CN1042529C - Aromatization process for splitting SC-cut - Google Patents

Abstract

The present invention provides a technology for aromatizing petroleum hydrocarbons and a fixed bed reactor thereof. In the aromatizing technology of the present invention, cracked C5 fractions are used as raw materials and are heated and vaporized by a heating furnace, the heating temperature is from 350 to 500 DEG C, gas materials after the heating enter the fixed bed reactor for reaction, materials which are discharged from the reactor are condensed and cooled, liquid phase parts of the materials mainly comprise mixtures of benzene, toluene and xylene, the liquid yield of the reaction materials is from 63 to 67%(wt%), and aromatic hydrocarbon products of benzene, toluene, xylene, etc., are respectively obtained through the separation of a rectification system. Shape selective catalysts are filled in the fixed bed reactor, the catalysts use ZSM-5 type molecular sieves as carriers and comprise active components of Al2O3, SiO2, Zn, Na, Ge, etc. When the technology of the present invention is used, the cracked C5 fractions can be directly used as fuels, and can be comprehensively utilized, the production cost is greatly lowered, the use added value of the cracked C5 fractions is enhanced, unnecessary waste is reduced, and therefore, the technology of the present invention has good popularization prospects.

Description

Aromatization process for splitting SC-cut and reactor thereof

The present invention relates to the cracking hydrocarbon oil of petroleum hydrocarbon, be meant by product cracking C especially cracking hydrocarbon oil ₅(being carbon five, down together) cut carries out aromizing, and adopting type ZSM 5 molecular sieve is that carrier is with Al ₂O ₃, SiO ₂, Zn, Na, Ge etc. are the type of the selecting catalyzer of active principle, carry out reaction such as deoxidation, aromatization and obtain the technology and the conversion unit thereof of aromatic hydrocarbons.

Existing to cracking hydrocarbon oil by product cracking C ₅The utilization of cut, the domestic overwhelming majority use that acts as a fuel is not abroad seen about cracking C as yet yet ₅The report of aromizing industrialness production application.Though existing lower carbon number hydrocarbons (C ₂～C ₄) report of technology of aromatization technology, but it can only use Sweet natural gas and refinery gas to be raw material, can't solve to use cracking C ₅Cut is the relevant Technology of raw material production aromatic hydrocarbons.Thereby both at home and abroad to this refining of petroleum by product cracking C ₅The comprehensive utilization of cut does not all have the fixed production model as yet.

It is a kind of with cracking hydrocarbon oil by product cracking C that purpose of the present invention just is to provide ₅Cut is that raw material carries out aromizing and is suitable for the Technology and the conversion unit thereof of suitability for industrialized production, and this production technique is with cheap cracking C ₅Cut is aromatic hydrocarbon products such as raw material production benzene,toluene,xylene, goes back by-product ethene, propylene and liquefied petroleum gas (LPG) simultaneously, makes C ₅Cut is able to sufficient comprehensive utilization.

Production technique of the present invention is with cracking C ₅Cut is a raw material, and through vaporizer, process furnace heating vaporization, the Heating temperature scope is 350～500 ℃ to raw material earlier; Heating back gas material enters the fixed-bed reactor reaction, is filled with shape-selective catalyst in the reactor, and catalyzer is carrier with the type ZSM 5 molecular sieve, with Al ₂O ₃, SiO ₂, Zn, Na, Ge etc. be active principle; Reaction pressure 0.05～0.3MPa, air speed 0.3～0.8h ^-1The reaction mass that goes out reactor is after the condensation cooling, gas phase part is by recovery system separating and reclaiming ethylene, propylene and the liquefied petroleum gas (LPG) of sloughing heavy constituent, liquid phase part mainly is the benzene,toluene,xylene mixture, obtains aromatic hydrocarbon products such as benzene,toluene,xylene after separating through distillation system respectively; For cracking C 5 fraction raw material, the gas yield of reaction mass is 30-33% (wt%), and liquid yield is 63-67% (wt%).The raffinate of rectifying discharging is mainly the C9 component, offers Subscriber Unit as the C9 solvent oil.

Cracking C ₅The technological process of aromizing, some principal reactions of generation are as follows: (not comprising total overall reaction)

(1) long chain alkane generation scission reaction in the raw material:

(2) alkane in the raw material carries out dehydrogenation reaction under catalyst action:

(3) oligomerisation takes place in alkene under catalyst action:

(4) oligopolymer dehydrocyclization under catalyst acid central role becomes aromatic hydrocarbons:

Cracking C ₅The key of technology of aromatization is to have adopted fixed-bed reactor and selected with Al ₂O ₃, SiO ₂, Zn, Na, Ge etc. be the modified ZSM-5 type molecular sieve catalyst of active principle.Fixed-bed reactor are cylinder mode, and gaseous phase materials enters reactor by top and leaves from its underpart.The entry site of gas phase is provided with the gas inlet sparger, and outlet at bottom is provided with the cover cap and takes out of with gas to prevent catalyzer.The both sides, top of reactor are provided with the catalyzer loading port, and two bottom sides has catalyzer to unload outlet.The catalyzer close packing is in reactor, for the heat that reaction is produced is in time taken out of, be provided with heat collector in the built-up type in the reactor, reached the purpose that reclaims heat energy simultaneously by making steam superheating can in time shift out reaction heat, catalyst regeneration operates in the fixed-bed reactor and carries out, realize internal regeneration, significantly reduced the wearing and tearing of catalyzer.

Of the present invention with cracking C ₅Cut is the technology of raw material production aromatic hydrocarbons, also pyrolysis gasoline, condensation wet goods can be replenished as raw material, and its raw material scope of application is wider, is not limited to cracking C ₅Cut.

Advantage of the present invention just is to provide a kind of cheap cracking C that uses ₅Cut is the technology and the reactor thereof of raw material production aromatic hydrocarbons, makes cracking C ₅The use of cut also can be fully utilized except that directly acting as a fuel, and greatly reduces production cost, has improved it and has used added value, has reduced unnecessary waste.And this technology do not have residual liquid discharge, and production process can not work the mischief to environment substantially.Owing to adopted reclaiming process in fixed-bed reactor and the catalyst body, make simple to operately, catalyst abrasion is little, and the steam superheating mode by heat collector in the reactor not only can in time shift out reaction heat but also has reclaimed heat energy.Therefore adopt Technology of the present invention to produce aromatic hydrocarbons and have promotion prospect preferably.

Below in conjunction with accompanying drawing technology of the present invention and reactor thereof are further described.

Fig. 1 is a process flow diagram of the present invention;

Fig. 2 is a fixed-bed reactor structural representation of the present invention.

With reference to Fig. 1, technological process of the present invention is divided into aromatization and separates two parts with rectifying, equipment comprises regeneration gas gas holder [1], regeneration gas heat exchanger [2], regeneration gas cooler [3], regeneration gas separator [4], regeneration gas compressor [5], C5 storage tank [7], vaporizer [9], heating furnace [10], fixed bed reactors [12], drum [13], waste heat boiler [14], reactor heat exchanger [15], reaction gas cooler [16], exhaust gas cooler [17], gas-liquid separator [18], reaction gas gas holder [19], reactant liquor storage tank [21], feed exchanger [22], tower reboiler [23], non-aromatic tower [24], overhead condensation cooler [25], backflow cylinder [26], benzene rectifying column [27], toluene rectifying column [29], xylene distillation tower [31] etc. Such as figure, C₅Feedstock enters C through storage tank import [6]₅Storage tank [7], steam [8] is used for the C in the vaporizer [9]₅The vaporization of cut, soft water [11] are removed drum [13] after entering heating furnace [10], and the reacting gas that goes out fixed bed reactors [12] is through reaction gas gas holder [19] the body separator [20] that degass. Liquid phase material obtains respectively benzaldehyde product [28], toluene product [30], dimethylbenzene product [32] through benzene rectifying column [27], toluene rectifying column [29], xylene distillation tower [31], pumped vacuum systems [33] is connected 31 with toluene rectifying column [29] with the xylene distillation tower respectively] be connected, discharge C at the bottom of xylene distillation tower [31] tower₉Cut and tar [34].

Because the catalyst single pass life is about 24-50 hour, general many group gasifiers, heating furnace, fixed bed reactors parallel-connection flow, the needs that hocket to adapt to fixed bed reactors [12] aromatization and catalyst regeneration of adopting of the aromatization part of technique of the present invention. When carrying out aromatization, by feed pump with C₅Cut is from C₅Storage tank [7] is delivered to vaporizer [9], material is through vaporizing and being raised to about 160 ℃, enter again heating furnace [10] and be warming up to 350-500 ℃, heating furnace is made fuel with methane gas, gas material after the heating enters fixed bed reactors [12], under the effect of modified molecular screen shape-selective catalyst series reaction occurs. The optimal reaction temperature of fixed bed reactors [12] control is 350-400 ℃, and optimum response pressure is 0.05-0.3MPa, air speed 0.3-0.8h^-1 The reacting gas temperature that goes out fixed bed reactors [12] is 450-550 ℃, and it is cooled to about 350 ℃ through waste heat boiler [14] and further is cooled to about 250 ℃ by reaction gas heat exchanger [15], then enters reaction gas cooler [16]. Behind condensing cooling, its condensate liquid is the mixture of benzene,toluene,xylene etc., by being pumped into reactant liquor storage tank [21] as the rectifying charging; Its tail gas is the mixture of ethene, propylene, liquefied petroleum gas etc., is sent to reaction gas gas holder [19] after exhaust gas cooler [17] cooling. When carrying out catalyst regeneration, the aromatization process stops, oxygen content in the regeneration gas gas holder [1] is delivered to regeneration gas heat exchanger [2] heat exchange less than 2% nitrogen through regeneration gas compressor [5] supercharging be warming up to 250 ℃, system's controlled pressure is that normal pressure is to 0.5MPa, then be warming up to through heating furnace [10] and enter fixed bed reactors [12] about 450-550 ℃ again, carbon deposit makes catalyst regeneration on the burning-off catalyst coating. The gas that burns that goes out fixed bed reactors [12] is cooled to 350 ℃ after regeneration gas heat exchanger [2] heat exchange, heated simultaneously the regeneration gas that enters fixed bed reactors [12], burn gas after regeneration gas cooler [3] further is cooled to less than 50 ℃, begin again a new round by regeneration gas compressor [5] behind the additional part air and burn circulation. The recovery time of catalyst and aromatization time are equal to substantially. Through the liquid phase material mixtures such as benzene,toluene,xylene that aromatisation obtains, its " triphen " content accounts for more than 90% (wt%), and the distillation and separation method by routine obtains respectively the aromatic hydrocarbon products such as benzene,toluene,xylene, and the raffinate of discharge is with C₉Cut is main, as C₉Solvent naphtha offers Subscriber Unit and uses. Adopt the basic three-waste free discharge of technology of aromatization of the present invention, heating fume emission after measured CO content was less than or equal to for 0.2% (meeting discharge standard); Heavy metal free pollutes in the discarded catalyst, concentrates after calcining and buries processing.

With reference to Fig. 2, fixed bed reactors are cylinder mode, ratio of height to diameter: 1.9: be mainly the formations such as cylindrical shell, material inlet, material outlet, catalyst inlet [1], [2], catalyst outlet [3], [4], gas inlet distributor [5], gas vent cover cap [6], interior heat collector [7]. Top gas inlet distributor [5] is frustum of a cone multilayer conical distribution structure, by 4 layers of descending cast gas access passage Uniform Dispersion entrance gas phase, has effectively guaranteed the even distribution of gas. Bottom gas vent cover cap [6] is cylindrical structure, and its diameter is D9600, and its top is by cover closure, and wall has bar hole, and gas vent cover cap [6] major function is to prevent taking out of of catalyst. Interior heat collector [7] adopts the seamless steel pipe of Φ 57 * 3.5, is installed in the cylindrical shell inner ring distance Φ 600 such as figure minute three circles; Centre circle spacing Φ 1200; Outer ring spacing Φ 1700. Steam enters coil pipe by the reactor shell lower end, and upper recircling to the coil pipe top and descending exports from the lower end opposite side at last. The interior heat collector form also can adopt shell and tube and other forms. Can in time shift out again recyclable heat energy of reaction heat by interior heat collector [7].

Below be embodiments of the invention.

Example 1, cracking C ₅Production contrast under the differential responses temperature

Year is handled cracking C ₅10,000 tons of cuts adopt fixed-bed reactor nominal diameter Dg2200mm, volume 12M ³Catalyzer is with Al ₂O ₃, SiO ₂, Zn, Na, Ge etc. are carrier for active principle with ZMC-5 type molecular sieve, useful volume 8.5M ³The operation air speed is 0.3-0.8h ^-1

1, cracking C ₅The raw material composition is listed in table 1;

2, the product composition under the differential responses temperature is listed in table 2.

Table 1 cracking C ₅The composition of raw material

Component	Cracking C 5Cut	Benzene	Toluene	Ethylbenzene	P-Xylol	M-xylene	O-Xylol	C 5Aromatic hydrocarbons
									Content (wt%)	89.673	9.069	0.415	-	0.532	-	-	0.321

Product under the table 2 differential responses temperature is formed (wt%)

Temperature of reaction ℃	Gas composition						Aromatic hydrocarbons is formed							Total aromatic hydrocarbons
															C 1°	C 2 -	C 2°	C 3 -	C 3°	C 4	Benzene	Toluene	Ethylbenzene	P-Xylol	M-xylene	O-Xylol	C9 aromatic
	560	4.36	5.36	6.23	2.90	8.68	4.28	15.6	30.81	0.9	3.48	8.27	3.74															1.56	64.36
520														3.50	6.32	6.33	4.84	7.29	3.71	17.33	31.08	1.1	3.26	7.81	3.69	2.04	66.31
	480	2.33	5.85	4.91	5.06	6.14	4.0	19.84	27.76	2.44	3.71	7.14	3.29															3.73	67.91

Example 2: use different material to realize the contrast that aromizing is produced

Reaction control temperature 350-500 ℃, use cracking C respectively ₅, cracking C ₅Mixing light oil and light oil is raw material, and other conditions are with example 1.

1, different raw material compositions are listed in table 3;

2, the product of different material composition is listed in table 4.

The different raw material of table 3 is formed (wt%)

Name of material	Form
									Non-aromatics	Benzene	Toluene	Ethylbenzene	P-Xylol	M-xylene	O-Xylol	C9 aromatic
	Cracking C 5	99.109	-	-	-	-	-	-									0.326
Cracking C 5Mix light oil									47.638	32.028	15.690	0.274	-	1.477	2.89	-
	Light oil	18.254	46.384	24.817	0.576	0.896	1.941	0.835									6.35

The product of table 4 different material is formed (wt%)

Name of material	Gas composition						Aromatic hydrocarbons is formed							Total aromatic hydrocarbons
															C 1°	C 2 -	C 2°	C 3 -	C 3°	C 4	Benzene	Toluene	Ethylbenzene	P-Xylol	M-xylene	O-Xylol	C9 aromatic
	Cracking C 5	3.96	3.26	6.09	2.74	11.64	4.22	14.07	31.85	1.39	3.95	8.74	3.91															0.23	64.14
Cracking C 5Mix light oil														2.02	2.63	5.15	1.87	5.81	1.37	28.85	31.62	2.66	2.95	5.91	2.77	1.31	76.07
	Light oil	1.07	0.76	2.07	0.48	2.94	0.34	49.59	29.54	2.69	1.44	3.33	1.79															0.59	88.97

Example 3 is that raw material uses different catalyzer to carry out the contrast of aromizing with light oil

Reaction control temperature is 350-450 ℃, and other conditions are with example 1.

1, the composition of light oil raw material is listed in table 5; 2, the product of different catalyzer composition is listed in table 6.

The composition (wt%) of table 5 light oil raw material

Component	Non-aromatics	Benzene	Toluene	Ethylbenzene	P-Xylol	M-xylene	O-Xylol	C9 aromatic
									Content	16.847	46.901	24.448	0.514	0.977	2.204	1.048	4.86

The product of the catalyzer that table 6 is different is formed (wt%)

Catalyzer research institute title	Gas composition						Aromatic hydrocarbons is formed							Total aromatic hydrocarbons
															C 1°	C 2 -	C 2°	C 3 -	C 3°	C 4	Benzene	Toluene	Ethylbenzene	P-Xylol	M-xylene	O-Xylol	C9 aromatic
	Nankai University	0.66	0.91	1.02	0.73	1.91	1.02	51.56	29.89	3.04	1.57	2.91	1.37															1.64	91.98
Kingsoft, Shanghai general petrochemicals factory														0.98	3.24	1.19	2.68	2.01	1.74	45.53	26.99	3.35	1.67	3.87	2.49	1.43	85.33
	Huadong Chemical College	0.47	3.16	0.26	3.93	0.95	1.99	48.05	27.71	2.18	1.12	2.40	2.12															2.81	86.39

Claims (4)

1, a kind of petroleum hydrocarbon technology of aromatization is characterized in that:

A. with cracking C ₅Cut is a raw material, through process furnace heating vaporization, Heating temperature is 350-550 ℃, heating back gas material enters the fixed-bed reactor reaction, the material liquid phase part after the condensation cooling that goes out reactor mainly is the benzene,toluene,xylene mixture, the liquid yield of reaction mass is 63-67% (wt%), obtains the benzene,toluene,xylene aromatic hydrocarbon product respectively after distillation system separates;

B. load shape-selective catalyst in the fixed-bed reactor, catalyzer is a carrier with the type ZSM 5 molecular sieve, with Al ₂O ₃, SiO ₂, Zn, Na, Ge be active principle.

2, according to claim 1 with cracking C ₅Cut is the petroleum hydrocarbon technology of aromatization of raw material, it is characterized in that aromatization partly adopts the flow process of many group gasifiers, process furnace, fixed-bed reactor parallel connection, and aromatization and catalyst regeneration hocket; With oxygen level less than the compressed machine supercharging of 2% nitrogen, Controlling System pressure is that normal pressure is to 0.5MPa, be warming up to about 450-550 ℃ through process furnace and enter fixed-bed reactor, burning-off catalyst coating carbon deposit makes catalyst regeneration, and regenerative operation time and aromatization time are equal to substantially.

3, according to claim 1 with cracking C ₅Cut is the petroleum hydrocarbon technology of aromatization of raw material, and the reaction control temperature that it is characterized in that fixed-bed reactor is 350-400 ℃; Reaction pressure is 0.05-0.3MPa, air speed 0.3-0.8h ^-1

4, a kind of cracking C as claimed in claim 1 ₅Cut is the employed fixed-bed reactor of petroleum hydrocarbon technology of aromatization of raw material, it is characterized in that its gas phase entry site is provided with gas inlet sparger [5], and outlet at bottom is provided with pneumatic outlet cover cap [6], and is provided with interior heat collector [7] in reactor.