scholarly journals Effect of Absorbents on NOx Removal through Polyvinylidene Fluoride (PVDF) Hollow Fiber Membrane Modules

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Irfan Purnawan ◽  
Sutrasno Kartohardjono ◽  
Levana Wibowo ◽  
Annisa Faiza Ramadhani ◽  
Woei Jye Lau ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Removal Efficiency ◽  
Polyvinylidene Fluoride ◽  
Gas Flow ◽  
Hollow Fiber Membrane ◽  
Sodium Chlorate ◽  
Sodium Chlorite ◽  
Nox Removal ◽  
Wet Process ◽  
Nox Removal Efficiency

NOx (NO and NO2) are air toxins that endanger life and represent a hazard to the environment, such as photochemical smog, global warming, acid rain, ozone depletion, and the occurrence of respiratory infections. Some technological strategies to diminish NOx emissions to meet regulations depend on two techniques: the dry process and the wet process. This study applies polyvinylidene fluoride (PVDF) hollow fiber membrane modules as a medium to remove NOx from solutions containing several absorbents such as hydrogen peroxide and nitric acid (H2O2-HNO3) solutions, sodium chlorite and sodium hydroxide (NaClO2-NaOH) solutions, and sodium chlorate and sodium hydroxide (NaClO3-NaOH) solutions. The experimental results showed that the oxidant’s strength influences NOx removal efficiency, where the absorbent solutions containing hydrogen peroxide had the highest removal efficiency as hydrogen peroxide is the most potent oxidant, followed by sodium chlorite and sodium chlorate. The three pairs of absorbents also gave a high NOx removal efficiency (above 90%), which means that all the absorbents used in the study are very potential to be used to diminish NOx via the wet process. NOx removal efficiency at the same feed gas flow rate increased as the number of fiber and absorbent concentrations is increased. However, NOx removal efficiency is reduced as the feed gas flow rate is increased at the same membrane module and absorbent concentration.

scholarly journals Combined Removal Of NOx And SO2 From Flue Gas At Low Temperature

2018 ◽  
Vol 53 ◽  
pp. 04038 ◽  
Author(s):  
Zhipeng Xue ◽  
Hao Chen ◽  
Minmin Zhao
Keyword(s):  
Removal Efficiency ◽  
Flue Gas ◽  
Gas Flow ◽  
Ph Value ◽  
National Standards ◽  
Raw Material ◽  
Nox Removal ◽  
Gas Temperature ◽  
Solution Ph ◽  
Nox Removal Efficiency

A method was proposed to remove NOx and SO2 in flue gas by using the sulfinyl functional group as a catalyst. Ozone is introduced into the flue gas to oxidize NO. Soluble NO2 and SO2 reacted with ammonia to form ammonium sulfate and ammonium nitrate, which were the raw material of the compound fertilizer. A small pilot is built in a container that can be easily transported to power plant and extracts the actual flue gas directly from the gas duct. In order to obtain the best the SO2 and NOX removal efficiency in this experiment, many parameters were changed. Such as flue gas flow, ozone / NOX ratio, liquid-gas ratio, flue gas temperature, catalyst type, catalyst concentration, solution pH value. Results indicated that SO2 was cleaned up quite efficiently and the removal efficiency was nearly 99% under all conditions. the best NOX removal efficiency can reach 88%. The NOX removal efficiency depended primarily on ozone / NOX ratio, and the temperature of flue gas also had influence on the NOX removal efficiency. The optimum pH range is 5.6-6.3. After inspection by authoritative institutions, the quality of fertilizers is superior to national standards.

Influence of gas flow patterns on NOx removal efficiency

1998 ◽  
Vol 52 (1-6) ◽  
pp. 339-343 ◽  
Author(s):  
A.G. Chmielewski ◽  
B. Tymiñski ◽  
A. Dobrowolski ◽  
S. Sato ◽  
O. Tokunaga ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Gas Flow ◽  
Flow Patterns ◽  
Nox Removal ◽  
Nox Removal Efficiency

Industrial Demonstration on NOx Removal by Gas Reburning in a 50MWE Tangential Pulverizing Coal-Fired Boiler

2006 ◽  
Author(s):  
Xiaofeng Lu ◽  
Hanzhou Liu ◽  
R. S. Amano
Keyword(s):  
Removal Efficiency ◽  
Gas Flow ◽  
Low Rank ◽  
Nox Removal ◽  
Ball Mills ◽  
Burn Out ◽  
Nox Removal Efficiency ◽  
Removal Technologies ◽  
Available Technology ◽  
Industrial Demonstration

More than 70% of NOx in air comes from various coal burning processes. Among NOx removal technologies, gas-reburning technology have been proven to be an available technology by all industrial demonstrations in USA and Europe. To identify the feasibility of NOx removal with gas reburning technology for low rank coal in China, an industrial demonstration test of NOx removal with the gas reburning technology was carried in a 220t/h tangential pulverizing coal-fired boiler in JiangYou power plant from 2002 to 2004. In the test, reburning gas and burn out air were arranged at the front and rear walls of the furnace in a creative way. It was the first time in the world for such an arrangement method of reburning gas and burn out air were applied. The relationship of NOx removal efficiency with the nature gas flow rate, the Oxygen content in the furnace and operating methods of ball mills (or the Third Air) were tested. During the test, the change of the temperature of superheat steam and the furnace temperature were measured. The industrial demonstration test results showed: the NOx removal efficiency may reach at 50% and NOx discharge content may be as lower as 200 mg/nm3 when the heat value of burning coal was about 18MJ/kg (LHV). Some factors, which affected the efficiency of NOx removal, were discussed in this paper.

Experimental Studies on CO2 Absorption in Immersed Hollow Fiber Membrane Contactor

2012 ◽  
Vol 209-211 ◽  
pp. 1571-1575 ◽  
Author(s):  
Xiao Na Wu ◽  
Liang Wang ◽  
Zhao Hui Zhang ◽  
Wen Yang Li ◽  
Xing Fei Guo
Keyword(s):  
Removal Efficiency ◽  
Hollow Fiber ◽  
Flue Gas ◽  
Polyvinylidene Fluoride ◽  
Hollow Fiber Membrane ◽  
Experimental Studies ◽  
Operating Mode ◽  
Membrane Performance ◽  
Membrane Flux ◽  
Absorption Performance

Carbon dioxide (CO2) absorption performance from flue gas was investigated using monoethanolamine (MEA) solution in porous hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes contactor. The influence of operating parameters on CO2 removal efficiency and flux were studied in the immersion operating mode. The experimental results indicated that the CO2 removal efficiency and flux decreased with the increase of flue gas load and carbonization degrees, but the increase of the absorbent concentration and temperature promoted membrane performance of CO2 capture. An increase of 84 m3•m-2•h-1 in the flue gas load resulted in a 68% decrease in the removal efficiency. Absorbent carbonation degree increased to 0.45 mol CO2•mol-1MEA led to the decrease of active ingredient amounts in the absorption solution, and the corresponding removal efficiency and membrane flux dropped by 50% of the initial amounts, respectively. The increase of concentration and temperature of absorbent also benefited membrane absorption performance of CO2 absorption, so that the concentration and temperature of the solvent increased lead to the CO2 removal efficiency and flux increased.

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.

Study on the Experiments of Flue Gas Denitrification and Desulfurization Using Nitric Acid Solution

2008 ◽  
Author(s):  
Bao-Ming Sun ◽  
Shui-E Yin ◽  
Zhong-Li Wang
Keyword(s):  
Nitric Acid ◽  
Oxygen Concentration ◽  
Removal Efficiency ◽  
Flue Gas ◽  
Nitric Acid Concentration ◽  
Nox Removal ◽  
No Removal ◽  
Nox Removal Efficiency ◽  
The Individual ◽  
So2 Concentration

The present study attempts to take nitric acid as absorbent to clean up SO2 and NO gases simultaneously from the simulated flue gas in the lab-scale bubbling reactor, this study was divide into the individual DeNOx experiments and the combined DeSOx/DeNOx experiments: the individual DeNOx experiments were carried out to examine the effect of various operating parameters such as input NO concentration, nitric acid concentration, oxygen concentration input SO2 concentration, adding KMnO4 as additive and taking NaOH as the secondary absorption processes on the SO2 and NOx removal efficiencies at room temperature, the results of the individual DeNOx show that NO removal efficiency of 70%–95% were achieved under optimized conditions. NO removal efficiency increased with the increasing nitric acid concentration and increased by adding KMnO4 into the absorbent as additive as well. The removal efficiency of NO can reach 95% when using the two-step integrated processes of (HNO3+KMnO4)-NaOH, the absorption solution of 50% nitric acid, 400ppm of input NO concentration. 0.5% oxygen concentration and without SO2 in the simulated flue gas. No improvement on the NOx removal efficiency was observed with the increasing of KMnO4 and NaOH concentration in the scrubbing solution. The results of the combined DeSOx/DeNOx experiments show that the maximum DeNOx and DeSOx efficiencies ranged from 36.6% to 81% and from 99.4% to 100.0%, respectively. The prime parameters affecting the NOx removal efficiency are the oxygen concentration and the input SO2 concentration.

Kinetics of DeNOx Process by Ammonia Injection

2011 ◽  
Vol 356-360 ◽  
pp. 2131-2135
Author(s):  
Hai Ping Xiao ◽  
Qin Jian Yu ◽  
Lei Huang
Keyword(s):  
Free Radicals ◽  
Reaction Mechanism ◽  
Removal Efficiency ◽  
Intermediate Product ◽  
Reaction Process ◽  
Nox Removal ◽  
Important Intermediate ◽  
Nox Removal Efficiency ◽  
Kinetics Of ◽  
Ammonia Injection

In order to discover reaction mechanism between ammonia and NOx, reaction process of ammonia and NOx was simulated from the point of kinetics. As a result, NOx removal efficiency was kept in 47.23% ~98.89% at 800°C~1000°C. When NH3/NO was equal or less than 1.5, NOx removal efficiency was enhanced obviously with NH3/NO increasing. NH2 was produced as an important intermediate product in NH3 decomposition. Firstly NH2 was formed in reactions between NH3 and free radicals such as OH, H, O, M. Then NO was directly reduced to N2 by NH2.Therefore, free radicals (especially for NH2, O and H) have important influence on removal efficiency of NOx during ammonia injection.

scholarly journals CO₂ STRIPPING FROM DIETHANOLAMINE USING MEMBRANE CONTACTORS: MODEL VALIDATION AND MEMBRANE WETTABILITY

2019 ◽  
Vol 81 (6) ◽  
Author(s):  
H. N. Mohammed ◽  
Omar S. Lateef ◽  
Ghassan H. Abdullah ◽  
A. L. Ahmad
Keyword(s):  
Liquid Phase ◽  
Flow Rate ◽  
Polyvinylidene Fluoride ◽  
Gas Flow ◽  
Hollow Fiber Membrane ◽  
Operating Conditions ◽  
Co Stripping ◽  
Sweeping Gas ◽  
Membrane Contactors ◽  
The Impact

In the present work, CO2 desorption (stripping) from diethanolamine (DEA) solution using polyvinylidene fluoride hollow fiber membrane contactor is theoretically investigated. A comprehensive two dimensional mathematical model is developed to evaluate the membrane wettability when DEA solution is used at different operating conditions such as sweeping gas flow rate, initial CO2 loading and liquid phase temperature. In addition, the impact of flow rate of liquid phase on the CO2 stripping performance was theoretically investigated. The simulated results were compared with the experimental data obtained from literature. The results revealed that the PVDF membrane was suffered from wetting at studied operating conditions.

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