Biomass gasification performance is jointly governed by operating conditions and feedstock properties, making it difficult to distinguish intrinsic operating-parameter effects from feedstock-dependent variations. This study proposes a physically consistent additive decoupling framework for interpretable biomass gasification prediction and targeted syngas quality regulation. Operating parameters and biomass properties are partitioned into separate variable blocks, and cross-domain interactions are progressively introduced according to their importance. This design enables target-dependent coupling requirements to be quantified while preserving a decomposable model structure. Results show that methane and gas yield require only a few critical cross-domain interactions, whereas hydrogen and carbon dioxide are nearly insensitive to such coupling. In contrast, syngas lower heating value on a nitrogen-free basis (LHVg) requires a relatively large subset of cross-domain interactions, and carbon monoxide benefits from more complete interaction modeling. The proposed monotonic additive models achieve full physical conformity for constrained targets while maintaining competitive predictive performance. Relative and absolute three-dimensional response surfaces further connect model interpretation with practical syngas regulation. Response analysis indicates that equivalence ratio primarily defines the feasible operating window, temperature governs dominant reaction pathways, and steam-to-biomass ratio adjusts local component balance. These findings provide differentiated operating strategies for hydrogen-rich syngas production, carbon monoxide retention, methane preservation, and fuel-oriented LHVg optimization. The proposed framework offers a physically consistent and interpretable route for biomass gasification prediction and syngas quality regulation.

A comparative experiment was conducted in a large-scale pig farm in Jiangsu Province, China. Emission characteristics of ammonia (NH3), methane (CH4), and nitrous oxide (N2O) were compared between a pig house with robotic daily manure cleaning (RC) and shallow manure pit storage (MS). The experiment was initiated in the spring of 2024 (April 15th) and concluded on June 14th, with a total duration of 61 days. The results showed no difference in ventilation or indoor temperature during the monitoring period, while pig weights ranged from 30 to 81 kg. Under the RC mode, the average daily concentrations of NH3 and CH4 in-barn concentration were 27% and 46% lower than under the MS mode. The corresponding average daily emission factors were 3.4 and 29.9 g d(-1) pig(-1) for NH3 and CH4, representing reductions of 22% and 46% compared to the MS mode. There was no difference in the emission of N2O (p > 0.05). The RC system significantly reduced in-barn concentrations and emission rates of NH3 and CH4, likely by shortening the manure retention time inside the barn. The study showed that robotic manure removal technology shortens manure storage time by increasing the frequency of manure cleaning, enabling the simultaneous reduction of ammonia and methane emissions. It offers a promising technical approach for mitigating gaseous pollution in large-scale pig production.

Rapid development of the pig industry in China has led to numerous challenges in managing livestock manure and slurry. Field application of slurry has proven to be an economical, effective and environmentally beneficial approach to sustainable resource recycling globally. However, China remains largely dependent on fertilizer inputs from mineral sources, with limited adoption of slurry application practices. A common challenge with slurry field application isits typically higher emission of ammonia and greenhouse gases (GHGs) compared to mineral fertilizers. This work investigated selected treatments with specific ratios of pig slurry and mineral fertilizers aimed at reducing the use of mineral fertilizers and emission following basal fertilizer application and topdressing after maize planting specifically, the ratios of pig slurry included 30%, 50% and 100%. The methods of fertilizer application involved a comparison of acidified versus non-acidified pig slurry for field application, as well as a comparison between sprinkler and drip irrigation. The results showed that replacing 30% of mineral fertilizers with pig slurry (RC30) reduced total GHG emission by 62% and NH3 emission by 60.4% compared to a full slurry substitution during field application. Meanwhile, the RC30 group recorded the lowest total NH3 emission, totaling 5.08 kg & centerdot;ha-1, among all treatments using pig slurry. The acidification of pig slurry significantly reduced NH3emission, decreasing them by 42.1% compared to the direct application of untreated pig slurry. Drip irrigation proved to be more effective in reducing total GHG emission compared to sprinkler irrigation. Drip irrigation reduced NH3emission by 38.9%-42.6%, N2O emission by 12.4%-18.6%, and GHG emission by 21.5%-34.7%. In summary, this study demonstrated that replacing 30% of mineral fertilizers with pre-acidified pig slurry, combined with drip irrigation, reduced GHG and NH3 emission. (c) The Author(s) 2026. Published by Higher Education Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0)

Biomass gasification using laterite nickel ore (LNO) as bed material is helpful to reduce tar yield and improve gasification performance. In this study, the biomass tobacco stalk (TS) gasification experiment was carried out at 650°C in a laboratory-scale fluidized bed reactor using laterite nickel ore as gasification bed material. The effect of mass ratio of bed material to raw material (defined as R) on gasification characteristics was studied. The results show that the addition of LNO significantly enhances the tar cracking reaction during the gasification process; the tar yield decreases; the syngas yield increases, and the components are optimized. When R is 1.62, the maximum effective gas yield is 0.26 m3/kg, and the minimum tar yield is 16.20 mg/kg. With the increase of R, the aromatic properties of tar are weakened; polycyclic aromatic hydrocarbons are transformed into monocyclic aromatic hydrocarbons and alicyclic compounds, and the types of tar components are reduced. These results provide an optimal method for the design of biomass fluidized-bed gasification experiment using laterite nickel ore as bed material.

High moisture content is a key factor contributing to the low calorific value of coal gasification fine slag (CGFS). This low calorific value significantly restricts its combustion utilization. Efficient drying is difficult because a substantial volume of water is adsorbed within the pore structure of CGFS. In this study, a novel deep-drying technology is proposed to efficiently remove this physically bound water, utilizing high-temperature gas flow as the drying medium. Subsequently, the drying characteristics of CGFS associated with this technology were experimentally investigated from three aspects. First, the impact of gas flow temperature on moisture removal efficiency was elucidated. Second, the evolution of water occurrence forms, pore structure, and oxygencontaining functional groups of the dried CGFS was revealed. Finally, pollutant emission characteristics under various gas flow temperatures and drying atmospheres were explored. Results: indicated that increasing the inlet gas flow temperature significantly improved the dehydration efficiency. Specifically, raising the temperature from 591 degrees C to 906 degrees C increased the dehydration efficiency within the dryer from 69.89% to 84.83%. At an initial moisture content of about 50%, water existed in free, physically bound, and chemically bound states. Among these, physically bound water was predominant. The high dehydration efficiency was mainly due to the substantial removal of this physically bound water. Increasing the gas flow temperature increased the porosity of the dried CGFS and decreased its bulk density. Concurrently, hydrophilic functional groups (e.g., carboxyl, carbonyl) diminished. In contrast, hydrophobic groups (e.g., aromatics/alkanes) increased. Both temperature and the drying atmosphere significantly influenced carbon monoxide (CO) concentrations. Under an air atmosphere, CO concentrations rose non-linearly with temperature. In comparison, at equivalent temperatures, CO concentrations were significantly lower under the nitrogen atmosphere. These findings establish a solid foundation for the development of CGFS drying processes.

A self-sustained activation-reduction technology was proposed to achieve non-catalytic CO2 reduction. This study investigates the effects of heat dissipation and ineffective physical sensible heat loss. The results indicate that increased heat dissipation weakens CO2 reduction by suppressing the Boudouard reaction and increasing the required combustion reaction intensity. The corresponding energy loss, exergy destruction and loss primarily originate from CO and solid carbon, respectively. In addition, reducing ineffective physical sensible heat loss enhances CO2 reduction by intensifying the Boudouard reaction. When the outlet temperature of the material stream is relatively low (similar to 400 degrees C) and the proportion of physical sensible heat is minor (<4%), ineffective physical sensible heat primarily affects the energy balance by changing the distribution of chemical energy and heat dissipation. Similarly, its impact on the exergy balance is manifested through the redistribution of chemical exergy, exergy destruction and loss. Substantially increasing the feeding rate of carbon-based material is a promising approach that can elevate the reaction temperature and enhance the reduction of CO2 by solid carbon without significantly increasing energy loss.

Dissolved oxygen (DO) plays a vital role in the emission of carbon-nitrogen gaseous (CNs: NH3, CH4 and N2O) in livestock wastewater, but the effect of different DO concentration on the emission of CNs is yet unclear. In this study, the continuous emission of CNs from swine manure biogas digestate (BD) storage under different DO concentrations was monitored using the dynamic emission vessel method for 60 consecutive days, and the emission mechanism was explored combined with the microbial analysis. Results showed that the cumulative emission fluxes of GHGs in BD with DO concentrations of 1.0, 2.0, and 4.0 mg L- 1 were reduced by 58.66 %, 70.46 %, and 66.81 %, respectively, compared with the static storage BD. Verticia might inhibits the activity of acetoclastic genera (Methanosaeta and Methanosarcina). DO concentrations was positively correlated with the Verticia. Increasing the concentration of dissolved oxygen reduce CH4 emissions. N2O and NH3 emissions were positively correlated with DO concentration, but the total N loss showed the opposite changes. The results of this study provide a deeper insight into the effect of DO concentration on the CNs emission, and an appropriate concentration of 1.0-2.0 mg L- 1 is recommended for the reduction of CNs in swine manure BD.

The pyrolysis behavior exhibited during the coal partial gasification of circulating fluidized bed (CFB) indicates its potential to further increase the pyrolysis efficiency for tar production. To verify and reinforce it, the pyrolysis behaviors of this process at various factors including feeding position, oxygen concentration, and oxygen equivalence ratio were systematically investigated in a bench scale CFB. The distribution and physicochemical properties of gas, liquid, and solid products were focused and the evolution of pyrolysis products was thereby revealed. Experimental results show that raising the coal feeding position reduces the direct contact between coal particles and oxygen, creating a local reduction zone in the upper part of the riser, where the temperature drops sharply. This significantly enhances the pyrolysis effect through protecting the pyrolysis gas from oxidation. In this case, the produced tar is rich in monoaromatic hydrocarbons. Within the oxygen volume concentration range of 21%-33%, increasing the oxygen concentration of the gasifying agent shortens the oxygenated zone in the lower riser, further enhancing the pyrolysis effect. Reducing the oxygen equivalence ratio from 0.19 to 0.13 also results in a higher tar yield. In this study, the maximum tar weight yield reaches 4.97%, accounting for 72.81% of the total tar measured by Gray-King analysis. These results confirm the feasibility of tar production via coal partial gasification in a single CFB.

The inferior flammability of coal gasification fine slag（CGFS） from entrained-flow gasifiers hampers its resourceful utilization.However,the reasons behind its poor flammability still need to be investigated.This paper conducted a comparative study on the combustion characteristics of three CGFS samples:CGFS GSP ,CGFS SN ,and CGFS OMB （subscripts GSP,SN,and OMB representing different gasification processes）,using experimental techniques such as TG/DTG and combustion kinetic model fitting methods.Additionally,a comprehensive investigation into the physicochemical properties of CGFS was conducted.The objective was to elucidate the causes behind the poor flammability of CGFS.The results revealed that CGFS exhibits lower volatile matter content and higher activation energy than their corresponding raw coal（RC）,leading to a significantly higher ignition temperature.The ignition temperatures of RC1,RC2,and RC3 are 361.82℃,378.66℃,and 404.99℃,respectively.In contrast,the ignition temperatures of CGFS GSP CGFS SN ,and CGFS OMB are 549.08℃,566.58℃,and 532.67℃,respectively.During the combustion reaction,the temperature(T max ) at which CGFS reaches its maximum weight loss rate is significantly higher than the temperature(T maxⅢ ) at which fixed carbon in raw coal reaches its maximum weight loss rate.The T maxⅢ of RC1,RC2,and RC3 are 450.90℃,457.19℃,and 452.77℃,respectively.In contrast,the T max of CGFS GSP ,CGFS SN ,and CGFS OMB are 583.55℃,608.20℃,and 582.18℃,respectively.The maximum weight loss rate of different types of CGFS is also significantly lower than the fixed carbon combustion maximum weight loss rate of their respective raw coal samples.The physicochemical characterization results of CGFS demonstrate that,compared to the corresponding raw coal,there is a significant reduction in the proportion of active sites in CGFS.Simultaneously,the proportion of C-C/C-H on the surface of residual carbon in CGFS decreases.In contrast,the proportion of O=C-O significantly increases,suggesting a shift toward a more stable state of carbon-containing functional groups.This study is expected to offer essential theoretical support for the efficient combustion utilization of CGFS.

Atmospheric ammonia (NH3) has multiple impacts on the environment, climate change, and human health. China is the largest emitter of NH3 globally, with the dynamic inventory of NH3 emissions remaining uncertain. Here, we use the second national agricultural pollution source censuses, integrated satellite data, 15N isotope source apportionment, and multiple models to better understand those key features of NH3 emissions and its environmental impacts in China. Our results show that the total NH3 emissions were estimated to be 11.2 ± 1.1 million tonnes in 2020, with three emission peaks in April, June, and October, primarily driven by agricultural sources, which contributed 74% of the total emissions. Furthermore, employing a series of quantitative analyses, we estimated the contribution of NH3 emissions to ecosystem impacts. The NH3 emissions have contributed approximately 22% to secondary PM2.5 formation and a 16.6% increase in nitrogen loading of surface waters, while ammonium deposition led to a decrease in soil pH by 0.0032 units and an increase in the terrestrial carbon sink by 44.6 million tonnes in 2020. Reducing agricultural NH3 emissions in China would contribute to the mitigation of air and water pollution challenges, saving damage costs estimated at around 22 billion US dollars due to avoided human and ecosystem health impacts.

The prospect of fluidized reduction roasting of nickel laterite is promising. However, experimental methods limit the study of the reaction of nickel laterite ore under fluidized conditions. The traditional kinetic model is inadequate in describing the reaction process and the heat and mass transfer mechanism in its entirety. This study proposes a novel approach by employing the micro-fluidized bed thermogravimetric analysis (MFB-TGA) method to investigate the CO reduction of nickel laterite. The effects of temperature, particle size, and reaction gas concentration on the mechanism of CO reduced laterite nickel ore were obtained. A modified pore model, based on the formation and growth of product islands, was developed to explain the reduction kinetics at the level of reaction mechanism. The results show that the process of CO reduction of nickel laterite includes external diffusion of gas, intraparticle diffusion, surface chemical reaction, product island growth, and product layer diffusion. The model calculations agree well with the experimental data with an error of +/- 5 %. Utilizing the empirical formula of Arrhenius, the reaction activation energies were calculated to be 123.55 kJ/mol for ks, 65.52 kJ/mol for hc, and 109.8 5 kJ/mol for Dp. Additionally, the mass-transfer process of nickel laterite ore was discussed, and the effect of particle size on the reduction reaction of nickel laterite ore was obtained to be divided into three characteristic zones. When the particle size is less than 80 mu m, the internal and external mass transfer resistance of the particles is basically negligible. This study provides a reliable basis for the reaction kinetics of fluidized reduced nickel laterite, and the established model can be used as a practical tool to carry out reaction kinetics studies in the field of fluidized metallurgy.

With the scale-up of circulating fluidized bed (CFB) boilers, the size of the platen heating surface within the furnace increases. Deformation, crack, and tube explosion of the platen heating surface threaten the safe and stable operation of CFB boiler. Large wall temperature deviation and overtemperature of partial tubes of heating surfaces are two of main reasons resulting in above problems. To identify the causes of large wall temperature deviation and decrease them, the heat transfer characteristics and wall temperature distribution uniformity of platen superheaters in the furnace of a 350 MWe supercritical CFB boiler were studied by experimental tests, and the structure of the high temperature superheater was optimized by numerical simulation to improve the temperature distribution uniformity. The steam parameters and wall temperatures of the platen superheaters were measured at boiler loads of 50 % BMCR, 75 % BMCR, and 100 % BMCR. The heat transfer coefficient, heat flux, and wall temperature uniformity of the platen superheaters were analyzed. At 100 % BMCR boiler load, the average heat transfer coefficient and heat flux of the medium temperature superheater IIs were 165.5 W/(m2 & sdot;degrees C) and 56 kW/m2, respectively; while those of the high temperature superheaters were 179.7 W/(m2 & sdot;degrees C) and 53.2 kW/m2, respectively. The wall temperature distribution uniformity among six medium temperature superheater IIs or six high temperature superheaters was relative good, while the temperature distribution uniformity of a single platen superheater required improvement. An optimized structure of the high temperature superheater was obtained from eight structures by numerical simulation, achieving a steam temperature deviation of less than 8 degrees C at the boiler load of 100 % BMCR.

Ammonia is indispensable for producing fertilizers that sustain the global population, yet its agricultural application contributes significantly to water pollution. Electrochemical technologies offer a renewable-energy-driven and chemical-free pathway for recovering ammonia directly from wastewater, representing a critical step toward a circular nitrogen economy and net-zero emissions in the wastewater sector. Nevertheless, translating lab-scale advances to industrialization remains constrained by technological hurdles. Emerging electrode-engineering strategies promise scalable, membrane-less electrochemical systems, but a systematic and comparative assessment is lacking. In this review, we first present the electrochemical ammonia recovery pathway and elucidate the mechanisms of various electrode materials in this process. Secondly, we critically evaluate state-of-the-art scalable electrode systems for electrochemical ammonia recovery. Thirdly, we comparatively analyze the ammonia recovery performance at both the electrode-material and electrode-system levels, comprehensively discussing the current challenges and future research opportunities toward technological scale-up. Finally, we outline key research targets toward next-generation electrochemical engineering for sustainable ammonia recovery and wastewater treatment.

The biochar prepared from biomass by carbonization has been widely used due to the developed pore structure and chemically active surface. In this study, one carbonization method of rice husk via self-sustaining oxygen- limited counter-current combustion was proposed. Such a combustion process has a dynamic propagating combustion front with a temperature of 632-1023 degrees C, allowing the effective carbonization of rice husk with a removal ratio of volatile matter inside rice husk as high as 98.3 %. For this special combustion process, increasing the oxygen concentration achieves a milder but faster carbonization process, characterized with shorter residence time, lower combustion front temperature and higher biochar yield. Compared to the pyrolyzed biochar prepared by the external heating method, the biochar prepared via this combustion process is of a more developed amorphous structure and more oxygen-containing function groups, making the biochar more easily chemically etched and inspiring more activation reactions. Such biochar is suitable to prepare the mesoporedominated activated carbon, especially at low mass ratios of KOH to char. At the ratio of 4, an optimal activation effect with a specific surface area (SBET) of 2863 m 2 g- 1 and total pore volume (VTOT) of 1.854 cm3 g- 1 is achieved.

Efficient and clean utilization remains a pivotal development focus within the coal industry. Nevertheless, the application of weakly caking coal results in energy loss due to the caking property, thereby leading to a waste of resources. This paper, therefore, concentrates on the caking property, offering insights into the relevant caking mechanism, evaluation indexes, and regulation technologies associated with it. The caking mechanism delineates the transformation process of coal into coke. During pyrolysis, the active component generates the plastic mass in which gas, liquid, and solid phases coexist. With an increase in temperature, the liquid phase is diminished gradually, causing the inert components to bond. Based on the caking mechanism, evaluation indexes such as that characteristic of char residue, the caking index, and the maximal thickness of the plastic layer are proposed. These indexes are used to distinguish the strength of the caking property. However, they frequently exhibit a poor differentiation ability and high subjectivity. Additionally, some technologies have been demonstrated to regulate the caking property. Technologies such as rapid heating treatment and hydrogenation modification increase the amount of plastic mass generated, thereby improving the caking property. Meanwhile, technologies such as mechanical breaking and pre-oxidation reduce the caking property by destroying agglomerates or consuming plastic mass.

Hydrothermal carbonization (HTC) is an effective method for sustainable waste conversion and carbon fixation. The carbon stability of solid-derived hydrochar (HC) is a key factor in determining the quality of HTC. This study enhanced carbon recovery by 8% using three inorganic layered double hydroxides (LDHs) as catalysts. LDH addition significantly altered dissolved organic matter (DOM) components and structures in HC. The increase in double bond equivalents (DBE-O) indicated carbon skeleton unsaturation, suggesting DOM mainly comprises compounds with higher unsaturation and lower oxidation. Machine learning (ML) has found that DBE-O is closely related to HC carbon content and stability. Feature importance and SHAP analysis have improved the interpretability of the model. In this study, LDH catalyzed HTC to alter the composition and structure of DOM, resulting in improved carbon stability. ML further revealed the mechanism of DBE-O modification of DOM, thereby enhancing carbon recovery and fixation.

An innovative circulating fluidized bed (CFB) structure with a multi-section variable-diameter riser was proposed to pyrolyze pulverized coal for tar production in this study. Experimental investigations on pulverized coal pyrolysis were conducted to explore the operational characteristics and pyrolysis product distribution of this specially designed CFB reactor, as well as the interconversion mechanisms among distinct pyrolysis products. Results show that the riser's constricted structure enables the spatially partitional reaction regime: a high-temperature dilute-phase char partial gasification occurs below the constricted section, while a low-temperature dense-phase coal pyrolysis above the constricted section. By adjusting the oxygen concentration and equivalence ratio in gasification zone, the sensible heat and composition of gas-solid heat carrier (GSHC) can be effectively controlled, thereby changing the temperature of the pyrolysis zone. Whether it is the increase of oxygen concentration or the increase of equivalence ratio would lead to the increase of syngas content and the decrease of char content. Under the same pyrolysis temperature, the increase of oxygen concentration in gasification zone led to the increase of pyrolysis tar content. A simple molecular model of pulverized coal was established by the FTIR and Raman analysis to reveal transformation of functional groups. The aromatic ether and carboxylic acid, situating at the periphery of molecular model, served as primary sources of oxygen-containing substances. Aliphatic hydrocarbons underwent condensation reaction around 600 & ring;C, which enhanced the concentration of larger polycyclic aromatic hydrocarbons in pyrolysis tar.