The Impact Of The Emissions Of Air Pollutants From A Typical Petrochemical Company On Air Quality By Modeling Approach

As the implementation of the"12th Five-Year Plan for Energy Development",China has implemented the development strategy of large-scale and intensive construction of petroleum refining bases in order to strengthen the oil and gas energy supply capacity and reduce its external dependence.With the continuous improvement of petroleum refining capacity,structural pollution mainly caused by petrochemical companies has become increasingly prominent.Accurately assessing the impact of petrochemical company emissions on surrounding air quality and scientifically strengthening control measures is becoming an important management demand for local governments gradually.In view of this,based on the2017 air pollutant emission inventory of Dayawan,a district of Huizhou city,we accounted the air pollutant emissions from a typical petrochemical company located in Dayawan using the calculation methods of the"working guide for petrochemical company emissions".Furthermore,the shutdown and production increase impacts of the petrochemical company on the surrounding air quality were quantified using the WRF-CMAQ modeling system.Emission inventory results indicated that the emissions of SO₂,NO_x,PM₁₀,PM_2.5,CO and VOCs from the selected petrochemical company were 212,1744,455,359,1458 and6446 t respectively in 2017,which accounted for 6.74%,5.21%,5.31%,8.72%,3.42%and11.62%of the total emissions from Dayawan.It showed that VOCs is the mainly air pollutant of the petrochemical company,of which disorganized emissions accounted for about 90%,and the main emission links are waste water collection and treatment fugitive,organic liquid storage and blending volatilization and cooling system emissions.After the implementation of emission alternatives and strict reduction measures,the selected petrochemical company achieved a doubled production,but the VOCs emissions were significantly decreased by 30%,while the emissions of other pollutants increased by 6%to 19%compared to that in 2017.Simulation results showed that the emission contribution of the selected petrochemical company to the concentrations of NO₂,PM₁₀,PM_2.5and O₃in Dayawan was 0.91,0.64,0.54and-0.08μg·m^-3respectively in 2017.The shutdown of the selected company contributed the most to NO₂declines in the surrounding national-controlled air-monitoring stations,such as the Guanweihui station in which the NO₂can be reduced by 1.24μg·m^-3（with a decline rate of 5.10%）;however,due to the effect of NO titration,the NO_xemission reduction of the selected company exerted slight negative contribution to O₃in the Guanweihui and Xiachong stations.The production increase and technology transformation of the selected company exhibited a significant impact on O₃decreases in the surrounding stations,in which the O₃concentrations can be decreased by up to 2.45μg·m^-3（with a decline rate of 1.72%）,and the overall O₃concentrations in Dayawan can be also decreased by 0.82μg·m^-3.In addition,affected by the poor air diffusion condition and the transported pollutants from upwind areas in autumn and winter,the emissions of the selected company made significant positive contributions to the concentrations of NO₂,PM₁₀and PM_2.5in the Guanweihui station in January and October,while an obvious negative contribution to O₃in January due to the low temperature and decreased radical activity in winter.