Separation of normal hydrocarbons from Fischer-Tropsch synthetic light oil by urea inclusion method

doi:10.16085/j.issn.1000-6613.2022-0607

Abstract

Abstract:

The process conditions of urea inclusion method were studied for the separation of normal and isomeric hydrocarbons in Fischer-Tropsch (F-T) synthetic light oil. The composition of raw oil was analyzed by GC-MS method. The effects of activator type, oil/urea/activator mass ratio, inclusion temperature and time on the separation performance were investigated, and the suitable conditions for the decomposition of urea inclusion compounds were obtained. The optimal inclusion conditions of F-T synthetic light oil were determined through orthogonal experiments, which were m(urea)∶m(methanol)∶m(oil)=5∶6∶1, the terminal temperature 10℃, and the reaction time 120min. Under these conditions, the mass fraction of normal hydrocarbons in the product was 99.43%, and the yield was 38.11%. The inclusion results showed that in the middle and low carbon segments (C₄—C₁₃) of normal hydrocarbons, urea was more inclined to include those with longer carbon chains, with a yield of normal hydrocarbons of C₈ and above higher than 60%, while those below C₆ could be barely included by urea. In addition, when the raw oil contained both olefins and alkanes, the urea inclusion of n-alkanes was better than that of n-alkenes, and the yield difference was about 5.5%. In this oil, oxygenates dominated by linear alcohols were less included by urea, and so more than 95% oxygenate impurities could be removed by urea inclusion method.

Key words: separation, Fischer-Tropsch synthetic light oil, normal hydrocarbons, urea inclusion, purification, hydrocarbons

摘要：

研究了尿素包合方法分离费托轻质油中正构烃和异构烃的工艺条件。本文采用气相色谱-质谱联用的方法分析了原料油组成，考察了活化剂种类、油品/尿素/活化剂质量比、包合温度和时间对分离结果的影响，探索得到了合适的解包合条件。实验所得费托轻质油尿素包合反应的最佳工艺条件为：尿素/甲醇/原料油的质量比为5∶6∶1，反应终温为10℃，反应时间为120min，在此条件下，费托轻质油包合产品中正构烃的质量分数为99.43%，收率为38.11%。实验表明，中低碳数（C₄～C₁₃）段内，尿素更倾向于包合碳链较长的正构烃，C₈及以上正构烃的收率均高于60%，而C₆以下的正构烃难以被尿素包合。在同时含有烯烃和烷烃的原料油中，正构烷烃的包合效果优于正构烯烃，二者收率相差约5.5%。该油品体系中，以直链醇为主的含氧化合物被尿素包合少，95%以上的含氧有机物杂质可通过尿素包合方法除去。

关键词: 分离, 费托轻质油, 正构烃, 尿素包合, 纯化, 烃类化合物

CLC Number:

TQ536.9

WANG Zhe, YU Ying, SHI Yongjie, YANG Shun, CHEN Jiuzhou, CUI Xili, XING Huabin. Separation of normal hydrocarbons from Fischer-Tropsch synthetic light oil by urea inclusion method[J]. Chemical Industry and Engineering Progress, 2023, 42(2): 677-683.

王哲, 余颖, 石永杰, 杨顺, 陈久洲, 崔希利, 邢华斌. 尿素包合法分离费托轻质油中的正构烃[J]. 化工进展, 2023, 42(2): 677-683.

Figures/Tables 10

References 18

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碳原子数	物质质量分数/%
碳原子数	正构烷烃	正构烯烃	正构烃合计	异构烃/含氧化合物合计
C₄	1.25	2.23	3.48	4.3
C₅	5.00	10.92	15.92
C₆	5.52	13.45	18.98
C₇	5.43	14.79	20.22
C₈	4.78	14.51	19.29
C₉	2.63	8.83	11.46
C₁₀	0.98	3.32	4.30
C₁₁	0.36	1.16	1.52
C₁₂	0.10	0.33	0.43
C₁₃	0.04	0.08	0.11
合计	26.1	69.6	95.7

碳原子数	物质质量分数/%
碳原子数	正构烷烃	正构烯烃	正构烃合计	异构烃/含氧化合物合计
C₄	1.25	2.23	3.48	4.3
C₅	5.00	10.92	15.92
C₆	5.52	13.45	18.98
C₇	5.43	14.79	20.22
C₈	4.78	14.51	19.29
C₉	2.63	8.83	11.46
C₁₀	0.98	3.32	4.30
C₁₁	0.36	1.16	1.52
C₁₂	0.10	0.33	0.43
C₁₃	0.04	0.08	0.11
合计	26.1	69.6	95.7

活化剂	包合条件	产品纯度/%	包合收率/%
甲醇	50g尿素+75mL甲醇+20mL水，20℃，120min	98.27	38.64
乙醇	50g尿素+75mL乙醇+20mL水，5℃，60min	98.07	39.38
异丙醇	40g尿素+70mL异丙醇+20mL水，15℃，120min	98.03	41.44

活化剂	包合条件	产品纯度/%	包合收率/%
甲醇	50g尿素+75mL甲醇+20mL水，20℃，120min	98.27	38.64
乙醇	50g尿素+75mL乙醇+20mL水，5℃，60min	98.07	39.38
异丙醇	40g尿素+70mL异丙醇+20mL水，15℃，120min	98.03	41.44

实验号	因素					产品纯度/%	包合收率/%
实验号	A包合剂量/g	B活化剂量/mL	C溶剂量/mL	D包合温度/℃	E包合时间/min	产品纯度/%	包合收率/%
1	1（45）	1（55）	1（0）	1（5）	1（60）	98.97	36.49
2	1	2（65）	2（10）	2（10）	2（90）	98.83	45.84
3	1	3（75）	3（20）	3（20）	3（120）	99.00	32.73
4	1	4（85）	4（30）	4（30）	4（150）	97.69	16.70
5	2（50）	1	2	3	4	98.98	42.10
6	2	2	1	4	3	99.33	37.10
7	2	3	4	1	2	98.77	30.28
8	2	4	3	2	1	99.04	34.33
9	3（55）	1	3	4	2	98.52	34.10
10	3	2	4	3	1	98.07	36.24
11	3	3	1	2	4	99.13	37.93
12	3	4	2	1	3	99.03	41.75
13	4（60）	1	4	2	3	98.35	44.66
14	4	2	3	1	4	98.68	51.86
15	4	3	2	4	1	98.74	42.92
16	4	4	1	3	2	99.11	33.02
纯度
k1	98.62	98.70	99.13	98.86	98.70
k2	99.03	98.73	98.90	98.84	98.81
k3	98.69	98.91	98.81	98.79	98.93	主次序：C>A>E>D>B
k4	98.72	98.72	98.22	98.57	98.62	优组合：A₂B₃C₁D₂E₃
R	0.41	0.21	0.91	0.29	0.31
收率
k1	32.94	39.34	36.14	40.10	37.50
k2	35.95	42.76	43.15	40.69	35.81
k3	37.51	35.97	38.26	36.02	39.06	主次序：B>C>A>D>E
k4	43.12	31.45	31.97	32.71	37.15	优组合：A₄B₂C₂D₂E₃
R	10.18	11.31	11.18	7.99	3.25