Optimisation of one stage electrostatic precipitator for welding fume filtration

AbstractIn addition to huge installations of electrostatic precipitators (ESP), as those employed for dust filtration in blast furnaces and cement factories, there are also small devices as the ones used for fume filtration in welding shops. The aim of this paper is to optimize the geometric characteristics and the electric operating conditions of a “one-stage” precipitator intended for the filtration of welding fumes. The experimental bench is composed of 2 units, each consisting in an horizontal wire (tungsten, diameter 0.1 mm), energized from a high-voltage supply (+15 kV, 5 mA), and equally distant from two vertical plate electrodes (aluminium, length 200 mm × variable width) connected to the ground. Two “one-factor-at-a-time” experiments paved the way for a composite experimental design that enabled the optimization of ESP geometry, i.e. the inter-electrode interval and width of the collecting electrodes

Sustainable process for the production of methanol from CO2 and H2 using Cu/ZnO-based multicomponent catalyst

AbstractWe have performed R&D project on methanol synthesis from CO2 and hydrogen in order to contribute to CO2 mitigation. High-performance Cu/ZnO based multicomponent catalysts were developed. The roles of metal oxides contained in Cu/ZnO-based catalysts were classified into two categories: (1) Al2O3 or ZrO2 improves the dispersion of copper particles in the catalyst; (2) Ga2O3 or Cr2O3 increases the activity per unit copper surface area of the catalyst. The long-term stability of Cu/ZnO-based catalysts during methanol synthesis from CO2 and hydrogen was improved by adding a small amount of silica to the catalysts. Silica added to the catalysts suppressed the crystallization of ZnO contained in the catalysts. The catalysts were found to be highly active and extremely stable in methanol synthesis from CO2 and hydrogen. In the next step, a bench plant with a capacity of 50 kg day−1 of CH3OH, which was equipped with facilities for recycling unreacted gases and gaseous products, was successfully operated. The purity of crude methanol produced was 99.9 wt%, whereas the purity of crude methanol produced from syngas in a present-day commercial plant was reported as 99.6 wt%

Modeling of a two stages electrostatic air precipitation process using response surface modeling

Any industrial process needs to work with the optimal operating conditions and thus the evaluation of their robustness is a critical issue. A modeling of a laboratoryscale wire-to-plane two stages electrostatic precipitator for guiding the identification of the set point, is presented this in paper. The procedure consists of formulating recommendations regarding the choice of optimal values for electrostatic precipitation. A twostages laboratory precipitator was used to carry out the experiments, with samples of wood particles of average granulometric size 10 μm. The parameters considered in the present study are the negative applied high voltage of the ionization stage, the positive voltage of the collection stage and the air speed. First, three “one-factor-at-a-time” experiments were performed followed by a factorial composite design experiments, based on a two-step strategy: 1) identify the domain of variation of the variables; 2) set point identification and optimization of the process

Modeling of A Two Stages Electrostatic Air Precipitation Process using Response Surface Modeling

Any industrial process needs to work with the optimal operating conditions and thus the evaluation of their robustness is a critical issue. A modeling of a laboratoryscale wire-to-plane two stages electrostatic precipitator for guiding the identification of the set point, is presented this in paper. The procedure consists of formulating recommendations regarding the choice of optimal values for electrostatic precipitation. A twostages laboratory precipitator was used to carry out the experiments, with samples of wood particles of average granulometric size 10 μm. The parameters considered in the present study are the negative applied high voltage of the ionization stage, the positive voltage of the collection stage and the air speed. First, three “one-factor-at-a-time” experiments were performed followed by a factorial composite design experiments, based on a two-step strategy: 1) identify the domain of variation of the variables; 2) set point identification and optimization of the process

Measurement of total electric charge of submicrometer particles using a DBD charger coupled with a capacitive sensor

International audienceThe objective of this experimental research work is to evaluate the efficiency of a capacitive system for particles charge measurement. The obtained results are used to assess the performance of an aerosol DBD charger based on the particle losses. The charge measurement system consists of a sensitive electrometer that determines the total charge of the particles flowing through a capacitive sensor, and a DBD charger that is used to charge particles at elevated levels. The results are compared to that obtained using an Electrical Low Pressure Impactor (ELPI+). Experimental results show similar behavior of both detection instruments employed in this study. In particular, equivalent trend, order of magnitude and polarity of total charge are obtained for different status of the DBD charger (different frequency, voltage and geometry)

Modelling the Dynamic Interaction Power System Lamp - Application to High Pressure Mercury Gas Discharge Lamps

The aim of this paper is to study the dynamic behaviour of a plant constituted by an electrical power system and a gas discharge lamp, this latter, increasingly used in street lighting, remains a nonlinear load element. Various approaches are used to represent it, one is the approximation of the discharge represented by a hot "channel", which verifies the assumption of local thermodynamic equilibrium [LTE] or the polynomial form of the conductance variation. A calculation procedure, based on "channel" approximation of the high pressure mercury (HPM) gas-discharge lamp, is developed to determine the physical and electric magnitudes, which characterize the dynamic behavior of the couple "lamp-electrical power system". The evolution of the lamp properties when principal parameters of the discharge (pressure of mercury, voltage supply, frequency) are varying were studied and analyzed. We show the concordance between simulation, calculations and measurements for electric, energetic or irradiative characteristics. The model reproduces well the evolution of properties of the supply when principal parameters of the discharge vary

Effect of SnS addition on the morphological and optical properties of (SnS)m (Sb 2 S 3 )n nano-rods elaborated by glancing angle deposition

International audience(SnS)m(Sb2S3)n thin films were prepared by thermal evaporation using the glancing angle deposition technique (GLAD). The incident angle between the particle flux and the normal to the substrate was fixed at 80°. The Raman and XRD characterization revealed the amorphous character of the films due to the columnar structure as shown by the SEM characterization and AFM analysis. A strong change of the surface morphology of the films was observed and it depends on the composition. Optical properties were extracted from transmittance T and reflectance R spectra. (SnS)m(Sb2S3)n thin films exhibit high absorption coefficients (104–2 × 105 cm−1) in the visible range and the higher values were obtained for Sn3Sb2S6 and it has the highest photocurrent values. The direct band gap (Eg dir) was in the range 2.11–1.67 eV. The refractive indices are calculated from optical transmittance spectra of the films. The Sn3Sb2S6 sample exhibits a lower refractive index. All the dispersion curves of refractive index match well with the Cauchy dispersion formula and they were analyzed using Wemple-DiDomenico model. The Bruggeman effective medium approximation EMA was used to calculate the packing density of different compositions, and SnSb4S7 sample has the highest value. The so-called Verdet coefficient was evaluated from refractive index dispersion, and it was enhanced near the band gap