustion, NOx emissions were not proportional to the mixing ratio of fuels.•Ash melting temperatures for PLC and PLC containing blends are higher than 1000 °C. This study presents combustion behavior and emission results obtained for different fuels: poultry litter (PL) and its char (PLC), scrap tires (ST) and its char (STC) and blends of char/lignite (PLC/LIG and STC/LIG). The combustion parameters and emissions were investigated via a non-isothermal thermogravimetric method and experiments in a lab-scale reactor. Fuel indexes were used for the prediction of high temperature corrosion risks and slagging potentials of the fuels used. The addition of chars to lignite caused a lowering of the combustion reactivity (anti-synergistic effect). There was a linear correlation between the NOx emissions and the N content of the fuel. The form of S and the concentrations of alkali metals in the fuel had a strong effect on the extent of SO2 emissions. The use of PL and PLC in blends reduced SO2 emissions and sulphur compounds in the fly ash. The 2S/Cl ratio in the fuel showed that only PLC and STC/PLC would show a risk of corrosion during combustion. The ratio of basic to acidic oxides in fuel indicated that ST, STC and STC/LIG have low slagging potential. The molar (Si+P+K)/(Ca+Mg) ratio, which was used for PL, PLC and PLC containing blends, showed that the ash melting temperatures of these fuels would be higher than 1000 °C.