Simultaneous Removal Of SO2 Research Articles

Simultaneous Removal of SO2, NO, and CO2 on Metal-Modified Coconut Shell Activated Carbon

Simultaneous removal of SO2, NO, and CO2 from simulate flue gas was examined in this study. The sorbents were prepared by coconut shell activated carbon (SAC) and impregnated with metal nitrates (Cu, Ca, Mg, Zn). The adsorptive performance of sorbents was studied. The performances of these sorbents were not in agreement on adsorption of SO2, NO, and CO2. Cu-SAC seemed to be a promising sorbent through the calculation of adsorption capacity. Effect of different feed gases on adsorption activity of Cu-SAC was also studied. It indicates that CO2 impacts the adsorption of SO2 and NO but limited. O2 is the key to co-adsorption as its good oxidation capacity. The adsorbed SO2 and NO can interact with each other so as to form intermediate species under the influence of O2, which facilitates SO2 and NO oxidized to SO3 and NO2, respectively.

Computational screening of porous metal‐organic frameworks and zeolites for the removal of SO2 and NOx from flue gases

Sulfur oxides (SO2) and nitrogen oxides (NOx) are principal pollutants in the atmosphere due to their harmful impact on human health and environment. We use molecular simulations to study different adsorbents to remove SO2 and NOx from flue gases. Twelve representative porous materials were selected as possible candidates, including metal‐organic frameworks, zeolitic imidazolate frameworks, and all‐silica zeolites. Grand canonical Monte Carlo simulations were performed to predict the (mixture) adsorption isotherms to evaluate these selected materials. Both Cu‐BTC and MIL‐47 were identified to perform best for the removal of SO2 from the flue gases mixture. For the removal of NOx, Cu‐BTC was shown to be the best adsorbent. Additionally, concerning the simultaneous removal of SO2, NOx, and CO2, Mg‐MOF‐74 gave the best performance. The results and insights obtained may be helpful to the adsorbents selection in the separation of SO2 and NOx and carbon capture. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2314–2323, 2014

Simultaneous removal of SO2, NO and Hg0 from flue gas by ferrate (VI) solution

Simultaneously removing SO2, NO and Hg0 from flue gas was examined by ferrate (VI) solution at a bubbling reactor. The removal efficiencies of 100% for SO2, 64.8% for NO and 81.4% for Hg0 were achieved respectively, under the optimum experimental conditions, in which concentration of ferrate (VI) solution was 0.25 mmol/L, solution pH was 8.0, flue gas flow rate was 1 L/min and reaction temperature was 320 K. Based on the discussions of the ferrate (VI) solution characteristics, the comparisons of the standard electrode potential (E0) of ferrate (VI) solution with E0 values of reactant, and the analysis of the reaction products, a mechanism of simultaneous removal was proposed. In the process of simultaneous removal, FeO42− and HFeO4− as the dominant species of ferrate (VI), could rapidly oxidize SO2, NO, and Hg0 into SO42−, NO3− and Hg2+.

Simultaneous Removal of SO2 and NOX by Wet Scrubbing Using NaOH Solutions

Simultaneous Removal of SO2 and NOX by Wet Scrubbing Using NaOH Solutions

Simultaneous removal of SO2 and NO2 using a Mg–Al oxide slurry treatment

SO2 and NO2 were simultaneously removed from a mixed gas using a Mg–Al oxide slurry treatment. Both adsorption to the oxide material itself and dissolution of the gases in the aqueous slurry contributed to the removal. A comparison was made between removal of the two gases separately and the simultaneous process. The removal of SO2 using both the simultaneous and individual process was similar; however, the removal of NO2 was lower for the simultaneous process. For the individual treatments, SO2 and NO2 were separately dissolved in the Mg–Al oxide slurry to produce SO32-, NO2-, and NO3-, which were subsequently removed by the Mg–Al oxide. However, when the simultaneous process was employed, the dissolved gases were seen to have a significant effect on each other. It was speculated that the production of NO2- was increased by the reduction of NO2 by SO32-. On increasing the quantity of the Mg–Al oxide, or on raising the temperature of the system, the removal of SO2 increased, with a concurrent decrease in NO2 removal. The increase in removal of SO32- was speculated to hinder the conversion of NO2 to NO2-, therefore decreasing the removal of the nitrogen species. The results demonstrate that the Mg–Al oxide slurry was highly effective for simultaneously removing NO2 and SO2 from a mixed gas.

Simultaneous removal of SO2 and NO X with ammonia absorbent in a packed column

Catalytic oxidation of NO followed by simultaneous removal of SO2 and NO X with ammonia is a promising method for control of coal-fired flue gas pollutants. We investigated simultaneous absorption of SO2 and NO X in a packed column with ammonia, and found that SO2 and NO X could promote absorption with each other in the process of simultaneous removal SO2 and NO X . The removal efficiency of SO2 and NO X was, respectively, about 98% and 70.9% at pH 5.5, temperature 323.15 K, SO2 concentration 1,800×10−6, NO X concentration 400×10−6 and $${{m_{NO_2 } } \mathord{\left/ {\vphantom {{m_{NO_2 } } {m_{NO} }}} \right. \kern-\nulldelimiterspace} {m_{NO} }}$$ in our experimental system. The experimental results also show that the formation of sulfite oxidized by reacting with dissolved NO2 and the molar ratio of sulfite to total sulfur is more than 0.8 in the solution. Accordingly, the energy consumption for sulfite oxidation would be greatly reduced in the process of simultaneous desulfurization and denitrification with ammonia.

Effect of operating conditions towards simultaneous removal of SO2 and NO using copper modified rice husk ash: Role as sorbent and catalyst

Simultaneous removal of SO2 and NO from flue gas can be a potential and breakthrough solution to reduce the capital and operating cost of air pollutants control technology, making it more economically feasible. In this study, copper based RHA sorbent was used to adsorb SO2 and NO simultaneously. Effect of operating temperature, concentrations of SO2 and NO towards sorbent sorption activity was studied. The findings from this study revealed that there is no clear trend on the effect of temperature but optimum operating temperature of 100°C was determined to favour both desulfurization and denitrification process. In addition, optimum SO2 and NO concentration were determined as 2000ppm and 500ppm, respectively. Although the optimum operating conditions were determined based on the total mols of pollutants removed by the sorbent but the on-going removal activity by the sorbent during equilibrium stage was not neglected. Optimum adsorption capacity for the derived sorbent was 53.40mgSO2/g sorbent and 6.90mgNO/g sorbent. Characterizations were performed on spent sorbent to identify the various products of desulfurization and denitrification activity. This study revealed that the synthesized sorbent does not solely act as a sorbent but also as a catalyst.

Interactive Effect for Simultaneous Removal of SO2, NO, and CO2 in Flue Gas on Ion Exchanged Zeolites

A purification system for simultaneous removal of SO2, NO, and CO2 in flue gas was considered in this study. For improving the purification performance of candidate adsorbent NaX zeolite, ion exchange experiments were conducted with cation K+, Ca2+, Mn2+, and Co2+, respectively. The texture properties of series zeolites were examined by N2 porosimetry, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. Among the sorbents investigated, K–NaX zeolite exhibited the best result to remove SO2, NO, and CO2 all together. XPS results revealed that SO2 has been oxidized to form SO42– on the solid surface; however, species N and C have not been observed. In order to understand the coadsorption effects, pure component, binary, ternary components, and mimic flue gas breakthrough experiments were designed and carried out. It suggested that SO2 and NO was bonded on the adsorbent surface with degradation of NO. A little competitive effect of CO2 on SO2 and NO adsorption system were found. Finally, monitoring of coadsorption venting gas, thermodynamic equilibrium species simulation, TPD experiment, and quantum chemical calculation technology were used to examine the interactive effect.

Flue Gas Ammonia Simultaneous Removal of SO<sub>2</sub> and NO<sub>x</sub> Technology and Development

The principle and technical characteristics of flue gas simultaneous removal of SO2 and NOx technology are expounded. The application and research progresses about this field are introduced. Besides that, the major research directions of flue gas ammonia combined desulphurization and denitration technology are prospected.

Simultaneous Removal of SO<sub>x</sub> and NO<sub>x</sub> in Flue Gas at Power Stations over a Cu/Na-13X Zeolite Catalyst

Due to their significant impacts on the environment and health, there has been a growing environmental concern on sulfur oxide (SOx), nitrogen oxides (NOx) emissions to the atmosphere in the past two decades. Flue gas at coal-fired power stations is one of the main sources for the emissions of SOxand NOx. More and more stringent regulations on the emission of these pollutants come in force, which have put a high pressure on coal-fired power generators. Cost-effective and sustainable technologies for the reduction of such pollutants from flue gas have become increasingly important nowadays. However, even though numerous attempts have been made aiming at developing technologies for the removal of SOxand NOx, not much effort has been made on the simultaneous conversion of NOxand SOxin flue gas via selective catalytic reduction. This paper presents the study of simultaneous removal of SO2and NO over a synthesized Cu/Na-13X zeolite catalyst using carbon monoxide as a reducing agent. The characterization of fresh and spent catalysts was carried out using X-Ray Diffraction (XRD) and Brunauer-Emmett-Teller (BET) Surface Area Analyser. The experiments on the selective reduction of SO2and NO were carried out using a multi-functional catalyst testing rig with an online flue gas analyser. It has been found that zeolite has a good capability of SO2adsorption even under elevated temperatures. The removal efficiency was found to be 100% for SO2and 89% for NO over a Cu/Na-13X zeolite catalyst.

Simultaneous Removal of SO<sub>2</sub> and NO with Activated Carbon from Sewage Sludge Modified by Chitosan

The simultaneous removal of SO2 and NO was investigated with the activated carbon from sewage sludge (referred as ACS) modified by chitosan (referred as CS).The effects of CS loading and operating conditions on the simultaneous removal of SO2 and NO were analyzed. The results indicate that compared with the ACS, impregnating CS results in significant increase in SO2 or NO removal. Relative humidity enhances SO2 adsorption capacities, but not for NO. The SO2 adsorption capacities of the CS / ACS show no obvious decrease at small amount of NO in the feed. However, higher amounts of NO reduce the SO2 adsorption capacities. The opposite phenomenon appears for NO when a small amount of SO2. So a competitive sorption consists between NO and SO2. Simultaneous adsorptions for NO and SO2 is due to more active sites from CS.

Development of Catalyst-Sorbents for Simultaneous Removal of SO2 From Flue Gas by Low Temperature Ozone Oxidation

One technological process employing ozone and heterogeneous catalyst-sorbents was proposed for removal of SO2 from flue gas. The catalyst-sorbents were developed and tested especially for adsorption and oxidation of SO2. Alternative catalyst-supporters including γ-Al2O3, permutite, silica gel, activated carbon and diatomite combined with different metal oxides (MnO2, Cr2O3, Fe2O3, CuO, CoO and NiO) were evaluated and tested. It was found that γ-Al2O3 doped with MnO2 can be considered as removal-effective sorbent for adsorption and oxidation of SO2. The synergetic effect between ozone and catalyst was found to be dominated. Effects of catalyst preparation parameters like calcination temperature, metal loaded and reaction temperature, etc. were investigated based on the MnO2/Al2O3 catalyst-sorbents. Results show that γ-Al2O3 combined with 8% Mn, calcinated under 573 K and reacted at 413 K are the optimal parameters for removal of SO2. Extra NO in flue gas can slightly enhance the capture efficiency of SO2.

Simultaneous removal of SO2, NO and mercury using TiO2-aluminum silicate fiber by photocatalysis

A novel TiO2-aluminum silicate fiber (TAS) nanocomposite, synthesized by a sol–gel method, is proposed to use as a photocatalyst for the removal of multiple pollutants. The photocatalyst has been characterized by XRD, SEM, EDX, UV–Vis spectra and BET. The TAS calcined at 500°C exhibited the biggest BET surface area and highest photocatalytic activity and was used as the photocatalyst for subsequent experiments. The oxidation and removal efficiencies of SO2, NO and elemental mercury (Hg0) in simulated coal combustion flue gas by the TAS catalyst were tested under UV irradiation. Experiments were conducted in a fixed-bed reactor at temperatures ranging from 30 to 120°C. In simulated flue gas (4% O2, 12% CO2, 2% H2O, 400ppm SO2, 50ppm NO), the removal efficiencies for SO2, NO and Hg0 at 120°C and with UV intensity of 3mWcm−2 can reach 33%, 31% and 80%, respectively. NO inhibited SO2 oxidation due to its competition for active adsorption sites. SO2 also had a prohibitive effect on NO removal. In contrast, SO2 was found to have a promotional effect on Hg0 oxidation due to the formation of HgSO4. NO inhibited the photocatalytic removal of mercury. During the simultaneous removal of SO2, NO and Hg0 on TAS, the photocatalytic oxidation efficiency decreased from 30 to 120°C. O2 exhibited a promotional effect on the photocatalytic oxidation due to the formation of lattice oxygen. However, the addition of water vapor to the simulated flue gas inhibited the oxidation of SO2, NO and Hg0. The UV intensity was the most important factor in the photocatalytic oxidation. Our discussion on the possible reaction mechanism provides some useful information for developing effective photocatalysts to oxidize SO2, NO and Hg0 in simulated coal combustion flue gas.

Regeneration of hexamminecobalt(II) under the catalysis of activated carbon modified with ZnCl2 solution

The simultaneous scrubbing of NO and SO2 can be accomplished by hexamminecobalt(II) solution. Activated carbon acts as a catalyst to regenerate hexamminecobalt(II), Co(NH3)62+, to sustain the NO removal efficiency. In this paper, ZnCl2 solution has been used to ameliorate the catalytic performance of coconut activated carbon in the regeneration of Co(NH3)62+. The effects of the modification condition on the catalytic performance of activated carbon have been investigated in a batch stirred cell. The change of the surface chemical characteristics of the activated carbon caused by ZnCl2 treatment was measured by determining the concentrations of acidic and basic groups as well as their points of zero charge (pHpzc) with Boehm titration and mass titration. The alteration of the surface physical characteristics of the carbons was determined with an ASAP2000 Surface Analyzer using N2 as the adsorbate. The experiments demonstrate that the catalytic performance of the coconut activated carbon may be improved when the carbon is treated by ZnCl2 solution with concentration above 0.30moll−1. The best ZnCl2 concentration may be 0.50moll−1. The optimal impregnation duration is 9h. High activation temperature is propitious for the amelioration of the catalytic capability of carbon. 4h may be the best time for the activation of activated carbon. In our experiment, the NO removal efficiency is maintained at a level of 73% when the regeneration of Co(NH3)62+ is under the catalysis of modified carbon while that is 57% with the regeneration of Co(NH3)62+ catalyzed by original carbon. It can be concluded that such modification can improve the catalytic performance of coconut activated carbon in the simultaneous removal of SO2 and NO with Co(NH3)62+ ammonia solution.

Experimental studies on simultaneous removal of CO2 and SO2 in a polypropylene hollow fiber membrane contactor

Membrane gas absorption technology is a promising alternative to conventional technologies for the mitigation of acid gases. In this study, simultaneous removal of SO2 and CO2 from coal-fired flue gas was carried out in a polypropylene hollow fiber membrane contactor using aqueous monoethanolamine as the absorbent. The influences of liquid and gas flow rates on the simultaneous absorption performance of CO2 and SO2 were investigated. The experimental results indicated that the membrane contactor could eliminate these two sour gases simultaneously and effectively. Absorption of SO2 and CO2 was enhanced by the increase in liquid flow rate and decrease in gas flow rate. It was observed that a small amount of SO2 in the flue gas had a slight influence on the absorption of CO2. In addition, the membrane contactor was operated continuously for two weeks to evaluate its duration performance. The results showed that the CO2 mass transfer rate was decreased significantly with the operating time due to partial wetting of membrane pores. After 14days of continuous operation, the CO2 mass transfer rate of the wetted membrane contactor was decreased by 41% but could be retrieved to 86% of the fresh one by increasing the gas phase pressure.

Effect of solution pH on SO2, NOx, and Hg removal from simulated coal combustion flue gas in an oxidant-enhanced wet scrubber

This paper presents a study on the simultaneous removal of SO2, NOx and Hg (both Hg0 and Hg2+) from a simulated flue gas by oxidant injection in a bench-simulated wet limestone scrubber for a wide range of slurry pH. The slurry pH strongly influenced the chemical mechanism in the scrubber and, therefore, affected pollutant removal. This paper also examines the potential ClO2(gas) reemission from a developed multipollutant scrubber at different slurry pHs. To better understand the chemical mechanisms at each slurry pH and to apply a mass balance to the process, detailed product ion analyses were performed for all experiments. Ion analysis covered three different chlorine species (chlorite, chloride, chlorate), sulfate, nitrite and nitrate. Different NOx removal efficiencies and mechanisms were found in acidic and alkaline pHs in the multipollutant scrubber. The acidic solution was favorable for NO and Hg0 oxidation, but increasing the slurry pH above 7.0 was disadvantageous for NO and Hg oxidation/removal. However, the rate of NOx absorption (by percentage) was higher for the alkaline solution. Implications This paper demonstrated a method for controlling multipollutant (SO2, NOx, Hg) emissions from a gas stream of a stationary combustion source in a wet limestone wet-FGD scrubber enhanced by an oxidizing additive. This paper explores how the flue gas conditions, especially the slurry pH, affect the chemical mechanisms of the multipollutant process and the pollutant removal efficiencies. The pH may be important when considering the location of oxidant injection into the scrubber/channel, where local parameters such as pH strongly vary. The usage of chlorite additive is potentially threatens ClO2(gas) emission; therefore, research in this area was also presented in this paper.

Simulation of Simultaneous Removal of SO2 and NO Using Pulsed Discharge

AbstractIn order to provide the basis to efficiently reduce the energy consumption and improve the removal rate, the simultaneous removal processes of SO

Simultaneous Removal of SO2 and NO from Flue Gas Using Multicomposite Active Absorbent

A multicomposite active absorbent was prepared using the liquid-phase complex of NaClO2 and NaClO as well as solid-phase slake lime to simultaneous desulfurization and denitrification at a flue gas circulating fluidized bed (CFB). The effects of influencing factors on the removal efficiencies of SO2 and NO were investigated. Removal efficiencies of 96.5% for SO2 and 73.5% for NO were obtained, respectively, under the optimal experimental conditions. The characterization of the spent absorbent was carried out by using energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and chemical analysis methods, from which the simultaneous removal mechanism of SO2 and NO based on this absorbent was proposed.

Kinetics of the [Fe(III)-EDTA]− Reduction by Sulfite under the Catalysis of Activated Carbon

The simultaneous removal of SO2 and NO from the flue gases with the [Fe(II)-EDTA]2– solution has not been put into commercial application because of the quick oxidation of [Fe(II)-EDTA]2– to [Fe(II...

Simultaneous Removal of SO2 and NO2 on α-Al2O3 Absorbents Loaded with Sodium Humate and Ammonia Water

Simultaneous removal of sulfur dioxide (SO2) and nitrogen dioxide (NO2) from simulated flue gas has been investigated with absorbents, which are made of α-Al2O3 impregnated with sodium humate and ammonia water solution. The results of the experiment showed that 100% of SO2 and about 80% of NO2 in simulated flue gas could be removed in a fixed-bed reactor, which is packed with these absorbents. The property of preferential absorption of SO2 is obvious when we used these absorbents to remove SO2 and NO2 at the same time from simulated flue gas. The products of this process were characterized by Fourier transform infrared spectroscopy and X-ray diffraction. It can be concluded that the reaction products are mainly ammonium sulfate, ammonium sulfite [(NH4)2SO3], ammonium nitrate (NH4NO3), ammonium nitrite (NH4NO2), and humic acid in this process. The content of NH4NO3 takes a little part of the products as well as NH4NO2 and (NH4)2SO3. This product can be used for compound fertilizer.