共查询到20条相似文献,搜索用时 31 毫秒
1.
Richard H. Groth Daniel S. Calabro 《Journal of the Air & Waste Management Association (1995)》2013,63(10):643-645
Several wet chemical methods have been used or suggested for the determination of SO2 concentrations in air pollution work. These include the iron-O-phenanthroline procedure reported by Stephens and Lindstrom, the Scaringelli-modified West-Gaeke method and the Schulze method. This paper describes a laboratory study to evaluate the usefulness of the iron-o-phenanthroline procedure and is directed to individuals concerned with the analysis of gases from the exhaust of gas turbine engines and other combustion processes, including stationary power plants. The variables considered were: range of usefulness in terms of concentration of SO2, efficiency of collection, effect of contaminants, specifically oxides of nitrogen, olefin and aldehyde and effect of storage prior to spectrophctometric measurement. The Stephens-Lindstrom method was found to be suitable for measuring higher levels of SO2 concentrations. It can accurately measure amounts totalling 6000 µl of SO2 and above whereas the other mentioned methods are generally used for lower levels. Collection efficiency was satisfactory. Contaminants, particularly oxides of nitrogen, are a problem only at low levels of SO2. NO2 interference may be eliminated by absorption of the NO2 on Ultraport S impregnated with ANEDA/H2SO4 solution. Temperature control during SO2 addition is necessary. Storage of exposed reagents prior to measurement produce only small errors if stored at 0°C or at room temperature. 相似文献
2.
旋转填料床/柠檬酸盐法吸收-解吸SO2 总被引:1,自引:1,他引:0
提出采用旋转填料床结合柠檬酸盐法脱除烟气中SO2的方法,考察了旋转填料床转子转速、液气比、初始柠檬酸根浓度和初始pH值等因素对脱硫效率的影响。结果表明,采用超重力法超重机转子转速为1 000 r/min、液气比为7L/m3、初始柠檬酸根浓度为1.5 mol/L、吸收液的初始pH值为5.0,脱硫效率稳定在99%左右。研究了水蒸气汽提法解吸SO2时初始柠檬酸根浓度、初始pH值、SO2浓度、富液流量和水蒸气流量对解吸效率的影响,得出了影响SO2解吸率的基本规律,并进行了分析。通过实验证明该方法在技术上是可行的,具有良好的应用前景。 相似文献
3.
《Atmospheric environment(England)》1978,12(1-3):289-293
Interactions between SO2 at low concentrations and carbonaceous particulates have been investigated. The amount of SO2 adsorbed by the solid has been related to its surface area and valued at different compositions of the gaseous mixture in the temperature range 20–150°C. A distinction between two types of adsorption has been made: a part of the adsorbed SO2 is weakly adsorbed, SO2(a) and the residual part is strongly bound to the solid, SO2(b). The fraction of SO2(b) is enhanced by the presence of O2 and H2O. Evolution of SO2(a) to SO2(b) on the solid occurs and its rate appears to be increased by the presence of adsorbed O2 and H2O. By contacting the participate containing SO2 with a flux of air at room temperature, the SO2(a) desorbs into the gaseous stream, but a part of it may be also transformed to SO2(b). 相似文献
4.
G. Van Houte B. Delmon J.C. Maon Ph. Dumont 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1030-1033
This publication concerns the dry removal of SO2 from gases using limestone absorbents. It reports bench-scale experiments made with commercial samples of powdered limestone (CaCO3) activated by addition of a cheap substance, namely CaCl2. The absorption was carried out in a fluidized bed traversed by the flue gases, between 600° and 900° C. The degree and rate of transformation of CaCO3 to CaSO4 in the presence of SO2 and air have been compared for unmodified and modified absorbents. Initial rates of reaction, and the variation of the rate of absorption with time have been measured. The influence of the SO2 content of the gas has been assessed. At 700° C, the maximum degree of transformation of activated limestone to sulfate exceeds 90%, whereas untreated CaCO3 transforms only to 16–20%. At the same temperature, more than 90% of SO2 contained In a gas carrying 0.35% SO2 is removed. Because of the much smaller quantity of solid absorbent required, dry absorption processes based on the modified absorbents might get renewed interest. The modified absorbents might also be used for in situ absorption in fluidized bed combustion, in which the temperatures are in the range studied in the present paper. 相似文献
5.
6.
Chia Hao Hsu Chorng Ming Cho 《Journal of the Air & Waste Management Association (1995)》2013,63(2):246-252
Abstract The removal system for the absorption of CO2 with amines and NH3 is an advanced air pollution control device to reduce greenhouse gas emissions. Absorption of CO2 by amines and NH3 solutions was performed in this study to derive the reaction kinetics. The absorption of CO2 as encountered in flue gases into aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), and NH3 was carried out using a stirred vessel with a plane gas-liquid interface at 50 °C. Various operating parameters were tested to determine the effect of these variables on the absorption kinetics of the reactants in both gas and liquid phases and the effect of competitions between various reactants on the mass-transfer rate. The observed absorption rate increases with increasing gas-liquid concentration, solvent concentration, temperature, and gas flow rate, but changes with the O2 concentration and pH value. The absorption efficiency of MEA is better than that of NH3 and DEA, but the absorption capacity of NH3 is the best. The active energies of the MEA and NH3 with CO2 are 33.19 and 40.09 kJ/mol, respectively. 相似文献
7.
《Journal of the Air & Waste Management Association (1995)》2013,63(4):538-542
Abstract Worldwide concerns about sulfur oxide (SOx) emissions from ships are motivating the replacement of marine residual oil (RO) with cleaner, lower-sulfur fuels, such as marine gas oil (MGO) and marine diesel oil (MDO). Vessel operators can use MGO and MDO directly or blended with RO to achieve environmental and economic objectives. Although expected to be much cleaner in terms of criteria pollutants, these fuels require additional energy in the upstream stages of the fuel cycle (i.e., fuel processing and refining), and thus raise questions about the net impacts on greenhouse gas emissions (primarily carbon dioxide [CO2]) because of production and use. This paper applies the Total Energy and Environmental Analysis for Marine Systems (TEAMS) model to conduct a total fuel cycle analysis of RO, MGO, MDO, and associated blends for a typical container ship. MGO and MDO blends achieve significant (70–85%) SOx emissions reductions compared with RO across a range of fuel quality and refining efficiency assumptions. We estimate CO2 increases of less than 1% using best estimates of fuel quality and refinery efficiency parameters and demonstrate how these results vary based on parameter assumptions. Our analysis suggests that product refining efficiency influences the CO2 tradeoff more than differences in the physical and energy parameters of the alternative fuels, suggesting that modest increases in CO2 could be offset by efficiency improvements at some refineries. Our results help resolve conflicting estimates of greenhouse gas tradeoffs associated with fuel switching and other emissions control policies. 相似文献
8.
Mindong Bai Zhitao Zhang Hong Leng Xiyao Bai Chengwu Yi 《Journal of the Air & Waste Management Association (1995)》2013,63(7):854-860
ABSTRACT This paper presents a technique for the complete, simultaneous decomposition of CO2, SO2, and NOx, as well as the simultaneous removal of fly ash by ultra-high voltage pulse activation. Ultra-high voltage narrow pulse is used to make the gases in the reactor become active molecules, which are then dissociated into nonpoisonous gas molecules and solid particles under the control of a directional reaction model. By using a sufficient charge and a strong electric field, the fly ash can be removed. It becomes the carrier of C and S, and its efficiency is 99.5%. Owing to the action of catalyst B (using Ni as the mother's body), the activation energy of CO2, SO2, and NOx gases is reduced in great magnitude, and their removal efficiency can reach 75~90% at normal pressure and 180 °C. 相似文献
9.
《Atmospheric environment(England)》1985,19(4):637-650
The sensitivity of in-cloud oxidation of SO2 in corrective clouds to a number of chemical and physical parameters is examined. The parameterization of precipitation growth processes is based on the work of Scott (1978) and Hegg (1983). A chemical model predicts gas and aqueous phase distributions of soluble gases and in-cloud uncatalyzed oxidation of SO2 by O3 and H2O2. Sulfate aerosol and SO2, CO2, NH3, H2O2 and O3 gases and their aqueous phase dissociation products are treated.The results indicate that in-cloud conversion is an important removal mechanism for SO2 and accounts for a significant fraction of the precipitation sulfate. However, except at low SO2 concentrations, the precipitation sulfate concentration is insensitive to the initial SO2 concentration; the sulfate concentration is most sensitive to the initial H2O2 and NH3 concentrations. At low SO2 concentrations, the precipitation sulfate concentration is determined primarily by the initial sulfate aerosol concentration. The feedback between sulfate production and pH is important in limiting SO2 oxidation by O3. If gas phase H2O2 of order 1 ppb is the major source of aqueous phase H2O2 for S(IV) oxidation, it is likely that the oxidation reaction is oxidant limited. The sulfate concentration is a decreasing function of the precipitation rate. At low rainfall rates (< 1 mm h−1), ice phase growth decreases the sulfate concentration. However, the results are insensitive to an ice phase origin at moderate and high rainfall rates. 相似文献
10.
Susan Hodgson Fu-Meng Khaw Mark S. Pearce Tanja Pless-Mulloli 《Atmospheric environment (Oxford, England : 1994)》2009,43(21):3356-3363
BackgroundIn the UK air quality has been monitored systematically since 1914, providing valuable data for studies of the long-term trends in air pollution and potentially for studies of health effects of air pollutants. There are, however, challenges in interpreting these data due to changes over time in the number and location of monitored sites, and in monitoring techniques. Particulate matter was measured as deposited matter (DM) using deposit gauge monitors until the 1950s when black smoke (BS) filters were introduced. Estimating long-term exposure to particulates using data from both deposit gauge and BS monitors requires an understanding of the relationships between DM, SO2 and BS.AimsTo explore whether DM and/or SO2, along with seasonal and location specific variables can be used to predict BS levels.MethodsAir quality data were abstracted from hard copies of the monthly Atmospheric Pollution Bulletins for the period April 1956–March 1961 for any sites with co-located DM, SO2 and BS data for three or more consecutive years. The relationships between DM, SO2, and BS were assessed using mixed models.ResultsThere were 34 eligible sites giving 1521 triplets of data. There was a consistent correlation between SO2 and BS at all sites, but the association between DM and BS was less clear and varied by location. Mixed modelling allowing for repeat measurements at each site revealed that SO2, year, rainfall and season of measurement explained 72% of the variability in BS levels.ConclusionsSO2 can be used as a surrogate measure for BS in all monitoring locations. This surrogate can be improved upon by consideration of site specific characteristics, seasonal effects, rainfall and year of measurement. These findings will help in estimating historic, long-term exposure to particulates where BS or other measures are not available. 相似文献
11.
Erhong Duan Dandan Zhang Long Shi Hua Sun Yanan Wang 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1393-1397
ABSTRACT To explore environmentally benign solvents for the absorption of NO and NO2, a series of caprolactam tetrabutyl ammonium halide ionic liquids were synthesized. The solubility of NO and NO2 was measured at temperatures ranging from 298.2 to 363.2 K and atmospheric pressure, and the following trend in the solubility of NO and NO2 in ionic liquids with various halide anions was observed, respectively: F > Br > Cl and Br > Cl > F. Moreover, as the temperature increased from 308.15 to 363.15 K and the mole ratio of caprolactam increased from 2:1 to 6:1, the solubility of NO increased. Alternatively, the solubility of NO2 decreased as the temperature increased from 298.15 to 363.15 K, and the mole ratio of caprolactam increased from 2:1 to 6:1. The absorption and desorption of NO and NO2 was practically reversible in the ionic liquids, which was characterized by nuclear magnetic resonance. The method, which is at least partially reversible, offers interesting possibilities for the removal of NO and NO2.
IMPLICATIONS Basic ionic liquids with amino groups were synthesized and used to capture CO2, SO2, and H2S, and to promote hydrogenation of CO2. In this paper, the authors used caprolactam tetrabutyl ammonium halide ionic liquid (IL) as absorbing medium in which NOx could be absorbed. NOx desorbed from the absorbent could be efficiently reduced by right catalysts at high temperature. The absorbed NO and NO2 gas could be desorbed at higher temperature, allowing the ionic liquids to be reused several times without loss of capability. It was believed that caprolactam tetrabutyl ammonium bromide (CPL-TBAB) ILs may be useful for NOx removal reagent for pollution control. 相似文献
12.
13.
《Atmospheric environment(England)》1981,15(9):1717-1725
Eighty five samples of air particulates collected during the summers of 1975–1977 at three rural and one urban sites in New York State were analyzed for up to 13 elements by instrumental neutron activation analysis. Sixteen samples showed high episodic concentrations of several trace elements and sulfate. SO42−, Cr, Zn, As, Se, Br and Sb were distinctly enriched in these aerosols, relative to their crustal abundances. Sc was used as the reference for the crustal component. Episodic and non-episodic events were statistically indistinguishable if only the means and ranges of elemental concentrations and the enrichment factors were considered. However, correlation matrix and factor analysis showed that while non-episodic cases had inexplicably complex factor loading structures, the structure for episodic cases was simple. Episodic events therefore appear to be better indicators of the sources of non-urban aerosols. Five factors were sufficient to account for 87 % of the total variance in the episodic system. When the dependence of the factors on the set of elements was correlated with the elemental emission patterns of probable sources five sources of the trace elements in these aerosols were identified: distant coal-fired power plants (for SO42−, As. Se), refuse incinerators (for Zn, Sb), iron and steel works (for Cr and possibly Fe, Mn). crustal material (for K, Sc, Mn, Fe) and automotive emissions (for Br). 相似文献
14.
《Atmospheric environment(England)》1978,12(1-3):281-287
One of the most important processes affecting the chemical and physical form of atmospheric sulfur dioxide is the interaction of gaseous SO2 with solid or liquid aerosol particles. The investigation of the catalytic activity of some synthetic aerosols and dust particles of different industrial origin under real atmospheric conditions (i.e. a wide range of relative humidity and temperature) have been investigated in the course of an experimental research program at Karlsruhe Nuclear Research Center, Germany. The experiments were carried out in a 4.5 m3 climate-controlled reaction chamber especially designed for SO2-experiments in the ppm-concentration range. Starting with SO2- concentrations of 3–5 mgm−3 the removal of SO2 from gas phase in the presence of moist aerosol-free air and moist aerosol-polluted air was investigated as was the change of chemical composition of aerosols due to SO2-adsorption and catalytic oxidation. The results of these experiments with synthetic MnSO4 aerosols and fly-ash particles of a hard coal fired power plant are presented. They indicate a strong dependence of the catalytic oxidation rate on the relative humidity but no disappearance of the catalytic activity at low relative humidities. 相似文献
15.
《Atmospheric environment(England)》1978,12(8):1633-1641
The rates of removal of gaseous SO2 over solids commonly found in urban aerosols were measured in the laboratory. A tubular flow reactor, in which the walls of an inner, concentric cylinder were coated with the solid of interest, was used in these studies. Analysis of the data, using models that specifically accounted for mass transport in the laboratory system, yielded collision efficiencies or the fraction of gas-solid collisions that are effective in removing SO2. Experimentally measured collision efficiencies for fresh solid coatings range from < 10−6 to 10−3. Wet chemical and X-ray photoelectron spectroscopic results indicate that, to within an experimental error of a factor of 2, gaseous SO2 is converted to adsorbed sulfate on most of the solids examined.As the time of SO2 exposure increased we found that the rates of SO2 removal gradually diminished until, with prolonged exposure, the solids completely lost their ability to remove this species from the gas phase. The relative humidity of the reaction mixture was found to be important in determining the total amount, but not the initial rate, of SO2 uptake, with SO2 uptake increasing at higher humidities. Overall, selected solids removed up to several tenths of a gram of SO2 per gram solid from humidified reaction mixtures. Further reaction could be induced by exposure to small amounts of ammonia.The saturation type of behavior observed on prolonged exposure to SO2 led to the suspicion that fly ash materials examined in this study, as received, may already have undergone substantial reaction with SO2, before or during collection. Further experiments on these materials, involving washing those as received materials with distilled water to remove soluble sulfates, supported this contention. Of the six fly ash materials examined, initial collision efficiencies for four of these materials were increased by factors ranging from 2 to > 300 by the water pretreatment. The other two materials exhibited high initial collision efficiencies (~10−4) that were unaffected, to within experimental error, by the water washing.Atmospheric projection of results from this study suggests that freshly emitted aerosols can be quite effective in converting gaseous SO2 to particulate sulfate. The capacity limited nature of the reactions suggests that these processes will be most important at or near emission sources, although further, non-source interactions can be induced by atmospheric ammonia. 相似文献
16.
Sergio F. Galeano Thomas W. Tucker Leyondis Duncan 《Journal of the Air & Waste Management Association (1995)》2013,63(10):790-793
The body of information presented in this paper is directed to the operating personnel and process engineers employed in the power and recovery departments of a chemical pulping operation. The proper evaluation of the total analytical and sampling system (TASS), to be used in the determination of sulfur oxides is as important as a proper analytical and recording system (ARS). The presence of other sulfur gaseous compounds and particulates could greatly influence the results of the determination. The analytical method employed determines sulfur dioxide and trioxide from an aliquot of the trapping solution, 3% hydrogen peroxide and 8 0% isopropyl alcohol respectively. The aliquot is titrated with barium perchlorate in the presence of Thorin indicator. The results of evaluating the method indicated negligible interference from the presence of hydrogen sulfide, mercaptans and nitrogen oxides. A blank correction of 15 parts per million (ppm) is recommended whenever 100 ppm of hydrogen sulfide or more are simultaneously present in the gas stream. Particulaies are shown to interfere either by addition or subtraction. Sulfate particulates that will add to the determination must be removed, but in doing so, care must be exerted to avoid surface-contacting conditions that promote reaction between carbonates and the sulfur oxides. The integrated method of sampling and analysis will permit determinations from a flue gas with sulfur oxides concentrations of 30 ppm and above. The relative standard deviation improves from 10% at 100 ppm SO2 to 2.6% at 1000 ppm SO2. In both cases, sulfides were present. 相似文献
17.
Hideo Okabe Paul L. Splitstone Joseph J. Ball 《Journal of the Air & Waste Management Association (1995)》2013,63(6):514-516
The principle of this detector is based on the measurement of the intensity of the ultraviolet fluorescence of SO2 produced by absorption of the Zn 2138 Å or Cd 2288 Å line. The fluorescence intensity was found to be linear from 0.1 to 500 ppm of SO2 in air with the Zn lamp and from 0.1 to 1600 ppm with the Cd lamp. The detection limit at present is about 20 ppb. There is no detectable interference from O3, H2S, NO2, CO2, CO, or H2, although the presence of a large concentration of CS2 (500 times as much as SO2) NO (500 times) or C2H4 (4000 times) interferes with the measurement. The presence of 2% H20 reduces the signal by 25%, while up to 1 % CH4 has almost no effect. 相似文献
18.
Constance L. Senior William Morris Thomas A. Lewandowski 《Journal of the Air & Waste Management Association (1995)》2013,63(7):832-843
Oxyfuel combustion is a promising technology that may greatly facilitate carbon capture and sequestration by increasing the relative CO2 content of the combustion emission stream. However, the potential effect of enhanced oxygen combustion conditions on emissions of criteria and hazardous air pollutants (e.g., acid gases, particulates, metals and organics) is not well studied. It is possible that combustion under oxyfuel conditions could produce emissions posing different risks than those currently being managed by the power industry (e.g., by changing the valence state of metals). The data available for addressing these concerns are quite limited and are typically derived from laboratory-scale or pilot-scale tests. A review of the available data does suggest that oxyfuel combustion may decrease the air emissions of some pollutants (e.g., SO2, NOx, particulates) whereas data for other pollutants are too limited to draw any conclusions. The oxy-combustion systems that have been proposed to date do not have a conventional “stack” and combustion flue gas is treated in such a way that solid or liquid waste streams are the major outputs. Use of this technology will therefore shift emissions from air to solid or liquid waste streams, but the risk management implications of this potential change have yet to be assessed. Truly useful studies of the potential effects of oxyfuel combustion on power plant emissions will require construction of integrated systems containing a combustion system coupled to a CO2 processing unit. Sampling and analysis to assess potential emission effects should be an essential part of integrated system tests. Implications: Oxyfuel combustion may facilitate carbon capture and sequestration by increasing the relative CO2 content of the combustion emission stream. However, the potential effect of enhanced oxygen combustion conditions on emissions of criteria and hazardous air pollutants has not been well studied. Combustion under oxyfuel conditions could produce emissions posing different risks than those currently being managed by the power industry. Therefore, before moving further with oxyfuel combustion as a new technology, it is appropriate to summarize the current understanding of potential emissions risk and to identify data gaps as priorities for future research. 相似文献
19.
Lidia Lombardi Giulia Costa Riccardo Spagnuolo 《Environmental science and pollution research international》2018,25(36):35855-35865
In this work, ash generated by the combustion of wood in a central heating plant was used to remove and permanently store by accelerated carbonation CO2 contained in a gas mixture simulating biogas. The process was studied as an alternative treatment to the ones currently available on the market for biogas upgrading. The process was investigated at laboratory scale by setting up a facility for directly contacting the wood ash and the synthetic biogas in a fixed bed reactor. The process was able to completely remove CO2 during its initial phase. After about 30 h, CO2 started to appear again in the outlet stream and its concentration rapidly increased. The specific CO2 uptake achieved in solid carbonate form was of about 200 g/kg of dry wood ash. This value is an order of magnitude higher than the ones found for waste incineration bottom ash carrying out similar experiments. The difference was ascribed to the physicochemical properties of the ash, characterized by a fine particle size (d50 <?0.2 mm) and high content of reactive phases with CO2 (e.g., Ca hydroxides). The leaching behavior of the wood ash was examined before and after the accelerated carbonation process showing that the release of several elements was lower after the treatment; Ba leaching in particular decreased by over two orders of magnitude. However, the release of the critical elements for the management of this type of residues (especially Cr and sulfates) appeared not to be significantly affected, while V leaching increased. 相似文献
20.
Joris Koornneef Andrea Ramirez Toon van Harmelen Arjan van Horssen Wim Turkenburg Andre Faaij 《Atmospheric environment (Oxford, England : 1994)》2010,44(11):1369-1385
This study quantifies the trade-offs and synergies between climate and air quality policy objectives for the European power and heat (P&H) sector. An overview is presented of the expected performance data of CO2 capture systems implemented at P&H plants, and the expected emission of key air pollutants, being: SO2, NOX, NH3, volatile organic compounds (VOCs) and particulate matter (PM). The CO2 capture systems investigated include: post-combustion, oxyfuel combustion and pre-combustion capture.For all capture systems it was found that SO2, NOx and PM emissions are expected to be reduced or remain equal per unit of primary energy input compared to power plants without CO2 capture. Increase in primary energy input as a result of the energy penalty for CO2 capture may for some technologies and substances result in a net increase of emissions per kWh output. The emission of ammonia may increase by a factor of up to 45 per unit of primary energy input for post-combustion technologies. No data are available about the emission of VOCs from CO2 capture technologies.A simple model was developed and applied to analyse the impact of CO2 capture in the European P&H sector on the emission level of key air pollutants in 2030. Four scenarios were developed: one without CO2 capture and three with one dominantly implemented CO2 capture system, varying between: post-combustion, oxyfuel combustion and pre-combustion.The results showed a reduction in GHG emissions for the scenarios with CO2 capture compared to the baseline scenario between 12% and 20% in the EU 27 region in 2030. NOx emissions were 15% higher in the P&H sector in a scenario with predominantly post-combustion and lower when oxyfuel combustion (?16%) or pre-combustion (?20%) were implemented on a large scale. Large scale implementation of the post-combustion technology in 2030 may also result in significantly higher, i.e. increase by a factor of 28, NH3 emissions compared to scenarios with other CO2 capture options or without capture. SO2 emissions were very low for all scenarios that include large scale implementation of CO2 capture in 2030, i.e. a reduction varying between 27% and 41%. Particulate Matter emissions were found to be lower in the scenarios with CO2 capture. The scenario with implementation of the oxyfuel technology showed the lowest PM emissions followed by the scenario with a significant share allocated to pre-combustion, respectively ?59% and ?31%. The scenario with post-combustion capture resulted in PM emissions varying between 35% reduction and 26% increase. 相似文献