CN1062293C - Method for producing olefines by steam cracking heavy gas oil or raffinate oil from solvent extraction - Google Patents

Abstract

The present invention relates to a method for solvent extraction of heavy gas oil doffing aromatic hydrocarbon and gelatine and producing olefin by the raffinate oil and steam by cracking. The heavy gas oil contains aromatic hydrocarbon and gelatine and obstructs steam cracking and aromatic hydrocarbon preparation. The present invention adopting polarity solvent extraction of N-Methyl pyrrolidone has the advantages that the of the aromatic hydrocarbon of the raffinate oil is decreased below 16, gelatine is removed, steam cracking can increase the yield of ethene, the coking amount of each part of a cracking furnace is decreased, and the operating period is prolonged.

Description

The method of producing olefines by steam cracking heavy gas oil or raffinate oil from solvent extraction

The present invention relates to the solvent extraction heavy gas oil and take off aromatic hydrocarbons and colloid, the raffinate oil method of steam cracking system alkene of gained.Technical genus patent classification C10g 21/00, C10g 9/00.

Cracking petroleum hydrocarbon vapor system ethene and other alkene are the main raw material sources of petrochemical complex, and quarry usually cerebrol and solar oil are raw material.Because market demand constantly increases, supply falls short of demand for petroleum naphtha, solar oil, enlarges mink cell focus and utilize scope to become the task of top priority.

Prior art is to most selective hydrocracking of heavy-oil modified optimization and the extractive technological line of physics, but hydrogenation unit construction investment and production cost be all than higher, and therefore, mink cell focus extracting modified optimization comes into one's own.

U.S. TEXACO house journal 4333824; 4342646 and 4390418 have proposed the method for N-Methyl pyrrolidone (NMP) extracting lube stock, and it is motivated to be the base oil of making lubricating oil, but do not consider the requirement of its (raffinate) quality applied heat cracking system alkene of raffinating oil.

The United States Patent (USP) 3691061 of Gulf development company has proposed the essential oil and the catalytic cracking bonded technology of solar oil solvent extraction, its objective is volume increase gasoline, improves the octane value of gasoline, does not have the needs in conjunction with steam cracking system alkene.

The objective of the invention is to avoid the prior art weak point, provide a kind of heavy petroleum hydrocarbon to be applicable to the method for steam crack material by extracting modification manufacturing.

Purpose of the present invention can reach by following measure: after heavy gas oil takes off aromatic hydrocarbons and colloid with solvent extraction, the method of steam cracking system alkene, wherein the boiling range of heavy gas oil adopts the polar solvent extracting at 175-500 ℃, after removing aromatic hydrocarbons and colloid, raffinate oil as steam cracking feed.

Described heavy gas oil is air distillation third fractional oil, underpressure distillation one line oil, underpressure distillation two wires oil.

Purpose of the present invention can also reach by following measure: described polar solvent can be selected a kind of from N-alkyl pyrrolidone, furfural, alkyl morpholine, phenol, sulfoxide compound, dibasic alcohol and ethers thereof or its mixture.Best solvent is NMP.Spent solvent can reclaim.

Extraction temperature is decided on selecting solvent for use.Can fix on 60-90 ℃ when adopting NMP.The volume ratio of heavy gas oil and extraction solvent is 1: 1～1: 4.

The aromatic index (BMCI) that contains aromatic hydrocarbons by raffinating oil after the heavy gas oil extracting of the present invention is below 20, even reaches below 16.Raffinate oil and contain colloid and approach 0.0% (weight).

By the steam cracking under common cracking condition of raffinating oil of the present invention, cracking condition is as follows:

785 ℃ of heater outlet temperatures

Outlet of still pressure (definitely) 207Kpa

0.47 second residence time

96 hours proofs of water/oil ratio (m%) 0.75 operation can obviously improve ethene and triolefin yield, and the coking amount at each position of pyrolyzer also obviously reduces, and helps prolong operation cycle.

The drawing of accompanying drawing is described as follows:

The heavy gas oil charging of I-processing to be extracted;

II-extraction solvent;

III-raffinate oil;

IV-extraction oil;

V-raffinate and extract stripper top distilled wet solvent;

VI-dehydration;

VII-steam;

VIII-cracking product;

The 1-extraction tower;

2-raffinate stripping tower;

3-Extract evaporator tower;

The 4-extract stripper;

The 5-drying tower;

6-circulating solvent jar;

The 7-steam cracking furnace.

The present invention is described in further detail below in conjunction with example.

Embodiment 1 NMP extracting heavy gas oil removes aromatic hydrocarbons and the colloid preparation is raffinated oil

The normal pressure boiling range of the used heavy gas oil of the embodiment of the invention is 175-500 ℃.

Grand celebration normal pressure third fractional oil is taken from Yan Hua company refinery two distillation workshops

The grand celebration line oil that reduces pressure is taken from Yan Hua company refinery two distillation workshops

Grand celebration decompression two wires oil is taken from Yan Hua company refinery two distillation workshops

The heavy gas oil quality is as shown in table 1 before the extracting:

The composition data of heavy gas oil before table 1 extracting

	Grand celebration normal pressure third fractional oil	Grand celebration normal pressure one line oil	Grand celebration normal pressure two wires oil
				Molecular-weight average	280	285	340
Aromatic index	15.84	21.94	20.24
				Density (20 ℃) g/cm 3	0.8305	0.8450	0.8537
The ASTM-86 boiling range
				Initial boiling point (℃) do (℃)	177 395	277 440	335 490
Compositional analysis m%
				Paraffinic hydrocarbons naphthenic hydrocarbon aromatic hydrocarbons colloid	50.5 36.9 12.0 0.6	43.9 37.2 18.5 0.4	44.3 36.3 18.0 1.4

Solvent NMP Nanjing petrochemical corporation (complex) product (purity＞99%);

The multiple-downcomer sieve tray tower is adopted in extracting

5.2 meters of tower heights;

100 millimeters of tower internal diameters;

The extracting section is high 4.00 meters.

The extracting experimentation is as follows:

Heavy gas oil and NMP are heated to 65-85 ℃, earlier heavy gas oil are fed in the tower, feed NMP then, progressively two phase flow is transferred to process value until being full of full tower:

20 liters/hour of heavy gas oils

40 liters/hour of NMP running after 40 minutes the tower inner transmission matter reach balance substantially, the beginning sampling analysis, the extracting result is as shown in table 2:

Table 2 heavy gas oil NMP extracting result

The embodiment sequence number	1	2	3
				Stock oil	Grand celebration normal three is raffinated oil	Grand celebration subtracts raffinates oil	Grand celebration subtracts two and raffinates oil
Molecular-weight average	268	277	323
				Aromatic index (BMCI)	10.55	13.95	15.14
Density (20 ℃), g/cm 3	0.824	0.8316	0.8431
				The ASMT-86 boiling range
Initial boiling point (℃) do (℃)	299 387	253 437	252 462
				Compositional analysis m%
Paraffinic hydrocarbons naphthenic hydrocarbon aromatic hydrocarbons colloid	69.9 29.8 0.3 0.0	55.2 42.3 2.5 0.0	52.1 42.6 5.3 0.0
				Take off fragrant rate *m％	97	87	70

*ASTMD 2786-71，ASTMD 3239-76

Embodiment 2

Test conditions just replaces the grand celebration atmosphere 3rd side cut oil of example 1 with example 1 with the grand celebration first vacuum side stream.Extracting the results are shown in Table 2.

Embodiment 3

Test conditions just replaces the grand celebration atmosphere 3rd side cut oil of example 1 with example 1 with grand celebration second line of distillation oil.Extracting the results are shown in Table 2.

Embodiment 4,5,6

Grand celebration second line of distillation oil is done the test of differing temps and solvent composition ratio with furfural and NMP-furfural binary solvent, and gained is raffinated oil and formed as shown in table 3ly, illustrates that furfural or furfural-NMP binary solvent can use.

The extracting of table 3 grand celebration second line of distillation diesel oil binary solvent is comparative test result as a result

Embodiment	4	5	6	Second line of distillation stock oil
					Extraction temperature (℃)	60	73	81
Solvent composition (v/v)	Pure K K/N=3 K/N=1 *	Pure K K/N=3 K/N=2	Pure K K/N=3 K/N=2
					Solvent/oil (v/v)	1:1	1:1	1:1
The composition of raffinating oil									Form
				Total total cycloalkanes of the total alkane of aromatic hydrocarbons % colloid %	14.1 14.5 12.5 0.9 0.8 0.6 42.5 43.3 43.3 42.4 41.0 43.6	13.5 13.0 12.7 1.0 0.8 0.6 43.0 43.1 43.3 42.3 43.2 43.3	13.0 12.6 12.5 1.0 0.8 0.9 42.8 43.3 43.0 43.3 43.6 43.6	15.8 1.7 40.5 41.5

* annotate: K represents furfural; N representative-methyl-2-pyrrolidone.

By table 1,2 subtract a stock oil as can be seen, the BMCI value that subtracts two stock oils is high.Three kinds of oil are done all very high, the character of oil product is relatively poor, but the molecular-weight average of three kinds of oil and density and aromaticity content all descend to some extent behind solvent extraction, especially composition such as condensed-nuclei aromatics and colloid is partly or entirely extracted out, the character of oil product is optimized, it is apparent in view that the BMCI value descends, and three kinds of oil all reaches qualified cracking stock BMCI value less than 20 level.As the cracking stock alkene predecessor object height of will seeking survival, the performance that the green coke precursor is low is obviously improved.

Cracking EXPERIMENTAL EXAMPLE 9,11,13 and comparative example 7,8,10,12

The cracking experiment is carried out on simulation STR-II type testing apparatus, and device is made up of charging (convection zone), reaction (width of cloth section of penetrating), cooling (quench zone) three parts, and complete assembly is by a computer-controlled operation and monitoring operation.Cracking control condition is as follows:

Heater outlet temperature (℃) 785

Outlet of still pressure (Kpa, absolute) 207

The residence time (second) 0.40～0.47

Water/oil ratio (m%) 0.75

Treatment capacity (kilogram/hour) 1～3 breaking test condition and result are as shown in table 4.

The breaking test result raffinates oil before and after the extracting of table 4 heavy gas oil

	Comparative Examples 7	Comparative Examples 8	Embodiment 9	Comparative Examples 10	Embodiment 11	Comparative Examples 12	Embodiment 13
Cracking stock	Normal pressure solar oil (AGO)	Grand celebration normal pressure third fractional oil		The grand celebration line oil that reduces pressure		Grand celebration decompression two wires oil
								Before the extraction	Raffinate oil	Before the extraction	Raffinate oil	Before the extraction	Raffinate oil
		Separate processing condition
Heater outlet temperature (℃) outlet of still pressure (KPa)	785 207	785 207	785 207	785 207	785 207	785 207	785 207

The residence time (second) water-oil ratio (m%)	0.47 0.75	0.47 0.74	0.47 0.75	0.45 0.80	0.47 0.80	0.47 0.79	0.47 0.80
								The cracking result
The splitting gas yield, (m%) therein ethylene acrylonitrile-butadiene triolefin yield cracked oil yield, (m%) yield of total triphen, (m%) *	67.87 25.73 15.70 4.82 46.21 32.13 9.26	70.56 27.20 16.37 5.52 49.09 29.44 9.00	74.23 28.92 16.70 5.50 51.12 25.77 6.13	67.87 25.73 15.70 4.82 46.25 32.13 9.26	72.85 27.55 17.22 5.98 50.75 27.15 7.07	67.87 25.73 15.70 4 82 46.25 32.13 9.26	71.22 27.12 17.06 5.82 50.00 28.78 8.33
								Relative coking amount **
The convection zone width of cloth section of penetrating cooling section	100 100 100	98 121 103	88 81 79	125 189 108	104 150 82	147 328 131	117 193 97

* triphen is meant benzene,toluene,xylene; * is the high quality raw material cracking with the 90 years AGO in the Yanshan Mountain, and heater outlet temperature is 790 ℃, moves 96 hours coking amount and is 100% and make benchmark.By the embodiment of cracking experiment and Comparative Examples as can be seen: improved Tuo Fangtuo gelationus degree through extractive heavy gas oil raffinate, the splitting gas yield improves, particularly yield of ethene improves, the relative coking amount of raffinating oil is lower than or approaches high-quality AGO cracking material, thereby reaches the purpose that enlarges cracking stock.

Claims (6)

1. the heavy gas oil solvent takes off the method for steam cracking system alkene after aromatic hydrocarbons and the colloid, it is characterized in that the heavy gas oil boiling range is 175-500 ℃, raffinate oil as steam cracking feed after adopting polar solvent extracting aromatic hydrocarbons and colloid, wherein the aromatic index of raffinating oil behind the solvent extraction (BMCI) is less than 20, and gum level approaches 0.0% (weight).

2. method according to claim 1 is characterized in that described heavy gas oil is the air distillation third fractional oil, underpressure distillation one line oil and underpressure distillation two wires oil.

3. method according to claim 1 is characterized in that described polar solvent is to select a kind of or its mixture from N-alkyl pyrrolidone, furfural, alkyl morpholine, phenol, sulfoxide compound, dibasic alcohol and ethers thereof.

4. method according to claim 3 is characterized in that described polar solvent is a N-Methyl pyrrolidone.

5. method according to claim 1 is characterized in that extraction temperature is 60-90 ℃, and the volume ratio of heavy gas oil charging and extraction solvent is 1: 1～1: 4.

6. method according to claim 1 is characterized in that the described thermo-cracking under the condition of 785 ℃ of heater outlet temperatures, outlet of still pressure 207Kpa (definitely), 0.40～0.47 second residence time, water/oil ratio 0.75～0.80 (m%) of raffinating oil.