Integration of Pyrolysis and Entrained-flow Gasification for Victorian Brown Coal: Experimental and Process Modelling Approaches

The utilization of Victorian brown coal (VBC) is restricted domestically due to its high moisture content and handling difficultly. A stepwise pyrolysis and gasification technology was developed to promote VBC utilization in entrained flow gasifier. The process simulation was conducted using Aspen Plus, where a higher efficiency process was achieved based on exergy analysis. The co-gasification for VBC and bituminous coal has been studied experimentally in terms of reactivity and ash slagging propensity. The completion of this project provides theoretical reference and technical support for VBC industrial gasification applications. It also broadens the utilization range for low-rank fuels in the carbon-constrained future

Process Modeling and Exergy Analysis for a Typical VOC Thermal Conversion Plant

The emission of volatile organic compounds (VOCs) represents a major source of air pollution and presents a major risk to both the surrounding environment and local health. An efficient and clean VOCs conversion process is an important approach for energy conservation and emission reduction. In this work, process simulation is conducted using Aspen Plus according to a VOC thermal oxidizing plant for an industrial-scale aluminum spraying production process. Experimental measurements are used for model validation and the pollutant emissions are consistent with the actual plant operating parameters, where the concentration of sulfur oxides is 32 mg/m³, and that of nitrogen oxides is ~34 mg/m³, both of which are below the requirements specified by the national environment regulations in China. Energy and exergy analyses have been conducted from the perspective of the second law of thermodynamics. It is found that 68.8% of the output energy in the system considered here enters the subsequent oven production line, which will be reused for drying the aluminum plates, and the rest of the energy will contribute to the water heat exchanger; however, the furnace features the largest exergy loss of 34%, and this is due to the high-temperature heat loss. The water heat exchanger features 11.5% exergy loss, which is the largest for the series of heat exchangers, and this loss is due to the large temperature difference between the hot and cold streams in the water heat exchanger. These findings are expected to provide practical approaches to energy conservation from the perspective of energy management

Modeling optimization for a typical VOCs thermal conversion process

Aiming at the current environmental problems, the thermal oxidation treatment for industrial VOCs emission is a common and effective measure. This paper studies on the optimization effect of one optimization method for direct VOCs thermal oxidation of a color aluminum spraying production line based on Aspen-Plus. According to the direct VOCs thermal oxidation process with a 30000 m³/h circulating air volume, propose the flue gas reflux and coating room drainage technology. Use the second law of thermodynamics, and the exergy flow analysis shows the methane consumption could be reduced 12%. Carbon emissions also decreased significantly, with 3.42% reduction. These findings are practical for industrial production cost saving and environmental protection problems solving

XANES Investigation on Sulfur Evolution during Victorian Brown Coal Char Gasification in Oxy-Fuel Combustion Mode

This study has clarified the speciation of sulfur in the pyrolysis char of Victorian brown coal and its evolution during char gasification in oxy-fuel combustion. The synchrotron XANES has been used for sulfur speciation. Coal pyrolysis was first carried out in a lab-scale drop-tube furnace (DTF). The resulting char was then size-segregated and gasified in O₂/N₂ and O₂/CO₂ gases to examine the evolution of sulfur as a function of particle residence time and oxygen fraction in bulk gas. The results indicate that thiophenic sulfur is the predominant form for sulfur in raw coal and its pyrolysis char. The substitution of O₂/CO₂ for O₂/N₂ slightly increased the rate of mass loss of sulfur upon char gasification, due to thermodynamically viable routes for the decomposition of thiophene into COS and CS₂ in CO₂, rather than HS in N₂. For the small char particle rich in highly reactive alkali and alkaline earth metals, the extra loss of sulfur in CO₂ was readily stabilized into sulfate on the local char surface at a relatively long residence time of about 1.6 s in the DTF. The participation of inherent oxygen in char is essential for the sulfation reaction; however, this was inhibited by introducing oxygen into the bulk gas. The rapidly decomposed sulfur present in gaseous oxides preferentially diffused out of the char surface into the bulk gas. The uneven distribution of alkali and alkaline earth metals with respect to char particle size is influential in affecting the sulfation extent on the char surface

Modeling optimization for a typical VOCs thermal conversion process

Aiming at the current environmental problems, the thermal oxidation treatment for industrial VOCs emission is a common and effective measure. This paper studies on the optimization effect of one optimization method for direct VOCs thermal oxidation of a color aluminum spraying production line based on Aspen-Plus. According to the direct VOCs thermal oxidation process with a 30000 m³/h circulating air volume, propose the flue gas reflux and coating room drainage technology. Use the second law of thermodynamics, and the exergy flow analysis shows the methane consumption could be reduced 12%. Carbon emissions also decreased significantly, with 3.42% reduction. These findings are practical for industrial production cost saving and environmental protection problems solving

Evaluation of the Thermal Behavior, Synergistic Catalysis, and Pollutant Emissions during the Co-Combustion of Sewage Sludge and Coal Gasification Fine Slag Residual Carbon

The conversion of solid waste into energy through combustion is sustainable and economical. This study aims to comprehensively evaluate and quantify the co-combustion characteristics, synergistic catalysis, and gaseous pollutant emission patterns of sewage sludge (SS) and coal gasification fine slag residual carbon (RC) as well as their blends through thermogravimetry coupled with mass spectrometry (TG-MS). The results showed that the co-combustion of SS and RC can not only improve the ignition and burnout property but also maintain the combustion stability and comprehensive combustion performance at a better level. The kinetic analysis results showed that a first-order chemical reaction and three-dimensional diffusion are the reaction mechanisms during the co-combustion of SS and RC. The synergistic catalysis between SS and RC can well explain the changes in activation energy and reaction mechanism. Furthermore, the blending ratio of SS is recommended to be maintained at 40% because of the lowest activation energy (Ea = 81.6 kJ/mol) and the strongest synergistic effect (Xi = 0.36). The emission of gaseous pollutants is corresponding to the primary combustion stages of SS, RC, and their blends. In co-combustion, the NH3, HCN, NOx, and SO2 emissions gradually rise with the increase of SS proportion in the blends due to the high content of organic compounds in SS

Functional Carbon from Nature: Biomass‐Derived Carbon Materials and the Recent Progress of Their Applications

Abstract Biomass is considered as a promising source to fabricate functional carbon materials for its sustainability, low cost, and high carbon content. Biomass‐derived‐carbon materials (BCMs) have been a thriving research field. Novel structures, diverse synthesis methods, and versatile applications of BCMs have been reported. However, there has been no recent review of the numerous studies of different aspects of BCMs‐related research. Therefore, this paper presents a comprehensive review that summarizes the progress of BCMs related research. Herein, typical types of biomass used to prepare BCMs are introduced. Variable structures of BCMs are summarized as the performance and properties of BCMs are closely related to their structures. Representative synthesis strategies, including both their merits and drawbacks are reviewed comprehensively. Moreover, the influence of synthetic conditions on the structure of as‐prepared carbon products is discussed, providing important information for the rational design of the fabrication process of BCMs. Recent progress in versatile applications of BCMs based on their morphologies and physicochemical properties is reported. Finally, the remaining challenges of BCMs, are highlighted. Overall, this review provides a valuable overview of current knowledge and recent progress of BCMs, and it outlines directions for future research development of BCMs