CN1046308C - Depth Selective Cracking Method of Distillate Oil - Google Patents

Abstract

A catalytic conversion method for producing low-carbon olefins and low-point diesel oil from distillate oil, using petroleum fractions at 215-420°C as raw materials, contacting with a solid acid catalyst in a fixed-bed reactor for deep selective cracking reaction, temperature 400-500℃, pressure≯0.5MPa, space velocity 0.5-10.0h ^-1 . The target product of this method is cracked gas rich in low-carbon olefins, and its yield can reach 40-45m%; the yield of low-point diesel oil is 42-50m%; the rest is high-octane gasoline blending components and a small amount dry air. The method has low reaction temperature and simple process equipment; in addition to obtaining higher yields of propylene and butene, more low-point diesel blending components can also be produced.

Description

Depth Selective Cracking Method of Distillate Oil

The invention belongs to the catalytic conversion method of petroleum hydrocarbons.

Specifically, the present invention uses refinery straight-run constant three-line, normal four-line, minus one-line distillate or its mixed fraction and straight-run gasoline, diesel oil and light hydrocarbons in refineries and oil fields as raw materials, through a ZSM-containing 5 High-silica zeolite solid acid catalyst, under certain conditions for deep selective cracking reaction, the target product is liquefied petroleum gas rich in low-carbon olefins and low freezing point light diesel blending components, and at the same time by-product high-octane gasoline adjustment Combined components and a small amount of heavy diesel oil and dry gas.

Widely used petrochemical raw materials such as ethylene, propylene, butene and other low-carbon olefins are usually produced by thermal decomposition of oilfield light hydrocarbons, refinery naphtha or light diesel oil under high temperature and harsh conditions in the presence of water vapor . In the refinery, the catalytic cracking unit that mainly produces fuel oil also produces a small amount of low-carbon olefins, but its output generally only accounts for 10-15m% of the cracked raw materials. The catalytic conversion of low-carbon alcohols into low-carbon olefins has not yet formed an industrial production scale. The method of large-scale production of low-carbon olefins is still dominated by steam cracking technology. The ethylene in the cracked gas can reach 34%, and there is also a lot of methane gas that is not easy to be further utilized, accounting for about 25% of the dry gas; steam cracking The reaction temperature is as high as above 800°C, the conditions are harsh, and the equipment investment is expensive. Therefore, new patents are constantly appearing in the study of new methods for producing low-carbon olefins by catalytic conversion of hydrocarbons. For example, US 3,541,179, US3,647,682 and DD 152,356 use alumina or amorphous silica-alumina as catalysts, and some load 0.5-20m% metals such as Cu, Mn, V, etc. Most of them use moving bed or fluidized bed reactors. C4, crude gasoline, middle distillate oil and vacuum gas oil are used as raw materials, and the reaction temperature is 600-750°C. The total yield of ethylene, propylene and butene is about 30m%, of which ethylene mainly accounts for about 45m%. . In recent years, high-silicon mesoporous zeolites have been developed as active components of catalysts such as: ZSM-5, ZSM-11, ZSM-12, ZSM-21, ZSM-23, ZSM-35, ZSM-38, etc. JP-A-60-222428 uses ZSM-5 to C5-C25 paraffin-based hydrocarbons, conducts cracking reaction at 600-730°C, WHSV=20-300h ^-1 , and normal pressure conditions, and the yield of C2-C4 olefins is 10.5-29.1m%; with naphtha as raw material, the yield of C2-C4 olefins is 31.9m%; with hydrogenated vacuum gas oil as raw material, the yield of C2-C4 olefins is 27m%. US 3,926,782 uses a catalyst containing 10m% REY, 10m% ZSM-5, and 80m% clay to crack gas oil in a small fixed fluidized bed in the laboratory, WHSV=5h ^-1 500°C, CRT=5 seconds, and the total yield of C4 22.6m%, dry gas 11.4m%, coke 4.7m%. GB2,034,352 uses H-ZSM-5 as a catalyst, takes petroleum distillate at 230-450°C as raw material, and converts it in a fixed-bed reactor. The reaction temperature is 260-430°C, LHSV=0.1-15h ^-1 , P=25psia , The yield of C3-C4 olefins is only 2-10m%. CN-87105428 Produces low-carbon olefins by fluidized catalytic cracking technology. The catalyst contains ZSM-5 zeolite, and vacuum gas oil is used as raw material. The reaction temperature is 500-650 ° C, and the yield of C3-C4 olefins can reach 42m%. Most of the above methods require a reaction temperature higher than 500°C, and the olefin yield is very low when the temperature is lower than 500°C. When the reaction temperature is higher than 500°C and a fluidized bed reactor is used, the equipment material requirements are high, and the process, process, and operation are relatively complicated.

The purpose of the present invention is to propose a kind of at lower reaction temperature, use specific solid acid catalyst, in fixed-bed reactor, take petroleum hydrocarbons as raw material, carry out depth selection at the deficiencies of the prior art above. A cracking reaction method; while preparing C3 and C4-based low-carbon olefins, it produces low-freezing-point diesel and high-octane gasoline blending components.

The catalyzer that the present invention uses is the solid acid catalyst that contains ZSM-5 zeolite, comprises three kinds of industrially produced commercial catalysts, and wherein catalyst A trade mark is CTL-1, and catalyst B trade mark is SKP-1, and A, B catalyst are all Produced for Shanghai Dyestuff No.7 Factory. The trade name of catalyst C is RDW-1, produced by Hunan Changling Refinery and Chemical Plant. The other four: D, E, and FG are catalysts prepared in the laboratory. D is a directly synthesized Fe-ZSM-5 catalyst; E is a directly synthesized Cr-ZSM-5 catalyst; F is a H-ZSM-5 catalyst with a silicon-aluminum ratio (mol) of 24; G is a catalyst made of triethylamine and bromine H-ZSM-5 catalyst with silicon-aluminum ratio (mol) greater than 200 for ethane synthesis. The carrier binders of the above seven catalysts are all artificially synthesized alumina. The code name, brand name and main physicochemical properties of the catalyst used in the present invention are listed in Table 1; the preparation conditions and preparation process of catalysts D, E, F, G are shown in Example 1.

Table 1 Catalyst code Catalyst name Molecular sieve content m% Alumina content m% Metal content m% Sodium oxide content m% Molecular sieve silicon aluminum ratio mol A CTL-1 65 35 ---- <0.1 60 B SKP-1 65 35 ---- <0.1 154 C RDW-1 65 35 Ni 1.0 <0.1 60 D. RZQ-1 65 35 Fe 1.5 <0.1 132 E. RZQ-2 65 35 Cr 0.5 <0.1 120 f RZQ-3 65 35 ---- <0.1 twenty four G RZQ-4 65 35 ---- <0.1 236

The raw material oil used in the present invention includes: refinery straight-run regular third-line, normal-fourth line and minus-first-line distillate or mixed fractions; also includes straight-run gasoline, diesel oil, light hydrocarbons in refineries and oilfields. For the process of producing low-carbon olefins, it is best to use these fractions obtained from the processing of paraffin-based crude oil, because the mechanism of the depth selective cracking reaction is to use the unique pore structure of the high-silica zeolite solid acid catalyst and the characteristics of the protonic acid on the surface. Linear alkanes in petroleum fractions undergo shape-selective cracking to generate more small-molecule alkenes and alkanes. The higher the wax content in the raw oil, the higher the yield of gas olefins; for the production of low-point diesel oil, the petroleum fraction with low wax content can be selected as the raw material, and a higher yield of low-point diesel oil can be obtained. But the corresponding yield of low carbon olefins is also low. Several feed oils and properties used by the present invention are listed in Table 2.

The reaction conditions of the present invention include: the reaction temperature is 400-500°C, the reaction pressure is not more than 0.5MPa (table), and the weight space velocity is 0.5-10.0h ^-1 . The reaction temperature range is different from the high-temperature catalytic cracking technology that mainly produces ethylene, and is also different from the low-temperature catalytic dewaxing process that mainly produces low-condensation diesel. In the process of deep selective cracking reaction, as the reaction time increases, the carbon area on the catalyst surface gradually increases, and its selective cracking activity decreases slowly. In order to maintain a certain conversion rate, the reaction temperature must be gradually increased to compensate for the attenuation of catalyst activity, so as to achieve Requirements for target product yield and freezing point depression of diesel. The influence of reaction pressure on the depth selective cracking reaction is mainly manifested in the influence on the secondary cracking selectivity of gasoline fraction. 0.5MPa (Table) Compared with normal pressure, the liquid product yield is 5-6 percent higher. As the pressure increases, the yield of cracked gas decreases, and the macromolecular jelly in the liquid product increases, which leads to an increase in the carbon deposition rate of the catalyst and a significant shortening of the reaction cycle. Therefore, the design and operation of industrial units should reduce the system pressure drop as much as possible to prolong the reaction cycle.

Table 2 Ordinary third-line distillate Minus first-line distillate straight run gasoline straight run diesel light hydrocarbon Density 20℃kg/ml 0.8351 0.8406 0.7313 0.7919 0.7115 Viscosity 20℃mm/s 7.87 5.38 ---- 3.75 ---- Freezing point ℃ 33.0 22.0 ---- -1.0 ---- Acid value mgKOH/g 0.0 0.05 0.10 0.27 ---- Aniline point ℃ 100.7 89.5 ---- 85.5 ---- Sulfur content ppm 548.0 564.0 <0.01 ---- 130 Alkaline nitrogen content ppm 86 93 ---- ---- ---- Distillation range ℃ initial boiling point 295 215 51 184 39 5% 345 287 73 201 10% 357 301 84 209 30% 377 335 107 231 50% 387 353 123 256 115 70% 397 370 137 286 90% 413 396 160 327 200 95% 420 410 169 341 220 dry point 425 415 195 354 225

The selection of a suitable reaction space velocity is beneficial to suppress the hydrogen transfer reaction and increase the yield of propylene and butene in the cracked gas. The process conditions of the present invention are: reaction temperature 400-550 ℃, preferably 420-500 ℃; reaction pressure is not more than 0.5MPa (table), preferably 0.2-0.4MPa (table); weight space velocity is 0.5-10.0 h ^-1 , preferably 1.0-3.0h ^-1 .

The technological schematic flow sheet of the present invention is shown in Fig. 1, now main technological process is described as follows in conjunction with Fig. 1: raw material oil is sent into heat exchanger 3 with pump 2 through buffer tank 1, enters heating furnace 4 after exchanging heat with reaction product, heating When the reaction temperature reaches the reaction temperature, it enters the first reactor 5 to contact with the catalyst to carry out the deep selective cracking reaction. Since the cracking of hydrocarbons is a strong endothermic reaction, the catalyst bed has a temperature drop of about 60-70 ° C, and the reaction intermediate product enters the thermal Separator 6, the cracked gas is separated from the top of the separator to the separator tank 12. The liquid product enters the second heating furnace 7 from the bottom of the separator to be heated to the reaction temperature and then enters the second reactor 8 to continue the reaction. The cracked product enters the fractionation tower 9 through the heat exchanger 3, and the cracked gas and gasoline pass through the cooler 10 from the top of the tower. Enter the oil-gas separator 11, separate the pyrolysis gas from the top, enter the liquid separation tank 12, and then enter the air compressor 13 from the top, and then enter the separation tank 14 after one-stage compression. Enter the separation tank 15 top to separate the dry gas, and the bottom to go out the liquefied gas. Gasoline passes through the pump 18 from the lower part of the separator 11, a part goes to the top of the fractionating tower as reflux, and the rest goes out of the device. Diesel oil at the bottom of the fractionation tower is taken out by a pump 16, and then goes out of the device through a heat exchanger 3 and a cooler 17.

Features and advantages of the present invention are:

1. The invention uses the ZSM-5 with high silicon-aluminum ratio synthesized by triethylamine and bromoethane as the catalyst active component, which enhances the stability of deep selective cracking reaction of distillate oil and reduces catalyst carbon deposit.

2. The present invention adopts suitable reaction space velocity to reduce the hydrogen transfer reaction of the process; appropriately raises the reaction temperature to increase the yield of low-carbon olefins, mainly propylene and isobutene, and reduces the yield of dry gas, which is a great contribution to the petrochemical industry. Provide more low-carbon olefin raw materials.

3. Compared with the existing catalytic cracking and steam cracking for producing low-carbon olefins, the present invention has a lower reaction temperature of 100-300°C, lower requirements for equipment materials, and does not need to use expensive high-alloy steel; in addition, because the present invention adopts fixed bed reaction device, the reaction pressure is low, the process is relatively simple, and the installation and equipment are also easy to solve.

4. The technical method of the present invention produces low-freezing-point diesel oil blending components while producing low-carbon olefins. In addition, by changing the operating conditions, the ratio of the two main products can be adjusted within a certain range, and the production flexibility is strong.

5. The process of the present invention can be combined with catalytic cracking in oil refineries to form a new combined process, which can share fractionation, absorption, and stable systems: the combined process can save investment, reduce energy consumption, expand catalytic cracking processing capacity, and increase low-carbon Olefin production.

6. The raw material used in the present invention is mainly waxy middle distillate oil, which is not suitable for being used as raw material for catalytic cracking because of its light distillation range; and because of its high freezing point, it cannot be directly used as light diesel oil. So the raw material used in the present invention can be said not to compete with the backbone process catalytic cracking of the refinery for the raw material.

Example 1

This embodiment has described the laboratory preparation condition and the preparation process of catalyst D, E, F, G:

1. Preparation of Catalyst D

Molecular sieve synthesis: add 250 grams of water glass (27.62% SiO ₂ , 8.71% Na ₂ O) 82 grams of water and 89.4 milliliters of ethylamine aqueous solution (concentration is 0.243 grams/ml) in the synthesis kettle to make solution I, in a beaker Weigh 10 grams of ferric nitrate (Fe(NO ₃ ) ₃ 9H ₂ O), 25.1 milliliters of sulfuric acid (concentration is 0.8786 g/ml) and 120 grams of water to make solution II, then add solution II to solution I under stirring Add 1 gram of ZSM-5 as a seed crystal, stir well, close the kettle and raise the temperature to crystallize, crystallize at 145°C for 44 hours, cool the crystallized product, wash it with deionized water until pH = 8-9, and put it in Dried at 120°C, analyzed by X-ray diffraction as ZSM-5. Catalyst preparation: take 30 grams of molecular sieve prepared above, exchange with 5% ammonium chloride aqueous solution (add 5ml ammonium chloride aqueous solution per gram of molecular sieve), exchange for 1 hour at 90-100 ° C, exchange 2 times in total, wash with deionized water To be free of chloride ions and dry, weigh 20 grams of the exchanged sub-sieve, add 16.4 grams of aluminum hydroxide, knead and extrude with 5% nitric acid solution after mixing to form (φ1.0×5.0-10.0mm), and then After drying and calcining at 540°C for 4 hours, catalyst D was obtained.

2. Preparation of Catalyst E

Molecular sieve synthesis: add 240 grams of water glass (27.24% SiO ₂ , 8.76% Na ₂ O) 240 grams of water and 14 grams of tetraethylammonium iodide in the synthesis kettle to make solution I, add 71 milliliters of chromium sulfate ( Cr ₂ (SO ₄ ) ₃ ·6H ₂ O concentration is 0.8266 g/ml), 19.6 ml of sulfuric acid aqueous solution (concentration is 1.034 g/ml) and 188 g of water are mixed to make solution II, and then solution II is added to In solution I, add 0.8 g of ZSM-5 as a seed crystal, stir well, seal the kettle and raise the temperature to crystallize at 165°C for 20 hours, and the crystallized product is cooled and washed with deionized water until pH = 8-9. Dried at 120°C, analyzed by X-ray diffraction as ZSM-5. The preparation method of catalyst E is the same as that of catalyst D.

3. Preparation of Catalyst F

Molecular sieve synthesis: add 300 grams of water glass (29.47% SiO ₂ , 9.28% Na ₂ O) 27.3 milliliters of ethylamine aqueous solution (concentration is 0.243 grams/ml) and 300 milliliters of water in the synthesis kettle and mix to make solution I, in addition 32.71 gram of aluminum sulfate (AI ₂ (SO ₄ ) ₃ 18H ₂ O), 16.6 milliliters of sulfuric acid solution (concentration of 0.9959/ml) and 359 grams of water were mixed to make solution II, and then solution II was added to solution I under stirring , then add 1.0 g of ZSM-5 as a seed crystal, stir well, close the kettle and raise the temperature to crystallize, and crystallize at 165°C for 45 hours, the crystallized product is cooled, washed with deionized water to PH = 8-9, and heated at 120°C It was dried at ℃ and analyzed by X-ray diffraction as ZSM-5. The preparation method of catalyst F is the same as that of catalyst D.

3. Preparation of Catalyst G

Molecular sieve synthesis: add 300 grams of water glass (29.47% SiO ₂ , 9.28% Na ₂ O) and 200 milliliters of water in the synthesis kettle to mix to make solution I, and add 35.7 milliliters of sulfuric acid solution (concentration is 0.9959/ml) and 220 grams of Mix with water to make solution II, add solution II to solution I under stirring, then add 17.85 g triethylamine, 19.25 g bromoethane, 20 g ethanol and 1.0 g ZSM-5 seed crystal, stir well and put the kettle Enclosed and heated to crystallize, crystallize at 150°C for 32 hours, the crystallized product is cooled, washed with deionized water to pH=8-9, dried at 120°C, and analyzed by X-ray diffraction as ZSM-5. The preparation method of catalyst G is the same as that of catalyst D.

Example 2

This example illustrates the product distribution and conversion rate of deep selective cracking of distillate oil on several solid acid catalysts. The raw material is ordinary third-line distillate oil, and the depth selective cracking reaction is carried out in a small fixed-bed reactor. The specific reaction conditions are: temperature 450°C, weight space velocity 2.0h ^-1 , normal pressure, and the average results of continuous reaction for 100h are listed in the table 3.

table 3 Catalyst A B C D. E. f Product distribution m% Cracked gas where: C2=C3=C4=∑C2=+C3=+C4=∑C3+C4C5-200℃ fraction>200℃ fraction conversion rate m%* 39.54.2030.138.672.994.816.244.355.7 34.92.6733.042.077.796.517.847.352.7 38.06.0527.234.968.294.315.646.453.6 34.92.3533.242.978.596.715.649.550.5 37.75.7223.826.956.490.716.346.054.0 38.95.1829.435.470.093.714.047.152.9 *Conversion=(100-diesel fraction yield)m%

Example 3

This example illustrates the product distribution of deep selective cracking of distillate oil at different reaction temperatures. The raw material is still ordinary third-line distillate oil, and the catalyst is G. The test conditions and results are listed in Table 4.

Table 4 Reaction temperature °C 460 480 500 Weight space velocity h ^-1 Reaction pressure MPa Product distribution (to raw material) m% H2CH4C2H6C2H4C3H8C3H6iC4H10nC4H10iC4H8uC4H8tC4-2cC4-21,3-C4H6∑C2=+C3=+C4=∑C3+C4(LPG)∑H2+C1+C2(dry Gas) C5-200°C gasoline fraction>200°C diesel fraction 1.00.00.020.130.391.343.5814.741.162.688.262.694.243.050.0234.3440.421.8812.6045.10 1.00.00.060.250.642.193.8516.101.212.497.472.444.092.980.0335.3040.663.1413.1043.10 1.00.00.080.280.652.402.5818.870.451.817.712.714.203.030.0338.9541.393.4113.2042.00

Example 4

This example illustrates the product distribution of deep selective cracking of distillate oil under different reaction space velocities. The raw material is still ordinary third-line distillate oil, and the catalyst is G. The test conditions and results are listed in Table 5.

table 5 Reaction space velocity h ^-1 (m) 2.90 2.03 1.00 Reaction temperature ℃ Reaction pressure MPa Product distribution m% (to raw material) H2CH4C2H6C2H4C3H8C3H6iC4H10nC4H10iC4H8nC4H8tC4-2cC4-21,3-C4H6∑C2=+C3=+C4=∑C3+C4(LPG)∑H2+C1+C2(dry gas)C5 -200°C gasoline fraction>200°C diesel fraction 5000.00.070.250.562.122.2815.680.401.606.822.403.722.670.0334.4436.603.009.1051.30 5000.00.040.330.812.493.5315.421.012.116.612.343.112.750.0332.7236.913.6711.9247.50 5000.00.080.280.652.402.5818.870.451.817.712.714.203.030.0338.9541.393.4113.2042.00

Example 5

This example illustrates the product distribution of different depth selective cracking of feedstock oils. The feedstocks are the normal three-line distillate oil, the reduced first-line distillate oil, straight-run gasoline, straight-run diesel oil and light hydrocarbons in Table 2, the catalyst is A, and the test conditions and results Included in Table 6.

Table 6 raw material Ordinary third-line distillate Minus first-line distillate straight run gasoline straight run diesel Light hydrocarbon Reaction temperature °C Reaction space velocity h ^-1 Reaction pressure MPa Product distribution m% (for raw materials) H2CH4C2H6C2H4C3H8C3H6iC4H10uC4H10iC4H8uC4H8tC4-2cC4-21,3-C4H6∑C2=+C3=+C4=∑C3+C4(LPG)∑H2+C1+ C2C5-200℃gasoline＞200℃diesel fraction 4502.00.00.100.150.422.768.787.306.605.611.023.531.821.300.0017.7335.783.4320.5040.29 4502.00.00.120.630.913.317.767.195.424.991.023.122.061.460.0218.1833.044.9719.6942.30 4502.00.00.190.361.612.5110.515.204.304.940.582.000.990.710.0011.9929.234.6766.10---- 4502.00.00.220.731.923.8912.198.677.677.430.833.112.211.630.0020.3443.746.7622.3027.20 5002.50.00.400.532.968.617.6215.742.093.244.271.512.322.000.0034.4538.7912.5048.71----

Example 6

This embodiment illustrates the different results of one-stage reaction and two-stage reaction of depth selective cracking. Catalyst (G) is divided into two reactors according to a certain proportion. The raw material used in the test is ordinary third-line distillate oil. The test conditions and results are listed in Table 7. Under the condition that the total space velocity of the two-stage reaction is the same as that of the first-stage reaction, since the cracked gas is separated in the middle of the two-stage reaction, it is beneficial to increase the yield of the cracked gas, and the low-carbon olefins and liquefied gas in the cracked gas The yields of both also increased significantly while the dry gas did not increase much.

Table 7 reactive form two sections section Reaction temperature °C Reaction space velocity h ^-1 Reaction pressure MPa Product distribution m% (for raw materials) H2CH4C2H6C2H4C3H8C3H6iC4H10nC4H10iC4H8nC4H8tC4-2cC4-21,3-C4H6∑C2=+C3=+C4=∑C3+C4(LPG)∑H2+C1+ C2C5-200℃gasoline＞200℃diesel fraction 4501.00.00.040.110.241.595.1215.812.104.057.532.004.983.570.0135.4845.161.9816.7536.10 4501.00.00.030.090.201.384.4213.651.813.496.501.734.303.080.0130.6538.991.7017.5141.80

Example 7

This embodiment illustrates, the result of the long-term operation of the deep selective cracking two-stage reaction, the raw material used in the test is the common third line distillate oil, the catalyst is (G), the loading amount of the two reactor catalysts is 30g altogether, the first reactor and the first reactor 2 The filling ratio of the reactor is 1:3 (m), the total WHSV=1.0h ^-1 , the continuous reaction at normal pressure is 1071h, the initial reaction temperature is 400°C, the reaction temperature is 440°C for 953h, and the reaction temperature is 954h to 1071h and airspeed conditions. The reaction process controls the conversion rate of distillate oil to ≮50m%, and the yield of cracked gas to ≮40m%. As the reaction time prolongs, the catalyst is slowly deactivated due to carbon deposits. In order to maintain a certain conversion rate, the reaction temperature must be increased accordingly. The relationship between the temperature rise curve of the long-term reaction and the corresponding product yield and the freezing point of diesel oil is shown in Figure 2. Among them, curves 1, 2, 3, and 4 represent the variation curves of diesel fraction, liquefied petroleum gas, gasoline fraction, and diesel freezing point, respectively. The relationship between reaction temperature and conversion rate and product distribution is shown in Figure 3, wherein curves 1, 2, 3, 4, and 5 represent the changes of diesel fraction, conversion rate, liquefied petroleum gas, low-carbon olefins in cracked gas, and gasoline fraction respectively curve. The relationship between reaction space velocity and conversion rate and product distribution is shown in Figure 4, where curves 1, 2, 3, 4, and 5 represent: conversion rate, diesel fraction, liquefied petroleum gas, light olefins in cracked gas, and gasoline fraction change curve. The properties of large samples of gasoline and diesel products in the long-term test are listed in Table 8.

Table 8 gasoline diesel fuel Density (20℃)kg/ml 0.7713 0.8726 Colloid mg/100ml --- 201 Viscosity V2mm ² /s --- 13.69 Freezing point ℃ --- -41 Flash point ℃ --- 119 Acidity mgKOH/100ml 4.1 6.3 Corrosion (100℃, 3h) 1a 1a Induction period min 30 --- Aniline point ℃ --- 73.6 Sulfur content ppm 57.0 724 Nitrogen content ppm 13.6 168 Distillation range °C initial boiling point 45 239 10% 69 289 50% 117 324 70% 132 331 90% 155 343 dry point 201 351 Octane number CMON 80.3 CRON 90.1 cetane number CN 44.2 Sediment mg/100ml 0.86

Claims (3)

1. A method for catalytic conversion of hydrocarbons to produce low-carbon olefins and low-point diesel oil, characterized in that the process includes: (1) After the raw material oil is heated, it enters the first fixed-bed reactor, and is mixed with ZSM-5 containing Si/Al>200 under the conditions of temperature 400-500°C, pressure ≯0.5MPa, and space velocity 0.5-10.0h ^-1 Molecular sieve catalyst is contacted to carry out deep selective cracking reaction. (2) The intermediate product generated by the (1) step cracking reaction enters the separator, wherein the cracked gas is separated from the top of the separator, and the liquid product is extracted from the bottom of the tower, (3) the liquid product that is drawn out by (2) step enters the ZSM-5 molecular sieve catalyst fixed-bed reactor that second Si/Al＞200 is equipped with, cracking reaction takes place under the same condition with (1) step, (4) The pyrolysis reaction product obtained in step (3) enters the fractionation tower, and the cracked gas and gasoline mixture containing C ₃ ^- +C ₄ ^- separated from the top of the tower enters the oil-gas separator for further separation, and low-condensation diesel oil comes out from the bottom of the tower. 2. The method according to claim 1, characterized in that the ZSM-5 molecular sieve is a HZSM-5 molecular sieve with Si/Al>200 synthesized by triethylamine and oethane. 3. According to the method according to claim 1, it is characterized in that the raw materials used include distillate oil or its mixed oil with a distillation range of 215 to 420° C. of the third line, the fourth line, and the first line, as well as straight-run gasoline, diesel oil, light oil, etc. hydrocarbon.

Images