Co-combustion of high and low ash lignites with raw and torrefied biomass under air and oxy-fuel combustion atmospheres

Co-combustion characteristics of high and low ash lignites blended with raw and torrefied pine woodchips were studied by Thermogravimetric Analyzer (TGA) under air and oxy-fuel conditions. The lignites were blended with biomass samples at the mass fraction of 50/50 wt.%. Three heating rates of 10, 20, and 40 degrees C/min were chosen, and the characteristic temperatures, including initial, ignition, and burnout temperatures, were obtained. In order to estimate the activation energies of the co-combustion of the blends, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, and Friedman kinetic methods were employed. Additionally, to assess the summative behavior of the fuel blends, the relative error as a degree of synergism was calculated based on the difference between theoretical and experimental DTG profiles. It was seen that co-combustion of torrefied biomass with the low ash Orhaneli lignite in air resulted in the average relative error of 21.41%, indicating the maximum synergism for the blend. This value was 9.59% under oxy-fuel combustion atmosphere. Blending torrefied biomass with the high ash Soma lignite resulted in average relative errors of 1.34% and 1.45% under air and oxy-fuel combustion atmospheres showing an insignificant synergetic effect. An improvement in combustion performance was noticed under oxy-fuel combustion conditions. The average activation energy values for the blend of torrefied biomass and Orhaneli lignite were 54.47 and 112.48 kJ/mol under air and oxy-fuel combustion atmospheres, which were lower than that of the parent fuels indicating higher reactivity of the blends. This trend was not seen for Soma lignite. The associated uncertainty values for the FWO method were in the range of 3.57% to 12.45% making it a proper tool for obtaining the kinetic parameters.


Co-firing of pine chips with Turkish lignites in 750 kWth circulating fluidized bed combustion system
Atımtay, Aysel; Unlu, Alper; Engin, Berrin; Varol, Murat; OLGUN, HAYATİ; Atakül, Hüsnü (2017-01-01)
Two Turkish lignites which have different sulfur levels (2-2.9% dry) and ash levels (17-25% dry) were combusted with a Turkish forest red pine chips in a 750 kW-thermal capacity circulating fluidized bed combustor (CFBC) system. The combustion temperature was held at 850 +/- 50 degrees C. Flue gas emissions were measured by Gasmet DX-4000 flue gas analyzer. Two lignites were combusted alone, and then limestone was added to lignites to reduce SO2 emissions. Ca/S = 3 was used. 30% percent of red pine chips we...
Co-combustion of biocoal and lignite in a circulating fluidised bed combustor to decrease the impact on global warming
Keivani, Babak; OLGUN, HAYATİ; Atımtay, Aysel (2019-01-01)
This work covers co-combustion of biocoal obtained from red pine wood chips with Orhaneli lignite in a 30 kW-thermal capacity circulating fluidised bed combustor (CFBC) system in air and oxygen-enriched atmosphere. The combustor was of 108 mm inside diameter and 6 m height. The combustion temperature was held at 850+50 degrees C. Oxygen enriched combustion tests were carried out at different ratios of lignite and biocoal mixtures. Biocoal share in the fuel mixture was increased up to 50% by wt. It was found...
Combustion behaviour of Turkish lignite in O-2/N-2 and O-2/CO2 mixtures by using TGA-FTIR
Selçuk, Nevin (2011-03-01)
The pyrolysis and combustion behaviour of a low calorific value Turkish lignite with high sulphur and ash content in air and oxy-fuel conditions were investigated by using non-isothermal thermo-gravimetric method (TGA) coupled with Fourier-transform infrared (FTIR) spectrometer. Pyrolysis tests were carried out in nitrogen and carbon dioxide environments which are the main diluting gases of air and oxy-fuel environment, respectively. Pyrolysis results show that weight loss profiles are almost the same up to...
TGA and kinetic study of different torrefaction conditions of wood biomass under air and oxy-fuel combustion atmospheres
Barzegar, Ramin; Yozgatlıgil, Ahmet; OLGUN, HAYATİ; Atımtay, Aysel (2020-06-01)
Combustion and oxy-fuel combustion characteristics of torrefied pine wood chips were investigated by Thermogravimetric Analysis (TGA). Three torrefaction temperatures (250, 300, and 350 degrees C) and two residence times (15 and 30 min) were considered. Experiments were carried out at three heating rates of 10, 20, and 40 degrees C/min. The isoconversional kinetic methods of FWO, KAS, and Friedman were employed to estimate the activation energies. The assessment of uncertainty in obtaining the activation en...
Investigation of combustion kinetics of treated and untreated waste wood samples with thermogravimetric analysis
Yorulmaz, Sema Yurdakul; Atımtay, Aysel (2009-07-01)
In the present study, combustion mechanisms, thermal kinetics, and phases of combustion were investigated for waste wood samples (untreated pine and treated MDF, plywood and particleboard). Waste wood samples were combusted in air at 10, 20 and 30 degrees C/min heating rates in TGA. The results of TG analysis have shown that thermal decomposition of treated samples takes place at lower temperatures as compared to the untreated pine sample because of the catalyzing effects of the chemicals in the samples. Th...
Citation Formats
R. Barzegar, A. Yozgatlıgil, and A. Atımtay, “Co-combustion of high and low ash lignites with raw and torrefied biomass under air and oxy-fuel combustion atmospheres,” ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS, pp. 0–0, 2022, Accessed: 00, 2022. [Online]. Available: