高吸附容量吡啶基聚合物刷脱除原油中金属的机理研究

通过硅烷偶联和自由基聚合反应，合成了以SiO₂为核、聚4-乙烯基吡啶(P4VP)为壳的聚合物刷(P4VP@SiO₂)。采用红外光谱(FT-IR)、热重分析(TGA)、透射电镜(TEM)和扫描电镜(SEM)等手段对P4VP@SiO₂的结构进行了表征。将P4VP@SiO₂用于脱除原油中的镍和钙，分析了电脱盐工艺条件对其原油脱镍率和脱钙率的影响，并考察了P4VP@SiO₂的再生性能，提出了聚合物刷的脱金属机理。结果表明：随着P4VP@SiO₂加入量和沉降时间的增加，P4VP@SiO₂对原油的脱镍率和脱钙率先升高后趋于稳定；随着水/油质量比、乳化剪切强度、电脱盐温度和电场强度的增加，P4VP@SiO₂对原油的脱镍率和脱钙率先升高后降低。当P4VP@SiO₂用量为6000 μg/g、水/油质量比为0.15、电脱盐温度为120 ℃、乳化剪切强度为8 kr/min、电脱盐低压电场强度为500 V/cm、高压电场强度为1000 V/cm、沉降时间为60 min时，P4VP@SiO₂对原油的脱镍率和脱钙率分别达到68.4％和62.2％。此外，经过5次电脱盐循环使用过程，P4VP@SiO2对原油中镍和钙均保持了初始脱除能力的95%。因此，吡啶基聚合物刷是一种应用前景广阔、对镍和钙具有高吸附容量的非酸性和可再生原油脱金属剂。

Study on Crude Oil Metal Removal Mechanism of Pyridine Polymer Brush With High Adsorption Capacity

Through silane coupling and free radical polymerization, using SiO₂ as core and poly4-vinylpyridine(P4VP) as shell, polymer brush with core-shell structure (P4VP@SiO2) was designed and synthesized. The structure of P4VP@SiO2 was further characterized by Fourier transform-infrared spectrometer (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and transmission electron microscope (TEM). Impacts of electric desalination process conditions on nickel and calcium removal ratio were investigated. P4VP@SiO₂ regeneration was also studied, and polymer brush metal removal mechanism from crude oils was further proposed. It was found, with P4VP@SiO₂ concentration and settling time increase, nickel and calcium removal ratios increase in the beginning and then can be stabilized. However, with the increase of water/oil mass ratio, mixing intensity, electric desalination temperature and electric field strength, nickel and calcium removal ratios increase in the beginning, but then decrease if the above parameters continue to be increased. Experimental results show that, under the conditions of P4VP@SiO₂ 6000 μg/g, water/oil mass ratio 0.15, emulsified shear intensity 8 kr/min, electric desalination temperature 120 ℃, low-voltage field strength of electric desalting 500 V/cm, high-voltage field strength 1000 V/cm and settling time 60 min, nickel and calcium removal ratios can be as high as 68.4% and 62.2%, respectively. Especially, after five times electric desalination-desorption recycle processes, P4VP@SiO₂ can still demonstrate still very stable property and maintain 95% nickel and calcium removal ratio. The above experimental results indicate that P4VP@SiO₂ is a non-acidic, recyclable, economic crude oil demetallizing agent with high nickel and calcium absorption capacity.