Study on the transformation rule of different long chain alkane hydroisomerization over Pt/SAPO-11 catalyst
-
摘要: 采用SAPO-11分子筛制备的双功能催化剂, 以碳链长度为10-14的正构烷烃为模型化合物, 探索了不同碳数的长链正构烷烃临氢转化反应规律。结果表明, 低温下不同碳数的正构烃都表现出较高的异构化选择性, 改变反应温度使反应转化率控制在85%以下时, 正构烷烃的异构化选择性可以达到90%左右; 随着碳数和温度升高, 正构烷烃由于发生明显的裂化反应导致转化率提高和异构化选择性降低。采用SAPO-11分子筛催化材料的双功能催化剂具有明显的产物择形异构效应, 异构化产物以甲基位于端位和碳链中心的单侧链异构体为主, 双(多) 支链产物较少。长链正构烷烃在Pt/SAPO-11催化剂上的裂化反应在低转化率以加氢裂化为主, 裂化产物的碳数呈均匀分布; 在高转化率下以酸催化裂化为主, 裂化产物的碳数分布呈现明显的不对称分布特征。Abstract: The reaction mechanism of hydroisomerization of n-alkanes, from n-decane to n-tetrodecane, over Pt/SAPO-11 catalyst was studied. Results indicated that the n-alkanes with different carbon atom numbers exhibited higher isomerization selectivity at lower temperatures. The isomerization selectivity of n-alkanes can reach 90% by controlling temperature to keep the conversion rate lower than 85%. The conversion rate of n-alkanes was increased and the selectivity of isomerization was decreased with the increase of carbon atom number and temperature due to the occurrence of cracking reaction. Bifunctional catalyst has a good product shape selective effects. The isomerization products are mainly composed of unilateral chain isomers which have the methyl at the end and the center of the carbon chain. At low conversion rate, the cracking reaction of the long-chain n-alkanes over the Pt/SAPO-11 catalyst was mainly catalytic hydrocracking, the carbon number distribution of the cracking products was uniform. However, at high conversion rate, the reaction was mainly acid catalytic cracking, the carbon number distribution of cracking products was obvious asymmetric distribution.
-
Key words:
- hydroisomerization /
- long chain n-alkane /
- SAPO-11 /
- isomerization selectivity
-
图 1 不同碳链对异构化反应活性的影响
Figure 1 Influence of different carbon chain on the isomerization reaction activity
(a): conversion; (b): cracking; (c): selectivity
■: 300 ℃; ●: 320 ℃; ▲: 340 ℃; ▼: 360 ℃; ◆:380 ℃
图 2 正构烷烃在Pt/SAPO-11催化剂上加氢异构化反应网络
Figure 2 Hydro-isomerization network of n-alkanes over Pt/SAPO-11 catalyst
图 3 不同碳链正构烷烃在转化率为45%-50%下的甲基支链异构体分布
Figure 3 Distribution of methyl-branched isomers obtained at 45%-50% conversion of n-alkanes with different carbon chain
图 4 温度对不同碳链产物分布的影响
Figure 4 Influence of temperature on the product distribution of the different carbon chain
(a): n-decane; (b): n-undecane; (c): n-dodecane; (d): n-tridecane; (e): n-tetradecane
图 5 不同碳链正构烷烃转化率与异构化选择性的关系
Figure 5 Relationship between n-alkane conversion and isomerization selectivity
图 6 正癸烷临氢异构化反应产物分布与转化率的关系
Figure 6 Relationship between product distribution and conversion of C10 isomerization
图 7 不同转化率下正癸烷裂解产物的碳数分布
Figure 7 Carbon-number distribution in hydrocracked products of n-decane at different conversion
图 8 不同链长正构烷烃裂解产物的碳数分布
Figure 8 Carbon-number distribution in hydrocracked products of n-alkanes with different carbon numbers
表 1 不同链长正构烷烃对产物分布的影响
Table 1 Influence of different carbon chain on product distribution
C10 C11 C12 C13 C14 LM WM w(Me-C)/% 75.11 65.13 70.08 42.55 54.31 74.86 56.05 w(DM-C)/% 11.29 7.88 14.29 34.70 11.57 9.62 12.65 (LM, WM were light and heavy mixed liquid wax) 
下载: 导出CSV
-
[1] MILLER S J. New molecular sieve process for lube dewaxing by wax isomerization[J]. Microporous Mater, 1994, 2(5): 439-449. doi: 10.1016/0927-6513(94)00016-6 [2] MILLER S J. Studies on wax isomerization for lubes and fuels[J]. Stud Sur Sci Catal, 1994, 84: 2319-2326. doi: 10.1016/S0167-2991(08)63796-9 [3] BRENMAN J A.Wide-temperature range synthetic hydrocarbon fluids[J]. Ind Chem Prod Res Dev, 1980, 19(1): 2-6. doi: 10.1021/i360073a002 [4] 水天德.现代润滑油生产工艺[M].北京:中国石化出版社, 1997: 29-37.SHUI Tian-de. Modern oil production process[M]. Beijing: China Petrochemical Press, 1997: 29-37. [5] 刘维桥, 刘平, 任杰, 孙予罕.正构烷烃临氢异构化反应研究进展[J].精细石油化工进展, 2007, 8(10): 19-26. http://www.cnki.com.cn/Article/CJFDTOTAL-JXSI200710009.htmLIU Wei-qiao, LIU Ping, REN Jie, SUN Yu-han. Advances in research of n-paraffin hydroisomerization[J]. Adv Fine Petrochem, 2007, 8(10): 19-26. http://www.cnki.com.cn/Article/CJFDTOTAL-JXSI200710009.htm [6] 刘维桥, 尚通明, 崔益梅. Pt (Pd)/SAPO-11的正庚烷临氢异构化反应特性[J].江苏技术师范学院学报, 2008, 14(1): 1-5. http://www.cnki.com.cn/Article/CJFDTOTAL-CZJF200801001.htmLIU Wei-qiao, SHANG Tong-ming, CUI Yi-mei. Characteristics of heptane hydroisomerization over Pt (Pd)/SAPO-11 catalyst[J]. J Jiangsu. Teach Univ Technol, 2008, 14(1): 1-5. http://www.cnki.com.cn/Article/CJFDTOTAL-CZJF200801001.htm [7] MÉRIAUDEAU P, TUAN V A, NGHIEM V T, LAI S Y, HUNG L N, NACCACHE C. SAPO-11, SAPO-31 and SAPO-41 molecular sieves: Synthesis, characterization, and catalytic properties in n-octane hydroisomerization[J]. J Catal, 1997, 169(4): 55-66. https://www.researchgate.net/publication/238644903_SAPO-11_SAPO-31_and_SAPO-41_Molecular_Sieves_Synthesis_Characterization_and_Catalytic_Properties_in_n-Octane_Hydroisomerization [8] 耿承辉, 张飞, 高志贤, 周敬来, 任杰. Pt/SAPO-11催化剂上长链烷烃临氢异构化产物分布规律的研究[J].石油学报(石油加工), 2005, 2: 16-22. http://www.cnki.com.cn/Article/CJFDTOTAL-SXJG200502002.htmGEN Cheng-hui, ZHANG Fei, GAO Zhi-xian, ZHOU Jing-lai, REN Jie. Study on the production distribution of long chain alkane hydroisomerization over Pt/SAPO-11 catalyst[J]. Acta Pet Sin (Pet Process Sec), 2005, 2: 16-22. http://www.cnki.com.cn/Article/CJFDTOTAL-SXJG200502002.htm [9] CAMPELO J M, LAFONT F, MARINAS J M. Comparison of the acrivity and selectivity of Pt/SAPO-5 and Pt/SAPO-11 in n-hexane and n-heptane hydroconvertion[J]. Appl Catal, 1997, 152(1): 53-62. doi: 10.1016/S0926-860X(96)00347-X [10] CAMPELO J M, LAFONT F, MARINAS J M. Hydroconversion of n-dodecane over Pt/SAPO-11 catalyst[J]. Appl Catal, 1998, 170(1): 139-144. doi: 10.1016/S0926-860X(98)00036-2 [11] SINHA A K, SIVASANKER S, RATNASAMY P. Hydroisomerization of n-alkanes over Pt-SAPO-11 and Pt-SAPO-31 synthesized from aqueous and nonaqueous media[J]. Ind Eng Chem Res, 1998, 37(6): 2208-2214. doi: 10.1021/ie9707228 [12] 高志贤, 耿承辉, 张飞, 李源.一种长链正构烷烃临氢异构化催化剂及其应用方法[P].中国, 03145688.X. 2004-02-18.GAO Zhi-xian, GENG Chen-hui, ZHANG Fei, LI Yuan. A long-chain n-alkanes hydroisomerization catalyst and application method: CN, 03145688. X[P]. 2004-02-18. [13] 张志华, 胡胜, 韩雪莲, 许本静, 田永亮, 阎子峰. Pt/SAPO-11催化剂上柴油馏分临氢异构化改质反应研究[J].分子催化, 2005, 5: 20-25. http://www.cnki.com.cn/Article/CJFDTOTAL-FZCH200505002.htmZHANG Zhi-hua, HU Sheng, HAN Xue-lian, XU Ben-jing, TIAN Yong-liang, YAN Zi-feng. Study on hydroisomerization of diesel fuel over Pt/SAPO-11[J]. J Mol Catal, 2005, 5: 20-25. http://www.cnki.com.cn/Article/CJFDTOTAL-FZCH200505002.htm [14] CLAUDE M C, MARTENS J A. Monomethyl branching of long n-alkanes in the range from decane to tetracosane on Pt/HZSM-22 Bi-function catalyst[J]. J Catal, 2000, 190(1): 39-48. doi: 10.1006/jcat.1999.2714 [15] MARTENS J A, VANBUTSELE G, JACOBS P A, DENAYER J, OCAKOGLU R, BARON G, MUNOZ ARROYO J A, THYBAUT J, MARIN G B. Evidences for pore mouth and key-lock catalysis in hydroisomerization of long n-alkanes over 10-ring tubular pore bifunctional zeolites[J]. Catal Today, 2001, 65(2): 111-116. http://www.academia.edu/14026190/Evidences_for_pore_mouth_and_key_lock_catalysis_in_hydroisomerization_of_long_n-alkanes_over_10-ring_tubular_pore_bifunctional_zeolites [16] WEITKAMP J. Isomerization of long-chain n-alkanes on a Pt/CaY zeolite catalyst[J]. Ind Eng Chem Prod Res Dev, 1982, 21(4): 550-558. doi: 10.1021/i300008a008 [17] CAMPELO J M, LAFONT F, MARINAS J M. Hydroconversion of n-dodecane over Pt/SAPO-11 catalyst[J]. Appl Catal A: Gen, 1998, 170: 139-144. doi: 10.1016/S0926-860X(98)00036-2 -
点击查看大图
计量
- 文章访问数: 111
- HTML全文浏览量: 55
- PDF下载量: 6
- 被引次数: 0
