Preparation And Properties Of Environmental-friendly Carboxymethyl Cellulose-based Demetallization Agents For Crude Oil

In recent years,the proportion of the unconventional crude oil in the petrochemical industry has greatly increased with the increasing of global oil demand and the depletion of the conventional crude oil.The unconventional crude oil has relatively high content of heavy metals in complex forms,such as nickel and vanadium,which could do considerable harm to the petroleum processing,and they are very difficult to remove from crude oil.Currently the industrial process of removing nickel and vanadium is complicated and costly.Besides,most of the demetallization agents which contain element phosphorus can cause environmental pollution.Thus,the study on developing a new economic and environmentally-friendly chelating demetallization agent has become a popular and difficult point in the field of petroleum.The main research contents are exhibited as follows:Sodium carboxymethyl cellulose?CMC?,carbon disulfide?CS2?,hydroxypropyl acrylate?HPA?and acrylamide?AM?were used to synthesis environmentally friendly demetallization agents:DTC-CMC and CMC-HPA-AM,and they were characterized and analyzed by some professional equipment and methods such as Infrared?IR?,Scanning Electron Microscopy?SEM?.Besides,the-effects of synthesis conditions and electric desalination processes on the removal efficiencies of nickel and vanadium from Oman-Basra crude oil were studied in details.?1?For DTC-CMC,it is found that the best synthesis condition of DTC-CMC is as followings:alkalized and esterification time is each of 90min and molar ratio between CMC and CS2 is 1:2.5;the best demetallization condition is as followings:removal temperature is 130?,the amount of demetallization agent is 400ppm and stand reaction time is 40min.In these conditions,the removal efficiencies of nickel and vanadium from crude oil can reach 28.9%and 34.9%,respectively.?2?For CMC-HPA-AM,it is found that the best synthesis condition of DTC-CMC is as followings:reaction temperature is 85 ?,reaction time is 3h,n?CMC?:n?HPA?:n?AM?is 1:1:3,initiator amount is 8%,chain transfer agent amount is 5%;the best demetallization condition is as followings:removal temperature is 130?,the amount of demetallization agent is 500ppm and mixing intensity is 200 times.In these conditions,the removal efficiencies of nickel and vanadium from crude oil can reach 32.4%and 38.1%,respectively.Besides,in order to enhance the demetallization performance and lower the cost,several complex monomer including C6H8O7,?NH4?2C₂O₄,CH4O3S and C3H4O3 were introduced to form a series of complex demetallization agents with CMC-HPA-AM.The result shows that the complex demetallization agent?CMC-HPA-AM?40%?,C6H8O7?15%?,?NH4?2C₂O₄?15%?,CH4O3S?30%??exhibit best nickel and vanadium performance:35.3%and 41.5%,respectively.