JPH0426360B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to processing of petroleum heavy oil.

The present invention relates to a method for obtaining light oil and active ingredient oil from which asphaltene and heavy metals have been removed from petroleum-based heavy oil, and at the same time, discharging asphaltene and resin with a small amount of active ingredient oil.

[Problems with the Prior Art] There are many proposals for methods for processing heavy petroleum oil and separating and recovering its active components.

The use of catalysts in the treatment of heavy oil is uneconomical due to deterioration of the catalyst by heavy metals and asphaltenes, which are contained in large amounts in heavy oil. Energy use is also a cause of economic loss.

Therefore, methods using thermal decomposition reforming or solvent extraction have been proposed and implemented as methods that do not use catalysts or hydrogen.

The visbreaking method and delayed coking method are well known as thermal decomposition reforming methods.

Partly because the target product is specific, the heat treatment of the visbreaking method is too mild and only a small portion of the macromolecular components in the raw material heavy oil are decomposed and the viscosity of the raw material heavy oil decreases. This is also due to the specificity of the target product, but the heat treatment of the delayed coking method is too harsh and unnecessarily accelerates the gasification and dehydrogenation of useful low molecular weight hydrocarbons. The two are opposite extremes. From the perspective of effective use of resources and energy, it is necessary to improve processing methods for heavy petroleum oil.

[Objective of the Invention] The object of the present invention is to reduce the loss of useful components in petroleum-based heavy oil, which is composed of various components and contains a large amount of low-value components, through a highly reliable and simple process. The object of the present invention is to provide a method in which low-value components contained in large amounts are converted to high-value components while minimizing them, and harmful or worthless components are efficiently separated.

[Structure of the Invention and Functions and Effects of Each Constituent Means] This invention provides a method for selectively thermally decomposing petroleum-based heavy oil, such as atmospheric distillation residue oil and vacuum distillation residue oil, as a raw material under specific conditions. By doing so, the decomposition is limited to only the high molecular weight hydrocarbons in the feedstock that are decomposed relatively easily, and the separation and recovery of the light hydrocarbons generated during decomposition is promoted. The progress of decomposition of hydrocarbons that have become active components is minimized, the generation of unnecessary gas is avoided, and the pyrolyzed heavy oil that flows out from the bottom of the pyrolyzer is immediately subjected to highly efficient extraction and sedimentation separation treatment. This is a series of steps in which the overall product yield from the raw petroleum heavy oil is improved to the limit by recovering substantially all of the active ingredient oil contained therein.

In the process of this invention, the thermal decomposition rate in the first stage and the extraction rate in the second stage are matched to the composition of the raw petroleum-based heavy oil and are selected to be the optimal combination. It does not use raw material such as hydrogen, requires less energy, and has a much higher yield than the conventional catalytic hydrogen cracking method, delayed coking method, or direct solvent extraction method of heavy oil raw material. The product oil, ie, the reformate from pyrolysis and the reformate recovered in the extraction process, is provided, as well as a flowable residue that is easy to handle.

During the process of this invention, as an important condition for the first stage of thermal decomposition treatment, nickel, vanadium and other heavy metals in petroleum heavy oil are converted into asphaltene components by the polycondensation reaction that progresses with the decomposition reaction. Conditions are selected that are suitable for selective concentration by migration or association with asphaltene components, and conditions for preserving capacity in subsequent steps.

Next, as an important condition for the extraction and separation treatment in the second stage, the heavy metals concentrated in the asphaltene component by the above-mentioned thermal decomposition treatment are removed as the asphaltene component is extracted and removed, so that the asphaltene component is rapidly removed. Conditions are selected to ensure substantially complete extraction and separation.

These particular two-step process sequences provide active oils with high yields and extremely low contents of asphaltenes, heavy metals, and other impurities.

In the process of this invention, the effects of both the first and second stages are interrelated to improve the quality, yield, and basic unit of the active ingredient oil.

In the first stage of thermal decomposition treatment, the agglomeration association of asphaltene itself is activated, and furthermore, the combination or association of heavy metals with asphaltene components, which is greatly influenced by the progress state, is promoted, and heavy metals are concentrated in asphaltene. In order to promote
It has been found that the thermal decomposition needs to be severe enough to decompose into light hydrocarbons at temperatures below ℃.

By the way, the visbreaking method
Process), components with a boiling point of 500℃ or higher are
Only 15-30% of the amount is decomposed into light hydrocarbons with boiling points below 500°C.

In addition, in the visbreaking method, the reaction pressure is 10 to 30
Kg/cm ² , residence time is about 10 to 40 minutes, and there is no steam treatment during the thermal decomposition reaction.

On the other hand, in order to avoid unnecessary gas generation due to excessive thermal decomposition and a decrease in the yield of the active ingredient oil, the thermal decomposition during the process of this invention is carried out at a boiling point of 500℃.
65%, preferably 60% or more of the above components have a boiling point
It is kept within a range that does not decompose into light hydrocarbons at temperatures below 500℃.

The significance of this upper limit on the severity of thermal decomposition is highly related to the economy and superiority of the entire manufacturing process.

That is, when the severity of pyrolysis exceeds the above upper limit, large amounts of low-value gases are generated and, at the same time, coke production increases significantly, causing coke in the process stream after pyrolysis and in the manufacturing process. The final discharged product, that is, asphaltene, is not a liquid but a fixed coke, which significantly complicates separation, recovery, transportation, and all other processing conditions and complicates the equipment.

Since the pyrolysis, which is the first step in the process of this invention, suppresses the production of coke and stops the pyrolysis residue from forming liquid pitch, the residue of the process of this invention is a fluid. Therefore, the processing conditions are much simpler, and the configuration of the apparatus is simplified.

In order to maintain the asphaltene-containing pitch, which constitutes the effluent stream of the first stage pyrolysis of the process of this invention, in a highly fluid liquid state, to enable highly efficient extraction and separation, the second stage solvent is The fractionation equipment used is that its extraction temperature is rich in asphaltenic oil.
The temperature is maintained at a high temperature above the softening point measured by the ball method, and the temperature and pressure are near the critical point of the solvent.

The density of asphaltenes to be extracted and separated is
Within the range of 1.2-1.5g/cc, that of Pituchi is 1.1-
Within the range of 1.2 g/cc, that of the active ingredient oil obtained by separating asphaltene from pitch is within the range of 0.95 to 1.1 g/cc.

The density of the solvent in the high temperature fractionator near the critical point is
The viscosity is within the range of 0.1 to 0.3 g/cc, and its viscosity is extremely low, close to that of gas.

Therefore, in the fractionator of the second stage, the asphaltene-containing pits, which are maintained in liquid form in the pyrolysis effluent directly introduced from the first stage, remain in a state of high fluidity. , which is also thoroughly mixed and in intimate contact with the solvent, which is also in an extremely fluid state, and undergoes a rapid extraction process.

As mentioned above, the density of the high-temperature solvent in the supercritical state is significantly lower than that of asphaltene, so asphaltene rapidly and completely settles out of the mixture of active ingredient oil and solvent and is separated. Ru.

This rapid and complete separation by sedimentation greatly contributes to the economics of this extraction process, or of the process of this invention.

Next, the mixture of active ingredient oil and solvent after asphaltene has been separated by precipitation in the extraction process is heated, and the temperature rises to a supercritical state, which further reduces the solubility of the solvent, and the active ingredient oil Similar to the settling of droplets suspended in a gas, they settle rapidly and are completely separated from the solvent.

This state eliminates the need for a huge amount of heat for evaporation, which is normally required when recovering the solvent for reuse, which is one of the reasons why the method of the present invention is extremely economical. It is one.

The advantage of the large amount of active ingredient oil produced by the first stage of thermal decomposition is ensured by the highly efficient and complete extraction and separation of the second stage.

[Description with Drawings] Hereinafter, the steps of the present invention will be explained with reference to the drawings.

FIG. 1 is a flow sheet showing the steps of this invention.

Petroleum-based heavy oil used as a raw material, such as vacuum distillation residue oil or atmospheric distillation residue oil, is introduced into a preheater 2 through a pipe 1.

In order to prevent coking inside the pipe, this preheater uses low pressure inside the pipe, approximately 1 to 10 kg/ ^cm2 , high flow rate,
It is said to be about 2 to 20 m/sec.

The process stream, which has passed through the preheater 2 and has been preheated to a temperature within the range of 450 to 500°C, is introduced through a pipe 3 into the upper part of a vertical cylindrical pyrolyzer 4.

The pyrolyzer 4 has a structure as simple as possible in pursuit of reliability and economy.

In order to reach the required decomposition rate, the residence time in the pyrolyzer is at least twice as long as that in the visbreaking method.

The inside of the pyrolyzer is maintained at normal pressure, and heated steam is supplied to the bottom to promote ejection of high-boiling components in the active ingredient oil, eliminating the need for a vacuum distillation process for the outflow from the bottom of the pyrolyzer. Ru.

Within the pyrolyzer, the process stream is lowered and
Although it is discharged from the bottom of the pyrolyzer, several stages of horizontal porous partition plates are installed inside the pyrolyzer to prevent short circuits, drift, backflow, and vortices while descending in the pyrolyzer. ing.

A mixture of gaseous products produced by the pyrolysis reaction and ejection steam rises countercurrently to the descending process stream and is discharged from the top of the pyrolyzer.

In the pyrolyzer, in order to prevent the process flow from stagnation and coke formation near the inner wall surface or the surface of the horizontal porous partition plate, a horizontal rotary stirring type that operates at low speed along these surfaces is used. The machine is equipped.

The pyrolyzer 4 uses these internal equipment to ensure plug flow-like flow of the process stream in the pyrolyzer, and prevents coke precursors (meso-phase) generated as the pyrolysis reaction progresses in the descending process stream. ) is mixed with a process stream whose thermal decomposition is still insufficient, which contains a large amount of light hydrocarbon components with low affinity for coke precursors, and is dispersed as fine particles as possible in the process stream without precipitation and agglomeration. It exists in a dispersed manner and is discharged from the bottom of the pyrolyzer 4 without being coked. In the pyrolyzer 4, light hydrocarbon vapors and a small amount of gas produced by pyrolysis flow counter-currently to the descending process stream, pass through the perforated holes in the perforated plate, rise, and rise at the top of the pyrolyzer 4. It was separated from the process stream and discharged, led to a concentrator 20 by a pipe 19, and then in a separation tank 21, the gaseous mixture was separated in the upper part, and the condensed water was separated from the condensed oil by density difference. Thereafter, it is discharged from the lower part of the separation tank 21 through a pipe 23, and the condensed active ingredient oil is discharged through a pipe 34 and recovered. If light hydrocarbons produced by thermal decomposition remain in the process stream, they will promote coke precipitation and coke formation due to their low affinity with the coke precursor as described above. In order to prevent high-boiling fractions in hydrogen from remaining dissolved in the process stream, water vapor for ejecting these fractions is introduced into the process stream in the lower part of the pyrolyzer 4 through a pipe 18. Supplied.

If light hydrocarbons are mixed into the solvent in a directly connected second-stage solvent-using separation device and the amount increases, the selectivity of the solvent will gradually decrease, reducing the capacity of the separation device and reducing the amount of solvent replenishment. For this purpose, sufficient evacuation of light hydrocarbons in the pyrolyzer 4 is extremely important.

Therefore, the amount of ejection steam used is within the range of 5 to 20 wt% based on the amount of active ingredient oil in the product.

The decomposition reaction is an endothermic reaction, and the pyrolyzer 4 is of an adiabatic type, so the temperature of the process flow decreases as it descends through the pyrolyzer. However, in order to maintain a predetermined decomposition rate, The lower limit is set to at least 400℃.

Since the light hydrocarbons produced by pyrolysis have already been removed by steam ejection, the amount discharged from the bottom of the pyrolyzer 4 is pressurized by the pump 5 and passed through the pipe 6 without going through the distillation process. , directly into the solvent mixer 7 of the solvent-based fractionation device.

In the mixer 7, the process stream mixed with the solvent is introduced via a pipe 8 into the middle section of the first stage separation column 9 of the fractionator.

The mixing ratio (volume ratio) of process flow and solvent is 1:
It is said to be about 8 to 1:12.

In the separation column 9 near the critical state of high temperature and high pressure, the process stream thoroughly mixed with the solvent becomes a process stream that is a light phase of a fluid mixture consisting of active ingredient oil, resinous substances, and solvent, and asphaltene. The heavy phase, which is in a fluid state and consists of a small amount of solvent and a small amount of solvent, settles and is separated from the light phase of the process stream.

The process stream, which is a light phase, flows from the top of the separation column 9 to pipe 1.
After being discharged by the heating device 27 and heated by the heating device 27, it is introduced into the middle stage of the second stage separation column 11. A heavy phase consisting of asphaltene and a small amount of solvent is discharged from the bottom of the separation column 9 in a fluid state through a pipe 12, and is reduced to normal pressure by a valve 35 and introduced into a separator 24, where a small amount of mixed solvent is removed. is evaporated and recovered, and asphaltenes are collected in tube 25.
is discharged and collected.

In the separation column 11, the process stream becomes a light phase of a mixture in a fluid state consisting of active ingredient oil and a solvent, and a heavy phase in a fluid state consisting of a resinous material and a small amount of solvent is a light phase. From the process flow,
Separated downward.

A process stream, which is a light phase, is discharged from the top of the separation column 11 through a pipe 13, heated by a heating device 28, and then introduced into the middle section of the third stage separation column 14.

A heavy phase resinous substance is detected in a fluid state from the bottom of the separation column 11 through a pipe 15 and recovered.

In the separation column 14 in a supercritical state, the process stream that has become a product, deasphaltenized oil, collects at the bottom of the separation column 14 to form a heavy phase, while
The solvent separated by precipitation of the deasphaltenized oil forms a light phase in the upper part of the separation column 14. The product, deasphaltenized oil, is sent to a separation column 14 via a pipe 16.
is discharged from the bottom and collected.

The solvent forming the light phase from the top of the separation column 14 is discharged via line 17 via a cooler 29 and pump 31, and some of the solvent recovered from the upper part of the separator 24 is removed via line 26. Condenser 3
0, at which point it becomes liquid and the pump 32
is returned to the mixer 7.

New solvent is supplied by a pump 36 and a pipe 37 in order to replenish the amount of solvent that is lost due to trace amounts entrained in asphaltene and active ingredient oil and left out of the system.

[Example and Comparative Example] Example 83ppm of nickel and vanadium
Feedstock oil, which is vacuum distillation residue oil of Middle Eastern crude oil containing 272 ppm, is preheated to 480℃ and supplied to a pyrolysis machine that has 10 horizontal perforated plates for rectification inside, and the pyrolysis machine leaks under normal pressure. Temperature 420℃, residence time
For 120 minutes, steam flows from the bottom of the pyrolyzer into the raw oil.
The fraction with a boiling point of 500℃ or higher in the feedstock is thermally decomposed under the reaction conditions and is fed at a ratio of 10wt%.
55wt% was converted to fractions with boiling points below 500°C.

The composition of the effluent from the pyrolysis machine is 4wt% gaseous decomposition products and pyrolysis light oil based on the weight of the feedstock oil.
It was 51wt%.

This cracked heavy oil had a softening point temperature of 150°C as measured by the ring-ball method, and an asphaltene content of 40 wt%.

The pyrolyzed heavy oil was fed into the mixer from the bottom of the pyrolyzer, mixed with 10 times the amount of cyclohexane, and then introduced into the first stage separation column.

The temperature and pressure inside the first separation column were maintained at 282°C and 52atm.

The asphaltene-containing flow with a solvent cyclohexane content of 30% is discharged from the lower part of the first stage separation tower, and the pressure is reduced to normal pressure, and 98% of the solvent cyclohexane is evaporated by flashing, separated and recovered, and the pyrolyzed heavy It was recovered as asphaltene-rich oil in an amount of 45 wt% based on oil.

This rich asphaltene oil contains nickel
It contained 460ppm vanadium and 1500ppm, and the softening point temperature was 240°C by ring-ball method.

The mixture of active ingredient oil and solvent was discharged from the upper part of the first stage separation column and heated, and then introduced into the second separation column whose internal temperature and pressure were 290°C and 50 atm.

For pyrolysis heavy oil from the bottom of the second separation tower
A 10wt% amount of resin oil was discharged and recovered.

After the process stream discharged from the upper part of the second stage separation column is heated, the internal temperature and pressure are 316℃
It was introduced into a 46 atm third stage separation column.

In the third stage separation column, the active ingredient oil and the solvent are separated, the active ingredient oil is discharged from the bottom of the column and collected, and the solvent is discharged from the upper part and after being cooled, is returned to the mixer for reuse. Ta.

The active ingredient oil collected by the third stage separation tower is
The yield was 45 wt% based on pyrolysis heavy oil, asphaltene content was less than 0.5 wt%, nickel content was 10 ppm, and vanadium content was 20 ppm.

The total yield of the pyrolyzed light oil directly recovered from the pyrolyzer and the active ingredient oil extracted and separated using a solvent was 71.25 wt%, and the removal rate of heavy metals from the feedstock oil was 98.3%. Ta.

The consumption amount of the solvent cyclohexane was 0.2 wt% based on the raw oil.

Comparative example The same raw material oil as in the example was preheated to 450°C,
The oil is supplied to the same pyrolyzer and is thermally decomposed under normal pressure and residence time at 400°C for 20 minutes, converting 30wt% of the fraction with a boiling point of 500°C or higher in the raw oil to a fraction with a boiling point of 500°C or lower. I was made to do it.

No steam was supplied to the bottom of the pyrolyzer.

The pyrolyzed heavy oil discharged from the bottom of the pyrolyzer is
It was mixed with 10 times the amount of pentane and sent to the first stage separation column, where the internal temperature and pressure were 177°C and 42 atm.

The asphaltene-containing stream containing pentane is discharged from the lower part of the first separation column, and the pressure is reduced to normal pressure, and the solvent pentane is evaporated by flashing and separated and recovered. Rich asphaltene oil was recovered.

This rich asphaltene oil contains nickel
Contains 276ppm vanadium 740ppm, ring
The softening point temperature measured by the ball method was 120°C.

The mixture of active ingredient oil and solvent was discharged from the upper part of the first-stage separation column and heated, and then introduced into the second-stage separation column at an internal temperature and pressure of 200°C and 46 atm.

For pyrolysis heavy oil from the bottom of the second stage separation tower
Resin oil in the amount of 10wt% was discharged and recovered.

The process stream discharged from the upper part of the second stage separation column is heated, and then the internal temperature and pressure are 227℃.
It was introduced into a 44 atm third stage separation column.

In the third stage separation column, the active component oil and the solvent are separated, the molten component oil is discharged from the bottom of the column and collected, and the solvent is discharged from the top and after being cooled, it is returned to the mixer for reuse. Ta.

The active ingredient oil recovered by the third separation tower has a yield of 55wt% based on pyrolysis heavy oil, has an asphaltene content of 0.1wt% or less, and a nickel content.
The vanadium content was 40ppm, and the vanadium content was 100ppm.

The total yield of the pyrolyzed light oil directly recovered from the pyrolyzer and the active ingredient oil extracted and separated using a solvent was 65.55 wt%, which was a lower yield than that of the example. Regardless, the removal rate of heavy metals from the raw oil remained at 85%. Note that the consumption amount of the solvent penta was 1.0 wt% based on the raw oil.

[Brief explanation of drawings]

FIG. 1 is a flow sheet outlining the steps in which the method of the invention is carried out. Partial symbol list, 1...Pipe (raw oil supply), 2
... Preheater, 4 ... Pyrolyzer, 5 ... Pump, 7
... Mixer, 9 ... Separation column (first stage), 11 ...
Separation column (second stage), 12... pipe (solvent-containing asphaltene discharge), 14... separation column (third stage), 15
...Pipe (resin material discharge), 16 ... pipe (active ingredient oil discharge), 17 ... pipe (solvent return), 18 ... pipe (ejected steam supply), 19 ... pipe (in pyrolysis machine) 20...Condenser, 21...Separator (gas/oil/water), 22...Pipe (gas discharge), 23
...Pipe (water discharge), 24 ...Separation tower (solvent recovery),
25... pipe (asphaltene discharge), 26... pipe (recovery solvent), 27... heater, 28... heater,
29...Cooler, 30...Condenser, 33...Pipe (solvent return), 34...Pipe (pyrolysis product oil discharge),
35... pressure reducing valve, 37... pipe (solvent supply).

Claims (1)

[Claims] 1 Petroleum-based heavy oil is heated to a temperature within the range of 450 to 500°C by a preheater, and then introduced into the upper part of the thermal decomposer which is in an adiabatic state, and the temperature range is Under the reaction conditions of 400 to 450℃, normal pressure, and residence time of 1 to 5 hours, Plug-Flow occurs in the pyrolyzer while undergoing rectification by a multi-stage horizontal perforated plate and low-speed horizontal stirring by a stirrer. The gaseous products of the pyrolysis reaction rise countercurrently to the descending liquid flow together with the driving steam introduced into the lower part of the pyrolyzer and are separated. , 35 to 65% of the components with a boiling point of 500°C or higher in the raw petroleum heavy oil are converted to components with a boiling point of 500°C or lower, and the discharge stream from the bottom of the pyrolyzer immediately has an internal temperature of 500°C or higher. It is characterized by being introduced into a fractionation device using a solvent that is maintained at a temperature higher than the softening point temperature of asphaltene oil in a supercritical state according to the ring-and-ball method of measuring asphaltene oil, and is then treated and separated into active ingredient oil and asphaltene oil. A method for producing pyrolyzed reformed oil.