WO2016176983A1

WO2016176983A1 - Hydrogenation process temperature control method, and design method therefor and use thereof

Info

Publication number: WO2016176983A1
Application number: PCT/CN2015/095205
Authority: WO
Inventors: 李苏安; 邓清宇; 王坤朋
Original assignee: 北京中科诚毅科技发展有限公司
Priority date: 2015-05-07
Filing date: 2015-11-20
Publication date: 2016-11-10
Also published as: CN104888666A; CN105441128A; CN105441128B

Abstract

A hydrogenation process temperature control method, and a design method therefor and a use thereof. The hydrogenation process temperature control method comprises injecting a coolant into a hydrogenation device in order to control the temperature, injection positions being respectively located at a pipe in front of a certain stage or multi-stage reactor, in a pipe in front of a certain stage or multi-stage separator, and/or on the certain stage or multi-stage separator. The coolant is conveyed via at least one cooling pipe, and the flow may be controlled. The temperature control method effectively prevents reactor temperature runaway and the formation of vortex flows, and also prevents the occurrence of coking within the separator, thereby improving the operational stability of the hydrogenation device.

Description

Temperature control method of hydrogenation process, design method and use thereof

Technical field

The invention relates to a multi-optimized temperature control method for a slurry bed hydrogenation device and a design method and application thereof. The hydrogenation device comprises a slurry bed hydrogenation reactor and a separation system, and belongs to the fields of petrochemical and coal chemical industry.

Background technique

In recent years, with the continuous increase of crude oil extraction and the continuous reduction of conventional crude oil reserves, the trend of deteriorating crude oil is becoming more and more serious. The middle distillate obtained by direct distillation of crude oil and the middle distillate obtained by secondary processing such as coking and catalytic cracking are among the middle distillates. The S and N contents also increase accordingly. However, the demand for light oil in the market is increasing, and people's awareness of environmental protection is also increasing. Environmental laws and regulations are stricter on engine exhaust emissions, and various fuel standards require S and N to be more demanding. Therefore, how to process middle distillates with high impurities such as sulfur and nitrogen into products meeting environmental protection requirements is an important problem faced by various refineries. In this realistic environment, heavy oil hydrogenation, direct coal liquefaction and oil-coal mixing technology have been paid attention to. These technologies use a slurry-bed hydrogenation reactor to hydrocrack heavy hydrocarbon feedstock under the action of a catalyst, using a separation system. The reaction product was separated stepwise to give a light oil product.

The essence of the hydrocracking reaction process is high temperature, high pressure, hydrogen and strong exothermic catalytic hydrogenation. If the operation is improper, the flying temperature is easy to occur. The flying temperature means that the reactor is in an unstable operating state, when the operating parameters With small disturbances, the temperature in the local part of the reactor or in the entire reactor rises sharply and is out of control. If the temperature of the reactor exceeds 860 ° C, it will cause the catalyst to be deactivated or the internal components of the reactor will be damaged, which will lead to damage to the reactor wall and even a vicious accident of fire and explosion. When the temperature inside the separator rises, a large amount of polycondensation reaction occurs, causing serious coking and clogging, affecting the separation effect, and even causing the shutdown of the entire device. Therefore, how to strictly control the temperature of the hydrogenation equipment and keep the whole system in a stable state is an important task of engineering design and operation, if it is guaranteed or necessary to sacrifice the hydrogenation conversion rate, which is not only related to the operation of the reactor and the separation system. The stability and separation effect are related to the safe and stable operation of the entire plant and even the whole plant.

With regard to reactor temperature control methods, some literature and patents currently mention that all of the coolant is directly added to the reactor to lower the reactor temperature. However, adding the coolant directly to the reactor will destroy the reaction balance, causing different progress and density of the reaction in different parts of the reactor, thereby forming a vortex flow, which is not conducive to the reaction, and if the coolant is improperly selected, a side reaction may occur. On the one hand, a large amount of by-products are generated, which may corrode the entire system, and on the other hand, the operating parameters of the reaction system Changes are not conducive to the stability of the control system.

Regarding the temperature control method of the separation system, most of the current methods are to set a single-stage or two-stage separator. The separator only plays a role of flashing, and the material is cooled only by the heat exchanger and air cooling before entering the separator. It is easy to operate, and there are fewer openings on the separator, which reduces the possibility of leakage. However, the consequence of this is that once the temperature inside the separator rises, it cannot be reflected to the upstream temperature control system in time, causing a large amount of polycondensation reaction in the separator, causing serious coking and clogging, giving the entire device Suspension, even factory-wide shutdowns, caused great losses.

For slurry bed reactors in heavy oil hydrogenation, coal direct liquefaction and oil-coal mixing technology, due to the high content of S and N in heavy hydrocarbon feedstock, it is necessary to use two or more reactors in series to process heavy hydrocarbon feedstock. Fully hydrogenated; for the separation system, due to the complex material composition of the reactor outlet, it is impossible to completely separate the gas and liquid phases through a high-temperature high-pressure separator, and an organic combination of two or more separators is required, and the high-temperature high-pressure separator is directly connected to the reaction. The outlet of the device, and then step-by-step cooling and depressurization separate the gas-liquid products of different components one by one to achieve the desired separation effect.

Therefore, the present invention proposes an effective temperature control method for a slurry bed reactor and a separation system in a slurry bed reaction apparatus.

Summary of the invention

The invention provides a multi-optimized temperature control method for a slurry bed hydrogenation device, in which a cooling medium is driven into a pipeline between the reactors at various stages, so that the coolant and the reaction material are thoroughly mixed in the pipeline to form a uniform medium and then enter The next stage of the reactor, thereby reducing the temperature inside the reactor.

The technical solution of the invention:

A multi-optimized temperature control method for a hydrogenation unit in which a coolant is injected into a pipeline before a certain stage or multi-stage reactor inlet, the coolant being delivered through at least one cooling line and the flow rate being controllable.

The method also includes injecting a coolant into a conduit on a certain or multi-stage separator and/or a pre- or multi-stage separator inlet.

The coolant comprises cold hydrogen or cold oil or a mixture of the two, the cold hydrogen is recycled hydrogen, the purity is 85 vol% or more, and the temperature is 30-250 ° C; the cold oil is in the slurry bed reactor The circulating heavy oil produced has a temperature of 50-450 °C.

The cooling pipelines are 1-8, and each pipeline is provided with a temperature self-control valve and/or a hand valve and a temperature sensor.

The number of reactor stages is 2-3, and the number of stages of the separator is 2-6.

When the number of reactor stages is three, and the number of stages of the separator is six, the temperature before the inlet of the first stage reactor is controlled at 350-465 ° C, and the temperature between the first and second reactors is controlled at 380-480. °C, the temperature between the second and third reactors is controlled at 360-480 °C, the operating temperature of the high temperature and high pressure separator is controlled at 300-470 °C, the operating pressure is 17-22 MPa, and the reactor outlet material is shut off. The residence time is 0.5-60 minutes, and the subsequent separator operating temperature and operating pressure do not exceed the operating temperature and pressure of the high temperature and high pressure separator, and the residence time is 0.5-60 minutes.

Preferably, the reaction hydrogen is divided into two ways of heating, one way is heated in a hydrogen heating furnace, and all the way is mixed with the raw materials and then heated in the raw material heating furnace; then the hydrogen gas at the outlet of the hydrogen heating furnace is mixed with the reaction hydrogen and the raw materials. After mixing, the slurry enters the first-stage reactor, and is mixed with the stream of the first-stage reactor outlet to enter the secondary reactor, and is mixed with the stream of the secondary reactor outlet to enter the third-stage reactor. The reactor, all the way into the high temperature and high pressure separator.

An optimized temperature controlled slurry bed hydrogenation apparatus, wherein at least one cooling line is connected to a pipeline and/or a separator before a reactor of a certain stage or multiple stages and a separator inlet, in the cooling pipeline The coolant is cold hydrogen or cold oil or a mixture of the two, the amount of which is controllable.

The above-mentioned use of a multi-optimized temperature control method for a slurry bed hydroprocessing device for a heavy oil hydrogenation process, a coal direct liquefaction process, and a reactor and separator in a coal-oil mixing process, the heavy oil including heavy One or more combinations of crude oil, residual oil, catalytic oil slurry, deoiled asphalt, coal tar, the coal includes one or more combinations of lignite, bituminous coal, non-stick coal, and the oil-coal mixing process The ratio of medium oil to coal ranges from 97:3 to 30:70.

A multi-optimized temperature control design method for slurry bed hydrogenation equipment, in which a coolant is injected into a hydrogenation equipment to control temperature, and the injection position is respectively located in a pipeline before the inlet of a certain stage or multi-stage reactor, a certain stage or multiple stages of separation In the conduit in front of the inlet and/or on a stage or multistage separator, the coolant is delivered through at least one cooling line and the flow is controllable.

Technical effects of the present invention:

A multi-optimized temperature control method for a slurry bed hydrogenation apparatus of the present invention, in order to control the reactor temperature and maintain the stability of the reaction state in the reactor, a coolant is injected into the pipeline between the inlets of the reactor, so that the coolant The outlet material of the upper reactor is thoroughly mixed in the pipeline and then enters the next-stage reactor. Since the temperature of the reaction material is lowered, the temperature of the next-stage reactor is controlled within a reasonable range, and the reaction system in the reactor is ensured. Uniform density to avoid the formation of vortex flow. The temperature control method of the present invention, according to actual needs, when the temperature of a certain stage reactor or multi-stage reactor rises, the coolant is introduced into the pipeline before the corresponding reactor inlet, and multiple cooling is designed for each injection position. In the pipeline, the flow rate of each pipeline can be adjusted. According to the difference between the target temperature and the reactor temperature, the flow rate is adjusted to control the reactor to be in a safe temperature range. Therefore, the temperature control method of the invention is simple in operation, easy to implement in engineering implementation, prevents the formation of the separator from flying temperature and vortex flow, and greatly improves the operational stability of the hydrogenation equipment.

The temperature control method of the present invention further comprises introducing a coolant into the slurry bed separation system to control the temperature of the separator to minimize the polycondensation reaction in the separator, minimizing the possibility of coking, and improving liquid and solid. Separation efficiency, thereby increasing liquid yield and circulating hydrogen purity.

Circulating hydrogen or circulating heavy oil is an intermediate product of heavy oil hydrogenation, which is easy to obtain, low in cost, and also a reactant of hydrogenation reaction. It does not produce by-products in the reactor, and may occur as the reactants in the original reaction system. The reaction is also consistent, and does not change the operating parameters of the original reaction system, so that the stability of the entire hydrogenation system is easy to control.

A temperature control valve or a hand valve and a temperature sensor are arranged on each cooling pipe to improve the operability and safety of the temperature control and to facilitate automatic control.

The slurry bed hydrogenation system includes a 2-3 stage reactor and a 2-6 stage separator to achieve sufficient hydrogenation and separation to obtain more liquid oil. The method is particularly suitable for use in the reactor stage, and the reaction heat of the reactant of the upper stage can be fully utilized reasonably to achieve efficient use of heat while ensuring the stability of the next stage reactor. Since the reaction does not occur in the separator and is relatively stable, the method can be directly applied to the separator to quickly achieve the cooling effect.

For the temperature control of the first-stage reactor, the temperature can be controlled by injecting the coolant, or the temperature can be controlled by setting two channels of hydrogen separately heating and remixing. On the one hand, one way of hydrogen is separately heated to a higher temperature and mixed with a lower temperature mixture of the raw material heating furnace outlet, and the temperature of the primary reactor inlet is adjusted by controlling the mixing ratio; on the other hand, the higher temperature hydrogen is separately It is introduced into the inlet of the second-stage or third-stage reactor and the inlet of the high-temperature high-pressure separator to increase the partial pressure of hydrogen in the secondary or tertiary reactor and the separator, thereby solving the reaction of the multi-stage reactor due to insufficient hydrogen partial pressure. Insufficient problems and the problem that the separator has a polycondensation reaction due to high temperature and low partial pressure of hydrogen.

The method is particularly suitable for a slurry bed reactor and a separation system in a heavy oil hydrogenation process, a coal direct liquefaction process and a coal-oil mixing process which have a large solid content and cannot achieve temperature uniform control by the existing temperature control method. Since the hydrocracking reaction in the slurry bed reactor is a strong exothermic reaction and has strict requirements on the reaction temperature, it is necessary to accurately determine the reaction progress, heat release and temperature rise under different working conditions when designing the reactor. Calculations stabilize the operating temperature of the reactor by controlling the inlet temperature of the reactor. In addition, the slurry bed separation system is directly connected to the outlet of the reactor, and the temperature is high, and side reactions are likely to occur, which affects the separation effect. Therefore, the method fully considers the reaction characteristics of the slurry bed reactor and the separator, and efficiently controls the temperature in the slurry bed reactor and the separator to ensure long-term stable operation of the hydrogenation equipment and avoid safety accidents.

DRAWINGS

1 is a schematic view showing a slurry bed hydrogenation and a reaction scheme according to an embodiment of the present invention;

2 is a schematic view showing a temperature control method of a slurry bed reactor according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a temperature control method of a separation system according to an embodiment of the present invention.

The labels in the figure are listed as follows:

1-hydrogen high-gas heat exchanger; 2-hydrogen heating furnace; 3-feeding furnace; 4-stage reactor; 5-secondary reactor; 6-high temperature and high pressure separator; 7-supplement of hydrogen; Circulating hydrogen; 9-raw material; 10-hot high-scoring gas; 11-cold oil; 12-cold hydrogen; 13- Reaction product; 14-high temperature low pressure separator; 15-intermediate low pressure separator; 16-normal temperature and pressure separator; 17-medium temperature high pressure separator; 18-normal temperature high pressure separator; 19-demineralized water; 20-tail gas; Normal temperature oil; 22-waste water; 23-medium temperature oil; 24-high temperature oil.

detailed description

In order to further illustrate the specific features of the invention, the invention will be described in conjunction with the accompanying drawings.

This embodiment is a temperature control method for a slurry bed hydrogenation equipment involved in the oil coal mixing process, the hydrogenation reactor is a second stage, and the separator is 6 stages. The specific temperature control process is as follows:

As shown in FIG. 1, the hydrogenation and reaction process of the slurry bed reactor of the embodiment of the present invention firstly supplements the hydrogen gas 7 with the circulating hydrogen gas 8, and then the gas with the high temperature and high pressure separator 6 is the hot high gas 10 in the hydrogen gas. The heat exchange at the high gas heat exchanger 1 is raised to 425 ° C hydrogen. Then, 20% of the hydrogen is mixed with the coal slurry feed 9, and then enters the mixture flow of the raw material heating furnace 3 to 365 ° C, and 80% of the hydrogen enters the hydrogen heating furnace 2 to raise the temperature to 535 ° C of high temperature hydrogen. Then the high-temperature hydrogen is divided into three-way transportation: a part of the mixture and the mixture flow, the control feed temperature is 385 ° C, and the hydrogenation reaction occurs in the first-stage reactor 4; a part is mixed with the first-stage reactor outlet material and then enters the secondary reactor 5 to further occur. In the hydrogenation reaction, the hydrogen feed is 1/15 of the hydrogen feed of the first reactor; a portion enters the high temperature and high pressure separator 6 from the bottom.

2 is a schematic diagram of a temperature control method of a slurry bed reactor according to an embodiment of the present invention. When the temperature sensor detects that the reaction temperature of the secondary reactor 5 rises above a normal temperature range, it is to the first and second levels. The coolant is introduced into the pipeline between the reactors, and the cooling medium includes the circulating heavy oil produced in the oil-coal mixing process, the cold oil 11, the temperature is 225 ° C, two cooling pipes, and the circulating hydrogen - cold hydrogen 12, the purity is 95.5 vol%, the temperature is 55 ° C, delivered through 4 cooling lines, the flow rate is controlled by the automatic valve (supplement flow data) until the temperature in the secondary reactor is controlled within the range of 410-420 ° C, the valve is closed, and the valve is stopped. Inject coolant.

The reaction product 13 flowing out from the outlet of the secondary reactor enters the high-temperature high-pressure separator 6, the operating temperature is 420 ° C, and the operating pressure is 18.7 MPa. In order to keep the operating temperature stable, the cold oil 11 is driven by the temperature sensor. Or the flow rate of the cold hydrogen 12 stabilizes the temperature of the high-temperature high-pressure separator 6 at about 420 ° C. Specifically, as shown in FIG. 3 , the gas phase separated from the upper portion of the high-temperature high-pressure separator 6 is cooled, and then enters the intermediate-temperature high-pressure separator 17 . After the liquid level control valve is adjusted, it enters the high temperature and low pressure separator 14; the operating temperature of the medium temperature high pressure separator 17 is 285 ° C, the operating pressure is 18.6 MPa, and the gas phase separated from the upper portion enters the normal temperature high pressure separator after cooling, water injection and secondary cooling. The liquid phase is adjusted by the liquid level control valve and enters the medium temperature low pressure separator 15; the normal temperature high pressure separator 18 operates at a temperature of 55 ° C, the operating pressure is 18.5 MPa, and the gas phase separated from the upper portion is used as the circulating hydrogen 8 , and the normal temperature high pressure separator 18 The lower liquid phase is adjusted by the liquid level control valve to enter the normal temperature low pressure separator 16; the high temperature low pressure separator 14 operating temperature is 420 ° C, the operating pressure is 3.0 MPa, in order to operate The temperature is kept constant, and the flow rate of the cold oil 11 or the cold hydrogen 12 that is driven therein by the temperature sensor is controlled to stabilize the temperature of the high-temperature low-pressure separator 14. At about 420 °C (see Figure 3), the gas phase separated from the upper part is cooled and then enters the medium-temperature low-pressure separator 15. The liquid phase is adjusted by the liquid level control valve as a high-temperature oil 24 separator; the medium-temperature low-pressure separator 15 operating temperature It is 285 ° C, the operating pressure is 2.9 MPa, the upper gas phase is cooled and then enters the normal temperature low pressure separator 16 , the liquid phase is adjusted by the liquid level control valve as a medium temperature oil 23 out separator; the normal temperature low pressure separator operating temperature is 55 ° C, operation The pressure is 2.8 MPa, the upper gas phase is used as a tail gas 20 separator to enter the gas treatment device, and the lower liquid phase is used as a room temperature oil 21 separator, and the liquid collection bag contains ammonium bicarbonate and ammonium sulfide wastewater 22 to the wastewater treatment device.

In the actual operation, the temperature stability of the first-stage reactor 4 and the uniformity of the reactants are ensured in the actual operation, and the temperature in the secondary reactor 5, the reactant and hydrogen partial pressure, and the hydrogen content in the high-temperature high-pressure separator 6 are ensured. The pressure also remained stable and no coking occurred.

In addition to controlling the temperature of the first-stage reactor 4 by heating and conveying the hydrogen and the raw materials, a method of introducing a coolant into the pipeline before the inlet of the primary reactor 4 may be employed, but the controlled hydrogen heating of the present embodiment is employed. The method of controlling the inlet temperature of the primary reactor is a more preferred mode. If the number of reactor stages is three, the temperature control method of the three-stage reactor is the same as the temperature control method of the above two-stage reactor.

It can be seen from the above embodiment that using the multi-optimized slurry bed reaction equipment temperature control method of the present invention can ensure uniform temperature throughout the reactors at all stages, so that the entire reaction system is in a stable state; The operating temperature of the separator makes the separation system under a steady state operating condition, and for the gas phase, the purpose of reducing the operating pressure of the downstream device and ensuring the purity of the circulating hydrogen is achieved. It is to ensure the liquid yield and the separation effect is optimal.

The coolant used is recycled hydrogen and recycled heavy oil, which is the reaction intermediate and also the reaction raw material. The advantages of this are: (1) circulating hydrogen and recycled heavy oil are easily obtained; (2) no by-products are produced; The system operating parameters change little, so that the system is in a controllable state; (4) the use of two sources of media to control the temperature is more secure.

The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present invention. All should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Claims

A multi-optimized temperature control method for a hydrogenation unit, characterized in that a coolant is injected into a pipeline before a certain stage or multi-stage reactor inlet, and the coolant is conveyed through at least one cooling line and the flow rate is controllable.
The method of claim 1 further comprising injecting a coolant into the conduit before the inlet of the one or more stages and/or the inlet of the stage or stages of the separator.
The method according to claim 1 or 2, wherein the coolant comprises cold hydrogen or cold oil or a mixture of the two, the cold hydrogen is recycled hydrogen, the purity is 85 vol% or more, and the temperature is 30-250 ° C; The cold oil is a circulating heavy oil produced in the slurry bed reactor at a temperature of 50-450 °C.
The method according to claim 1 or 2, characterized in that the number of the cooling pipes is 1 to 8, and each of the pipes is provided with a temperature self-control valve and/or a hand valve and a temperature sensor.
The method of claim 2 wherein said reactor stages are 2-3 stages and said separator stages are 2-6 stages.
The method according to claim 5, characterized in that the number of reactor stages is three, the number of stages of the separator is six, and the temperature before the inlet of the first stage reactor is controlled at 350-465 ° C, one or two. The temperature between reactors is controlled at 380-480 °C, the temperature between the second and third reactors is controlled at 360-480 °C, the operating temperature of high temperature and high pressure separator is controlled at 300-470 °C, the operating pressure is 17-22 MPa, and the reactor outlet material is controlled. The residence time of the separation is 0.5-60 minutes, and the subsequent separator operating temperature and operating pressure do not exceed the operating temperature and pressure of the high-temperature high-pressure separator, and the residence time is 0.5-60 minutes.
The method according to claim 6, characterized in that the reaction hydrogen is divided into two ways of heating, one way is heated in a hydrogen heating furnace, and all the way is mixed with the raw materials and then heated in the raw material heating furnace; then the hydrogen gas at the outlet of the hydrogen heating furnace is all the way The reaction hydrogen is mixed with the raw material mixture and then enters the first-stage reactor, and is mixed with the stream of the first-stage reactor outlet to enter the secondary reactor, all the way to the secondary reactor outlet. After the stream is mixed, it enters the tertiary reactor and enters the high temperature and high pressure separator all the way.
An optimized temperature controlled slurry bed hydrogenation apparatus characterized in that at least one cooling line is connected to a pipeline and/or a separator before a reactor of a certain stage or multiple stages and a separator, the cooling pipe The coolant in the road is cold hydrogen or cold oil or a mixture of the two, the amount of which is controllable.
The use of a multi-optimized temperature control method for a slurry bed hydroprocessing apparatus according to claims 1-7, characterized by a reactor for use in a heavy oil hydrogenation process, a coal direct liquefaction process, and a coal-coal mixing process a separator, the heavy oil comprising one or more combinations of heavy crude oil, residual oil, catalytic oil slurry, deoiled asphalt, coal tar, the coal including one or more of lignite, bituminous coal, non-stick coal In combination, the ratio of oil to coal in the oil-coal mixing process ranges from 97:3 to 30:70.
A multi-optimized temperature control design method for slurry bed hydrogenation equipment, characterized in that a coolant is injected into a hydrogenation device to control temperature, and the injection position is respectively located in a pipeline before a certain stage or multi-stage reactor inlet, a certain stage or In the conduit in front of the inlet of the multistage separator and/or on a stage or multistage separator, the coolant is delivered through at least one cooling line and the flow is controllable.