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 pyrolysis of pulverized coal takes only a few hundred milliseconds, and the coal combustion/pyrolysis process produces carbon black quickly. The formation of carbon black particles mainly includes their initial nucleation, growth process, fusion, and polymerization [7]. The coal tar generated by the primary pyrolysis of coal contains a ...
This technology builds upon decades of experience with gasification of coal. Both approaches have the potential advantages of being relatively insensitive to feedstock type, both suffer from production of unwanted byproducts. ... Slow pyrolysis is a conventional pyrolysis process whereby the heating rate is kept slow (approximately oC/s ...
Therefore, proper pyrolysis mechanism model can optimize the copyrolysis process to reflect the actual copyrolysis interactions. This work is aimed to detect the primary volatiles from pyrolysis of lowrank coal and waste plastics using insitu PyTOFMS and to further reveal the interactions between coal and plastics based on the primary ...
(1), where m 0, m t were the initial mass of coal and the mass at a given time during the pyrolysis process, respectively. And m ∞ was the final mass of coal sample when the pyrolysis process was completed. (1) α = m 0m t m 0m ∞. The heating rate β was defined as Eq. (2). (2) β = d T d t
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 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.
The chemical structure of coal consists of various covalent and noncovalent interactions, which is the basis of understanding the coal pyrolysis process. 26 Based on proximate analysis, ultimate analysis and 13 CNMR, Mo Zheng 27 constructed a molecular model of NMH coal and used it for ReaxFFMD simulation of pyrolysis tar product. The ...
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 ...
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 ...
The coal samples were pulverized, grounded and sieved to a particle size of less than 75 μm before storing in a desiccator for use. The property analyses of the coals were shown in Table 1. TGA and TGMS experiments. Pyrolysis of the coals was conducted with a TG (50H, Shimadzu, Japan). In. Characterization of coals
Pyrolysis process. Pyrolysis properties of a coal sample were evaluated using TGA. In this study, all TGA experiments initiated at 30 °C, not 300 °C. This decision was supported and validated through multiple experimental runs, ensuring the mass loss monitoring was as accurate as possible. This study's primary emphasis is on the processes ...
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 ...
Pyrolysis is a thermochemical treatment of any organic (carbon based) product at particular temperatures range in the absence of oxygen. The study of pyrolysis includes the changes in chemical composition and characteristics of physical phase (Buratti et al. 2015).This process includes the decomposition of coal's organic structure and the releases of volatile matter up to 70% weight loss.
Coal pyrolysis has experienced more than one hundred years in modern chemical industry, and it is also the basis process of most coal direct conversion, such as gasification and liquefaction. Investigation on the relationships between coal structural characteristics and reactivity is critical for predicting and evaluating thermal reactions in ...
Depolymerization of coal increases the tar yield in coal pyrolysis and enhances the thermoplasticity of the coal, which makes coal more favorable for producing coke and other valueadded products like graphite electrodes, carbon fiber, aromatic chemicals, etc. In this study, the authors have proposed a novel coal depolymerization method that combines the oxidation reactions by molecular oxygen ...
It can be seen from Fig. 11 that the tar yield is improved after adding Group VIII metal oxide catalyst in the coal pyrolysis process; Cr 2 O 3 /γAl 2 O 3 makes the tar yield the highest at ...
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 ...
the yield of pyrolysis products. Jiang et al. investigated an integrated process of coal pyrolysis with steam reforming of propane (CPSRP) to improve tar yield using Ni/Al2O3 as a reforming catalyst [15]. The results suggested that the CPSRP and the integrated coal pyrolysis with steam reforming of methane (CPSRM) or methane with a few propane
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).
The purpose of this paper was to explore the relationship between the volatilization of arsenic and sulfur during the pyrolysis process. The study covered pyrolysis of three coals with different arsenic and sulfur contents under different temperatures. The mode of occurrence of sulfur and arsenic in coal were determined respectively.
In order to further reveal the thermochemical reaction characteristics in the pyrolysis process, the changes of chemical structures of coal during the coking process from room temperature to 520 °C was studied through insitu FTIR, and the results are shown in Figure 5. There are a lot of aromatic structures in the four coking coals, and the ...
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