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Yulong Zhang,Sheng Xue,Junfeng Wang,Yue Wu,Zhengfeng Li,Liping Chang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.3
−It is imperative to have an in-depth understanding of the intrinsic reaction between coal and oxygen during low-temperature oxidation, as the reaction is the main source responsible for the self-heating and spontaneous combustion of coal. As low-temperature oxidation of coal involves a series of physical and chemical process and many parallel reactions, it is difficult to directly investigate the intrinsic reaction between coal and oxygen by conventional analytical method. Thermogravimetric analysis (TGA) was used to investigate the intrinsic reaction between coal and oxygen based on the mass change. By means of the subtraction analysis method of TGA, the TG-subtraction curves were obtained by subtracting the TG-N2 curves from the TG-air curves. The results indicate that a TG-subtraction curve can better reflect the intrinsic reaction of coal oxidation than a TG-air curve by eliminating the influence of evaporation of water and thermal decomposition of inherent oxygen-containing groups. In terms of the rate of mass increase, the intrinsic reactions can be divided into three stages: slow oxidation stage, advanced oxidation stage and rapid oxidation stage. The activation energy at each of the stages, obtained by Coats and Redfern’s model, can be used to as a technical parameter to evaluate the proneness of coal spontaneous combustion. The optimum experiment conditions were also developed to study low-temperature coal oxidation with the subtraction method of TGA.
Simultaneous SAXS-WAXS study on coking coal during high temperature carbonization
Wang Yuexiang,Li Zhihong,Kong Jiao,Chang Liping 한국탄소학회 2023 Carbon Letters Vol.33 No.2
Coking coal is an important raw material for coke production. In this study, in an inert atmosphere, two Chinese coking coal samples were, respectively, heated gradually to 1200 °C to release volatile and form char and coke in succession, then cooled naturally to close room temperature to age the coke. The whole heating and cooling process on carbonization were monitored in situ by simultaneous small and wide-angle X-ray scattering (SAXS-WAXS) technique based on a synchrotron radiation platform. The simultaneous structural changes of pore and skeleton in coal during carbonization are revealed for the first time. The two raw coal samples, with similar carbon content and slightly different coalification degree, undergone a carbonization process similar in whole and different in parts. The carbonization presents approximately three stages during heating process and one stage during cooling process. The coal structure changes wavily during heating and monotonously during cooling. The corresponding structural change mechanism is analyzed.
Lo, Li,Belt, Simon T.,Lattaud, Julie,Friedrich, Tobias,Zeeden, Christian,Schouten, Stefan,Smik, Lukas,Timmermann, Axel,Cabedo-Sanz, Patricia,Huang, Jyh-Jaan,Zhou, Liping,Ou, Tsong-Hua,Chang, Yuan-Pin Elsevier 2018 Earth and planetary science letters Vol.488 No.-
<P><B>Abstract</B></P> <P>Recent reduction in high-latitude sea ice extent demonstrates that sea ice is highly sensitive to external and internal radiative forcings. In order to better understand sea ice system responses to external orbital forcing and internal oscillations on orbital timescales, here we reconstruct changes in sea ice extent and summer sea surface temperature (SSST) over the past 130,000 yrs in the central Okhotsk Sea. We applied novel organic geochemical proxies of sea ice (IP<SUB>25</SUB>), SSST ( TEX L 86 ) and open water marine productivity (a tri-unsaturated highly branched isoprenoid and biogenic opal) to marine sediment core MD01-2414 (53°11.77′N, 149°34.80′E, water depth 1123 m). To complement the proxy data, we also carried out transient Earth system model simulations and sensitivity tests to identify contributions of different climatic forcing factors. Our results show that the central Okhotsk Sea was ice-free during Marine Isotope Stage (MIS) 5e and the early-mid Holocene, but experienced variable sea ice cover during MIS 2–4, consistent with intervals of relatively high and low SSST, respectively. Our data also show that the sea ice extent was governed by precession-dominated insolation changes during intervals of atmospheric CO<SUB>2</SUB> concentrations ranging from 190 to 260 ppm. However, the proxy record and the model simulation data show that the central Okhotsk Sea was near ice-free regardless of insolation forcing throughout the penultimate interglacial, and during the Holocene, when atmospheric CO<SUB>2</SUB> was above ∼260 ppm. Past sea ice conditions in the central Okhotsk Sea were therefore strongly modulated by both orbital-driven insolation and CO<SUB>2</SUB>-induced radiative forcing during the past glacial/interglacial cycle.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The first orbital timescale proxy-model sea ice-sea surface temperature records from the northwestern subarctic Pacific Ocean. </LI> <LI> Strong precession forcing controlled and sea ice variations are modulated by greenhouse gas radiative forcing. </LI> <LI> Sea ice remained free in the central Okhotsk Sea during MIS 5e due to high greenhouse gas radiative forcing. </LI> </UL> </P>
Jianglong Yu,Liping Chang,Wei Xie,Dehai Wang 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.4
Thermodynamic analysis of the correlation of H_2S and COS has been carried out at the temperature range of 400-650 ℃ at which high temperature desulfurization of coal gas is usually performed. The correlation of the two sulfur species is mainly through the reaction H_2S+CO→COS+H_2. Simulated coal gas with the following composition CO 32.69%, H_2 39.58%, CO_2 18.27%, N2 8.92% and H_2S 0.47% was used in this study, and the equilibrium concentrations of the two species at different temperatures were calculated. The results of Fe-based sorbents during sulfidation were compared with calculations. It is concluded that the above reaction may reach equilibrium concentration in the presence of the Fe-based sorbents, which means the Fe-based sorbents may effectively catalyze the reaction between H_2S and CO. Because of the correlation of the two sulfur species, both can be effectively removed at high temperatures simultaneously, offering high temperature desulfurization some advantages over low temperature desulfurization processes.
Xiaogang Zheng,Liping Wang,Yuanliang Zhou,Meiyin Luo,Hongyan Li,Zongyang Bo,Weixin Zheng,Chenggong Chang,Jing Wen,Jinmei Dong 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-
Biochar-based composites have been intensively applied in wastewater treatment. To boost theadsorption-photocatalytic capacity of biochar for dyes elimination, S-doped biochar was commodifiedby NiS and MgO (NiS-Mg/S-BC) via the one-pot sulfurization at high temperature. The functional groupsin NiS-Mg/S-BC provided the abundant vacant sites for RhB adsorption and photocatalysis, and the junctioninterface among NiS, MgO, and S-doped biochar was likely to form the channels for the separationand transfer of photo-induced e-/h+ pairs. NiS-Mg/S-BC presented the better adsorption-photocatalyticcapacity of RhB than S-doped biochar, NiS and MgO modified biochar. Langmuir and second-order modelswell described the adsorption behaviors of NiS-Mg/S-BC. The removal efficiency of optimal 2b-NiS-Mg/SBCfor 400 mg/L RhB solution was 96.98% within 120 min, and its adsorption capacity based on secondordermodel was 802.49 mg g1. The photo-corrosion induced to the declined removal efficiency of 2b-NiS-Mg/S-BC to 94.13% after five cycles.
Ziyan Ren,Siying He,Liping Zhang,Yanli Qi,Chang Seop Koh 한국자기학회 2020 Journal of Magnetics Vol.25 No.3
Recently, many design problems in the field of electrical engineering tend to be more complex, which are characterized by large scale in size, strong nonlinearity for performance analysis, and multi-dimensional design parameters. Therefore, it is not easy to seek for optimum effectively by traditional optimization algorithms. In order to solve optimal design of complex practical problems, in this paper, a novel hybrid optimization algorithm based on the differential evolution algorithm and the black hole theory is proposed and investigated. The differential evolution (DE) algorithm owns good diversity and flexibility, while the black-hole based optimization algorithm (BHBO) possesses faster convergence. In addition, these two algorithms have simple structures. The proposed algorithm with better merits combination may guarantee better convergence and stronger robustness than its independent counterparts of DE and BHBO. The searching performance is deeply investigated through numerical experiments on benchmark functions and practical electromagnetic applications.
Composite action of hollow concrete-filled circular steel tubular stub columns
QIANG FU,Fa-Xing Ding,Tao Zhang,Liping Wang,Chang-jing Fang 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.6
To better understand the influence of hollow ratio on the hollow concrete-filled circular steel tubular (H-CFT) stub columns under axial compression and to propose the design formula of ultimate bearing capacity for H-CFT stub columns, 3D finite element analysis and laboratory experiments were completed to obtain the load-deformation curves and the failure modes of H-CFT stub columns. The changes of the confinement effect between core concrete and steel tube with different hollow ratios were discussed based on the finite element results. The result shows that the axial stress of concrete and hoop stress of steel tube in H-CFT stub columns are decreased with the increase of hollow ratio. After the yield of steel, the reduction rate of longitudinal stress and the increase rate of circumferential stress for the steel tube slowed down. The confinement effect from steel tube on concrete also weakened slowly with the increase of hollow ratio. Based on the limit equilibrium method, a simplified formula of ultimate bearing capacity for the axially loaded H-CFT stub columns was proposed. The predicted results showed satisfactory agreement with the experimental and numerical results.