N 2 is an important nitrogencontaining product in the process of coal pyrolysis, and understanding its formation mechanism is crucial to control NO x emissions in coal combustion. In this paper, the pyrrolepyridine dinitrogen structure and dipyridine nitrogen structure were selected as the carbonaceous surfaces to investigate effect of different nitrogen forms on N 2 production.
Pyrolysis, which is the initial stage of the coal conversion process, is a significant approach to realize efficient coal resource utilization. Current research on the mechanism of the coal pyrolysis reaction primarily focuses on aspects such as the generation law of pyrolysis products [6], evolution characteristics of the chemical structure [7 ...
The generating rule of H 2 O(g) in coal oxidation and pyrolysis process was similar, probably due to evaporation. All of the output of gas production led to coal mass loss, and CO 2 gas played an important role. Accordingly, we inferred that the intensity of composite reaction between coal and oxygen was stronger than a chemical reaction could ...
Mild gasification of coal is a coal pyrolysis process of low severity compared to other types of coal conversion like gasification, direct liquefaction, or hydropyrolysis. Continuous mild gasification takes place at nearambient pressure and at temperatures of 540° to 760°C. These conditions are designed to maximize the yield of valuable ...
Due to the complexity of coal pyrolysis, there is a challenge to disclose the reaction mechanism of pyrolyzate. So far, the molecular dynamics (MD) based on reactive force field (ReaxFF) is an effective method to study the reactive mechanism of complex compound, and has been widely used in coal pyrolysis process [20].
The coalbased pyrolysis process faces so many challenges based on the production and consumption and also the limited resources, low efficiency and higher emissions. Biological origin. There has been a lot of studies on the feedstocks of biological origin used in microwave pyrolysis. Biological origin here refers to the feedstock having a ...
The whole treatment process of CPW is shown in Fig. 1. The coal particles are introduced into the drying unit to provide steam for CLG and the remaining dry coal enters into the pyrolysis unit to produce pyrolysis gas and char. The CPW is generated during cooling and separation of pyrolysis gas. The dotted red line represents the impact of CPW ...
In this study, coal fly ash was functionalized, using a simple onestep process (loading with Al3+ and sulfonation), to yield a solid acid catalyst (S/AlCFA) with strong acid sites. The catalyst was then used to produce furfural from xylose in a biphasic system (H2O(NaCl)/tetrahydrofuran). The furfural yield reached 82% at 180 °C60 min with catalyst/xylose ratio of : (w/w).
For the coal pyrolysis process, unstable sulfur compounds will decompose, generate sulfur radicals and release as sulfurcontaining gases, this becomes the main pathway for sulfur removal. Coal properties, minerals and sulfur forms in coal, and pyrolysis conditions such as temperature, atmosphere, and the mass transfer, are the main factors ...
The pyrolysis characteristics of Shenmu coal under an atmosphere containing H2 (40%) and another containing CH4 (40%) were studied via a thermogravimetric analysis, and the kinetic parameters of pyrolysis were calculated by using a distributed activation energy model (DAEM). The results showed that H2 promoted the cleavage of CHlike functional groups by providing reactive hydrogen groups to ...
The breaking of chemical bonds is the fundamental process in pyrolysis. Coal pyrolysis is the first step in coal gasification and other chemical processes, and is the basic process in clean coal technologies. Coal pyrolysis is closely related to coal composition and structure. The molecular structure of coal can be clarified based on pyrolysis ...
When the temperature exceeds 3250 K, the pyrolysis reaction was completed and the yield of each product stabilizes. The lower heating rate completely reproduces the pyrolysis process of coal, and the pyrolysis stages obtained by simulation are close to Fugu subbituminous coal [57]. At 10 K/ps, the content of char is the least and Ltar is the ...
INTRODUCTION. Pyrolysis is the key process in carbon nanomaterial synthesis [], bulk carbon production [5, 6], fabrication of carbonbased devices [], fuel generation from organic waste [] and molecule fragmentation for their analysis via gas chromatographymass spectroscopy (GCMS) [].Primary examples of the technologically significant carbon materials prepared via pyrolysis include ...
A multiphysics numerical method coupling fluid flow, heat transfer, and a chemical reaction was used to determine the temperature distribution and the conversion rate of a coal seam during underground pyrolysis. The coal seam was fractured to enhance the heat and mass transfer. The influences of the pyrolysis pressure on the heat transfer, oil and gas production, and pyrolysis time were also ...
Coal pyrolysis is a critical step of coal thermal conversion, impacting the downstream utilisation of coal, such as combustion and gasification. The understanding of this complex process plays a crucial role to predict the products, operation optimisation and reactor design. Indian coals typically have 2552% (as received) ash yields.
The scientific and industrial community's interest in the pyrolysis process has increased significantly over the past few decades. The amount of scientific documents published on pyrolysis using either coal or biomass as feedstock for different years is shown in Fig. can be observed that research in both coal and biomass pyrolysis processes has increased significantly since the 1960s.
As a comprehensive description of the functional groups effect on various volatile products during coal pyrolysis process, it is found that both alkyl and oxygencontaining groups can reduce the BDEs of the bridge bonds between aromatic rings during pyrolysis process, and the effect of oxygencontaining groups is more obvious. ...
The complexity of coal combustion has made more researchers divide the combustion process into two stages: pyrolysis and late combustion. Up to now, many studies have been done on transformation behavior of nitrogen during coal pyrolysis [16], [17] and occurrence state and content of nitrogen in coal [18] .
The effect of coal rank, heating rate, and temperature on the coal pyrolysis process were discussed in this work. The initial pyrolysis pathways of different ranks of coals have been obtained, and the variation of hydrogen and carbon monoxide yield with temperature was also discussed. Fortunately, we have reached some important conclusions:
The pyrolysis of coal is a good method for producing liquid fuels and other chemicals; however, the yields of these products are limited due to low content of hydrogen in coal. Hydropyrolysis, a pyrolysis process under hydrogen, is an effective method to improve tar yield and quality, but high cost of pure hydrogen hinders its industrial ...
Also, we investigate the catalytic activity of the catalysts in coal pyrolysis process. 2 Methodology and Experiments. Preparation of NiCo Ternary Molten Salt Crystal Catalysts. The molten salt crystal synthesis method has been proposed by Rockwell International Corporation in 1965 . And it is an efficient method for the preparation of ...
Pyrolysis, which is the initial stage of the coal conversion process, is a significant approach to realize efficient coal resource utilization. Current research on the mechanism of the coal pyrolysis reaction primarily focuses on aspects such as the generation law of pyrolysis products [6], evolution characteristics of the chemical structure ...
More importantly, during the pyrolysis process of 3560 mesh coal, the largest amount of coalchar and the smallest amount of coaltar are not only obtained, but highquality syngas is also obtained. Through the characterization of coaltar, it is found that coaltar is mainly composed of aromatic compounds, and the content can reach more ...
Two wellknown products created by pyrolysis are a form of charcoal called biochar, created by heating wood, and coke (which is used as an industrial fuel and a heat shield), created by heating coal. Pyrolysis also produces condensable liquids (or tar) and noncondensable gases. Process
© DZCrusher - كل الحقوق محفوظة
