CN107723023B

CN107723023B - Delayed coking processing method of oil sand asphalt

Info

Publication number: CN107723023B
Application number: CN201610652555.3A
Authority: CN
Inventors: 张东明; 娄立娟; 张艳梅; 刘银东; 于志敏; 卢竟蔓; 许倩; 王丽涛; 张璐瑶; 侯经纬; 毕秦岭; 崔晨曦; 鄂宇恒
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2016-08-10
Filing date: 2016-08-10
Publication date: 2020-05-08
Anticipated expiration: 2036-08-10
Also published as: CN107723023A

Abstract

The invention discloses a delayed coking processing method of oil sand asphalt, which comprises the following steps: the method comprises the steps of carrying out a first coking reaction by taking asphalt oil as a raw material, heating the asphalt oil to 495-550 ℃, simultaneously carrying out a second coking reaction on the coking raw material except the asphalt oil in a residual oil heating furnace, mixing products of the first coking reaction and the second coking reaction to carry out a third coking reaction to generate a light product and coke, after the coking reactor is filled with the coke, feeding the raw material of the third coking reaction into another coking reactor, and discharging the coke remained in the original coking reactor by hydraulic decoking for recycling. The invention can improve the abrasion of fine sand particles contained in the raw material to the whole delayed coking unit and reduce the maintenance cost of the equipment. Meanwhile, the independent control of the heating temperature of the asphalt is realized, the coking trend of a furnace tube of the heating furnace is slowed down, and the yield of liquid products is improved.

Description

Delayed coking processing method of oil sand asphalt

Technical Field

The invention relates to a petroleum coking process, in particular to a delayed coking processing method of oil sand asphalt.

Background

Delayed coking is a residual oil conversion technology applied in a large number of oil refineries, is a main means for the lightening of residual oil in countries such as the United states, China, Venezuela, India, Canada and the like, more than 170 sets of residual oil delayed coking devices are operated all over the world, the total processing capacity is more than 4 hundred million tons, and the processing capacity of the delayed coking in 2012 of China reaches 1.13 hundred million tons.

The oil sand is a mixture of asphalt, water, sand and clay, wherein about 20% (mass fraction, the same applies below) of asphalt is contained, and part of heavy metals and sulfur are contained, so that the oil sand has high viscosity and cannot flow at normal temperature. The surface of each grit is covered by a thin layer of water, separating the grit from the outermost layer of asphalt.

And washing the mined oil sand with water to obtain the bitumen oil. Taking the property of the athabasca asphalt as an example, the athabasca asphalt has low API degree, high contents of sulfur, nitrogen and metals, and high requirements on equipment such as a hydrogenation device, a sulfur recovery system and the like during processing, so that most of upgrading plants in the area are built according to the property. Two schemes are generally adopted for processing the oil sand asphalt, wherein one scheme is that the oil sand asphalt is upgraded to synthetic crude oil and then is conveyed to a refinery for processing; another option is to dilute the bitumen by adding a diluent and pipeline it to a refinery with heavy oil processing conditions for subsequent processing. The general flow of the asphalt oil upgrading process is as follows: firstly, recovering the solvent for conveying the asphalt and returning the solvent to be recycled through a pipeline, wherein the process is usually carried out in an atmospheric tower; then, adopting an atmospheric and vacuum distillation process to extract about 10 percent of atmospheric distillate oil and 20 to 30 percent of vacuum distillate oil, and sending the atmospheric distillate oil and the vacuum distillate oil to a hydrofining device, a hydrotreating device and a hydrocracking device for modification treatment such as desulfurization, denitrification, dearomatization and the like; the atmospheric and vacuum residuum is usually treated by combined processes of coking, solvent deasphalting, etc. to make decarbonization and hydrogenation heavy oil light, so as to separate out light component and convert heavy component into refined product.

The predecessor of Suncor, Canada, Sun Oil Company (Sun Oil Company), was established in 1976, and was the first Oil sand mining and processing integrated Company in the world to produce synthetic Oil. The oil product produced by oil sand asphalt modification of the company has more particle content and cannot be transported by using a pipeline. In addition, the fine particles in the oil product are more and easy to block the aperture of the catalyst, which is not beneficial to the subsequent catalytic process, so that a processing device for further treatment needs to be established near the oil sand bitumen upgrading plant, for example, heavy oil is processed into a product which can be sent to the subsequent deep processing through processes such as delayed coking and the like.

The invention patent CN200810167107 provides a method and a device for directly coking an oil sand fluidized bed. The method comprises the following steps: the oil sand raw material is mixed with high-temperature sand from a dense-phase coking reactor in a coking reactor, the mixture is subjected to heat exchange and then is subjected to coking reaction, oil gas enters a fractionation and absorption stabilizing system after being dedusted, the attached tar sand is introduced into a dilute-phase coking pipe after being stripped by a stripper, the tar sand is coked in the dilute-phase coking pipe and the dense-phase coking reactor above the dilute-phase coking pipe, one strand of the coked hot sand is introduced into the coking reactor as a heat carrier, and the other strand of the coked hot sand is introduced into an external heat collector for heat exchange. If the coke production amount is low and the coke burning heat is insufficient, burning oil, coal powder or coke powder and the like can be introduced into the coke burning pipe to maintain the heat balance of the system. The device at least comprises: feeder, coking reactor, stripper, dilute phase coke-burning tube, dense phase coke-burning reactor, external heat collector and cyclone separator. The invention can directly process unconventional petroleum resources such as oil sand, oil shale and the like, has no pollution to the environment, and has strong continuous operability, large elasticity and high comprehensive utilization rate of system energy.

The delayed coking technology is characterized in that the coking oil (raw oil and circulating oil) is heated by a heating furnace and rapidly heated to the coking reaction temperature, no coke is generated in a reaction furnace tube, and the coking oil enters a coke tower for coking reaction, so that the delayed coking technology has a delayed effect.

Heating raw oil (vacuum residual oil or other heavy oil such as deoiled asphalt, clarified oil and even dirty oil) to 495-505 ℃, entering a coke tower, carrying out coking reaction on the hot raw oil in the coke tower, enabling the generated light product to come out from the top and enter a fractionating tower, and fractionating rich gas, crude gasoline, diesel oil and heavy distillate oil. The heavy fraction oil can be sent to further processing (such as catalytic cracking and hydrocracking raw materials) or can be totally or partially recycled to a raw oil system. After the coke is filled up (a certain space is reserved), the raw material is improved into another coke tower, and the residual coke in the coke tower is discharged by hydraulic decoking. The coke drum is returned to empty and then the hot feed is introduced.

The main equipment for delayed coking are furnaces and coke drums. Generally, the method is a semi-continuous process with one furnace (heating furnace) and two towers (coking towers) or two furnaces and four towers, wherein the heating furnace is continuously fed, and the coking towers are alternately operated. The quality of the operation state of the heating furnace and the length of the period determine the yield of the coking liquid product, the start-up period of the device and the maintenance cost of the equipment. Ultimately affecting the economics of the delayed coker.

The existing delayed coking process of blended asphalt oil has the following problems: (1) asphalt and residual oil are heated together, the heating temperature is limited by the coking temperature of the residual oil, and the asphalt is easy to coke in the furnace tube of the heating furnace to influence the heat transfer of the furnace tube and the operation period of the heating furnace; (2) the asphalt contains a large amount of fine sand particles, which can promote the coking of residual oil. Meanwhile, the fine sand particles with high hardness are easy to abrade key equipment such as a feed pump of the heating furnace, a heat exchanger, a heating furnace tube and the like, and the maintenance cost of the equipment is increased.

Disclosure of Invention

In order to solve the defects in the prior art, the invention aims to provide a delayed coking processing method for oil sand bitumen, which can improve the abrasion of fine sand particles contained in the raw material to a delayed coking whole device and reduce the maintenance cost of equipment. Meanwhile, the heating temperature of the asphalt is independently controlled, the coking trend of a furnace tube of the heating furnace is slowed down, and the yield of liquid products is improved.

In order to achieve the above object, the present invention provides a delayed coking processing method for oil sand bitumen, comprising the following steps: the method comprises the steps of carrying out a first coking reaction by taking asphalt oil as a raw material, heating the asphalt oil to 490-550 ℃, simultaneously carrying out a second coking reaction on the coking raw material except the asphalt oil in a residual oil heating furnace, mixing products of the first coking reaction and the second coking reaction to carry out a third coking reaction to generate a light product and coke, after the coking reactor is filled with the coke, feeding the raw material of the third coking reaction into another coking reactor, and discharging the coke remained in the original coking reactor by hydraulic decoking for recycling.

The delayed coking processing method of oil sand asphalt provided by the invention is characterized in that the reaction system of the first coking reaction is composed of an asphalt raw material tank, an asphalt feeding pump and an asphalt heating furnace which are connected in sequence.

The delayed coking processing method of oil sand asphalt provided by the invention is characterized in that preferably, the first coking reaction process is as follows: and (3) heating the asphalt oil to 90-120 ℃, conveying the asphalt oil to an asphalt raw material tank, and then feeding the asphalt oil into an asphalt heating furnace through an asphalt feeding pump, wherein the outlet temperature of the heating furnace is 490-550 ℃.

The delayed coking processing method of oil sand asphalt provided by the invention is characterized in that preferably, in the first coking reaction process: the outlet temperature of the heating furnace is 490-510 ℃.

The delayed coking processing method of oil sand asphalt provided by the invention is characterized in that the outlets of the asphalt heating furnace and the residual oil heating furnace are respectively provided with a ball valve, and the sealing surface of each ball valve is filled with low-pressure steam of 1.0-2.0 MPa.

The delayed coking processing method of the oil sand asphalt comprises the following steps of injecting 3.0-4.0MPa medium-pressure steam into a furnace tube of an asphalt heating furnace, and keeping the retention time of asphalt oil in the furnace tube of the asphalt heating furnace for 1.5-3 minutes.

The delayed coking processing method of the oil sand asphalt provided by the invention is characterized in that the blending proportion of the asphalt oil is preferably 1-20%.

The delayed coking processing method for oil sand bitumen of the present invention is preferably that the coking feedstock other than bitumen oil is at least one selected from the group consisting of vacuum residue, deoiled bitumen, decant oil and dirty oil.

The delayed coking processing method of the oil sand asphalt, provided by the invention, is characterized in that preferably, the light product is fractionated to obtain rich gas, crude gasoline, diesel oil and heavy fraction oil, and all or part of the heavy fraction oil is used as a coking raw material.

The delayed coking processing method of the oil sand asphalt provided by the invention is characterized in that the heavy fraction oil is preferably not used as part of a coking raw material and enters a catalytic cracking process or a hydrocracking process.

The delayed coking processing method of oil sand asphalt provided by the invention is specifically described as follows: the produced oil sand is washed by water to obtain asphalt oil which is used as a raw material and is sent to an independently-arranged asphalt raw material tank, sending asphalt oil to an independently arranged asphalt oil heating furnace through an asphalt feeding pump at the bottom of the tank for a first coking reaction, carrying out a second coking reaction on other raw oil except the asphalt oil in a residual oil heating furnace, heating the asphalt oil to 495-505 ℃, mixing the asphalt oil with other raw oil to form mixed raw oil, sending the mixed raw oil into a coke tower for a third coking reaction, sending the generated light product out of the top into a fractionating tower, fractionating to obtain rich gas, crude gasoline, diesel oil and heavy distillate oil, sending the heavy distillate oil for further processing, or recycling all or part of the heavy distillate oil to a raw oil system, and after the coke is filled continuously, the mixed raw oil enters another coke tower, coke remained in the original coke tower is discharged by hydraulic decoking, and the original coke tower is reused after being recovered to be empty.

The first coking reaction is a delayed coking reaction, and the outlet of the asphalt heating furnace is connected with the outlet of the residual oil heating furnace.

Compared with the prior art, the invention can improve the abrasion of fine sand particles contained in the raw material to the whole delayed coking device and reduce the maintenance cost of the equipment. Meanwhile, the independent control of the heating temperature of the asphalt is realized, the coking trend of a furnace tube of the heating furnace is slowed down, and the yield of liquid products is improved.

Drawings

FIG. 1 is a schematic process flow diagram according to a preferred embodiment of the present invention;

wherein the reference numbers:

(1) and equipment:

1-residual oil raw material buffer tank, 2-residual oil heating furnace, 3-asphalt heating furnace, 4-asphalt raw material tank, 5-asphalt feeding pump, 6-coke tower, 7-fractionating tower, 8-residual oil feeding pump and 9-four-way valve;

(2) and logistics:

a-residual oil, b-asphalt oil, c-rich gas, d-crude gasoline, e-diesel oil, f-heavy distillate oil, g-high temperature asphalt oil, h-high temperature residual oil, i-mixed raw oil and j-high temperature oil gas.

Detailed Description

The following examples are intended to further illustrate the process of the present invention but should not be construed as limiting thereof.

Example 1

As shown in figure 1, the produced oil sand is washed by water to obtain asphalt oil b which is used as a raw material and is sent to an independently arranged asphalt raw material tank 4, the asphalt oil is sent to an independently arranged asphalt oil heating furnace 3 through an asphalt feeding pump 5 at the bottom of the tank to carry out a first coking reaction, and the temperature is heated to 495-505 ℃ to form high-temperature asphalt oil g.

And residual oil a enters a residual oil raw material buffer tank 1, enters a residual oil heating furnace 2 through a residual oil feeding pump 8 to carry out a second coking reaction, and is heated to 490 ℃ to form high-temperature residual oil h.

And mixing the high-temperature asphalt oil g and the high-temperature residual oil h to form mixed raw oil, wherein the blending proportion of the asphalt oil is 1%, entering a coke tower 6 through a four-way valve 9 to perform a third coking reaction at 490 ℃ for 10 hours, and generating a light product (high-temperature oil gas j) and coke. The light product comes out from the top of a coke tower 6 and enters a fractionating tower 7, rich gas (dry gas) c, crude gasoline d, diesel oil e and heavy distillate oil f (including light wax oil and heavy wax oil) are fractionated, all or part of the heavy distillate oil f is recycled to a raw oil system of residual oil, after coke is filled continuously, the mixed raw oil enters another coke tower, coke remained in the original coke tower is discharged by hydraulic decoking, and the original coke tower is reused after being recovered to be empty.

Example 2

As shown in figure 1, the produced oil sand is washed by water to obtain asphalt oil b which is used as a raw material and is sent to an independently arranged asphalt raw material tank 4, the asphalt oil b is sent to an independently arranged asphalt oil heating furnace 3 through an asphalt feeding pump 5 at the bottom of the tank to carry out a first coking reaction, and the asphalt oil b is heated to 500 ℃ to form high-temperature asphalt oil g.

And residual oil a enters a residual oil raw material buffer tank 1, enters a residual oil heating furnace 2 through a residual oil feeding pump 8 to carry out a second coking reaction, and is heated to 500 ℃ to form high-temperature residual oil h.

Mixing the high-temperature asphalt oil g and the high-temperature residual oil h to form mixed raw oil i, wherein the blending proportion of the high-temperature asphalt oil g is 10%, entering a coke tower 10 through a four-way valve 9 to perform a third coking reaction at 490 ℃ for 10 hours, and generating a light product (high-temperature oil gas j) and coke. And (3) a light product (high-temperature oil gas j) comes out from the top of the coke tower 6 and enters a fractionating tower 7, a fraction rich gas (dry gas) c, crude gasoline d, diesel oil e and heavy distillate oil (including light wax oil and heavy wax oil) f are distilled, all or part of the heavy distillate oil f is recycled to a raw oil system of residual oil, after coke is filled up successively, the mixed raw oil i enters another coke tower 6, coke remaining in the original coke tower is discharged by hydraulic decoking, and the original coke tower is reused after being recovered to be empty.

Example 3

As shown in figure 1, the produced oil sand is washed by water to obtain asphalt oil b which is used as a raw material and is sent to an independently arranged asphalt raw material tank 4, the asphalt oil b is sent to an independently arranged asphalt oil heating furnace 3 through an asphalt feeding pump 5 at the bottom of the tank to carry out a first coking reaction, and the temperature is heated to 505 ℃ to form high-temperature asphalt oil g.

And the residual oil enters a residual oil raw material buffer tank 1, enters a residual oil heating furnace 2 through a residual oil feeding pump 8 to carry out a second coking reaction, and is heated to 505 ℃ to form high-temperature residual oil h.

And mixing the high-temperature asphalt oil g and the high-temperature residual oil h to form mixed raw oil i, wherein the blending proportion of the high-temperature asphalt oil g is 20%, entering a coke tower 6 through a four-way valve 9 to perform a third coking reaction at 490 ℃ for 10 hours, and generating a light product (high-temperature oil gas j) and coke. And (3) a light product (high-temperature oil gas j) comes out from the top and enters a fractionating tower 7, a fractionation rich gas (dry gas) c, a crude gasoline d, diesel oil e and a heavy distillate oil (including light wax oil and heavy wax oil) f are fractionated, all or part of the heavy distillate oil f is recycled to a raw oil system, after coke is filled continuously, the mixed raw oil i enters another coke tower 6, coke remaining in the original coke tower is discharged by hydraulic decoking, and the original coke tower is reused after being recovered to be empty.

The material balance data for the above process are shown in table 1.

Comparative example 1

Asphalt oil obtained by washing mined oil sand is taken as a raw material, the mixing proportion of the asphalt oil is 10 percent, the asphalt oil and residual oil are mixed and sequentially enter a heating furnace and a coke tower for coking reaction, the temperature of the coking reaction is 500 ℃, the time is 3min, and light products (high-temperature oil gas) and coke are generated. The generated light product comes out from the top of the coke tower and enters a fractionating tower to fractionate rich gas, crude gasoline, diesel oil and heavy distillate oil (including light wax oil and heavy wax oil), wherein all or part of the heavy distillate oil is recycled to a raw oil system of residual oil, after coke is filled continuously, the mixed raw oil enters another coke tower, coke remained in the original coke tower is discharged by hydraulic decoking, and the original coke tower is reused after being recovered to be empty.

The material balance data for the above process are shown in table 1.

TABLE 1

In table 1, differences 1, 2 and 3 are differences between examples 1, 2 and 3, respectively, and comparative example 1. From the material balance data of table 1 it can be seen that: the embodiment of the invention can effectively slow down the coking rate of the furnace tube of the heating furnace; meanwhile, the yield of the liquid product is improved.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the invention be considered as within the following claims.

Claims

1. A delayed coking processing method of oil sand asphalt is characterized by comprising the following steps: carrying out a first coking reaction by taking asphalt oil as a raw material, heating the asphalt oil to 490-550 ℃, simultaneously carrying out a second coking reaction on the coking raw material except the asphalt oil in a residual oil heating furnace, then mixing products of the first coking reaction and the second coking reaction for carrying out a third coking reaction, wherein the mixing proportion of the asphalt oil is 1-20%, generating a light product and coke, after the coking reactor is filled with the coke, feeding the raw material of the third coking reaction into another coking reactor, and recycling the coke remained in the original coking reactor after hydraulic decoking and discharging;

the coking feedstock other than asphaltic oil is selected from at least one of the group consisting of vacuum residuum, deoiled asphalt, decant oil, and dirty oil.

2. The process for delayed coking processing of oil sand bitumen as claimed in claim 1, wherein the reaction system of the first coking reaction consists of a bitumen feedstock tank, a bitumen feed pump and a bitumen heating furnace connected in series.

3. The delayed coking process for oil sand bitumen of claim 2, wherein the first coking reaction process is: and (3) heating the asphalt oil to 90-120 ℃, conveying the asphalt oil to an asphalt raw material tank, and then feeding the asphalt oil into an asphalt heating furnace through an asphalt feeding pump, wherein the outlet temperature of the heating furnace is 490-550 ℃.

4. The process for delayed coking processing of oil sands bitumen of claim 3, wherein during the first coking reaction: the outlet temperature of the heating furnace is 490-510 ℃.

5. The delayed coking processing method for oil sand bitumen according to claim 2, characterized in that the outlets of the bitumen heating furnace and the residual oil heating furnace are provided with ball valves, and the sealing surfaces of the ball valves are injected with low-pressure steam of 1.0-2.0 MPa.

6. The delayed coking processing method for oil sand bitumen of claim 5, wherein 3.0-4.0MPa medium pressure steam is injected into the furnace tube of the bitumen heating furnace, and the retention time of bitumen oil in the furnace tube of the bitumen heating furnace is 1.5-3 minutes.

7. The process of delayed coking of oil sand bitumen as claimed in claim 1, wherein the light products are fractionated to obtain rich gas, naphtha, diesel and heavy fraction oil, the heavy fraction oil being used wholly or partly as coking feedstock.

8. The delayed coking process for oil sand bitumen of claim 7, wherein the heavy fraction oil does not enter the catalytic cracking process or the hydrocracking process as part of the coking feedstock.