Study On Preparation And Properties Of Anti-hydrating Coatings

In this works,the problem of hydrate blockage is able to be solved by preparing the hydrophobic coating based on the mechanism of hydrate clogging.The coatings were characterized by scanning electron microscopy?SEM?,contact angle measurement and adhesion test.The adhesive force between hydrate particles and coatings was investigated by using micro-manipulation technology,and the effect of coatings on the adhesion force of hydrate particles was discussed from the microscopic point of view.In addition,the nucleation temperature of hydrate on the coating,the nucleation time at specified temperature and the growth experiment of hydrate on the coating were investigated in a jacketed reactor.In this work,anti-hydrating coatings were successfully fabricated by dip-coating using PTFE as low surface energy material,hydrophobic nano-SiO₂ for constructing roughness,or polyphenylene sulfide?PPS?as composite material and ethanol as cosolvent.Two groups of coatings?group A and group B?were produced in this project:the raw materials of group A were PTFE and SiO₂;the raw materials of group B were PTFE,PPS and SiO₂.The characterization results show that the coatings of group A are both hydrophobic and have good adhesion.When the content of SiO₂ is 0.8g,the surface of the coating is relatively rough,and the contact angle reaches a maximum of 134.3°,and the adhesion of the coating is1 grade.When the content is less than 0.8g,the surface of the coatings is relatively smooth,the minimum contact angle is 113.9°,and the adhesion of all coatings is 0;the coatings of group B all show good hydrophobicity,the contact angle of all coatings is more than 146°,and the PTFE content has no obvious influence on the contact angle.The surface of the coatings has a concave-convex structure.When the PTFE content is 5g or 10g,the coatings surface will be cracked and the coatings will be destroyed,in this case,the coatings adhesion is only 5 grade;when the PTFE content is more than 10g,the coatings are stable,adhesion level reach 2 grade.The coating can reduce the adhesion between the hydrate particle and the substrate.The adhesive force between group A coatings and hydrate particle was 23.8%to 68.6%of the adhesion between hydrate particle and X65 substrate.With the content increase of SiO_2,the adhesion of coatings also increased.In the test of group B,all of coatings adhesive force was0N/m,and the PTFE content has no significant effect on adhesive force.The hydrate nucleation temperature on X65 substrate is-11.2°C.Compared with the bare substrate,the nucleation temperature reduction range of group A and group B is45.5%-66.1%and 79.5%-83.9%,respectively;at-10°C,the nucleation extension time range is 32.5%-74.5%and 96.2%-188.1%,respectively.When SiO₂ is 0.8g in the coating of group A and PTFE content is 15g in the coating of group B,the nucleation temperature reduction and the nucleation time prolongation achieve the best results in two groups of experiments at the temperature of-10°C and-15°C,and in the hydrate growth experiment at 6°C,the hydrate growth rate is the slowest and the growth time is the longest.From the experimental results,it is known that the coating compositions with the best performance of the anti-hydrating compound in the coatings of group A and group B is10gPTFE?0.8gSiO₂ and 15gPTFE?10gPPS?0.5gSiO₂,respectively.And the performance of group B coatings is better than that of group A coatings.