Effect of the COMBDry Dewatering Process on Combustion Reactivity and Oxygen-Containing Functional Groups of Dried Lignite

Zhao, Yaying,Zhao, Guangbo,Sun, Rui,Liu, Hui,Wang, Zhuozhi,Sihyun, Lee,Kong, Ming American Chemical Society 2017 ENERGY AND FUELS Vol.31 No.4

<P>Two typical types of Chinese lignite samples were employed to investigate the coal drying characteristics of an innovative COMBDry lignite drying system. The drying rate increased significantly with an increase in drying temperature and ratio of the flue gas, to the lignite. Using a nitrogen adsorption instrument, it was found that the drying process promoted generation and enlargement of the surface pore structures of the particles, which can enhance coal combustion rate. A horizontally fixed bed furnace and a SIGNAL S4i pulsar NDIR (infrared (IR)) gas analyzers were used to investigate the combustion characteristics of coal samples after the drying treatment. In an attempt to analyze the variation in the sample surface chemical structure during the drying process, Fourier transform infrared (FT-IR) spectrometry and Raman spectroscopy were employed for the investigation. The results showed that the concentration of aliphatic hydrogen decreased with an increase in drying temperature and resulted from the decomposition of oxygen-containing complexes (released CO and CO2) and reaction with hydroxyl groups. The number of functional groups decreased when the drying temperature exceeded 210 degrees C. The amount of carbonyl and carboxylic esters initially increased and then (210 degrees C) decreased with an increase in flue gas temperature, and the content of aromatic carbon was unchanged with the treatment. The ordered crystalline carbon changed into the crystal defect structure and amorphous carbon and the degree of graphitization decreased and thus the combustion reactivity of the dried lignite was improved.</P>

Promotional effects of Sm2O3 on Mn-H4SiW12O40/SiO2 catalyst for dimethyl ether direct-oxidation to dimethoxymethane

Qingde Zhang,Yizhuo Han,Yisheng Tan,Guangbo Liu,Caihong Yang 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

The promotional effects of Sm2O3 on Mn-H4SiW12O40/SiO2 for dimethyl ether (DME) direct-oxidation to dimethoxymethane (DMM) were investigated. The results showed that Sm2O3 introduction could significantly improve the activity of Mn-H4SiW12O40/SiO2 for DMM formation, and DMM selectivity was remarkably increased from 36.3% to 60.3% when the Sm2O3 content was 1%. The catalysts were characterized by ICP-AES, XRD, NH3-TPD, Pyridine-IR and XPS. The Sm2O3 introduction enhanced the number of Lewis acid sites and weak acid sites and also increased the amount of Mn4+ species of Mn-H4SiW12O40/SiO2, which is favorable for the formation of DMM.

Oxidation of Zhundong subbituminous coal by Fe2+/H2O2 system under mild conditions

Shuai Chen,Wei Zhou,Mingjun Liu,Guangbo Zhao,Qingxi Cao,Bojun Zhao,Kaikai Kou,Jihui Gao 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.4

Oxidation of coal under mild conditions is effective not only to understand the macromolecular network structure of coal but also to produce useful chemicals, allowing more efficient application of coal resources. In this work, the mild oxidation of Zhundong subbituminous coal (ZS) by Fe2+/H2O2 system was carried out under various conditions, including [Fe2+]/[H2O2] molar ratio, temperature, H2O2 concentration and oxidation time. The liquid oxidation products were analyzed using gas chromatography/mass spectrometry (GC/MS), and the chemical structure changes were studied using Fourier transform infrared spectroscopy (FTIR). The results suggest that the oxidation efficiency of ZS with H2O2 is enhanced with the aid of Fe2+. The optimum conditions were determined to be [Fe2+]/[H2O2] molar ratio of 0.00453, H2O2 concentration of 3mol/L, 60 oC and 4 h according to the oxidation conversion rate. In total, 25 compounds were identified, which could be categorized as six group components. Most of them are valuedadded chemicals, and the content of benzene carboxylic acids is the highest among them, making up 29.99% of all group components in total relative content (TRC). -CH2- should be primary bridge connecting the aromatic rings, and alkylene chains linking three aromatic rings are abundant in ZS.

An S-scheme photocatalyst constructed by modifying Ni-doped Sn3O4 micro-flowers on g-C3N4 nanosheets for enhanced visible-light-driven hydrogen evolution

Dandan Wang,Zhaoxin Lin,Chun Miao,Wei Jiang,Hongji Li,Chunbo Liu,Guangbo Che 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-

Carbon nitrides (g-C3N4) is considered to be the prospective semiconductor photocatalyst for photocatalytic H2 evolution. Nevertheless, it suffers from low charge transfer efficiency and fewer metal active sites. Thereby, Ni-Sn3O4/g-C3N4 photocatalysts were constructed by anchoring Ni-doped Sn3O4 micro-flowers on g-C3N4 via a feasible and straightforward solvothermal treatment. The prepared Ni-Sn3O4/g-C3N4 S-scheme heterojunction could improve the transfer and separation efficiency of photo-generated electron-hole pairs by facilitating the electrons transfer from Ni-Sn3O4 to g-C3N4. Moreover, the photocatalytic H2 production performance was ameliorated due to the established internal electric field and the energy band bending in Ni-Sn3O4/g-C3N4 S-scheme heterojunction. Meanwhile, the doping Ni in Sn3O4 exposed more active sites in Ni-Sn3O4/g-C3N4 heterojunction for producing H2. As a result, Ni-Sn3O4/g-C3N4-5 photocatalyst exhibited outstanding H2 yields of 1961 µmol h−1 g−1 under visible light irradiation in comparison with pure Ni-Sn3O4 (12 µmol h−1 g−1) and bared g-C3N4 (1391 µmol h−1 g−1). Furthermore, the S-scheme mechanism in Ni-Sn3O4/g-C3N4 heterojunction for producing H2 by oxidizing H2O was proposed. This study provides helpful guide for developing efficient g-C3N4-based photocatalytic systems.

Accuracy modeling, analysis and radical error distribution of 3-RPR planar parallel mechanism

Jian Ding,Changlong Ye,Suyang Yu,Jianguang Li,Jinguo Liu,Guangbo Hao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.11

Output accuracy performance is directly determined by geometric errors and working poses of a mechanism. Accuracy sensitivity as geometric error transmission coefficient, closely relates to pose configuration and geometric parameters. This research focuses on accuracy of a 3-RPR planar parallel mechanism: firstly, established 3 models in an analytic form, to describe relationship between output errors and geometric ones, then they are mutually verified statistically. Secondly, the anisotropy and periodic fluctuation of position errors, independently contributed by each category of geometric errors, are illustrated; and mirror symmetric trajectories and poses generating output errors with mirror symmetry, are also revealed by numerical simulation. Finally, the radical accuracy model in an analytic form, was established through variance and covariance analysis on output errors. We concluded that the radical error of the movable platform in central symmetric poses, follows Rayleigh distribution pattern. Through statistical comparison with Monte Carlo simulation, the radical error model was demonstrated, that provided a reference for accuracy design for other planar parallel mechanism.

Ion-imprinted antifouling nanocomposite membrane for separation of lithium ion

Dongshu Sun,Tianyu Zhou,Yang Lu,Yongsheng Yan,Chunbo Liu,Guangbo Che 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.9

Membrane fouling is a primary challenge restricting the practical application of membrane separation technology. Inspired by the idea that improving hydrophilicity would lead to antifouling performance of membrane material. In this work, ion-imprinted antifouling nanocomposite membrane (LiI-NcMs) blended with GO and TiO2 nanomaterialwas fabricated for selective separation of lithium ion. As a result, markedly improved hydrophilicity was achievedon LiI-NcMs (55.1o for contact angle). LiI-NcMs also showed good selective adsorption capacity in the mixed solutionof Mg2+ and Li+. Moreover, LiI-NcMs exhibited superior stability; after 20 adsorption/desorption cycles a maximumadsorption capacity of 88.1% can be maintained. This work demonstrates a new and facile approach to prepare novelmembrane separation material for a particular substance for efficient selective separation in industrial applications.