阅读说明：本技术 一种重油催化裂化原料油乳化的工艺路线 (Process route for emulsifying heavy oil catalytic cracking raw oil ) 是由 刘和来 刘坤 王庆 唐清辉 黄中华 庄永强 景文珩 于 2020-09-08 设计创作，主要内容包括：本发明提供一种重油催化裂化原料油乳化的工艺路线,涉及油品加工技术领域。该重油催化裂化原料油乳化的工艺路线如下：在二级重油加热器前将重油催化裂化装置的原料油分成两部分:a.一部分较低温度170℃-205℃原料油进膜乳化器,膜乳化器采用孔径为20nm-200nm的陶瓷膜作为乳化介质,原料油为连续相,水为分散相,在相对较低温度下及相应的跨膜压差下将分散相压过膜孔,形成均匀的油包水乳化原料油,乳化油液滴粒径为0.5μm-8.0μm。本发明工艺路线具有运行安全、能耗低、操作方便,在相对较低的温度下进行膜乳化操作,可获得粒径分布均匀、相对稳定的符合重油催化裂化进料条件的高温乳化原料油等优点,该工艺路线可大规模应用于重油催化裂化过程的原料预处理中。(The invention provides a process route for emulsifying heavy oil catalytic cracking raw oil, and relates to the technical field of oil product processing. The process route of emulsifying the heavy oil catalytic cracking raw oil is as follows: the raw oil of the heavy oil catalytic cracking device is divided into two parts in front of a secondary heavy oil heater, wherein a part of raw oil with a lower temperature of 170-205 ℃ enters a membrane emulsifier, the membrane emulsifier adopts a ceramic membrane with the aperture of 20-200 nm as an emulsifying medium, the raw oil is a continuous phase, water is a dispersed phase, and the dispersed phase is pressed through a membrane hole at a relatively lower temperature and a corresponding transmembrane pressure difference to form uniform water-in-oil emulsified raw oil, wherein the particle size of emulsified oil droplets is 0.5-8.0 mu m. The process route has the advantages of safe operation, low energy consumption and convenient operation, membrane emulsification operation is carried out at relatively low temperature, high-temperature emulsified raw oil and the like which have uniform particle size distribution and relatively stable and meet the feeding condition of heavy oil catalytic cracking can be obtained, and the process route can be applied to raw material pretreatment in the heavy oil catalytic cracking process on a large scale.)

1. A process route for emulsifying heavy oil catalytic cracking raw oil is characterized in that: the process route of emulsifying the heavy oil catalytic cracking raw oil is as follows: the raw oil of a heavy oil catalytic cracking device is divided into two parts before a secondary heavy oil heater:

a. part of raw oil with lower temperature of 170-205 ℃ enters a membrane emulsifier, the membrane emulsifier adopts a ceramic membrane with the aperture of 20-200 nm as an emulsifying medium, the raw oil is a continuous phase, water is a dispersed phase, and the dispersed phase is pressed through a membrane hole at relatively lower temperature and corresponding transmembrane pressure difference to form uniform water-in-oil emulsion, wherein the particle size of emulsion droplets is 0.5-8.0 mu m;

b. and heating the other part of the non-emulsified raw oil by a secondary heater, and mixing the heated part of the non-emulsified raw oil with the emulsified raw oil by a mixer arranged at the position right before a riser feeding nozzle to obtain the emulsified raw oil meeting the raw oil feeding condition of the heavy oil catalytic cracking device.

2. The process route for emulsifying the catalytic cracked crude oil of heavy oil according to claim 1, characterized in that: the main operation flow is as follows:

s1, mounting a ceramic membrane assembly in an emulsifier, and checking the air tightness of the emulsifier;

s2, introducing circulating hot water or steam to preheat the system device;

s3, adjusting an emulsifier pipeline by using a three-way control valve to heat raw oil with the temperature of 170-205 ℃ by using a secondary heater, wherein the oil temperature reaches 240 ℃;

s4, preheating steam by an emulsifier, boosting the pressure to the operating pressure of a raw oil system, adjusting a three-way control valve, and gradually leading raw oil with the temperature of 170-205 ℃ to enter a tube pass of the emulsifier and then to a pipeline mixer;

s5, adding 160 ℃ water into the shell pass of the emulsifier, controlling the adding amount of the emulsified water, and observing the pressure difference change of the front membrane and the rear membrane of the emulsifier;

s6, adjusting the heating quantity of the secondary heater to ensure that the oil temperature reaches 210-230 ℃ after the outlet raw oil and the emulsified raw oil are mixed;

s7, adjusting a three-way control valve, and enabling raw oil with the total heavy oil mass of about 50% to enter an emulsifier, wherein the addition amount of emulsified water is 1% -6%, and the pressure difference between the front and the back of an emulsifier membrane is kept at 0.1-0.4 MPa;

and S8, opening a feeding valve at the inlet of a nozzle of the lifting pipe, observing the running condition of the system device, and making running records of the device.

3. The process route for emulsifying the catalytic cracked crude oil of heavy oil according to claim 1, characterized in that: the flow of the raw oil entering the ceramic membrane emulsifier is 40-60% of the total flow of the raw oil, and the flow of the raw oil can be realized by a three-way flow control valve.

4. The process route for emulsifying the catalytic cracked crude oil of heavy oil according to claim 1, characterized in that: preparing emulsified raw oil by using ceramic membrane as emulsifying medium, wherein the ceramic membrane has a pore diameter of 20-200 nm and is made of Al₂O₃、ZrO₂、TiO₂、SiO₂One or more of the above components are compounded.

5. The process route for emulsifying the catalytic cracked crude oil of heavy oil according to claim 1, characterized in that: the dispersed phase is high-temperature water subjected to precision filtration, and the temperature difference between the water and the raw oil at the inlet of the emulsifier is not more than 50 ℃.

6. The process route for emulsifying the catalytic cracked crude oil of heavy oil according to claim 1, characterized in that: controlling the membrane surface flow rate of the raw oil to be 0.2m/s-2.0 m/s; controlling the transmembrane pressure difference to be 0.10-0.40 MPa, so that the dispersed phase enters the raw oil through the membrane pores in an approximate jet flow mode.

7. The process route for emulsifying the catalytic cracked crude oil of heavy oil according to claim 1, characterized in that: the mass ratio of water to oil passing through the membrane emulsifier is controlled to be 1-6%.

8. The process route for emulsifying the catalytic cracked crude oil of heavy oil according to claim 1, characterized in that: the static pipeline mixer selects medium mixing intensity, and the pressure change gradient of the emulsified raw oil in the flow channel is moderate; the static pipeline mixer is arranged at the position right before a feeding nozzle of a heavy oil catalytic cracking riser, and the mixed high-temperature emulsified raw oil quickly reaches the nozzle of the riser, so that the high-temperature demulsification rate is reduced.

Technical Field

The invention relates to the technical field of oil product processing, in particular to a process route for emulsifying heavy oil catalytic cracking raw oil.

Background

With the decreasing of conventional petroleum resources, the degree of crude oil heaviness and deterioration is increasing, and the refining of heavy and poor heavy oil into gasoline and diesel oil is more and more urgent. However, in the process of catalytic cracking reaction of heavy oil, the reaction system in the riser is in a gas-liquid-solid phase mixed state, so that the atomization and evaporation processes before the contact of the raw oil and the catalyst particles play an important role in the whole reaction.

The emulsified heavy oil is adopted as raw oil for heavy oil catalytic cracking reaction, after the emulsified heavy oil is atomized by a nozzle, overheated small water drops in the emulsified heavy oil can be quickly vaporized when being heated and the pressure is reduced, oil drops are instantaneously exploded to generate micro explosion effect to form raw oil mist, the specific surface area of the oil drops is increased, the feeding atomization effect is improved, the contact effect of the raw oil and a catalyst is changed, and the distribution of the raw oil mist on the catalyst is more uniform. Therefore, after the emulsified feeding is adopted, the catalytic cracking reaction of the heavy oil is greatly promoted, the reaction depth, the conversion rate and the selectivity are improved, and the product distribution is improved.

The common heavy oil emulsification methods mainly include: emulsifying with a high-pressure uniform distributor, mechanically stirring and emulsifying, electric ultrasonic emulsifying and the like. However, the traditional method mainly has the defects of high energy consumption of devices, large particle size of liquid drops, poor emulsion stability, equipment complexity, high operation and maintenance cost and the like. And the traditional emulsification technology has low emulsification efficiency, particularly the feed temperature of raw oil of a heavy oil catalytic cracking device reaches 210-240 ℃, emulsion liquid drops are unstable in coalescence, vaporization, high-temperature emulsion breaking and the like, and the industrialization is difficult to realize.

Patent publication No. CN 202621042U discloses an emulsifying device for heavy oil, which pumps water, emulsifier and heavy oil to a mixing channel respectively, mixes them, and then enters an oil-cutting mixer to perform mechanical cutting emulsification. However, the method has the problems of large emulsion droplet particle size, uneven distribution, easy coalescence of emulsion, high operation energy consumption cost and the like.

Patent publication No. CN 201643995U discloses an emulsifying device for heavy oil, which adds water, emulsifier and heavy oil into a premixing tank to perform mechanical stirring type premixing, and then passes the premixed solution through an emulsifying membrane made of two parallel microporous materials in the emulsifying tank. However, the method has the problems that the emulsion droplets have large particle size, the emulsion membrane has small area and low emulsion efficiency, heavy oil easily blocks membrane pores when passing through the microporous emulsion membrane, and the like.

Patent publication No. CN 02214565.6 discloses an emulsifying device for heavy oil, which is a device for adding water, an emulsifier and heavy oil into a premixing tank to perform mechanical stirring type primary emulsification, and then further emulsifying the primary emulsion through a static mixer. However, the method also has the problems of large emulsion droplet particle size, wide particle size distribution, low water addition amount, poor emulsion stability at high temperature, easy pipeline and equipment vibration and the like.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a process route for emulsifying heavy oil catalytic cracking raw oil, and solves the problems of high emulsification cost, easy blockage of emulsion membrane pores, poor high-temperature emulsion stability and the like.

(II) technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme: a process route for emulsifying heavy oil catalytic cracking raw oil comprises the following steps: the raw oil of a heavy oil catalytic cracking device is divided into two parts before a secondary heavy oil heater:

a. part of raw oil with lower temperature of 170-205 ℃ enters a membrane emulsifier, the membrane emulsifier adopts a ceramic membrane with the aperture of 20-200 nm as an emulsifying medium, the raw oil is a continuous phase, water is a dispersed phase, and the dispersed phase is pressed through a membrane hole at relatively lower temperature and corresponding transmembrane pressure difference to form uniform water-in-oil emulsion, wherein the particle size of emulsion droplets is 0.5-8 mu m;

b. and heating the other part of the non-emulsified raw oil by a secondary heater, and mixing the heated part of the non-emulsified raw oil with the emulsified raw oil by a mixer arranged at the position right before a riser feeding nozzle to obtain the emulsified raw oil meeting the raw oil feeding condition of the heavy oil catalytic cracking device.

Preferably, the main operation flow is as follows:

s1, mounting a ceramic membrane assembly in an emulsifier, and checking the air tightness of the emulsifier;

s2, introducing circulating hot water or steam to preheat the system device;

s3, adjusting an emulsifier pipeline by adopting a three-way control valve, heating raw oil at the temperature of 170-205 ℃ by a secondary heater, and enabling the oil temperature to reach 240 ℃;

s4, boosting the pressure of the steam of the emulsifier to the operating pressure of the raw oil system, adjusting a three-way control valve, and gradually leading the raw oil with the temperature of 170-205 ℃ to enter a tube pass of the emulsifier and then to a pipeline mixer;

s5, adding 160 ℃ water into the shell pass of the emulsifier, controlling the adding amount of the emulsified water, and observing the pressure difference change of the front membrane and the rear membrane of the emulsifier;

s6, adjusting the heating quantity of the secondary heater to ensure that the oil temperature reaches 210-230 ℃ after the outlet raw oil and the emulsified raw oil are mixed;

s7, adjusting a three-way control valve, and enabling raw oil with the total heavy oil mass of about 50% to enter an emulsifier, wherein the addition amount of emulsified water is 1% -6%, and the pressure difference between the front and the back of an emulsifier membrane is kept at 0.1-0.4 MPa;

and S8, opening a feeding valve at the inlet of a nozzle of the lifting pipe, observing the running condition of the system device, and making running records of the device.

Preferably, the flow of the raw oil entering the ceramic membrane emulsifier is 40-60% of the total flow of the raw oil, and the flow of the raw oil can be realized by a three-way flow control valve.

Preferably, ceramic membrane with aperture of 20-200 nm and material including Al is used as emulsifying medium for preparing emulsified raw oil₂O₃、ZrO₂、TiO₂、SiO₂One or more of the above components are compounded.

Preferably, the dispersed phase is high-temperature water subjected to precision filtration, and the temperature difference between the water and the raw oil at the inlet of the emulsifier is not more than 50 ℃.

Preferably, the membrane surface flow rate of the raw oil is controlled to be 0.2m/s-2.0 m/s; controlling the transmembrane pressure difference to be 0.10-0.40 MPa, so that the dispersed phase enters the raw oil through the membrane pores in an approximate jet flow mode.

Preferably, the mass ratio of water to oil passing through the membrane emulsifier is controlled to be 1-6%.

Preferably, the static pipeline mixer adopts medium mixing intensity, and the pressure change gradient of the emulsified raw oil in the flow channel is moderate; the static pipeline mixer is arranged at the position right before a feeding nozzle of a heavy oil catalytic cracking riser, and the mixed high-temperature emulsified raw oil quickly reaches the nozzle of the riser, so that the high-temperature demulsification rate is reduced.

(III) advantageous effects

The invention provides a process route for emulsifying heavy oil catalytic cracking raw oil. The method has the following beneficial effects:

1. the process route of the invention adopts the raw oil with the temperature of 170-205 ℃ for emulsification, which is 35 ℃ lower than the common membrane emulsification, the fluidity of the heavy oil is still good at the temperature, the viscosity is 1cP-3cP, the membrane emulsification is not influenced, the emulsification process is ensured to be carried out at the phase transition temperature of water, the vaporization of the emulsified water is reduced, the heat loss of the raw oil is reduced, the air resistance of a membrane tube is reduced, the emulsification efficiency is improved, and the risk of thermal shock cracks generated by the ceramic membrane tube at high temperature is effectively reduced; the risk of leakage of the membrane tube seal is reduced; greatly reduces the temperature difference stress of parts such as the equipment tube plate, the flange and the like, reduces the equipment investment and improves the equipment operation safety.

2. The average temperature of the emulsion in the process pipeline is about 35 ℃ lower than that of the emulsion in the common emulsion method, the running time of the emulsion in the pipeline at high temperature is shorter, the aggregation, delamination, vaporization and high-temperature emulsion breaking rate of the emulsion are reduced, and the vibration of the raw oil pipeline is reduced.

3. The process route of the invention is combined with the advantages of low energy consumption, uniform emulsion droplet size, good emulsion stability and the like of ceramic membrane emulsion preparation, and the process route is optimized, so that emulsification is realized at a lower temperature, an emulsion at a higher temperature is obtained, and beneficial guarantee is provided for the high-efficiency and stable operation of a heavy oil catalytic cracking device.

Drawings

FIG. 1 is a schematic view of the emulsification process of heavy oil catalytic cracking raw oil according to the present invention;

FIG. 2 is a graph of the viscosity of heavy oil as a function of temperature;

FIG. 3 is a metallographic microscope photograph of emulsified base oil with different water contents;

FIG. 4 is a graph of the emulsification flux of ceramic membranes at different pressure differentials;

FIG. 5 is a microscopic comparison of the crystal phase of emulsified oil before and after heating;

FIG. 6 is a comparison of a crystal phase microscope before and after mixing of an emulsified oil at 80 ℃ and a raw oil at 130 ℃;

FIG. 7 is a broken ceramic membrane tube;

fig. 8 is a photograph of an in situ emulsified feed oil sample.

Wherein, 1, three-way flow control valve; 2. a membrane emulsifier; 3. a static pipeline mixer; 4. a nozzle for emulsifying raw oil; 5. a secondary heater.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The first embodiment is as follows:

heavy oil catalytic cracking raw oil emulsification test device. Adopts a material with the nominal aperture of 100nm,The single-channel tubular ceramic membrane is a membrane emulsification medium, the pore diameter distribution of the single-channel tubular ceramic membrane is concentrated, the minimum pore diameter is 80nm, the maximum pore diameter is 0.75 mu m, the ceramic membrane is firstly soaked in a disperse phase for 12 hours, an electric heater controls the temperature of a raw material oil phase to be 160 ℃, and the raw material oil phase is collectedAnd a circulating oil pump is used for providing membrane surface shearing force, and the membrane surface flow rate is controlled to be 1.0 m/s. The flux of the dispersed phase penetrating through the pores of the membrane is 140 L.m < -2 > h < -1 > under the pressure difference of 0.12 MPa. The water content in the raw oil in the emulsifier is controlled to be 6 percent. After being mixed with the high-temperature 240 ℃ raw oil, the emulsified raw oil with the particle size range of 0.5-8 mu m of emulsion with the emulsified water content of 3% at 200 ℃ is obtained. The metallographic micrograph of the emulsion prepared is shown in the figure, wherein the picture 3 is the water-containing 6% emulsion which is not mixed by the mixer, and the picture 4 is the water-containing 3% emulsion which is mixed by the mixer.

Comparative example 1:

in a certain emulsification pilot test, when 220 ℃ raw oil enters an emulsification membrane assembly, the ceramic membrane cracks due to the fact that the flow of the raw oil is small and the temperature is difficult to accurately control. Picture 7 photograph of ceramic film tube broken at the time of test.

Example two:

the heavy oil catalytic cracking device adopts a multi-channel tubular ceramic membrane with the nominal aperture of 100nm as a membrane emulsification medium, the temperature of raw oil before a secondary heater is 170 ℃, the feeding pressure of raw oil is 0.9MPa, the water inlet temperature of an emulsifier is 140 ℃, the water mixing proportion of the raw oil in the emulsifier is 3%, the pressure difference before and after an emulsification membrane is 0.10MPa, the surface flow rate of the emulsification membrane is 0.9m/s, the oil temperature of the raw oil after passing through the secondary heater is 245 ℃, the temperature of the emulsified raw oil after being mixed with the emulsification oil is 203 ℃, and the system runs stably after entering a riser reactor through a nozzle. The initial observation of on-site sampling shows that a large amount of uniform small air pockets overflow in the oil product, which is caused by the fact that the pressure of emulsified oil is reduced after the emulsified oil is taken out from a pipeline, and overheated small water drops are partially vaporized. Figure 8 is a photograph of a sample of the emulsified base oil on site.

Comparative example 2

Because a catalyst heat-extraction device is installed in a certain heavy oil catalytic cracking device, a main device requires that the feeding temperature of emulsified raw oil is above 230 ℃, the temperature of the raw oil actually entering an emulsifier reaches 235 ℃, emulsified water is heated and largely vaporized in the emulsifier, transmembrane pressure difference reaches above 0.35MPa, and the emulsified oil cannot be stable, and more gas is suspected to exist in an emulsified oil pipeline. The analysis is caused by the increase of the air resistance of the ceramic membrane due to the massive vaporization of the dispersed phase and the high-temperature demulsification of the emulsified raw oil.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.