CN112795401B

CN112795401B - Hydrocracking method for treating high-nitrogen inferior raw material

Info

Publication number: CN112795401B
Application number: CN201911030753.6A
Authority: CN
Inventors: 范思强; 王仲义; 庞宏; 彭冲; 曹正凯; 崔哲; 孙士可; 吴子明
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2019-10-28
Filing date: 2019-10-28
Publication date: 2022-08-12
Anticipated expiration: 2039-10-28
Also published as: CN112795401A

Abstract

The invention discloses a hydrocracking method for processing high-nitrogen inferior raw materials, which comprises the following steps: mixing the raw material with high nitrogen content and hydrogen, then feeding the mixture into a hydrofining reaction zone to carry out hydrofining reaction, feeding the effluent of the hydrofining reaction zone into a hydrocracking reaction zone to carry out hydrocracking reaction, and then separating the effluent to obtain various products; the hydrofining reaction zone is at least provided with three catalyst bed layers. The method can effectively treat the raw material with high nitrogen content.

Description

Hydrocracking method for treating high-nitrogen inferior raw material

Technical Field

The invention relates to a hydrocracking method for processing high-nitrogen inferior raw materials, in particular to a hydrocracking method for efficiently processing high-nitrogen inferior raw materials.

Background

With the adjustment of international energy structure and the optimization of the process of a refinery enterprise, the hydrocracking process flow becomes an oil, chemical and fiber regulator because of the advantages of wide raw material source, excellent quality of cracked products, flexible operation, high liquid product yield and the like, the number of hydrocracking devices increases year by year, and the research on the hydrocracking process is paid extensive attention.

The hydrocracking process is divided into a first-stage process and a second-stage process, and the first-stage process is widely used. One section of the process is divided into two agents in one section and two agents in series in one section. The one-section two-agent process flow is simple, the equipment investment is low, but the defects of narrow raw material processing range, poor product quality and the like exist. The hydrocracking process is divided into a refining section and a cracking section by a series process, wherein the refining section aims to remove impurities such as sulfur, nitrogen, metal and the like in the raw materials through hydrogenation reaction and carry out hydrogenation saturation to a certain extent, so that the catalyst in the cracking section fully exerts activity, and the process has the advantages of good product quality, wide raw material source and flexible operation.

Along with the continuous aggravation of crude oil heaviness and the gradual aggravation of the economic pressure of refineries, crude oil is deeply drawn under reduced pressure and coal and shale oil resources are developed and utilized, so that the deterioration degree of hydrocracking raw materials is aggravated, particularly nitrogen impurities in the hydrocracking raw materials are difficult to remove and have obvious toxic action on catalysts in a cracking section. In response to the condition that the nitrogen content of the raw material with high nitrogen content fluctuates upwards, some refinery enterprises have to lower the space velocity of the refining section and increase the reaction temperature in actual production, the service life of the catalyst and the treatment capacity of the device are seriously influenced, and huge economic loss is brought.

CN1940030A discloses a hydrocracking method for producing diesel oil from high-nitrogen raw material, wherein high-nitrogen raw material oil is treated by a first hydrofining reactor, the generated oil enters a thermal flash tank for gas-liquid separation and then enters a second hydrofining reactor, and the dosage of hydrofining catalysts can be effectively reduced by processing high-nitrogen inferior raw materials under mild process conditions. The patent processes high-nitrogen raw materials by adding a refining reactor, greatly increases equipment investment and catalyst purchase cost, and has the defects of poor fixed flexibility of the process flow, insufficient utilization of the catalyst in the refining section, poor economic benefit and the like.

CN103102966A discloses a hydrocracking method for processing a high-nitrogen raw material, which adopts a two-stage process flow, the denitrification rate is controlled to be 60-95% after passing through a first-stage reaction zone, heavy tail oil enters a second reaction zone for further denitrification after gas-liquid separation of a first-stage reaction effluent, and the method can be operated under a relatively mild condition, and is beneficial to improving the running period of a hydrogenation device. The method is characterized in that a refining reactor is added to treat high-nitrogen raw materials, a separation system is added, and the activity of the catalyst is not fully exerted according to the regular characteristics of the refining reaction, so that the defects of narrow practical utilization range, high equipment investment, high catalyst purchasing cost and the like exist in the patent.

CN103773481A discloses a combined hydrocracking method for processing inferior raw materials, which adopts a countercurrent process to carry out pretreatment on high-nitrogen raw materials and adopts a cocurrent process to process conventional raw materials. The high-nitrogen raw material which can be treated by the method has the requirements on nitrogen content, and meanwhile, the method has the disadvantages of complex process, large equipment investment and poor economy. The nitrogen content of refined oil can not be optimized according to the concentration difference of different reaction zones, and the overall utilization rate of the catalyst at the refining section is not high.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a hydrocracking method for processing a high-nitrogen-content raw material. The method can effectively treat the raw material with high nitrogen content.

A hydrocracking method for processing high-nitrogen inferior raw materials comprises the following steps:

mixing the raw material with high nitrogen content and hydrogen, then feeding the mixture into a hydrofining reaction zone to carry out hydrofining reaction, feeding the effluent of the hydrofining reaction zone into a hydrocracking reaction zone to carry out hydrocracking reaction, and then separating the effluent to obtain various products;

the hydrofining reaction zone is at least provided with three catalyst beds which are sequentially marked as a first bed, a second bed and a third bed along the flow direction of material flow;

the catalysts filled in the first bed layer and the second bed layer take alumina as a carrier, and the catalyst filled in the third bed layer takes F and/or Mg modified alumina as a carrier;

The catalyst filled in the first bed layer takes Co and Mo as active metals, the pore volume of the catalyst is 0.40-0.50 mL/g, preferably 0.41-0.45 mL/g, and the content of the loaded metal active component in the catalyst is 15-20 wt%, preferably 18-20 wt%;

the catalyst filled in the second bed layer takes Ni and W as active metals, the pore volume of the catalyst is 0.01-0.08 mL/g lower than that of the hydrofining catalyst filled in the first bed layer, preferably 0.02-0.05 mL/g lower than that of the hydrofining catalyst filled in the first bed layer, and the content of the loaded active metals in the catalyst is 1-5 wt% higher than that of the catalyst filled in the first bed layer, preferably 2-3 wt% higher than that of the catalyst filled in the first bed layer;

the catalyst filled in the third bed layer takes Ni-W, Ni-Mo as an active metal, the pore volume of the catalyst is 0.01-0.05 mL/g lower than that of the catalyst filled in the second bed layer, preferably 0.02-0.03 mL/g lower than that of the catalyst filled in the second bed layer, the content of the loaded active metal in the catalyst is 1-8 wt% higher than that of the catalyst filled in the second bed layer, preferably 2-5 wt%, and the content of F and/or Mg is 1-5 wt% and preferably 2-3 wt%;

the filling volume of the catalyst of the first bed layer, the second bed layer and the third bed layer accounts for 1-25% of the volume of the hydrofining reaction zone: 8% -50%: 30% -90%, preferably 5% -10%: 15% -40%: 50% -80%.

In the method, the high-nitrogen-content raw material is generally a heavy fraction with nitrogen content of more than 1500 μ g, the nitrogen content is preferably 1800-3000 μ g, the sulfur content is not limited, the initial boiling point of the high-nitrogen-content raw material oil is generally 270-330 ℃, the final boiling point is generally 460-560 ℃, and the high-nitrogen-content raw material oil is one or more selected from deep-drawing vacuum wax oil, coking gas oil, deasphalted oil, coal tar and coal liquefied oil.

In the above process, the operating conditions in the hydrorefining reaction zone are as follows: the hydrogen partial pressure is 6-20 MPa, and preferably 8-16 MPa; the volume ratio of the hydrogen to the oil is 400-4000, preferably 600-1600; the volume airspeed is 0.1-5 h ^-1 Preferably 0.5 to 1.5 hours ^-1 (ii) a The average reaction temperature is 280-425 ℃, preferably 310-410 ℃.

In the method, part of the effluent of the hydrofining reaction zone is circulated to the second bed layer of the refining reactor, and the circulation amount is 5-80% (relative to fresh feed), preferably 20-50% (relative to fresh feed). And part of the effluent of the hydrofining reaction zone is circulated to the second bed layer, so that the adsorption competition relationship of the materials can be coordinated, and the denitrification effect is improved.

In the method, the operating conditions of the hydrocracking reaction zone are generally 5-20 MPa of hydrogen partial pressure, preferably 8-17 MPa; the volume ratio of the hydrogen to the oil is 400-4000, preferably 600-2000; the volume airspeed is 0.1-10 h ^-1 Preferably 0.5 to 2 hours ^-1 (ii) a The reaction temperature is 250-500 ℃, preferably 320-410 ℃.

In the above method, the catalyst used in the hydrocracking reaction includes a cracking component and a hydrogenation component. The cracking component typically comprises amorphous silica alumina and molecular sieve. The hydrogenation component is one or more of non-noble metal elements in VI group, VII group or VIII group, preferably two or more metals of Co, Mo, Ni and W are used as active components. The weight of the catalyst is taken as a reference, and the content of the hydrogenation component is 10-40% calculated by oxide. The catalyst can be any commercial hydrocracking catalyst, different types of hydrocracking catalysts are selected according to different target products, light oil type hydrocracking catalysts can be selected for naphtha, medium oil type hydrocracking catalysts can be selected for medium distillate, and flexible hydrocracking catalysts can be selected for flexible production of naphtha and medium distillate. For example, commercial hydrocracking catalysts such as FC-34, FC-50, FC-52 and FC-76 developed by the Fushun petrochemical research institute (FRIPP) can also be prepared according to the common knowledge in the art as required.

In the prior art, in order to realize the deep nitrogen removal of the high-nitrogen raw material, operation means such as reducing the feeding amount and increasing the reaction temperature are generally adopted, which can influence the economic benefit of the device or influence the service life of the catalyst.

Drawings

FIG. 1 is a schematic flow diagram of a hydrocracking process for treating high nitrogen poor feedstocks.

Wherein: 1 is raw material, 2 is a hydrofining reactor, 3 is partial refined effluent, 4 is the rest refined effluent, 5 is a hydrocracking reactor, 6 is hydrocracking reaction effluent, 7 is a separator, 8 is a gas product, 9 is a liquid product, 10 is naphtha, 11 is aviation kerosene, 12 is diesel oil, 13 is tail oil, 14 is hydrogen, 15 is recycle hydrogen, 16 is a compressor, 17 is a first bed layer, 18 is a first bed layer, and 19 is a first bed layer.

Detailed Description

The action and effect of the method of the present invention will be further described with reference to the drawings and examples, but the following examples are not to be construed as limiting the method of the present invention.

The method comprises the steps that a raw material 1 with high nitrogen content and hydrogen are mixed and then enter a hydrofining reactor 2, the mixture sequentially passes through a first bed layer 17, a second bed layer 18 and a third bed layer 19 and then flows out of the hydrofining reactor 2, part of refined effluent 3 circulates back to a feed inlet at the upper part of the second bed layer 18 and enters the hydrofining reactor 2 again, the rest of refined effluent 4 enters a hydrocracking reactor 5 for hydrocracking reaction, the obtained hydrocracking reaction effluent 6 enters a separator 7 for gas-liquid separation, a gas product 8 is recycled through a recycle compressor, and a liquid product 9 enters a fractionating tower 20 to obtain

corresponding hydrocracking products

10, 11, 12 and 13.

Example 1

The poor-quality high-nitrogen raw material is taken as a hydrocracking raw material, the properties of the oil product are shown in table 1, the process flow shown in the attached drawing is adopted, a first bed layer of a refining reactor is filled with a hydrofining catalyst A-1, the pore volume of the hydrofining catalyst A-1 is 0.45mL/g, and the loading amounts of Co metal oxide and Mo metal oxide which form the hydrofining catalyst A-1 are respectively 2.56 percent and 17.4 percent (the total loading amount of metal is 19.96 percent); the second bed layer is filled with a hydrofining catalyst B-1, the pore volume of the hydrofining catalyst B-1 is 0.40mL/g, and the load capacity of the formed Ni metal oxide and W metal oxide is 3.01 percent and 19.2 percent respectively (the total load capacity of the metals is 22.21 percent); the third bed layer is filled with a hydrofining catalyst C-1, the pore volume of the hydrofining catalyst C-1 is 0.37mL/g, the load amounts of the formed Ni metal oxide and W metal oxide are respectively 3.31 percent and 22.7 percent (the total load amount of metals is 26.01 percent), and the content of the carrier modified substance F is 2.12 percent. The total loading of the hydrofining catalyst is 120ml, and the hydrofining catalyst A-1: hydrofining catalyst B-1: the volume loading ratio of the hydrofining catalyst C-1 is 15:35:50, and the cracking reactor is loaded with FC-76 catalyst (120 ml). The refined oil circulation amount is 20% of the fresh feed, and other process conditions and experimental results are shown in tables 2 and 3.

TABLE 1

Example 2

The poor-quality high-nitrogen raw material is taken as a hydrocracking raw material, the properties of the oil product are shown in table 1, the process flow shown in the attached drawing is adopted, a first bed layer of a refining reactor is filled with a hydrofining catalyst A-2, the pore volume of the hydrofining catalyst A-2 is 0.41mL/g, and the loading amounts of Co metal oxide and Mo metal oxide which form the hydrofining catalyst A-2 are respectively 2.23 percent and 16.02 percent (the total loading amount of metal is 18.25 percent); the second bed layer is filled with a hydrofining catalyst B-2, the pore volume of the hydrofining catalyst B-2 is 0.37mL/g, and the load capacity of the formed Ni metal oxide and W metal oxide is respectively 2.51 percent and 17.9 percent (the total load capacity of the metals is 20.41 percent); the third bed layer is filled with hydrofining catalyst C-2, the pore volume of the hydrofining catalyst C-2 is 0.35mL/g, the load amounts of the formed Ni metal oxide and the Mo metal oxide are 3.03 percent and 20.1 percent respectively (the total load amount of metal is 23.13 percent), and the content of the carrier modified substance Mg is 2.86 percent. The total loading of the hydrofining catalyst is 120ml, and the hydrofining catalyst A-2: hydrofining catalyst B-2: the volume loading ratio of the hydrofining catalyst C-2 is 10:25:65, and the cracking reactor is loaded with FC-76 catalyst (120 ml). The refined oil circulation amount is 30% of the fresh feed, and other process conditions and experimental results are shown in tables 2 and 3.

Example 3

The poor-quality high-nitrogen raw material is taken as a hydrocracking raw material, the properties of the oil product are shown in table 1, the process flow shown in the attached drawing is adopted, a first bed layer of a refining reactor is filled with a hydrofining catalyst A-3, the pore volume of the hydrofining catalyst A-3 is 0.43mL/g, and the loading amounts of Co metal oxide and Mo metal oxide which form the hydrofining catalyst A-3 are respectively 3.23 percent and 16.55 percent (the total loading amount of metal is 19.78 percent); the second bed layer is filled with a hydrofining catalyst B-3, the pore volume of the hydrofining catalyst B-3 is 0.39mL/g, and the load capacity of the formed Ni metal oxide and W metal oxide is 3.51 percent and 18.29 percent respectively (the total load capacity of the metals is 21.8 percent); the third bed layer is filled with hydrofining catalyst C-3, the pore volume of the hydrofining catalyst C-3 is 0.37mL/g, the load amounts of the formed Ni metal oxide and W metal oxide are 3.63 percent and 22.1 percent respectively (the total load amount of metal is 25.73 percent), and the content of carrier modified substance F is 2.77 percent. The total loading of the hydrofining catalyst is 120ml, and the hydrofining catalyst A-3: hydrofining catalyst B-3: the volume loading ratio of the hydrofining catalyst C-3 is 10:45:45, and the cracking reactor is loaded with FC-76 catalyst (120 ml). The refined oil circulation amount is 50% of the fresh feed, and other process conditions and experimental results are shown in tables 2 and 3.

Example 4

The poor-quality high-nitrogen raw material is taken as a hydrocracking raw material, the properties of the oil product are shown in table 1, the process flow shown in the attached drawing is adopted, a first bed layer of a refining reactor is filled with a hydrofining catalyst A-3, the pore volume of the hydrofining catalyst A-3 is 0.43mL/g, and the loading amounts of Co metal oxide and Mo metal oxide which form the hydrofining catalyst A-3 are respectively 3.23 percent and 16.55 percent (the total loading amount of metal is 19.78 percent); the second bed layer is filled with a hydrofining catalyst B-3, the pore volume of the hydrofining catalyst B-3 is 0.39mL/g, and the load capacity of the formed Ni metal oxide and W metal oxide is 3.51 percent and 18.29 percent respectively (the total load capacity of the metal is 21.8 percent); the third bed layer is filled with hydrofining catalyst C-3, the pore volume of the hydrofining catalyst C-3 is 0.37mL/g, the load amounts of the formed Ni metal oxide and W metal oxide are 3.63 percent and 22.1 percent respectively (the total load amount of metals is 25.73 percent), and the content of the carrier modified substance F is 2.77 percent. The total loading of the hydrofining catalyst is 120ml, and the hydrofining catalyst A-3: hydrofining catalyst B-3: the volume loading ratio of the hydrofining catalyst C-3 is 10:45:45, and the cracking reactor is loaded with FC-76 catalyst (120 ml). Refined oil was not recycled and other process conditions and experimental results are listed in tables 2 and 3.

Comparative example 1

The poor-quality high-nitrogen raw material is used as a hydrocracking raw material, the properties of the oil product are shown in table 1, a conventional single-stage series process flow is adopted, only an industrial hydrofining catalyst FF-36 (120 mL) is filled in a refining reactor, the pore volume is 0.35mL/g, the loading amounts of a Ni metal oxide and a Mo metal oxide which form the catalyst are respectively 3.87 percent and 24.1 percent (the total loading amount of the metal is 27.97 percent), and an FC-76 catalyst (120 mL) is filled in a cracking reactor. The process conditions and experimental results are shown in tables 2 and 3.

Comparative example 2

The poor-quality high-nitrogen raw material is used as a hydrocracking raw material, the properties of the oil product are shown in table 1, a conventional single-stage series process flow is adopted, a refining reactor is only filled with a hydrofining catalyst C-4 (120 mL), the pore volume of the hydrofining catalyst C-4 is 0.38mL/g, the loading amounts of Ni metal oxide and W metal oxide which form the hydrofining catalyst are respectively 3.71 percent and 22.3 percent (the total loading amount of metal is 26.01 percent), and the content of a carrier modified substance F is 2.21 percent. The cracking reactor was packed with FC-76 catalyst (120 ml). The process conditions and experimental results are shown in tables 2 and 3.

Comparative example 3

The inferior high-nitrogen raw material is used as a hydrocracking raw material, the properties of the oil product are shown in table 1, a two-stage refining process is adopted, the raw oil firstly enters a first hydrofining reactor, the reaction distillate is subjected to flash evaporation treatment, the liquid phase distillate and hydrogen are mixed and enter a second hydrofining reactor, and then the second hydrofining reactor is connected with a conventional hydrocracking reactor and a separation process. The first and second hydrorefining reactors were each charged with 60mL of FF-36 catalyst having a pore volume of 0.35mL/g and composed of 3.87% and 24.1% of Ni metal oxide and Mo metal oxide (total metal loading of 27.97%), respectively, and the cracking reactor was charged with FC-76 catalyst (120 mL). The process conditions and experimental results are shown in tables 2 and 3.

TABLE 2 hydrocracking Main Process conditions

TABLE 3 hydrocracking Main product distribution and quality

The above examples show that in the hydrocracking process of the method, the hydrofining effluent part is circulated to the upper part of the second bed layer of the refining reactor and enters the refining reactor, the reaction activity of the refining catalyst is fully exerted when the hydrocracking raw material with high nitrogen content is treated, and when the nitrogen content of the refined oil is controlled to be lower than 10 mu g.g ^-1 The temperature of the refining reactor is obviously lower than that of the prior art, which is beneficial to prolonging the service life of the catalyst, simultaneously improving the yield of the heavy naphtha and the product properties of the aviation kerosene, diesel oil and tail oil, and bringing remarkable economic benefit for refineries.

Claims

1. A hydrocracking method for processing high-nitrogen inferior raw materials is characterized in that: the method comprises the following steps:

the catalyst filled in the first bed layer takes Co and Mo as active metals, the pore volume of the catalyst is 0.40-0.50 mL/g, and the content of the loaded metal active components in the catalyst is 15-20 wt%;

the catalyst filled in the second bed layer takes Ni and W as active metals, the pore volume of the catalyst is 0.01-0.08 mL/g lower than that of the hydrofining catalyst filled in the first bed layer, and the content of the loaded active metals in the catalyst is 1-5 wt% higher than that of the catalyst filled in the first bed layer;

the catalyst filled in the third bed layer takes Ni-W or Ni-Mo as active metal, the pore volume of the catalyst is 0.01-0.05 mL/g lower than that of the catalyst filled in the second bed layer, the content of the loaded active metal in the catalyst is 1-8 wt% higher than that of the catalyst filled in the second bed layer, and the content of F and/or Mg is 1-5 wt%;

the filling volumes of the catalysts of the first bed layer, the second bed layer and the third bed layer account for 1-25%, 8-50% and 30-90% of the volume fraction of the hydrofining reaction zone respectively;

part of the effluent of the hydrofining reaction zone is circulated to a second bed layer of the hydrofining reaction zone, and the circulation amount is 5-80%;

The operating conditions in the hydrofinishing reaction zone were as follows: hydrogen partial pressure is 6-20 MPa; the volume ratio of hydrogen to oil is 400-4000; the volume airspeed is 0.1-5 h ^-1 (ii) a The average reaction temperature is 280-425 ℃;

the operating conditions of the hydrocracking reaction zone are as follows: hydrogen partial pressure is 5-20 MPa; the volume ratio of hydrogen to oil is 400-4000; the volume airspeed is 0.1-10 h ^-1 (ii) a The reaction temperature is 250-500 ℃.

2. The method of claim 1, wherein: the catalyst filled in the first bed layer takes Co and Mo as active metals, the pore volume of the catalyst is 0.41-0.45 mL/g, and the content of the loaded metal active components in the catalyst is 18-20 wt%;

the catalyst filled in the second bed layer takes Ni and W as active metals, the pore volume of the catalyst is 0.02-0.05 mL/g lower than that of the hydrofining catalyst filled in the first bed layer, and the content of the loaded active metals in the catalyst is 2-3 wt% higher than that of the catalyst filled in the first bed layer;

the catalyst filled in the third bed layer takes Ni-W or Ni-Mo as active metal, the pore volume of the catalyst is 0.02-0.03 mL/g lower than that of the catalyst filled in the second bed layer, the content of the loaded active metal in the catalyst is 2-5% higher than that of the catalyst filled in the second bed layer, and the content of F and/or Mg is 2-3 wt%;

the filling volumes of the catalysts of the first bed layer, the second bed layer and the third bed layer account for 5-10%, 15-40% and 50-80% of the volume of the hydrofining reaction zone respectively.

3. The method of claim 1, wherein: the high nitrogen content raw material is heavy fraction with nitrogen content above 1500 mug/g.

4. The method of claim 1, wherein: the initial boiling point of the high-nitrogen content raw oil is 270-330 ℃, and the final boiling point is 460-560 ℃.

5. The method of claim 1, wherein: the operating conditions in the hydrofinishing reaction zone were as follows: the hydrogen partial pressure is 8-16 MPa; the volume ratio of the hydrogen to the oil is 600-1600; the volume space velocity is 0.5-1.5 h ^-1 (ii) a The average reaction temperature is 310-410 ℃.

6. The method of claim 1, wherein: and recycling part of the effluent of the hydrofining reaction zone to a second bed layer of the hydrofining reaction zone, wherein the recycling amount is 20-50%.

7. The method of claim 1, wherein: the operating conditions of the hydrocracking reaction zone are as follows: hydrogen partial pressure is 8-17 MPa; the volume ratio of the hydrogen to the oil is 600-2000; the volume airspeed is 0.5-2 h ^-1 (ii) a The reaction temperature is 320-410 ℃.

8. The method of claim 1, wherein: the catalyst adopted by the hydrocracking reaction comprises a cracking component and a hydrogenation component, wherein the hydrogenation component is selected from one or more of non-noble metal elements in VIB group, VIIB group or VIII group.