Combustion Characteristic Parameters Research Articles

Influence of mudstone on coal spontaneous combustion characteristics and oxidation kinetics analysis

To explore the spontaneous combustion characteristics and hazards of the low-temperature oxidation (LTO) stage in the process of spontaneous combustion of coal and mudstone, the pore structure, spontaneous combustion characteristic parameters, and exothermic characteristics of coal and mudstone were tested and studied, and the oxidation kinetic parameters were calculated. The results show that mudstone has a larger specific surface area and pore volume than coal. From the fractal characteristics, the pore structure of mudstone is more complex than that of coal. According to the comparison of theoretical and actual gas generation and oxygen consumption rate curves, it is found that there is an interaction between coal and mudstone in the LTO process. With the increase of mudstone mass ratio, gas production, and its oxygen consumption rate increase. Among them, CM-4 (Coal:Mudstone = 1:1) has the highest exothermic intensity and the exothermic factor (A) and fire coefficient (K) increase with the increase of mudstone content. The apparent activation energy of the mudstone sample is lower than that of the raw coal, indicating that the sample after adding mudstone is more likely to have spontaneous combustion in the LTO stage.

Characterization and kinetic analysis of lignocellulosic and algal biochar combustion

The combustion characteristics of biochar obtained from barley straw (BS) and brown algae (BA) are explored. Four different heating rates are utilized to determine the respective activation energies. A master plot analysis is used to identify the appropriate reaction model. The results show that the activation energies vary in the ranges of 6.86–48.36 and 46.34–77.51 kJ mol−1 for BS and BA biochar combustion, respectively. As the heating rate increases, most of the combustion characteristic parameters increase, while the combustion stability index decreases. These observations help provide a deeper understanding of the combustion of lignocellulosic and algal biomass-derived biochar.

Research on the Inhibitory Effect of Hydrated Phase Change Materials on Spontaneous Combustion in Coal

In order to study the effect of hydrated phase change materials on the suppression of spontaneous combustion in coal, a thermogravimetric experiment and a reaction activation energy analysis experiment were conducted to explore the changes in the combustion characteristic parameters, characteristic temperature, and activating energy of gas coal, long-flame coal, meagre coal, and lean coal before and after adding hydrated phase change materials. The research results indicated that hydrated phase change materials increased the characteristic temperature point of the coal samples and had effective inhibitory effects on different stages of the oxidation process. However, the effect was best at low temperatures, as hydrated phase change materials undergo phase change and absorb heat when heated at low temperatures, isolating coal from contact with oxygen. The activating energy increased by 1.138–23.048 KJ·mol−1 and the mass loss was reduced by 1.6%–9.3% after inhibition of the coal samples, indicating that the oxidation rate of the various coal samples was slowed down and, thus, spontaneous combustion can be suppressed through the use of hydrated phase change materials. At the same time, this material reduced the combustibility indices of meagre coal and lean coal, as well as the comprehensive combustion indices of long-flame coal and gas coal.

Near-Infrared Spectroscopy Modeling of Combustion Characteristics in Chip and Ground Biomass from Fast-Growing Trees and Agricultural Residue

This study focuses on the investigation and comparison of combustion characteristic parameters and combustion performance indices between fast-growing trees and agricultural residues as biomass sources. The investigation is conducted through direct combustion in an air environment using a thermogravimetric analyzer (TGA). Additionally, partial least squares regression (PLSR)-based models were developed to assess combustion performance indices via near-infrared spectroscopy (NIRS), serving as a non-destructive alternative method. The results obtained through the TGA reveal that, specifically, fast-growing trees display higher average ignition temperature (227 °C) and burnout temperature (521 °C) in comparison to agricultural residues, which exhibit the values of 218 °C and 515 °C, respectively. Therefore, fast-growing trees are comparatively difficult to ignite, but sustain combustion over extended periods, yielding higher temperatures. However, despite fast-growing trees having a high ignition index (Di) and burnout index (Df), the comprehensive combustion performance (Si) and flammability index (Ci) of agricultural residue are higher, indicating the latter possess enhanced thermal and combustion reactivity, coupled with improved combustion stability. Five distinct PLSR-based models were developed using 115 biomass samples for both chip and ground forms, spanning the wavenumber range of 3595–12,489 cm−1. The optimal model was selected by evaluating the coefficients of determination in the prediction set (R2P), root mean square error of prediction (RMSEP), and RPD values. The results suggest that the proposed model for Df, obtained through GA-PLSR using the first derivative (D1), and Si, achieved through full-PLSR with MSC, both in ground biomass, is usable for most applications, including research. The model yielded, respectively, an R2P, RMSEP, and RPD, which are 0.8426, 0.4968 wt.% min⁻4, and 2.5; and 0.8808, 0.1566 wt.%2 min⁻2 °C⁻3, and 3.1. The remaining models (Di in chip and ground, Df, and Si in chip, and Ci in chip and ground biomass) are primarily applicable only for rough screening purposes. However, including more representative samples and exploring a more suitable machine learning algorithm are essential for updating the model to achieve a better nondestructive assessment of biomass combustion behavior.

"Three Zones" Division of Spontaneous Combustion in Goaf of Y-type Ventilation Fully Mechanized Mining Face

The goaf of coal mine is accompanied by residual coal, and the possibility of spontaneous combustion determines whether the mine can work safely. Therefore, the division of "three zones" of spontaneous combustion in goaf under different working conditions is of great significance. This paper takes the 3154 fully mechanized coal face of Longmen Xianan Coal Mine as the research background to explore the "three belts" distribution under the Y-type ventilation mode. Based on the laboratory measured coal related spontaneous combustion characteristic parameters, the division standard of "three zones" is determined. Combined with the daily monitoring of the temperature and gas collection devices deployed on the site and the numerical simulation of the wind speed in the goaf, the comprehensive division of "three zones" in the goaf is realized. The results show that the range of "three zones" divided by temperature is similar to the range of oxygen concentration. The average width of heat dissipation zone and oxidation zone in the transport lane is 34.7m and 48.8m respectively. The asphyxiation zone is located at an average distance of more than 83.4m from the working face; The average width of the heat dissipation zone of the return air lane is 30.6m, the average width of the oxidation zone is 42.7m, and the average distance from the working face is more than 73.3m. In the numerical simulation, the width of the heat dissipation zone of the transport roadway is 35.0m, the width of the oxidation zone is 50m, and the asphyxiation zone is more than 85m from the working face. The width of the heat dissipation zone of the return air lane is 30m, the width of the oxidation zone is 40m, and the asphyxiation zone is more than 75m from the working face. The simulation results are close to the measured range of "three zones" of spontaneous combustion, and the width of "three zones" of return air roadway with Y-type ventilation is obviously different from that of transport roadway.

Pyrolysis and combustion characteristics of typical sealing materials for exterior building windows

Seals play a crucial role in preventing flame penetration through building exterior windows. However, as urban renewal accelerates, the number of discarded seals is also gradually increasing, which is not in line with the concept of green, energy-saving sustainable development. To gain a better understanding of the pyrolysis and combustion characteristics of sealing strips and facilitate their effective resource utilization and conversion into value-added fuels, we employed thermogravimetry, cone calorimetry, and flue gas spreading test equipment. Typical sealing and filling materials used for external windows of buildings, including EPDM ordinary adhesive strips (EPDM-O), EPDM flame-retardant adhesive strips (EPDM-R), as well as 20-fold expanding graphite strips and 30-fold expanding graphite strips (EG-20 and EG-30), were investigated. Comprehensive evaluations of their pyrolysis behaviors, kinetic parameters, and combustion characteristic parameters were carried out. The results showed that EPDM exhibits good thermal stability, while EG had better demonstrates favorable pyrolysis properties and expansion densification. Average activation energies of EPDM-O and EPDM-R in the combustion phase were 68.35 kJmol−1 and 92.40 kJmol−1, respectively. Moreover, the average activation energies of EG-20 and EG-30 in the expanding combustion phase were 67.42 kJ·mol−1 and 68.62 kJ·mol−1, respectively. The reaction rate of combustion stage is faster than that of pyrolysis stage. Furthermore, For the combustion, the flame growth index (FGI) of EPDM is greater than that of EG, whereas the flame spread index (FPI) is lower than EG. When EPDM burns, the flame spreads rapidly, while EG expands and generates a large number of wormlike substances, effectively preventing the high temperature from spreading to the interior of the material. Analyses of smoke spreading tests have shown that both EPDM and EG can produce irritating flammable fumes at high temperatures, affecting the environment. These results provide a basis for the development of new materials and contributes to fire safety, smoke management, and personnel escape planning.

Study on the combustion characteristics and pollutant emissions of cold-pressed pellets and pellet powders in fluidized-bed

Wood pellets produced by cold-pressing reduces energy consumption, but also generates more pellet powders. In order to achieve the complete utilization of woody biomass, this study analyzed the combustion characteristic parameters, pollutant emissions, and combustion efficiency of wood pellets (WP) and pellet powders (PP–S, PP-L) in fluidized-bed. Thermogravimetric and fluidized-bed experimental results showed that: (1) PP-S presented the highest volatilization and burning rate, with the best combustion characteristic parameters. (2) Material size and excess air coefficient determined the fluidization pattern and temperature profile, the optimal excess air at the highest combustion temperature of PP-S, PP-L, WP was 1.25, 1.5, and 1.75, respectively. (3) The fly ash after combustion was mainly within the range of small (<32 μm) and large (>212 μm) sizes, with PP-S producing more fine ash and WP producing more coarse ash. (4) Increasing size from PP-S to WP and decreasing excess air coefficient both led to reduced emission of NO but increased emissions of CO and CxHy. (5) The combustion efficiency of PP-S was the highest and basically unaffected by excessive air coefficient. Increasing excessive air coefficient reduced the heat loss of PP-L and WP, and promoted their combustion efficiencies.

Experimental and numerical study on the effects of initial pressure and temperature on the explosion characteristics of LPG mixtures

As a safe new renewable energy, liquefied petroleum gas (LPG) has the advantages of less environmental pollution and higher calorific value. Therefore, it is of great significance for the sustainable development of Chinese new energy sources to study the fuel explosion characteristics of LPG. The maximum explosion pressure (Pmax), maximum rates of the pressure rise ((dp/dt)max), and explosive index (KG) of LPG were investigated experimentally and numerically at various initial pressures (0.1–0.2 MPa) and temperatures (25–100 °C). Through the analysis of the experiment results, it was found that: as the initial pressure increases, the Pmax and (dp/dt)max of the mixed gas gradually increase. The Pmax of the mixture decreases with the increase of initial temperature. A fitting relationship between the other relevant combustion and explosion characteristic parameters (KG), initial temperature, and initial pressure is obtained within the experimental range. Numerical simulation was carried out with the help of the Chemical Kinetics (CHEMKIN) software. From the simulation results, it was found that the changes in Pmax and (dp/dt)max of the mixture were consistent with the experimental results. Through the sensitivity analysis of the mixture, the elementary reaction which plays an important role in the reaction process of the mixture was obtained. This work is expected to be conducive to safety management and the prevention of explosion accidents.

Thermal Analysis Kinetics Study of Pulverized Coal Combustion under Oxygen-Rich Atmosphere.

The thermal analysis kinetic behavior of pulverized coal combustion in different oxygen-rich atmospheres is studied with a thermogravimetric (TG) analyzer. The effects of heating rate on combustion characteristic are considered. The results showed that the combustion rate of pulverized coal increased and the burnout time decreased under the conditions of an oxygen-enriched atmosphere and high heating rate. As the heating rate increases, the TG and derivative TG curves of the coal samples generally move toward the high-temperature region, and the thermal hysteresis phenomenon occurs. The changes in oxygen concentration and heating rate mainly affect the combustion stage of coal samples. The decrease in heating rate or the increase in oxygen concentration will cause a decrease in ignition point temperature and burnout temperature. Under the condition of 40% O2, the oxygen concentration and heating rate have the greatest influence on the combustion characteristic parameters. In addition, the combustion reaction of pulverized coal in the warming process was analyzed by FWO and KAS methods, respectively. The results showed that the changes in oxygen concentration and heating rate affected the activation energy, and the activation energy of coal samples increased with the increase in oxygen concentration.

Effects of water immersion and pre-oxidation on re-ignition characteristics of non-caking coal

Coal spontaneous combustion (CSC) in waterlogged goafs has become an essential threat to coal mine safety production, so it is necessary to comprehensively and deeply evaluate the re-ignition characteristics of residual coal after water immersion and pre-oxidation. The re-ignition process of non-caking coal under the influence of water immersion and pre-oxidation was tested using a temperature-programmed test system (TPTS), and the spontaneous combustion characteristic parameters and limit characteristic parameters of low-temperature oxidation were calculated. The results show that the spontaneous combustion characteristic parameters such as CO production rate, oxygen consumption rate, and heat release intensity positively correlate with temperature. The minimum float coal thickness and lower limit oxygen concentration show a trend of increasing and then decreasing with the temperature increase, while the maximal air leakage intensity is the opposite. In addition, the expansion of pores and cracks caused by water immersion and pre-oxidation processes and the increase of unstable functional groups promote the oxygen consumption and heat generation of immersed and oxidized coal, which reduces the characteristic temperature, and activation energy, and limit characteristic parameters. Meanwhile, water immersion and pre-oxidation can synergistically accelerate the low-temperature oxidation process of non-caking coal, which significantly increases the CSC risk of coal O140I30 and coal O90I30. The results enrich the research on the characteristics of water immersed and oxidation coals re-ignition, which may be applied to prevent CSC in the future.

Effect of Pilot Injection Strategy on Performance of Diesel Engine under Ethanol/F-T Diesel Dual-Fuel Combustion Mode

To reduce emissions and save energy, alternative fuel and dual-fuel mode have been widely applied in the field of diesel engines. The pilot injection has potential to reduce engine vibration noise and pollutant emissions. The effects of a diesel fuel pilot injection strategy on the performance of an ethanol/F-T diesel dual-fuel engine were experimentally investigated on a four-cylinder four-stroke common rail diesel engine modified with an ethanol injection system. The results indicate that the variation in the combustion characteristic parameters with pilot injection timing is nonlinear and the difference is small, while soot, NOx, and CO tend to decrease, with an increase in pilot injection timing. With the increase in pilot injection amount, pmax, combustion duration, CO and soot increased; pmax phase and CA50 were closer to TDC; HRRmax and the ignition delay period decreased. The BSFC tends to increase with the increase in pilot injection timing and the increase in pilot injection amount, while the BTE shows the opposite trend. The value and the variation range of COVpmax are small. The effect of the pilot injection amount on ethanol/F-T diesel dual-fuel engine is more significant. The research presented in this paper can provide reference directions for the formulation of a fuel injection strategy of ethanol/F-T diesel dual-fuel combustion mode to reduce NOx without worsening the combustion process and presenting an insufficient fuel economy.

Experimental Study on the Influence of Pore Structure and Group Evolution on Spontaneous Combustion Characteristics of Coal Samples of Different Sizes During Immersion.

To study the influence of water immersion on the evolution of the groups and spontaneous combustion characteristics of coal samples with different sizes, raw coal from the Fengshuigou Coal Mine operated by Pingzhuang Coal Company in Inner Mongolia was studied. The infrared structural parameters, combustion characteristic parameters, and oxidation reaction kinetics parameters of D1-D5 water immersion coal samples were tested, and the mechanism of spontaneous combustion during the oxidation of submerged crushed coal was investigated. The results were as follows. The water immersion process promoted the re-development of coal pore structure, and the micropore volume and average pore diameter were 1.87-2.58 and 1.02-1.13 times those of raw coal, respectively. The smaller the coal sample sizes, the more significant the change. At the same time, the water immersion process increased the contact point between the active group and oxygen in the coal, and the C=O, C-O, and -CH3/-CH2- groups in coal were further promoted to react with oxygen to generate -OH functional groups and improve the reactivity of coal. The characteristic temperature of water immersion coal was affected by the temperature rise rate, coal sample size, coal voidage, and other factors. Compared with the raw coal, the average activation energy of the water immersion coal with different sizes decreased by 12.4-19.7%, and the apparent activation energy of the coal sample with a size of 60-120 mesh was the lowest on the whole. In addition, the apparent activation energy in the low-temperature oxidation stage was significantly different.

Prediction of combustion promotion effect of high/low-frequency AC electric fields based on machine learning method

Electric field-assisted combustion has become a trend in the past several decades. The effects of low-frequency and high-frequency AC electric fields on the flame propagation and combustion process of CH4-N2-O2 lean burning flame are compared experimentally, and different machine learning methods are applied to predict the flame propagation and combustion characteristics in this research. The experimental results show that both the fields can affect the flame significantly in the electric field direction, while the flame front under a low-frequency field is more stable. The promotion effect of the fields on the average flame propagation speed is in the same order, and the high-frequency fields increase the combustion pressure and pressure rise rate more than the low-frequency one. Support vector machine and artificial neural network are used to establish the correlation model of the average flame propagation and combustion pressure, respectively. It is found that the generation ability and the prediction performance of the models are very impressive and reliable. The correlation coefficient of each model established by SVM method is over 0.998, and the values of MAPE and Theil IC are below 1.093% and 0.007, respectively. The calculation speed of the ANN model is much higher than that of the SVM one. Besides, the results of the SVM method are more deterministic than that of the ANN method. Present work illustrates that machine learning methods provide time-saving research approaches for the forecasting of the flame propagation and combustion characteristic parameters in the electric field-assisted combustion field.

Effect of removal of alkali and alkaline earth metals in cornstalk on slagging/fouling and co-combustion characteristics of cornstalk/coal blends for biomass applications

Co-combustion of cornstalk/coal blends is feasible for large-scale renewable energy commercialization. However, alkali and alkaline earth metals (AAEMs) in cornstalks can cause slagging/fouling problems. In this study, the ash micro-characteristics, slagging/fouling indexes, and combustion behavior of cornstalk, coal, cornstalk after pretreatment, and cornstalk/coal blends were investigated using scanning electron microscopy, X-ray diffraction, X-ray fluorescence, and thermogravimetric experiments. The results demonstrate that cornstalk ash is smoother than coal ash. There are few significant differences in the micromorphology and minerals between the coal and blends. Various chemicals were used to remove AAEMs, with the most to the least effective being (i) soaking in hydrochloric acid, (ii) soaking in ammonium acetate ≈ soaking in distilled water, and (iii) untreated. After soaking in hydrochloric acid, the mineral content containing potassium, calcium, and magnesium significantly decreased in cornstalk ash, except for sodium salt. All pretreatments can effectively lower the slagging/fouling indexes of cornstalk ash and blends. Pretreatment to remove AAEMs would restrain volatile release in cornstalk. The blend resists the volatile release of cornstalk but is helpful for the coke combustion of coal. AAEMs can lower some characteristic temperatures but do not increase the combustion rate and combustion characteristic parameters in the co-combustion of blends.

Numerical simulation study on suppression effect of water mist on PMMA combustion under external radiant heat flux

Numerical model was built with fire dynamic simulator and theocratical simulation was carried out to investigate the suppression effect of water mist on ignition and combustion process of typical solid material polymethyl methacrylate under external radiant heat flux. Characteristic parameters such as ignition time, surface temperature, heat release rate and temperature distribution of flame central plane during ignition and combustion process under different thermal radiant fluxes were obtained and compared with experimental results. The suppression effect of spray droplets on ignition and combustion process was analyzed and discussed. The results show the theoretical calculations of combustion characteristic parameters are in good agreement with experimental measurements. Water mist droplets can effectively delay the ignition time. Quantitative data proves that the water mist flow rate at 0.9 L/(min·m2) can delay the ignition time of samples by about 1,100 s while the radiant heat flux is 50 kW/m2. The simulation results can provide theoretical support and data reference for typical solid material fire prevention and fire extinguishment in practice.

Experimental study and prediction model of combustion stability and combustion mode variation of burning methanol/biodiesel blends for diesel engines

The combustion stability is an essential metric for evaluating the stable operation of an engine. To analyze the underlying reasons affecting the combustion stability, tests of modified engines fueled by methanol/biodiesel blends were carried out. The influence of the potential ignition point (PIP), activation energy (Ea) field, flame diffusion, and other combustion characteristic parameters on the combustion stability is quantitatively analyzed through the CFD simulation model. The results show that under 2400 r/min and 100% load, a 10% volume concentration of methanol increases the peak pressure. The variation of the pressure and combustion characteristic parameters increased with the increase in methanol concentration. The increase in methanol concentration increases the number of PIP, expands the distribution range of low Ea, and reduces the flame diffusion rate. The PIP, Ea field, and flame diffusion have an echelon progressive, positive correlation with the combustion mode. The increase in methanol concentration is sufficient to cause the conversion of the mixed fuel combustion mode, and the corresponding methanol volume concentration threshold is 21–22%.

Optimization of temperature parameters for the autothermic pyrolysis in-situ conversion process of oil shale

In this study, a temperature optimization strategy for the Huadian oil shale autothermal pyrolysis in-situ conversion process (ATS) was first proposed by systematically investigating the reaction characteristics of various semi-cokes. As the pyrolysis temperature rised, the semi-coke's calorific value was found to undergo three different stages of increasing, decreasing, and flattening, peaking at around 330 °C. Additionally, the semi-cokes formed at different temperatures exhibited similar combustion characteristics, including combustion activation energy, combustion characteristic parameters, and product release characteristics. Due to the serious pore blockage caused by the substantial generation and the ignition coking of the bitumen, the reaction characteristics of semi-cokes were dramatically decreased at about 330 °C. Finally, the relationship between in-situ heat generation and demand at various stages of ATS process was discussed, and a reasonable strategy for the screening of temperature parameters was proposed. According to this strategy, the optimal control temperature for the preheating stage was determined at 350–370 °C and at Tact (defined in 4.3.2) for the retorting zone in the reaction stage. The results of this study provide a new perspective on the theoretical foundation of the ATS process and have crucial guiding implications for practical engineering applications.

Experimental investigation on RP‐3 aviation kerosene large‐scale pool fires at high altitude

AbstractRP‐3 aviation kerosene is a standard fuel that is used in civil aircraft and is a substitute for Jet‐A fuel. This paper investigates the combustion behaviour of RP‐3 aviation kerosene in an open space in the low‐pressure environment of a plateau. A series of large‐scale pools with diameters ranging from 0.4 m to 2.82 m combustion experiments are performed. Typical combustion characteristic parameters, including combustion rate, flame height and axial plume temperature distribution is measured. Results show that a low‐pressure environment significantly affects pool fires. With combustion rate, there is a linear variation law between oil pool size and combustion rate. The experimental data are fitted as a means of obtaining the large‐scale combustion rate relationship equation at low pressure. Experimental flame height data is compared using classical prediction models. Prediction model coefficients at low pressure are determined. The axial plume temperature distribution is greater than in the literature findings due to flames becoming longer in a low‐pressure environment. The three regimes in McCaffery's model are redefined and correlate well with the vertical temperature profile of the pool centreline. The results of the experimental investigation will help research fire hazards in low‐pressure environments while also contributing to the provision of basic data for the development of firefighting operation strategies.

Black Carbon Emission Prediction of Diesel Engine Using Stacked Generalization

With the continuous growth of international maritime trade, black carbon (BC) emissions from ships have caused great harm to the natural environment and human health. Controlling the BC emissions from ships is of positive significance for Earth’s environmental governance. In order to accelerate the development process of ship BC emission control technologies, this paper proposes a BC emission prediction model based on stacked generalization (SG). The meta learner of the prediction model is Ridge Regression (RR), and the base learner combines four models: Extreme Gradient Boosting (XGB), Light Gradient Boosting Machine (LGB), Random Forest (RF), and Support Vector Regression (SVR). We used mutual information (MI) to measure the correlation between combustion characteristic parameters (CCPs) and BC emission concentration, and selected them as the features of the prediction model. The results show that the CCPs have a strong correlation with the BC emission concentration of the diesel engine under different working conditions, which can be used to describe the influence of the changes to the combustion process in the cylinder on the BC generation. The introduction of the stacked generalization method reconciles the inherent bias of various models. Compared with traditional models, the fusion model has achieved higher prediction accuracy on the same datasets. The research results of this paper can provide a reference for the research and development of ship black carbon emission control technologies and the formulation of relevant regulations.

Investigation on the co-combustion characteristics of multiple biomass and coal under O2/CO2 condition and the interaction between different biomass

The co-combustion of coal and biomass in O2/CO2 conditions is a promising technology for CO2 capture and waste disposal. Little attention has been paid to the interaction between different biomass in co-combustion process, which is of great significance to the study of the co-combustion mechanism. The co-combustion behavior of coal and multiple biomass under isothermal conditions was characterized by thermogravimetric method, and the interaction between different biomass was investigated from the perspective of thermogravimetric and proximate analysis. It found that biomass blending could remarkably improve the combustion performance of coal. Compared to the theoretical prediction, the interaction between coal and biomass showed remarkably promoting effects when the coal was blended with different biomass. While the interaction between different biomass was weak. Moreover, the influence of proximate analysis on combustion characteristic parameters was studied by establishing the linear relationship between combustion characteristic parameters and proximate analysis. The effects of proximate analysis on characteristic time/S were divided into five categories, and it were mainly controlled by the interaction both between coal with biomass and between different biomass.