Particles In Flue Gas Research Articles

Влияние осажденных частиц дымовых газов на триботехнические и виброакусти-ческие характеристики полимерных композитов

Влияние осажденных частиц дымовых газов на триботехнические и виброакусти-ческие характеристики полимерных композитов

Design and analysis of a novel furnace throat for removing dust particles in flue gas emitted from copper smelting furnace by a computational method.

A novel furnace throat structure was designed to reduce dust particle concentration in the flue gas emitted from the copper smelting industry. A two-stage turbulence model of the furnace throat based on the RNG k-ε model combined with the stochastic trajectory model was developed to analyze the gas flow and particle trajectories in this furnace throat structure. The resulting turbulent flow fields and particle trajectories under different operating conditions were shown and discussed. It indicates that the furnace throat plays an important role in separating the dust particles from the flue gas by applying centrifugal force and subsequent resistance force. Moreover, the effects of the radius of the inner flue, the number of the spiral plate, and the number of the spiral plate turns on the particle collection efficiency were analyzed to optimize the throat structure. The simulation results show that the furnace throat with inner flue radius of 0.05 m, two spiral plates, and two spiral plate turns has the highest particle collection efficiency. Furthermore, a series of experimental tests were conducted to validate the accuracy of the simulation results, and the measured experimental data show a good correlation with the numerical results.

Emissions from a fast-pyrolysis bio-oil fired boiler: Comparison of health-related characteristics of emissions from bio-oil, fossil oil and wood

There is currently great interest in replacing fossil-oil with renewable fuels in energy production. Fast pyrolysis bio-oil (FPBO) made of lignocellulosic biomass is one such alternative to replace fossil oil, such as heavy fuel oil (HFO), in energy boilers. However, it is not known how this fuel change will alter the quantity and quality of emissions affecting human health. In this work, particulate emissions from a real-scale commercially operated FPBO boiler plant are characterized, including extensive physico-chemical and toxicological analyses. These are then compared to emission characteristics of heavy fuel-oil and wood fired boilers. Finally, the effects of the fuel choice on the emissions, their potential health effects and the requirements for flue gas cleaning in small-to medium-sized boiler units are discussed.The total suspended particulate matter and fine particulate matter (PM1) concentrations in FPBO boiler flue gases before filtration were higher than in HFO boilers and lower or on a level similar to wood-fired grate boilers. FPBO particles consisted mainly of ash species and contained less polycyclic aromatic hydrocarbons (PAH) and heavy metals than had previously been measured from HFO combustion. This feature was clearly reflected in the toxicological properties of FPBO particle emissions, which showed less acute toxicity effects on the cell line than HFO combustion particles. The electrostatic precipitator used in the boiler plant efficiently removed flue gas particles of all sizes. Only minor differences in the toxicological properties of particles upstream and downstream of the electrostatic precipitator were observed, when the same particulate mass from both situations was given to the cells.

An Insight into Electrostatic Field Effects on SO3 Adsorption by CaO with CO2, SO2 and H2O: A DFT Approach

ABSTRACT Because of the compulsory installation of electrostatic precipitators in coal-fired power plants, SO3 and particles in flue gas inevitably pass through areas with electric field and electric charge distributed. CaO is the highest alkaline content in fly ash and has strong interactions with SO3. Therefore, it is important to understand the effects of the electric field on the binding energies of SO3 and CaO. Density functional theory calculations were applied to examine the electrostatic field dependence of SO3 adsorption on the CaO(100) surface. The energetic, geometric and electronic nature of the modeled systems was analyzed. Trends of the adsorption energy variation in a positive or negative electrostatic field presented great differences. When the electrostatic field was small, it was observed that the required adsorption energy was reduced regardless of the positive or negative electrostatic field. With increased electrostatic field strength, the adsorption energy showed an increasing trend in a positive field, while the adsorption energy decreased in a negative field. The positive field enhanced the charge density changes of the surface O across the Ca around the OCaO, while the negative field enhanced the change of the charge density of the Ca below the OCaO. The SO42–-like structure accumulated electrons as a unit and the charge transfer of the SO42– increased with the incremental adsorption energy in a linear relationship. On the H pre-adsorbed surface, the total increment was much smaller than in previous cases in a positive field, and the total variation was negligible in a negative field.

Fractal Reconstruction of Microscopic Rough Surface for Soot Layer during Ceramic Filtration Based On Weierstrass–Mandelbrot Function

The microscopic surface of soot layer on the external surface of filtration elements is rather hard to reconstruct. In this study, an incinerator–filter setup was designed to mimic the capture of soot particles in flue gas to achieve the samples to construct the rough soot-layer surface. The specific velocities around the ceramic cartridge were determined by particle image velocimetry (PIV) measurement. Resorting to a box-counting method, the fractal dimensions (FDs) were determined by Richardson–Mandelbrot method with binary images of samples. Accordingly, the in situ thickness of soot layer was constructed with consideration of particle deposit and the microscopic rough surfaces were modeled by employing Weierstrass–Mandelbrot (W-M) function. Additionally, a comparison between the constructed surface and real surface achieved from the image taken by atomic force microscopy (AFM) was performed. The results suggest that all roughness deviations of constructed surface from real surface of soot layer not ex...

Emission Characteristics of Fine Particles from Wet Flue Gas Desulfurization System Using a Cascade of Double Towers

The removal of fine particles from coal-fired flue gas using chemical and physical reactions was investigated experimentally in a wet flue gas desulfurization (WFGD) system with a cascade of double-towers system. The flue gas particles were collected by an Andersen 8-stage impactor, and their mass concentration and particle size distribution were investigated. Based on analysis via scanning electron microscopy/energy dispersive X-ray spectrometry (SEM-EDX), X-ray diffraction (XRD) and inductively coupled plasma atomic emission spectrometry (ICP-AES), the morphological characteristics and the major and minor-element concentrations of particles were studied. The results indicate that the size distribution of fly ash particles at the inlet of the WFGD system was typically distributed bimodally. Although a bimodal distribution was still observed after the desulfurization, all the peaks had decreased. Furthermore, the content of S and Ca increased. Fine particles in the flue gas consisted of about 26.48% limestone and 41.19% gypsum particulate matter, eventually forming the Ca11.3Al14O32.3 crystal. The net removal efficiency of the double tower WFGD system reached 84.16% for the original particles, which was similar to that of the conventional single tower system. The entrainment of recirculated slurry contributed to the submicron particle emissions, and the total removal efficiency of the double tower WFGD system decreased to 51.1%.

Relationship between the zeta potential and the chemical agglomeration efficiency of fine particles in flue gas during coal combustion

Fly ash fine particles emitted from flue gas during coal combustion are the primary atmospheric pollutants in China. The purpose of this study was to investigate the characteristics of the zeta potential of fine particle suspensions. The relationship between the zeta potential and the fine particle removal efficiency was also discussed. Batch experiments were conducted to evaluate the zeta potential of fine particle aqueous solutions under various pH, ion concentration, surfactant, polymer, and chemical agglomeration solution conditions. A chemical agglomeration system was designed to simulate the removal process of the fine particles. The test results indicated that the zeta potential absolute value of the solution decreased initially and then increased as the pH increased. As the pH increased from 4 to 12, the zeta potential decreased from Zp = 9.4 mV to Zp = −45.4 mV. The isoelectric point (IEP) was 4.3. Also at the IEP, the highest fine particle removal efficiency of 25.9% was achieved. The zeta potential increased as the metal cation concentration of the solutions increased. The trivalent cation Al3+ exhibited the best performance, which increased Zp from −32.1 mV to −11.2 mV and produced the highest fine particle removal efficiency of 9.2%. Polymers significantly impacted the zeta potential. As the concentration of kappa-carrageenan (CAR) increased from 0.01% to 5%, the zeta potential increased from −30.1 mV to 12.6 mV. The highest fine particle removal efficiency of 41.8% was acquired at a concentration of 0.5%, which had the lowest zeta potential absolute value of 3.5 mV. It can be inferred that the increase in the zeta potential induced the growth of the energy barrier, which prevented particle agglomeration. The suspension with a lower zeta potential exhibited a better fine particle removal efficiency.

Results from Aerosol Measurement in Amine Plant Treating Gas Turbine and Residue Fluidized Catalytic Cracker Flue Gases at the CO2 Technology Centre Mongstad

This work discusses the relation between flue gas particle content, mainly related to sulfuric acid aerosols and dust, and corresponding MEA emissions. The work lays grounds for future necessary pre-treatment options for various flue gases with high aerosol content in order to operate post-combustion amine plants with minimum emissions.In 2015, the CO2 Technology Center Mongstad (TCM DA), operated a test campaign using aqueous monoethanolamine (MEA) solvent at 30 wt%. The main objective was to demonstrate and document the performance of the TCM DA Amine Plant located in Mongstad, Norway. Two weeks were dedicated to the aerosol measurement testing.

Physical and chemical characteristics of flue-gas particles in a large pulverized fuel-fired power plant boiler during co-combustion of coal and wood pellets

Fossil fuel combustion should be decreased in future years in order to lower the CO2 emissions of energy production. The reduction can be achieved by increasing the amount of CO2-neutral fuels in energy production. Here 6–13% of coal was substituted with industrial or roasted pellets in a pulverized fuel-fired power plant without making any changes to fuel grinding or low-NOx burners. The effect of pellet addition for the flue gas particles was studied with direct sampling from the boiler super heater area. Based on primary dilution ratio tests, transmission electron microscope images, and the natural electric charge of the particles, it was observed that particles in the flue gas are spherical and have been formed in the boiler at high temperatures. The pellet addition lowered the total particle number concentrations with all of the studied pellet–coal mixtures in comparison to the coal combustion. The 10.5% industrial pellet addition caused a second mode in the particle number size distribution. In addition, based on the chemical analysis of the collected size-fractioned particle samples, results indicated that the pellet addition did not increase the corrosion risk of the boiler. However, the changes in the particle number size distribution and total particle number concentration can affect the operation of electrostatic precipitators and flue gas cleaning.

배출가스 중 응축성미세먼지 특성 연구

배출가스 중 응축성미세먼지 특성 연구

Hollow fiber membrane separation process in the presence of gaseous and particle impurities for post-combustion CO2 capture

ABSTRACTThe membrane separation process for CO2 capture can be interfered by the gaseous components and the fine particles in flue gas, especially in desulfurized flue gas. In this work, the pint-sized Polyimide(PI) hollow fiber membrane contactors were self-packed to investigate the membrane CO2 separation from flue gas containing fine particles and gaseous contaminants (SO2,SO3,H2O). First, the effects of SO2, SO3, water vapor, and gypsum particles on the CO2 capture were studied independently and synergistically. The results showed that the effect of SO2 on the membrane separation properties is indistinctive; however, the membrane performance was damaged seriously with the addition of SO3. The high humidity promoted the CO2 separation initially before inhibiting the PI membrane performance. Moreover, the decrease of the CO2/N2 selectivity and the permeation rate were accelerated with the coexistence of SO2. The membrane performance showed an obvious deterioration in the presence of gypsum particles, with a 21% decrease in the CO2/N2 selectivity and 51% decrease in the permeation rate. Furthermore, the gypsum particles exerted dramatic damage. Under the WFGD conditions, the combined effects of SO2, water vapor, and the gypsum particles influenced the stability of the membrane significantly. This tendency is mainly attributed to the deposition of fine particles and aerosol on the membrane surface, which occupied the effective area and enhanced the mass transfer resistance. This study of impurities’ influence could play an important role in further industrial application of membrane CO2 capture.

Particle Agglomeration in Bipolar Barb Agglomerator Under AC Electric Field**supported by the Key Technology R&D Program of Hebei, China (No. 13211207D)

The development of an efficient technology for removing fine particles in flue gas is essential as the haze is becoming more and more serious. To improve agglomeration effectiveness of fine particles, a dual zone electric agglomeration device consisting of a charging chamber and an agglomeration chamber with bipolar barb electrodes was developed. The bipolar barb electric agglomerator with a polar distance of 200 mm demonstrates good agglomeration effectiveness for particles with a size less than 8.0 μm under applied AC electric field. An optimal condition for achieving better agglomeration effectiveness was found to be as follows: flue gas flow velocity of 3.00 m/s, particle concentration of 2.00 g/m3, output voltage of 35 kV and length of the barb of 16 mm. In addition, 4.0–6.0 μm particles have the best effectiveness with the variation of particle volume occupancy of −3.2.

Effects of coexistent gaseous components and fine particles in the flue gas on CO2 separation by flat-sheet polysulfone membranes

Nowadays, membrane separation technology has been one of the most effective technologies for CO2 capture. The coexistent components in the actual flue gas, such as water vapor, SO2, O2 and fine particles, may have a significant influence on the separation performance of polymeric membranes for CO2 capture. In order to comprehensively and systematically investigate the effects of these components, a series of lab-scale separation experiments for CO2 capture were conducted in the simulation test-bed with the commercially available flat-sheet polysulfone (PSF) membranes. At first, the operation conditions were optimized for CO2 separation by PSF membranes and the best operation conditions were 0.4MPa as the feed gas pressure, 400L/h as the residual gas flow rate and 50°C as the feed gas temperature. Then, the PSF membrane performances on CO2 separation in the presence of water vapor, SO2, O2 and fine particles in the actual flue gas were studied. It was found that water vapor promotes the CO2 separation performance of PSF membranes by a net increase of the CO2/N2 selectivity, CO2 permeability and CO2 enrichment efficiency. O2 slightly inhibits the CO2 separation performance, while the effect of SO2 is negligible. The gypsum fine particles significantly deteriorate CO2 separation performance of PSF membranes, which mainly results from the occupation of the effective membrane area, the increase of the mass transfer resistance and the partial adsorption of the gases by the gypsum fine particles deposited on the membranes.

Effects on a 50 MWth Circulating Fluidized-Bed Boiler Co-firing Animal Waste, Sludge, Residue Wood, Peat, and Forest Fuels

This work is a part of an effort to maximize the operational safety of a 50 MWth circulating fluidized-bed (CFB) boiler located in Perstorp, Sweden, co-firing animal waste, peat, waste wood, forest residues, and industrial sludge. An increase in the CFB boiler availability reduces the use of expensive fossil fuel (oil) in backup boilers during operational problems of the CFB boiler. The work includes a thorough mapping and analysis of the failure and preventive maintenance statistics, together with elemental analysis of boiler ash and deposits, flue gas, and fuel fractions. Correlations between boiler parameters and boiler availability are sought, and recommendations regarding boiler design and operation are made. An explicit description of the boiler is made to allow for the use of presented material as future reference material. It was observed that the failure frequency is especially high where (1) rapid chloride-rich windward deposit buildup is combined with (2) high construction material temperature and (3) windward soot blowing. In areas where one of these factors was absent, a more moderate material loss could be seen. The flue gas average elemental composition can be regarded as close to constant as it flows through the series of heat exchangers. Thus, the significant differences in deposit buildup of different flue gas cross-sections cannot be a result of changed average flue gas composition. The areas of the steam tubes suffering from rapid material loss are also exposed to high deposit rates. Downstream of a well-defined temperature threshold in the secondary superheater, neither material loss nor substantial deposit buildup could be seen. Tube deposits are dominated by Na, S, Ca, K, and P, but only Na, K, and S are enriched in the windward tube deposits relative to the fly ash bulk composition. The temperature of the flue gas is the major parameter governing the rate of deposit buildup in the boiler heat exchangers. Of the fuel nitrogen, 95 wt % leaves the process as N2(g). Fuel mix ash content analysis via a separate ashing of different fuel fractions by heating to 550°C does not reflect the ash content of the fuel mix correctly. The soot blowing angle of attack on the deposits should be regarded in areas with rapid deposit growth when boilers and soot blowers are designed to allow for efficient tube cleaning. The use of heterogeneous fuel in the boiler creates strong variations in fuel, flue gas, and particle composition and makes it increasingly important to have online measurements to be able to understand and control the furnace chemistry. The filter ash in the flue gas baghouse filter effectively sorbs HCl(g) and NH3(g) from the flue gas already without the addition of sorbents. Online flue gas measurement to control the furnace chemistry must therefore be installed upstream of the filter to enable accurate control. Also, a significantly larger filtration area can be installed in the baghouse filters with a slight increase in cost, to allow for efficient use of the ash as free of cost sorbent and lowered emission levels. Scanning electron microscopy analysis of the flue gas deposits shows that no pieces of ground bone, sand particles, or other relatively large flue gas particles contribute directly to the deposit buildup. White crystals rich in N and Cl, most likely ammonium chloride, precipitate downstream of the flue gas filter. The precipitation interferes with the dust emission measurement and forces a reduced usage of waste-derived fuels because of the exceedance of environmental limits. More expensive forest fuels are used to replace waste-derived fuels, resulting in a higher fuel cost.

Numerical analysis of the flue gas-coal particles mixture flow in burner's distribution channels with regulation shutters at the TPP Nikola Tesla - A1 utility boiler

Pulverized coal particles concentration distribution across the burner's distribution channels, especially where plasma torches are installed, is one of the key issues for efficient implementation of plasma system for liquid fuel free combustion support at the pulverized coal fired boilers. The possibility of pulverized coal particles concentration increase at the lower burner channels of TPP Nikola Tesla - A1 boiler using regulation shutters is analyzed experimentally and numerically. Subject of present work is two-phase flue gas-particles mixture flow in burner's distribution channels with regulation shutters installed at the TPP Nikola Tesla - A1 boiler. Aim of this work is to optimize position of implemented system of shutters to achieve desired concentration and velocity distribution in channels with plasma torches, using numerical modelling. Experimental investigation was performed for the verification of proposed mathematical model for the prediction of the analyzed two-phase flow. Based on verified model, numerical parametric analysis was done. Obtained results of gas phase velocity field, coal particles concentration field, velocity and concentration profiles clearly show the dependence between shutters position and the coal particles mass flow rate and concentration distribution at the outlet cross-section of the burner's distribution channels. According to the numerical optimization results suitable modification of the shutter system is proposed.

Effect of turbulent–laminar flow transition on degradation of de-NO x catalyst

In this study, the effect of the flow behavior on degradation of a de-NO x catalyst is experimentally and numerically investigated. The results show that the degradation of the de-NO x catalyst is remarkably affected by the inner flow behavior, namely turbulent–laminar flow transition. The degradation of the catalyst is enhanced in the upstream region near the inlet, since injected turbulent flow facilitates particles in flue gas to adhere the catalyst surface. In the downstream region, on the other hand, the degradation of the catalyst is gentle. This is due to the fact that the inner flow varies from turbulent to laminar flow toward downstream, which prevents particle from adhesion to the surface.

New High Voltage Pulse Generators

The use of High Voltage Pulses has found applications in biotechnology, medicine, industrial applications, and food processing and preservation. Biotechnology application includes electro-chemotherapy, gene transfer, electroinsertion of proteins into cell plasma membrane, electrofusion of cells, transdermal drug delivery, water treatment and food. Industrial applications of High Voltage Pulses include the filtering of flue gas particles using electrostatic precipitators, treatment of metal and polymer materials by plasma immersion ion implantation, exciter lasers fabrication, flash radiography or ionization, polarization source in accelerators, insulation testing and so on. Efficiency of all these applications strongly depends on parameters of electric pulses, which are delivered to the treated object using specially developed electrodes and electronic devices. In this paper, the design and structure of high-voltage pulse generator will be described. We have presented most commonly used techniques of signal generation based on various methods such as: Marx cells and spark gaps, MOSFET series and parallel, IGBT, nonlinear capacitor, static induction thyristor, and modular high voltage. Methods of high voltage pulse generators based on various shape of pulse are also presented. Keywords: Marx generator, MOSFET, IGBT, nonlinear capacitor, pulse shaping network, thyristor

Fate of Cu, Cr, and As During Combustion of Impregnated Wood with and without Peat Additive

The E.U. Directive on incineration of waste regulates the harmful emissions of particles and twelve toxic elements, including copper, chromium, and arsenic. More information is critically needed on the speciation and behavior of these trace elements during combustion, including the effects of different process variables, as well as of different fuels and fuel mixtures. Using a 15 kW pellets-fueled grate burner, experiments were performed to determine the fate of copper, chromium, and arsenic during combustion of chromate copper arsenate (CCA) preservative wood. The effects of co-combustion of CCA-wood with peat were also studied since peat fuels previously have proved to generally reduce ash related problems. The fate and speciation of copper, chromium, and arsenic were determined from analysis of the flue gas particles and the bottom ash using SEM-EDS, XRD, XPS, and ICP-AES. In addition, chemical equilibrium model calculations were performed to interpret the experimental findings. The results revealed that about 5% copper, 15% chromium, and 60% arsenic were volatilized during combustion of pure CCA-wood, which is lower than predicted volatilization from the individual arsenic, chromium, and copper oxides. This is explained by the formation of more stable refractory complex oxide phases for which the stability trends and patterns are presented. When co-combusted with peat, an additional stabilization of these phases was obtained and thus a small but noteworthy decrease in volatilization of all three elements was observed. The major identified phases for all fuels were CuCrO2(s), (Fe, Mg, Cu)(Cr, Fe, Al)04(s), Cr2O3(s), and Ca3(AsO4)2(s). Arsenic was also identified in the fine particles as KH2AsO4(s) and As2O3(s). A strong indication of hexavalent chromium in the form of K2CrO4 or as a solid solution between K3Na(CrO4)2 and K3Na(SO4)2 was found in the fine particles. Good qualitative agreement was observed between experimental data and chemical equilibrium model calculations.

脱硝触媒内の流れ挙動が劣化に及ぼす影響

The effect of flow behavior on degradation of de-NOx catalyst is experimentally and numerically investigated. The de-NOx rate for used catalysts is evaluated using laboratory-scale test apparatus. and the flow behavior in a honeycomb rectangular tube of the catalyst is studied by direct numerical simulations (DNS). The results show that the degradation of the catalyst is enhanced in the upstream region near the inlet. This is due to that the injected flow is a turbulent flow, which facilitates particles in flue gas to attach the catalyst wall, and the flow becomes laminar downstream in the catalyst.

Characteristics of slag, fly ash and deposited particles during melting of dewatered sewage sludge in a pilot plant

This study examines slag, fly ash, and deposited particles during melting of dewatered sewage sludge in a pilot plant. In addition, the chemical composition of particles in flue gas was simulated using a thermodynamics program, namely FACTSage 5.2. The results showed that the main components of slag were Al, Fe, Ca, P and Si; the minor components were Na, K, Mg, Cu, and Zn. The main chemical compound of slag was Ca 4(Mg,Fe) 5(PO 4) 6. For fly ash particles, heavy metals with the highest concentrations were in the order of Zn and As, Pb, Cu, and Cd, respectively. For non-heavy metals, Al, Fe and P were also found in significant amounts. The majority of deposited particles were composed of elements of Zn, P, S, Na, Fe, Al, Si, and Ca and such chemical compounds as Zn 3(PO 4) 2, AlPO 4, FePO 4 and Fe(OH) 3 while the minority consisted of elements of As, Cu, and Pb. Moreover, the compositions of deposited particles in each chamber differed due to different flue gas temperatures inside. In the secondary chamber at 760 °C, the amounts of Fe and Al were higher than Zn, whereas, in the other chambers (600–400 °C), the amount of Zn was higher. In other words, at the lower temperature the deposition of Zn was higher than the deposition of Fe and Al. In the water cooling section, volatile elements (i.e. Zn, As, Cu, Pb) were found in the highest concentrations due to a big difference in temperature between the wall surface and flue gas. From the simulation results, most of the elements in the gas phase were found to be chloride compounds, whereas those in the solid phase were in the form of oxide, sulfate, and phosphate compounds.