CN1180055C - A needle coke production method for removing solid particles in raw oil - Google Patents

Abstract

The present invention relates to a method for preparing acicular coke to remove solid particles from raw oil. Catalytically cracked oil slurry and coked fractional oil enter at least one thermal settling device, and the settled oil slurry and optional other needle coke raw materials enter the bottom of a coking fractional column. Preheated clarified oil and optional other needle coke raw materials enter the heating furnace and enter a coke tower for reaction after temperature change operations, needle coke settles in the coke tower, coking oil gas is separated, wherein a part of gasoline and/or a part of diesel oil enter the thermal settling device. The method reduces the viscosity of the oil slurry via the low viscosity distillation oil in the delayed coking device and effectively increases the deprivation rate of solid particles, and therefore, the method can produce qualified needle coke.

Description

A needle coke production method for removing solid particles in raw oil

The present invention belongs to a method for the non-catalytic thermal cracking of hydrocarbon oils in the absence of hydrogen, more specifically, a method for producing needle petroleum coke.

The conventional needle coke production method is as follows: After the raw material oil is preheated by the heat exchanger and the convection section of the heating furnace, it first enters the bottom of the fractionation tower, and exchanges heat with the coked oil gas from the top of the coke tower in the fractionation tower. After being mixed with heavy distillate oil, it is pumped into the radiant section of the heating furnace for temperature-variable operation. The temperature range is 430-520°C, and the circulation ratio is 0.2-1.2. The heated raw oil enters the coke tower for coking reaction, and the pressure at the top of the coke tower is 0.1 ~ 3.0MPa, coke tower top temperature 380 ℃ ~ 460 ℃, needle coke stays in the coke tower, generally after 24 hours, switch to another coke tower to continue coking. The generated coke oil gas overflows from the top of the coke tower and enters the bottom of the fractionating tower to exchange heat with the raw material oil. After fractionation, the gas, gasoline, diesel and gas oil are extracted.

Needle coke production technology is based on the formation mechanism of small mesophase spheres. Generally, the raw materials used are rich in aromatics, such as catalytic cracking oil slurry, thermal cracking residue, lubricating oil furfural refined extract oil or ethylene tar. Among them, catalytic cracking oil slurry is used as a raw material, and solid impurities such as catalyst powder must be removed first, otherwise it will have an adverse effect on the growth of mesophase pellets in the production process of needle coke, and it is also not conducive to the fusion of mesophase pellets into a wide-area intermediate. Mutually.

There are about five methods for removing solid particles (mainly catalyst powder) in FCC oil slurry: natural sedimentation, flocculation sedimentation, electrostatic separation, filtration separation and centrifugal separation. They mainly use the difference in density between solid particles and solutions in suspension to separate.

USP 4,407,707 discloses a method for removing solid particles in hydrocarbon oil, the method is to add sulfonic acid or sulfonate to hydrocarbon oil, and then separate the solid particles through water washing. In this method, instead of settling out of the oil, the solid particles are transferred to the water and settled again. Although it is more effective to wash out the solid particles with water, the industrial application is hindered by the difficult process.

USP4,686,048 discloses a method for removing catalyst powder in FCC oil slurry. First, dilute the oil slurry with hydrocarbon oil with a boiling point lower than 100°C, then filter and wash to separate the catalyst powder with an oil content of 2%, and separate it by distillation The diluent in the oil slurry is removed, and the obtained oil slurry is used as a carbon black raw material.

USP4,919, the method disclosed in USP4,919,792 to remove catalyst powder in fluid catalytic cracking (FCC) is to add coal, coke, FCC catalyst, moving bed catalytic cracking (TCC) catalyst, alumina Or silica and other sedimentation agents, which can promote the rapid sedimentation and removal of catalyst powder. Settling can be done in a slurry settler or centrifuge.

USP 5,593,572 discloses a method for removing spent catalyst powder in FCC oil slurry, adding a sufficient amount of heteroatom punctuated aliphatic polymer to the oil slurry for separation by flocculation and sedimentation.

USP5,645,711 discloses a combined process that passes coker gas oil through a solid-liquid separation device to improve the properties of coker gas oil by removing coke powder and solid particles in the gas oil, thereby achieving improved catalytic cracking and hydrotreating operating cycle of the device.

WO97/04042 discloses a method for separating water-insoluble solid particles from hydrocarbon oils. Alkylphenol ethoxylate is used as a flocculant, and an effective dose is added for sedimentation and separation. The solid content in the oil slurry is reduced to below 500ppm, and the oil slurry can be used as a carbon black raw material.

The purpose of the present invention is to provide a needle coke production method for removing solid particles in raw oil.

The method provided by the invention comprises:

The catalytic cracking oil slurry and coking distillate oil enter at least one heat settler, the settling temperature is 80-200°C, and the settling time is 8-36 hours. The catalytic cracking oil slurry (referred to as clarified oil) after removing solid particles The other needle coke raw materials enter the bottom of the coking fractionation tower together for preheating, and at the same time separate the coking fraction oil in the clarified oil;

The clarified oil from the bottom of the coking fractionation tower and other optional needle coke raw materials enter the heating furnace through temperature-variable operation, and the temperature range is 430-520°C, and then enter the coke tower for deep thermal cracking reaction. The inlet temperature of the coke tower is 460～510℃, coke tower top pressure is 0.1～3.0MPa, coke charging time is 16～40 hours, the needle coke formed by the reaction is deposited in the coke tower;

The coked oil gas from the top of the coke tower enters the fractionation tower to separate gas, gasoline, diesel oil, and gas oil. Part of the gasoline and/or part of the diesel oil enters the heat settler. This part of gasoline and/or diesel oil can enter the heat settler separately and be combined with The catalytic cracking oil slurry is statically mixed, and it can also be dynamically mixed with the catalytic cracking oil slurry before entering the heat settler.

In the method provided by the present invention, the coking distillate oil entering the heat settler has a boiling point range of 150-430°C. When the coking distillate oil is relatively light, such as with a boiling point of 150-200°C, it is better to choose a lower settling temperature, such as 80-150°C, otherwise the lighter distillate oil will be gasified and will not be able to dilute the catalytic cracking oil slurry; When the coking distillate oil is relatively heavy, such as with a boiling point of 200-430°C, it is better to choose a higher settling temperature, such as 150-200°C. A higher settling temperature is beneficial to dilute the catalytic cracking oil slurry. The weight ratio of the distillate oil to the catalytic cracking oil slurry is 0.01-0.6:1.

Other needle coke raw materials are selected from vacuum residue, atmospheric residue, catalytic cracking clarified oil, heavy crude oil, ethylene tar, lubricating oil extraction oil and thermal cracking residue, or a mixture of more than one. In the method provided by the present invention, other needle coke raw materials may be used or not.

When the needle coke raw material is a single catalytic cracking oil slurry, at least two heat settlers are used, generally two to four, and the oil slurry in one of the heat settlers is used as the needle coke raw material after settling, and it is switched during heat settling For recycling, the oil slurry in other heat settlers settles for standby use.

When the needle coke raw material has other needle coke raw materials besides catalytic cracking oil slurry, only one heat settler can be used, and the size of the heat settler is determined according to the relative ratio of catalytic cracking oil slurry and other needle coke raw materials. It is also possible to use more than one heat sink, and its operation method is the same as that of the single needle coke feedstock described above.

The method provided by the present invention will be further described below in conjunction with the accompanying drawings.

The accompanying drawing is a schematic diagram of a needle coke production method for removing solid particles in raw oil provided by the present invention, but it does not limit the method provided by the present invention.

The catalytic cracking oil slurry enters the heat settler 2 through the pipeline 1 and the coking distillate oil from the pipeline 22, the settled residual oil exits the device through the pipeline 4, and the oil slurry after removing solid particles is drawn out through the pipeline 3, separately or together with the oil from the pipeline 5 and other needle coke raw materials enter the bottom of the coking unit fractionation tower 8 through the pump 6 and the pipeline 7 in sequence. In the coking fractionation tower 8, the coking distillate component contained in the miscella after removing solid particles is separated and recycled.

The raw oil from the bottom 8 of the coking fractionation tower enters the heating furnace 12 through the pipeline 9, the pump 10 and the pipeline 11 in sequence, and after being heated to 430-520°C, it enters the coke tower 14 through the pipeline 13 for deep thermal cracking reaction, and the coke The inlet operating temperature of the tower is 460-510°C, the coke tower top pressure is 0.1-3.0MPa, and the coke charging time is 16-40 hours. The needle coke produced by the reaction is deposited in the coke drum. After coke full switching, decoking is carried out by conventional delayed coking hydraulic decoking system.

The coked oil gas enters the fractionating tower 8 through the pipeline 15 and is fractionated into gas, gasoline, diesel oil and gas oil, which are respectively discharged from the device through the pipelines 16, 17, 18 and 19, and part of the gasoline enters the heat settler 2 through the pipelines 20 and 22 successively, and/ Or part of the diesel oil enters the heat sink 2 through pipelines 21 and 22 in turn. This part of gasoline and/or diesel can be statically mixed with the oil slurry after entering the heat settler alone, or can be dynamically mixed with the oil slurry before entering the heat settler. The specific distillation range and quantity of this part of gasoline and/or diesel oil can be determined by actual operation.

The method advantage provided by the invention is:

1. The present invention effectively reduces the viscosity of raw oil through the mixing of low-viscosity coking distillate oil and raw oil, greatly improves the solid particle removal efficiency of the heat settler, and the ash removal rate reaches more than 80%;

2. The present invention does not need additional low-viscosity distillate components, and the required low-viscosity substances come from the coking distillate produced by the delayed coking unit, which eliminates the need for external supplementary components in the operation of the combined unit;

3. The low-viscosity coking distillate oil blended with raw material oil in the present invention can be recycled. Since the mixed oil enters the bottom of the coking fractionation tower for fractionation after the solid particles are removed, the coking distillate contained therein can be separated first and then recycled. use.

The following examples will further illustrate the method, but the method is not limited thereby.

Comparative example 1

This comparative example illustrates the situation that the catalytic cracking oil slurry is directly coked to produce needle coke without separating solid particles.

The catalytic cracking oil slurry first enters the bottom of the coking fractionation tower and is preheated by coking distillate oil, then enters the heating furnace and undergoes variable temperature operation, the temperature range is 430-520°C, and then enters the coke tower for deep thermal cracking reaction. The temperature is 460～510℃, the coke tower top pressure is 0.3MPa, and the coke charging time is 24 hours. The coke generated by the reaction is deposited in the coke tower, and the coked oil gas from the top of the coke tower enters the fractionation tower for separation to obtain gas, gasoline, diesel oil, gas oil.

The properties of oil slurry and coke are shown in Table 1. As can be seen from Table 1, the viscosity of oil slurry is 51.24mm ² /s, the ash content (tested according to the method provided by GB/T 508, the same below) is 3300ppm, and the The coefficient of thermal expansion (abbreviated as CTE, tested according to the carbon rod sample preparation method at 1000°C, the same below) is 2.71×10 ^-6 /°C, which is unqualified as a needle coke product.

Comparative example 2

This comparative example shows that the catalytic cracking oil slurry is separated from solid particles, but no coking distillate is added to dilute it to produce needle coke.

The catalytic cracking oil slurry first enters two heat settlers, settles at 150°C for 24 hours, and the catalytic cracking oil slurry after removing solid particles enters the bottom of the coking fractionation tower. Operation, the temperature range is 430-520°C, and then it enters the coke tower for deep thermal cracking reaction. The inlet temperature of the coke tower is 460-510°C, the pressure at the top of the coke tower is 0.3MPa, and the coke charging time is 24 hours. The reaction produces The coke is deposited in the coke tower, and the coked oil gas from the top of the coke tower enters the fractionation tower to be separated to obtain gas, gasoline, diesel oil, and gas oil.

The properties of clarified oil and coke are shown in Table 1. It can be seen from Table 1 that the viscosity of clarified oil is still 51.24 mm ² /s, the ash content is reduced to 690 ppm, and the ash removal rate is 79.1%; the CTE of coke is 2.63 ×10 ^-6 /℃, it is unqualified as a needle coke product.

Example 1

The catalytic cracking oil slurry and coked diesel oil enter into two heat settlers at a weight ratio of 10:1, the settling temperature is 150°C, and the settling time is 24 hours. After the solid particles are removed, the catalytic cracking oil slurry enters the bottom of the coking fractionation tower for Preheating, and at the same time separate the coked diesel oil in the clarified oil; the clarified oil from the bottom of the coking fractionation tower enters the heating furnace and undergoes temperature-variable operation. The inlet temperature of the coke tower is 460-510°C, the pressure at the top of the coke tower is 0.7MPa, and the coke charging time is 24 hours. The needle coke produced by the reaction is deposited in the coke tower; the coke oil gas from the top of the coke tower enters the fractionation tower to separate Gas, gasoline, diesel, gas oil, some of which enter the heat sink.

The test results are listed in Table 2. It can be seen from Table 2 that the viscosity of the clarified oil drops from 51.24mm ² /s before sedimentation to 30.18mm ² /s, and the ash content of the clarified oil drops from 3300ppm before sedimentation to 580ppm. The removal rate is 82.4%. The CTE of coke is 2.58×10 ^-6 /℃, which can be regarded as a qualified needle coke product. However, in Comparative Example 2, no qualified needle coke product was obtained because coker distillate oil was not added for dilution during heat settling.

Example 2

The catalytic cracking oil slurry and coked diesel oil enter into two heat settlers at a weight ratio of 10:2, the settling temperature is 90°C, and the settling time is 32 hours. The catalytic cracking oil slurry after removing solid particles enters the bottom of the coking fractionation tower for Preheating, and at the same time separate the coked diesel oil in the clarified oil; the clarified oil from the bottom of the coking fractionation tower enters the heating furnace and undergoes temperature-variable operation. The inlet temperature of the coke tower is 460-510°C, the pressure at the top of the coke tower is 0.7MPa, and the coke charging time is 24 hours. The needle coke produced by the reaction is deposited in the coke tower; the coke oil gas from the top of the coke tower enters the fractionation tower to separate Gas, gasoline, diesel, gas oil, some of which enter the heat sink.

The test results are listed in Table 2. It can be seen from Table 2 that the viscosity of the clarified oil drops from 51.24mm ² /s before sedimentation to 19.30mm ² /s, and the ash content of the clarified oil drops from 3300ppm before sedimentation to 420ppm. The removal rate is 87.3%. The CTE of coke is 2.56×10 ^-6 /℃, which can be regarded as a qualified needle coke product.

Example 3

FCC oil slurry and coked diesel oil enter into two heat settlers at a weight ratio of 10:3, the settling temperature is 90°C, and the settling time is 16 hours. The FCC oil slurry after removing solid particles enters the bottom of the coking fractionation tower for Preheating, and at the same time separate the coked diesel oil in the clarified oil; the clarified oil from the bottom of the coking fractionation tower enters the heating furnace and undergoes temperature-variable operation. The inlet temperature of the coke tower is 460-510°C, the top pressure of the coke tower is 1.0MPa, and the coke charging time is 24 hours. The needle coke produced by the reaction is deposited in the coke tower; the coke oil gas from the top of the coke tower enters the fractionation tower to separate Gas, gasoline, diesel, gas oil, some of which enter the heat sink.

The test results are listed in Table 3. It can be seen from Table 3 that the viscosity of the clarified oil drops from 51.24mm ² /s before sedimentation to 12.73mm ² /s, and the ash content of the clarified oil drops from 3300ppm before sedimentation to 280ppm. The removal rate is 91.5%; the CTE of the coke is 2.54×10 ^-6 /℃, which can be regarded as a qualified needle coke product.

Example 4

Catalyzed cracking oil slurry and coker gasoline enter a heat settler at a weight ratio of 10:5, the settling temperature is 90°C, and the settling time is 24 hours. After removing solid particles, the catalytic cracked oil slurry and ethylene tar (the former and the latter The weight ratio is 10:1) into the bottom of the coking fractionation tower for preheating, and at the same time separate the coker gasoline in the clarified oil; the clarified oil coming out from the bottom of the coking fractionation tower enters the heating furnace through temperature-variable operation, and the temperature range is 430 ~520°C, and then enter the coke tower for deep thermal cracking reaction. The inlet temperature of the coke tower is 460-510°C, the top pressure of the coke tower is 1.0MPa, and the coke charging time is 24 hours. The needle coke generated by the reaction is deposited in the coke tower Inside; the coked oil gas from the top of the coke tower enters the fractionation tower to separate to obtain gas, gasoline, diesel oil, and gas oil, and part of the gasoline enters the heat settler.

The test results are listed in Table 3. It can be seen from Table 3 that the viscosity of the clarified oil drops from 51.24mm ² /s before sedimentation to 7.2mm ² /s, and the ash content of the clarified oil drops from 3300ppm before sedimentation to 267ppm. The removal rate is 91.9%; the CTE of coke is 2.57×10 ^-6 /℃, which can be regarded as a qualified needle coke product.

Table 1 Comparative example 1 Comparative example 2 operating conditions heat sinking Coked Diesel Oil/FCC Oil Slurry - - temperature, ℃ - 150 time, h - twenty four delayed coking Heating furnace outlet temperature, ℃ 430～520 430～520 Coke tower top pressure, MPa 0.3 0.3 cycle ratio 0.7 0.7 Slurry/clarified oil Kinematic viscosity (100℃), mm ² /s 51.24 51.24 Ash content, ppm 3300 690 Ash removal rate, % - 79.1 Coke Ash, weight % 0.71 0.7 Volatile matter, wt% 0.9 0.8 Sulfur content, wt% 0.48 0.32 True density, g/ ^cm3 2.12 2.12 CTE, ×10 ^-6 /°C 2.71 2.63

Table 2 Example 1 Example 2 operating conditions heat sinking Coked Diesel Oil/FCC Oil Slurry 0.1 0.2 temperature, ℃ 150 90 time, h twenty four 32 delayed coking Heating furnace outlet temperature, ℃ 430～520 430～520 Coke tower top pressure, MPa 0.7 0.7 cycle ratio 0.3 0.3 clarified oil Kinematic viscosity (100℃), mm ² /s 30.18 19.30 Ash content, ppm 580 420 Ash removal rate, % 82.4 87.3 Needle focus Ash, weight % 0.11 0.08 Volatile matter, wt% 0.6 0.7 Sulfur content, wt% 0.53 0.38 True density, g/ ^cm3 2.15 2.13 CTE, ×10 ^-6 /°C 2.58 2.56

table 3 Example 3 Example 4 operating conditions heat sinking Coking diesel (gasoline) oil/catalytic cracking oil slurry 0.3 0.5 temperature, ℃ 90 90 time, h 16 12 delayed coking Heating furnace outlet temperature, ℃ 430～520 430～520 Coke tower top pressure, MPa 1.0 1.0 cycle ratio 0.10 0.15 clarified oil Kinematic viscosity (100℃), mm ² /s 12.73 7.2 Ash content, ppm 280 267 Ash removal rate, % 91.5 91.9 Needle focus Ash, weight % 0.07 0.06 Volatile matter, wt% 0.8 0.7 Sulfur content, wt% 0.28 0.36 True density, g/ ^cm3 2.14 2.18 CTE, ×10 ^-6 /°C 2.54 2.57

Claims (4)

1, a kind of burnt production method of pin that removes solid particulate in the stock oil comprises:

Catalytically cracked oil and coking distillate enter at least one hot settling vessel, described coking distillate boiling spread is 150～430 ℃, the weight ratio of this distillate and catalytically cracked oil is 0.01～0.6: 1, settling temperature is 80～200 ℃, settling time is 8～36 hours, the catalytically cracked oil that removes behind the solid particulate carries out preheating with the bottom that the burnt raw material of other optional pin enters coking fractional distillation column, isolates the coking distillate in the clarified oil simultaneously;

The clarified oil that comes out at the bottom of the coking fractional distillation column enters process furnace with the burnt raw material of other optional pin and operates through alternating temperature, the scope of alternating temperature is 430～520 ℃, enter then and carry out degree of depth heat cracking reaction in the coke drum, the temperature in of coke drum is 460～510 ℃, the coke tower top pressure is 0.1～3.0MPa, filling the burnt time is 16～40 hours, and the pin coke laydown that reaction generates is in coke drum;

The coking oil gas that comes out from the coke drum top enters the separation column separation and obtains gas, gasoline, diesel oil, gas oil, and wherein part gasoline and/or part diesel oil enter hot settling vessel.

2,, it is characterized in that the burnt raw material of described other pin is selected from vacuum residuum, long residuum, fluid catalytic cracking decant oil, heavy crude, ethylene bottom oil, lubricating oil and extracts one or more mixture among oil and the thermal cracking residue out according to the method for claim 1.

3, according to the method for claim 1, it is characterized in that when the burnt raw material of pin is single catalytically cracked oil, adopt two to four hot settling vessels, the slurry oil sedimentation in one of them hot settling vessel finishes the back as the burnt raw material use of pin, and the slurry oil sedimentation in other hot settling vessel is standby.

4, according to the method for claim 1, it is characterized in that carrying out static mixing with catalytically cracked oil after part gasoline and/or diesel oil can enter hot settling vessel separately, also can take action with the catalytically cracked oil advanced person enters hot settling vessel after attitude is mixed again.