NOx Reduction by In Situ Catalytic Reduction in the Combustion Process of Coke

2012 ◽  
Vol 610-613 ◽  
pp. 2104-2108
Author(s):  
Yan Guang Chen ◽  
Hong Jing Han ◽  
Jia Lu ◽  
Jin Lian Li ◽  
Ying Chen ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Nox Emission ◽  
Impregnation Method ◽  
Supporting Effect ◽  
Catalytic Effects ◽  
Co Emission

A new method, NOx reduction by in-situ catalytic effects of additives loaded in coke, was proposed. A series of coke samples with different loading amounts of CaCl2, Ce(SO4)2 and La2(SO4)3 were prepared by using the impregnation method, the rules of NOx and CO emissions in the combustion were investigated. The results show that CaCl2, Ce(SO4)2 and La2(SO4)3 play in-situ catalytic effects on the NOx reduction reactions. When the loading of CaCl2 is 4.0%, the amount of NOx emission is reduced by 13.9%. When the loading of Ce(SO4)2is 4.0%, the amount of NOx emission decreases by 17.2%. When the loading of La2(SO4)3 is 4.0%, the amount of NOx emission decreases by 8.7%. Ce(SO4)2 possesses the combustion-supporting effect. As 4.0% Ce(SO4)2 in coke, the CO emission is reduced by 26%, which improves the combustion efficiency of coke.

Effects of Alkali and Alkaline Earth Metals on NOx Reduction in Coke Combustion

2013 ◽  
Vol 634-638 ◽  
pp. 522-525 ◽  
Author(s):  
Yan Guang Chen ◽  
Hong Jing Han ◽  
Jia Lu ◽  
Dan Dan Li ◽  
Jin Lian Li ◽  
...  
Keyword(s):  
Alkaline Earth ◽  
Nox Reduction ◽  
Combustion Process ◽  
Fixed Bed ◽  
Alkaline Earth Metals ◽  
Reduction Ratio ◽  
Nox Emission ◽  
Fixed Bed Reactor ◽  
Impregnation Method ◽  
Loading Amount

A series of coke samples with loading alkali and alkaline earth metals were prepared by the impregnation method, the NOx emission were investigated in a silica fixed bed reactor in the combustion process of raw coke and coke modified by Na, K, Ca and Mg. The results show that Na, K, Ca and Mg play in-situ catalytic effects on the NOx reduction reactions. When the loading amount of Na2CO3 is 2.0%, the NOx reduction ratio was around 17.4%, when the loading of K2CO3 is 2.0%, the amount of NOx emission is reduced by 26.5%. When the loading of CaCl2 is 2.0%, the amount of NOx emission is reduced by 22.3%. When the loading of MgCl2 is 2.0%, the NOx reduction ratio is about 10.9%.

Investigation of Fuel Lean Reburning

2009 ◽  
Author(s):  
Hak Young Kim ◽  
Seung Wook Baek
Keyword(s):  
Experimental Study ◽  
Heat Input ◽  
Nox Reduction ◽  
Combustion Process ◽  
Total Heat ◽  
Nox Emission ◽  
Fuel Saving ◽  
Liquefied Petroleum Gas ◽  
Zero Level ◽  
Co Emission

The present work is focused on a fuel-lean reburn system to experimentally control NOx emission from combustion process. Fuel-lean reburn system is found here to be able to replace a conventional reburning technique due to reburn fuel saving. In the conventional reburning process the NOx emission is reduced up to 45% using 20∼25% reburn fuel of total heat input, while CO emission is restricted within acceptable limits by adopting additional air supplying system. However, in the fuel-lean reburn system, by contrast, the amount of injected reburn fuel into the reburning zone is low enough to maintain overall fuel-lean condition in the furnace, so that no additional air system is required, and CO emission can be maintained at almost zero level. In this study, an experimental study has been done to examine the formation characteristics of NOx in a lab scale combustor (15kW) with various oxygen enhanced combustion conditions. LPG (liquefied Petroleum Gas) was used as main fuel and reburn fuel. Finally, the current fuel-lean reburn system, even with only an amount of reburn fuel of 13% of total heat input, was observed to achieve a maximum of 48% in NOx reduction.

scholarly journals In Situ DRIFTS Studies of NH3-SCR Mechanism over V2O5-CeO2/TiO2-ZrO2 Catalysts for Selective Catalytic Reduction of NOx

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1307 ◽  
Author(s):  
Yaping Zhang ◽  
Xiupeng Yue ◽  
Tianjiao Huang ◽  
Kai Shen ◽  
Bin Lu
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Oxygen Storage ◽  
In Situ Drifts ◽  
Nh3 Scr ◽  
Nh3 Adsorption ◽  
Reduction Of Nox ◽  
Zro2 Catalyst

TiO2-ZrO2 (Ti-Zr) carrier was prepared by a co-precipitation method and 1 wt. % V2O5 and 0.2 CeO2 (the Mole ratio of Ce to Ti-Zr) was impregnated to obtain the V2O5-CeO2/TiO2-ZrO2 catalyst for the selective catalytic reduction of NOx by NH3. The transient activity tests and the in situ DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) analyses were employed to explore the NH3-SCR (selective catalytic reduction) mechanism systematically, and by designing various conditions of single or mixing feeding gas and pre-treatment ways, a possible pathway of NOx reduction was proposed. It was found that NH3 exhibited a competitive advantage over NO in its adsorption on the catalyst surface, and could form an active intermediate substance of -NH2. More acid sites and intermediate reaction species (-NH2), at lower temperatures, significantly promoted the SCR activity of the V2O5-0.2CeO2/TiO2-ZrO2 catalyst. The presence of O2 could promote the conversion of NO to NO2, while NO2 was easier to reduce. The co-existence of NH3 and O2 resulted in the NH3 adsorption strength being lower, as compared to tests without O2, since O2 could occupy a part of the active site. Due to CeO2’s excellent oxygen storage-release capacity, NH3 adsorption was weakened, in comparison to the 1 wt. % V2O5-0.2CeO2/TiO2-ZrO2 catalyst. If NOx were to be pre-adsorbed in the catalyst, the formation of nitrate and nitro species would be difficult to desorb, which would greatly hinder the SCR reaction. All the findings concluded that NH3-SCR worked mainly through the Eley-Rideal (E-R) mechanism.

NOx Emission of Diesel Fuel Blended with Different Saturation Degrees of Biofuel and with Oxygenator

2014 ◽  
Vol 660 ◽  
pp. 397-401 ◽  
Author(s):  
Mohd Fareez Edzuan bin Abdullah ◽  
Mohd Hisyamuddin bin Sulaiman ◽  
Noor Aliah Binti Abdul Majid
Keyword(s):  
Diesel Fuel ◽  
Flue Gas ◽  
Combustion Process ◽  
Nox Emission ◽  
Dominant Factor ◽  
Compression Ignition ◽  
Nox Formation ◽  
Fuel Blends ◽  
Combustion Tests ◽  
Co Emission

This paper discusses the nitrogen oxides (NOx) emission characteristics of compression ignition diesel engine operating on diesel fuel blends with different saturation degrees of biofuel and with methanol. In order to investigate the dominant factor of increased NOx in biofuels, diesel combustion tests were conducted under idling condition and the tailpipe exhaust emissions were measured by a flue gas analyzer. The general trend where NOx emission increased and reduced carbon monoxide (CO) emission in the biofuel and methanol blend cases were observed. The NOx emission levels increased as the biofuel saturation degree decreased, where it may be suggested that the prompt NOx mechanism is significant in total NOx formation of biofuel combustion process.

scholarly journals In situ measurements of O<sub>2</sub> and CO eq.  in cement kilns

2017 ◽  
Vol 6 (2) ◽  
pp. 327-330 ◽  
Author(s):  
Olga Driesner ◽  
Fred Gumprecht ◽  
Ulrich Guth
Keyword(s):  
Flue Gas ◽  
Oxygen Sensor ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Raw Material ◽  
Delayed Response ◽  
Plant Operator ◽  
In Situ Sensors ◽  
Cement Kilns

Abstract. The simultaneous in situ measurement of O2 and CO eq.  in cement kilns is a great challenge due to the high process temperatures and high dust load. The standard method for measurement for flue gas in cement kilns is extractive. Extractive measurements have a higher response time due to the flue gas conditioning including the length of heated extraction lines for electrochemical or optical analysis. This delayed response is not optimal for fast process control.A probe was developed for this purpose in which the in situ solid electrolyte oxygen sensor and an in situ CO eq.  mixed potential sensor are implemented. Due to the high temperatures, the probe is cooled by a water–coolant mixture. In order to prevent deposits of raw material forming and sintering on the probe, it rotates 90° in programmable intervals. In addition, an automated probe plunger pneumatically removes plugging at the probe flue gas entrance, also in programmable intervals. These self-cleaning functions allow the probe to continually stay in the process for combustion optimisation (low excess O2 and CO) and enable the plant operator to measure additional process-related gas components (NO, SO2, HCl etc.) and optimise the SNCR (selective non-catalytic reduction) for NOx reduction. Combustion air supply can be adapted very quickly due to the in situ sensors, which has been demonstrated by a CEMTEC® probe over years (Märker Cement Harburg, 2017).

scholarly journals Effects of Ce over TiO2 supported MnOx-based Catalyst for NOx Reduction by Ammonia

2020 ◽  
Vol 185 ◽  
pp. 04026
Author(s):  
Zhi Liu ◽  
Yunqi Liu
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Catalyst Design ◽  
No Oxidation ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Positive Role ◽  
Fast Scr ◽  
Insight Into

Ce modified MnOx-based catalysts have attracted much attention due to its high activity for selective catalytic reduction of NOx by NH3 (NH3-SCR) at low-temperatures. However, the most important role of Ce on the NH3-SCR performance of MnOx-based catalysts has not been confirmed. Herein, the typical Ce-Mn/TiO2 catalyst was synthesized through incipient-wetness impregnation method, the positive role of Ce on Ce-Mn/TiO2 catalyst in the NH3-SCR process was revealed by combining different activity tests (including NO oxidation and NH3 oxidation) and characterizations (including XRD, XPS and He-TPDMS experiments). It was found that the introduction of Ce can promote the dispersion of MnOx on TiO2 support. Meanwhile, the doping of Ce in MnOx can also increase the content of Mn4+ species. The Mn4+ species plays a crucial role in NO oxidation reaction, which can trigger the “Fast SCR” reaction and promote the conversion of NOx. This work provides insight into the catalyst design for NH3-SCR process at low-temperature.

scholarly journals Modeling of pulverized coal combustion for in-furnace NOx reduction and flame control

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 597-615 ◽  
Author(s):  
Srdjan Belosevic ◽  
Ivan Tomanovic ◽  
Nenad Crnomarkovic ◽  
Aleksandar Milicevic
Keyword(s):  
Coal Combustion ◽  
Numerical Study ◽  
Nox Reduction ◽  
Combustion Process ◽  
Pulverized Coal ◽  
Operating Conditions ◽  
Nox Emission ◽  
Differential Model ◽  
No Formation ◽  
Turbulent Reactive Flows

A cost-effective reduction of NOx emission from utility boilers firing pulverized coal can be achieved by means of combustion modifications in the furnace. It is also essential to provide the pulverized coal diffusion flame control. Mathematical modeling is regularly used for analysis and optimization of complex turbulent reactive flows and mutually dependent processes in coal combustion furnaces. In the numerical study, predictions were performed by an in-house developed comprehensive three-dimensional differential model of flow, combustion and heat/mass transfer with submodel of the fuel- and thermal-NO formation/ destruction reactions. Influence of various operating conditions in the case-study utility boiler tangentially fired furnace, such as distribution of both the fuel and the combustion air over the burners and tiers, fuel-bound nitrogen content and grinding fineness of coal were investigated individually and in combination. Mechanisms of NO formation and depletion were found to be strongly affected by flow, temperature and gas mixture components concentration fields. Proper modifications of combustion process can provide more than 30% of the NOx emission abatement, approaching the corresponding emission limits, with simultaneous control of the flame geometry and position within the furnace. This kind of complex numerical experiments provides conditions for improvements of the power plant furnaces exploitation, with respect to high efficiency, operation flexibility and low emission.

scholarly journals Effect of Ce-modified Fe/ZSM-5 zeolite for selective catalytic reduction of NOx by ammonia

2020 ◽  
Vol 218 ◽  
pp. 03032
Author(s):  
Chenxi Li ◽  
Fanwei Meng ◽  
Qing Ye
Keyword(s):  
Selective Catalytic Reduction ◽  
Photoelectron Spectroscopy ◽  
Catalytic Reduction ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Impregnation Method ◽  
Adsorption Ability ◽  
In Situ Drifts ◽  
X Ray

A series of xCe-Fe/ZSM-5 (x = 0, 0.25, 0.5 wt%) samples were prepared by the impregnation method, and the catalytic activity was evaluated by the selective catalytic reduction of NOx with ammonia (NH3-SCR). The physicochemical properties of prepared samples were characterized by various techniques such as X-ray diffraction (XRD), Brunner-Emmet-Teller (BET) measurement, hydrogen temperatureprogrammed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), ammonia temperatureprogrammed desorption (NH3-TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). XRD and BET results demonstrated that Ce and Fe species were uniform dispersed on the surface of the ZSM-5 zeolite and the micropore structure of ZSM-5 was still maintained. H2-TPR analysis indicated that the doping of Ce created more isolated Ce4+ and Fe3+ on the surface of catalysts, and the abundant Ce4+ and Fe3+ could enhance the reduction ability of catalysts. XPS analysis suggested that the doping of Ce could generate more oxygen vacancies, thereby increasing the number of chemisorption oxygen. According to the in-situ DRIFTS and NH3-TPD results, Ce species provided more acidic sites, which is beneficial to the NH3 adsorption ability of ZSM-5 zeolite. Additionally, the abundant chemisorption oxygen, medium and strong Brønsted acid sites, excellent NH3 adsorption ability and outstanding reduction property are beneficial to the NH3-SCR reaction. Among all prepared samples, the 0.25Ce-Fe/ZSM-5 sample possessed the widest reaction temperature window and the best catalytic performance (NO conversion over 98% at 350-450 °C), which was associated with the abundant acid sites and remarkable adsorption ability of NH3, outstanding redox ability and abundant chemisorption oxygen after the doping of Ce.

Comparison of NOx Emissions Decreasing Methods for Biofuel Boilers

2017 ◽  
Author(s):  
Titas Sereika ◽  
Kęstutis Buinevičius ◽  
Adolfas Jančauskas
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Main Idea ◽  
Nox Emissions ◽  
Reduction Methods ◽  
Reduction Of Nox ◽  
Secondary Air ◽  
Nitrogen Oxides Reduction ◽  
Gas Recirculation ◽  
Co Emission

The main idea of research is to figure out the emissions of nitrogen oxides reduction using various type of reduction methods. In experiments were used NOx reduction methods: high CO emissions generation, flue gas recirculation, water and water vapor supply, selective non-catalytic reduction (SNCR), and SNCR with flammable additive. This study presents emission and combustion results obtained burning furniture production waste which generates higher rate of NOx emissions. The result of research shows, that CO emission has the biggest impact factor -on reducing NOx emission. Burning fuel in combustion zone with first and secondary air ratio (40/60) and using methods for higher generation CO emissions reached 3.000 mg/m3 which reduces NOx emissions up to 83%. Using selective non-catalytic reduction with traditional and flammable additives reduction of NOx emissions reached up to 55%.

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.

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