The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Thomas H. Fletcher - One of the best experts on this subject based on the ideXlab platform.
-
Effects of Pressure on Coal Pyrolysis and Char Morphology
Energy & Fuels, 2005Co-Authors: Dong Zeng, Thomas H. FletcherAbstract:A better understanding of high-pressure Coal Pyrolysis is needed to design advanced Coal gasification combined-cycle systems. High-temperature, high-heating-rate, and high-pressure Pyrolysis experi...
-
Simulation of Coal Pyrolysis in Plasma Jet by CPD Model
Energy & Fuels, 2001Co-Authors: Tian Yajun, Kechang Xie, Suyu Zhu, Thomas H. FletcherAbstract:Reaction of Coal in a plasma jet is complex and extremely rapid, and acetylene and carbon monoxide are the main products in the Pyrolysis gas. Coal Pyrolysis is assumed as the first step reaction when Coal is injected into hot plasma jet with initial average temperature of 3700 K. Chemical percolation devolatilization (CPD) is employed first to simulate this procedure in mechanism. The calculation results indicate Coal Pyrolysis rate in plasma jet is very fast and the retention time of Coal staying in reactor is only several milliseconds. Comparing the calculation with experiment result, it was concluded that the CPD agree with the experiment well when the Coal feed rate is larger than about 2.0 g s-1. As the Coal feed rate was increased, the average temperature of Coal particle during staying in reactor was reduced and the residual time became long, but it was not found that the residual time influenced the Coal conversion evidently.
Lijun Jin - One of the best experts on this subject based on the ideXlab platform.
-
Oxidative Catalytic Cracking and Reforming of Coal Pyrolysis Volatiles over NiO
Energy & Fuels, 2020Co-Authors: Dechao Wang, Lijun Jin, Baoyong WeiAbstract:Catalytic cracking of Pingshuo (PS) Coal Pyrolysis volatiles was investigated over NiO on a two-stage fixed bed reactor. The effect of the NiO loading amount and catalytic upgrading temperature on ...
-
Integrated Coal Pyrolysis with steam reforming of propane to improve tar yield
Journal of Analytical and Applied Pyrolysis, 2020Co-Authors: Huixiu Jiang, Mingyi Wang, Lijun JinAbstract:Abstract An integrated process of Coal Pyrolysis with steam reforming of propane (CP-SRP) to improve tar yield was studied using Ni/Al2O3 as reforming catalyst. Comparing with Coal Pyrolysis under N2 atmosphere (CP-N2), the CP-SRP and the integrated Coal Pyrolysis with steam reforming of methane (CP-SRM) or methane with a few propane (CP-SRMP) show higher tar yield. Tar yield reaches its maximum at 600 °C in CP-SRP, which is 1.17, 1.14, and 1.11 times that in CP-N2, CP-SRMP and CP-SRM, respectively. Simulated distillation and GC–MS were used to characterize the fraction distributions and compositions of tar, which indicated the tar from CP-SRP has higher light oil, phenols and naphthalenes content than that from CP-N2. Isotopic tracer agents like C3D8 and D2O were used to study the tar formation mechanism in CP-SRP. The radicals like D, CD3 generated by activated C3D8 and D2O in SRP combine with radicals formed from Coal Pyrolysis to improve tar yield and change the product distribution.
-
Integrated process of Coal Pyrolysis with CO2 reforming of methane by spark discharge plasma
Journal of Analytical and Applied Pyrolysis, 2017Co-Authors: Lijun Jin, Yongqiang Feng, Aimin ZhuAbstract:Abstract An integrated process of Coal Pyrolysis with CO 2 reforming of methane by spark discharge plasma was developed to improve the tar yield of Coal Pyrolysis. The effects of the reactor configuration parameters and the integrated process conditions were investigated. It was found that the conversions of CH 4 and CO 2 and the selectivies of H 2 and CO increase with the discharge input power. The electrode with a large- diameter and long discharge gap are unbeneficial to conversion of CO 2 and CH 4 . The reaction temperature has little effect on the conversion of reaction gases. In the integrated process, the tar and water yields increase with the Pyrolysis temperature and holding time. The Pyrolysis atmosphere remarkably influences the tar yield. Compared with the Pyrolysis under N 2 (Py-N 2 ) or the mixture gas of CO 2 and CH 4 (Py-MG), the integrated process of CO 2 reforming of CH 4 with Coal Pyrolysis can produce more tar, which is ascribed to the interaction of activated CH 4 by spark discharge plasma with the free radicals from Coal Pyrolysis. The tar yield is 1.4 times as Py-MG, and 1.5 times as Py-N 2 at the Pyrolysis temperature of 550 °C.
-
Integrated process of Coal Pyrolysis and CO2 reforming of methane with and without using dielectric barrier discharge plasma
Energy Sources Part A: Recovery Utilization and Environmental Effects, 2016Co-Authors: Lijun Jin, Wei HuaAbstract:ABSTRACTThe integrated processes of Shenmu subbituminous Coal Pyrolysis and CO2 reforming of methane over catalyst (Ni/SiO2) with and without using dielectric barrier discharge plasma (ICCP and ICCC) were carried out to check the effectiveness of the integrated process on improving the tar yield of Coal Pyrolysis. The effects of the Pyrolysis temperature and time on product yields were investigated. The results indicate that both the ICCC and ICCP have an effect on increasing the tar yield compared with Coal Pyrolysis under N2 or H2. The tar yield increases with the increase of Pyrolysis temperature and time in the ICCC, while relatively lower Pyrolysis temperature and shorter Pyrolysis time is preferable in the ICCP. The highest tar yield is 24.8 wt% at 600°C for 22 min in the ICCC and that is 23.7 wt% at 500°C for 7 min in the ICCP.
Kechang Xie - One of the best experts on this subject based on the ideXlab platform.
-
Release behavior and formation mechanism of polycyclic aromatic hydrocarbons during Coal Pyrolysis.
Chemosphere, 2016Co-Authors: Meiqi Gao, Jie Dong, Yulong Wang, Kechang XieAbstract:Abstract Polycyclic aromatic hydrocarbons (PAHs) are major environmental pollutants. They have attracted considerable attention due to their severe potential carcinogenic, mutagenic and genotoxic effects on human health. In this study, five different rank Coals from China were pyrolyzed using pyro-probe CDS 5250 and the release behavior of 16 PAHs under different Pyrolysis conditions were studied by Gas Chromatography-Mass Spectrometer (GC-MS). The structural characteristics of the five Coals were determined by Cross-Polarization/Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS 13 C NMR) spectroscopy, and then the factors influencing the formation of PAHs during Coal Pyrolysis were discussed together with the Coal structural data. It was shown that the amount of PAHs generated during Coal Pyrolysis was largely related to Coal rank and followed the order of medium metamorphic Coal > low metamorphic Coal > high metamorphic Coal. The amount of total PAHs varied as the temperature was increased from 400 °C to 1200 °C, which showed a trend of first increasing and then decreasing, with the maximum value at 800 °C. Moreover, the species of PAHs released varied with Pyrolysis temperatures. When the temperature was lower than 800 °C, the small ring PAHs were the most abundant, while the proportion of heavy rings increased at higher temperature. The results indicate that the formation of PAHs during Coal Pyrolysis depends on the structure of the Coal. The species and amounts of PAHs generated during Coal Pyrolysis are closely related to the contents of protonated aromatic carbons and bridging ring junction aromatic carbons present in the Coal structure.
-
Simulation of Coal Pyrolysis in Plasma Jet by CPD Model
Energy & Fuels, 2001Co-Authors: Tian Yajun, Kechang Xie, Suyu Zhu, Thomas H. FletcherAbstract:Reaction of Coal in a plasma jet is complex and extremely rapid, and acetylene and carbon monoxide are the main products in the Pyrolysis gas. Coal Pyrolysis is assumed as the first step reaction when Coal is injected into hot plasma jet with initial average temperature of 3700 K. Chemical percolation devolatilization (CPD) is employed first to simulate this procedure in mechanism. The calculation results indicate Coal Pyrolysis rate in plasma jet is very fast and the retention time of Coal staying in reactor is only several milliseconds. Comparing the calculation with experiment result, it was concluded that the CPD agree with the experiment well when the Coal feed rate is larger than about 2.0 g s-1. As the Coal feed rate was increased, the average temperature of Coal particle during staying in reactor was reduced and the residual time became long, but it was not found that the residual time influenced the Coal conversion evidently.
Jie Feng - One of the best experts on this subject based on the ideXlab platform.
-
Evaluation on a combined model for low-rank Coal Pyrolysis
Energy, 2019Co-Authors: Jie FengAbstract:Abstract Pyrolysis is an initial step of the upgrading lignite that exhibits a structurally complex connection between physicochemical changes and unknown pyrolyzed compounds, which complicates process simulation for downstream processing. Combined the functional group-depolymerization vaporization cross-linking (FG-DVC) model with non-linear programming (NLP) theory would link between Coal Pyrolysis and process simulation. First, we adjust the range of the van Krevelen diagram and predict the char and volatiles yields from Coal Pyrolysis using the FG-DVC model. The tar ultimate analysis is then estimated based on mass/element conservation, and the tar group composition is calculated using the NLP model on the basis of the total tar yield and ultimate analysis. Upon completion of these steps, the process simulation and energy consumption distribution of Coal Pyrolysis is carried out using Aspen Plus. Results show that the FG-DVC model with the adjusted van Krevelen diagram can accurately predict Coal Pyrolysis products with better performance than that obtained using empirical correlations. Results show that the energy consumption of drying Coal was the largest with 653.2 MJ when drying 1000 kg of Coal, followed by Pyrolysis with 482.2 MJ. The combined Coal Pyrolysis model, being independent on experiments, can be used for process design.
-
The interaction between the char solid heat carrier and the volatiles during low-rank Coal Pyrolysis
Journal of Analytical and Applied Pyrolysis, 2018Co-Authors: Jie FengAbstract:Abstract Compared with traditional Coal Pyrolysis technology, low-rank Coal Pyrolysis with char as the solid heat carrier can achieve higher tar yield and lighter tar components. The hot char provides heat for Coal Pyrolysis process and has a thermal catalytic effect on the reactions of released volatiles. Simultaneously, the physicochemical properties and reactivity of the hot char have changed. The effects of the initial temperature of the solid heat carrier on the products of a low-rank Coal Pyrolysis and on the change of the solid heat carrier after Pyrolysis were investigated in a downer reactor. With the initial temperature of the char solid heat carrier increasing from 650 °C to 800 °C, the reactions between volatiles and the hot char solid heat carrier were different, which resulted in the variations in the final product distributions and tar composition. The char solid heat carrier exhibited the best catalytic cracking effect at 800 °C on volatiles generated during Coal Pyrolysis. The inorganic minerals in Coal may play an important catalytic role in the subsequent Coal-char-CO2 gasification after the Coal Pyrolysis.
Chen-lin Chou - One of the best experts on this subject based on the ideXlab platform.
-
Behavior of sulfur during Coal Pyrolysis
Journal of Analytical and Applied Pyrolysis, 1994Co-Authors: Dakang Shao, Erik J. Hutchinson, Jenny L. Heidbrink, Wei-ping Pan, Chen-lin ChouAbstract:Abstract The behavior of sulfur in Illinois Coals during Pyrolysis was evaluated by thermogravimetry/ Fourier transform-infrared spectroscopy (TG/FT-IR) techniques. SO2, COS, and H2S were major gaseous sulfur-containing products observed during Coal Pyrolysis. The release rates of the gaseous sulfur species showed several peaks within the temperature ranges, which were due to the emission of different forms of sulfur in Coal.