抽提-离子色谱法测定原油中无机阴离子含量

Determination of inorganic anions in crude oil by extration-ion chromatogrophy

陕北油田子长区块原油乳状液破乳剂脱水难度较其他区块大得多。为了分析陕北原油中无机盐对破乳剂脱水过程等的影响,找到能同时测定原油中多个可溶性无机盐阴离子含量的有效方法,取该油田崔圪崂12井、碾庄107井、碾庄206井、子长2井、子长1006井原油做样品,将其溶于二甲苯,再用乙醇、丙酮和水在指定的抽提器中对所含无机盐进行抽提。抽提液用ICS-900离子色谱仪测定其氟离子、氯离子、溴离子、亚硝酸根、硝酸根、硫酸根和磷酸根的含量,用AS9-HC型阴离子分析柱作交换柱,4.5×10^(-3)mol·L^(-1)碳酸钠-8.0×10^(-4)mol·L^(-1)碳酸氢钠溶液作淋洗液。实验表明,陕北原油中无机盐主要是氯化物,崔圪崂12、碾庄107、碾庄206、子长2、子长1006井原油中氯离子含量依次为324.3μg·g^(-1)、21.83μg·g^(-1)、19.45μg·g^(-1)、2.210×10~4μg·g^(-1)、1.673×10~4μg·g^(-1)。子长原油乳状液脱水困难的原因之一可能是其中的氯化物和溴化物含量高。6次进样,保留时间的相对标准偏差RSD在0.18%-0.52%之间,无机阴离子含量加标回收率在95.60%~103.0%之间。

The dehydration of crude oil emulsions from Zi Chang block by demulsifier are more difficultthan others in the Northern Shaanxi oil field.In order to analyze the effect of inorganic salts in the crude oils on the dehydration of crude oil emulsion by demulsifier and find an effective method for simultaneous determination of multiple soluble inorganic salt anions in crude oil,the representative crude oils from Cui Ge Lao 12 well,Nian Zhuang 107 well,Nian Zhuang 206 well,Zi Chang 2 well,Zi Chang 1006 well in Northern Shaanxi oil field were respectively dissolved in xylene,andthe inorganic salts were extracted by ethanol,acetone and water from the solutions of the crude oils in xylene.The contents of fluoride,chloride,bromide,nitrite,nitrate,sulfate and phosphate in the inorganic salt solutions are determined by ICS-900 ion chromatograph.AS9-HCanionic analysis column is used as ion exchange column,and a mixture of 4. 5 ×10^-3mol·L（-1）sodium carbonate-8. 0×10^-4mol·L（-1）sodium bicarbonate is used as eluent.It is indicated by experiment that the inorganic salts in North Shaanxicrudeoil are mainly chlorides and its contents in crude oils of Cui Ge Lao 12 well,Nian Zhuang 107 well,Nian Zhuang 206 well,Zi Chang 2 well,Zi Chang 1006 well are 324. 3μg · g^-1,21. 83μg·g^-1,19. 45μg·g^-1,2. 210×10^4μg·g-1,1. 673×10^4μg·g^-1respectively,and It is also indicated that One of the reasons that dehydration of the crude oil emulsion from Zi Chang block is more difficult than otherscan beits higher contents of the chloride and bromide than others.For six sample injections,the RSD of retention times is between 0. 18% and 0. 52%,the recovery of inorganic anions is between 95. 60% and 103. 0%.