聚羧酸螯合剂的制备及原油酸性氧化脱有机钙的实验研究

PREPARATION OF POLYCARBOXYLATE CALCIUM CHELATING AGENT FOR ACIDIC OXIDATION REMOVAL OF ORGANIC CALCIUM FROM CRUDE OILS

实验以丙烯酸、马来酸酐、丙烯酰胺为单体,过硫酸钾为引发剂,于70～90℃反应4～6 h,合成一种多酰胺基多羧基聚羧酸螯合剂,并用EDTA标准溶液测定了其钙螯合性能,傅里叶红外光谱仪进行了结构表征。在SH-Ⅱ型电脱盐仪上考察了该螯合剂在弱酸性氧化条件下,对4种原油有机钙脱除效果。实验结果表明,当丙烯酸、马来酸酐、丙烯酰胺单体摩尔比为4:7:2时,对钙的螯合力达99.38 mg/g;经弱酸性氧化剂H_2O_2抽提后,原油中有机钙含量降低16%～20%;在剂钙摩尔比为2.5、温度为125～130℃时,该螯合剂对三种实验原油有机钙的脱除率达75%,同时对Mg、Fe、Ni也可部分脱除。

Using acrylic acid, maleic anhydride and acrylamide as monomers, potassium persulphate as an initiator, a novel polycarboxylate calcium chelating agent containing multi-amide and polycarboxylic groups was prepared at 70 - 90℃ for 4 - 6 h. The calcium chelating capacity was tested with standard EDTA solution and its structure was identified by Fourier transform infrared spectroscopy. With SH- Ⅱ electrical desalter, the performance of removing organic calcium from four different crude oils under the condition of weak acidic oxidation was evaluated. The results indicated that when the molar ratio of acrylic acid, maleic anhydride, and acrylamide was 4 ： 7 ： 2, the calcium sequestering capacity reached 99.38 mg/g; organic calcium content in the crude oils after extracted by weak acidic oxidant H2O2 solution decreased by 16%-20%; more than 75% of the organic calcium from the three tested crude oils was removed with agent/calcium molar ratio of 2.5 at 120 - 130 ℃, accompanied by some elimination of magnesium, iron and nickel metals as well.