CN107794083B

CN107794083B - Hydrocarbon raw material fixed bed hydrogenation system and method thereof

Info

Publication number: CN107794083B
Application number: CN201610807793.7A
Authority: CN
Inventors: 邵志才; 邓中活; 孙淑玲; 戴立顺; 刘涛; 施瑢; 杨清河; 胡大为
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petrochemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petrochemical Corp
Priority date: 2016-09-07
Filing date: 2016-09-07
Publication date: 2020-01-10
Anticipated expiration: 2036-09-07
Also published as: CN107794083A

Abstract

The fixed bed hydrogenation system comprises a pretreatment reaction area, a first gas-liquid separation area, a main reaction area and a second gas-liquid separation area, wherein at least one fixed bed reactor is arranged in the pretreatment reaction area, at least one hydrogenation protective agent and at least one first hydrogenation demetallizing agent are sequentially filled in the fixed bed reactor along the material flow direction, at least one fixed bed reactor is arranged in the main reaction area, and at least one second hydrogenation demetallizing agent and at least one hydrogenation desulfurizing agent are sequentially filled in the fixed bed reactor along the material flow direction. The system provided by the invention has high iron capacity of the pretreatment reaction zone and high iron interception capacity of the pretreatment reaction zone. The problem of insufficient interception capability of iron-containing compounds when a pretreatment reaction zone runs for a long period in the prior art is solved.

Description

Hydrocarbon raw material fixed bed hydrogenation system and method thereof

Technical Field

The invention relates to a hydrogenation system and a hydrogenation method for a hydrocarbon raw material, in particular to a fixed bed hydrogenation system and a fixed bed hydrogenation method for the hydrocarbon raw material.

Background

Reactor pressure drop is one of the major factors that limit the operating cycle of a hydrocarbon hydrotreating or hydrofinishing unit. Taking a fixed bed residue hydrogenation process as an example, the operation cycle of the fixed bed residue hydrogenation device is generally from one year to one and a half years at present, while the operation cycle of the fixed bed residue hydrogenation device with a higher iron content is generally shorter, and the main limiting factor is the pressure drop of the first reaction or the second reaction. Different from the condition that metals such as nickel, vanadium and the like are mainly deposited in catalyst pore channels, iron is mainly deposited on the outer surface of a catalyst after being subjected to ferrous sulfide generation under the hydrogenation condition, the deposition amount in the catalyst pores is small, the void ratio of a catalyst bed layer is rapidly reduced, the rapid reduction of the void ratio of the catalyst bed layer can cause the pressure drop of a reactor to rapidly rise and finally lead a device to be shut down in advance, and unnecessary economic loss is caused.

Common methods for delaying the pressure drop increase in industry include: (1) the loading of the protectant is increased, but the process reduces the loading of the procatalyst. (2) A guard reactor that can be thrown off is used, which is short-circuited when the pressure drop increases to the design limit, and the stream goes directly to the second reactor, but this method will cause half the period of the guard reactor to be unusable. (3) A moving bed reactor is adopted, but the investment is greatly increased. (4) The switching protection reactor is adopted, the switching process is complex and the investment is increased.

US6554994B1 uses an upflow reactor as a guard reactor, which improves the metal-tolerant capacity of the catalyst due to slight catalyst expansion during normal operation of the upflow reactor. However, in the case of processing a high iron content raw material, although the rate of increase in pressure drop is not rapid in the opposite direction, iron is deposited in the rear fixed bed reactor during a long period of operation, resulting in an increase in pressure drop in the reactor.

CN1322097C discloses a method for hydrotreating heavy hydrocarbons with a switchable guard reactor, which is to arrange a switchable guard reactor system in front of a main reactor to remove heavy metal impurities and coking scaling substances in raw materials, thereby achieving the purpose of protecting the main catalyst. The protective reactor in the method needs to be switched to operate under the conditions of high temperature and high pressure, and the operation risk is high.

CN1335368A discloses a heavy residual oil hydrotreating method, which uses a first-stage adsorbent filter bed or a first-stage adsorbent filter bed and a first-stage adsorption filter catalyst bed to remove suspended particles in heavy residual oil and ferrous sulfide generated by iron naphthenate. However, in the method, the bed layer of the adsorption filter can only remove suspended particles, and the bed layer of the adsorption filtration catalyst needs to be operated under higher pressure, higher temperature and higher hydrogen-oil ratio, which is actually equivalent to the method of increasing the loading of the protective agent in the main reactor for residual oil hydrogenation, so that the loading of the main catalyst is reduced.

CN201110326424 and CN201110326504 disclose a hydrotreating method of high acid and high calcium heavy crude oil. In the method, high-acid high-calcium heavy crude oil is mixed with hydrogen and then enters a low-pressure hydrotreating system for pretreatment, and only a hydrogenation protective agent is filled in a reactor of the pretreatment system. Research shows that the iron-containing compounds still enter the subsequent treatment device and still affect the subsequent treatment device, and the effects of fundamentally removing and effectively intercepting the iron-containing compounds are not achieved.

Disclosure of Invention

The invention aims to overcome the defect that the pressure drop of a reactor is increased quickly when the existing hydrogenation method is used for processing hydrocarbon raw materials with high iron content, and provides a fixed bed hydrogenation system for the hydrocarbon raw materials and a hydrogenation method thereof.

The invention provides a fixed bed hydrogenation system for hydrocarbon raw materials, which comprises a pretreatment reaction area, a first gas-liquid separation area, a main reaction area and a second gas-liquid separation area, wherein an inlet of the pretreatment reaction area is communicated with a raw material feeding line, an outlet of the pretreatment reaction area is communicated with an inlet of the first gas-liquid separation area, the first gas-liquid separation area is provided with a gas phase material flow I outlet and a liquid phase material flow I outlet, the liquid phase material flow I outlet is communicated with an inlet of the main reaction area, an outlet of the main reaction area is communicated with an inlet of the second gas-liquid separation area, and the second gas-liquid separation area is provided with a gas phase material flow II outlet and a liquid phase; set up at least one fixed bed reactor in the preliminary treatment reaction zone, pack at least one hydrogenation protective agent and at least one first hydrogenation demetallization agent in proper order along the commodity circulation direction in fixed bed reactor, wherein, the particle diameter of the first hydrogenation demetallization agent that packs at commodity circulation direction end position is not more than 1.3mm, set up at least one fixed bed reactor in the main reaction zone, pack at least one second hydrogenation demetallization agent and at least one hydrodesulfurization agent in proper order along the commodity circulation direction in fixed bed reactor.

The iron in the crude oil after the electro-desalting is mainly oil-soluble, the oil-soluble iron comprises iron oleate, iron porphyrin and non-iron porphyrin, and the proportion of the three types of iron is different according to different raw material sources. The inventor of the invention researches and discovers that most of the iron oleate is easier to react and can be removed by thermal cracking reaction under the non-hydrogen condition in terms of reaction performance, and the removal of porphyrin iron and non-porphyrin iron is relatively difficult and needs to reach higher removal rate at higher reaction temperature. Under typical hydrotreating conditions, the removal of iron oleate is relatively easy, and can be realized only at a relatively high reaction temperature when the crude oil as a whole reaches a relatively high iron removal rate.

In the existing fixed bed residual oil hydrogenation process, the basic principle of catalyst grading is that the aperture of the catalyst is gradually reduced along the material flow direction, the content of active components is gradually reduced, and the particle size of the catalyst is gradually reduced. However, when the existing fixed bed residual oil hydrogenation catalyst grading technology is directly used for a device with a low hydrogen partial pressure pretreatment area, because the pretreatment area needs to be operated at a higher reaction temperature and the hydrogen partial pressure is low, the proportion of thermal cracking reaction in the pretreatment reactor is increased, and colloid and asphaltene macromolecules are easy to generate the polycondensation reaction of dehydrogenation, so that macromolecules with higher condensation degree are generated. These very high condensation macromolecules can deposit in the form of carbon deposits on the catalyst in the main reactor, leading to a relatively rapid deactivation of the catalyst. Thus, existing fixed bed catalyst staging techniques are not applicable to the pretreatment reaction zone of the present invention.

In addition, industrial application results show that the pressure drop of one reaction or two reactions can be increased rapidly in the operation process of the fixed bed residual oil hydrogenation device with higher iron content of the raw material. The inventor of the present invention further studied intensively to find that the deposition distribution of iron in different reactors is closely related to the catalyst particle size fraction of a fixed bed device, and in addition, the uniformity of iron deposition in the reactors has an important influence on the iron holding capacity. The inventor of the present invention has conducted multi-level and multi-directional analysis of iron deposition and has determined that the reason why the protection reactor of the residual oil hydrogenation apparatus ascends too fast is caused by the non-uniformity of iron deposition in the axial direction of the reactor and in the radial direction of the catalyst particles. For example, the more uneven the distribution of iron catalyst particles in the radial direction, the faster the reactor pressure drop will rise for the same amount of iron deposited.

In order to solve the problems, the invention provides a fixed bed hydrogenation system for hydrocarbon raw materials, which comprises a pretreatment reaction zone, a first gas-liquid separation zone, a main reaction zone and a second gas-liquid separation zone. At least one fixed bed reactor is arranged in the pretreatment reaction zone, at least one hydrogenation protective agent and at least one first hydrodemetallization agent are sequentially graded in the fixed bed reactor along the material flow direction, preferably, the first hydrodemetallization agent is filled by 2-4 first hydrodemetallization agents in a combined mode, the particle size of each first hydrodemetallization agent is gradually reduced along the material flow direction, and the particle size of the first hydrodemetallization agent filled at the tail end of the material flow direction is not larger than 1.3 mm. Further preferably, the hydrodemetallization agent charged in the end portion in the direction of flow has a particle size of not more than 1.1 mm. In one embodiment of the present invention, preferably, the hydrogenation protective agent is loaded by 2-4 hydrogenation protective agents, and the particle size of each hydrogenation protective agent gradually decreases along the material flow direction.

The particle diameter in the present invention means the maximum value of the distance between any two points on the cross section of the catalyst.

The system provided by the invention has high iron capacity of the pretreatment reaction zone and high iron interception capacity of the pretreatment reaction zone. The problem of insufficient interception capability of iron-containing compounds when a pretreatment reaction zone runs for a long period in the prior art is solved.

In a preferred embodiment of the present invention, the first hydrodemetallization agent has a higher active metal component content than the second hydrodemetallization agent.

More preferably, the content of the active metal component of the first hydrodemetallization agent is 0.1-10 wt% more than that of the active metal component of the second hydrodemetallization agent.

In the present invention, the hydrogenation protection catalyst, the first hydrodemetallization agent, the second hydrodemetallization agent and the hydrodesulfurization catalyst may be respectively filled with one or more, and therefore, the active metal component content of the first hydrodemetallization agent being greater than the active metal component content of the second hydrodemetallization agent means that the average value of the active metal component contents of the first hydrodemetallization agent is greater than the average value of the active metal component contents of the second hydrodemetallization agent.

In the invention, the loading volume fraction of the hydrogenation protective agent is 20-95% and the loading volume fraction of the first hydrogenation demetallization agent is 5-80% on the basis of the whole catalyst in the pretreatment reaction zone.

In one embodiment of the invention, the loading volume fraction of the hydrogenation protective agent is 20-95% and the loading volume fraction of the first hydrodemetallization agent is 5-80% based on the whole catalyst in the pretreatment reaction zone, wherein the loading volume fraction of the first hydrodemetallization agent with the particle size of not more than 1.3mm is 5-70%.

In one embodiment of the invention, the loading volume fraction of the hydrogenation protective agent is 20-95% and the loading volume fraction of the first hydrodemetallization agent is 5-80% based on the whole catalyst in the pretreatment reaction zone, wherein the loading volume fraction of the first hydrodemetallization agent with the particle size not greater than 1.1mm is 5-70%.

The grading scheme of the hydrogenation protective agent and the hydrogenation demetallization agent can be optimized according to the pore structure and the catalyst activity of the catalyst, the material property, the hydrogenation operation condition and the like.

The hydrogenation protective agent comprises a carrier and an active component loaded on the carrier, wherein the carrier is selected from one or more of aluminum oxide, silicon oxide and titanium oxide, the active component is selected from VIB group metals and/or VIII group metals, the weight of the hydrogenation protective agent is taken as a reference, the active component accounts for 0-12 wt% of the oxide, and the balance is the carrier.

The particle size of the hydrogenation protective agent is 3-50.0 mm, and the average pore diameter is 18-4000 nm.

The first hydrodemetallization agent comprises a carrier and an active component loaded on the carrier, wherein the carrier is one or more of aluminum oxide, silicon oxide and titanium oxide, the active component is a VIB group metal and/or a VIII group metal, the weight of the first hydrodemetallization agent is taken as a reference, the active component accounts for 3-30 wt% of the oxide, and the balance is the carrier.

The first hydrodemetallization agent has a particle size of 0.8-3 mm and an average pore diameter of 10-30 nm.

The number of fixed bed reactors provided in the pretreatment reaction zone of the present invention is not particularly limited, and one fixed bed reactor may be provided.

In another preferred embodiment of the invention, 2-4 fixed bed reactors connected in parallel are arranged in the pretreatment reaction zone, wherein a plurality of fixed bed reactors can be on line simultaneously or only one fixed bed reactor is on line simultaneously.

The fixed bed reactor arranged in the pretreatment reaction zone can be a down-flow reactor, an up-flow reactor or a counter-flow reactor. The downflow reactor refers to a reactor with a material flow flowing from top to bottom; the upflow reactor refers to a reactor with material flow flowing from bottom to top; the counter-flow reactor refers to a reactor with liquid and gas flowing in opposite directions.

The invention is characterized in that at least one fixed bed reactor is arranged in the main reaction zone, and at least one second hydrodemetallization agent and at least one hydrodesulfurization agent are sequentially filled in the fixed bed reactor along the material flow direction.

Based on the whole catalyst in the main reaction zone, the filling volume fraction of the second hydrodemetallization agent is 5-70%, and the filling volume fraction of the hydrodesulfurization agent is 30-95%.

The second hydrodemetallization agent comprises a carrier and an active component loaded on the carrier, wherein the carrier is one or more selected from aluminum oxide, silicon oxide and titanium oxide, the active component is a VIB group metal and/or a VIII group metal, the active component accounts for 2.9-20 wt% of the oxide by taking the weight of the second hydrodemetallization agent as a reference, and the balance is the carrier. Preferably, the active metal component is a nickel-tungsten, nickel-tungsten-cobalt, nickel-molybdenum or cobalt-molybdenum combination.

The second hydrodemetallization agent has a particle size of 0.8-3 mm and an average pore diameter of 9.9-29.9 nm.

The hydrodesulfurization agent contains a carrier and active components loaded on the carrier, wherein the carrier is one or more selected from aluminum oxide, silicon oxide and titanium oxide, the active components are selected from VIB group metals and/or VIII group metals, the weight of the hydrodesulfurization agent is taken as a reference, the active components account for 5-35 wt% of oxides, and the balance is the carrier. Preferably, the active metal component is a nickel-tungsten, nickel-tungsten-cobalt, nickel-molybdenum or cobalt-molybdenum combination.

The particle size of the hydrodesulfurization agent is 0.6-2 mm, and the average pore diameter is 7-15 nm.

More preferably, the bulk density of the catalyst of the present invention is 0.3 to 1.2g/cm³The specific surface area is 50-400 m²/g。

According to the hydrogenation system, the pore diameter of each hydrogenation catalyst is gradually reduced, the content of active metal components is gradually increased, and the particle size is gradually reduced along the material flow direction in the main reaction zone.

In order to make the impurity removal capability of the hydrogenation system stronger and thus prolong the operation period of the hydrogenation device, in a more preferable case, the average pore diameter of the first hydrodemetallization agent is larger than the average pore diameter of the second hydrodemetallization agent.

In the system of the present invention, the main reaction zone may also be filled with any other conventional residual oil hydrogenation catalyst, such as one or more of a hydrogenation protection catalyst, a hydrogenation carbon residue removal catalyst and a hydrodenitrogenation catalyst, and the catalysts in the main reaction zone are graded according to a conventional method, that is, in the case that all the hydrogenation catalysts are present, the main reaction zone is sequentially filled with the hydrogenation protection catalyst, the second hydrogenation demetallization agent, the hydrodesulfurization catalyst, the hydrogenation carbon residue removal catalyst and the hydrodenitrogenation catalyst along the material flow direction.

The system provided by the invention can remove most of iron-containing compounds in the hydrocarbon raw materials, and has high iron capacity in the pretreatment reaction zone and high iron interception capacity in the pretreatment reaction zone. The problem of insufficient interception capability of iron-containing compounds when a pretreatment reaction zone runs for a long period in the prior art is solved. Provides good raw materials for the subsequent main reaction zone and can ensure the long-period operation of the main reaction zone, thereby increasing the operating efficiency of the whole system and improving the economy.

In a preferred embodiment of the present invention, the content of the active metal component of the first hydrodemetallization agent in the pretreatment reaction zone is increased, so that the pretreatment reaction zone realizes a higher iron removal rate at a relatively low temperature, and the proportion of thermal cracking reaction in the pretreatment reaction zone is reduced, thereby effectively reducing the carbon deposition amount of the catalyst in the main reaction zone and further prolonging the service life of the catalyst in the main reaction zone.

The hydrogenation method according to any one of the above systems, wherein the hydrocarbon raw material and the first hydrogen-containing gas are mixed and then enter a pretreatment reaction zone, and sequentially contact with a hydrogenation protective agent and a first hydrogenation demetallizing agent to react, a reaction product enters a first gas-liquid separation zone and then is separated into a gas phase material flow I and a liquid phase material flow I, the liquid phase material flow I enters a main reaction zone, and sequentially contacts with a second hydrogenation demetallizing agent and a hydrogenation desulfurizing agent to react in the presence of the second hydrogen-containing gas, the reaction product enters a second gas-liquid separation zone and then is separated into a gas phase material flow II and a liquid phase material flow II, and the hydrogen partial pressure of the pretreatment reaction zone is 0.1 MPa-4.0 MPa.

The iron content of the hydrocarbon feedstock is above 8 mug/g, preferably above 15 mug/g.

The hydrocarbon raw material is any iron-containing oil product and is selected from one or more of diesel oil, wax oil, atmospheric residue oil, vacuum residue oil, deasphalted oil, coal tar and coal-liquefied heavy oil. Preferably a hydrocarbon feedstock having a primary boiling point greater than 350 ℃.

In order to improve the diffusion properties of the hydrocarbon feedstock and to increase the uniformity of the deposition of iron in the radial direction of the catalyst particles, in a preferred embodiment, water is incorporated into the hydrocarbon feedstock and is passed together into the pretreatment reaction zone. The source of the water is not particularly limited, and deionized water is preferred. The ratio of the hydrocarbon feedstock to water is not particularly limited, and preferably the ratio of hydrocarbon feedstock to water is 100: 1 to 20, more preferably 100: 2 to 15.

In another embodiment of the invention, the water may also be provided by water produced during the reaction from the oxygen-rich hydrocarbon feedstock. The hydrocarbon raw material is mixed with the oxygen-enriched hydrocarbon raw material, and the weight ratio of the hydrocarbon raw material to the oxygen-enriched hydrocarbon raw material is 100: 1-30 percent of oxygen-enriched hydrocarbon raw material, wherein the oxygen content of the oxygen-enriched hydrocarbon raw material is 1-20 percent based on the weight of the oxygen-enriched hydrocarbon raw material.

The oxygen-enriched hydrocarbon raw material is biological grease, and preferably fatty acid triglyceride with fatty acid chains of 14-18 carbon atoms.

The hydrogen content of the first hydrogen-containing gas is 20 to 100 vol%, preferably 40 to 80 vol%. The first hydrogen-containing gas can be selected from one or more of refinery gases with the hydrogen content of 20-100 vol% in a refinery, such as catalytic cracking dry gas, coking dry gas, hydrogenation unit low-molecular gas or reforming hydrogen and the like.

The hydrogen content of the second hydrogen-containing gas is 70-100 vol%, and hydrogen production and/or reforming are preferable.

Under the condition that the hydrogen partial pressure is 0.1-4.0 MPa, other conditions of the pretreatment reaction zone can be conventional conditions in the field, the reaction temperature of the pretreatment reaction zone is 100-400 ℃, and the liquid hourly space velocity is 0.10-10.0 h^-1The volume ratio of hydrogen to oil is 10-500. Preferably, the reaction temperature of the pretreatment reaction zone is 200-370 ℃, and the liquid hourly space velocity is 0.6-6.0 h^-1The volume ratio of hydrogen to oil is 20-200.

The separation conditions of the first gas-liquid separation zone are well known to those skilled in the art, and the separation pressure in the first gas-liquid separation zone is the same as the pressure in the pretreatment reaction zone.

The reaction temperature of the main reaction zone is 300-460 ℃, and preferably 350-420 ℃; the reaction pressure is 6-25 MPa, preferably 12-20 MPa; the liquid hourly space velocity is 0.1-1 h^-1Preferably 0.2 to 0.4h^-1(ii) a The volume ratio of hydrogen to oil is 250 to 1500, preferably 300 to 1000.

The separation conditions of the second gas-liquid separation zone are well known to those skilled in the art and are conventional hydrogenation gas-liquid separation conditions.

And the gas phase material flow II obtained by the second gas-liquid separation zone can be recycled after being treated. The liquid phase material flow II obtained from the second gas-liquid separation zone can be sent to downstream devices, such as a catalytic cracking device, and products such as gasoline, diesel oil and the like can be obtained after catalytic cracking reaction.

Compared with the prior art, the method provided by the invention has the advantages that:

(1) the present invention is a process for removing iron-containing compounds from hydrocarbon feedstocks by lower pressure and lower hydrogen to oil ratio, and additionally the present invention can employ a low quality source of hydrogen having a lower hydrogen volume fraction, requiring less equipment investment and operating costs than the prior art.

(2) The method can effectively intercept the iron-containing compound in long-period operation by introducing the small-particle first hydrodemetallization agent into the rear part of the pretreatment reaction zone along the material flow direction, provides better feeding for the long-period operation treatment of the main reaction zone, and improves the economical efficiency of the operation of the whole system.

(3) In the preferred method of the invention, the diffusion performance of the hydrocarbon raw material is improved by introducing water, so that the uniformity of the iron deposition in the radial direction of the catalyst particles is increased, and the pressure drop increase of the pretreatment reaction zone is further delayed.

Drawings

The attached figure is a schematic diagram of the fixed bed hydrogenation system of the hydrocarbon raw material provided by the invention.

Detailed Description

The fixed bed hydrogenation system and the hydrogenation method for the hydrocarbon raw material provided by the invention are further described below with reference to the accompanying drawings.

As shown in the figure, the invention provides a hydrocarbon raw material fixed bed hydrogenation system, wherein one embodiment comprises a pretreatment reaction zone 1, a first gas-liquid separation zone 2, a main reaction zone 3 and a second gas-liquid separation zone 4, the inlet of the pretreatment reaction zone 1 is communicated with a raw material feeding line 5 and a first hydrogen-containing gas feeding line 6, the outlet of the pretreatment reaction zone 1 is communicated with the inlet of the first gas-liquid separation zone 2 through a pipeline 7, the gas phase material flow I outlet of the first gas-liquid separation zone 2 is connected with a gas phase material flow discharge line 8, the liquid phase material flow I outlet of the first gas-liquid separation zone 2 is communicated with the inlet of the main reaction zone 3 through a pipeline 9, and the second hydrogen-containing gas feeding line 10 is communicated with the inlet of the main reaction zone 3. The outlet of the main reaction zone 3 is communicated with the inlet of the second gas-liquid separation zone 4 through a pipeline 11, the outlet of the gas phase material flow II of the second gas-liquid separation zone 4 is connected with a discharge line 12, and the outlet of the liquid phase material flow II of the second gas-liquid separation zone is communicated with a discharge line 13.

The pretreatment reaction zone is internally provided with at least one fixed bed reactor, the fixed bed reactor is internally sequentially filled with at least one hydrogenation protective agent 1-1 and at least one first hydrogenation demetallizing agent 1-2 along the material flow direction, wherein the particle size of the first hydrogenation demetallizing agent filled at the tail end part of the material flow direction is not more than 1.3mm, the main reaction zone is internally provided with at least one fixed bed reactor, and the fixed bed reactor is internally sequentially filled with at least one second hydrogenation demetallizing agent 3-1 and at least one hydrogenation desulfurizing agent 3-2 along the material flow direction.

The following will further illustrate specific features and effects of the fixed bed hydrogenation system for hydrocarbon feedstock and the hydrogenation method thereof according to the present invention with reference to specific examples, but the present invention is not limited thereto.

The compositions and properties of the catalysts used in the examples and comparative examples are shown in Table 1, wherein G represents a hydrogenation protecting agent, M represents a hydrodemetallization agent, S represents a hydrodesulfurization agent,

numbers

1 and 2 represent different catalysts, for example M1 and M2 represent two different hydrodemetallization agents.

TABLE 1

The first hydrogen-containing gas used in each of the examples and comparative examples was refinery gas, which was a mixture of hydrogen, methane, ethane and propane in a certain ratio.

Examples 1 to 2

Examples 1 to 2 were provided with a pretreatment reaction zone, a single fixed bed reactor was provided in the pretreatment reaction zone, a hydrogenation protective agent and a first hydrodemetallization agent were sequentially filled in the reactor from bottom to top, and the catalyst loading ratio, for example, as shown in table 2, the particle size of the first hydrodemetallization agent filled in the end portion in the material flow direction was not more than 1.3 mm. The hydrocarbon raw material and the gas containing hydrogen are mixed and then enter a fixed bed reactor, and are sequentially contacted with a hydrogenation protective agent and a first hydrogenation demetallization agent for reaction, and a reaction product is extracted from the top of the fixed bed reactor, enters a first gas-liquid separation zone and is separated into a gas phase material flow and a liquid phase material flow. The hydrogen content of the hydrogen-containing gas of example 1 was 50 vol%, and the hydrogen content of the hydrogen-containing gas of example 2 was 100 vol%. The reaction conditions are shown in Table 3, and the properties of the starting materials and the properties of the products are shown in Table 4.

As can be seen from the data in table 4, the pretreatment reaction zone removes a substantial portion of the iron from the hydrocarbon feedstock, effectively protecting the subsequent primary reaction zone.

Example 3

Embodiment 3 adopts the fixed bed hydrogenation system provided by the present invention, which comprises a pretreatment reaction zone, a first gas-liquid separation zone, a main reaction zone and a second gas-liquid separation zone, wherein a fixed bed reactor is arranged in the pretreatment reaction zone, and a fixed bed reactor is arranged in the main reaction zone. Specific loading ratios of the catalysts are shown in Table 2, for example. The grain size of the first hydrodemetallization agent filled in the end part of the pretreatment reaction zone in the material flow direction is not more than 1.3 mm.

The hydrocarbon raw material and the first hydrogen-containing gas are mixed and then enter a first fixed bed reactor (R-1) to be sequentially contacted with a hydrogenation protective agent and a first hydrogenation demetallization agent for reaction, and a reaction product enters a first gas-liquid separation zone and then is separated into a gas phase material flow I and a liquid phase material flow I. And the liquid phase material flow I and the second hydrogen-containing gas are mixed and then enter a second fixed bed reactor (R-2), and are sequentially contacted with a second hydrodemetallization agent and a hydrodesulfurization agent for reaction, and the reaction effluent passes through a second gas-liquid separation zone to obtain a gas phase material flow II and a liquid phase material flow II. The hydrogen content of the first hydrogen-containing gas was 70 vol%, and the hydrogen content of the second hydrogen-containing gas was 100 vol%. The reaction conditions are shown in Table 3.

Example 3A 8000h stability test was conducted, the raw material properties and liquid phase stream II properties are shown in Table 5, wherein the iron content in the liquid phase stream I was controlled to be not more than 3 μ g/g, the sulfur content in the liquid phase stream II was controlled to be not more than 0.2 wt%, the R-1 pressure drop was 0.10MPa and the R-2 pressure drop was 0.20MPa at the start of the system operation, the R-1 pressure drop was increased to 0.55MPa, the R-2 pressure drop was 0.30MPa and the reaction temperature of R-2 was 410 deg.C after 8000h system operation.

Comparative example 1

Comparative example 1 the process flow is the same as in example 3, but the catalyst grading scheme is different, the specific loading ratio is shown in table 2, and the reaction conditions are shown in table 3.

Comparative example 1A 8000h stability test was carried out, the properties of the feed and the liquid stream II were as shown in Table 5, the iron content in the liquid stream I was controlled to not more than 3. mu.g/g, the temperature rise rate in the pretreatment zone was the same as in example 3, and the sulfur content in the liquid stream II was controlled to not more than 0.2 wt%, the pressure drop R-1 was 0.06MPa and the pressure drop R-2 was 0.17MPa at the start of the apparatus operation, the pressure drop R-1 was increased to 0.43MPa and the pressure drop R-2 was increased to 0.65MPa and the reaction temperature R-2 was 420 ℃.

As can be seen by comparison, after 8000h of operation, the pressure drop of R-2 in comparative example 1 is obviously higher than that of R-2 in example 3, and the reaction temperature of R-2 is also higher than that of example 3 by 10 ℃, so that the system provided by the invention can effectively intercept iron-containing compounds in the pretreatment reaction zone, provide better raw materials for long-period operation treatment of the main reaction zone, and improve the operation economy of the whole system.

Example 4

Example 4 the process flow is the same as in example 3, the catalyst grading loading scheme is shown in table 2, and the reaction conditions are shown in table 3.

Example 4A 8000h stability test was conducted, the raw material properties and the properties of the liquid phase stream II were as shown in Table 5, the iron content in the liquid phase stream I was controlled to be not more than 3 μ g/g, and the sulfur content in the liquid phase stream II was controlled to be not more than 0.2 wt%, when the apparatus started to operate, the pressure drop R-1 was 0.10MPa and the pressure drop R-2 was 0.20MPa, when the apparatus was operated for 8000h, the pressure drop R-1 was increased to 0.55MPa, the pressure drop R-2 was 0.29MPa, and the reaction temperature R-2 was 405 ℃.

As can be seen from the comparison between example 3 and example 4, the reaction temperature of R-2 in example 4 is 5 ℃ lower than that of R-2 in example 3, which shows that the carbon deposit inactivation speed of the main reaction zone can be effectively reduced and the operation period of the main reaction zone can be prolonged by increasing the activity of the first hydrodemetallization agent in the pretreatment reaction zone.

Example 5

Example 5 the process flow is the same as in example 3, the catalyst grading loading scheme is shown in table 2, and the reaction conditions are shown in table 3.

Example 5A 8000h stability test was conducted, the feed properties and the properties of the liquid phase stream II were as shown in Table 5, the iron content in the liquid phase stream I was controlled to be not more than 3 μ g/g, and the sulfur content in the liquid phase stream II was controlled to be not more than 0.2 wt%, the R-1 pressure drop was 0.11MPa and the R-2 pressure drop was 0.20MPa at the start of the apparatus operation, the R-1 pressure drop was increased to 0.56MPa, the R-2 pressure drop was 0.25MPa and the reaction temperature of R2 was 404 ℃ after 8000h of the apparatus operation.

Comparative example 2

Comparative example 2 the process flow is the same as in example 4, but the catalyst grading scheme is different, the specific loading ratio is shown in table 2, and the reaction conditions are shown in table 3.

Comparative example 2A 8000h stability test was carried out, the properties of the feed and the liquid stream II were as shown in Table 5, the iron content in the liquid stream I was controlled to not more than 3. mu.g/g, the temperature rise rate in the pretreatment zone was the same as in example 4, and the sulfur content in the liquid stream II was controlled to not more than 0.2 wt%, the pressure drop R-1 was 0.06MPa and the pressure drop R-2 was 0.17MPa at the start of the apparatus operation, the pressure drop R-1 was increased to 0.47MPa and the pressure drop R-2 was increased to 0.62MPa after 8000h of the apparatus operation, and the reaction temperature R2 was 417 ℃.

As can be seen by comparison, after 8000h of operation, the pressure drop of R-2 in comparative example 2 is obviously higher than that of R-2 in example 4, and the reaction temperature of R-2 is also 12 ℃ higher than that of example 4, so that the system provided by the invention can effectively intercept iron-containing compounds in the pretreatment reaction zone, provide better raw materials for long-period operation treatment of the main reaction zone, and improve the operation economy of the whole system.

Examples 6 to 7

Examples 6 to 7 were provided with a pretreatment reaction zone in which a single fixed bed reactor was disposed, and a hydrogenation protectant and a hydrodemetallization agent were sequentially filled in the reactor from bottom to top, and the catalyst filling ratios were as shown in table 2. The hydrocarbon raw material, water and hydrogen-containing gas are mixed and then enter a fixed bed reactor, and are sequentially contacted with a hydrogenation protective agent and a first hydrogenation demetallization agent for reaction, and a reaction product is extracted from the top of the fixed bed reactor, enters a first gas-liquid separation zone and is separated into a gas phase material flow and a liquid phase material flow. The hydrogen content of the hydrogen-containing gas of example 6 was 50 vol%, and the hydrogen content of the hydrogen-containing gas of example 7 was 100 vol%. The reaction conditions are shown in Table 6, and the properties of the starting materials and the properties of the products are shown in Table 7.

As can be seen from the data in table 7, the pretreatment reaction zone removes a substantial portion of the iron from the hydrocarbon feedstock, effectively protecting the subsequent primary reaction zone.

Example 8

In this example, the same fixed bed hydrogenation system and catalyst loading ratio as in example 3 were used. The hydrocarbon raw material, water and first hydrogen-containing gas are mixed and then enter a first fixed bed reactor (R-1) to be sequentially contacted with a hydrogenation protective agent and a first hydrogenation demetallization agent for reaction, and a reaction product enters a first gas-liquid separation zone and then is separated into a gas phase material flow I and a liquid phase material flow I. And the liquid phase material flow I and the second hydrogen-containing gas are mixed and then enter a second fixed bed reactor (R-2), and are sequentially contacted with a second hydrodemetallization agent and a hydrodesulfurization agent for reaction, and the reaction effluent passes through a second gas-liquid separation zone to obtain a gas phase material flow II and a liquid phase material flow II. The hydrogen content of the first hydrogen-containing gas was 70 vol%, and the hydrogen content of the second hydrogen-containing gas was 100 vol%. The reaction conditions are shown in Table 6.

Example 8A 8000h stability test was conducted, wherein the properties of the feed and liquid phase stream II were as shown in Table 8, wherein the iron content in the liquid phase stream I was controlled to be not more than 3 μ g/g, the sulfur content in the liquid phase stream II was controlled to be not more than 0.2 wt%, the R-1 pressure drop was 0.10MPa and the R-2 pressure drop was 0.20MPa at the start of the system operation, the R-1 pressure drop was increased to 0.52MPa, the R-2 pressure drop was 0.30MPa and the reaction temperature of R-2 was 410 ℃ after 8000h of system operation.

The preferred method provided by the invention can improve the radial distribution of iron in catalyst particles, delay the pressure drop rise of a reactor in a low-pressure area and further effectively intercept iron-containing compounds by introducing water into the hydrocarbon raw material.

Example 9

In this example, the same fixed bed hydrogenation system and catalyst loading ratio as in example 4 were used. The reaction conditions are shown in Table 6.

Example 9 stability test for 8000h, raw material properties and liquid phase stream II properties are shown in Table 8, controlling the iron content in liquid phase stream I not more than 3 μ g/g, and controlling the sulfur content in liquid phase stream II not more than 0.2 wt%, when the apparatus starts to operate, the pressure drop R-1 is 0.10MPa, the pressure drop R-2 is 0.20MPa, when the apparatus operates for 8000h, the pressure drop R-1 is increased to 0.53MPa, the pressure drop R-2 is 0.29MPa, and the reaction temperature R-2 is 405 ℃.

TABLE 2

TABLE 3

TABLE 4

Item	Starting materials A	Example 1	Example 2
				Liquid phase stream I
Density (20 ℃ C.), g/cm³	0.9687	0.9474	0.9512
				Sulfur, wt.%	3.37	2.79	3.13
Metal content,. mu.g/g
				Nickel (II)	45.1	40.0	44.6
Vanadium oxide	19.6	16.4	18.4
				Iron	21.8	4.9	6.7

TABLE 5

TABLE 6

TABLE 7

Item	Starting materials A	Example 6	Example 7
				Liquid phase stream I
Density (20 ℃ C.), g/cm³	0.9687	0.9476	0.9515
				Sulfur, wt.%	3.37	2.77	3.10
Metal content,. mu.g/g
				Nickel (II)	45.1	40.1	44.8
Vanadium oxide	19.6	16.1	18.5
				Iron	21.8	4.6	6.4

TABLE 8

Item	Raw material B	Example 8	Example 9
				Liquid phase stream II
Density (20 ℃ C.), g/cm³	0.9734	0.9281	0.9268
				Sulfur, wt.%	1.75	0.20	0.20
Metal content,. mu.g/g
				Nickel (II)	38.5	7.9	7.1
Vanadium oxide	18.9	3.2	2.8
				Iron	16.4	1.0	0.9

Claims

1. A fixed bed hydrogenation system for hydrocarbon raw materials comprises a pretreatment reaction zone, a first gas-liquid separation zone, a main reaction zone and a second gas-liquid separation zone, wherein an inlet of the pretreatment reaction zone is communicated with a raw material feeding line, an outlet of the pretreatment reaction zone is communicated with an inlet of the first gas-liquid separation zone, the first gas-liquid separation zone is provided with a gas-phase material flow I outlet and a liquid-phase material flow I outlet, the liquid-phase material flow I outlet is communicated with an inlet of the main reaction zone, an outlet of the main reaction zone is communicated with an inlet of the second gas-liquid separation zone, and the second gas-liquid separation zone is provided with a gas-phase material flow II outlet and a liquid; set up at least one fixed bed reactor in the preliminary treatment reaction zone, pack at least one hydrogenation protective agent and at least one first hydrogenation demetallization agent in proper order along the commodity circulation direction in fixed bed reactor, wherein, the particle diameter of the first hydrogenation demetallization agent that packs at commodity circulation direction end position is not more than 1.3mm, set up at least one fixed bed reactor in the main reaction zone, pack at least one second hydrogenation demetallization agent and at least one hydrodesulfurization agent in proper order along the commodity circulation direction in fixed bed reactor.

2. The system of claim 1, wherein the first hydrodemetallization agent is a combination of 2 to 4 first hydrodemetallization agents, the first hydrodemetallization agent has a gradually decreasing particle size along the flow direction, and the first hydrodemetallization agent is filled at the end of the flow direction to have a particle size of not more than 1.3 mm.

3. The system of claim 1 or 2, wherein the first hydrodemetallization agent is charged at the end portion in the direction of flow with a particle size of not more than 1.1 mm.

4. The system according to claim 1, wherein the hydrogenation protective agent comprises a carrier and an active component loaded on the carrier, the carrier is one or more selected from alumina, silica and titanium oxide, the active component is selected from group VIB metals and/or group VIII metals, the weight of the hydrogenation protective agent is taken as a reference, the active component accounts for 0-12 wt% of the oxide, and the balance is the carrier.

5. The system of claim 4, wherein the hydro-protectant has a particle size of 3 to 50.0mm and an average pore size of 18 to 4000 nm.

6. The system of claim 1 or 2, wherein the first hydrodemetallization agent has an active metal component content that is greater than an active metal component content of the second hydrodemetallization agent.

7. The system of claim 6, wherein the first hydrodemetallization agent has an active metal component content of 0.1 to 10 wt.% more than the active metal component content of the second hydrodemetallization agent.

8. The system according to claim 1 or 6, wherein the first hydrodemetallization agent comprises a carrier and an active component loaded on the carrier, the carrier is one or more selected from alumina, silica and titania, the active component is selected from a group VIB metal and/or a group VIII metal, the active component accounts for 3-30 wt% of the oxide based on the weight of the first hydrodemetallization agent, and the balance is the carrier.

9. The system of claim 8, wherein the first hydrodemetallization agent has a particle size of 0.8 to 3mm and an average pore size of 10 to 30 nm.

10. The system according to claim 1 or 6, wherein the second hydrodemetallization agent comprises a carrier and an active component loaded on the carrier, the carrier is one or more selected from alumina, silica and titania, the active component is selected from a group VIB metal and/or a group VIII metal, the active component accounts for 2.9-20 wt% of the oxide based on the weight of the second hydrodemetallization agent, and the balance is the carrier.

11. The system of claim 10, wherein the second hydrodemetallization agent has a particle size of 0.8 to 3mm and an average pore size of 9.9 to 29.9 nm.

12. The system according to claim 1 or 2, wherein the hydrodesulfurization agent comprises a carrier and an active component loaded on the carrier, the carrier is one or more selected from alumina, silica and titanium oxide, the active component is selected from group VIB metals and/or group VIII metals, the weight of the active component is 5-35 wt% calculated by oxides based on the weight of the hydrodesulfurization agent, and the balance is the carrier.

13. The system of claim 12, wherein the hydrodesulfurization agent has a particle size of 0.6 to 2mm and an average pore size of 7 to 15 nm.

14. The system of claim 1, wherein the loading volume fraction of the hydrogenation protective agent is 20-95% and the loading volume fraction of the first hydrodemetallization agent is 5-80% based on the pretreatment reaction zone monolithic catalyst.

15. The system of claim 1 or 2, wherein the loading volume fraction of the hydrogenation protective agent is 20-95% and the loading volume fraction of the first hydrodemetallization agent is 5-80%, based on the pretreatment reaction zone monolithic catalyst, and wherein the loading volume fraction of the first hydrodemetallization agent with a particle size of not more than 1.3mm is 5-70%.

16. The system of claim 3, wherein the loading volume fraction of the hydrogenation protective agent is 20-95% and the loading volume fraction of the first hydrodemetallization agent is 5-80%, based on the pretreatment reaction zone monolithic catalyst, and wherein the loading volume fraction of the first hydrodemetallization agent having a particle size of not greater than 1.1mm is 5-70%.

17. The system of claim 1, wherein the packed volume fraction of the second hydrodemetallization agent is 5-70% and the packed volume fraction of the hydrodesulfurization agent is 30-95% based on the total catalyst in the main reaction zone.

18. The system of claim 1, wherein 2-4 fixed bed reactors are arranged in parallel in the pretreatment reaction zone.

19. A method according to any one of claims 1 to 18, wherein the hydrocarbon feedstock is mixed with a first hydrogen-containing gas and then fed into a pretreatment reaction zone, and is sequentially contacted with a hydrogenation protecting agent and a first hydrodemetallization agent to react, the reaction product is fed into a first gas-liquid separation zone and then separated into a gas phase material flow I and a liquid phase material flow I, the liquid phase material flow I is fed into a main reaction zone and is sequentially contacted with a second hydrodemetallization agent and a hydrodesulfurization agent to react in the presence of a second hydrogen-containing gas, the reaction product is fed into a second gas-liquid separation zone and then separated into a gas phase material flow II and a liquid phase material flow II, and the hydrogen partial pressure in the pretreatment reaction zone is 0.1 MPa-4.0 MPa.

20. The process of claim 19, wherein the iron content of the hydrocarbon feedstock is greater than 8 μ g/g.

21. The method of claim 20, wherein the hydrocarbon feedstock is selected from one or more of diesel oil, wax oil, long residue, short residue, deasphalted oil, coal tar, and heavy coal-to-liquid oil.

22. The method of claim 19, wherein the hydrogen content of the first hydrogen-containing gas is 20% to 100% by volume.

23. The method of claim 22, wherein the hydrogen content of the first hydrogen containing gas is between 40% and 80% by volume.

24. The method of claim 19, wherein the reaction temperature of the pretreatment reaction zone is 100-400 ℃, and the liquid hourly space velocity is 0.10-10.0 h^-1The volume ratio of hydrogen to oil is 10-500.

25. The method of claim 19, wherein the reaction temperature of the main reaction zone is 300-460 ℃, the reaction pressure is 6-25 MPa, and the liquid hourly space velocity is 0.1-1 h^-1The volume ratio of hydrogen to oil is 250-1500.

26. The process of claim 19, wherein the hydrocarbon feedstock is admixed with water and passed together into the pretreatment reaction zone in a ratio of hydrocarbon feedstock to water of 100: 1 to 20.

27. The process of claim 26, wherein the ratio of hydrocarbon feedstock to water is 100: 2 to 15.

28. The process of claim 19, wherein the hydrocarbon feedstock is admixed with the oxygen-enriched hydrocarbon feedstock and passed together into the pretreatment reaction zone in a ratio of 100: 1-30 percent of oxygen-enriched hydrocarbon raw material, wherein the oxygen content of the oxygen-enriched hydrocarbon raw material is 1-20 percent based on the weight of the oxygen-enriched hydrocarbon raw material.