scholarly journals A novel integrated rotary reactor for NOx reduction by CO and air preheating: NOx removal performance and mechanism

AIChE Journal ◽  
2021 ◽  
Author(s):  
Peiliang Sun ◽  
Jianjie Li ◽  
Xingxing Cheng ◽  
Xiangdong Li ◽  
Xiaotao T. Bi ◽  
...  
Keyword(s):  
Nox Reduction ◽  
Nox Removal ◽  
Performance And Mechanism ◽  
Rotary Reactor

scholarly journals Perovskite-Based Catalysts as Efficient, Durable, and Economical NOx Storage and Reduction Systems

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 208
Author(s):  
Jon A. Onrubia-Calvo ◽  
Beñat Pereda-Ayo ◽  
Juan R. González-Velasco
Keyword(s):  
Removal Efficiency ◽  
Diesel Engines ◽  
Nox Reduction ◽  
Platinum Group Metals ◽  
Nox Storage ◽  
Automotive Application ◽  
Nox Removal ◽  
Nox Storage And Reduction ◽  
Nox Storage Capacity ◽  
Nox Removal Efficiency

Diesel engines operate under net oxidizing environment favoring lower fuel consumption and CO2 emissions than stoichiometric gasoline engines. However, NOx reduction and soot removal is still a technological challenge under such oxygen-rich conditions. Currently, NOx storage and reduction (NSR), also known as lean NOx trap (LNT), selective catalytic reduction (SCR), and hybrid NSR–SCR technologies are considered the most efficient control after treatment systems to remove NOx emission in diesel engines. However, NSR formulation requires high platinum group metals (PGMs) loads to achieve high NOx removal efficiency. This requisite increases the cost and reduces the hydrothermal stability of the catalyst. Recently, perovskites-type oxides (ABO3) have gained special attention as an efficient, economical, and thermally more stable alternative to PGM-based formulations in heterogeneous catalysis. Herein, this paper overviews the potential of perovskite-based formulations to reduce NOx from diesel engine exhaust gases throughout single-NSR and combined NSR–SCR technologies. In detail, the effect of the synthesis method and chemical composition over NO-to-NO2 conversion, NOx storage capacity, and NOx reduction efficiency is addressed. Furthermore, the NOx removal efficiency of optimal developed formulations is compared with respect to the current NSR model catalyst (1–1.5 wt % Pt–10–15 wt % BaO/Al2O3) in the absence and presence of SO2 and H2O in the feed stream, as occurs in the real automotive application. Main conclusions are finally summarized and future challenges highlighted.

Research on Methane Decomposition during Gas Reburning for NOx Reduction

2011 ◽  
Vol 356-360 ◽  
pp. 1801-1806
Author(s):  
Hai Ping Xiao ◽  
Qin Jian Yu ◽  
Lei Huang
Keyword(s):  
Free Radicals ◽  
Reaction Mechanism ◽  
Reaction Kinetics ◽  
Nox Reduction ◽  
Main Reaction ◽  
Nox Removal ◽  
Factors Influencing ◽  
Main Factors ◽  
Hydrocarbon Radicals ◽  
Reaction Processes

In order to discover main reaction mechanism of CH4 in NOx removal by methane reburning, reactions between CH4 and NOx were simulated from the point of reaction kinetics. Simulating result demonstrated that reaction temperature and excessive air coefficient were main factors influencing DeNOx efficiency. NO could be directly reduced by free radicals including H, HO2, HCCO and O. Firstly, NO was mainly reduced by HO2.Secondly,NO was mainly reduced by H. Hydrocarbon radicals such as CH3, CH2, C2H4, CH2O, C2H6, CH2CO, HCN, HCNO, HNCO were produced in reaction processes as intermediate products. Lots of free radicals were consumed or produced in reaction and led to concentration variation of NO. At the same time, NO could be directly reduced by hydrocarbon radicals such as CH3, CH2.Therefore, hydrocarbon radicals have important influence on removal efficiency of NOx during methane reburning.

Increasing SCR NOx Removal From 85 to 93% at the Duke Power Cliffside Steam Station

2005 ◽  
Author(s):  
Terence R. Ake ◽  
Clayton A. Erickson ◽  
Linton K. Hutcheson
Keyword(s):  
Bituminous Coal ◽  
Nox Reduction ◽  
Nox Removal ◽  
Anhydrous Ammonia ◽  
The Third ◽  
Catalyst Layers ◽  
Operating Level ◽  
Low Load ◽  
Design Value ◽  
Scr System

Tests were completed at the Duke Power Cliffside Steam Station on the Unit 5 SCR system to increase NOx removal from an initial design value of 85% to an in-use operating level of 93%. These tests took place from May 24 to May 26, 2004 at the start of the third OTAG season for the SCR that was furnished by Riley Power, Inc., a Babcock Power Inc. company. Unit 5 is a balanced draft, subcritical boiler that operates at 590 MW firing eastern bituminous coal. Two SCR reactors are installed at the economizer outlet of the boiler including economizer bypasses for low load operation. Anhydrous ammonia is the reagent for NOx reduction. Each reactor had two initial catalyst layers when the unit was tested.

NOx reduction by CO over ASC catalysts in a simulated rotary reactor: Effect of reaction conditions

2019 ◽  
Vol 92 (3) ◽  
pp. 488-501 ◽  
Author(s):  
Peiliang Sun ◽  
Xingxing Cheng ◽  
Zhiqiang Wang ◽  
Yanhua Lai ◽  
Chunyuan Ma ◽  
...  
Keyword(s):  
Nox Reduction ◽  
Reaction Conditions ◽  
Rotary Reactor

NOx removal by low-cost char pellets: Factors influencing the activity and selectivity towards NOx reduction

Fuel ◽  
2007 ◽  
Vol 86 (7-8) ◽  
pp. 949-956 ◽  
Author(s):  
José María Soriano-Mora ◽  
Agustín Bueno-López ◽  
Avelina García-García ◽  
Ron E. Perry ◽  
Colin E. Snape
Keyword(s):  
Low Cost ◽  
Nox Reduction ◽  
Nox Removal ◽  
Factors Influencing

N-Doped FeCo/ASC catalysts for NOx reduction by CO in a simulated rotary reactor

2019 ◽  
Vol 9 (16) ◽  
pp. 4429-4440 ◽  
Author(s):  
Peiliang Sun ◽  
Xingxing Cheng ◽  
Yanhua Lai ◽  
Zhiqiang Wang ◽  
Chunyuan Ma ◽  
...  
Keyword(s):  
Nox Reduction ◽  
Nitrogen Doped ◽  
Rotary Reactor

Herein, nitrogen-doped activated semi-coke (ASC)-supported ferrum cobalt-co-impregnated catalysts (FeCo/N-ASC) were prepared and tested for deNOx in a simulated rotary reactor.

scholarly journals Reduction of NOx Emission from the Cement Industry in South Korea: A Review

Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 121
Author(s):  
Ji-Hyeon Kim ◽  
Jin-Ho Kim ◽  
Hyo-Sik Kim ◽  
Hyun-Ji Kim ◽  
Suk-Hwan Kang ◽  
...  
Keyword(s):  
South Korea ◽  
Air Pollutants ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Environmental Pollutants ◽  
Post Treatment ◽  
Cement Industry ◽  
Nox Emission ◽  
Pollutant Emission ◽  
Nox Removal

As climates change around the world, concern regarding environmental pollutants emitted into the atmosphere is increasing. The cement industry consistently produces more than 4000 million metric tons of cement per year. However, the problem of air pollutants being emitted from the calcination process is becoming more critical because their amount increases proportionally with cement production. Each country has established regulatory standards for pollutant emission. Accordingly, the cement industry is equipped with facilities to reduce air pollutants, one of which is the NOx removal process. NOx reduction processes under combustion conditions are modified to minimize NOx generation, and the generated NOx is removed through post-treatment. In terms of NOx removal efficiency, the post-treatment process effectively changes the combustion conditions during calcination. Selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) processes are post-treatment environmental facilities for NOx reduction. Accordingly, considering the stringent NOx emission standards in the cement industry, SNCR is essential, and SCR is selectively applied. Therefore, this paper introduces nitrogen oxide among air pollutants emitted from the South Korean cement industry and summarizes the technologies adapted to mitigate the emission of NOx by cement companies in South Korea.

NOx Reduction in a Swirl Combustor Firing Ammonia for a Micro Gas Turbine

2018 ◽  
Author(s):  
Norihiko Iki ◽  
Osamu Kurata ◽  
Takayuki Matsunuma ◽  
Takahiro Inoue ◽  
Taku Tsujimura ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Nox Reduction ◽  
Nox Removal ◽  
Test Rig ◽  
Regenerative Heat ◽  
Ammonia Gas ◽  
Swirl Combustor ◽  
Micro Gas Turbine ◽  
The Rich ◽  
Removal Equipment

Ammonia is expected to be a hydrogen carrier that has potential as a carbon-free fuel. Ammonia is known as a nonignitable fuel, and it is not easy to hold ammonia flames under atmospheric conditions. A demonstration test with the aim of showing the potential of ammonia-fired power plants was conducted using a micro gas turbine. A 50-kW-class turbine system firing kerosene was selected as a base model. More than 40 kW of power generation was achieved by firing ammonia gas or a mixture of ammonia and methane by modifying the combustor, the fuel control device, and the gas turbine startup sequence. The prototype bifuel combustor is a swirl combustor employing a non-premixed flame and a decreased air flow rate near a gas fuel injector for flame holding. Ammonia combustion in the prototype bifuel combustor was enhanced by supplying hot combustion air and by modifying the air inlets. However, the exhaust gases from the ammonia flames had high NOx concentrations. NOx removal equipment using selective catalytic reduction can reduce NOx emission levels to below 10 ppm from more than 1000 ppm (converted value of NOx to 15% O2) as already reported. However, downsizing of NOx removal equipment should be achieved for practical use. Therefore, a low NOx combustor was developed. As the first step of the development of the combustor, flame observation in the gas turbine combustor was tried. Although the observation area was limited, an inhomogeneous swirling orange flame of ammonia gas was observed. Then, a combustor test rig was prepared for a detailed observation of ammonia flame under various combustion conditions. The combustor test rig used a regenerative heat exchanger for heating combustion air, and it used an orifice for pressure drop instead of a turbine. Combustion air and cooling air were supplied from two air compressors. At startup of the combustor test rig, a spark plug was used to ignite non-premixed methane and air. After heating the regenerative heat exchanger, ammonia gas was supplied to the combustor instead of methane gas. The exhaust gases from the combustor were analyzed using FTIR (Fourier transform infrared spectroscopy) under various conditions, such as methane firing, methane–ammonia firing, and ammonia firing. Although there are several concepts for NOx reduction, a rich–lean combustion method was applied first for ammonia firing. The rich–lean combustor modified from the prototype bifuel combustor also could burn ammonia well in cases of both methane–ammonia firing and ammonia firing. The rich–lean combustor succeeded in reducing NOx emission from methane–ammonia combustion to half the value measured in the case of the prototype bifuel combustor.

A simulated rotary reactor for NOx reduction by carbon monoxide over Fe/ZSM-5 catalysts

2017 ◽  
Vol 307 ◽  
pp. 24-40 ◽  
Author(s):  
Xingxing Cheng ◽  
Xingyu Zhang ◽  
Ming Zhang ◽  
Peiliang Sun ◽  
Zhiqiang Wang ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Nox Reduction ◽  
Rotary Reactor

NOx reduction by CO over Fe/ZSM-5: A comparative study of different preparation techniques

2019 ◽  
Vol 18 (2) ◽  
Author(s):  
Jianjie Li ◽  
Mingliang Zhao ◽  
Ming Zhang ◽  
Xingxing Cheng ◽  
Jingcai Chang ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Removal Efficiency ◽  
Nox Reduction ◽  
Acid Sites ◽  
Dynamic Adsorption ◽  
High Catalytic Activity ◽  
Nox Removal ◽  
Desorption Process ◽  
Adsorption Reduction ◽  
Nox Removal Efficiency

Abstract Fe/ZSM-5 catalysts were prepared by three kinds of ion exchange methods: aqueous ion-exchange (AI), hydrothermal ion-exchange (HI) and solid-state ion-exchange (SI). Their catalytic activities were tested for NOx reduction by CO in a separated NOx adsorption-desorption process. In this paper, performances of adsorption, reduction and dynamic adsorption-reduction were all investigated. All three catalysts exhibited good reduction activity at above 300 °C. Fe/ZSM-5(SI) exhibited excellent NOx removal efficiency in the dynamic adsorption-reduction experiments. However, in the dynamic process the adsorption efficiency of Fe/ZSM-5(AI) and the reduction efficiency of Fe/ZSM-5(HI) is not very good. The catalysts were further characterized by SEM, BET, XRD, XRF, XPS and TPD. It was found that the Fe content of the Fe/ZSM-5(SI) was the highest. Further, Fe is supported in the form of Fe2O3 particles. Bronsted acid sites were also playing a major role in the high catalytic activity. TPD and in situ DRIFT experiments show that more Fe loading in α acid sites could result in a higher NOx removal efficiency.

Sign in / Sign up

Export Citation Format

Share Document