Composite oxide purification of diesel exhaust pollutants

Title: Composite oxide purification of diesel exhaust pollutantsAuthor: Tao Wang QunDegree awarded: Wuhan University of TechnologyKeywords: diesel engine;; emissions;; perovskite;; oxidation catalytic converter;; electric heatingSummary:Diesel exhaust is the main pollutants PM and NOx, up to 50 times as much gasoline, so the control of diesel exhaust pollutants mainly in the PM and NOx control. Appropriate control methods into machine control and machine control technology outside the home and abroad for PM control is mainly used by optimizing combustion and particulate trap (DPF) for Neodymium magnets trapping methods, mainly for the use of NOx control options of catalytic reduction (SCR) and exhaust gas recirculation technology (EGR) control.As the diesel engine combustion is oxygen-rich combustion, oxidation catalytic converter can be used (OCC) for processing, consumption of particulate soluble organic components in the SOF to reduce particulate emissions, but also reduce HC and CO emissions.Although the oxidation catalytic converter for purifying effect of particles is far less particulate trap, but hydrocarbons of low ignition temperature (170 ℃ in the following renewable), so the oxidation catalytic converter does not require costly regeneration system investment costs are lower. The oxidation catalysts used in the precious metal catalyst and the catalyst are of concern in recent years, rare earth catalyst, the catalyst resistance to sulfur poisoning ability of noble metal than earth, experiments show that the perovskite-type oxide catalyst is better, but China's rare earth resources, and therefore This selection of a perovskite-type oxides La0.9K0.1Co03 as a catalyst.But whether it is rare precious metal catalyst or catalyst, the catalytic effects are largely dependent on diesel engines with low exhaust temperature, while the diesel engine exhaust gas temperature is relatively low, especially in the light-duty diesel engines, usually in the low speed and load operating conditions, exhaust gas temperature is difficult to achieve good catalyst operating temperature, so this paper presents electric heating catalyst solution, that is low in the case of diesel exhaust temperature electric heating under way to improve the temperature of the catalyst to improve the catalytic effect, using the electric heating device for the stainless steel heating tube, and the engine test bench to do a comparison, not in the same conditions compared to their heating and after heating the catalyst diesel emissions changes, verify a viable electric heating solutions and experimental results show that http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php when the heating temperature rises to above 400 ℃, the catalytic effect is significantly improved, in particular, but also a reminder of the NOx conversion efficiency has improved significantly.Finally, the paper controls for electric heating temperature to do the analysis, put forward a simple and reliable method of control and relay high-precision PID closed loop control method, by comparing the two control methods and the characteristics of this electric heating systems and requirements analysis , to take relays that control electric heating method of temperature control is more appropriate.Degree Year: 2010