醋酸水溶液用作脱钙剂的研究

STUDY ON THE DECALCIFICATION BY AQUEOUS ACETIC ACID

用稀醋酸水溶液作为脱钙剂,环烷酸钙作为模型有机钙化合物,研究了反应条件以及原油三组分的存在对脱钙的影响。结果表明,在24～40℃范围内,随温度升高,脱钙率明显增大;温度在40～60℃之间时,脱钙率变化不大。原油三组分对钙的脱除有一定影响,其中,沥青质影响最大,其次是胶质;饱和分和芳香分单独存在时对脱钙影响不大,但与胶质、沥青质共存时,对胶质、沥青质的不良影响有一定的抑制作用。适当增加酸处理次数,能够较好地克服胶质、沥青质等对脱钙造成的不良影响,提高脱钙率。在样剂比为10∶4,反应温度为50℃,每次反应时间为10 min,水洗3次,酸处理4次的条件下,总脱钙率可达98．4%,剩余钙含量降至1．40 mg/L。

The influences of reaction conditions and petroleum fractions on the removal of calcium by dilute aqueous acetic acid were investigated using calcium naphthenate as model compound. The test results showed that the calcium removal rate increased with the reaction temperature in the range of 24-40 ℃ ,and it kept constant in the temperature range of 40-60℃. The calcium removal rate was strongly affected by the existence of petroleum fractions,in the order from high to low,asphaltene, secondary resin, saturates and aromatics. The presence of saturates and aromatics could suppress the negative effect of asphaltene and resin on calcium removal in some extent. Higher removal rate was obtained by multiple acid treatments. A calcium removal rate of 98.4 % could be reached after 4 repeated acid treatments under the conditions of a volume ratio of treated sample/acid solution of 2.5,a reaction temperature of 50 ℃, and a reaction time of 10 rain followed by triple-rinse with water. The calcium content of the treated sample was reduced to 1. 40 mg/L from the original 87.24 mg/L with said treatment.