Quartz Tube Reactor Research Articles

Statistical student’s t-test in carbon nanospheres synthesis from cis-1,4-polyisoprene

AbstractA student's t-test was applied in carbon nanospheres synthesis from cis-1,4-polyisoprene considering the green chemical principles. The synthesis was carried out by Chemical Vapor Deposition method with a quartz tube reactor using an AISI 304 steel bar as catalyst. It was possible to obtain two types of different samples, one from the surface of the steel bar (catalyst) and another from the quartz tube surface (without catalyst) in the same experiment. Carbon spheres were observed in both samples by micrographs obtained by FESEM. The Raman and FTIR spectroscopies shown characteristic bands of this carbon structures (G and D). The results obtained by student's t-test proved a statistical significance between spheres means of samples collected from steel bar and quartz tube surface.

Experimental kinetic studies on the effects of organic additives on ammonia-based selective non-catalytic reduction process.

The effect of organic components including ethanol, acetic acid, and benzene on ammonia-based selective non-catalytic reduction (SNCR) process has been investigated. Experiments were performed through a quartz tube reactor with simulated flue gas and conducted from 973 to 1373 K. The combustion and pyrolysis properties of organic components were carried out first, it was found that all the combustion processes were completed ahead of the pyrolysis, and the combustion and pyrolysis temperatures for benzene are the highest among the three organic components. Ethanol addition promoted the removal of NO in the temperature range of 973 to 1073 K, and the NO reaction temperature window was broadened, while NO removal was greatly inhibited under a higher temperature over 1100 K. With regard to the effect of addition of multiple organic components on NO removal, the combination of C2H6O and C2H4O2 significantly promoted this process, while the combination of C2H6O/C2H4O2 and C6H6 showed a negative effect on NO removal. The mechanism based on the radicals' reaction has been illustrated, showing the competition of these reactions under different situations.

Raman spectroscopic technique towards understanding the degradation of phenol by sodium persulfate in hot compressed water

Degradation of phenol by sodium persulfate (SPS) in hot compressed water (HCW) was investigated in a lab-built fused quartz tube reactor (FQTR) coupled with Raman spectroscopy system. The species of S2O82−, SO42−, HSO4−, SO32− and HSO3− in the reaction system were qualitatively and quantitatively analyzed by Raman spectroscopy. The hydrothermal stability of phenol and SPS at different temperature and the degradation of phenol by SPS were also studied. The results indicated that phenol was not stable in aqueous solution above 200 °C, and that only SO42− was generated in the hydrolysis of SPS at temperatures below 50 °C, and SO42− and HSO4− were generated at higher temperatures. The maximum conversion rate (90.93%) and mineralization efficiency (38.88%) of phenol by SPS was obtained at reaction temperature of 300 °C with 180 min reaction time. During the degradation of phenol by SPS, HSO4− was the main product and S∗ (not detected by Raman spectroscopy) exhibits a positive correlation with temperature. In addition, a degradation pathway of phenol by SPS was proposed. The degradation data for the kinetic analysis indicated that the reaction followed pseudo first-order kinetics, and the reaction rate constants (ks) were given as k50 °C = 0.0083 min−1, k100°C = 0.0197 min−1, k200 °C = 0.0498 min−1, k300 °C = 0.0619 min−1 and k400°C = 0.0505 min−1 at 30 min reaction. Moreover, the activation energy (12.580 kJ mol−1), the enthalpy change (9.064 kJ mol−1) and the entropy change (−222.104 J mol−1) of the reaction were also calculated.

Co-pyrolysis of eucalyptus and sodium polyacrylate: optimization and synergistic effect

Co-pyrolysis of eucalyptus and sodium polyacrylate was carried out in a quartz tube reactor and the process was optimized using response surface methodology (RSM). The statistical analysis revealed that both polymer/biomass ratio and temperature had the most significant effect on bio-oil yield (BY) and water content. The optimum condition for co-pyrolysis based on maximum BY and minimum water content was obtained at 550 °C (temperature), 0.54 (polymer/biomass ratio), 60 °C/min (heating rate), and 0.01 min (residence time). Co-pyrolysis at the optimum condition produced 0.36 kg of bio-oil from per kg of the blended feed stock (0.35 kg of sodium polyacrylate and 0.65 kg of eucalyptus). To understand the synergistic effect of co-pyrolysis, experimental values (EXV) were compared with theoretical values (THV). Co-pyrolysis showed negative synergistic effect on BY (EXV = 36.4 wt% and THV = 38.1 wt%) and water content (EXV = 20.8 wt% and THV = 24.7 wt%). However, positive synergistic effect was observed on HHV (EXV = 34.1 and THV = 30.1 MJ/kg) of bio-oil and yield of combustible gases (H2, CO, and CH4). SEM morphology revealed that co-pyrolysis had an appreciable effect on char obtained. FTIR analysis revealed high quality bio-oil from co-pyrolysis containing lesser oxygenated functional groups compared to bio-oil obtained from eucalyptus pyrolysis. GC–MS analysis indicated positive synergistic effect of co-pyrolysis on monoaromatic compounds, acids, and aldehydes while the negative synergistic impact on alcohol, furan, ester, and ketones.

Hydrothermal Liquefaction of Polycarbonate (PC) Plastics in Sub-/Supercritical Water and Reaction Pathway Exploration

Plastic pollution is one of the most important environmental issues being faced today. In this work, the hydrothermal liquefaction performance of polycarbonate (PC) in sub-/supercritical water was investigated using a quartz tube reactor. Response surface methodology (RSM) was employed to demonstrate the correlation between reaction conditions and liquefaction efficiency of PC. The conversion selectivity and product recovery efficiency of PC were also analyzed. Moreover, according to the experimental results, the liquefaction reaction pathways of PC were speculated. In addition, based on the established reaction pathways, the lumped parameter method was also used to calculate the liquefaction kinetics of PC. The results showed that phenol was the largest liquefied product of PC, followed by 4-isopropylphenol (IPrP) and 4-isopropenylphenol (IPP), and the recovery efficiency of these three components determined the level of liquefaction efficiency. The PC liquefaction favored a mild reaction temperature, long residence time, and low feedstock concentration. Finally, for identified products, a 57.70 wt % carbon liquefaction efficiency was obtained with a 5 wt % feedstock concentration at 400 °C for 60 min. The liquefaction pathways showed that in the initial stage of depolymerization, 4-tert-butylphenol was first formed as a structural regulator, and phenol and IPP were the primary liquefied products. The IPrP, 4-ethylphenol, and p-cresol were the secondary products. The kinetic results indicated that the liquefied intermediates were easily converted to form phenol and IPP, and the IPP and IPrP were not directly converted to phenol, but there was a clear conversion relationship between them.

Visualizing the importance of oxide-metal phase transitions in the production of synthesis gas over Ni catalysts

Abstract Synthesis gas, composed of H2 and CO, is an important fuel which serves as feedstock for industrially relevant processes, such as methanol or ammonia synthesis. The efficiency of these reactions depends on the H2: CO ratio, which can be controlled by a careful choice of reactants and catalyst surface chemistry. Here, using a combination of environmental scanning electron microscopy (ESEM) and online mass spectrometry, direct visualization of the surface chemistry of a Ni catalyst during the production of synthesis gas was achieved for the first time. The insertion of a homebuilt quartz tube reactor in the modified ESEM chamber was key to success of the setup. The nature of chemical dynamics was revealed in the form of reversible oxide-metal phase transitions and surface transformations which occurred on the performing catalyst. The oxide-metal phase transitions were found to control the production of synthesis gas in the temperature regime between 700 and 900 °C in an atmosphere relevant for dry reforming of methane (DRM, CO2: CH4 =0.75). This was confirmed using high resolution transmission electron microscopy imaging, electron energy loss spectroscopy, thermal analysis, and C18O2 labelled experiments. Our dedicated operando approach of simultaneously studying the surface processes of a catalyst and its activity allowed to uncover how phase transitions can steer catalytic reactions.

Biogas Reforming Conversion Character on Microwave-heating Carbon Receptor

Objectives:Methane (CH<sub>4</sub>) and carbon dioxide (CO<sub>2</sub>) are the main components of biogas and are produced from biomass gasification. These two gases are a by-product gases that can be used as an energy source and is known as a greenhouse gas that affects global warming. In order to convert the gas which is the main cause of global warming into high-quality fuel energy, the microwave reforming characteristic research was conducted. In this study, the reforming characteristics of microwave carbon receptor pyrolysis-gasification gas were investigated. In addition, reforming gas conversion characteristics according to the reforming temperature, flow rate, and CH<sub>4</sub> / CO<sub>2</sub> ratio, which are the main influence variables, were studied.Methods:Experiment was achieved in a microwave convertor which was installed a quartz tube reactor. The reactor was irritated by a microwave energy to heat carbon receptor in a sample basket which was placed at the center of the quartz tube. A simulated gas mixture of methane and carbon dioxide was fed into the carbon receptor in the reactor, and a reformed product gas was collected and analyzed using a GC-TCD.Results and Discussion:In the case of microwave reforming of a mixture gas of carbon dioxide and methane, hydrogen and carbon was produced by thermal decomposition of methane. The produced carbon was adsorbed to the receptor and interfered with the catalytic activity. The attached carbon was reacted with the carbon dioxide by gasification reaction to produce carbon monoxide, and was cleaned to maintain a constant reforming conversion.Conclusions:As a result, the conversion rate and the product gas yield were high when the receptor bad reforming temperature was high and the space velocity in the convertor was low. The increase in methane in the simulated gas resulted in low conversion due to carbon adsorption.

Syngas production by catalytic pyrolysis of rice straw over modified Ni-based catalyst

Ni-xLa/Al2O3-MgO-sawdust char catalysts were prepared by modifying the Ni/Al2O3 catalyst from two aspects of support and active components. The effect of Al2O3, MgO, sawdust char molar ratio, and La content of catalysts on syngas (H2 + CO) production in the catalytic pyrolysis of rice straw was investigated in a horizontal fixed-bed quartz tube reactor. Furthermore, the stability of catalysts with the optimum catalytic performance was tested and compared with that of the Ni/Al2O3 catalysts. X-ray diffraction, X-ray fluorescence, field emission scanning electron microscopy, energy disperse X-ray, and Brunauer-Emmett-Teller analyses were applied to understand the physiochemical properties of the supports and catalysts. The study revealed that the supports were composed of many irregular flaky particles and thus formed many pores. Moreover, the addition of La decreased the particle size of NiAl2O4 and increased the active metal surface of the Ni/Al2O3-MgO-sawdust catalysts. When the molar ratio of Al2O3, MgO, and sawdust char was 1:1:1 and the La content was 10 wt% (dry weight basis), the catalysts presented the highest syngas concentration of 78.9 vol% and the most stable performance during the catalytic pyrolysis process.

Catalytic performance and debromination of Fe–Ni bimetallic MCM-41 catalyst for the two-stage pyrolysis of waste computer casing plastic

A computer casing plastic waste containing brominated flame retardants (BFRs) was pyrolyzed in a two-stage vertical quartz tube reactor using iron and nickel metals modified MCM-41 catalysts. Various catalysts with different ratios of Fe and Ni were prepared and utilized to study their catalytic performance. At the presence of 20%Ni/MCM-41 catalyst, the pyrolytic yield of oil and gas reached maximum values of 49.9 wt% and 13.8 wt% respectively. The co-existence of Fe and Ni showed synergistic effect on oil composition by promoting the formation of valuable single ring hydrocarbons. With regard to the 15%Fe–5%Ni/MCM-41, 10%Fe–10%Ni/MCM-41 and 5%Fe–15%Ni/MCM-41 catalysts, the production of single ring hydrocarbons were 64.58%, 65.93% and 64.74% respectively. The bimetallic catalysts also exhibited remarkable effect on eliminating bromine from pyrolytic oil. At the presence of Fe–Ni/MCM-41, the bromine in pyrolytic oil was reduced to below 4 wt% compared with 10 wt% without catalyst. Higher amounts of Fe in the catalyst is beneficial for the debromination efficiency. The debromination process by the Fe–Ni/MCM-41 may be realized by these different mechanisms: catalytic cracking of organobromines, reaction of loaded metal oxides with HBr/SbBr3, and deposition of organobromines on the surface of catalyst.

Experimental investigation on gasification characteristics of polyethylene terephthalate (PET) microplastics in supercritical water

In this work, the gasification experiment of PET microplastics in supercritical water was carried out in a quartz tube reactor. The effect of operating conditions on gasification was investigated. Inspired by marine microplastics, the artificial seawater was provided to gasification. A detailed gasification model of PET microplastics was established to reveal the gasification path. The results showed that the increase in gasification temperature and time improved gasification efficiency, but the increase in reaction pressure had little effect on the characteristics of the supercritical water so that gasification efficiency did not change significantly. The carbon conversion of 98.00 wt% was obtained at 800 °C for 10 min. The metal salts contained in seawater promoted the gasification of plastics, which meant that seawater was an efficient utilization route to the plastic gasification. The gasification model demonstrated that PET plastics were prone to form biphenyl, which was not conducive to PET gasification at low temperatures.

Experimental study on gasification performance of polypropylene (PP) plastics in supercritical water

In this paper, the gasification performance of polypropylene (PP) plastics in supercritical water was investigated using a quartz tube reactor. A gasification model was demonstrated to reveal the gasification path. Different gasification models were compared to improve gasification efficiency. The response surface methodology (RSM) was employed to find the optimal gasification condition. Moreover, artificial seawater was used for gasification instead of ultrapure water. The results showed that the polypropylene plastic was a difficult gasification substance, the increase in temperature and time had a positive effect on the improvement of gasification, while increasing the feedstock concentration was not conducive to gasification. The optimal condition was 750 °C and 60 min, and the effect of temperature on gasification was more important than time. The gasification model believed that in the initial gasification stage, the easy aromatization of the fragments was key to generating tar. So a 10 wt% formic acid solution was employed to improve gasification, on which the 79.86 wt% of carbon conversion (CE) was obtained. Finally, seawater gasification results showed that seawater components had a positive impact on the gasification of PP plastics, which was an effective way to solve marine microplastics.

Preparation of fly ash nickel catalyst and its application in catalytic pyrolysis of rice straw for syngas production

The catalytic pyrolysis of rice straw for syngas (H2 + CO) production with nickel oxide (NiO)/fly ash catalysts was investigated in a horizontal fixed-bed quartz tube reactor. Besides, X-ray diffraction, X-ray fluorescence, field emission scanning electron microscopy, and Brunauer-Emmett-Teller analysis were employed to study the physiochemical properties of the catalysts before and after catalytic pyrolysis of biomass. The results illustrated that NiO was uniformly loaded on the surface of fly ash via a filament-like coating. Furthermore, the effects of calcination temperature (400 to 700 °C), reaction temperature (550 to 800 °C), holding time (5 to 35 min), and NiO loading (5 to 30 wt%) on the catalyst performance were investigated. Analysis of the gas composition showed that the NiO/fly ash catalyst had the best ability to increase H2 and CO concentration at a 400 °C calcination temperature, 600 °C reaction temperature, 20 wt% NiO loading, and 20 min holding time. Compared with rice straw pyrolysis alone at these conditions, the concentration of H2 and CO experienced a steep increase from 7 vol% to 41 vol% and 18 vol% to 34 vol%, respectively. The catalyst developed in this research opens a new pathway for the utilization of fly ash in the field of biomass pyrolysis.

Nickel Nanoparticle Catalyzed Growth of Multiwall CNTs on Copper thin Films Substrate

Significant applications of metallic nanocatalysts motivated us to study the role of catalyst contents by choosing Cu–Ni nanocatalyst in synthesizing carbon nanotubes (CNTs). Cu–Ni thin films were prepared by RF sputtering method with different deposition time of Ni. They inserted the prepared catalysts into a quartz tube reactor for carbon nanotubes fabrication. Scanning electron microscopy (SEM) recorded the diameter distribution of multi walled carbon nanotubes (MWCNTs) while atomic force microscopy (AFM) was applied for surface roughness estimation. Both analyses confirm the positive effect of deposition time on the catalytic properties of Cu/Ni nanocatalysts which ends to the improved quality of prepared CNTs. In addition, the structure of multi walled carbon nanotubes were investigated by Raman spectroscopy.

Catalytic supercritical water gasification of glucose with in-situ generated nickel nanoparticles for hydrogen production

Hydrogen production from catalytic supercritical water gasification of glucose with in-situ generated nickel nanoparticles in a quartz tube reactor is demonstrated. The effects of various operating parameters such as the presence of catalyst, resident time, reaction temperature and feed concentration on the gasification performances are studied. The results show that both the carbon gasification efficiency and the hydrogen gasification efficiency of glucose in supercritical water were improved with in-situ generated nickel nanoparticles as catalyst compared to those without catalyst. The catalyst promotes the water-gas shift reaction and CO methanation reaction, resulting in increased yields of H2, CH4 and CO2 and decreased yield of CO. At the presence of catalyst, 10 wt% glucose solution exhibits the best gasification performances at 500 °C. Highly dispersed nickel nanoparticles identified by high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) are assumed to be generated via supercritical hydrothermal synthesis through hydrolysis, dehydration and in-situ reduction. However, the in-situ generated nano-nickel catalyst underwent an activation to deactivation transition due to carbon deposition on the surface of nickel nanoparticles. Regeneration strategies of the deactivated catalysts need further study for practical application.

The effects of Sn infiltration on dry reforming of biogas at solid oxide fuel cell operating conditions over Ni-YSZ catalysts

This work presents successful infiltration of Ni-YSZ-based catalysts for dry reforming of biogas over a temperature range of 600−800°C. Ni catalysts over YSZ support are commonly used as solid oxide fuel cell (SOFC) anode material to catalyse the fuel, normally hydrogen, in electrochemical oxidation reaction to generate electricity. The objective of this work is to find suitable SOFC anode catalyst materials to enable the SOFCs to operate on biogas as a renewable and low cost fuel. There are challenges when biogas is used as fuel; biogas dry reforming is slow and deleterious carbon deposition is unavoidable. The slow electrochemical reaction leads to low SOFC performance. While accumulation of carbon deposits may reduce the catalytic activity, decrease the SOFC performance and can lead to a complete failure of the SOFC operation. In this work, tin salt was used as a dopant in careful infiltration of Ni-YSZ catalysts. Characterisations of the catalysts were performed using SEM, XRF and XPS. Dry reforming reactions were carried out in a quartz tube reactor attached to a quadrupole mass spectrometer to monitor the product gases. Various compositions of CO2:CH4 mixtures were used to simulate biogas. It was observed that at small quantities of less than 1 weight % Sn/Ni loadings, dry reforming of biogas produced much higher level of the desired CO and H2 gas products compared to that obtained over non-infiltrated NiYSZ catalyst. The developed Sn-Ni-YSZ catalysts were able to operate continuously for more than 48 hours without noticeable performance degradation. More work is still in progress; however, this work so far concludes that Sn-doped Ni-YSZ catalysts have improved dry reforming of biogas at SOFC operating temperatures and so promised successful operations of SOFCs using biogas, a renewable fuel source, to produce sustainable electricity with high efficiency.

Spray-Pyrolysis Preparation of Li4Ti5O12/Si Composites for Lithium-Ion Batteries

This paper introduces the novel anode material which is Li4Ti5O12/Si prepared by gas-stated method, mainly spray-pyrolysis technique. The literature review performed in this paper revealed two main components which can be potentially mixed into the efficient anode material. Silicon (Si) has the highest possible capacity of 4200 mAh g-1 among all commonly used anodes. Due to its ‘zero-strain’ (<1% volume change) properties and stable cycling, Li4Ti5O12 (LTO) is considered as a promising anode for lithium ion batteries. Combination of these two anode materials is considered as a promising approach to prepare a high performance composite anode. The precursor solution consisted of homogeneous mixture of lithium nitrate and titanium tetraisopropoxide dissolved in deionized water with equimolar concentration of 0.5 M. The aerosol formation was performed at nitrogen environment and the droplets were carried into the quartz tube reactor at the flowrate of 4 L min-1. The rector temperature was held at 800 °C. The spray-pyrolysis synthesis was performed as one-step operation, excluding the need of calcination of as-prepared powders, and continuous process by the mean of peristaltic pump. The as-prepared powders had wide size distribution from nanometers to microns. The materials obtained had well-crystallized structure with insignificant amount of impurities. The powders were analyzed by the following analytical equipment: 1) the presence of Li4Ti5O12 and Si in the obtained composite was confirmed by X-ray diffraction technique (XRD); 2) The structure and morphology of LTO and Si molecules were observed and studied with Scanning Electron Microscopy (SEM).

An experimental study on the gas and soot formation in ethanol pyrolysis

Ethanol is an alternative fuel to oil with high oxygen content, and its utilisation is helpful in solving the issues of petroleum shortage. Pyrolysis has always existed in the process of ethanol utilisation so it is very important to understand the process of gas production and soot formation during ethanol pyrolysis. Also, excessive soot will affect the effective use of ethanol, so the analysis of soot production at various conditions is significant, and soot rate is a key factor to predict and control soot yield. In the paper, pyrolysis experiments have been carried out in a quartz tube reactor in the temperature range of 700°C to 1,100°C, and a system combing a Fourier infrared spectrometer and a hydrogen analyser is used to detect the gas composition in the outlet of the reactor. By the oxidation using oxygen, the amount of soot deposited inside the reactor can also be measured. It is observed that temperature, ethanol concentrations and residence time can all affect the formation of gases and soot significantly. Also, the production of soot is obviously increasing during ethanol pyrolysis, especially for temperature over 1,025°C. By the carbon deposition rate under different items, an effective way to reduce soot have been obtained. Moreover, the impacts of the additions of methane, water vapour and oxygen on the formation of soot during ethanol pyrolysis have also been investigated. It is found that the amount of soot formed reduces as water vapour or oxygen is added, while the presence of methane exhibits a converse effect. [Received: December 12, 2015; Accepted: June 18, 2017]

Effects analysis on the gasification kinetic characteristics of food waste in supercritical water

The gasification kinetic characteristics of food waste (FW) gasification by supercritical water (SCW) were investigated by examining the SCW gasification (SCWG) of FW in a quartz tube reactor, and the experimental results were investigated by using a series of kinetic models. The experimental results show that the carbon gasification efficiency increases with reaction temperature at the same residence time, and reactivity increases sharply at the early stage of gasification and then decreases with reaction time. The simulation results show that all the classical kinetic models underestimate the experimental results, similar to the models used in previous work on coal gasification by SCW. The underestimation of the models results from the catalytic effect of alkaline earth metals (AAEMs), which can notably increase the active sites of gasification reaction without changing the gasification kinetic mechanism. To solve the above problem, the catalytical effect to describe the kinetic behavior of the SCWG of FW is considered and a semiempirical modified random pore model (MRPM) is developed based on the RPM model. The simulation results of the MRP models are close to experimental findings, indicating that MRP model can be used to predict the entire process of SCWG under different conditions without dividing gasification into different stages of reaction. The MRP model can also be used for the prediction of SCWG of coal, biomass, and organic wastes and is crucial to reactor optimization and scaling up.

Effect of Fe-Mo promoters on HZSM-5 zeolite catalyst for 1-hexene aromatization

The promotional effect of Fe-Mo species introduced into HZSM-5 (Zeolyst Int., SiO2/Al2O3 ≈ 30) zeolite catalyst by the wetness impregnation method for the 1-hexene aromatization was investigated. The structure and catalytic performance for the aromatization of 1-hexene over xFeyMo-ZSM-5 catalysts in comparison with unmodified HZSM-5 catalysts were studied. The xFeyMo-ZSM-5 catalysts contain fixed loading (5 wt%) and variable Fe/Mo ratio. The catalysts were characterized by BET, ICP-AES, HRSEM-EDS, HRTEM, XRD, FTIR, H2-TPR, NH3-TPD, and pyridine DRIFT spectroscopy. The characterization data confirmed the existence of Fe and Mo species in the zeolite matrix. With Fe and Mo species implementation to HZSM-5 zeolite, the amount of the acid sites decreased, but the selectivities to C9+ aromatics increased. The catalyst evaluation was performed at 350 °C for 6 h on-stream at atmospheric pressure using a fixed-bed quartz tube reactor. The selectivity to products of different carbon number was affected by the Fe/Mo ratio within the zeolite. It was found the product distribution of grouped fractions of C1–C17+ from the liquid product. The results indicate that the optimum ratio of Fe/Mo is 1–1.5. The highest selectivity for gasoline and distillate ranges was obtained for the 2.5wt%Fe2.5wt%Mo- and 3wt%Fe2wt%Mo-ZSM-5 samples, which was higher than that for parent HZSM-5 catalyst.

Experimental investigation on the conversion of fuel-N to NOx of quasi-particle in flue gas recirculation sintering process

Flue gas recirculation sintering process is a potential technology to decrease fuel consumption and NOx emissions compared with conventional sintering process. In present work, a vertical quartz tube reactor was used to investigate the combustion characteristics and conversion of fuel-N to NOx of quasi-particle. The mass conversion rate of quasi-particle increases with higher temperature. It was found that D1 model is more appropriate than other models to describe quasi-particle combustion process through comparing correlation coefficients calculated by different mechanism models. Effects of temperature, coke size and proportion, circulating flue gas components on the conversion of fuel-N to NOx of quasi-particle were studied. The conversion rate of fuel-N to NOx of quasi-particle increases with higher temperature. With increasing coke size and proportion, the conversion rate of fuel-N to NOx decreases obviously. O2 has a positive impact on the conversion of fuel-N to NOx of quasi-particle. CO could decrease the conversion rate of fuel-N to NOx by reducing NO directly or reacting with char to decrease NOx indirectly. CO2 has an obviously inhibitory effect on the conversion of fuel-N to NOx of quasi-particle because it reacts with char to generate CO. The results were conducive to further understanding the combustion behavior and NOx formation mechanism of quasi-particle during flue gas recirculation sintering.