US20030111388A1

US20030111388A1 - Process for catalytic upgrading light petroleum hydrocarbons accompanied by low temperature regenerating the catalyst

Info

Publication number: US20030111388A1
Application number: US10/156,916
Authority: US
Inventors: Ruichi Zhang; Jianguo Ma; Zhili Qin; Jiushun Zhang; Zhijian Da
Original assignee: Sinopec Research Institute of Petroleum Processing
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2001-05-30
Filing date: 2002-05-29
Publication date: 2003-06-19
Also published as: RU2276182C2; RU2002114064A; CN1179022C; CN1388217A

Abstract

This invention relates to a process for catalytically upgrading light petroleum hydrocarbons accompanied by low temperature regenerating the catalyst, which comprises injecting the light petroleum hydrocarbons into a catalytic cracking reactor, contacting the light petroleum hydrocarbons with a regenerated catalyst and carrying out the reaction, separating the reaction products regenerating the stripped catalyst for 10 to 50 minutes under the regeneration conditions of a temperature of 400 to 600° C. and a pressure of 0.1 to 0.6Mpa; recycling the regenerated catalyst into the reactor. The process of the present invention can reduce the olefin content of gasoline, increase the cetane number of diesel oils, and decrease the contents of sulfur and nitrogen to some extent.

Description

FIELD OF THE INVENTION

The present invention relates to a catalytic conversion process of petroleum hydrocarbons in the absence of hydrogen, more particularly, a catalytic upgrading process of light petroleum hydrocarbons accompanied by low temperature regenerating the catalyst.

BACKGROUND OF THE INVENTION

Nations all round the world have established the corresponding environmental protection laws for strictly controlling a variety of exhaust emissions and pollutants discharged in order to create clean and beautiful living surroundings for the human beings. Tail gas from motor vehicles is one of the important pollution sources which cause inestimable deterioration effects to the environment. The key to control the tail-gas pollution of motor vehicles is to improve the qualities of fuel oils Therefore, many nations have raised more and more strict requirements for the quality of gasoline and/or diesel oils, especially the limitation for the contents of certain components in gasoline and diesel oils

In the prior art, there are a lot of processes for improving gasoline quality. For example, U.S. Pat. Nos. 5,043,522 and 5,846,403 disclose a process for reprocessing gasoline by feeding the catalytic gasoline to the upstream of feeding nozzle of feedstock oil to carry out catalytic conversion of the gasoline by using a regenerated catalyst with a high temperature and a high activity. In said process, the yield of light olefins such as propylene, butylene and the like can be increased while the gasoline octane number is raised.

CN 1160746A also discloses a catalytic conversion process for increasing gasoline octane number. In this process, a gasoline of poor quality, such as straight-run gasoline, coking gasoline and the like, is fed to the bottom of a riser reactor, and preferably contacts with the regenerated catalyst, and reacts under the conditions of a reaction temperature of 600 to 730° C., a weight hourly space velocity of 1 to 180hr ⁻¹and a catalyst-oil ratio of 6 to 180. This process can increase the octane number of the poor quality gasoline, and reduce the olefin content in the gasoline to some extent.

In CN 1069054A and U.S. Pat. No. 3,784,463, both reactions are conducted by using a catalytic cracking unit equipped with double riser reactors. A poor quality gasoline including a catalytic cracking crude gasoline was fed to the gasoline riser reactor and catalytically upgraded therein under the reaction conditions of high temperature and large catalyst-oil ratio for improving the yield of liquefied gas and the octane number of gasoline. But the conventional catalytic cracking feedstock was reacted in the feedstock oil riser reactor. This process is complicated in processing and very difficult in operation.

U.S. Pat. No. 5,372,704 discloses a catalytic upgrading process for gasoline by using a spent catalyst. In this process, a gasoline cracking rector is added in the conventional catalytic cracking processing flow, and the stripped spent catalyst in contacted with a gasoline fraction that needs to be upgraded in the gasoline cracking reactor, and reacted with each other under the conventional catalytic cracking reaction condition. The reacted catalyst was recycled to a riser reactor and mixed with the regenerated catalyst to carry out the conventional catalytic cracking reaction. The process can increase gasoline octane number and provide some effect to reduce the olefin content in gasoline.

In the prior art, improving quality of diesel oil is carried out mainly by hydroprocessing catalytically upgrading of products under a pressure in the presence of hydrogen to achieve the object of desulfurization, denitrogenation, olefin saturation and/or aromatics saturation.

From the above-mentioned contents it is observed that a majority of means for solving the quality problems of gasoline and diesel oil in the prior art are complicated and also relate to multi-step reaction procedures. At present, there is no easy and effective way that is capable of solving the quality problems of gasoline and diesel oil.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an effective process for improving the quality of gasoline and/or diesel oil based on the prior art in order to solve the problems of the quality of fuel oils in oil-refining enterprises.

The process provided in the present invention comprises: a) introducing the light petroleum hydrocarbons and the regenerated catalyst into a reactor to form a mixture of the feedstock and the catalyst; b) catalytically converting the light petroleum hydrocarbon under the conditions of a temperature of 200 to 450° C., a pressure of 0.1-0.5 Mpa, a catalyst-oil ratio of 2 to 15 and a reaction time of 1 to 20 seconds to form a effluent including gasoline, diesel oil and liquefied gas, and the spent catalyst; c) disengaging the spent catalyst from the effluent; d) stripping the spent catalyst; e) regenerating the stripped spent catalyst for 10 to 50 minutes under a temperature of 400 to 600° C. and a pressure of 0.1 0.6 Mpa; f) feeding the regenerated catalyst back to the reactor for reuse through circulation. The light petroleum hydrocarbon is typically the fraction having a final boiling point of less than 400° C.

DETAILED DESCRIPTION OF THE INVENTION

The process provided in the present invention is suitable for not only in any conventional type of catalytic cracking reactors, such as fluidized beds, risers or down-flow reactors, but also any modified catalytic cracking reactors based on the aforementioned reactors.

The essential reaction conditions of the process provided in the present invention are as follows a reaction temperature range from 200 to 450° C., preferably 200 to 400° C. a catalyst-oil ratio of 2 to 15 preferably 3 to 10, a reaction time of 1 to 20 second, preferably 2 to 10 second and a reaction pressure (absolute) range from 0.1 to 0.5 Mpa. Preferably 0.15 to 0.4Mpa.

The quantity of atomization steam injected is the same as that in the conventional catalytic cracking process. The weight ratio of atomization steam to light petroleum hydrocarbon is 0.01 to 0.2, preferably 0.02 to 0.05.

The stripper suitable for the present invention may be any type of catalytic cracking strippers. Since the stripping temperature of catalyst is relatively low according to the present invention, it should be noted to increase the stripping efficiently. During the procedure of stripper design and operation of the apparatus, the parameters such as stripping time, stripping steam rate, mass flow rate of catalyst in stripper, stripping temperature and the like should be optimized as far as possible. Furthermore, any high efficient stripper or multistage stripper and the like may be selected. Operating conditions of the stripper may be as follows: a stripping temperature of 200 to 450° C., preferably 300 to 400° C., a weight ratio of stripping steam to light petroleum hydrocarbon of 0.005 to 0.05, preferably 0.01 to 0.05, a mass flow rate of 100 to 300 ton/m ².hr of catalyst in the stripper, preferably 100 to 200 ton/m².hr, and a stripping time of 0.5 to 10 minutes, preferably 1 to 5 minutes. When a lower reaction temperature, e.g. 200° C., is used for the catalytic upgrading of light petroleum hydrocarbons, overhead steam with a high temperature should be used for stripping so as to increase stripping temperature and improving stripping efficiency; or a part of regenerated catalyst with high temperature may be introduced to the stripper and mixed with the lower temperature spent catalyst in order to increase the stripping temperature therein.

The regenerating conditions used in the present invention are much moderate than those in the conventional catalytic cracking process. According to the invention, the regeneration temperature in dense phase is 400 to 600° C., preferably 450 to 550° C.; the regeneration time is 10 to 60 minutes, preferably 10 to 30 minutes, and the regeneration pressure is 0.1 to 0.6Mpa, preferably 0.15 to 0.45Mpa. For ensuring aforementioned conditions in the regenerator, the content of excess oxygen in regeneration flue gas should be less than 5% by volume, preferably less than 1% by volume. The carbon content of the regenerated catalyst may be controlled at less than 0.7% by weight, preferably less than 0.5% by weight. Furthermore, in order to operate the process of the present invention more flexibly, a cooler for cooling the catalyst may be fitted at downstream of the regenerator to cool a part of or all parts of the regenerated catalyst which is then recycled into the reactor. According to the present invention, a nozzle for combustion oil can also be mounted in the regenerator so that the heat balance in the system can be adjusted in a flexible way.

The catalyst used in the present invention may be any solid acid catalyst suitable for catalytic cranking process, preferably a catalyst containing high-silicone zeolite with pentasil (pentatomic ring) structure, for example, the catalyst containing ZSM-5 zeolite or ZRP zeolite. The high silicone zeolite may be added during the preparation of the catalyst, or may be prepared alone as an additive containing high silicone zeolite with pentasil structure and added to the catalytic cracking unit. The content of the high silicone zeolite in the catalyst used in the present invention is preferably higher than 2% by weight, more desirably higher than 5% by weight. The catalyst used in the present invention may also contain a Y-type zeolite which is used commonly in the field of catalytic cracking field and a modified zeolite obtained by ion-exchanging or various physico-chemical treatments, for example, HY, REY, REHY, USY, REUSY and the like. The catalyst matrices used in the present invention can be selected from matrices commonly used in catalytic cracking catalysts, such as SiO ₂, Al₂O₃, Al₂O₃-clay, SiO₂-clay and the like. In the process of the present invention, one or more additives, such as octane number improver, combustion improver, desulfurizer and the like may also be used.

The process provided in the present is suitable for employing in different light petroleum hydrocarbons which need to be upgraded or modified, their ASTM distillation ranges may be within the range from an initial boiling point to 400° C., preferably form an initial boiling point to 360° C. The light petroleum hydrocarbon that needs to be upgraded, may either be a gasoline and/or diesel oil manufactured by primary processing processes, such as straight-run gasoline, straight-run diesel oil, or a gasoline and/or diesel oil manufactured by secondary processing processes, such as coking gasoline, coking diesel oil, cracking gasoline, cracking light cycle oil, hydrogenated gasoline and the like, or the mixture of the above-mentioned two or more oils.

In comparison with the prior art, the present invention has the following advantages:

The process provided in the present invention depends on a matured catalytic cracking technique by using the continuous reacting and regenerating processes to achieve the catalytic upgrading of light petroleum hydrocarbons. Therefore, the process is simple and easy to be carried out, which needs a little bit change of the conventional catalytic cracking unit.

With a wide range of feedstocks suitable to be used, the process provided in the present invention can be used either for improving quality of gasoline fractions such as straight-run gasoline, coking gasoline, cracking gasoline and the like, or for upgrading diesel oil fractions such as cracking light cycle oil, coking diesel oil and the like, or for treating the mixed oils of gasoline and diesel oil.

Treating different light petroleum hydrocarbons by using the process provided in the present invention may result in different upgraded effects. For example, after a straight-run gasoline is treated with the process of the present invention, its octane number can be increased and its impurity contents of sulfur, nitrogen and the like can be reduced; after a cracking gasoline is treated with the process of the present invention, its olefin content and impurity content of sulfur, nitrogen and the like can be decreased; after a diesel oil fraction, such as cracking light cycle oil, coking diesel oil and the like, is treated with the process of the invention, the content of sulfur and nitrogen therein can be decreased and the freezing point thereof can be lowered.

The process provided in the present invention has good selectively to the products and can give more than 90% by weight of the yield of high valuable products.

According to the process of the present invention, the regeneration of catalyst can be conducted at a lower regeneration temperature, leading to the reduction of the hydrothermal deactivation of the catalyst, and the service life of catalyst can thus be elongated and the consumption of the catalyst running in the unit can also be decreased. Furthermore, owing to a lower regeneration temperature used in the process of the present invention, the requirement for the quality of the material of the regenerator will be lowered during construction of the apparatus, and accordingly the investment in the apparatus construction will be cut down.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic flow diagram of the process provided in the present invention.[0024]
The catalytic cracking unit provided with a riser reactor is exemplified as follows to further illustrate the process of the present invention in combination with the accompanying drawings, but not thus to restrict the scope of the present invention. [0025]
As shown in FIG. 1, a preheated light petroleum hydrocarbon feedstock is fed to a [0026] riser reactor 2 via a pipeline 1, contacted with a regenerated catalyst from a pipeline 15, and carried out the reaction in the presence of water steam. The reaction oil gas, steam and the deactivated catalyst are subjected to gas/solid phase separation in a disengaging means 7. The reaction products are transferred to a follow-up separation system via an oil gas pipeline 8 to be further separated into different products. The spent catalyst which accumulates certain quantity of coke falls into a stripper 3. The steam is introduced into the stripper via a pipeline 4, after then the spent catalyst is transferred to a regenerator 13 via a pipeline 5 to burn coke deposited on the catalyst. The oxygen-containing gas is introduced to the regenerator 13 via a pipeline 14; the flue gas produced by the regeneration enters to a follow-up energy recovery system via a pipeline 12. The regenerated catalyst, which has the carbon content in conformity with the requirement of the present invention, is fed back to the reactor 2 for recycling use.
The following Examples further illustrate the present invention, but are not intended to restrict the scope of present invention. [0027]
Example 1 [0028]
This example illustrates that the carbon content of the regenerated catalyst can satisfy the requirement of the process of the present invention after the spent catalyst is regenerated under the regeneration conditions according to the present invention. [0029]
In order to observe the influence of regeneration temperature and regeneration time on the catalyst regeneration effects, the test was carried out in a muffle furnace by using a catalyst to be regenerated having the carbon content of 1.22% by weight . The text steps were described briefly as follows: more than 10 g of the catalyst to be regenerated in a crucible was put in the muffle furnace at the stabilized temperature of 400° C. for 50 minutes, then removed out, and naturally cooled under nitrogen protection, when the temperature of the catalyst was close to room temperature, then the carbon content and micro-activity were sampled and analyzed. The other regeneration conditions listed in Table 1 below were continuously tested according to aforementioned test steps. [0030]

the main operation conditions and the test results were shown in Table 1. It can be seen from Table 1 that the carbon content of the catalyst is notably decreased, and the catalytic activity can be recovered after the catalyst was regenerated under said regeneration conditions of the present invention.-

TABLE 1


						spent
Number	1	2	3	4	5	catalyst

Regeneration	400	450	500	550	600	/
temperature,
° C.
Regeneration	50	40	30	20	10	/
time, min.
Carbon content	0.77	0.67	0.34	0.25	0.12	1.22
of catalyst,
wt %
Micro-Activity,	46	48	54	57	61	38
MA

Example 2 [0032]
This example illustrates that the quality of the cracking gasoline is improved substantially and can be used for gasoline as a relatively desirable blending component after the gasoline is treated by the process provided in the present invention. [0033]
The catalyst used in the test was industrially manufactured by the Catalyst Factory of Qi-Lu Petrochemical Corporation with the brand CIP-3, and the main physical-chemical properties were shown in Table 2. the catalyst contained ZRP zeolite and y zeolite. The properties of the catalytic cracking gasoline feedstock used in the test are shown in Table 3. The present example was carried out in a pilot unit which includes the four parts of feeding, reacting, regenerating and fractioning, and had 0.036 ton/day of treatment capacity. [0034]
The main test steps were as follows: in a pilot FCC unit, the cracking gasoline aforementioned was preheated, then atomized by steam and injected into the riser reactor to contact with the regenerated catalyst in said reactor. The reaction was carried out under the conditions as shown in Table 3. The reacted product was led to a follow-up separator unit from the top of the reactor. The reacted catalyst was stripped with steam therein, then introduced into a regenerator for the regeneration by burning coke. The regenerated catalyst was fed back to the reactor for recycling use. Various reaction products were collected and analyzed for their physicochemical properties. [0035]
The main reaction conditions and the test results were shown in Table 3. From Table 3, it can be observed that the yield of the gasoline product was 90.73% by weight; in comparison with the cracking gasoline as a feedstock, the olefin content of the gasoline was decreased by about 13 percent, and the sulfur and nitrogen contents were also decreased to some extent. [0036]
Example 3 [0037]
this example illustrates that the quality of the coking diesel oil is improved substantially and the coking diesel oil can thus be used as a blending component of diesel oils after the coking diesel oil was treated by the process provided in the present invention. [0038]
The test apparatus, procedure and catalyst used were all the same as those in Example 2. In this example, coking diesel oil of pipeline crude oil (of China) was Used as the feedstock, and the properties thereof were shown in Table 4. [0039]
The main reaction conditions and the test results were shown in Table 4. From Table 4, it can be observed that the yield of liquefied gas + gasoline + diesel oil was 96.62% by weight, in which the yield of the diesel oil product was 81.62% by weight; after the coking diesel oil was treated under the reaction as mentioned above: in comparison with the coking diesel oil used as feedstock, the content of sulfur and nitrogen in the reacted diesel oil product was reduced to a great extent, the percentage of desulfurization was about 88%, the nitrogen percent was about 97%, the actual gum was decreased from 189mg/100ml to 92mg/100ml, and the freezing point was decreased from −3°C. to −13° C. [0040]
Example 4 [0041]
This example illustrates that the qualities of the gasoline and diesel oil product are improved substantially, and thus the light petroleum hydrocarbon can be used as a blending component of gasoline or diesel oil respectively after the light petroleum hydrocarbon is treated by the process provided in the present invention. [0042]
In this example, a mixed oil of catalytic cracking gasoline and hydrogenation diesel oil was used as a feedstock. The feedstock contained 80% by weight of the cracking gasoline and 20% by weight the hydrogenation diesel oil and the properties of the feedstocks were shown in Table 6. The catalyst used was RMG catalyst (brand) industrially manufactured by Catalyst Factory of Qi-Lu Petrochemical Incorporation, Shandong, China, and the physico-chemical properties thereof were shown in Table 2 RMG catalyst containing Y zeolite and ZSM - 5 zeolite is a catalyst for high yield of liquefied gas and gasoline. The fresh RMG catalyst was subjected to steam aging treatment at 760° C. under atmospheric pressure with 100% steam for 8 hours before the test was carried out, the aged catalyst had the micro-activity of 76. [0043]
The test steps were as follows: in a pilot FCC unit, the aforementioned light petroleum hydrocarbon was preheated, the injected into the riser reactor through a spaying nozzle, followed by contacting and reacting with the catalyst; the resultant mixture of the reaction product and the catalyst went upward to the outlet of the riser reactor, then the reaction product and catalyst were rapidly separated with each other, the oil gas entered the follow-up separation system via a transfer-oil-line: the carbon-deposited catalyst fell into a stripper, when the catalyst was stripped with steam and then transferred to a regenerator to burn off coke on the catalyst, and the regenerated catalyst was then fed back to the riser reactor for reuse through circulation. Each of the reaction products were counted and analyzed for their physicochemical properties. [0044]

The main reaction conditions and the test results were shown in Table 5 and 6. From Table 5 and 6, it can be observed that the total yield of gasoline and diesel oil product was more than 90% by weight after the light petroleum hydrocarbon was treated by the process provided in the present invention. Furthermore the contents of sulfur and nitrogen in the gasoline and diesel oil product were decreased to a great extent, and the olefin content of gasoline was decreased notably as well as the freezing point of diesel oil was reduced.

TABLE 2


Trademark (Brand)	ClP-3	RMG

Chemical Composition, wt %
Al₂O₃	52.0	42.5
Na₂O	0.09	0.16
Fe₂O₃	0.40	0.49
Apparent Density, Kg/m³	0.81	0.79
Pore Volume, ml/g	0.30	0.31
Specific Surface Area, M²/g	210	206
Attrition Index, wt/h⁻¹	1.6	0.9
Particle Size Composition, wt %
0˜40 μm	21.0	14.2
40˜80 μm	60.5	54.8
>80 μm	18.5	31.0
Steam Aging Condition	790° C. 4 hour	760° C. 8 hour
Micro-Activity, MA	66	76

TABLE 3


		Catalytic
		gasoline
Test Number	Example 2	feedstock

Reaction Pressure, Mpa	Atmospheric	/
	pressure
Reaction Temperature, ° C.	300	/
Catalyst-oil ratio	2.28	/
Space Velocity, hr⁻¹	60.44	/
Spraying Water, wt %	8.6	/
Regeneration Temperature, ° C.	500	/
Regeneration Time, min	20	/
Carbon Content of Spent Catalyst, wt %	1.26	/
Carbon Content of Regenerated Cat., wt %	0.38	/
Material Balance, wt %
Dry gas	0.05
Liquefied Gas	4.30	/
Gasoline	90.73	/
Diesel Oil	3.20	/
Coke	1.72	/
Total	100.00	/
Gasoline Properties		(Feedstock
		Properties)
S, mg/l	80	91
N, mg/l	3.3	30
Octane number (measured)
RON	89.3	89.2
MON	78.6	78.3
Paraffin, wt %	4.31	4.50
Iso-paraffin, wt %	32.75	25.69
Naphthene, wt %	9.98	8.72
		38.21
Olefin, wt %	25.75	22.89
Aromatics, wt %	27.17
Density, g/cm³(20° C.)	0.7361	0.7295
Actual Gum, mg/100 ml	2.0	3.0
Diene Value, gl₂/100 ml	1.2	1.8
Induction Time, min	516	409

TABLE 4


		Coking Diesel Oil
Test Number	Example 3	Feedstock

Reaction Pressure, Mpa	0.11	/
Reaction Temperature, ° C.	380	/
Catalyst-Oil Ratio	6	/
Space Velocity, hr⁻¹	16.7	/
Spraying Water, wt %	2.8	/
Regeneration Temperature, ° C.	530	/
Regeneration Time, min.	40	/
Carbon Content of Spent Cat., wt %	0.72	/
Carbon Content of Regenerated Cat., wt %	0.17	/
Material Balance, wt %
Dry gas	0.28	/
Liquefied Gas	4.36	/
Gasoline	10.64	/
Diesel Oil	81.62	/
Coke	3.10	/
Total	100.00	/
Diesel Oil Properties		(Feedstock
		Properties)
S, ppm	978	8225
N, ppm	129	5018
Density, g/cm³(20° C.)	0.8661	0.8520
Freezing Point ° C.	−13	−3
Actual Gum, mg/100 ml	93	189
Cetane Number	43	47

	TABLE 5


	Test Number	Example 4

	Reaction Pressure, MPa	0.11
	Reaction Temperature, ° C.	350
	Catalyst-Oil ratio	6.2
	Spraying Water, wt %	3.2
	Reaction Time, Sec	2.2
	Regeneration Temperature, ° C.	510
	Regeneration Time, min.	36
	Carbon Content of Spent Cat., wt %	0.83
	Carbon Content of Regenerated Cat., wt %	0.24
	Material Balance, wt %
	Dry gas	0.17
	Liquefied Gas	4.56
	Gasoline	73.87
	Diesel Oil	18.26
	Coke	3.14
	Total	100.00

TABLE 6


	Gasoline	Diesel Oil	Gasoline	Diesel Oil
Test Number	Feedstock	Feedstock	Product	Product

Density (20° C.) g/cm³	0.7461	0.8647	0.7574	0.8662
Viscosity (20° C.) mm²/s	/	4.78	/	3.65
Acid Value, mg	0.86	1.91	0.83	1.67
KOH/100 ml
S, ppm	1786	0.8%	863	48.0
N, ppm	64	0.5%	8	7.2
Freezing point, ° C.	/	−12	/	−18
Actual Gum, mg/100 ml	4.6	3.0	2.1	2.6
Olefin, vol. %	54.8	/	33.9	/
Diene Value, g I₂/100 g	1.6	/	0.5	/
Gasoline RON	90.2	/	90.0	/
MON	79.4	/	79.5	/
Cetane Number	/	48	/	45
Distillation range ° C.
Initial point	40	187	43	183
10%	60	221	64	219
30%	84	243	85	244
50%	116	261	119	262
70%	143	289	145	294
90%	169	326	175	330
End point	195	363	198	367

Claims

We claim:

1. A process for catalytically upgrading light petroleum hydrocarbons accompanied by low temperature regenerating the catalyst, characterized in that:

a) introducing the light petroleum hydrocarbons and the regenerated catalyst into a reactor to form a mixture of the feedstock and the catalyst;

b) catalytically converting the light petroleum hydrocarbon under the conditions of a temperature 200 to 450° C. a pressure of 0.1 -0.5 Mpa, a catalyst-oil ratio of 2 to 15 and a reaction time of 1 to 20 second to form a mixture of the resultant including gasoline, diesel oil and liquefied gas, and the spent catalyst;

c) separating the resultant and the spent catalyst;

d) stripping the spent catalyst;

e) regenerating the stripped spent catalyst for 10 to 50 minutes under a temperature of 400 to 600° C. and a pressure of 0.1 to 0.6 Mpa;

f) feeding the regenerated catalyst back to the reactor for reuse through circulation.

2. A process according to claim 1, characterized in that said light petroleum hydrocarbon is selected from a primary processing distillate oil, a secondary processing distillate oil and their mixture, and the light petroleum hydrocarbon has a distillation range from an initial boiling point to 400° C. in accordance with Engler distillation.

3. A process according to claim 1, characterized in that said light petroleum hydrocarbon is selected from one distillation cut or mixture consisting of more than one distillation cut comprising straight-run gasoline, straight-run diesel oil, coking gasoline, coking diesel oil, cracking gasoline, cracking light cycle oil, hydrogasoline or hydrogenation diesel oil.

4. A process according to claim 1, characterized in that the process is suitable for fluidized bed reactor, riser reactor, down-flow type reactor and any modified units based on the conventional catalytic. Cracking unit.

5. A process according to claim 1, characterized in that said reaction conditions for catalytically upgrading light petroleum hydrocarbons comprise: a reaction temperature of 200 to 400° C., a catalyst-oil ratio of 3 to 10, a reaction time of 2 to 10 second, a reaction pressure of 0.15 to 0.4 Mpa, a weight ratio of atomization steam to the light petroleum hydrocarbon of 0.01 to 0.2.

6. A process according to claim 1, characterized in that said stripped spent catalyst is regenerated under the following conditions: a regeneration temperature of 450 to 550° C., a regeneration time of 10 to 30 minutes and a regeneration pressure of 0.15 to 0.45 Mpa, the content of the excess oxygen in the regeneration flue gas is less than 5% volume, and the carbon content of regenerated catalyst is less than 0.7% by weight.

7. A process according to claim 6, characterized in that the content of the excess oxygen in the regeneration flue gas is less than 1% volume, and the carbon content of the regenerated catalyst is less than 0.5% by weight.

8. A process according to claim 1, characterized in that said catalyst contains high silicon zeolite with pentasil structure.

9. A process according to claim 1, characterized in that said regenerated catalyst is cooled in part or all in a cooler and then fed back to the reactor for reuse through circulation.

10. A process according to claim 1, characterized in that the overheated steam is used as a stripping medium during said stripping of catalyst, or a part of the regenerated catalyst can also be introduced to the stripper and mixed with the spent catalyst.