Evolution of Char Structure During In-Situ Biomass Tar Reforming: Importance of the Coupling Effect Among the Physical-Chemical Structure of Char-Based Catalysts

2020 ◽  
Author(s):  
Dongdong Feng ◽  
Yu Zhang ◽  
Yijun Zhao ◽  
Shaozeng Sun
Keyword(s):  
Chemical Structure ◽  
Coupling Effect ◽  
Physical Chemical ◽  
Biomass Tar ◽  
Char Structure ◽  
Tar Reforming

scholarly journals Evolution of Char Structure During In-Situ Biomass Tar Reforming: Importance of the Coupling Effect Among the Physical-Chemical Structure of Char-Based Catalysts

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 711 ◽  
Author(s):  
Yu Zhang ◽  
Dongdong Feng ◽  
Yijun Zhao ◽  
Heming Dong ◽  
Guozhang Chang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Fluidized Bed ◽  
Chemical Structure ◽  
Coupling Effect ◽  
Coal Char ◽  
Physical Chemical ◽  
Biomass Tar ◽  
Specific Reactivity ◽  
Tar Reforming

In order to illustrate the importance of a coupling effect in the physical-chemical structure of char-based catalysts on in-situ biomass tar reforming, three typical char-based catalysts (graphite, Zhundong coal char, and sawdust biochar) were studied in the fixed-bed/fluidized-bed reactor. The physical-chemical properties of carbon-based catalysts associated with their catalytic abilities were characterized by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), Raman, X-ray photoelectron spectroscopy (XPS), scanning electron microscope–energy dispersive spectrometer (SEM-EDS) and N2 adsorption. The relationship between the specific reactivity and tar reforming ability of carbon-based catalysts was discussed through a micro fluidized bed reaction analyzer (MFBRA–MR). The results indicate that the char-based catalyst has a certain removal ability for in-situ biomass tar of corn straw in an inert atmosphere, which is as follows: sawdust biochar > Zhundong (ZD) coal char > graphite. During the in-situ tar reforming, the alkali and alkaline earth metal species (AAEMs) act as adsorption/reaction sites, affecting the evolution of the aromatic ring structure and oxygen-containing functional groups of the char-based catalyst, and also its pore structure. AAEM species on the surface of char-based catalysts are the active sites for tar reforming, which promotes the increase of active intermediates (C-O bond and C-O-AAEMs), and enhances the interactions between char-based catalysts and biomass tar. The abundant AAEMs may lead to the conversion of O=C–O and C=O to C–O. For tar reforming, the internal pore structure of char-based catalysts is little changed, mainly with the carbon deposit forming on the surface pore structure. The carbon deposit from the reformation of straw tar on the char surface has better reactivity than the inherent carbon structure of ZD coal char and sawdust biochar. There is a positive relationship between the MFBRA–MR specific reactivity and tar catalytic reforming ability of char-based catalysts (decided by the coupling effect in their physical-chemical structure), which can be used to determine the catalytic ability of char-based catalysts on tar reforming directly.

Advances in in situ and ex situ tar reforming with biochar catalysts for clean energy production

2018 ◽  
Vol 2 (2) ◽  
pp. 326-344 ◽  
Author(s):  
Yafei Shen ◽  
Yuhong Fu
Keyword(s):  
Energy Production ◽  
Clean Energy ◽  
Heterogeneous Reactions ◽  
Ex Situ ◽  
Homogeneous And Heterogeneous Reactions ◽  
Biomass Tar ◽  
Tar Reforming

Homogeneous and heterogeneous reactions can occur in the process of in situ or ex situ biomass tar reforming with biochar catalysts.

Mechanism of in-situ dynamic catalysis and selective deactivation of H2O-activated biochar for biomass tar reforming

Fuel ◽  
2020 ◽  
Vol 279 ◽  
pp. 118450 ◽  
Author(s):  
Dongdong Feng ◽  
Yu Zhang ◽  
Yijun Zhao ◽  
Shaozeng Sun ◽  
Jiangquan Wu ◽  
...  
Keyword(s):  
Activated Biochar ◽  
Biomass Tar ◽  
Tar Reforming

scholarly journals Experimental measurements of the permeability characteristics of rare earth ore under the hydro-chemical coupling effect

RSC Advances ◽  
2018 ◽  
Vol 8 (21) ◽  
pp. 11652-11660 ◽  
Author(s):  
Xiaojun Wang ◽  
Yulong Zhuo ◽  
Kui Zhao ◽  
Wen Zhong
Keyword(s):  
Rare Earth ◽  
Coupling Effect ◽  
Experimental Measurements ◽  
Permeability Characteristics ◽  
Leaching Process ◽  
Chemical Coupling ◽  
Coupling Processes

Two coupling processes—solution seepage and chemical replacement—occur in the in situ leaching process of ion-absorbed-rare-earth ore.

Analysis of Casing Strength after Casing Wear in Ultra-Deep Rock Salt Formation

2012 ◽  
Vol 616-618 ◽  
pp. 538-542 ◽  
Author(s):  
Fu Xiang Zhang ◽  
Wei Feng Ge ◽  
Xiang Tong Yang ◽  
Wei Zhang ◽  
Jian Xin Peng
Keyword(s):  
Rock Salt ◽  
Coupling Effect ◽  
Equivalent Stress ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Attrition Rate ◽  
Salt Formation ◽  
Salt Creep ◽  
Casing Wear

To alleviate the problems of casing collapse induced by the coupling effect of rock salt creep and casing wear, the effects of salt creep, attrition rate and casing abrasive position on the equivalent stress on casings in non-uniform in-situ stress field is analyzed by finite-difference model with worn casing, cement and salt formation. It indicates that, creep reduces the yield strength of worn casing to a certain extent; Equivalent stress on casings is bigger and more non-uniform when the abrasion is more serious; Wear position obviously changes the distribution of equivalent stress on casing, and when the wear located along the direction of the minimum in-situ stress, equivalent stress on casing could be the largest that leads to the casing being failed more easily. Equivalent stress on casings increases gradually with creep time increasing and will get to balance in one year or so; In addition, new conclusions are obtained which are different from before: the maximum equivalent stress on casings is in the direction of the minimum horizontal stress, only when the attrition rate of the casing is little; otherwise, it is not. This method could help to improve the wear prediction and design of casings.

Developing an in situ, hydromechanical coupling, true triaxial rock compression tester and investigating the deformation patterns of reservoir bank slopes

2021 ◽  
pp. qjegh2021-043
Author(s):  
Lei Fan ◽  
Meiwan Yu ◽  
Aiqing Wu ◽  
Yihu Zhang
Keyword(s):  
Coupling Effect ◽  
Water Pressure ◽  
Pressure Coefficient ◽  
Hydromechanical Coupling ◽  
Rock Interaction ◽  
True Triaxial ◽  
Rock Structure ◽  
Deformation Patterns

Interactions between water and rocks are the main factors affecting the deformation of rock masses on sloped banks by reservoir impoundment. The technology used in laboratory tests of water-rock interaction mechanisms cannot simulate the coupling of water, the rock structure and the initial stress environment. In this work, we develop an in situ hydromechanical true triaxial rock compression tester and apply it to investigate the coupling response of reservoir bank rocks to changing groundwater levels. The tester is composed of a sealed chamber, loader, reactor, and device for measuring deformation, which are all capable of withstanding high water pressures, and a high-precision servo controller. The maximum axial load, lateral load and water pressure are 12 000 kN, 3 000 kN and 3 MPa, respectively. The dimensions of the test specimens are 310 mm×310 mm×620 mm. The test specimens are grey-black basalts with well-developed cracks from the Xiluodu reservoir area. The results show that increasing water pressure promotes axial compression and lateral expansion, while decreasing water pressure causes axial expansion and lateral compression. A water pressure coefficient, K, is introduced as a measure of the hydromechanical coupling effect (expansion or compression) with changing groundwater level. A mechanical tester can be used to perform accurate field tests of the response of wet rocks to hydromechanical coupling. The test results provide new information about the deformation patterns of rock slopes in areas surrounding high dams and reservoirs.Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes

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