石油学报(石油加工) ›› 2021, Vol. 37 ›› Issue (1): 55-66.doi: 10.3969/j.issn.1001-8719.2021.01.006

• 研究报告 • 上一篇    下一篇

短链二烷基多硫的热裂解

吴明清,吴晓颖,潘罗奇,曾光乐,李涛   

  1. 1. 中国石化 石油化工科学研究院, 北京 100083;
    2. 中国石化 大连石油化工研究生,辽宁 大连 116045;
    3. 中国石化 巴陵分公司,湖南 岳阳 414014
  • 收稿日期:2019-12-03 修回日期:2020-07-17 出版日期:2021-01-25 发布日期:2021-01-12
  • 通讯作者: 吴明清,男,教授级高级工程师,博士,从事石油产品质量及改质工艺的研究,E-mail:wumq.ripp@sinopec.com E-mail:wumq.ripp@sinopec.com
  • 基金资助:

    中国石油化工集团公司基金项目(117011-2)资助

Pyrolysis of Short-Chain Dialkyl Polysulfides

WU Mingqing, WU Xiaoying, PAN Luoqi, ZENG Guangle, LI Tao   

  1. 1. Research Institute of Petroleum Processing, SINOPEC, Beijing 100083, China;
    2. Dalian Research Institute of Petroleum and Petrochemicals, SINOPEC, Dalian 116045, China;
    3. Baling Petrochemical Company, SINOPEC, Yueyang 414014, China
  • Received:2019-12-03 Revised:2020-07-17 Online:2021-01-25 Published:2021-01-12

摘要: 以90~120 ℃石油醚为模拟轻烃,以二甲基二硫、二乙基二硫、二叔丁基二硫、二甲基三硫和二乙基三硫为代表性二烷基多硫,在高压反应釜内进行轻烃中微量多硫的热裂解反应,考察反应条件对二烷基多硫的热裂解反应的影响,并采用气相色谱测定二烷基多硫的热裂解产物。结果表明:反应温度、反应压力显著影响短链二烷基多硫的热裂解反应;二烷基多硫的热裂解产物主要是硫醇、H2S和二烷基硫醚;二烷基三硫先歧化反应生成二烷基二硫及二烷基四硫后继续裂解;相同烷基的二烷基多硫分子中硫原子数越多,或相同硫原子数的二烷基多硫分子的烷基越大,硫化物的热稳定性越差。在压力为1.0 MPa时,二甲基二硫、二甲基三硫、二叔丁基二硫的热裂解起始温度分别为213、161及 143 ℃。升高温度可促进热裂解反应,当反应温度由210 ℃(关联压力1.2 MPa)升至330 ℃(关联压力6.5 MPa)时,二甲基二硫热裂解率可由0升为95%以上;当反应温度由120 ℃(关联压力0.20 MPa)升至310 ℃(关联压力5.3 MPa)时,二甲基三硫在120 min内的热裂解率可由0升至95%。增大压力可抑制烷基多硫的热裂解反应,在290 ℃下当反应压力由3.3 MPa升至4.7 MPa时,二甲基二硫在120 min内的热裂解率由90%降至25%;在210 ℃下当反应压力由1.2 MPa升至2.4 MPa时,二甲基三硫在120 min内的热裂解率由36%降至0。调整反应温度和压力,可在一定程度上控制二烷基多硫的热裂解反应程度及产物分布。

关键词: 二烷基多硫, 热裂解, 热稳定性, 硫形态

Abstract: Petroleum ether (90-120 ℃) was selected as solvent for different dialkyl polysulfides, i.e., dimethyl disulfide, diethyl disulfide, di-tert-butyl disulfide, dimethyl trisulfide and diethyl trisulfide. All of above sulfides were employed as model compounds for Short-Chain dialkyl polysulfides pyrolysis study. Thermal cracking experiments were performed in an autoclave. Gas chromatograph with sulfur chemiluminescence detection(GC-SCD)was utilized to determine pyrolyzed sulfur compounds distribution. Experimental results show that temperature and pressure affect dialkyl polysulfides pyrolysis reactions significantly. Mercaptans, hydrogen sulfide and dimethyl sulfide are main pyrolysis products. Dialkyl trisulfides are first disproportionated to dialkyl disulfides and dialkyl tetrasulfides, and then both of them continue to pyrolyze into smaller molecule sulfides. Polysulfides with same alkyls but more sulfur atoms or with the same sulfur atoms but longer alkyl chain are relatively easy to pyrolyze. Initial pyrolysis temperatures of dimethyl disulfide, dimethyl trisulfide and di-tert-butyl disulfide at 1.0 MPa are 213, 161 and 143 ℃, correspondingly. Higher temperature can favor pyrolysis reactions. For example, for dimethyl disulfide, pyrolysis ratio can increase from 0 to more than 95% in 120 min when reaction temperature increases from 210 ℃(under pressure of 1.2 MPa) to 330 ℃(under pressure of 6.5 MPa). Higher pressure can inhibit the pyrolysis reactions. For example, pyrolysis ratio of dimethyl disulfide can decrease from 90% to 25% in 120 min when reaction pressure increases from 3.3 MPa to 4.7 MPa at 290 ℃. Pyrolysis ratio of dimethyl trisulfide can decrease from 36% to 0 in 120 min when pressure increases from 1.2 MPa to 2.4 MPa at 210 ℃. With changing temperature and pressure, pyrolysis product of Short-Chain dialkyl polysulfides might can be managed.

Key words: dialkyl polysulfide, pyrolysis, thermal stability, sulfur type