Evaluation Of The Emission Impact And The Effect Of Exhaust Gas Reform For Heavy Duty Diesel Truck In A Typical Area

In recent years,with the development of urban economy,the number of motor vehicles is increasing rapidly in Shunde District.Among them,Heavy-duty diesel vehicles are accelerating the formation of atmospheric composite pollution in the region.Therefore,it will be an important prerequisite for the development of tail gas treatment to master the pollution emission characteristics of heavy-duty diesel trucks and evaluate the effectiveness of the pilot project for tail gas reform.This study compiled the 2016 pollution emission inventory of heavy-duty diesel trucks in Shunde District and analyzed the spatial distribution characteristics of major pollutant emissions based on the field research data;Simulated the air quality of Shunde District in 2016 through the WRF-CMAQ air quality model system and subsequently verified the reliability of the air quality model system using actual observed data;The study further assessed the contributions of local anthropogenic emissions and local heavy-duty diesel trucks emissions to the concentrations of NO2,PM10 and PM2.5 in Shunde District under two control scenarios;Finally,the study analyzed the results of tracking test,bench emission test and vehicle emission test of A,B,C,D four DOC+CDPF post-processing devices,and comprehensively evaluated the actual emission reduction effects of various post-processing devices on the emission factors of smoke value,CO,Total hydrocarbon(THC),particulate matter(PM)and other gaseous pollutant and the impact on operating conditions of heavy-duty diesel trucks,identified the products with superior overall performance of DOC+CDPF.The research results showed that there were 14,701 tons of NOx,550 tons of PM10 and 505 tons of PM2.5 from the heavy-duty diesel trucks of Shunde District in 2016,accounting for 86.72%,89.72% and 89.38% of the total amount of the road movement sources respectively,which were main road movement sources of the contribution for NOx and PM in Shunde District.The high-emission areas are mainly along the main traffic trunk line of Shunde District.The model simulation results showed that the contribution of PM pollution to Shunde District was mainly from regional transmission in 2016.Local anthropogenic emissions only contributed 18.8% and 15.7% to the concentrations of PM10 and PM2.5,respectively.Among them,the emissions of local heavy-duty diesel trucks contributed 1.3% and 1.7% to the concentrations of PM10 and PM2.5 in Shunde District.And the local contributions for PM in(Dec-Feb)were less than Jun and Jul.In addition,the concentration of NO2 was mainly contributed by local anthropogenic emissions(60%)from Shunde District in 2016.Among them,the contribution rate of heavy-duty diesel trucks for NO2 was 19.5%,it was one of the main sources for NO2 pollution,and the contribution rate of both emission sources to NO2 concentration in the higher temperature month of(Jul-Sep)were greater than that of(Nov-Jan).At last,the results of tracking test showed that the proportion of heavy-duty diesel trucks whose smoke values reached the local standard limit of Guangdong Province was 94.7%,93.8%,100.0% and 100.0% respectively,after installing A,B,C,D four DOC+CDPF post-processing devices.The catalytic regeneration efficiency of the A post-processing device is optimal.The results of bench emission test and vehicle emission test showed that various post-processing devices could effectively reduce the emissions of CO,THC and PM in the exhaust from the heavy duty diesel trucks,and the reduced rates for the emission factors of PM is the best,the range were in 86%~95%,However,the four post-processing devices have problems in increasing the ratio of NO2/NOx,the emission factor of CO2 and fuel consumption.Overall,A post-processing device had better overall performance.