天然气处理厂循环水系统阻垢缓蚀机理及优化设计

发布时间：2018-12-25 08:45

【摘要】：某液化天然气厂在投产不到一年后,换热器发生了严重的腐蚀穿孔。经过分析发现,这是由于循环冷却水系统换热器发生严重的结垢而引起了垢下腐蚀,最终导致了换热器穿孔报废。所以本文旨在研究阻垢缓蚀剂的作用机理,并对工厂的阻垢剂进行优化筛选,以达到控制换热器结垢与腐蚀的目的。本文利用雷兹纳稳定指数法对补充水的水质进行了判定,R.S.I值为6.74,因此判断工厂的补充水属于腐蚀性水质。利用碳酸钙沉积法研究QD-681A的阻垢机理,发现聚丙烯酸类阻垢剂符合晶格畸变理论和再生-自解脱膜假说。采用碳酸钙沉积法对QD-681A、QD-632A、QD-631-5A、QD-655四种药剂的阻垢性能进行了评价。实验结果表明:药剂单一作用时,QD-655阻垢率最高,QD-681A的阻垢率最低;复配使用时,QD-632A与QD-631-5A在4:1的比例下阻垢率最高。药剂的质量浓度增大时,QD-681A的阻垢率升高,QD-655的阻垢率略有降低;随着温度的升高,药剂的阻垢率降低;Ca2+浓度增大时,QD-681A的阻垢率先升高后降低,QD-655的阻垢率逐渐降低;随着HCO3-浓度的增大,药剂的阻垢性能降低;随着p H值的增大,药剂的阻垢率降低。
[Abstract]:Less than a year after a LNG plant was put into operation, the heat exchanger was corroded and perforated seriously. Through analysis, it is found that the heat exchanger of circulating cooling water system has serious fouling and resulting in the corrosion under the scale, which eventually leads to the perforation of the heat exchanger and the scrapping of the heat exchanger. The purpose of this paper is to study the action mechanism of scale and corrosion inhibitor and to optimize and screen the scale inhibitor in order to control the scaling and corrosion of heat exchanger. In this paper, the Rezner stability index method is used to determine the water quality of recharge water. The R.S.I value is 6.74, so it is judged that the recharge water in the factory belongs to corrosive water quality. The scale inhibition mechanism of QD-681A was studied by means of calcium carbonate deposition. It was found that the scale inhibitor of polyacrylic acid was in accordance with lattice distortion theory and the hypothesis of regeneration-self-debridement film. The scale inhibition of QD-681A,QD-632A,QD-631-5A,QD-655 was evaluated by calcium carbonate deposition method. The experimental results show that the scale inhibition rate of QD-655 is the highest, and that of QD-681A is the lowest, and that of QD-632A and QD-631-5A is the highest at 4:1. The scale inhibition rate of QD-681A increased and the scale inhibition rate of QD-655 decreased slightly with the increase of mass concentration, and the scale inhibition rate decreased with the increase of temperature. When the concentration of Ca2 increased, the scale inhibition of QD-681A increased first and then decreased, and the scale inhibition rate of QD-655 decreased gradually; with the increase of HCO3- concentration, the scale inhibition performance of the reagent decreased; with the increase of pH value, the scale inhibition rate of the agent decreased.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE685.3

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