CIESC Journal ›› 2022, Vol. 73 ›› Issue (2): 894-903.DOI: 10.11949/0438-1157.20211023

• Energy and environmental engineering • Previous Articles     Next Articles

Study on a biodegradable kinetics hydrate inhibitor

Li WAN1,2,3(),Deqing LIANG1,2,3()   

  1. 1.Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, Guangdong, China
    2.CAS Key Laboratory of Gas Hydrate, Guangzhou 510640, Guangdong, China
    3.Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, Guangdong, China
  • Received:2021-07-22 Revised:2021-09-26 Online:2022-02-18 Published:2022-02-05
  • Contact: Deqing LIANG

一种可生物降解水合物动力学抑制剂的研究

万丽1,2,3(),梁德青1,2,3()   

  1. 1.中国科学院广州能源研究所,广东 广州 510640
    2.中国科学院天然气水合物重点实验室,广东 广州 510640
    3.广东省新能源和可再生能源研究开发与应用重点实验室,广东 广州 510640
  • 通讯作者: 梁德青
  • 作者简介:万丽(1986—),女,博士研究生,讲师,511346798@qq.com
  • 基金资助:
    广东省区域联合基金-青年基金项目(2020A1515110698);中国科学院天然气水合物重点实验室项目(E129020301)

Abstract:

Water-soluble polymers such as poly-vinylpyrrolidone (PVP), poly-vinylcaprolactam (PVCap), and Gaffix VC-713 are predominantly used as kinetic hydrate inhibitors (KHIs) in the natural gas industry to control the formation of hydrates. However, their industrial application was limited because of low biodegradability. Therefore, developing environment-friendly, biodegradable inhibitors is necessary. In this paper, readily biodegradable sodium alginate and the monomer of PVCap were copolymerized to synthesize NaAlg-g-PVCap, a new hydrate kinetic inhibitor. Its hydrate inhibition performances was investigated through the maximum subcooling and gas consumption, as well as the biodegradability evaluated through the value of BOD5/COD. The results showed that the maximum subcooling of NaAlg-g-PVCap system at low concentration (0.25%(mass)) was better than PVP K90, but lower than PVCap, and its value decreased slightly with the increased concentration. Below the maximum subcooling (ΔTsub=5℃), NaAlg-g-PVCap showed both nucleation and growth inhibition effects. The initial growth rate of hydrate of NaAlg-g-PVCap system was only about 1/10 of the pure water system, also much higher than PVP systems. Meanwhile, the addition of NaAlg-g-PVCap reduced the gas consumption of the system over 60% compared with that of pure water/PVP system, close to PVCap system. However, the nucleation inhibition effect of NaAlg-g-PVCap decreased significantly with the increase of subcooling, which may be the result of the interaction of two segments in the copolymer. The biodegradability of NaAlg-g-PVCap was 26% higher than that of PVCap, tended to be easily degraded. It shows that the copolymerization of PVCap and NaAlg optimizes the overall performance, showing better hydrate inhibition performance and biodegradability.

Key words: sodium alginate, vinyl-caprolactam, hydrate inhibitor, biodegradability

摘要:

目前用于天然气水合物防治的工业动力学抑制剂主要是水溶性聚合物,如聚乙烯基吡咯烷酮(PVP)、聚乙烯基己内酰胺(PVCap)、Gaffix VC-713等,然而生物降解性低限制了其工业应用。因此,开发环保型的抑制剂具有重要意义。实验采用易生物降解的海藻酸钠与PVCap的单体接枝共聚,合成一类新型水合物动力学抑制剂NaAlg-g-PVCap,结合最大过冷度及耗气量评价了新型抑制剂在水合物生成过程中的抑制性能,并通过BOD5/COD值评价了新型抑制剂的生物降解性。结果表明低剂量[0.25%(质量)]下NaAlg-g-PVCap的最大耐受过冷度优于PVP K90,但低于PVCap,且随着添加剂量增大而微弱降低;在其最大耐受过冷度以下(ΔTsub=5℃),NaAlg-g-PVCap表现出较好的水合物成核和生长抑制作用,其体系水合物初始生长速率值约只为纯水体系的 1/10,也远高于PVP体系,且总耗气量相比纯水及PVP体系减少了60%以上,与PVCap体系接近,但随着过冷度增大,NaAlg-g-PVCap成核抑制作用下降明显,这可能是共聚物中两部分共同作用的结果;同时,NaAlg-g-PVCap相比PVCap其生物降解性提高了26%, 倾向于易降解。说明PVCap与NaAlg共聚后优化了整体的性能,表现出较好的水合物抑制性能和生物降解性。

关键词: 海藻酸钠, 乙烯基己内酰胺, 水合物抑制剂, 生物降解性

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