Optimizing hydrogen gas production from genetically modified rice straw by steam co-gasification.

Future sustainability visions include clean, renewable energy from hydrogen, which can be produced, among other ways, by biomass steam gasification. This study explores strategies addressing the limitations in steam co-gasification of herbaceous biomass, using Monster-TUAT1 rice straw, a genetically modified rice plant with a taller and bigger stalk developed by Tokyo University of Agriculture and Technology (TUAT), and Giant Miscanthus, a promising energy crop, as the feedstock. Firstly, compared with the typical rice straw, the Monster TUAT1 demonstrated superior steam gasification performance with a 1.75 times higher hydrogen gas yield and 27.0 % less tar generation. With a focus on overcoming the challenges posed by high silica content in the Monster TUAT1, co-gasification of it with an energy crop of Giant Miscanthus was performed. However, even under the optimum operation condition (750 °C, steam flowrate: 0.15 g/min), the hydrogen gas yield was only 29.3 mmol/g-C with a tar yield of 27.6 %wt. and a carbon conversion efficiency of 45.9 %, which is deemed unsatisfactory for hydrogen production. Thus, strategies for enhancement were proposed, including the incorporation seaweed biochar with high alkali and alkaline earth species, calcined scallop shell powder, and alkali metal salt into the gasifier. Consequently, the introduction of 10 %wt. of calcined scallop shell resulted in an increase in H2 yield to 37.0 mmol/g-C and 24.3 % CO2 reduction. The addition of alkali metal salt led to 43.9 % increase of H2 product with a 15 %wt. tar yield. The most significant improvement occurred with the introduction of seaweed biochar at 50 %wt., increasing of the hydrogen gas yield to 62.0 mmol/g-C with 86 % of carbon conversion efficiency and tar reduction to 5.5 %. These findings demonstrate the viability of utilizing herbaceous biomass such as rice straw in conjunction with the strategic solutions of co-gasification to overcome constraints in improving hydrogen production.

Synergistic catalytic mechanism of red mud in the co-gasification of spirit-based distillers' grains and sewage sludge.

Experiments of co-gasification of spirit-based distillers' grains (SDG) and sewage sludge (SS) were carried out with red mud (RM) by using a self-designed fixed-bed gasifier. The effects of RM addition, gasification reaction temperature, SS and SDG blending ratio and other factors on the gasification reaction characteristics and synergism were investigated. The results are as follow: RM had catalytic effect on SS and SDG co-gasification, which can enhance the gasification reaction and H2 yield; increasing the temperature can enhance the gasification reaction and reduce the syngas H2/CO; with the increase of SDG, the H2 yield gradually grew; with the rise of SS, the gasification reaction gradually augmented. The catalytic mechanism was mainly due to the redox cycle of Fe2O3 in RM, which can promote the water transfer reaction. At the same time, the eutectic mixture of K, Na, Ca, Fe and other metal elements at high temperatures was the main reason for the synergistic effect.

Unraveling the intrinsic mechanism behind the retention of arsenic in the co-gasification of coal and sewage sludge: Focus on the role of Ca and Fe compounds.

Minimizing the emission of arsenic (As) is one of the urgent problems during co-gasification of Shenmu coal (SM) and sewage sludge (SS). The intrinsic mechanism of As retention was obtained by analyzing the effect of different SM addition ratios on the As form transformation during co-gasification at 1000 °C under CO2 atmosphere. The results showed that the addition of SM effectively promoted the enrichment of As in the co-gasified residues. Especially, the best As retention rate of 65.71% was achieved with the 70 wt% addition ratio of SM. The addition of SM promoted the adsorption and chemical oxidation of As(III) to the less toxic As(V) through the coupling of Ca and Fe compounds in the co-gasified residues. XRD and XPS results indicated that Fe2O3 adsorbed As2O3(g) after partial conversion to Fe3O4 by the Boudouard reaction, while part of As2O3 was oxidized to As2O5 by lattice oxygen. Finally, the generated As2O5 was successively trapped by CaO and Fe2O3 to form stable Ca3(AsO4)2 and FeAsO4. HRTEM and TEM analysis comprehensively proved that As(III) was stabilized by the lattice cage of CaAl2Si2O8. In conclusion, the co-oxidation of Ca and Fe compounds and lattice stabilization simultaneously played a crucial role in the retention of As2O3(g) during co-gasification.

Co-gasification of biomass and oil shale under CO2 atmosphere: Comparative analysis of fixed-bed reactor, gas chromatography and thermogravimetric analysis coupled with mass spectroscopy (TGA-MS).

Co-gasification of biomass with oil shale offers potential for integrating renewable and fossil energy sources, reducing reliance on fossil fuels. Biomass (pine and birch wood and bark) and oil shale blends (10-30 wt%) were gasified under CO2 conditions using thermogravimetric analysis coupled with mass spectrometry (TGA-MS), fixed-bed reactor, and gas chromatography. Results revealed an interaction between oil shale and biomass, enhancing CO and CH4 concentrations in the producer gas. Bark samples demonstrated higher CO concentrations compared to wood samples, particularly in pine, with 16.1 vol% and 5.4 vol%, respectively. While birch wood showed increased H2 evaporation in TGA-MS experiments, oil shale's impact on H2 concentration was inhibitive, as shown by quantitative analysis. Pine bark, with a threefold catalytic index compared to other biomass samples, demonstrated the highest total gas concentrations (19.2 vol%). Interestingly, pine bark char blends exhibited the lowest surface areas (up to 434 m2/g) among the tested samples.

Optimization of syngas production from co-gasification of palm oil decanter cake and alum sludge: An RSM approach with char characterization.

The study explores co-gasification of palm oil decanter cake and alum sludge, investigating the correlation between input variables and syngas production. Operating variables, including temperature (700-900 °C), air flow rate (10-30 mL/min), and particle size (0.25-2 mm), were optimized to maximize syngas production using air as the gasification agent in a fixed bed horizontal tube furnace reactor. Response Surface Methodology with the Box-Behnken design was used employed for optimization. Fourier Transformed Infra-Red (FTIR) and Field Emission Scanning Electron Microscopic (FESEM) analyses were used to analyze the char residue. The results showed that temperature and particle size have positive effects, while air flow rate has a negative effect on the syngas yield. The optimal CO + H2 composition of 39.48 vol% was achieved at 900 °C, 10 mL/min air flow rate, and 2 mm particle size. FTIR analysis confirmed the absence of C─Cl bonds and the emergence of Si─O bonds in the optimized char residue, distinguishing it from the raw sample. FESEM analysis revealed a rich porous structure in the optimized char residue, with the presence of calcium carbonate (CaCO3) and aluminosilicates. These findings provide valuable insights for sustainable energy production from biomass wastes.

Correlation between Flow Temperature and Average Molar Ionic Potential of Ash during Gasification of Coal and Phosphorus-Rich Biomass.

The co-gasification of biomass and coal is helpful for achieving the clean and efficient utilization of phosphorus-rich biomass. A large number of alkali and alkaline earth metals (AAEMs) present in the ash system of coal (or biomass) cause varying degrees of ash, slagging, and corrosion problems in the entrained flow gasifier. Meanwhile, phosphorus is present in the slag in the form of PO43-, which has a strong affinity for AAEMs (especially for Ca2+) to produce minerals dominated by calcium phosphates or alkaline Ca-phosphate, effectively mitigating the aforementioned problems. To investigate the changing behavior of the slag flow temperature (FT) under different CaO/P2O5 ratios, 72 synthetic ashes with varying CaO/P2O5 ratios at different Si/Al contents and compositions were prepared, and their ash fusion temperatures were tested. The effects of different CaO/P2O5 ratios on the FT were analyzed using FactSage thermodynamic simulation. A model for predicting slag FT at different CaO/P2O5 ratios was constructed on the basis of the average molar ionic potential (Ia) method and used to predict data reported from 19 mixed ashes in the literature. The results showed that Ia and FT gradually increased with a decreasing CaO/P2O5 ratio, and the main mineral types shifted from anorthite → mullite → berlinite, which reasonably explained the decrease in ash fusion temperatures in the mixed ash. The established model showed good adaptability to the prediction of 19 actual coal ash FTs in the literature; the deviation of the prediction was in the range of 40 °C. The model proposed between FT and Ia based on the different CaO/P2O5 ratios can be used to predict the low-rank coal and phosphorus-rich biomass and their mixed ashes.

Co-gasification of rural solid waste and biomass in rural areas: Simulation and plant-scale process.

Co-gasification technology is considered to be one of the most potential technologies for solid waste treatment, and the co-gasification treatment of rural solid waste (RSW) and biomass can effectively promote waste reduction and resource utilization. In the present study, the co-gasification of RSW and biomass in an updraft fixed bed gasifier was simulated using the Aspen Plus software, where the simulation results were validated via plant-scale experiments. In this scenario, the impacts of biomass source (i.e., rice husk, rice straw, tree bark and corn straw), co-gasification ratio (CGR) (0-40%) and air equivalence ratio (AER) (0.30-0.55) on the performance of the fixed-bed were investigated. Results showed that Aspen Plus could describe the plant-scale co-gasification process well. Besides, the tree bark-RSW system had the highest heat conversion efficiency of 6.00 MJ/kg the simulation temperature of the gasification layer increased greatly from 485 to 913 °C when the AER increased from 0.40 to 0.55. In addition, the co-gasification of RSW and tree bark could achieve the highest efficiency at the AER of 0.45 and CGR of 20% w, in which the gasification temperature reached 799 °C with the gasification efficiency of 57.17%. This study explored the use of co-gasification of RSW and biomass in rural areas by simulation and plant-scale processes, which promotes the commercial application of co-gasification technology and contributes to sustainable waste management in rural areas.

Energy recovery from agro-forest wastes through hydrothermal carbonization coupled with hydrothermal co-gasification: Effects of succinic acid on hydrochars and H2 production.

Aiming to upgrade agro-forest wastes into value-added solid and gaseous fuels in the present investigation, hydrothermal carbonization (HTC) of spruce (SP), canola hull (CH), and canola meal (CM) was optimized in terms of operating conditions, maximizing the higher heating value of hydrochars. The optimal operating conditions were achieved at HTC temperature, reaction time, and solid-to-liquid ratio of 260 °C, 60 min, and 0.2 g mL-1, respectively. At the optimum condition, succinic acid (0.05-0.1 M) was used as HTC reaction medium to investigate the effects of acidic medium on the fuel characteristics of hydrochars. The succinic acid assisted HTC was found to eliminate ash-forming minerals e.g., K, Mg, and Ca from hydrochar backbones. The calorific values, H/C and O/C atomic ratios of hydrochars were in the range of 27.6-29.8 MJ kg-1, 0.8-1.1, and 0.1-0.2, respectively, indicating the biomass upgrading into coal-like solid fuels. Finally, hydrothermal gasification of hydrochars with their corresponding HTC aqueous phase (HTC-AP) was assessed. Gasification of CM resulted in a relatively high H2 yield of 4.9-5.5 mol kg-1 followed by that for SP with 4.0-4.6 mol H2 per kg of hydrochars. Results suggest that hydrochars and HTC-AP have a great potential for H2 production via hydrothermal co-gasification, while suggesting HTC-AP reuse.

Gasification characteristics and synergistic effects of typical organic solid wastes under CO2/steam atmospheres.

Gasification technology is an effective way to achieve efficient, safe, and resourceful disposal of organic solid wastes (OSWs). Due to the complex sources and variable components of the OSWs, the co-disposal is highly essential. Various typical OSWs, including food waste (cooked rice, CR), agricultural waste (rice husk, RH; sugarcane bagasse, SB), and industrial waste (furfural residue, FR), were selected for this study. The gasification characteristics and synergistic performance were examined in terms of thermal weight loss characteristics under the CO2 atmosphere and gaseous product characteristics under the steam atmosphere. The synergistic indices of performance parameters were introduced to quantify the synergistic effects. The gasification activity of FR was remarkably higher than that of other OSWs. In the co-gasification with CR under the CO2 atmosphere, FR played an excellent positive synergistic effect, but the agricultural wastes played a slight or no synergistic effect. In the steam co-gasification, RH, SB, and FR all promoted the generation of syngas, in which FR showed still significant synergistic effects, with the synergistic indices of H2 yield, syngas yield, CCE, and CGE being 4-12 times higher than those of other blended wastes. The excellent performance of FR in (co-)gasification was mainly attributed to the acidic properties of FR, which was confirmed by comparing the (co-)gasification performance of FR with and without water-washing pretreatment. The work provides guidance for the co-disposal of OSWs in industrial applications.

Effects of steam and CO2 on gasification tar composition and evolution of aromatic compounds.

The removal of tar is conducive to improving the energy efficiency of downstream equipment and reducing the damage caused to it. In this study, a two-stage continuous feeding apparatus was developed to explore the yield and characteristics of tar produced from the co-gasification of microcrystalline cellulose (MCC) and polyethylene (PE) under separate and mixed atmospheres of steam and CO2. The tar yield can effectively reduce to 2.27 % when the steam and feedstock mass ratio (S/F) is 0.8. CO2 can partially substitute the steam in the gasification process, which can effectively promote a decrease in benzofuran. Furthermore, Gaussian software was employed to analyze the evolution mechanism of aromatic compounds. When the temperature is more than 800 °C, hydrogen consumption in the benzene cracking process is reduced, which is instrumental in improving the quality of syngas. Naphthalene is prone to form through the recombination of two cyclopentadienyls. Controlling the cyclization of cyclopentadienyls is a critical step in reducing the formation of polycyclic aromatic hydrocarbons. H and OH radicals are critical in phenol and benzofuran cracking, respectively. Although radicals act differently on specific aromatic compounds, the gasification effect of CO2 is less than that of steam because steam can provide both H and OH radicals, whereas CO2 needs to consume H radicals to generate OH radicals. The results provide beneficial guidance for controlling tar formation.

Low-emission and energetically efficient co-gasification of coal by incorporating plastic waste: A modeling study.

The issues of global plastic waste generation and demand for hydrogen energy can be simultaneously resolved by gasification process. In this regard, feasibility and efficiency of steam and air co-gasification of coal by incorporating five different and prevalent types of plastic waste were investigated in this modeling study. All steam and air coal/plastic waste co-gasification types were multi-objective optimized utilizing a response surface methodology. The best co-gasification types were selected using VIekriterijumsko KOmpromisno Rangiranje (VIKOR) analysis. Overall, the results showed that incorporating plastic waste into coal gasification improved hydrogen concentration in the syngas and increased normalized carbon dioxide production due to the high carbon content of plastic waste and activation of water-gas and CO shift reactions. VIKOR analysis revealed that steam coal/low density polyethylene was the best optimized co-gasification type with hydrogen concentration of 62.8 mol %, normalized carbon dioxide production of 2.60 g/mol, based on the feedstock entering the system, and energy efficiency of 76.6%. Increasing gasifier temperature enhanced hydrogen concentration and decreased normalized carbon dioxide production. The energy efficiency was markedly improved by increasing the moisture content and decreasing the ratio of steam/feedstock. This study confirmed the hypothesis of efficient utilization of plastic waste in coal/plastic waste co-gasification.

Synergistic effect of the cotton stalk and high-ash coal on gas production during co-pyrolysis/gasification.

The synergistic effect of the cotton stalk (CS) and the high-ash coal (HAC) on the gas production in the co-pyrolysis/gasification processes was studied using the newly designed quartz boat in this work. The gas yield and the concentrations of main gas components were quantitatively compared between the co-pyrolysis/gasification and the individual pyrolysis/gasification. The results showed that the gas yield during the co-pyrolysis was promoted at 950℃. There was almost no interaction between CS and HAC, since the co-pyrolytic gas yield exhibited a linear relationship with CS mixing ratio of 20% to 60%. The catalytic effect of alkali metals and alkaline earth metals that existed in CS, was enhanced by the addition of steam, and the synergistic effect was reduced while gas yield was enhanced with CS blending ratio increasing during co-gasification. The results provided a method to enhance synergistic effect between biomass and coal during co-pyrolysis/gasification in this study.

Hydrogen-rich gas production from steam co-gasification of banana peel with agricultural residues and woody biomass.

Steam co-gasification of banana peel with other biomass, i.e., Japanese cedar wood, rice husk and their mixture, was carried out for the hydrogen-rich gas production in a fixed-bed reactor. For the co-gasification process, the banana peels were physically mixed with rice husk, Japanese cedarwood and their mixture respectively by different mixing weight ratios. The effects of reaction temperature and the addition amount of banana peel on the gas production yield were investigated by comparing the experimental data with the calculated ones based on the individual biomass gasification at the same condition. It was found that the banana peel with a high content of alkali and alkaline earth metal (AAEM) species exhibited not only high gasification reactivity but also a significant enhancing catalytic effect on the co-gasification process at the low temperature, especially with the biomass containing no silica species. The high content of silica species in the rice husk had a negative effect on the gasification reactivity of banana peel during the co-gasification since it could hinder the release of AAEM from the biomass and/or lead to the possible formation of inactive alkaline silicates. However, the combination of these three samples with the suitable weight ratio could improve the gasification performance at the low temperature due to the synergetic effect provided by high contents of potassium and calcium from banana peel and cedarwood respectively. Moreover, the addition of calcined seashells as the CaO source could further improve the gas production yield, especially the hydrogen gas yield at a relatively low gasification temperature of 750 ℃.

Gasification of refuse-derived fuel from municipal solid waste for energy production: a review.

Dwindling fossil fuels and improper waste management are major challenges in the context of increasing population and industrialization, calling for new waste-to-energy sources. For instance, refuse-derived fuels can be produced from transformation of municipal solid waste, which is forecasted to reach 2.6 billion metric tonnes in 2030. Gasification is a thermal-induced chemical reaction that produces gaseous fuel such as hydrogen and syngas. Here, we review refuse-derived fuel gasification with focus on practices in various countries, recent progress in gasification, gasification modelling and economic analysis. We found that some countries that replace coal by refuse-derived fuel reduce CO2 emission by 40%, and decrease the amount municipal solid waste being sent to landfill by more than 50%. The production cost of energy via refuse-derived fuel gasification is estimated at 0.05 USD/kWh. Co-gasification by using two feedstocks appears more beneficial over conventional gasification in terms of minimum tar formation and improved process efficiency.

Gas-pressurized torrefaction of biomass wastes: Co-gasification of gas-pressurized torrefied biomass with coal.

Co-gasification of coal and biomass offers a relatively cleaner utilization way of fossil fuel. The fuel property improvement of biomass can not only improve the property of syngas but also enhance the synergistic effect during the co-gasification. In our previous work, a novel gas-pressurized (abbreviated as GP) torrefaction was proposed to effectively upgrade the biomass under mild condition. In this work, the co-gasification of GP torrefied biomass and coal were conducted to explore the synergistic effect and kinetics. Significant synergistic effect during the co-gasification was proved. The CO yield of co-gasification increased to as high as 70.70 mol/kg, resulting from the promotion of carbon in coal converting into CO by GPRS. Furthermore, the kinetic model of RPM was most fitting for the co-gasification, and the activation energy of co-gasification was reduced. Thus, the coal gasification was promoted significantly by GP torrefied biomass through obvious synergistic effect during the co-gasification.

Evaluation of the energy generation potential by an experimental characterization of residual biomass blends from Córdoba, Colombia in a downdraft gasifier.

An experimental characterization of crop residue biomass blends to evaluate their energy potential was conducted using an experimental approach in a commercial scale downdraft gasifier. Corncobs, rice husks, sesame stalks and cotton gin refuse were used to study the effect of mixture proportions on equivalence ratio, gasification temperature, syngas lower heating value (LHV), and cold gas efficiency (CGE). Using an experimental mixture design, thirty-two sample blends were evaluated in an Ankur WBG-30 downdraft gasifier with 30 kg/h feed supply coupled with a syngas purification system, temperature sensors and a gas chromatograph. Syngas composition CO, H2, CH4, N2 and CO2 are presented for each blend. It was found that temperature, syngas composition, syngas lower heating value and cold gas efficiency were negatively affected as the proportion of rice husks in the mixture was increased. It was possible to reach CGE values up to 57.91% and LHV up to 4460 kJ/kg under certain blending conditions. A higher percentages of rice husks caused a considerable increase in the variability of the equivalence ratio resulting in suboptimal gasification conditions.

Synergistic effect, kinetic and thermodynamics parameters analyses of co-gasification of municipal solid waste and bituminous coal with CO2.

Co-gasification of municipal solid waste (MSW) with bituminous coal (BC) is an attractive alternative to realize the harmless disposal and energy harvesting of MSW. In this work, co-gasification characteristics and synergistic interaction of MSW and BC with CO2 atmosphere are studied by thermogravimetric method, including analyses of thermodynamics, kinetic parameters and reaction mechanism function. Results indicate that MSW gasification process can be divided into four main stages, and that of BC has only three main stages. Gasification temperature of coal char is much higher than that of MSW char, and addition of MSW can significantly improve the gasification reactivity of BC. Besides, a significant synergistic effect is observed for all the blends in char gasification stage. Based on three kinetic methods of Flynn-Wall-Ozawa (Xie et al., 2018), Starink (Zhang et al., 2019a) and Friedman, the minimum average activation energy Ea (184.13 kJ/mol) is obtained when the blend ratio of BC is 40% which might be an optimal option for co-gasification of the blends. The average values of the enthalpy, the Gibbs function and the entropy changes for sample 60MSW40BC are 176.82 kJ/mol, 257.89 kJ/mol and -89.16 J/mol·K, respectively. According to the Malek method, F6, A1 and D7 models are probably more suitable to describe three main stages of sample 60MSW40BC CO2 co-gasification.

Apparent Kinetics of Co-Gasification of Biomass and Vacuum Gas Oil (VGO).

This communication reports the beneficial effects of co-gasification of biomass and residual oil to produce syngas. In this regard, various blends of glucose (a biomass surrogate) to vacuum gas oil (VGO) have been employed to investigate the synergic effects on the gasification process. The non-isothermal co-gasification experiments were conducted in a thermogravimetric analyzer at different heating rates and gasifying agents. The analysis showed that the co-gasification rate increased with the increase of glucose content in the feedstock. The presence of the oxygen in the biomass molecules helped the overall gasification process. The maximum gasification rate of 42.70 wt/min (DTGmax ) was observed with 25 wt% glucose containing sample. The use of gasifying agents appeared to have some influence, especially during high temperature gasification of the glucose-VGO blends. At a same gasification temperature, the co-gasification rate of glucose-VGO blends were found to be 125.7 wt/min and 98.59 wt%/min for N2 and CO2 , respectively. The kinetics of the co-gasification of glucose-VGO blends was conducted based on modified random pore model using TGA experimental data and implemented in MATLAB. The estimated activation energy and rate constants were found to be consistent to the observed co-gasification rates. The apparent activation energies of co-gasification of VGO/biomass blends with different weight percentages shows values ranging 60.56-48.25 kJ/mol. The kinetics analysis suggested that the addition of biomass helped to increase the reaction rate by lowering the activation energy required for accomplishing the reactions compared with petroleum carbonaceous feedstocks. The reaction rate constants isotherms are plotted to show that the k-values are exhibiting similar trends at moderate heating rates between 20 and 60 °C/min. This remark arises due to the nature of the reactions involved which are considered to be inherently similar in this range of heating rate.

Thermogravimetric investigation on the effect of reaction temperature and blend ratio on co-gasification characteristics of pyrolytic oil distillation residue with biochar.

In this study, the CO2 co-gasification characteristics of pyrolytic oil distillation residue and biochar under different reaction temperatures were investigated by thermogravimetric analyzer (TGA). The influence of blend ratio on co-gasification synergy was adequately characterized by correlating the evolution of chemical structure and active AAEMs. The results indicated that increasing proportion of pyrolytic oil distillation residue could effectively improve gasification reactivity of biochar and enhance synergistic behaviors during co-gasification process, whereas the raising reaction temperature dwindled the enhancement of co-gasification reactivity and mutual promotion between individual samples. Moreover, three gasification kinetic models suggested that the lowest apparent activation energy (181.49~182.72 kJ/mol) among blends was obtained by 70 wt% additions of pyrolytic oil distillation residue. Furthermore, the results of Raman and ICP-AES analysis well related to the co-gasification synergy. The migration of active AAEMs and evolution of carbon structure had a pronounced influence on synergistic effect as co-gasification reaction progressed.

Synergistic effect of mixing wheat straw and lignite in co-pyrolysis and steam co-gasification.

Co-pyrolysis and steam co-gasification of wheat straw (WS) and lignite coal (LC) were studied in a tube furnace between 700 °C and 900 °C. Synergistic effect in co-pyrolysis is not always apparent. However, with the introduction of H2O vapor, synergetic effect is more obvious. Gas volume generated by co-gasification was higher than the prediction in all cases. Meanwhile, temperature played an important role and had a linear relationship with the excess gas volume when it exceeded 800 °C. These findings can be explained by that sufficient H2O vapor could enhance synergy according raising catalytic effect of alkali and alkaline earth metals (AAEMs), promoting free radical generated and increasing reactivity of half-chars. Moreover, co-gasification of WS and LC with several blending ratios were studied at 850 °C. It found H2O vapor could promote free radical formation stronger with higher ratio of WS during co-gasification, thus showing an enhancing effect on the reactivity of WS-derived chars.