Research And Development Of Ozone Generator For Pulping

Ozone is the strongest oxidant available in the industry and has a good degradation effect on lignin.It is a good gaseous bleaching agent and can be used for pretreatment of raw materials.Ozone is clean and environmentally friendly and does not produce any pollutants.Ozone is used in pulping will be a trend in the future.However,due to the limitation of the ozone generating device,the pressure of generating ozone is less than 0.1 MPa,which limits the industrialization of ozone.If a high-pressure(0.4 MPa~0.6 MPa)type ozone generator can be developed,ozone will be more widely used in pulping.Based on the theory of ozone generated by discharge method,a high-pressure ozone generator suitable for pulping(pressure 0.4 MPa~0.6 MPa,ozone concentration greater than 70 g/m3)was designed,and the performance and structure were explored.In this paper,the theory of ozone generation by discharge method under high pressure condition was analyzed.It was determined that the main reason for the influence of air pressure on ozone generation was reducing the equivalent field strength(E/N)in the discharge space.By comparing the concentration,it was found that the performance of creeping discharge at high pressure was better than that of silent discharge.The discharge form of high-pressure ozone generating device initially was determined to the surface discharge form.By investigating the working mechanism of creeping discharge,it is found that the voltage,frequency,gas pressure,the properties of the dielectric layer and the structural form of the high voltage electrode all have an important influence on the strength of the creeping discharge.An ozone generating tube with a tubular single space double grounding pole based on the surface discharge was designed.The main structure of the ozone generating tube were mainly studied and designed.We mainly discussed the influence of the pressure,the voltage,high-voltage electrode materials,wire diameter,the thickness of the dielectric layer and the inlet flow rate on the ozone generated by the discharge when the pressure was 0.4 MPa,0.5 MPa and 0.6 MPa.The conclusion is as follows:(1)The ozone concentration,production and the yield decreased with the increase of the gas pressure.The influence of the gas pressure on the discharge power was small.(2)Ozone concentration,production,yield and discharge power increased with increasing voltage.In addition,the higher the gas pressure,the greater the initial voltage of ozone.(3)The metal material with less work function was more favorable for the generation of ozone.(4)Ozone concentration,production and yield decreased with the increase of the wire diameter of the high voltage electrode,but the wire diameter has little effect on the discharge power.(5)When the thickness of the dielectric layer increased,the ozone concentration,production and yield showed a trend of increasing first and then decreasing.The discharge power decreased with the thickness of the dielectric layer increases.(6)As the intake flow increased,the ozone concentration,production and yield gradually increased,but the increasing trend became slower and slower.Based on the previous experiments,the feasibility of industrial application was initially explored.The self-made high pressure ozone generating tubes compared with the ozone compression system actually operated by a factory,the overall performance was better than the latter.