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The ignition behavior of coal particles was studied through an enhanced numerical model, combined with experimental investigations in a visual drop tube furnace in the temperature range of 1100–130...

The ignition and combustion behavior of pulverized coal was studied with respect to coal rank in a custom-designed visual drop tube furnace. The results showed that low-rank coals were ignited in a shorter time, mainly due to the presence of larger amounts of functional groups, while the ignition delay time of high-rank coals was longer. With increasing temperature and particle size, the ignition mode of coals shifted from heterogeneous into homogeneous, which was related to the increased yield of volatile matter. The chemical percolation devolatilization analysis results showed a clear relationship between the yield and composition of volatile matter and the amount and type of functional groups in coal. In addition, the tar yield was consistent with the amount of aliphatic hydrocarbons and the length of aliphatic chains, which explained the tailing combustion mode of the bituminous coal. The findings of the study showed that the yield and composition of volatiles in coal had a significant impact on the ignition behavior, which depended on the composition of functional groups, particle size, and the combustion environment.

Potassium hydroxide-impregnated char sorbents (KOH/char) prepared via an ultrasonic-assisted method were used for SO2 removal from flue gas. The desulfurization experiment was analyzed using a fixed-bed reactor under 40–150 °C temperature range, using simulated flue gas. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) were used to analyze both the chemical and physical characteristics of the sorbents. The analyzed results exposed that the complete elimination of SO2 from flue gas was achieved when using the char/KOH sorbent with a mass ratio of char to KOH of 11:1. It was noted that temperature had a substantial influence on the desulfurization performance with sulfur capacity maximized at 100 °C. Experimental results also revealed that a small amount of O2 present in the solvent could improve the SO2 removal efficiency of the sorbent. The analyzed XRD patterns showed that K2SO4 was the main desulfurization product, which was consistent with the SEM/EDS analysis. The experimental results were well-described with the Lagergren first-order adsorption kinetics model with the activation energy (Ea) of the SO2 adsorption by KOH/char sorbent of 20.25 kJ/mol.

Activated carbon has been used commercially to remove SO2 from coal combustion flue gas. However, the role of inherent CaO in activated carbon is uncertain. In this study, the adverse effects of inherent CaO in the activated carbon derived from coconut shell (CSAC) on its desulfurization performance were systematically studied at the temperature range of 60-100 °C in a fixed-bed reactor. The solid sorbent samples were analyzed using scanning electron microscopy, X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller analysis. The flue gas compositions were analyzed by using an online flue gas analyzer. The experimental results showed that the inherent CaO had a profoundly adverse influence on the desulfurization capacity and efficiency of CSAC at all of the temperatures studied. This adverse influence was clearly identified by a comparison of the desulfurization performance of the raw CSAC to those of the acid-washed CSAC samples. It was found that the removal of the inherent CaO from CSAC using a pretreatment of HCl aqueous solution led to an increase in the desulfurization capacity of 41.7%. The adverse effects were attributed to the conversion of CaO into dihydrate calcium sulfate whiskers which formed solid crystals that blocked the micropores of the CSAC particles.

A series of Mn0.15Fe0.05/fly-ash catalysts have been synthesized by the co-precipitation method using coal fly ash (FA) as the catalyst carrier. The catalyst showed high catalytic activity for low-temperature selective catalytic reduction (LTSCR) of NO with NH3. The catalytic reaction experiments were carried out using a lab-scale fixed-bed reactor. De-NOx experimental results showed the use of optimum weight ratio of Mn/FA and Fe/FA, resulted in high NH3-SCR (selective catalytic reduction) activity with a broad operating temperature range (130&ndash, 300 &deg, C) under 50000 h&minus, 1. Various characterization methods were used to understand the role of the physicochemical structure of the synthesized catalysts on their De-NOx capability. The scanning electron microscopy, physical adsorption-desorption, and X-ray photoelectron spectroscopy showed the interaction among the MnOx, FeOx, and the substrate increased the surface area, the amount of high valence metal state (Mn4+, Mn3+, and Fe3+), and the surface adsorbed oxygen. Hence, redox cycles (Fe3+ + Mn2+ &harr, Mn3+ + Fe2+, Fe2+ + Mn4+ &harr, Mn3+ + Fe3+) were co-promoted over the catalyst. The balance between the adsorption ability of the reactants and the redox ability can promote the excellent NOx conversion ability of the catalyst at low temperatures. Furthermore, NH3/NO temperature-programmed desorption, NH3/NO- thermo gravimetric-mass spectrometry (NH3/NO-TG-MS), and in-situ DRIFTs (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) results showed the Mn0.15Fe0.05/FA has relatively high adsorption capacity and activation capability of reactants (NO, O2, and NH3) at low temperatures. These results also showed that the Langmuir&ndash, Hinshelwood (L&ndash, H) reaction mechanism is the main reaction mechanism through which NH3-SCR reactions took place. This work is important for synthesizing an efficient and environmentally-friendly catalyst and demonstrates a promising waste-utilization strategy.

Catalytic graphitization of biomass-based carbon has been used to synthesize graphene nanostructures with extraordinary electrochemical properties. To further improve the structural properties of these graphene nanostructures, it is critical to gain a deeper understanding of the formation mechanism and influence of process variables on the structural features of the resulting material. Here, we report the impact of various parameters such as catalyst loading, temperature, holding time, and catalyst salt precursor on the low-temperature catalytic graphitization of activated carbon (AC). Quantitative X-ray diffraction (XRD) analysis results show that at 20 wt% catalyst loading, reaction temperature of 1400 °C, and holding time of 30 min, a complete graphitization of amorphous carbon was achieved. In situ XRD and transmission electron microscopy (TEM) results indicated that the dissolution-precipitation and metal-induced graphitization are the primary mechanisms under which graphitized carbon was formed. Furthermore, it was found that the rate of graphitization under microwave irradiation is significantly higher than conventional heating, mainly owing to the enhanced precipitation of graphitic carbon caused by both carbon saturation and temperature fluctuation of the catalyst particles.

A series of novel iron-based deep eutectic solvents (DESs) as denitrification sorbents were evaluated to capture NO from simulated flue gases. The application of Fe(II) EG-ChCl DESs demonstrated the efficiency of absorption performance with the complete removal of NO and zero secondary pollution. In this study, mixtures of Ferric chloride (FeCl2), Ethylene glycol (EG), and Choline chloride (ChCl) were prepared using Fe(II) EG-ChCl DESs. Experimental results showed that the best performance for denitrification was achieved when DES solutions were treated at 60 °C, the gas flow rate of 50 mL/min, 5% partial pressure of steam, and the concentration of Fe(II) was 0.1 mol/L. Furthermore, excellent stability for denitrification was observed for the Fe(II) EG-ChCl DESs during five absorption–desorption cycles. The absorption reaction of Fe(II) EG-ChCl DESs maintained a first-order reaction kinetics with a reaction rate constant of 1.1 × 106 (L/mol·s) for the denitrification reaction. The FT-IR result indicated that there was a chemical interaction between Fe2+ and NO, and Fe2+ was the absorptive active species.

Four hydrogen bond acceptors (HBAs) with different carbon chain length substituents, including methyl-triphenyl phosphonium bromide (MTPB), ethyl-triphenyl phosphonium bromide (ETPB), propyl-triphenyl phosphonium bromide (PTPB), and butyl-triphenyl phosphonium bromide (BTPB), combined with ethylene glycol (EG) were developed to synthesize four low-viscosity deep eutectic solvents (DESs). In this study, the effect of different substituents in DESs on low-concentration SO2 absorption was systematically studied at 30–70 °C. Experimental results show that the EG-MTPB DES has a higher SO2 absorption capacity and a lower viscosity than other DESs. The reason for the higher SO2 absorption capacity of EG-MTPB DES was described by viscosity experiments and quantum chemical calculations. It was shown that the strong polarization ability of the CH3 group promotes the absorption of SO2 by DESs. 1H NMR and FTIR results indicated that chemical interactions primarily exist between the S of SO2 and Br, and the O of SO2 and the H atom of EG form hydrogen bonds. The density functional theory (DFT) results also confirm that the charge of the Br atom migrated to the S atom. Also, thermostability and regeneration experiments showed that the EG-MTPB DES exhibits good stability and can thus be used for industrial flue gas desulfurization.

To better understand the role of microwave and the mechanisms of thermal cracking and catalytic reforming of lignocellulosic bio-oils, this study compares the difference in the reaction characteristics between microwave-assisted and conventional heating of representative bio-oil model compounds. Syringol and guaiacol were selected as bio-oil model compounds. The effects of the heating method on the conversion of the model compound and the yield and composition of products were systematically investigated in the temperature range of 600–700 °C. The results showed that high reaction temperature and microwave-assisted heating favoured the conversion of model compounds, and the conversions of syringol were generally higher than those of guaiacol under the same conditions (temperature, heating method). The heating method was found to greatly influence the yield and composition of products. The bio-oil obtained from conventional thermal cracking of model compounds contained phenolics, aromatic hydrocarbons, aryl alkyl ethers, and oxygen-containing heterocyclic compounds. In contrast, microwave-induced polarisation of poorly stable methoxy groups promotes the formation of phenolics, the concentration of the phenolic in the guaiacol and syringol bio-oil reached 62.5–66.17 area% and 85.18–87.65 area%, respectively, in the temperature range of 600–700 °C. Catalytic reforming of model compounds showed that activated carbon catalyst drastically promoted the phenol formation, particularly under microwave-assisted heating, the phenol concentration reached 93.9–97.97 area% in bio-oil during catalytic reforming of guaiacol. The formation of electron-hole pairs on the active metal sites induced by microwave radiation possibly enhanced the demethoxylation to selectively generate phenol due to the strong electron-donating ability of the methoxyl group. Microwave-assisted catalytic reforming of the model compounds was also beneficial for H2 formation because of the direct dehydrogenation of methyl radicals and the gas-phase reactions. The H2 concentrations of 81.07–82.41 vol.% and 75.2–79.16 vol.% were obtained during microwave-assisted catalytic reforming of guaiacol and syringol, respectively.

Graphene composite materials have attracted significant attention for green energy storage systems due to their excellent electrochemical properties. We report a low-cost and environmentally friendly approach for synthesis of 3D multilayer graphene nanostructures (3DMGS) via catalytic graphitization and chemical oxidation-thermal reduction using biomass-based activated carbon (AC) as a precursor. The combination of microwave catalytic graphitization and chemical oxidation results in an active material with a unique physical and chemical structure. 3DMGS possesses a high specific surface area (503 m2 g−1) and an interconnected hierarchical porous structure with many defects and edges, which provide sufficient lithium-ion diffusion sites and facilitate fast ion transportation. When used as anode material for Li-ion batteries, 3DMGS exhibit outstanding rate capability and cycling stability (260 mAhg−1 at 5000 mAg−1 after 1100 cycles with charge retention of 114.47%.) and ultrahigh specific capacity (1513 mAhg−1 at 100 mAg−1).

The development of lignite-char-supported metal oxide catalyst for reduction of nitric oxide (NO) is investigated in this paper. The characteristics of NO reduction by copper and iron oxide catalysts supported on activated lignite chars (ALC) was studied using a fixed-bed reactor at 300 °C. The results showed that the impregnation of Cu on ALC resulted in higher catalytic reactivity during NO reduction compared with that of Fe. Chemisorption of O 2 and NO on Cu/ALC catalyst was found to play an important role in denitrification. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses showed that chemically adsorbed oxygen facilitates the formation of C(O) complex and oxidation of Cu 0 to Cu + for Cu/ALC catalyst. The C(O) intermediates and C* production formed due to the fact that C/O 2 reaction promoted the reduction of NO. It is suggested that the catalytic reaction of NO in this case comprised of C/O 2 reaction, C(O)/NO reaction and formation of N 2 and CO 2 . Cu seemed to have significantly promoted the C(O) formation and CO oxidation compared with Fe. The catalytic reactivity of Cu species for C(O) formation and CO oxidation followed the order of Cu 0 > Cu + > Cu 2 + . Fe 3 O 4 was believed to be the active phase in Fe catalyst. The oxygen and char-supported metal catalysts significantly promoted C/NO reaction, and therefore may lead to a lower operation temperature of NO x removal.

This paper presents a hybrid algorithm based on the invasive weed optimization (IWO) and particle swarm optimization (PSO), named IW-PSO. By incorporating the reproduction and spatial dispersal of IWO into the traditional PSO, exploration and exploitation of the PSO can be enhanced and well balanced to achieve better performance. In a set of 15 test function problem, computational results, preceded by analysis and selection of IW-PSO parameters, show that IW-PSO can improve the search performance. In the other comparative experiment with fixed iteration, the IW-PSO algorithm is compared with various more up-to-date improved PSO procedures appearing in the literature. Comparative results demonstrate that IW-PSO can generate quite competitive quality solution in stability, accuracy and efficiency. As evidenced by the overall assessment based on two kinds of computational experience, IW-PSO can effectively obtain higher quality solutions so as to avoid being trapped in local optimum.

The selective absorption of NO in flue gas has been investigated using a series of deep eutectic solvents (DESs) as novel denitrifying agents. The EG-TBAB DESs used in this work are composed of a hydrogen donor ethylene glycol (EG) and a parent salt tetrabutylammonium bromide (TBAB). Effects of DES composition (EG:TBAB molar ratio), operation temperature, residence time, and O

The paper reports the synthesis of SiC nanowhiskers via a process that utilizes carbon and silica from the same renewable source without the addition of external Si precursors as a sustainable and cost-effective method. This study reports an improved and sustainable method of synthesizing silicon carbide (SiC) nanowhiskers using cornstalk cellulose char under microwave heating. The aim was to optimize the process and gain a deeper understanding of the formation and growth mechanism of SiC nanowhiskers from biomass under microwave treatment in a temperature range of 1200–1400 °C. The synthesized product was then characterized by various analytical techniques. The formation of SiC nanowhiskers (β-SiC) was promoted at higher reaction temperatures, increasing from 6.83 wt% at 1200 °C to 9.35 wt% at 1400 °C. The SiC nanowhiskers displayed straight rod and smooth cylindrical structures. The nanostructure of β-SiC was confirmed along the d-spacing (111) plane, with a characteristic lattice fringe spacing of 0.25 nm. The growth mechanism of the SiC nanowhiskers followed two reaction pathways of vapor-solid (VS) and the vapor-liquid-solid (VLS). Increased CO and CO2 concentrations due to the evolution of gaseous products (SiO and CO) from the reactive cellulose char led to the growth of SiC nanowhiskers under the solid-vapor mechanism. The presence of inherent metallic species, such as Fe in biochar was found to catalyze the formation and growth of SiC nanowhiskers.

Biomass is a renewable hydrocarbon resource utilized to generate bioenergy, green chemicals, and carbon materials. Biomass is also promising source material for advanced carbon materials. This review reports the latest advancements and research activities in the synthesis of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) via microwave-assisted pyrolysis, covering various aspects of the formation mechanism and application. The large-scale poly-generation of carbon nanomaterials, high-value fine chemicals, and fuel gases via microwave pyrolysis can be promoted using selected biomass feedstock and by controlling reaction parameters. Cellulose is reported as the active bio-component accountable for the generation of CNTs under microwave. Although a self-extrusion mechanism has been proposed and elucidated in the literature, a recent study showed that the yield of CNTs has a linear correlation with the monosaccharides generated during biomass thermal decomposition. Selective heating and generation of hotspots were reported to promote the extrusion of volatiles. When combined with the temperature gradient of biomass particles, specific to microwave heating, and the presence of inherent inorganic species in biomass, microwave irradiation promoted the formation and growth of CNTs. Based on this technical review, the knowledge gaps and the possible future direction for generating carbon nanotubes from lignocellulosic biomass were identified.

The sulfidation and regeneration properties of lignite char-supported iron-based sorbent for coke oven gas (COG) desulfurization prepared by mechanical stirring (MS), ultrasonic assisted impregnation (UAI), and high pressure impregnation (HPI) were investigated in a fixed-bed reactor. During desulfurization, the effects of process parameters on sulfidation properties were studied systematically. The physical and chemical properties of the sorbents were analyzed by X-ray diffraction (XRD), scanning electron microscope coupled with energy dispersive spectroscopy (SEM-EDS), Fourier transform infrared (FTIR) and BET surface area analysis. The results of desulfurization experiments showed that high pressure impregnation (HPI) enhanced the sulfidation properties of the sorbents at the breakthrough time for char-supported iron sorbents. HPI method also increased the surface area and pore volume of sorbents. Sulfur capacity of sorbents was enhanced with increasing sulfidation temperatures and reached its maximum value at 400 °C. It was observed that the presence of steam in coke oven gas can inhibit the desulfurization performance of sorbent. SO2 regeneration of sorbent resulted in formation of elemental sulfur. HPIF10 sorbent showed good stability during sulfide-regeneration cycles without changing its performance significantly.

In this paper, iron oxide catalysts supported on corncob and lignite chars are used for catalytic reduction of NO in flue gas. Denitrification experiments were carried out in a fixed-bed reactor at temperatures of 100, 150, 200 and 300 °C by using simulated flue gas containing NO. Catalyst samples before and after denitrification were analyzed using Brunauer–Emmett–Teller (BET) analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope with an energy dispersive X-ray auxiliary (SEM–EDX). Results show that biomass–lignite chars impregnated with iron oxide had a high reactivity during catalytic reduction of NO. The denitrification efficiency of biomass–lignite chars impregnated with iron oxide catalyst was higher than that of un-impregnated char. The highest catalytic performance was achieved at corncob to lignite ratio of 5:5. Synergetic effects between lignite and biomass during co-gasification were attributed to the potassium migration from biomass to lignite char which improved the efficiency of NO removal. The catalysts had the highest denitrification efficiency at 300 °C and the reactions mechanism has been discussed.

In this paper, the regeneration characteristics of activated-char-supported Fe–Zn–Cu sorbents were studied. The desulfurization and regeneration experiments were carried out using a quartz fixed-bed reactor at ambient pressure. The effects of regeneration conditions, such as space velocity, temperature, and steam concentration, on the regeneration performance were examined. The crystal phase, chemical structure of activated components, and physical structure of sorbents before and after regeneration were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) surface area. The experimental results indicated that the char-supported Fe–Zn–Cu sorbents can be regenerated at temperatures above 500 °C. The optimal regeneration parameters with a space velocity of 5000 h–1, temperature of 700 °C, and steam concentration of 50 vol % have been obtained. The result of regener...

Lignite char supported Fe-Zn sorbents were prepared by means of impregnation of Fe and Zn into coal followed by steam gasification. The sulfidation experiments were carried out using a fixed-bed quartz reactor in the temperature range of 473 to 673 K using simulated coke oven gas with a gas space velocity of 1,000 h–1. Strcuture changes of sorbents during sulfidation were analyzed using X-ray diffraction and scanning electron microscopy. The results show that the sorbents can remove both H2S and coke oven gas from the simulated coke oven gas with high efficiency, and the desulfurization efficiency increased with increasing metal loading level.

Sulfidation properties of char-supported Fe-Zn-Mo sorbents prepared by ultrasonic impregnation method were investigated during simultaneous removal of H2S and COS from coke oven gas (COG) using a fixed-bed quartz reactor. Sorbent samples before and after sulfidation were analyzed using X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The experimental results showed that the addition of Mo significantly improved the desulfurization properties (i.e., breakthrough time, sulfur capacity and desulfurization efficiency) of Fe-Zn sorbents. Desulfurization reactions were exothermic and thermodynamically favorable in the temperature range of 200–400 °C. Thermodynamic analysis of the sorbents indicated that higher concentration of H2S and lower concentration of H2 favors the reaction of metal oxides with H2S to form metal sulfides.

Lignite char supported Fe–Zn–Cu sorbents were prepared by ultrasonic-assisted impregnation method for the simultaneous removal of H2S and COS from coke oven gas (COG). Sulfidation experiments were carried out in a fixed-bed quartz reactor using simulated COG. The results showed that the addition of Cu can significantly increase the sulfidation reactivity of char-supported Fe–Zn sorbents. Char-supported Fe–Zn–Cu sorbents with Fe:Zn:Cu molar ratio of 2:1:0.5 could simultaneously remove H2S and COS in the temperature range of 200–400°C. The sulfur capacity reached to 17.62 g S per 100 g sorbent at 400°C. The X-ray diffraction (XRD) analysis suggested that the addition of Cu into the Fe–Zn sorbent leads to the formation of composite oxides. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 352–358, 2016

The desulfurization properties of Fe–Zn sorbent prepared by impregnating Fe and Zn into lignite char via ultrasonic-assisted impregnation (UAI) were investigated in comparison with the mechanical stirring (MS) method. The sulfidation experiments were carried out using a fixed-bed quartz reactor under ambient pressure. The amounts of metals loaded into char were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). The crystalline phases and chemical structure of sorbents before and after sulfidation were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), respectively. The morphology of sorbents was analyzed by using scanning electron microscope (SEM) with an energy dispersive X-ray (EDX) auxiliary. The experimental results showed that metal oxides as the active components were evenly dispersed on char as nanoparticles. The impregnation of active components was significantly improved by the ultrasonic-assisted impregnation method. When sorbents were prepared by ultrasonic-assisted impregnation, the metal oxide particles became smaller and more evenly dispersed on the char matrix which resulted in higher desulfurization efficiency and sulfur uptake capacity of the sorbents. The BET results showed that the physical properties of sorbents (surface area and pore volume) significantly improved when prepared by UAI method compared to MS method. The sulfidation temperature had a significant effect on desulfurization performance of char supported sorbents. The Fe:Zn molar ratio of 2:1, and impregnation time of 9 h were suggested as the optimal preparation conditions during ultrasonic-assisted impregnation.

Coke oven gas cleaning is an important issue in China, where it can be a source of liquefied natural gas (LNG) through the methanation process. In this study, char-supported sorbents were prepared by loading iron, cerium, and molybdenum into a Chinese lignite through co-precipitation, and the sorbents were used for dry desulfurization of coke oven gases. Desulfurization efficiency of the sorbents was examined using a fixed-bed reactor in a temperature range of 473–673 K using a simulated coke oven gas. A gas chromatograph equipped with both a flame photometric detector (FPD) and a thermal conductivity detector (TCD) was used to analyze gas composition, while X-ray diffraction and scanning electron microscopy were used to examine chemical phases and the dispersion pattern of the active constitutes of the sorbents. The experimental results showed that the highest desulfurization efficiency and sulfur capacity appeared at 673 K. The reactivity of the nanosized active components in the char increased with inc...

The desulfurization behavior of novel Fe and Fe–Mo sorbents supported using Chinese lignite chars for desulfurization of hot coal gases was investigated and compared. The desulfurization experiments were carried out using a fixed-bed quartz reactor over a temperature range of 673 K to 873 K in simulated coal gas containing 0.47% H 2 S and 0.047% COS. The product gases composition and chemical phases of sorbents were analyzed using a gas chromatograph and X-ray diffractometer, respectively. The results show that iron and Fe–Mo sorbents supported on lignite char demonstrated high desulfurization efficiency under the present experimental conditions. The sulfur capacity of iron-based sorbents is determined by the amount of iron contained in the sorbents and the addition of Mo into the iron-based sorbents effectively improves the desulfurization efficiency of char-supported iron sorbents.

Oxy-fuel combustion of solid fuels is seen as one of the key technologies for carbon capture to reduce greenhouse gas emissions. The combustion characteristics of lignite coal, Chlorella vulgaris microalgae, and their blends under O2/N2 and O2/CO2 conditions were studied using a Thermogravimetric Analyzer-Mass Spectroscopy (TG-MS). During co-combustion of blends, three distinct peaks were observed and were attributed to C. vulgaris volatiles combustion, combustion of lignite, and combustion of microalgae char. Activation energy during combustion was calculated using iso-conventional method. Increasing the microalgae content in the blend resulted in an increase in activation energy for the blends combustion. The emissions of S- and N-species during blend fuel combustion were also investigated. The addition of microalgae to lignite during air combustion resulted in lower CO2, CO, and NO2 yields but enhanced NO, COS, and SO2 formation. During oxy-fuel co-combustion, the addition of microalgae to lignite enhanced the formation of gaseous species.