CN109705916B

CN109705916B - Process for processing residua feedstocks

Info

Publication number: CN109705916B
Application number: CN201711012670.5A
Authority: CN
Inventors: 施瑢; 邵志才; 邓中活; 胡大为; 戴立顺; 聂红; 杨清河; 刘涛; 孙淑玲; 聂鑫鹏; 任亮; 赵宁
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2017-10-26
Filing date: 2017-10-26
Publication date: 2021-03-12
Anticipated expiration: 2037-10-26
Also published as: CN109705916A

Abstract

The invention relates to the field of residual oil hydrogenation, and discloses a method for processing a residual oil raw material, which comprises the following steps: introducing a first material containing raw material residual oil into a fixed bed hydrogenation device which sequentially comprises a protection reaction zone, a hydrodemetallization reaction zone and a desulfurization and carbon residue removal reaction zone which are connected in series for hydrogenation reaction, cutting out any one of a reactor A and a reactor B after the fixed bed hydrogenation device runs for a period of time, and introducing a second material containing hydrogen and cleaning oil into the cut-out reactor for hydrogenation cleaning treatment; and switching the material from the upstream of the reactor A to be introduced into the uncut reactor of the reactor A and the reactor B together with the reaction effluent from the cut-out reactor for hydrogenation reaction and then discharged from the device. The method can eliminate the carbon deposit on the catalyst of the desulfurization and carbon residue removal reactor on line, thereby prolonging the operation period.

Description

Process for processing residua feedstocks

Technical Field

The invention relates to the field of residual oil hydrogenation, in particular to a method for processing a residual oil raw material.

Background

Along with the increasing weight change of crude oil, the variety of crude oil is increasing, and the requirement on the weight change of heavy oil products is also increasing.

"heavy oil" refers to hydrocarbons of high asphaltene content derived from topped crude oil, petroleum residuum, oil sands, bitumen, shale oil, liquefied coal, or reclaimed oil.

The hydrogenation process of heavy oil is a heavy oil deep processing technology, and is characterized by that in the presence of hydrogen gas and catalyst the heavy oils of residual oil, etc. are undergone the processes of hydrodesulfurization, hydrodenitrogenation, hydrodemetallization, residual carbon conversion and hydrocracking reaction, so that the obtained hydrogenated residual oil can be used as feed material for high-quality catalytic cracking to produce light oil product so as to attain the goal of maximally lightening residual oil and implement non-residual oil refinery.

To date, four process types have been developed for residuum hydrogenation: fixed beds, ebullated beds, slurry beds, and moving beds. Among the four process types, the fixed bed process is mature and easy to operate, and the equipment investment is relatively low; the product hydrogen content is increased more and the unconverted residue can be used as RFCC feed, which is the most industrially applicable of the four processes.

In the prior art, generally, a plurality of hydrogenation reactors are arranged to realize the hydrogenation treatment of heavy oil products.

The deactivation of the catalyst for hydrotreating residual oil is mainly due to two reasons: the metal deposition and the carbon deposition of the catalyst are deactivated. The deposition of sulfides of metals Ni and V can cause deactivation of the residuum hydrogenation catalyst when processing the residuum feedstock. Meanwhile, the same as the deactivation of the distillate oil hydrogenation catalyst, the carbon deposit on the catalyst is also an important factor for the deactivation of the catalyst. Polycyclic aromatic hydrocarbon substances including colloids and asphaltenes in the residual oil raw material are adsorbed on the surface of the catalyst and then condensed and coked to form carbon deposit, so that the catalyst is inactivated. Therefore, when processing residual oil raw materials with high asphaltene and colloid contents, carbon deposition on the catalyst is an important reason for catalyst deactivation.

In the residual oil hydrogenation process, in order to inhibit the precipitation of asphaltene on a catalyst and carbon deposition, high-aromaticity raw materials are mostly adopted in the prior art, and the precipitation of asphaltene in a residual oil raw material is inhibited by utilizing the physical principle of similarity and intermiscibility.

CN1484684A discloses a process for hydroprocessing heavy hydrocarbon fractions using a replaceable reactor and a short-circuiting reactor, which process regenerates or replaces the catalyst after the reactor has been blocked or the catalyst therein has been deactivated. With this process the catalyst needs to be replaced or the reactor regenerated requiring a shutdown and a series of corresponding equipment to re-sulfurize the regenerated or replaced catalyst.

CN102876373A discloses a method for prolonging the operation period of a hydrotreatment device, in the steady-state deactivation stage of a hydrotreatment catalyst, the method cools a reactor, switches raw oil into cleaning oil, maintains a lower hydrogen-oil ratio, and flushes a catalyst bed layer with the maximum oil inlet amount; raising the temperature of a catalyst bed layer, injecting a certain proportion of scale inhibitor into the cleaning oil, and performing circulation operation until no solid coke particles exist in the oil generated at the bottom of the fractionating tower; and adjusting the temperature, and injecting a vulcanizing agent into the cleaning oil to carry out supplementary vulcanization on the catalyst, thereby improving the activity of the catalyst. The method mainly uses physical decoking to dissolve soft coke and polymers adsorbed on the catalyst, and the device needs to be cooled, and has longer time for cleaning and sulfur supplement, so that the device can not carry out normal production.

CN102816598A discloses a method for reducing carbon deposition of a carbon residue removing catalyst of a residual oil hydrotreater, which is characterized in that a feed inlet is added in front of a carbon residue removing agent bed layer of the residual oil hydrotreater, high-aromaticity catalytic cracking recycle oil with 1-30% of the weight of raw residual oil is introduced through the feed inlet, and the dissolving capacity of asphaltene gradually separated out from the raw oil is increased, so that the carbon deposition on the catalyst is reduced.

CN102816595A A combined process of hydrotreatment and catalytic cracking of catalytic cracking recycle oil on residual oil, which is characterized in that a feed inlet is respectively added before a demetallization bed layer, a desulfurizer bed layer and a carbon residue removing agent bed layer of a device, the recycle oil is introduced into one or more feed inlets, and the carbon deposition speed of a catalyst is delayed. However, the method mixes the recycle oil into the residual oil raw material and the reactant thereof, and residual oil hydrogenation inevitably generates carbon deposit, so that the carbon deposit effect on the catalyst of the elimination protection reactor is not obvious.

CN101037618A discloses a coking inhibitor, a preparation method and an application thereof, wherein the coking inhibitor is a hydro-upgrading product of one or more hydrocarbon mixtures selected from coal tar, ethylene tar, catalytic cracking cycle oil, catalytic cracking slurry oil, catalytic cracking heavy oil, catalytic cracking extract oil and coking wax oil, and is used for preventing, delaying and eliminating coking in relevant equipment and pipelines in petroleum refining and petrochemical processes. The inhibitor needs to be added into the working fluid, and has limited effect on eliminating carbon deposit.

Disclosure of Invention

The invention aims to overcome the defects of the existing method for eliminating or inhibiting carbon deposit, and provides a method for eliminating carbon deposit on a catalyst of a desulfurization and carbon residue removal reactor on line, thereby prolonging the operation period and realizing easy agent unloading and processing of poor-quality residual oil raw materials.

The research of the inventor of the invention finds that when oil with high aromaticity is introduced into a hydrogenation device together with residual oil raw materials under the pressure of residual oil hydrogenation reaction, although the method can dissolve asphaltene to remove the asphaltene, the method has a poor cleaning effect on carbon deposit on the catalyst in the hydrogenation device with serious carbon deposit; however, the inventor of the present invention found in the research that when a highly aromatic oil product is fed alone (without the residual oil feedstock) and hydrogen gas are fed into a reactor containing a residual oil hydrogenation old catalyst for hydrogenation, the hard carbon on the old catalyst undergoes hydrogenation reaction, and due to the large molecular structure of the hard carbon, activated hydrogen cannot be directly obtained from the active center of the catalyst due to steric hindrance effect, but the hydrogen donor compound in the highly aromatic oil product can provide or transfer the activated hydrogen to the hard carbon in the absence of the residual oil feedstock, so as to promote the conversion of the hard carbon into soft carbon, and the soft carbon can be dissolved in the highly aromatic oil product and converted into the oil product through hydrogenation reaction. Based on this finding, the inventors have completed the technical solution of the present invention.

In order to achieve the above object, the present invention provides a method of processing a residual oil feedstock, the method comprising: under the condition of hydrotreatment, introducing a first material containing raw material residual oil into a fixed bed hydrogenation device sequentially comprising a protection reaction zone, a hydrodemetallization reaction zone and a desulfurization and decarburization reaction zone which are connected in series for hydrogenation reaction, wherein the desulfurization and decarburization reaction zone at least comprises two reactors which are sequentially connected in series and are respectively a reactor A and a reactor B, and the material from the upstream of the reactor A sequentially enters the reactor A and the reactor B for hydrogenation reaction and then is discharged out of the device;

(a) cutting out any one of the reactor A and the reactor B when the fixed bed hydrogenation apparatus reaches any one of the following conditions, and introducing a second material containing hydrogen and a cleaning oil into the cut-out reactor to perform a hydrocleaning treatment therein; and switching the material from the upstream of the reactor A to be introduced into the unswitched reactor of the reactor A and the reactor B together with the reaction effluent from the switched-out reactor for hydrogenation reaction and then discharged out of the device;

the conditions to be achieved by the fixed bed hydrogenation unit comprise any one of the following conditions:

(1) the fixed bed hydrogenation device continuously operates for more than 15 days;

(2) the pressure drop in the reactor a or the reactor B reaches an upper pressure drop limit;

(3) hot spots appear on the catalyst in the reactor A or the reactor B, so that the radial temperature difference of the reactor is more than or equal to 5 ℃;

optionally, repeating said step (a) by alternating said hydrogenation reaction and said hydroprocessmg treatment of said reactor a and said reactor B until said fixed bed hydrogenation unit reaches a shutdown condition;

wherein the total aromatic hydrocarbon content in the cleaning oil is 50-95 wt%.

The method for processing the residual oil raw material can obviously eliminate carbon deposit on the catalyst of the desulfurization and carbon residue removal reactor on line, thereby prolonging the operation period and realizing easy agent unloading.

Drawings

FIG. 1 is a process flow diagram for processing a residuum feedstock in accordance with a preferred embodiment of the present invention.

Description of the reference numerals

1. Protection of the reaction zone

2. Demetallization reaction zone

3. Reactor A

4. Reactor B

5. First material

6. The second material

7. Third material

8. First reactor of desulfurization and carbon residue removal reaction zone

01. 02, 03, 04, 05 and 06 are valves.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

As previously mentioned, a first aspect of the present invention provides a process for processing a residuum feedstock, the process comprising: under the condition of hydrotreatment, introducing a first material containing raw material residual oil into a fixed bed hydrogenation device sequentially comprising a protection reaction zone, a hydrodemetallization reaction zone and a desulfurization and decarburization reaction zone which are connected in series for hydrogenation reaction, wherein the desulfurization and decarburization reaction zone at least comprises two reactors which are sequentially connected in series and are respectively a reactor A and a reactor B, and the material from the upstream of the reactor A sequentially enters the reactor A and the reactor B for hydrogenation reaction and then is discharged out of the device;

In the present invention, according to a preferred embodiment, with the aforementioned process for processing a residual oil feedstock provided by the present invention, when repeating said step (a) until the fixed bed hydrogenation unit reaches a shutdown condition, the process of the present invention has the advantage of being able to significantly extend the continuous operating cycle of the fixed bed hydrogenation unit.

Preferably, in the step (a), when the pressure drop in the cut-out reactor and the radial temperature difference in the reactor are recovered to within preset values during the hydro-cleaning treatment of the cut-out reactor, the introduction of the second material into the cut-out reactor is stopped, and the reaction effluent in the uncut reactor is introduced into the cut-out reactor to be subjected to the hydrogenation reaction and then discharged from the device.

For step (a) of the present invention, the present invention provides several preferred embodiments as follows:

according to a first preferred embodiment, in step (a), when the reactor a is cut out and subjected to a hydro-cleaning treatment, when the pressure drop in the reactor a and the radial temperature difference in the reactor return to within preset values, the introduction of the second material into the reactor a is stopped, the cleaning oil in the second material is switched back to the first material, and the reaction effluent in the reactor B is introduced into the reactor a and discharged from the device after the hydrogenation reaction.

According to a second preferred embodiment, in step (a), when the reactor B is cut out and subjected to a hydro-cleaning treatment, when the pressure drop in the reactor B and the radial temperature difference in the reactor return to within preset values, the introduction of the third material into the reactor B is stopped, the cleaning oil in the third material is switched back to the first material, and the reaction effluent in the reactor a is introduced into the reactor B for a hydrogenation reaction and then discharged from the device.

According to a third preferred embodiment, in the step (a), when the reactor A is cut out and subjected to the hydro-cleaning treatment, when the pressure drop in the reactor A and the radial temperature difference in the reactor are recovered to be within preset values, the introduction of the second material into the reactor A is stopped, the cleaning oil in the second material is switched back to the first material, and the reaction effluent in the reactor B is introduced into the reactor A and is discharged out of the device after the hydrogenation reaction; and

in the step (a), cutting out the reactor B, and carrying out hydrogenation cleaning treatment on the reactor B, when the pressure drop in the reactor B and the radial temperature difference in the reactor are recovered to be within preset value ranges, stopping introducing the third material into the reactor B, switching the cleaning oil in the third material back to the first material, and introducing the reaction effluent in the reactor A into the reactor B for hydrogenation reaction and then discharging the reaction effluent out of the device.

Preferably, the conditions of the reactor a or the reactor B are controlled so that the reactor a or the reactor B is in a state where the hydrotreating has been performed for at least 24 hours when the fixed-bed hydrogenation apparatus is stopped on line.

In the present invention, according to another preferred embodiment, further, with the method for processing a residual oil feedstock provided by the present invention, when the conditions of the reactor a or the reactor B are controlled so that the reactor a or the reactor B is in a state of performing the hydrotreating for at least 24 hours while the fixed bed hydrogenation apparatus is in an on-line shutdown state, the cleaning oil introduced therein can be subjected to a decarburization reaction with accumulated carbon on the catalyst therein, thereby making it easier to unload the catalyst in the desulfurization and decarburization reaction zone.

More preferably, in the present invention, the conditions of the reactor a or the reactor B are optionally controlled so that the pressure drop to which the reactor a or the reactor B is purged and the radial temperature difference in the reactor are restored to a state within a preset value range when the fixed bed hydrogenation apparatus is shut down on line. Thus, the catalyst in the desulfurization and carbon residue removal reaction zone in the method is more beneficial to being easily unloaded.

The restoration of the radial temperature difference to the preset value within the preset value range according to the present invention can be confirmed by those skilled in the art according to the working condition, and there is no particular limitation thereto.

It should be noted that, in the foregoing process provided by the present invention, when the fixed bed hydrogenation apparatus is formally stopped, the reactor a and the reactor B may undergo three state transitions, where the first state transition is a transition from the hydrogenation reaction state to the shutdown state; the second state is changed into the reactor A from the hydrogenation reaction state to the shutdown state, and the reactor B is changed from the hydrogenation cleaning treatment state to the shutdown state; the third state is changed into the reactor B from the hydrogenation reaction state to the shutdown state, and the reactor A is changed from the hydrogenation cleaning treatment state to the shutdown state. Moreover, the first state transition is beneficial to prolonging the operation period of the fixed bed hydrogenation device; and the second state transition and the third state transition make the unloading of the catalyst in the desulfurization and carbon residue removal reaction zone easier.

Thus, the process for processing a residuum feedstock provided by the present invention has the advantage of high flexibility.

Preferably, in the process of the invention, the cut-out reactor a or reactor B is shut down on-line with the other reactors in the fixed bed hydrogenation unit normally processed for production.

Preferably, the total aromatic hydrocarbon content in the cleaning oil is 80-90 wt%.

Preferably, the content of the bicyclic aromatic hydrocarbon in the cleaning oil is 30-80 wt%; more preferably 50 to 70 wt%.

Preferably, the cleaning oil is at least one selected from straight-run diesel oil, catalytic cracking cycle oil and catalytic cracking slurry oil, and more preferably the catalytic cracking slurry oil of the invention is catalytic cracking slurry oil with solid particles removed.

The catalytic cracking diesel oil can be used for diesel oil of various catalytic cracking processes, such as DCC, MIP, HSCC and the like.

The aforementioned second and third materials of the present invention may be identical, or different cleaning oils may be selected to form the second and third materials within the scope of the alternative cleaning oils provided by the present invention.

Preferably, the upper limit of the pressure drop is 40-80% of the maximum design pressure drop of the corresponding reactor in the desulfurization and carbon residue removal reaction zone; more preferably, the upper limit of the pressure drop is 45-75% of the maximum design pressure drop of the corresponding reactor in the desulfurization and carbon residue removal reaction zone.

Preferably, the radial temperature difference reaches 15-40 ℃; more preferably, the radial temperature difference reaches 20 ℃ to 35 ℃.

Preferably, in order to further extend the operation period of the apparatus, in the step (a), the continuous operation time of the hydrogenation reaction before the reactor a and the reactor B are cut out each time to be subjected to the hydrogenation cleaning treatment is 1/8 to 1/2, more preferably 1/4 to 1/3 of the continuous operation period of the fixed bed hydrogenation apparatus.

Preferably, in order to further extend the operation period of the apparatus, in the step (a), the time for which the reactor a and the reactor B are cut out each time to be subjected to the hydrocleaning treatment is 1/16 to 1/4, more preferably 1/8 to 1/6, of the continuous operation period of the fixed bed hydrogenation apparatus.

Preferably, the weight ratio of the raw residue in the first material to the cleaning oil in step (a) is 10: (1-4.5).

Preferably, the first material further contains a cleaning oil, and in the step (a), the cleaning oil in the first material is cut out and introduced into the cut-out reactor for a hydro-cleaning treatment. More preferably, in step (a), when the pressure drop in the cut-out reactor and the radial temperature difference in the reactor are restored within preset values during the hydro-cleaning treatment of the cut-out reactor, the introduction of the second material into the cut-out reactor is stopped, the cleaning oil in the second material is switched back to the first material, and the reaction effluent in the uncut reactor is introduced into the cut-out reactor for the hydrogenation reaction and then discharged from the device.

Preferably, residual oil hydrogenation process conditions are adopted in a fixed bed hydrogenation device before and after the reactor A or the reactor B is cut out from the desulfurization and carbon residue removal reaction zone, and the residual oil hydrogenation process conditions comprise: the hydrogen partial pressure is 5.0-22.0 MPa, the reaction temperature is 330-450 ℃, and the volume space velocity is 0.1-3.0 h^-1The volume ratio of hydrogen to oil is 350-2000.

Preferably, the cut-out conditions of the hydro-cleaning treatment in the reactor A or the reactor B in the desulfurization and carbon residue removal reaction zone comprise: the hydrogen partial pressure is 5.0-22.0 MPa, the reaction temperature is 300-400 ℃, the hydrogen-oil volume ratio is 50-300, and the volume space velocity is 1.0-3.0 times of the volume space velocity of the hydrogenation reaction.

Preferably, in the fixed bed hydrogenation apparatus of the present invention, the desulfurization and carbon residue removal reaction zone comprises at least two fixed bed reactors connected in series, and the protection reaction zone and the demetallization reaction zone each comprise at least one fixed bed reactor. More preferably, in the fixed bed hydrogenation apparatus of the present invention, the desulfurization and carbon residue removal reaction zone comprises at least three fixed bed reactors connected in series, and the protection reaction zone and the demetallization reaction zone each comprise at least one fixed bed reactor.

According to a preferred embodiment, the conditions of the hydrogenation cleaning treatment in the reactor A or the reactor B in the cut-out desulfurization and carbon residue removal reaction zone are controlled so that the density reduction value of the cleaning oil after the hydrogenation cleaning treatment is 10-30 kg/m³More preferably 15 to 25kg/m³。

Preferably, the fixed bed hydrogenation device is filled with a hydrogenation protection catalyst, a hydrogenation demetallization catalyst, a hydrodesulfurization catalyst and a carbon residue hydroconversion catalyst, and carriers in the hydrogenation protection catalyst, the hydrogenation demetallization catalyst, the hydrodesulfurization catalyst and the carbon residue hydroconversion catalyst are respectively and independently selected from at least one of alumina, silica and titania. More preferably, the support is a modified support obtained after modification with an element selected from the group consisting of boron, germanium, zirconium, phosphorus, chlorine, and fluorine.

Preferably, the active metal components in the hydrogenation protection catalyst, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the carbon residue hydroconversion catalyst are each independently at least one of non-noble metal elements selected from groups VIB and VIII; more preferably, the active metal components in the hydrogenation protection catalyst, the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the carbon residue hydroconversion catalyst are each independently at least one combination of nickel-tungsten, nickel-tungsten-cobalt, nickel-molybdenum and cobalt-molybdenum.

Preferably, the reactor a and the reactor B of the present invention have the same size and the same catalyst loading.

The aforementioned catalysts of the present invention may be selected from commercial catalysts conventional in the art or prepared by conventional methods of the prior art.

The packing volume ratio of each kind of catalyst in the process of the present invention is not particularly limited, and may be a packing volume ratio of a catalyst conventionally used in hydrotreating residual oil in the art. One loading volume ratio for each catalyst is exemplified in the examples of the present invention, and those skilled in the art should not be construed as limiting the present invention.

Preferably, the feedstock residue is a vacuum residue and/or an atmospheric residue.

Preferably, the colloidal stability factor of the first material is not greater than 2.0. The polymerization of asphaltenes in the raw residue was characterized by the change in conductivity in mass fraction of the raw residue during the addition of n-heptane, and the (n-heptane/residue) ratio at which asphaltene polymerization occurred was defined as the colloid stability factor.

Preferably, the fixed bed hydrogenation apparatus of the present invention comprises a fixed bed hydrogenation reactor, and the fixed bed reactor comprises at least one of an upflow fixed bed reactor, a downflow fixed bed reactor and a countercurrent fixed bed reactor. The downflow type fixed bed reactor refers to a fixed bed reactor with material flow flowing from top to bottom; the upflow fixed bed reactor refers to a fixed bed reactor with material flow flowing from bottom to top; the counter-flow fixed bed reactor refers to a fixed bed reactor with liquid and gas flow directions opposite.

In the method of the present invention, the step of performing the hydrotreating process using the cleaning oil and the step of the hydrogenation reaction may be repeated a plurality of times. Further, when the hydrogen washing treatment and the hydrogenation reaction are repeatedly performed, the conditions of each washing treatment and each hydrogenation reaction and the kind of the used washing oil are not particularly limited, and are not always required to be the same for each time, and it is possible to extend the operation period of the apparatus and to easily remove the agent within the range defined in the present invention.

The following description of the process (process flow) for processing a residua feedstock of the present invention is provided in connection with FIG. 1 as a preferred embodiment:

as shown in figure 1, when the device is started, the valve 01, the valve 04 and the valve 05 are opened, the valve 02, the valve 03 and the valve 06 are closed, the first material 5 sequentially enters the protective reaction zone 1, the demetallization reaction zone 2, the first reactor 8 of the desulfurization and carbon residue removal reaction zone, the reactor A3 and the reactor B4, and after the operation for a period of time,

when the pressure drop in the reactor A3 reaches the upper limit of the pressure drop or the radial temperature difference is too large due to the hot spot of the catalyst in the reactor A3, or when the fixed bed hydrogenation device continuously operates for more than 15 days, the valve 03 is opened, the valve 01 is closed, and the material flow from the first reactor 8 in the desulfurization and carbon residue removal reaction zone directly enters the reactor B4; the second material 6 enters a reactor A3, then is mixed with the material flow from the first reactor 8 of the desulfurization and carbon residue removal reaction zone, enters a reactor B4 and further exits the device. Preferably, when the reactor 3A is cleaned for a period of time to make the pressure drop therein and the radial temperature difference in the reactor return to within the preset value range, the introduction of the second material 6 into the reactor A3 is stopped, more preferably, the cleaning oil in the second material 6 is switched back to the first material 5, the valve 06 and the valve 02 are opened, the valve 05 and the valve 04 are closed, and the reaction effluent in the reactor B4 is introduced into the reactor A3 for hydrogenation reaction and then is discharged out of the device;

when the pressure drop in the reactor B4 reaches the upper limit of the pressure drop or the catalyst therein is hot to cause an excessive radial temperature difference, or when the fixed bed hydrogenation apparatus continues to operate for more than 15 days, the valves 03, 04 and 05 are closed, the valves 01, 02 and 06 are opened, the purge oil is cut out from the first material 5, and the reactor B4 is cut out, and a third material 7 containing hydrogen and the purge oil is introduced into the cut-out reactor B4 to perform a hydro-purge treatment in the reactor B4; and the reaction effluent from the first reactor 8 of the desulfurization and carbon residue removal reaction zone and the reaction effluent from the reactor B4 are introduced into the reactor A3 together to be subjected to hydrogenation reaction and then discharged out of the device; preferably, when the pressure drop in the reactor B4 and the radial temperature difference in the reactor return to within preset values, valves 02, 03 and 06 are closed, valves 01, 04 and 05 are opened, and the introduction of the third material 7 into the reactor B4 is stopped; more preferably, the cleaning oil in the third material 7 is switched back to the first material 5, and the reaction effluent in the reactor A3 is introduced into the reactor B4 for hydrogenation reaction and then discharged out of the device;

the operations are repeated, and the reactor A3 and the reactor B4 are alternately introduced into the cleaning oil for a period of time and then are incorporated into the residual oil hydrogenation reaction process until the device is shut down.

In particular, the process (process flow) and system for processing a residual oil feedstock of the present invention are not limited to the form shown in fig. 1, but should be in all ways encompassed by the foregoing technical solutions of the present invention, and those skilled in the art should not be construed as limiting the present invention.

Compared with the prior art, the method provided by the invention also has the following specific advantages:

(1) after a desulfurization and carbon residue removal reactor connected in series is cut out, cleaning oil and a small amount of hydrogen are introduced into the cut-out reactor, and residual oil raw materials in the reactor can be replaced;

(2) when the reactor is cut out, the carbon deposition amount on the catalyst is high, the activity is relatively low, and the reaction temperature rise is not too high even if cleaning oil is introduced;

(3) after the reactor of the desulfurization and carbon residue removal reaction area is cut out, the device is still in continuous operation, and after cleaning oil is introduced into the cut-out reactor, the cleaning oil can perform a carbon removal reaction with carbon deposited on the catalyst to remove the carbon deposited on the catalyst, so that the activity of the catalyst is recovered, and the operation period of the device is prolonged;

(4) the method of the invention can also make the catalyst in the reactor of the desulfurization and carbon residue removal reaction zone easier to unload;

(5) the method of the invention has flexible operation and can flexibly adjust the process conditions and the process according to the actual production needs.

The present invention will be described in detail below by way of examples. In the following examples, various raw materials used are commercially available without specific description.

The catalysts used below were all the catalysts of the residual oil hydrotreating series developed by the institute of petrochemical science and technology of petrochemical industry in China and produced by catalyst ChangLing division. Wherein RG series is hydrogenation protection catalyst, RDM series is hydrogenation demetalization catalyst, RMS series is hydrogenation desulfurization catalyst, and RCS is catalyst for hydrogenation conversion of carbon residue.

The properties of the feedstock residue, the purge oil and the blend oil are shown in table 1.

The examples and comparative examples were conducted on a pilot plant as shown in FIG. 1 (maximum design pressure drop of reactor 0.8MPa), where the catalyst loading in guard reaction zone 1 was 40mL and the catalyst loading in demetallization reaction zone 2, desulfurization and decarbonization reaction zone first reactor 8, reactor A3 and reactor B4 were all 100mL in FIG. 1.

Protecting the catalyst RG-30B filled in the reaction zone 1;

RDM-32 catalyst is filled in the demetallization reaction zone 2;

the first reactor 8 of the desulfurization and carbon residue removal reaction zone is sequentially filled with RDM-33B catalyst and RMS-30 catalyst, and the filling volume ratio of the RDM-33B catalyst to the RMS-30 catalyst is 20: 80.

Both reactor A3 and reactor B4 were sequentially packed with RCS-30 catalyst and RCS-31 (the packing volume ratio of the two was 40: 60).

Example 1

Raw material residual oil and hydrogen sequentially enter a protection reaction zone 1, a demetallization reaction zone 2, a first reactor 8 of a desulfurization and carbon residue removal reaction zone, a reactor A3 and a reactor B4, and residual oil hydrogenation process conditions in a fixed bed hydrogenation device comprise that: the volume space velocity is 0.195h^-1The volume ratio of hydrogen to oil is 700:1, and the hydrogen partial pressure is 15.0 MPa;

the product properties after residual oil hydrotreatment are kept as follows by adjusting the reaction temperature in the whole operation period: the sulfur content is 0.15 wt%, the nitrogen content is 0.30 wt%, the carbon residue value is 6.0 wt%, and the heavy metal (Ni + V) is 20 mu g/g, so that the requirement of RFCC feeding is met.

After the device continuously operates for 4 months, directly introducing outlet material flow of a first reactor 8 of a desulfurization and carbon residue removal reaction zone into a reactor B4, introducing cleaning oil A and a small amount of hydrogen into a reactor A3, introducing outlet effluent of a reactor A3 into a reactor B4, adding cleaning oil A into the reactor A3, stopping introducing the cleaning oil A after 1 month of operation, introducing outlet material flow of a reactor B4 into a reactor A3, after 3 months of operation, directly introducing outlet material flow of the first reactor 8 of the desulfurization and carbon residue removal reaction zone into the reactor A3, introducing the cleaning oil A and a small amount of hydrogen into the reactor B4, introducing outlet effluent of the reactor B4 into a reactor A3, adding cleaning oil A into the reactor B4, operating for 1 month, stopping introducing the cleaning oil A, introducing outlet material flow of the reactor A3 into a reactor B4, and protecting the reaction zone 1, the demetallization reaction zone 2 and the first reactor 8 of the desulfurization and carbon residue removal reaction zone at the moment, The average reaction temperature of reactor a3 and reactor B4 was 386 ℃, indicating that both catalysts were still active.

The weight ratio of the cleaning oil a to the feedstock residue applied in the process of this example was 18: 82, the reaction conditions in the reactor A3 or the reactor B4 when the purge oil A was introduced were a hydrogen partial pressure of 15.0MPa, a hydrogen-oil volume ratio of 100, and a volume space velocity of 0.185h^-1The density of the cleaning oil A is reduced to 16kg/m by controlling the reaction temperature³。

Example 2

Raw material residual oil and hydrogen sequentially enter a protection reaction zone 1, a demetallization reaction zone 2, a first reactor 8 of a desulfurization and carbon residue removal reaction zone, a reactor A3 and a reactor B4, and residual oil hydrogenation process conditions in a fixed bed hydrogenation device comprise that: the volume space velocity is 0.20h^-1The volume ratio of hydrogen to oil is 750:1, and the hydrogen partial pressure is 15.0 MPa.

After the device continuously operates for 6 months, the outlet material flow of the first reactor 8 of the desulfurization and carbon residue removal reaction zone is directly introduced into a reactor B4, cleaning oil B and a small amount of hydrogen gas enter a reactor A3, the outlet effluent of the reactor A3 enters a reactor B4, cleaning oil B is stopped after the cleaning oil B is added into the reactor A3 and operates for 1 month, and the outlet material flow of the reactor B4 is introduced into a reactor A3, at the moment, the average reaction temperature of the protection reaction zone 1, the demetallization reaction zone 2, the desulfurization and carbon residue removal reaction zone first reactor 8, the reactor A3 and the reactor B4 is 382 ℃, which indicates that the catalysts are all active.

The weight ratio of the cleaning oil B to the feedstock residue applied in the process of this example is 25: 75, the reaction conditions in the reactor A3 when the purge oil B was introduced were a hydrogen partial pressure of 15.0MPa, a hydrogen-oil volume ratio of 240, and a volume space velocity of 0.285h^-1The density of the cleaning oil B is reduced to 22kg/m by controlling the reaction temperature³。

Example 3

The mixed oil and hydrogen sequentially enter a protection reaction zone 1, a demetallization reaction zone 2, a first reactor 8 of a desulfurization and carbon residue removal reaction zone, a reactor A3 and a reactor B4, and residual oil hydrogenation process conditions in a fixed bed hydrogenation device comprise that: the volume space velocity is 0.224h^-1The volume ratio of hydrogen to oil is 700:1, and the hydrogen partial pressure is 15.0 MPa.

The product properties after residual oil hydrotreatment are kept as follows by adjusting the reaction temperature in the whole operation period: the sulfur content is 0.12 wt%, the nitrogen content is 0.28 wt%, the carbon residue value is 5.8 wt%, and the heavy metal (Ni + V) is 18 mu g/g, so that the requirement of RFCC feeding is met.

After the device continuously operates for 4 months, introducing a residual oil raw material in the mixed oil into a protection reaction zone 1, directly introducing an outlet material flow of a first reactor 8 in a desulfurization and carbon residue removal reaction zone into a reactor B4, introducing cleaning oil A and a small amount of hydrogen in the mixed oil into a reactor A3, introducing an outlet effluent of a reactor A3 into a reactor B4, adding the cleaning oil A into the reactor A3, operating for 1 month, stopping introducing the cleaning oil A, introducing an outlet material flow of the reactor B4 into a reactor A3, and controlling the average reaction temperature of the protection reaction zone 1, the demetallization reaction zone 2, the first reactor 8 in the desulfurization and carbon residue removal reaction zone, the reactor A3 and the reactor B4 to be 378 ℃.

The reaction conditions in the reactor A3 when the purge oil A was introduced were a hydrogen partial pressure of 15.0MPa, a hydrogen-oil volume ratio of 100, and a volume space velocity of 0.126h^-1Through control ofThe reaction temperature is controlled so that the density of the cleaning oil A is reduced by 16kg/m³。

Comparative example 1

Raw material residual oil and hydrogen sequentially enter a protection reaction zone 1, a demetallization reaction zone 2, a first reactor 8 of a desulfurization and carbon residue removal reaction zone, a reactor A3 and a reactor B4, and residual oil hydrogenation process conditions in a fixed bed hydrogenation device comprise that: volume space velocity of 0.195h^-1The volume ratio of hydrogen to oil is 700:1, and the hydrogen partial pressure is 15.0 MPa.

After the device is continuously operated for 9 months, the average reaction temperature of the protection reaction zone 1, the demetallization reaction zone 2, the first reactor 8 of the desulfurization and carbon residue removal reaction zone, the reactor A3 and the reactor B4 is 390 ℃.

Comparative example 2

After the device is continuously operated for 5 months, the average reaction temperature of the protection reaction zone 1, the demetallization reaction zone 2, the first reactor 8 of the desulfurization and carbon residue removal reaction zone, the reactor A3 and the reactor B4 is 384 ℃.

As can be seen from the results of examples 1-3 and comparative examples 1-2, the method provided by the invention can remarkably prolong the running period of the device, and the average reaction temperature of the catalyst is lower, which shows that the catalytic activity of the catalyst in the desulfurization and carbon residue removal reaction zone is better.

Example 4

Raw material residual oil and hydrogen sequentially enter a protection reaction zone 1, a demetallization reaction zone 2, a first reactor 8 of a desulfurization and carbon residue removal reaction zone, a reactor A3 and a reactor B4, and residual oil hydrogenation process conditions in a fixed bed hydrogenation device comprise that: the volume space velocity is 0.22h^-1The volume ratio of hydrogen to oil is 700:1, and the hydrogen partial pressure is 15.0 MPa. When the apparatus was started, the pressure drop in reactor A3 was 0.20 MPa.

After the device is continuously operated for 6000 hours, the pressure drop of the reactor A3 is increased to 0.70MPa, material flow is directly introduced into the reactor B4 from the first reactor 8 of the desulfurization and carbon residue removal reaction zone, cleaning oil A and a small amount of hydrogen enter the reactor A3, the effluent at the outlet of the reactor A3 enters the reactor B4, and the protection reaction zone 1, the demetallization reaction zone 2, the first reactor 8 of the desulfurization and carbon residue removal reaction zone, the reactor A3 and the reactor B4 are serially stopped after the device is operated for 1000 hours.

The weight ratio of the cleaning oil a to the feedstock residue applied in the process of this example was 18: 82, the reaction conditions in the reactor A3 when the purge oil A was introduced were a hydrogen partial pressure of 15.0MPa, a hydrogen-oil volume ratio of 100 and a volume space velocity of 0.208h^-1The density of the cleaning oil A is reduced to 16kg/m by controlling the reaction temperature³。

Example 5

After the device is continuously operated for 6000 hours, the pressure drop of the reactor A3 is increased to 0.70MPa, material flow is directly introduced into the reactor B4 from the first reactor 8 of the desulfurization and carbon residue removal reaction zone, cleaning oil B and a small amount of hydrogen enter the reactor A3, the effluent at the outlet of the reactor A3 enters the reactor B4, and after the device is operated for 2000 hours, the protection reaction zone 1, the demetallization reaction zone 2, the first reactor 8 of the desulfurization and carbon residue removal reaction zone, the reactor A3 and the reactor B4 are serially connected and shut down.

The mass ratio of the cleaning oil B to the residual oil raw material applied in the process of the embodiment is 10: 90, the reaction conditions in the reactor A3 when the purge oil B was introduced were a hydrogen partial pressure of 15.0MPa, a hydrogen-oil volume ratio of 240, and a volume space velocity of 0.105h^-1The density of the cleaning oil B is reduced to 22kg/m by controlling the reaction temperature³。

Example 6

The mixed oil and hydrogen sequentially enter a protection reaction zone 1, a demetallization reaction zone 2, a first reactor 8 of a desulfurization and carbon residue removal reaction zone, a reactor A3 and a reactor B4, and residual oil hydrogenation process conditions in a fixed bed hydrogenation device comprise that: the volume space velocity is 0.253h^-1The volume ratio of hydrogen to oil is 700:1, and the hydrogen partial pressure is 15.0 MPa. When the device was started, the pressure drop in reactor B4 was 0.18 MPa.

After the device continuously operates for 6000 hours, the pressure drop of the reactor B4 is increased to 0.70MPa, raw material residual oil in the mixed oil enters the protective reaction zone 1, cleaning oil A and a small amount of hydrogen in the mixed oil enter the reactor B4, effluent at the outlet of the reactor B4 enters the reactor A3, material flow at the outlet of the reactor A3 directly exits the device, and the protective reaction zone 1, the demetallization reaction zone 2, the first reactor 8 of the desulfurization and carbon residue removal reaction zone, the reactor A3 and the reactor B4 are shut down in series after the device operates for 800 hours.

Reaction conditions in reactor B4 when purge oil A was introducedThe hydrogen partial pressure is 15.0MPa, the hydrogen-oil volume ratio is 100, and the volume space velocity is 0.142h^-1The density of the cleaning oil A is reduced to 16kg/m by controlling the reaction temperature³。

Comparative example 3

Raw material residual oil and hydrogen sequentially enter a protection reaction zone 1, a demetallization reaction zone 2, a first reactor 8 of a desulfurization and carbon residue removal reaction zone, a reactor A3 and a reactor B4, and residual oil hydrogenation process conditions in a fixed bed hydrogenation device comprise that: volume space velocity of 0.22h^-1Hydrogen-oil volume ratio of 700:1, the hydrogen partial pressure is 15.0 MPa. When the apparatus was started, the pressure drop in reactor A3 was 0.20 MPa.

After the device is continuously operated for 6000h, the pressure drop of the reactor A3 is increased to 0.70MPa, material flow is directly introduced into the reactor B4 from the first reactor 8 of the desulfurization and carbon residue removal reaction zone, a small amount of hydrogen enters the reactor A3 to purge and maintain the temperature, and the device is operated for 1000 h and then the protection reaction zone 1, the demetallization reaction zone 2, the reactor A3 and the reactor B4 are shut down in series.

Comparative example 4

After the device is continuously operated for 6000h, the pressure drop of the reactor B4 is increased to 0.70MPa, the material flow at the outlet of the reactor A3 is directly discharged out of the device, a small amount of hydrogen enters the reactor B4 to purge and maintain the temperature, and the device is operated for 800 hours, and then the protection reaction zone 1, the demetallization reaction zone 2, the first reactor 8 of the desulfurization and carbon residue removal reaction zone, the reactor A3 and the reactor B4 are connected in series to shut down.

Comparative example 5

Raw material residual oil and hydrogen sequentially enter a protection reaction zone 1, a demetallization reaction zone 2, a first reactor 8 of a desulfurization and carbon residue removal reaction zone, a reactor A3 and a reactor B4, cleaning oil A is introduced into a hydrogenation device from an inlet of the first reactor 8 of the desulfurization and carbon residue removal reaction zone, and residual oil hydrogenation process conditions in a fixed bed hydrogenation device comprise: the volume space velocity is 0.220h^-1The volume ratio of hydrogen to oil is 700:1, and the hydrogen partial pressure is 15.0 MPa. When the device was started, the pressure drop in reactor B4 was 0.18 MPa.

In this comparative example, the weight ratio of the amount of residuum feedstock to wash oil a was 87: 13.

the carbon deposit on the catalyst packed in the first reactor or reactor a3 was analyzed after the shut-down of examples 4-6 and comparative examples 3-5, respectively, and the results of the analysis are shown in tables 2 and 3. From tables 2 and 3, it can be seen that the carbon deposition in examples 4 to 6 is greatly reduced compared with the corresponding comparative examples, and the catalyst in the reactor is easily discharged.

Table 1: properties of raw residue and cleaning oil and their blends

Table 2: average content of char on catalyst in the first reactor 8 (g/100g fresh catalyst)

Table 3: average content of char on catalyst in reactor A3 (g/100g fresh catalyst)

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A method of processing a residua feedstock, the method comprising: under the condition of hydrotreatment, introducing a first material containing raw material residual oil into a fixed bed hydrogenation device sequentially comprising a protection reaction zone, a hydrodemetallization reaction zone and a desulfurization and decarburization reaction zone which are connected in series for hydrogenation reaction, wherein the desulfurization and decarburization reaction zone at least comprises two reactors which are sequentially connected in series and are respectively a reactor A and a reactor B, and the material from the upstream of the reactor A sequentially enters the reactor A and the reactor B for hydrogenation reaction and then is discharged out of the device;

2. The method according to claim 1, wherein, in the step (a), when the pressure drop in the cut-out reactor and the radial temperature difference in the reactor are recovered within preset values while the cut-out reactor is subjected to the hydro-cleaning process, the introduction of the second material into the cut-out reactor is stopped, and the reaction effluent in the uncut reactor is introduced into the cut-out reactor to be subjected to the hydrogenation reaction and then discharged from the apparatus.

3. The method according to claim 1, wherein the conditions of the reactor a or the reactor B are controlled so that the reactor a or the reactor B is in a state where the hydrotreating process has been performed for at least 24 hours while the fixed-bed hydrogenation apparatus is stopped online.

4. A process according to claim 1, wherein the total aromatics content in the wash oil is from 80 to 90 wt.%.

5. A process according to any one of claims 1 to 4, wherein the cleaning oil has a bicyclic aromatic content of 30 to 80 wt%.

6. A process as claimed in claim 5, wherein the bicyclic aromatic content of the wash oil is from 50 to 70 wt%.

7. The method of claim 1, wherein the wash oil is selected from at least one of straight-run diesel, catalytic cracking cycle oil, and catalytic cracking slurry oil.

8. The process of any of claims 1-4, wherein the upper pressure drop limit is 40 to 80% of the maximum design pressure drop of the corresponding reactor in the desulfurization and carbon residue removal reaction zone.

9. The process of claim 8, wherein the upper pressure drop limit is 45 to 75% of the maximum design pressure drop of the corresponding reactor in the desulfurization and carbon residue removal reaction zone.

10. The process according to any one of claims 1 to 4, wherein the radial temperature difference of the reactor is 15 to 40 ℃.

11. The process of claim 10, wherein the radial temperature difference of the reactor is 20 to 35 ℃.

12. The method according to claim 8, wherein, in the step (a), the continuous operation time of the hydrogenation reaction before the reactor A and the reactor B are cut out for hydrogenation cleaning treatment is 1/8-1/2 of the continuous operation period of the fixed bed hydrogenation device.

13. The method according to claim 12, wherein, in step (a), the continuous operation time of the hydrogenation reaction before each cut-out of the reactor A and the reactor B for the hydro-cleaning treatment is 1/4-1/3 of the continuous operation period of the fixed bed hydrogenation apparatus.

14. The method according to claim 8, wherein in the step (a), the time for which the reactor A and the reactor B are cut out for the hydro-cleaning treatment each time is 1/16-1/4 of the continuous operation period of the fixed bed hydrogenation device.

15. The method of claim 14, wherein in step (a), the time for which the reactor A and the reactor B are cut out for the hydro-cleaning treatment each time is 1/8-1/6 of the continuous operation period of the fixed bed hydrogenation apparatus.

16. The process according to any one of claims 1 to 4, wherein the weight ratio of the amount of the feedstock residue in the first material to the washing oil in step (a) is 10: (1-4.5).

17. The method according to any one of claims 1 to 4, wherein the first material further contains a cleaning oil, and in performing step (a), the cleaning oil in the first material is cut out to be introduced into the cut-out reactor for a hydro-cleaning treatment.

18. The method according to claim 16, wherein, in the step (a), when the pressure drop in the cut-out reactor and the radial temperature difference in the reactor are recovered within preset values while the cut-out reactor is subjected to the hydro-cleaning process, the introduction of the second material into the cut-out reactor is stopped, and the cleaning oil in the second material is switched back to the first material, and the reaction effluent in the uncut reactor is introduced into the cut-out reactor to be subjected to the hydro-reaction and then discharged out of the apparatus.

19. The method of any one of claims 1-4, wherein both fixed bed hydrogenation units before and after reactor A or reactor B are cut out of the desulfurization and carbon residue removal reaction zone are residual hydrogenation process conditions comprisingComprises the following steps: the hydrogen partial pressure is 5.0-22.0 MPa, the reaction temperature is 330-450 ℃, and the volume space velocity is 0.1-3.0 h^-1The volume ratio of hydrogen to oil is 350-2000.

20. The method of claim 19, wherein the cut-out conditions of the hydro-cleaning process in reactor a or reactor B in the desulfurization and carbon residue removal reaction zone comprise: the hydrogen partial pressure is 5.0-22.0 MPa, the reaction temperature is 300-400 ℃, the hydrogen-oil volume ratio is 50-300, and the volume space velocity is 1.0-3.0 times of the volume space velocity of the hydrogenation reaction.

21. The method according to claim 20, wherein the conditions of the hydro-cleaning treatment in the reactor A or the reactor B in the cut-out desulfurization and carbon residue removal reaction zone are controlled so that the density reduction value of the cleaning oil after the hydro-cleaning treatment is 10-30 kg/m³。

22. The method according to claim 21, wherein the conditions of the hydro-cleaning treatment in the reactor A or the reactor B in the cut-out desulfurization and carbon residue removal reaction zone are controlled so that the density reduction value of the cleaning oil after the hydro-cleaning treatment is 15 to 25kg/m³。

23. The method of claim 1, wherein the fixed bed hydrogenation unit is packed with a hydrogenation protection catalyst, a hydrodemetallization catalyst, a hydrodesulfurization catalyst, and a carbon residue hydroconversion catalyst, and the support of the hydrogenation protection catalyst, the hydrodemetallization catalyst, the hydrodesulfurization catalyst, and the carbon residue hydroconversion catalyst is each independently selected from at least one of alumina, silica, and titania.

24. The method according to claim 23, wherein the support is a modified support obtained after modification with an element selected from boron, germanium, zirconium, phosphorus, chlorine, and fluorine.

25. The process of claim 23, wherein the active metal component of the hydro-protective catalyst, hydrodemetallization catalyst, hydrodesulfurization catalyst, and carbon residue hydroconversion catalyst is each independently at least one of a non-noble metal element selected from group VIB and group VIII.

26. The process of claim 25, wherein the active metal components in the hydro-protective catalyst, hydrodemetallization catalyst, hydrodesulfurization catalyst, and carbon residue hydroconversion catalyst are each independently at least one combination of nickel-tungsten, nickel-tungsten-cobalt, nickel-molybdenum, and cobalt-molybdenum.

27. A process according to claim 1 in which the feed resid is a vacuum resid and/or an atmospheric resid.

28. The method of claim 1, wherein the first material has a colloidal stability factor of no greater than 2.0.