Reconstructing the direct relations between various structure-directing agents and low-temperature hydrothermal durability over Cu-SAPO-34 during NH3-SCR reaction

2022 ◽  
Author(s):  
Shoute Zhang ◽  
Ying Meng ◽  
Lei Pang ◽  
Qianzhao Ding ◽  
Zhen Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Commercial Application ◽  
Nh3 Scr ◽  
Structure Directing Agents ◽  
Application Prospects

The Cu-SAPO-34 catalysts used for NH3-SCR reaction deteriorated exposed to moisture environment at low temperatures (<100 °C), which seriously hindered its commercial application prospects. In this work, the Cu-SAPO-34 catalysts...

Effect of various structure directing agents (SDAs) on low-temperature deactivation of Cu/SAPO-34 during NH3-SCR reaction

2018 ◽  
Vol 8 (12) ◽  
pp. 3090-3106 ◽  
Author(s):  
Jungwon Woo ◽  
Kirsten Leistner ◽  
Diana Bernin ◽  
Homayoun Ahari ◽  
Mark Shost ◽  
...  
Keyword(s):  
Low Temperature ◽  
Nh3 Scr ◽  
Structure Directing Agents

Cu/SAPO-34(TEA) only exhibited minor deactivation and mostly recovered its original activities, while Cu/SAPO-34(MO) showed major deactivation and was not fully regenerated during low temperature NH3-SCR reaction.

scholarly journals A Study on Mn-Fe Catalysts Supported on Coal Fly Ash for Low-Temperature Selective Catalytic Reduction of NOX in Flue Gas

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1399
Author(s):  
Xiaoxu Duan ◽  
Jinxiao Dou ◽  
Yongqi Zhao ◽  
Salman Khoshk Rish ◽  
Jianglong Yu
Keyword(s):  
Reaction Mechanism ◽  
Fly Ash ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Low Temperatures ◽  
Catalytic Reduction ◽  
Coal Fly Ash ◽  
Fixed Bed Reactor ◽  
Main Reaction ◽  
Nh3 Scr

A series of Mn0.15Fe0.05/fly-ash catalysts have been synthesized by the co-precipitation method using coal fly ash (FA) as the catalyst carrier. The catalyst showed high catalytic activity for low-temperature selective catalytic reduction (LTSCR) of NO with NH3. The catalytic reaction experiments were carried out using a lab-scale fixed-bed reactor. De-NOx experimental results showed the use of optimum weight ratio of Mn/FA and Fe/FA, resulted in high NH3-SCR (selective catalytic reduction) activity with a broad operating temperature range (130–300 °C) under 50000 h−1. Various characterization methods were used to understand the role of the physicochemical structure of the synthesized catalysts on their De-NOx capability. The scanning electron microscopy, physical adsorption-desorption, and X-ray photoelectron spectroscopy showed the interaction among the MnOx, FeOx, and the substrate increased the surface area, the amount of high valence metal state (Mn4+, Mn3+, and Fe3+), and the surface adsorbed oxygen. Hence, redox cycles (Fe3+ + Mn2+ ↔ Mn3+ + Fe2+; Fe2+ + Mn4+ ↔ Mn3+ + Fe3+) were co-promoted over the catalyst. The balance between the adsorption ability of the reactants and the redox ability can promote the excellent NOx conversion ability of the catalyst at low temperatures. Furthermore, NH3/NO temperature-programmed desorption, NH3/NO- thermo gravimetric-mass spectrometry (NH3/NO-TG-MS), and in-situ DRIFTs (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) results showed the Mn0.15Fe0.05/FA has relatively high adsorption capacity and activation capability of reactants (NO, O2, and NH3) at low temperatures. These results also showed that the Langmuir–Hinshelwood (L–H) reaction mechanism is the main reaction mechanism through which NH3-SCR reactions took place. This work is important for synthesizing an efficient and environmentally-friendly catalyst and demonstrates a promising waste-utilization strategy.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

Superconducting Wind Generators with Capacities of 10 MW and Larger

2020 ◽  
Vol 10 (10) ◽  
pp. 59-67
Author(s):  
Victor N. ANTIPOV ◽  
◽  
Andrey D. GROZOV ◽  
Anna V. IVANOVA ◽  
◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Wind Power ◽  
State Of The Art ◽  
Superconducting Materials ◽  
Commercial Application ◽  
Synchronous Generators ◽  
High Temperature Superconducting ◽  
Wind Generators ◽  
Main Factor

The overall dimensions and mass of wind power units with capacities larger than 10 MW can be improved and their cost can be decreased by developing and constructing superconducting synchronous generators. The article analyzes foreign conceptual designs of superconducting synchronous generators based on different principles: with the use of high- and low-temperature superconductivity, fully superconducting or only with a superconducting excitation system, and with the use of different materials (MgB2, Bi2223, YBCO). A high cost of superconducting materials is the main factor impeding commercial application of superconducting generators. In view of the state of the art in the technology for manufacturing superconductors and their cost, a conclusion is drawn, according to which a synchronous gearless superconducting wind generator with a capacity of 10 MW with the field winding made of a high-temperature superconducting material (MgB2, Bi-2223 or YBCO) with the «ferromagnetic stator — ferromagnetic rotor» topology, with the stator diameter equal to 7—9 m, and with the number of poles equal to 32—40 has prospects for its practical use in the nearest future.

INVAR M93

Alloy Digest ◽  
2008 ◽  
Vol 57 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Low Temperatures ◽  
Bend Strength ◽  
Temperature Performance ◽  
Ni Content ◽  
Precision Alloys ◽  
Ni Alloy

Abstract Invar is an Fe-Ni alloy with 36% Ni content that exhibits the lowest expansion of known metals from very low temperatures up to approximately 230 deg C (445 deg F). Invar M93 is a cryogenic Invar with improved weldability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear and bend strength as well as fracture toughness and fatigue. It also includes information on low temperature performance as well as forming and joining. Filing Code: FE-143. Producer or source: Metalimphy Precision Alloys.

The synergistic effects between Ce and Cu in CuyCe1−yW5Ox catalysts for enhanced NH3-SCR of NOx and SO2 tolerance

2019 ◽  
Vol 9 (3) ◽  
pp. 718-730 ◽  
Author(s):  
Jian-Wen Shi ◽  
Yao Wang ◽  
Ruibin Duan ◽  
Chen Gao ◽  
Baorui Wang ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Selective Catalytic Reduction ◽  
Low Temperatures ◽  
Catalytic Reduction ◽  
Synergistic Effects ◽  
Reduction Of No ◽  
Nh3 Scr ◽  
So2 Tolerance ◽  
Scr Of Nox

Non-manganese-based metal oxides are promising catalysts for the NH3-SCR (selective catalytic reduction) of NOx at low temperatures.

scholarly journals Insight into the Promoting Role of Er Modification on SO2 Resistance for NH3-SCR at Low Temperature over FeMn/TiO2 Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 618
Author(s):  
Huan Du ◽  
Zhitao Han ◽  
Xitian Wu ◽  
Chenglong Li ◽  
Yu Gao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalyst Surface ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Tio2 Catalyst ◽  
Nh3 Scr ◽  
Nh3 Adsorption ◽  
So2 Resistance ◽  
Fast Scr

Er-modified FeMn/TiO2 catalysts were prepared through the wet impregnation method, and their NH3-SCR activities were tested. The results showed that Er modification could obviously promote SO2 resistance of FeMn/TiO2 catalysts at a low temperature. The promoting effect and mechanism were explored in detail using various techniques, such as BET, XRD, H2-TPR, XPS, TG, and in-situ DRIFTS. The characterization results indicated that Er modification on FeMn/TiO2 catalysts could increase the Mn4+ concentration and surface chemisorbed labile oxygen ratio, which was favorable for NO oxidation to NO2, further accelerating low-temperature SCR activity through the “fast SCR” reaction. As fast SCR reaction could accelerate the consumption of adsorbed NH3 species, it would benefit to restrain the competitive adsorption of SO2 and limit the reaction between adsorbed SO2 and NH3 species. XPS results indicated that ammonium sulfates and Mn sulfates formed were found on Er-modified FeMn/TiO2 catalyst surface seemed much less than those on FeMn/TiO2 catalyst surface, suggested that Er modification was helpful for reducing the generation or deposition of sulfate salts on the catalyst surface. According to in-situ DRIFTS the results of, the presence of SO2 in feeding gas imposed a stronger impact on the NO adsorption than NH3 adsorption on Lewis acid sites of Er-modified FeMn/TiO2 catalysts, gradually making NH3-SCR reaction to proceed in E–R mechanism rather than L–H mechanism. DRIFTS.

Promotional effect and mechanism of the modification of Ce on the enhanced NH3-SCR efficiency and the low temperature hydrothermal stability over Cu/SAPO-34 catalysts

2021 ◽  
Vol 617 ◽  
pp. 118110
Author(s):  
Bin Guan ◽  
Han Jiang ◽  
Xuesong Peng ◽  
Yanfei Wei ◽  
Ziqian Liu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Hydrothermal Stability ◽  
Nh3 Scr ◽  
Promotional Effect

Lead poisoning and regeneration of Mn-Ce/TiO2 catalysts for NH3-SCR of NO at low temperature

2021 ◽  
Vol 49 (1) ◽  
pp. 113-120
Author(s):  
Dong-jie YAN ◽  
Tong GUO ◽  
Ya YU ◽  
Zhao-hui CHEN
Keyword(s):  
Low Temperature ◽  
Lead Poisoning ◽  
Nh3 Scr ◽  
Scr Of No

FEC-LiTFSI-Pyr1ATFSI Ionic Liquid Electrolyte to Improve Low Temperature Performance of Lithium-Ion Batteries

2014 ◽  
Vol 986-987 ◽  
pp. 80-83
Author(s):  
Xiao Xue Zhang ◽  
Zhen Feng Wang ◽  
Cui Hua Li ◽  
Jian Hong Liu ◽  
Qian Ling Zhang
Keyword(s):  
Low Temperature ◽  
Lithium Ion Batteries ◽  
Low Temperatures ◽  
Freezing Point ◽  
Lithium Ion ◽  
Liquid Electrolyte ◽  
Capacity Retention ◽  
Composite Electrolyte ◽  
Ionic Liquid Electrolyte ◽  
Fluoroethylene Carbonate

N-methyl-N-allylpyrrolidinium bis (trifluoromethanesulfonyl) imide (PYR1ATFSI) with substantial supercooling behavior is synthesized to develop low temperature electrolyte for lithium-ion batteries. Additive fluoroethylene carbonate (FEC) in LiTFSI/PYR1ATFSI/EC/PC/EMC is found that it can reduce the freezing point. LiFePO4/Li coin cells with the FEC-PYR1ATFSI electrolyte exhibit good capacity retention, reversible cycling behavior at low temperatures. The good performance can be attributed to the decrease in the freezing point and the polarization of the composite electrolyte.

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