材料类型对CaCO3析晶污垢生长特性的影响机理研究

目的 针对油田集输系统结垢情况严重、易造成管线堵塞的问题，基于集结聚垢除垢法，研究不同材料类型对碳酸钙析晶污垢的促进效应。方法 采用动态模拟剪切实验，以镀锌铁、铝、13Cr不锈钢、316L不锈钢、H62黄铜和H59黄铜6种材料为研究对象，分析CaCO3晶体在不同材料表面的结垢特性。并通过SEM、XRD和EDS测试，探究不同材料表面吸附晶体的晶型晶貌、晶粒分布和元素组成，从而揭示材料类型对析晶污垢生长特性的影响机理。结果 材料类型对以CaCO3为主的析晶污垢的生长特性有较为显著的影响。镀锌铁表面的结垢量最大且形成了层状垢，反应36 h时，其结垢量达88.8 mg；13Cr不锈钢表面的结垢量最小且仍以颗粒的形式分布，反应36 h时，结垢量为-1.7 mg。镀锌铁长时间的失钙率最高，反应36 h时，达9.49%；H59黄铜的失钙率始终最低，反应36 h时，仅为4.77%。结论 析晶污垢在材料表面的分布形式和氧化反应结果是污垢生长特性产生较大差异的主要机制：层状垢将促进结垢，而颗粒垢则会抑制结垢。此外，材料表面的氧化反应对结垢的影响具有双重性，若形成致密的氧化薄层，会阻碍后续结垢；反之，若形成混合垢层，则促进结垢。

Effect Mechanism of Material Type on Crystallization Growth of CaCO3-based Scale

The work aims to study the promoting effect of different materials on the crystallization of calcium carbonate by the aggregated scale removal method so as to settle the serious scale formation of gathering system and pipeline-clogging in the oil field. Galvanize iron, aluminum, 13Cr stainless steel, 316L stainless steel, H62 brass and H59 brass were used as the research objects in the dynamic simulation shear test to analyze the scale-formation characteristics of CaCO3 crystal on the surfaces of these different materials. SEM, XRD and EDS were used to study the crystalline morphology, grain distribution and elemental composition of deposited crystalline on the surfaces and then explore the mechanism how material type influenced the crystalli-zation growth. Material type had a great effect on the crystallization growth of CaCO3-based scale formation. The scale on the surface of galvanized iron was present as the layer scale with the largest volume (88.8 mg after 36 hours). The scale on the surface of 13Cr stainless steel was present in the form of particles with the smallest volume (-1.7 mg after 36 hours). The long-term calcium loss rate of galvanized iron was the highest (9.49% after 36 hours), and that for H59 brass was the lowest (4.77% for 36 hours). The distribution pattern of crystallization fouling on the surface of different materials and the oxidation reaction are main mechanisms for the great diversity in the growth characteristic of the scale. Layered scale can boost scale formation while grain scale acts as inhibitors for scale formation. Oxidation reaction on the surface has dual effect on the scale formation and a dense layer of oxide can prevent subsequent scale formation, while mixed scale is an activator for subsequent scale formation.