Study On The Dispersion Law Of Volatile Organic Compounds In Oil Field And Photocatalytic Treatment

With the increasing emphasis on environmental protection by the state and people,research on volatile organic compounds（VOCs）is increasing.At present,there are many researches on VOCs in coastal cities and other industries in China,but less on oilfield enterprises in Northwest China.Therefore,it is very necessary and urgent to carry out the research and management of the current situation of VOCs in the oilfield operation site.This paper studies the VOCs dissipation of an oilfield enterprise in the Ordos Basin,and the research results as follows.（1）The VOCs emission sources of oilfield stations can be divided into 8 categories,namely,crude oil storage tank vent,loading and unloading port of the oil unloading station,heating furnace flue gas discharge port,measuring oil port of produced water storage tank,mud treatment area at mud treatment station,sealing point of the external pump,maintenance department,sampling port for sample collection;and a total of 60 VOCs were detected;eight types of VOCs,45 species,36 species,45 species,42 species,45 species,32 species,and 45species were detected in sequence.VOCs emission concentration is between 11⁷7406mg/m³,and High concentration of VOCs in crude oil storage tanks and unloading stations.The number of VOCs in the 8 types of sources and the total concentration of each species are alkane>aromatics>olefins,and the main components are C₂^C₆ alkanes.（2）There are 60 kinds of VOCs with a detection rate of over 80%in the environmental atmosphere of the oilfield boundary.The number and concentration of alkanes are the highest,and the main components are C₂^C₆ alkanes,isoprene,cis-2-butene and benzene series.The peak value of daily variation of VOCs in the environmental atmosphere of the oilfield boundary appears at 5:00,and the lowest value appears at 15:00.The peak value of monthly variation of VOCs appeared in January,and the lowest value appeared in July.Seasonal variation of VOCs concentration is winter>autumn>spring>summer.VOCs concentration decreased significantly after rainfall.VOCs concentration decreases with increasing temperature.（3）The ozone formation potential of VOCs in the environmental atmosphere of the oilfield boundary is 4527.95×10^-9,and the contribution rate is followed by aromatic hydrocarbons>olefins>alkanes.Its key active species are aromatic hydrocarbons,and the key active components are trimethylbenzene,xylene,toluene,C₂～C₅ olefins and C₃～C₅ alkanes.The secondary organic aerosols formation potential is 94.45μg/m³,and the largest contribution is aromatic hydrocarbons.（4）TiO₂/ACF composite photocatalysts with TiO₂ loadings of 1%to 5%were synthesized by immersion pulling method and evaluated by toluene removal test,and the results show that the overall effect of TiO₂/ACF composite photocatalyst with TiO₂ loading of 3%is better.The photocatalytic process for the removal of toluene by TiO₂/ACF composite photocatalyst is consistent with the Langmuir-Hinshelwood kinetic model,and it is quasi-first order reaction.On-site photocatalytic test in the field station using self-made TiO₂/ACF composite photocatalyst,and the test results show that it has a good removal effect on VOCs of oilfield.