Study On Electrostatic Precipitation Enhancement Of Particles By Regulation Of Temperature And Particle Properties

China was the largest consumer of energy in the world and the energy structure was still dominated by coal in a short period of time.The coal-fired power generation was the most important way of energy consumption in the downstream of coal industry.Electrostatic precipitators?ESPs?are widely used in collecting fly ash samples because of their low cost and technical advantages,such as low-pressure drop,stability,and adaptability features.It was the preferred method for particle removal in flue gas.There were many coal producing areas,the coal quality was complex and variable,and the relative reserves of sulfur-containing coal were high in China.The combustion of sulfur-containing coal causes more SO₃ in the flue gas,and the concentration of SO₃ in the flue gas of industrial boilers,steel,non-ferrous metal smelting and other industries was also quite high.In the low low temperature range,SO₃ will condense on the surface of the particles,changing the dielectric constant and resistivity of the particles,etc.,so that the charge and removal efficiency of the particles change.At the same time,the dust accumulation on the collection plate will adversely affect the stable corona discharge of the electrostatic precipitator,which will greatly reduce the removal efficiency of the particles,which was a major challenge for the electrostatic precipitator.Therefore,the effects of SO₃ atmosphere on corona discharge and particle resistivity,charge and dust collection in dust collector,and the influence of electrode dust accumulation on corona discharge were studied in depth,and the removal efficiency of particulate matter in coal-fired flue gas was improved.To achieve deep purification of particulate matter in coal-fired flue gas,providing technical support for the promotion of ultra-low emissions was of great significance for improving the status of air pollution in China.This paper focuses on the electrostatic precipitator technology,mainly studies the particle charging characteristics under the influence of SO3.By adjusting the flue gas parameters and the polar matching form,the method of strengthening the particle charging was obtained.The temperature was studied for the dust deposited on the collection plate of the electrostatic precipitator.The effects of dust resistivity,dust thickness and discharge spacing on discharge characteristics and spatial field strength,systematically study the influence of flue gas parameters and dust layer accumulation on electrostatic removal;finally,study the separation of particles under different temperature,humidity and SO₃ concentration.In addition to the characteristics,a method of enhancing particle removal was proposed to achieve the purpose of efficient electrostatic removal of particles.First,the particle charging characteristics were studied.The charging characteristics of fly ash particles were studied under different flue gas conditions such as temperature,CO₂,SO₂ and SO₃.The effect of SO₃ on the particle dielectric constant and spatial ion concentration was studied,which affected the charge of the particles.SO₃ had both inhibitory and promoting effects on particle charging.At low concentration,it will increase the charge of the particles.At high concentration,it will inhibit the charge of the particles,and theoretically analyze it.At the same time,the charge law of SO₃ aerosol was also studied.The effect of different electrode forms on the charge of fly ash particles,as the acupuncture angle decreases,the particle charge increases continuously.The particle charge of particle size 0.128?m and 1.22?m increases by 2.52 and 1.16 times respectively..A method for enhancing the charge of particles in an electrostatic precipitator by optimizing the shape of the discharge electrode and regulating different flue gas parameters,increasing the ion concentration in the space and the dielectric constant of the particle was obtained.Secondly,when the dust was accumulated on the collection plate,the discharge characteristics of the electrostatic precipitator and the change of the spatial field strength were studied.The effects of temperature,accumulated dust thickness,discharge spacing,dust resistivity and other key parameters on the discharge characteristics were analyzed,and the corresponding relationship with the threshold voltage of anti-corona occurred.The spatial field strength at the occurrence of back corona was also analyzed.The impact of the above factors on the spatial strength of the space within the precipitator.When the voltage between the plates was 22 kV,the effective space field strength increases from 2.76 kV/cm to 4.15 kV/cm as the resistivity decreases from 8.45×10¹⁰?·cm to 6.27×10⁹?·cm,an increase of 50.6.%.A method of reducing the resistivity of the particles to 10¹⁰?·cm or less by temperature,humidity,and SO₃ control to ensure stable corona discharge of the dust collector and improving the spatial field strength was obtained.Finally,the research on the electrostatic trapping of particles in sulfur-containing flue gas by temperature and humidity was carried out.The effects of temperature parameters such as temperature,humidity and SO₃ concentration on particle removal efficiency and particle driving speed were studied.When the specific dust collection area was 41 m²/?m³/s?,when the temperature was lowered from 150°C to 80°C,the particle removal efficiency increases from 76.63%to 87.77%,an increase of 14.55%,and the driving speed was from 3.40 cm/s increased to 4.92 cm/s,which increased by nearly 44.58%;the relative humidity increased from 8.7%to 14.7%,and the particle removal efficiency increased from 93.99%to 95.05%,an increase of 1.13%,and the particle driving speed Increased from 6.92 cm/s to 7.40 cm/s,respectively,an increase of 6.93%.