固体防垢块中的HEDP粉末的制备

用固体防垢块防止油井结垢，有效期长。为筛选制作这种固体块所需的材料，评价了7种膦酸盐防垢剂，发现羟基乙叉二瞵酸(HEDP)对碳酸钙垢具有较高的防止能力，且热稳定性好。将HEDP防垢剂水溶液由一定浓度的NaOH中和后，经烘干、粉碎，可制得水溶性好、防垢率高的HEDP钠盐粉末；另一种方法是在HEDP水溶液中按n(Ca(OH)₂)/n(HEDP)=1.75的比例加入Ca(OH)₂，经过滤、烘干后，可得到能在水中缓慢溶解的HEDP粉末，其主要成分是Ca₂HEDP。上述两种HEDP粉末同聚乙烯混炼，可制备出固体防垢块。

THE PREPARATION OF HEDP PHOSPHONATE POWDER USED IN SOLID SCALE INHIBITOR

The scaling in oil well can be effectively prevented for a longer time by using solid inhibitor. To select the inhibitor component used to produce solid inhibitor, 7 types of phosphonate scale inhibitors are evaluated, and HEDP is proved to be most effective and have a rather good properity of heatstability. From the solution of HEDP, HEDP powder can be obtained by the method proposed in the paper. One method is to neutralize the solution of HEDP with a certain concentration of NaOH, then desiccate and grind the resultant. The obtained phosphonate powder is easy to dissolve in water. Another method is to add Ca(OH)₂ into the solution of HEDP with a ratio of n(Ca(OH)₂)/n(HEDP)=1.75. After filtration, desiccation and grinding, another king of phosphonate powder, able to dissolve slowly in water, is gotten. The elemental analysis results confirm that the main constitute of the powder is Ca₂HEDP. These two types of HEDP powder can be used to prepare solid scale inhibitor by mixing with polythene.