Impacts of char structure evolution and inherent alkali and alkaline earth metallic species catalysis on reactivity during the coal char gasification with CO2/H2O

In this work, we studied the effects of char structural evolution and alkali and alkaline earth metallic species (AAEMs) catalysis on the reactivity during the char gasification with CO₂, H₂O, and their mixture. The gasified chars with different carbon conversion levels were prepared, and their physicochemical structures were characterized via nitrogen adsorption and FT‐Raman techniques. The concentrations of AAEMs in different modes were obtained by the sequential chemical extraction method. The reactivities of the raw and gasified chars were analyzed by the thermogravimetric analysis. The gasification atmospheres had varied effects on the physicochemical structure of coal char. The gasified char obtained in the CO₂ atmosphere had a lower aromatic condensation degree compared with that obtained in the H₂O atmosphere, irrespective of the temperature. The impact of the atmospheres on the specific surface area of the char varied with the temperature because H₂O and CO₂ have different routes of development of pore structure with coal char. A large specific surface area facilitates the exposure and dispersion of more AAEMs on the surface of the channel, which is conducive to their contact with the gasification agent to play the catalytic role. Thus, the reactivity of the gasified char is well correlated with its specific surface area at different gasification temperatures. In the absence of AAEMs, the chemical structure of coal char becomes the dominant factor affecting the reactivity.     

Gasification of preheated coal: Experiment and thermodynamic equilibrium calculation

A new process integrating a circulating fluidized bed (CFB) reactor and an entrained bed reactor was proposed for gasification of preheated coal. The CFB reactor as a preheater was successfully used in clean coal combustion. In this study, gasification of preheated coal was tested in a bench-scale test rig, which consisted of a CFB preheater and a down flow bed (DFB) gasifier. The effects of operating parameters of the preheater and gasifier were revealed via thermodynamic equilibrium calculations. A stable preheating process was obtained in the CFB preheater at the O₂/C molar ratio of 0.31 and higher gasification reactivity was gained in preheated char owing to the improvement in intrinsic reactivity, specific surface area and total pore volume. Effective gasification of preheated char was achieved in the DFB gasifier at 1100 °C and the total O₂/C molar ratio of 0.67, meanwhile the CO + H₂ yield and carbon conversion increased. Thermodynamic equilibrium calculations revealed when the gasification reaction rates varied little above 1100 °C and the same carbon conversion was achieve in gasifier, lowering the temperature would lead to an increase in cold gas efficiency and a decrease in O₂ demand.     

Experimental simulate on hydrogen production of different coals in underground coal gasification

Research on hydrogen production from coal gasification is mainly focused on the formation of CO and H₂ from coal and water vapor in high-temperature environments. However, in the process of underground coal gasification, the water gas shift reaction of low-temperature steam will absorb a lot of heat, which makes it difficult to maintain the combustion of coal seams in the process of underground coal gasification. In order to obtain high-quality hydrogen, a pure oxygen-steam gasification process is used to improve the gasification efficiency. And as the gasification surface continues to recede, the drying, pyrolysis, gasification and combustion reactions of underground coal seams gradually occur. Direct coal gasification can't truly reflect the process of underground coal gasification. In order to simulate the hydrogen production laws of different coal types in the underground gasification process realistically, a two-step gasification process (pyrolysis of coal followed by gasification of the char) was proposed to process coal to produce hydrogen-rich gas. First, the effects of temperature and coal rank on product distribution were studied in the pyrolysis process. Then, the coal char at the final pyrolysis temperature of 900 °C was gasified with pure oxygen-steam. The results showed that, the hydrogen production of the three coal chars increased with the increase of temperature during the pyrolysis process, the hydrogen release from Inner Mongolia lignite and Xinjiang long flame coal have the same trend, and the bimodality is obvious. The hydrogen release in the first stage mainly comes from the dehydrogenation of the fat side chain, and the hydrogen release in the second stage mainly comes from the polycondensation reaction in the later stage of pyrolysis, and the pyrolysis process of coal contributes 15.81%–43.33% of hydrogen, as the coal rank increases, the hydrogen production rate gradually decreases. In the gasification process, the release of hydrogen mainly comes from the water gas shift reaction, the hydrogen output is mainly affected by the quality and carbon content of coal char. With the increase of coal rank, the hydrogen output gradually increases, mainly due to the increasing of coal coke yield and carbon content, The gasification process of coal char contributes 56.67–84.19% of hydrogen, in contrast, coal char gasification provides more hydrogen. The total effective gas output of the three coal chars is 0.53–0.81 m³/kg, the hydrogen output is 0.3–0.43 m³/kg, and the percentage of hydrogen is 53.08–56.60%. This study shows that two-step gasification under the condition of pure oxygen-steam gasification agent is an efficient energy process for hydrogen production from underground coal gasification.     

Formation of the structure of chars during devolatilization of pulverized coal and its thermoproperties: A review

The paper provides an overview of current studies on the behaviour of coal during devolatilization, especially the experimental studies and modelling efforts on the formation of char structure of bituminous coals in the open literature. Coal is the most abundant fossil fuel in the world. It dominates the energy supply in the future and plays an increasing role particularly in the developing countries. Coal utilization processes such as combustion or gasification generally involve several steps: i.e., the devolatilization of organic materials, homogeneous reactions of volatile matter with the reactant gases and heterogeneous reactions of chars with the reactant gases. The devolatilization process exerts its influence throughout the life of the solid particles from the injection to the burnout, therefore is the most important step which needs to be understood. When volatile matter is generated, the physical structure of a char changes significantly during the devolatilization, some accompanying a particle's swelling. The complexity of a char's structure lies in the facts that the structure of a char itself is highly heterogenous inside an individual particle and between different particles and the chemistry of a char is strongly dependent on the raw coal properties. A char's structure is strongly dependent on the heating conditions such as temperature, heating rate and pressure. Understanding the swelling of coal and the formation of char's pore structure during the devolatilization of pulverized coal is essential to the development of advanced coal utilization technologies. During combustion and gasification of pulverized coal, the behaviour of individual particles differs markedly due to the variation of their maceral composition. Particles with different maceral constituents generate different types of char structure. The structure of a char has a significant impact on its subsequent heterogeneous reactions and ash formation. The review also covers the most recent studies carried out by the authors, including the experimental observations of the thermoplastic behaviour of individual coal particles from the density fractions using a single-particle reactor, the experimental analysis on chars prepared in a drop tube furnace using the density-separated coal samples, the development of a mathematical model for the formation of char's pore structure based on a simplified multi-bubble mechanism and the investigation on the effect of pressure on char formation in a pressurized entrained-flow reactor.     

Nitric oxide emissions during the evolution of gasified char in the reduction layer during a grate-fired process

This work examined the effects of CO₂ gasification in the reduction layer on NO emissions during subsequent char combustion in the oxidation layer during a grate-fired process. In experimental trials, the pyrolysis char of Shenhua bituminous coal was initially gasified in CO₂, employing different conversion rates so as to vary the residence time of the char in the reduction layer. The pore structure and degree of graphitization of the char were monitored and the effects of CO₂ gasification on NO emissions were ascertained. In this manner, the relationship between the transformation of char nitrogen and the physicochemical characteristics of the char was clarified. The effects of CO₂ gasification on the properties of the char and NO emissions in the subsequent oxidation layer were determined. The results show that CO₂ gasification can improve the pore structure and degree of graphitization of the char, such that NO emissions are reduced in an inert atmosphere. However, the conversion rate of char nitrogen will increase in conjunction with oxidative combustion.     

Regulation of chemical properties of ash and kinetic model construction of Lu’an coal gasification

The objective of this study was to enhance the suitability of Lu’an coal for gasification in large entrained-flow gasifiers currently used by the Lu’an Group Mining Company in its 1.8 million ton per annum coal-based oil synthesis demonstration project. The effect of coal blending and flux addition on the ash fusion temperature (AFT) and gasification reactivity was investigated. CaO, Fe₂O₃, and MgO decreased the AFT of Lu’an coal by 150°C, 73°C, and 68°C, respectively, by a flux addition of up to 7%. Within the range of the experimental investigation, the AFT of Lu’an coal decreased by 3°C for each 1% of Shenmu coal addition. The gradual reduction of mullite and the formation of fayalite and hessonite in blended coal ash decreased the AFT. The addition of a fluxing agent significantly increased the reaction activity of the char, with Fe₂O₃ exhibiting the largest catalytic effect on char gasification. Blending with Shenmu char significantly increased the gasification reactivity. The random pore model best describes the gasification process of Lu’an char, and a kinetic equation for the process was developed on the basis of this model.     

Study of the crystal structure effect and mechanism during chemical looping gasification of coal

Chemical looping gasification (CLG) of coal, in which oxygen is provided to coal by oxygen carriers directly, is a clean and efficient way to generate syngas. Thermo-gravimetric analysis (TGA) of lignite char with oxygen carriers was conducted in this work, and the experimental results indicated that the oxygen carriers, Ti_0·5Mn_0·5Fe₂O₄, MnFe₂O₄, FeTiO₃ and Fe₂TiO₄, had a positive effect on CLG of lignite char. The effect of these oxygen carriers was discussed in the perspective of the crystal structure. XPS experiment was performed and the spectra of O 1s revealed the effect of different element on reactivity of spinel-based oxygen carriers. Five kinetic models, including Uniform Reaction (UR), Integrated Model (IM), Modified Random Pore Model (MRPM), Random Pore Model (RPM) and Modified Volumetric Model (MVM), were employed for revealing the reaction mechanism. MRPM had the highest correlation coefficient for each oxygen carrier, which means the introduction of the oxygen carriers effectively increases the active site of the reaction surface.     

Distribution of Nitrogen Species During Vitrinite Pyrolysis and Gasification

The formation of HCN and NH₃ during pyrolysis in Ar and gasification in CO₂ and steam/Ar was investigated. Vitrinites were separated and purified from different rank coal from lignite to anthracite. Pyrolysis and gasification were carried out in the drop-tube/fixed-bed reactor at temperatures of 600–900°C. Results showed that with increase of reaction temperature the yield of HCN increased significantly during pyrolysis and gasification. Decrease of coal rank also increased the yield of HCN. Vitrinite from lower rank of coal with high volatile content released more HCN. The yield of NH₃ was the highest at 800°C during pyrolysis and gasification. And the yield of NH₃ from gasification in steam/Ar was far higher than that from gasification in CO₂, where the hydrogen radicals play a key role. Nitrogen retained in char was also investigated. The yield of char-N decreased with an increase of pyrolysis temperature. Vitrinite from lower rank coal had lower yield of char-N than that from the high rank coal.     

Kinetic characteristics of in-situ char-steam gasification following pyrolysis of a demineralized coal

This study aims to examine the char-steam reactions in-situ, following the pyrolysis process of a demineralized coal in a micro fluidized bed reactor, with particular focuses on gas release and its kinetics characteristics. The main experimental variables were temperatures (925 °C?1075 °C) and steam concentrations (15%–35% H₂O), and the combination of pyrolysis and subsequent gasification in one experiment was achieved switching the atmosphere from pure argon to steam and argon mixture. The results indicate that when temperature was higher than 975 °C, the absolute carbon conversion rate during the char gasification could easily reach 100%. When temperature was 1025 °C and 1075 °C, the carbon conversion rate changed little with steam concentration increasing from 25% to 35%. The activation energy calculated from shrinking core model and random pore model was all between 186 and 194 kJ/mol, and the fitting accuracy of shrinking core model was higher than that of the random pore model in this study. The char reactivity from demineralized coal pyrolysis gradually worsened with decreasing temperature and steam partial pressure. The range of reaction order of steam gasification was 0.49–0.61. Compared to raw coal, the progress of water gas shift reaction (CO + H₂O ? CO₂ + H₂) was hindered during the steam gasification of char obtained from the demineralized coal pyrolysis. Meanwhile, the gas content from the char gasification after the demineralized coal pyrolysis showed a low sensitivity to the change in temperature.     

Investigation into kinetic compensation effects for the production of hydrogen-rich gas during gasification of sub-bituminous coal char in varying gas environments

This study has focused on the evolution of kinetic parameters, i.e., E_app and lnA_app and kinetic compensation effects (KCE) of char consumption and CO, CO?, and H? formation during gasification of Collie coal char in varying gas environments (15%H?O–Ar, 8%H?O–Ar, and 0.4%O?+8%H?O–Ar). The instantaneous rate was obtained continuously during experiments by measuring the product gas composition using a quadrupole mass spectrometer. Observed variations of E_app, lnA_app, and the extent of KCE suggest that the decrease in steam partial pressure from 15%H?O to 8%H?O surrounding the coal char particles appears to affect the path of CO? and H? formation from surface water-gas shift (WGS) reaction in 15%H?O–Ar to char-H?O heterogeneous reaction in 8%H?O–Ar, at higher conversion (conversion >0.5). However, H? formation displays strong KCE and increased H? molar flux in 0.4%O?+8%H?O–Ar when compared to gasification of char with steam only (8%H?O–Ar and 15%H?O–Ar). In contrast, the introduction of 0.4%O? to 8%H?O–Ar dominates the char gasification with only consumption of carbon active sites present on the char surface. That resulted in weak KCE for char consumption and decreased CO/CO? (molar flux ratio) compared to the gasification of char in 15%H?O–Ar and 8%H?O–Ar. Furthermore, the results indicate that the residual char obtained from the faster diffusion-controlled char-O? heterogeneous reaction in the 0.4%O?+8%H?O–Ar acts as an activated char precursor for subsequent kinetics-controlled char-H?O heterogeneous reactions. This enhances the migration of H radicals generated from the H?O molecule to the inner char matrix in 0.4%O?+8%H?O–Ar with an increased H? formation rate than gasification of char with steam only.     

碳焦结构的电镜分析及其分形描述

本文对从沉降炉及电厂煤粉炉中获得的煤粉碳焦进行扫描电镜观察和分析，发现了孔洞结构的自相似性并提出可以用分形模型来描述碳焦孔洞结构。初步研究结果表明分形特征与碳焦燃烧工况有关。按分形模型计算的孔洞容积与实测结果符合较好。     

Co-gasification reactivity of petroleum coke with coal and coal liquefaction residue

In this work, experimental study on co-gasification of petroleum coke with coal and coal liquefaction residue (CLR) under CO₂ atmosphere was investigated in a temperature-programmed reactor. The effect of ashes from coal/CLR and metallic oxide on gasification reactivity of petroleum coke was also investigated. The calculated and experimental gasification conversion was compared to analysis the synergetic effect during co-gasification. The results indicated that the petroleum coke has a much lower reactivity than that of coal/CLR chars, while it can be greatly improved by co-gasifying with coal/CLR. The synergetic effect on co-gasification of petroleum coke with coal/CLR was presented as the progress of co-gasification reaction. It was found that the synergetic effect can be enhanced with increasing coal proportion. However, as the increase of coal rank, the synergetic effect gradually weakened during the co-gasification process. In the selected coal/CLR samples, the low rank coal and CLR exhibited a better effect when co-gasifying with petroleum coke. The difference of synergetic effect was probably attributed to the catalytic effect of mineral matters in different coal/CLR. According to composition analyses of various ashes and the co-gasification reactivity of samples, it can be concluded that high content of active components such as Ca- and Fe-in coal/CLR was beneficial to co-gasifying with petroleum coke, while high content of inert Si- and Al- components in coal tended to resist the reaction.     

Fundmental aspects of catalysed coal char gasification

A brief review of the basic aspects of catalysed coal char gasification is presented. Kinetics and mechanisms of catalysed and uncatalysed gasification reactions of coal char with steam, carbon dioxide and hydrogen are discussed. Mass transport effects and internal structure of coals are shown to be important in determining rates of these reactions. the importance of the type of catalyst used is also discussed. Such factors as catalyst cations and anions, the method by which the catalyst is contacted with the coal char, and physical and chemical states of the catalyst both prior to and during reaction are shown to be important in the gasification process. Finally, research instruments and equipment used recently for studies in catalysed gasification are reviewed. These include various types of reactor systems for following the course of these reactions and analytical instruments for assessing the physical and/or chemical state of the catalysts and/or coal char both prior to and during the gasification reactions.     

Circulating fluidized bed gasification of low rank coal: Influence of O<Subscript>2</Subscript>/C molar ratio on gasification performance and sulphur transformation

To promote the utilization efficiency of coal resources, and to assist with the control of sulphur during gasification and/or downstream processes, it is essential to gain basic knowledge of sulphur transformation associated with gasification performance. In this research we investigated the influence of O₂/C molar ratio both on gasification performance and sulphur transformation of a low rank coal, and the sulphur transformation mechanism was also discussed. Experiments were performed in a circulating fluidized bed gasifier with O₂/C molar ratio ranging from 0.39 to 0.78 mol/mol. The results showed that increasing the O₂/C molar ratio from 0.39 to 0.78 mol/mol can increase carbon conversion from 57.65% to 91.92%, and increase sulphur release ratio from 29.66% to 63.11%. The increase of O₂/C molar ratio favors the formation of H₂S, and also favors the retained sulphur transforming to more stable forms. Due to the reducing conditions of coal gasification, H₂S is the main form of the released sulphur, which could be formed by decomposition of pyrite and by secondary reactions. Bottom char shows lower sulphur content than fly ash, and mainly exist as sulphates. X-ray photoelectron spectroscopy (XPS) measurements also show that the intensity of pyrite declines and the intensity of sulphates increases for fly ash and bottom char, and the change is more obvious for bottom char. During CFB gasification process, bigger char particles circulate in the system and have longer residence time for further reaction, which favors the release of sulphur species and can enhance the retained sulphur transforming to more stable forms.     

Modelling and experimental investigations on gasification of coarse sized coal char particle with steam

The steam gasification characteristics of coal char produced two sub-bituminous coals of different origin have been investigated through modelling and experiments. The gasification experiments are carried out in an Isothermal mass loss apparatus over the temperature range of 800–900 °C using a gas mixture of 65% steam and 35% N₂. A fully transient single particle gasification model, based on the random pore model, is developed incorporating reaction kinetics, heat and mass transport inside the porous char particle and the gas film. Stefan-Maxwell equation and Knudson diffusion are incorporated in the multi-component diffusion of species and pore diffusion. The model is validated with the experimental data of the present authors as well as that reported in the literature. The particle centre temperature is found to increase, then decrease and increase again to reach the reactor temperature finally, and the trend is more prominent for the larger particles. The pore opening phenomenon is more evident in SBC2 char, leading to a final char porosity of 0.65 vis-à-vis 0.52 in SBC1 and making it more reactive. Temporal evolution of contours of carbon conversion and concentration of other gaseous species like steam, H₂O, H₂, CO and CO₂ in the particle are computed to investigate the gasification process. A higher temperature is found to favour both the rate peak and the total production of H₂ for both the chars. The total H₂ production from SBC2 char is found to be 0.0189 mol and 0.0236 mol at 800 and 850 °C, while the same for SBC1 char is0.0232 mol and 0.0290 mol respectively. The reaction follows the shrinking core model at the outset, shifting to the shrinking reactive core model subsequently.     

Effect of CO2 and steam gasification reactions on the oxy-combustion of pulverized coal char

For oxy-combustion with flue gas recirculation, elevated levels of CO₂ and steam affect the heat capacity of the gas, radiant transport, and other gas transport properties. A topic of widespread speculation has concerned the effect of gasification reactions of coal char on the char burning rate. To asses the impact of these reactions on the oxy-fuel combustion of pulverized coal char, we computed the char consumption characteristics for a range of CO₂ and H₂O reaction rate coefficients for a 100 μm coal char particle reacting in environments of varying O₂, H₂O, and CO₂ concentrations using the kinetics code SKIPPY (Surface Kinetics in Porous Particles). Results indicate that gasification reactions reduce the char particle temperature significantly (because of the reaction endothermicity) and thereby reduce the rate of char oxidation and the radiant emission from burning char particles. However, the overall effect of the combined steam and CO₂ gasification reactions is to increase the carbon consumption rate by approximately 10% in typical oxy-fuel combustion environments. The gasification reactions have a greater influence on char combustion in oxygen-enriched environments, due to the higher char combustion temperature under these conditions. In addition, the gasification reactions have increasing influence as the gas temperature increases (for a given O₂ concentration) and as the particle size increases. Gasification reactions account for roughly 20% of the carbon consumption in low oxygen conditions, and for about 30% under oxygen-enriched conditions. An increase in the carbon consumption rate and a decrease in particle temperature are also evident under conventional air-blown combustion conditions when the gasification reactions are included in the model.     

On the influence of the char gasification reactions on NO formation in flameless coal combustion

Flameless combustion is a well known measure to reduce NO_x emissions in gas combustion but has not yet been fully adapted to pulverised coal combustion. Numerical predictions can provide detailed information on the combustion process thus playing a significant role in understanding the basic mechanisms for pollutant formation. In simulations of conventional pulverised coal combustion the gasification by CO₂ or H₂O is usually omitted since its overall contribution to char oxidation is negligible compared to the oxidation with O₂. In flameless combustion, however, due to the strong recirculation of hot combustion products, primarily CO₂ and H₂O, and the thereby reduced concentration of O₂ in the reaction zone the local partial pressures of CO₂ and H₂O become significantly higher than that for O₂. Therefore, the char reaction with CO₂ and H₂O is being reconsidered. This paper presents a numerical study on the importance of these reactions on pollutant formation in flameless combustion. The numerical models used have been validated against experimental data. By varying the wall temperature and the burner excess air ratio, different cases have been investigated and the impact of considering gasification on the prediction of NO formation has been assessed. It was found that within the investigated ranges of these parameters the fraction of char being gasified increases up to 35%. This leads to changes in the local gas composition, primarily CO distribution, which in turn influences NO formation predictions. Considering gasification the prediction of NO emission is up to 40% lower than the predicted emissions without gasification reactions being taken into account.     

Detailed kinetic analysis and modelling of the dry gasification reaction of olive kernel and lignite coal chars

The dry gasification process of solid fuels is a promising pathway to mitigate and utilize captured CO₂ emissions toward syngas generation with tailored composition for several downstream energy conversion and chemical production processes. In the present work, comprehensive kinetic analysis and reaction modelling studies were carried out for olive kernel and lignite coal chars gasification reaction using pure CO₂ as gasifying agent. Chars reactivity and kinetics of the gasification reactions were thoroughly examined by thermogravimetric analysis at three different heating rates and correlated with their physicochemical properties. The reactivity of olive kernel char, as determined by the mean gasification reactivity and the comprehensive gasification characteristic index, S, was almost three times higher compared to that of the lignite coal char. It was disclosed that the fixed carbon content and alkali index (AI) have a major impact on the reactivity of chars. The activation energy, E_a, estimated by three different model-free kinetic methods was ranged between 140 and 170 kJ/mol and 250–350 kJ/mol for the olive kernel and lignite coal chars, respectively. The activation energy values for the lignite coal char significantly varied with carbon conversion degree, whereas this was not the case for olive kernel char, where the activation energy remained essentially unmodified throughout the whole carbon conversion range. Finally, the combined Malek and Coats-Rendfrem method was applied to unravel the mechanism of chars-CO₂ gasification reaction. It was found that the olive kernel char-CO₂ gasification can be described with a 2D-diffusion mechanism function (D2) whereas the lignite coal char-CO₂ gasification follows a second order chemical reaction mechanism function (F2).     

Aggregating structure in coal water slurry studied by eDLVO theory and fractal dimension

Coal water slurry gasification is a main source of hydrogen in the developing hydrogen economy. Moreover, biomass and waste can be added, making gasification process greener. To expand the application of coal water slurry and gasification process, it is necessary to understand the micro-structure in this large particle suspension system. In this paper, the micro-structure in coal water slurry was studied by extended DLVO (eDLVO) theory and fractal dimension, which is used to explain the mechanism of stability in large particle suspension systems. The interaction between two coal particles was characterized from the interparticle potential and energy barrier based on the eDLVO theory. The rheology and stability between different types of coals are measured and explained by the aggregating structure and fractal dimension in coal water slurry. The results indicated that there would be an aggregating structure in high rank coals, due to the interparticle potential caused by the surface properties, but probably not in low rank coals. This aggregating structure can be described and characterized by fractal dimension. The aggregation of particles is the source of the stability for high rank coals, as the close-packed 3D network structure in large particle suspension can support coal particles from settling down. The results have demonstrated that the combination of the eDLVO theory and rheological measurement is an effective way to investigate the stability of large particle suspension systems.     

炭化气氛对黑液煤浆及不同煤种气化反应特性的影响

煤气化前阶段的炭化气氛(温度、时间)影响到煤焦的气化反应特性.采用不同的炭化温度和炭化时间制备了黑液水煤浆、普通水煤浆以及其他5种煤的焦样,得到了各种煤焦气化反应的碳转化率;同时,通过扫描电子显微镜分析手段鉴别焦炭表面孔隙分布情况.试验结果表明,相同炭化气氛下得到的7种不同煤焦中,黄陵煤焦的气化活性最高,说明煤化程度越高反应性越低;由于黑液中有机物和无机物钠盐的影响,黑液水煤浆焦的气化特性高于普通水煤浆焦和新汶煤焦.煤焦的气化反应性,不仅与煤阶有关,还和煤焦中含氧官能团和无机化合物的含量有关,同时煤浆中外在添加的无机物组分也影响到煤焦的气化活性.