Synthesis of Pd0.01FexCe(1-x)/2Zr(1-x)/2Oy catalysts and its catalytic performance for ammonia production of passive SCR reaction

2021 ◽  
Author(s):  
Min Liu ◽  
Ruining Yan ◽  
Xuteng Zhao ◽  
Yinan Wang ◽  
Reggie Zhan ◽  
...  
Keyword(s):  
Treatment Method ◽  
Catalytic Performance ◽  
Ammonia Production ◽  
Scr System ◽  
Passive Scr

The passive ammonia SCR system has been considered as a novel after-treatment method to reduce the emission of NOx and produce ammonia for downstream SCR. A series of Pd0.01FexCe(1-x)/2Zr(1-x)/2Oy catalysts...

Simultaneous Optimization of Configuration and Control for a Passive SCR System

2018 ◽  
Author(s):  
Pingen Chen ◽  
Qinghua Lin
Keyword(s):  
Catalytic Reduction ◽  
Simultaneous Optimization ◽  
Computationally Efficient ◽  
System Architectures ◽  
Aftertreatment System ◽  
In Series ◽  
System Configurations ◽  
Scr System ◽  
And Control ◽  
Passive Scr

The configuration and control of aftertreatment systems have a significant impact on their functionalities and emission control performance. The traditional aftertreatment system configurations, i.e., connections from one aftertreatment subsystem to another subsystem in series, are simple but generally do not yield the optimal aftertreatment system performance. New aftertreatment configurations, in conjunction with new engine and aftertreatment control, can significantly improve engine efficiency and emission reduction performance. However, new configuration design requires human intuition and in-depth knowledge of engine and aftertreatment system design and control. The purpose of this study is to develop a general systematic and computationally-efficient method which enables automated and simultaneous optimization of passive selective catalytic reduction (SCR) system architectures and the associated non-uniform cylinder-to-cylinder combustion (NUCCC) controls based on a newly proposed highly reconfigurable passive SCR model structure and integer partition theory. The proposed method is general enough to account for passive SCR systems with two or more TWC stages. We demonstrate through this case study that the optimized passive SCR configuration, in conjunction with the optimized NUCCC control, can reduce the NH3 specific fuel consumption by up to 21.90%.

scholarly journals Direct Measurement of Ammonia Storage on Passive SCR Systems for Lean Gasoline NOx Reduction Using Radio Frequency Sensing

2019 ◽  
Author(s):  
Paul Ragaller ◽  
Josh Mandelbaum ◽  
Luc Lapenta ◽  
Alexander Sappok ◽  
Josh Pihl ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Real Time ◽  
Gasoline Engine ◽  
Nox Reduction ◽  
Practical Implementation ◽  
Engine Operation ◽  
Ammonia Storage ◽  
Scr System ◽  
Lean Gasoline ◽  
Passive Scr

Abstract Lean gasoline engine operation provides clear efficiency benefits relative to conventional stoichiometric combustion approaches. One of the key hurdles to the widespread, practical implementation of lean gasoline combustion remains the challenge of lean NOx control. One of the potential approaches for controlling NOx emission from lean gasoline engines is the so-called passive selective catalytic reduction (SCR) system. In such systems, periods of rich operation generate ammonia over a three-way catalyst (TWC), which is then adsorbed on the downstream SCR and consumed during lean operation. Brief periods of rich operation must occur in response to the depletion of stored ammonia on the SCR, which requires reliable measurements of the SCR ammonia inventory. Presently, lean exhaust system controls rely on a variety of gas sensors mounted up- and downstream of the catalysts, and which only provide an indirect inference of the operation state. In this study, a radio frequency (RF) sensor was used to provide a direction measurement of the amount of ammonia adsorbed on the SCR in real-time. The RF sensor was calibrated and deployed on a BMW N43B20 4-cylinder lean gasoline engine equipped with a passive SCR system. Brief periods of rich operation performed at lambda values between 0.98 and 0.99 generated the ammonia, subsequently stored on the SCR for consumption during periods of lean operation. The experiments compared real-time measurements of SCR ammonia inventory from the RF sensor with estimates of ammonia coverage derived from exhaust gas composition measurements upstream and downstream of the catalyst. The results showed a high degree of correlation between the RF measurements and SCR ammonia storage inventory, and demonstrated NOx conversion efficiencies above 98%, confirming the feasibility of the concept. Relative to stoichiometric operation, lean-gasoline operation resulted in fuel efficiency gains of up to 10%, which may be further improved through direct feedback control from the RF sensor to optimize lean–rich cycling based on actual, measured SCR ammonia levels.

Cu‐Promoted Pt/Ce 0.5 Zr 0.5 O x Catalyst for Ammonia Production Reaction of Passive SCR from Nitric Oxide and Hydrogen

2022 ◽  
Vol 7 (2) ◽  
Author(s):  
Min Liu ◽  
Ruining Yan ◽  
Yinan Wang ◽  
Xuteng Zhao ◽  
Guo Dongdong ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Ammonia Production ◽  
Passive Scr

Comparison of Lab Versus Engine Tests In the Development of a Highly Efficient Ammonia Formation Catalyst for a Passive SCR System

2015 ◽  
Author(s):  
Gerben Doornbos ◽  
Emma Adams ◽  
Per-Anders Carlsson ◽  
Daniel Dahl ◽  
Mats Laurell ◽  
...  
Keyword(s):  
Highly Efficient ◽  
Scr System ◽  
Ammonia Formation ◽  
Passive Scr ◽  
Versus Engine

Treatment of V2O5/TiO2 by Non-Thermal Plasma: Changes in Surface Characters and Mercury Oxidation Activity

2017 ◽  
Vol 744 ◽  
pp. 519-524
Author(s):  
Lu Liu ◽  
Cheng Hang Zheng ◽  
Xiang Gao
Keyword(s):  
Plasma Treatment ◽  
Catalyst Surface ◽  
Elemental Mercury ◽  
Treatment Method ◽  
Catalytic Performance ◽  
Mercury Removal ◽  
Mercury Oxidation ◽  
Oxidation Activity ◽  
Oxidation Efficiency ◽  
Main Component

The technology for mercury removal in coal-fired power plant is still under development. In the flue gas, elemental mercury is the main component of mercury, and is hard to be removed due to its high volatility and low solubility. So converting Hg0 to Hg2+ in or ahead of the FGD is significant to enhance mercury removal. In this work, plasma treatment method was used to prepare V2O5/TiO2 catalysts for effectively oxidation of Hg0. Plasma treatment of V2O5/TiO2 resulted in the improvement of mercury oxidation activity. The Hg0 oxidation efficiency of the catalysts treated by plasma is over 82% at 300 °C, which is about 30% higher than that of the untreated catalyst. The catalysts were characterized using SEM, BET and EPR. SEM results indicated that plasma treatment can create cracks and small particles on simple surface, however, calcinations cause sintering and agglomeration. The superior catalytic performance is mainly attributed to the formation of particles attached to the catalyst surface, the higher amount of V4+ ions and vacancies on the catalyst surface.

scholarly journals Impact of Titanium Dioxide (TiO2) Modification on Its Application to Pollution Treatment—A Review

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 804 ◽  
Author(s):  
Ruixiang Li ◽  
Tian Li ◽  
Qixing Zhou
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Oxidation ◽  
High Efficiency ◽  
Chemical Properties ◽  
Treatment Method ◽  
Catalytic Performance ◽  
Pure Tio2 ◽  
Inorganic Substances ◽  
Recent Developments ◽  
Physical And Chemical

A high-efficiency method to deal with pollutants must be found because environmental problems are becoming more serious. Photocatalytic oxidation technology as the environmentally-friendly treatment method can completely oxidate organic pollutants into pollution-free small-molecule inorganic substances without causing secondary pollution. As a widely used photocatalyst, titanium dioxide (TiO2) can greatly improve the degradation efficiency of pollutants, but several problems are noted in its practical application. TiO2 modified by different materials has received extensive attention in the field of photocatalysis because of its excellent physical and chemical properties compared with pure TiO2. In this review, we discuss the use of different materials for TiO2 modification, highlighting recent developments in the synthesis and application of TiO2 composites using different materials. Materials discussed in the article can be divided into nonmetallic and metallic. Mechanisms of how to improve catalytic performance of TiO2 after modification are discussed, and the future development of modified TiO2 is prospected.

scholarly journals Boosting the Catalytic Performance of Co/Mg/La Catalyst for Ammonia Synthesis by Selecting a Pre-Treatment Method

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 941
Author(s):  
Hubert Ronduda ◽  
Magdalena Zybert ◽  
Wojciech Patkowski ◽  
Andrzej Ostrowski ◽  
Przemysław Jodłowski ◽  
...  
Keyword(s):  
Ammonia Synthesis ◽  
Treatment Method ◽  
Catalytic Performance ◽  
Adsorption Properties ◽  
Detailed Characterization ◽  
Calcination Process ◽  
Catalytic Behavior ◽  
Characterization Methods ◽  
Pre Treatment ◽  
Catalytic Performances

The influence of the calcination process on the physicochemical properties and catalytic behavior of the Co/Mg/La catalysts for ammonia synthesis has been investigated. The catalysts were prepared using the different thermal pre-treatment methods prior to the activation, i.e., drying and calcination, and the respective activities for ammonia synthesis were assessed. It was found out that changing from air calcination prior to activation to direct activation of the co-precipitated species led to the different catalytic performances. The most favorable catalytic performance was achieved with Co/Mg/La prepared by calcination in air. Detailed characterization methods, employing e.g., XRPD, H2-TPD, N2-TPD, CO2-TPD, SEM, and TEM, showed that the superior catalytic behavior of this catalyst was attributed to its strong basicity and favorable adsorption properties toward hydrogen and nitrogen.

Synthesis of hierarchical GaZSM-5 zeolites by HCl treatment method and their catalytic performance in methanol aromatization

2021 ◽  
Author(s):  
Feng Zhou ◽  
Huixia Ma ◽  
Zheng Han ◽  
Fangwei Ma ◽  
Guang Wu
Keyword(s):  
Hydrochloric Acid ◽  
Treatment Method ◽  
Catalytic Performance ◽  
Isomorphic Substitution

A series of ZSM-5 samples exhibiting isomorphic substitution with Ga and containing both micropores and mesopores was synthesized by a posttreatment method involving different concentrations of hydrochloric acid. Various techniques...

Sign in / Sign up

Export Citation Format

Share Document