A study on the high-efficiency mixer of the SCR system

A new mixer for a diesel engine after-treatment system is developed to meet the requirements of China VI emission regulation. As for the structure of the mixer, it is surrounded by spiral blades, and the center is staggered with small blades, which is conducive to the crushing of urea droplets and can make the droplets fully mixed with air, improve the conversion efficiency of nitrogen oxides (NOx) and reduce ammonia leakage. The numerical analysis, engine bench test, and vehicle road test were carried out on the after-treatment system equipped with the new mixer. The numerical calculation results show that the velocity uniformity index of the selective catalytic reduction (SCR) carrier can reach 0.98, as well as the ammonia uniformity can reach 0.95, meanwhile, the low wall film height shows excellent anti-crystallization properties. engine bench test results are consistent with numerical results. The crystallization status of the mixer after the vehicle durability test is acceptable and well performed.

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The Large Capacity Pulverized Coal Fired Utility Boiler and the Low NOx Combustion Technology Developments in China in Response to Environmental Challenges

ASME 2011 Power Conference, Volume 1 ◽

10.1115/power2011-55473 ◽

2011 ◽

Author(s):

Hao Zhou ◽

Guiyuan Mo ◽

Kefa Cen

Keyword(s):

High Efficiency ◽

Catalytic Reduction ◽

Pulverized Coal ◽

Large Capacity ◽

Environmental Challenges ◽

Utility Boiler ◽

Integrated Technology ◽

Combustion Technology ◽

Low Nox Combustion ◽

Scr System

Large capacity pulverized coal fired utility boiler technology is in quick developments in China, hundreds of super critical boilers have been constructed in the last several years which can achieve high efficiency and low pollutants emissions. The different types of super critical boilers are introduced in this paper, they include the single-furnace with double fireball corner fired furnace, the wall fired furnace and the tower-type furnace. The low NOx combustion technologies have been widely used to face the environmental challenges. The low NOx technologies employed in pulverized-coal boilers consist of the combustion modification and post-combustion technology. The low NOx combustion modification technology includes the low NOx burner, close coupled over fire air (CCOFA) and separated over fire air (SOFA). The post-combustion technology consists of selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) technologies. Zhejiang University develops integrated low NOx technology, including the low NOx combustion system, SNCR system and SCR system. This integrated technology can reduce the NOx emissions to be lower than 50 mg/Nm3.

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A conceptual design and numerical analysis of the mixerless urea-SCR system

Combustion Engines ◽

10.19206/ce-140539 ◽

2021 ◽

Author(s):

Bartosz Kaźmierski ◽

Krzysztof Górka ◽

Łukasz Kapusta

Keyword(s):

Catalytic Reduction ◽

Film Deposition ◽

Operating Conditions ◽

Navier Stokes ◽

Flow Paths ◽

Wall Film ◽

Compact Design ◽

Scr System ◽

High Degree ◽

Operating Points

In the present study, an innovative design of the urea-selective catalytic reduction (SCR) system without conventional mixing elements was developed. The aim was to obtain a high degree of urea decomposition, and uniform ammonia distribution at the inlet to the catalyst, while minimising the liquid film deposition and keeping the compact design. The concept of the design was based on creating high turbulences and elongating the flow paths of the droplets. The design was verified through a series of numerical simulations based on the Reynolds-averaged Navier–Stokes (RANS) approach and a discrete droplet model (DDM) spray representation. The analysis included various operating conditions as well as subcooled and superheated sprays. A uniform ammonia distribution was achieved regardless of the operating points and spray properties. Additionally, in the case of the flash-boiling injection, a further reduction of the wall film was observed.

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Selective Catalytic Reduction (SCR) System Installation and Commissioning at the Chow II Power Plant in Chowchilla, California

Design, Application, Performance and Emissions of Modern Internal Combustion Engine Systems and Components ◽

10.1115/ices2003-0594 ◽

2003 ◽

Author(s):

Don Newburry ◽

Pat Runnels ◽

Mike Owings

Keyword(s):

Power Plant ◽

Natural Gas ◽

Selective Catalytic Reduction ◽

High Efficiency ◽

Catalytic Reduction ◽

Industrial Applications ◽

Urea Solution ◽

Lean Burn ◽

High Oxygen Content ◽

Scr System

Lean burn, natural gas, reciprocating engines are becoming widely utilized for stationary industrial applications due to their high efficiency and low emissions. However, despite the low engine emissions, some locations still require exhaust after-treatment to meet the local emissions requirements. Due to the high oxygen content (greater than 4%) in the exhaust of lean burn engines, 3-Way (non-selective) catalysts are not suitable to reduce NOx. Selective catalytic reduction (SCR), which utilizes a consumable reductant to reduce NOx over a catalyst, is very effective at reducing NOx and is becoming an accepted technology for large, stationary engine applications. In the summer of 2001, Stewart & Stevenson installed 16 Deutz TGB632V16 natural gas fired engines for NEO Corporation at the Chow II power plant. MIRATECH SCR provided and commissioned 16 selective catalytic reduction systems for these engines using a 40% urea solution as the reductant. This paper describes the installed SCR systems and reports some of the emissions testing results and costs. With the SCR systems in place, the engines were successfully able to meet the permitted exhaust emissions requirements of 0.07 g/bhp-hr of NOx, 0.1 g/bhp-hr of CO, and 0.15 g/bhp-hr of VOC’s (volatile organic compounds) with less than 10 ppmvd of ammonia slip @ 15% O2. Additional measurements were made of formaldehyde and acrolein. Very low levels of these emissions were found after the SCR.

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Study on Calibration Technique of Commercial Vehicles SCR System Based on MAP Diagram

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.229-231.2643 ◽

2012 ◽

Vol 229-231 ◽

pp. 2643-2647 ◽

Cited By ~ 1

Author(s):

Guang Tao Yao ◽

Cheng Lin Deng ◽

Xin Yun Zi ◽

Hai Long Pang ◽

Zi Rong Guo

Keyword(s):

Control System ◽

Catalytic Reduction ◽

Calibration Method ◽

Exhaust Gas ◽

Commercial Vehicles ◽

Calibration Technique ◽

Effective Measure ◽

Emission Regulation ◽

Spray Control ◽

Scr System

Selective Catalytic Reduction (SCR) technology is an effective measure to reduce NOxemissions of diesel for commercial vehicles. The purifying effect of Urea-SCR exhaust gas purification device is related to calibration of the parameter of urea control system. Based on MAP diagram , the calibration method of urea spray control system in Urea-SCR system was studied on. Through verifications of ESC and ETC,it is reflected that calibrated MAP diagram can effectively reduce NOxemissions of diesel if used in the control system and emissions could meet the standards of 4th and 5th stage national emission regulation.

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Development of a 1D Urea-SCR system model coupling with wall film decomposition mechanism based on engine bench test data

Energy Procedia ◽

10.1016/j.egypro.2017.12.235 ◽

2017 ◽

Vol 142 ◽

pp. 3492-3497 ◽

Cited By ~ 3

Author(s):

Boxi Shen ◽

Zhijun Li ◽

Jun Li ◽

Xiangjin Kong ◽

Li He ◽

...

Keyword(s):

Test Data ◽

Decomposition Mechanism ◽

System Model ◽

Bench Test ◽

Model Coupling ◽

Wall Film ◽

Scr System

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Considerations for Ultra-Low NOx Operation in Combined Cycle Plant Retrofits

ASME 2006 Power Conference ◽

10.1115/power2006-88109 ◽

2006 ◽

Author(s):

Dani Fadda ◽

Tom Reis ◽

Mark Buzanowski

Keyword(s):

Velocity Profile ◽

High Efficiency ◽

Catalytic Reduction ◽

Focal Point ◽

Combined Cycle ◽

Environmental Standards ◽

Steam Generators ◽

Combined Cycle Plant ◽

Low Efficiency ◽

Scr System

High efficiency selective catalytic reduction (SCR) systems are designed as retrofits for heat recovery steam generators (HRSG) to comply with increasingly more stringent environmental standards. The retrofits are designed for continuous combined cycle plant operation with ultra low NOx emissions. These retrofits require special design considerations. Maldistribution (non uniformity) in the velocity profile within a high efficiency SCR system is one consideration which is the focal point of this paper. With a specified velocity profile (having a slight maldistribution), high and low efficiency retrofits are compared. It is demonstrated that, while the slight maldistribution in the velocity profile may significantly impact the performance of a high efficiency retrofit, it may be unnoticeable for a low efficiency retrofit.

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Evaluation of an environmentally sustainable UV-assisted water treatment system for the removal of Bacillus globigii spores in water

Water Science & Technology Water Supply ◽

10.2166/ws.2017.165 ◽

2017 ◽

Vol 18 (3) ◽

pp. 968-975

Author(s):

R. G. Silva ◽

J. Szabo ◽

V. Namboodiri ◽

E. R. Krishnan ◽

J. Rodriguez ◽

...

Keyword(s):

Water Treatment ◽

High Efficiency ◽

Membrane Filter ◽

Water Security ◽

Disinfection Byproducts ◽

Treatment System ◽

Health Concern ◽

Environmentally Sustainable ◽

Inorganic Substances ◽

The Impact

Abstract Development of greener water treatment technologies is important for the production of safe drinking water and water security applications, such as decontamination. Chlorine assisted disinfection is common and economical, but can generate disinfection byproducts (DBPs) that may be of health concern. DBPs are formed due to the reaction of chlorine with naturally occurring organic and inorganic substances in water. Currently, various innovative technologies are being developed as alternative approaches for preventing DBPs during water treatment. In this study, we evaluated the effectiveness of a novel combination of high efficiency flow filtration and UV disinfection treatment system for the removal of Bacillus globigii (B. globigii) spores in water. The filtration system consists of a charged membrane filter (CMF) that not only helps to remove suspended particles but also reduces the impact of other impurities including bio organisms. In order to get most performance details, the CMF was evaluated at clean, half-life, and end of life (EOL) conditions along with 100% UV transmittance (UVT). In addition, the effectiveness of the UV system was evaluated as a stand alone system at 100% and 70% EOL intensity. The study was conducted at the US EPA's Test and Evaluation (T&E) Facility in Cincinnati, OH, using B. globigii, a surrogate for B. anthracis spores. This non-chemical environmentally-friendly CMF/UV combination system and the stand alone UV unit showed greater than 6.0 log removal of B. globigii during the tests.

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Simultaneous Optimization of Configuration and Control for a Passive SCR System

Volume 2: Control and Optimization of Connected and Automated Ground Vehicles; Dynamic Systems and Control Education; Dynamics and Control of Renewable Energy Systems; Energy Harvesting; Energy Systems; Estimation and Identification; Intelligent Transportation and Vehicles; Manufacturing; Mechatronics; Modeling and Control of IC Engines and Aftertreatment Systems; Modeling and Control of IC Engines and Powertrain Systems; Modeling and Management of Power Systems ◽

10.1115/dscc2018-9243 ◽

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%.

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