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In this study, co-pyrolysis experiments were carried out by blending coal slime (CS) and traditional Chinese medicine residue (CMR) in different proportions under nitrogen atmosphere using thermogravimetry-Fourier infrared spectroscopy-mass spectrometry (TG-FTIR-MS). Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) were used to calculate the activation energy (E) of samples with different conversion rates (α). The PCA method was used to analyze and compare the contribution of samples with different blending ratios to the principal components, and draw its score and load graph. A variety of artificial neural network models composed of different network topologies are selected to simulate and predict the remaining mass of the CS and CMR mixture pyrolysis, and the optimum model is obtained. [ABSTRACT FROM AUTHOR]

This work focused on the evaluation of co-combustion of sewage sludge (SS) and rice husk (RH) using thermogravimetric–Fourier transform infrared spectrometry method (TG–FTIR). The thermal behavior was assessed through the combustion characteristic, interaction, kinetics, and gaseous product characteristics. The (co-)combustion process was divided into three stages. Index D exponentially increased as RH blending ratio increased and index S also increased from 10 to 70% RH blending ratio, indicating that the combustion behavior was improved by the RH blending. The activation energy was evaluated by two model-free iso-conversional methods: Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS). The minimum value of average activation energy among blends was obtained at sample with 30% RH blending, which was 103.31 kJ/mol by FWO and 97.81 kJ/mol by KAS. Several typical gaseous products and functional groups were detected by FTIR spectrum. The results showed that CO2 was the main volatile and its yield increased with the RH blending ratio. [ABSTRACT FROM AUTHOR]

Scrap tire is a typical waste fuel, for which the combustion in the form of pellets is a feasible way. In this work, the ignition behavior, combustion process and pollutant emission of the scrap tire in pellet form are explored. The experiments were performed in the vertical heating tube furnace under different coflow conditions in CO2/O2 atmosphere. The temperature was set to 873, 973, 1073 K and the gas flow rate was set to 5, 10 and 20 L/min. The combustion images of scrap tire were recorded by the high-performance camera. The scrap tire pellet presented the characteristics of homogeneous ignition and the fly ash was captured around the scrap tire pellets. Increasing oxygen concentration and temperature shortened the ignition delay time and reduced the internal ignition temperature. The splash flame occurred during the volatile combustion under the conditions of high temperature, high oxygen concentration, and high gas flow rate. The distinct pores and cracks were found on the surface of char during the char combustion. The yields of pollutant gas increased as the gas flow rate increased from 5 to 20 L/min. With the increase of temperature, the emission of NO and SO2 was increased but NO2 emission was decreased. [ABSTRACT FROM AUTHOR]

Summary: To solve the problems of energy shortage and waste accumulation, the method of co‐combustion of sewage sludge (SS) and peanut shells (PS) was proposed. SS‐PS co‐combustion characteristics in air were investigated using artificial neural networks (ANN) and thermogravimetric analyses (TGA). The proportion of PS in the mixture was 10%‐50%. The temperature range of PS combustion (160‐560°C) is lower than that of PS combustion (170‐600°C). Activation energy was estimated from two non‐isothermal kinetic analysis methods: Kissinger‐Akahira‐Sunose (KAS) and Flynn‐Wall‐Ozawa (FWO). The kinetic mechanism of the combustion process was determined by using the master‐plots method. Multiple ANN models were established to predict TG data of SS‐PS co‐combustion. The best prediction model (ANN21) was obtained. The results showed a good overlap between the predicted and experimental TG data. The ANN model and the master‐plots method are the main innovations of this study. This study can promote the utilization and reduction of solid waste, and give guidance for the large‐scale application of SS‐PS co‐combustion. [ABSTRACT FROM AUTHOR]

In this study, an experiment of macroscopic spray performance of stabilized nanofuels under high injection and ambient pressure is conducted on a Common rail direct fuel injection. The tested nanofuels have been prepared by DE20 (20% ethanol, 80% diesel by volume) blends with nano-CeO 2 at 25 ppm(DE20Ce25), 50 ppm(DE20Ce50),100 ppm(DE20Ce100) respectively. Furthermore, appropriate amount of CTAB whose weight is equal to CeO 2 and 2%vol 1-decanol were added as surfactant additive. All tested fuels were ultrasonically oscillated at a frequency of 40 khz for 45min in order to enhance their stability. The macroscopic spray characteristics of diesel-ethanol with dispersed cerium nanoparticles have been measured using the optical diagnostic techniques of shadowgraph. Comparing with those the pure diesel(D100), the spray penetration of DE20, DE20Ce25, DE20Ce50, DE20Ce100 increased by −3%, −1.8%, −0.3% and 9.5%, while the spray cone angle increased by −3%,4%,2.8% and 12.5% as well as spray area increased by −3%,-1.3%,0.6% and 31% respectively. The addition of nanoparticles also enhances the instability of fuel and shortens the crucial breakup time. In addition, the influence caused by increasing viscosity and surface tension are balanced by the disturbance. Furthermore, the macroscopic spray characteristics of DE20Ce50 show little difference with the pure diesel which means it can be a promising alternative fuel for CI engine with no required modification. • Investigating the macroscopic spray characteristics of CeO 2 -nanofuel. • The addition of nanoparticles can shorten the breakup time. • The increase of viscosity and surface tension can be balanced by disturbance. [ABSTRACT FROM AUTHOR]

The ignition and combustion characteristics of anthracite-rice husk (AC-RH) and bituminous coal-rice husk (BC-RH) pellets were investigated in a vertical heating tube furnace under different experimental condition, for gas temperature (873 K–1073 K) and under air and different oxygen concentration (21–70%) in CO 2 /O 2 atmosphere. The investigation of the ignition and combustion characteristics focused on ignition mechanism, ignition delay, ignition temperature and combustion process. AC-RH pellets had two ignition mechanism in CO2/O2 atmosphere: homogeneous ignition of volatile and heterogeneous ignition of char. Heterogeneous ignition region decreased while homogeneous ignition increased as rice husk blending ratio increased in oxygen concentration-gas temperature plane. Only homogeneous ignition was observed when rice husk blending ratio was 30%. As for BC-RH pellets, only homogeneous ignition occurred in all experimental conditions. The effect of the rice husk blending on the anthracite was more pronounced than the bituminous coal for ignition mechanism. As oxygen concentration increased, a significant reduction in ignition delay and ignition temperature was observed at low rice husk blending ratio and low gas temperature. but at 1073 K, high oxidizer temperature weakened the effect of biomass blending and oxygen concentration on ignition delay and ignition temperature. Meanwhile, at 20% and 30% rice husk blending ratio, it also weakened the effect of oxygen concentration and oxidizer temperature on ignition delay and ignition temperature. In contrast, blending ratio had a more significant effect on ignition behavior. The replacement of N 2 by CO 2 at the same oxygen concentration contributed to an increase in ignition delay time and internal ignition temperature, which suppressed the ignition behavior. Different ignition mechanisms corresponded to different combustion processes. • The ignition and combustion behavior of coal-biomass blend pellet was investigated. • The critical condition of the transition for ignition mechanism was found. • The effect of Tg, O2% and BRH on ignition delay and temperature was discussed. • The effect of RH blending on anthracite was pronounced than bituminous coal. [ABSTRACT FROM AUTHOR]

Summary: This study applied the artificial neural networks (ANNs) model to the thermal data obtained by suspension ignition and combustion experiment of single peanut shells (PS, millimeter scale) pellet under O2/CO2 atmosphere. ANN11 was the best ANN model for predicting the relevant parameters of PS combustion. The coincidence between ANN prediction data and experimental data was over 99%. Two modes of biomass pellet ignition were observed: homogeneous ignition of volatiles and hetero‐homogeneous ignition of volatiles and char simultaneously. The ignition mode was transformed from homogeneous ignition to hetero‐homogeneous ignition when oxygen concentration was 50%. In addition, it was observed that ignition at the bottom emerged first, and then the upper end was ignited, finally generating an envelope flame. This phenomenon occurred when gas flow temperature exceeded 873 K or the oxygen concentration was greater than 50%. The reduction of ignition delay time and internal ignition temperature from 21% to 50% oxygen concentration was more intense than that of 50% to 100% oxygen concentration. Increasing oxygen concentration or temperature resulted in a shorter, brighter, and more stable volatile flame of biomass pellets, which reduced volatile burnout time. Nevertheless, the impact of gas flow rate on biomass combustion was intricate and irregular. [ABSTRACT FROM AUTHOR]