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 ...
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 ...
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 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 ...
Abstract. The thermal effects of five coal types' pyrolysis processes at heating rates of 5, 10, 15, 20, and 30 °C/min in the temperature range of 301000 °C were systemically investigated by thermogravimetric differential scanning calorimetry degassing stage S2, the pyrolysis stage S3, and the polycondensation stage S4.
Coal SJC, coal WJG, coal ZJM, and coal HCG were selected to investigate the pyrolysis kinetics of northern Shaanxi coals. TG and DSC experiments of four coals were carried out with a synchronous thermal analyzer at heating rates 5, 10, 15, and 20 C/min, respectively. The pyrolysis characteristics were described by thermogravimetric data, and the kinetic parameters were calculated by Flynn# ...
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 ...
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 ...
The pyrolysis process consists of a very complex set of reactions involving the formation of radicals. The overall decomposition of coal is open to manipulation by a variety of experimental conditions. Due to the nature of the coal conversion processes distinction should be made between slow Cheating rate < 1 K/s) and rapid Cheating rate > 1000 ...
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 ...
Therefore, FTIR spectroscopy was employed to analyze the gas generated during the pyrolysis of coal under anaerobic conditions, and the corresponding results are shown in Figures 4(a)4(f). For all samples, the main gases produced during the pyrolysis process were CH 4, CO 2, and water vapor. This result is consistent with the results of the ...
(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
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 ...
Thermocatalytic pyrolysis of waste packaging plastic was investigated in a semi batch reactor. Spent aluminum hydroxide nanoparticle derived from the electrocoagulation of arsenic and fluoride containing synthetic ground water was developed into catalyst through combined thermal treatment and metal impregnation process. Nickel, iron, zinc, copper, and molybdenum were separately doped on the ...
However, in terms of process economy, the required capital cost for highpressure equipment in the liquefaction process makes it less attractive for the industries and persuades them to develop fast pyrolysis for biooil production [6, 128, 136, 137, 142, 143]. It is worth mentioning that the biooil per se is a low value energy carrier.
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 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 ...
During the pyrolysis process, the LHG coal has constantly broken out tars, gases and other key products, accompanied by a large number of free radicals and intermediates produced. The main sources ...
The pyrolysis process of low rank coal is the initial reaction of reductant source in the coalbased reduction process, and the volatiles of the gas pyrolysis product such as H 2 has a significant effect on the subsequent reduction process of iron oxides, which is an ideal reductant for reduction of iron ore.
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.
Pyrolysis polygeneration technology is a good way to realize clean and efficient utilization of lowrank coal and heat carrier is a key factor. Aspen Plus is used to establish lowrank coal pyrolysis staged conversion polygeneration technology with semicoke heat carrier based on dualfluidized bed (CPSCPCDFB), which couples with ultrasupercritical semicoke powder furnace for power generation.
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
Production of synthetic crude oil from coal using the Toscoal pyrolysis process. Conference Cortez, D; LaDelfa, C Proc., Intersoc. Energy Convers. Eng. Conf.; (United States) This paper presents the results of a recent feasibility study of the Toscoal process for recovering oil and gas from coal prior to combustion in power plants. Conceptual ...
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.
The crushed coal particles with the size of 12 mm were selected as feedstock. The results of the proximate analysis and the ultimate analysis of bituminous coal are shown in Table N 2 gas and the simulated fuel gas were used as fluidizing gas. According to previous research results (Ni et al., 2014), the main components of the fuel gas released from the coal pyrolysis in the fluidized ...
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 conventional coal gasification and steam methane reforming processes for hydrogen production are undesirable due to the huge CO 2 emissions. A cleaner technology based on natural gas that has received special attention in recent years is methane pyrolysis. ... Iron and carbon catalysts are therefore the best choice to industrialize the ...
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 ...
During the actual pyrolysis process, the physicochemical structure of coal will be decomposed with the generation of products, such as tar, char, and gaseous compounds [21], [22].Generally, the coal pyrolysis process consists of primary devolatilization reactions and subsequent secondary reactions [23], [24].In this work, to combine the mass transfer with pyrolysis kinetics more conveniently ...
The heterogeneous nature of coal and the complexity of the pyrolysis process have made it very difficult to perform unambiguous experiments to determine the rates and mechanisms in coal pyrolysis. However, recent years have seen a number of new experimental and theoretical approaches which shed new light on the subject. This paper considers the recent progress on kinetics, the formation of ...
The pyrolysis of coal was the process of producing volatiles and coalchar in an inert atmosphere. When the pyrolysis temperature was low, the carbonization of coal particles was dominant, leading the high yield of coalchar. As the temperature further increased, the redecomposition of coalchar generating coalgas occurred, which resulted in ...
The coal pyrolysis is a fundamentally important process since it involves a set of chemical reactions, which play key roles in most coal conversion processes, such as coking, liquefaction, hydrogenation, gasification and combustion. ... Coal softening is a consequence of both physical melting process and pyrolysis breakdown of the coal matrix ...
The copyrolysis process of coal and biomass was simulated using Aspen Plus V11 software. The reliability of the model was verified by comparing the distribution of copyrolysis products under different raw material ratios with the experimental and simulated values. At last, through the economic analysis of the investment in plant construction ...
© DZCrusher - كل الحقوق محفوظة
