CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. 201910900580.2, filed on Sep. 23, 2019, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a heavy oil upgrading technology, and in particular, to an integrated method and an integrated device for heavy oil contact lightening and coke gasification.

BACKGROUND

The heavy oil is a residue left after the crude oil is subjected to fractionation to extract gasoline, kerosene, and diesel; furthermore, there are also abundant heavy oil resources in strata. The heavy oil has the characteristics of, for example, heavy components and low hydrogen-carbon ratio, and usually has a relatively high content of sulfur, nitrogen, heavy metals and carbon residue value, etc. With the continuous development of crude oil, the problems of heavy and inferior quality of crude oil have become more and more serious, and environmental protection regulations are becoming stricter, so how to lighten the heavy oil, and convert the heavy oil into gasoline, diesel, liquefied gas and other qualified clean oil products are main challenges faced by petroleum processing enterprises at present.

At present, the processing route for lightening the heavy oil can be roughly divided into two types, hydrogenation and decarbonization. Among them, the hydrogenation is to increase the hydrogen-carbon ratio by the reaction of the heavy oil with hydrogen. The hydrogenation occupies an important position in the processing of the heavy oil, but due to high content of carbon residue value, heavy metal and heteroatom in the heavy oil, direct use of hydrocracking method often requires a large amount of hydrogen, and usually needs to be carried out under the conditions of high pressure and high efficient catalyst, the difficulty of implementing the process is relatively high. Additionally, since the heavy oil has a relatively low hydrogen-carbon ratio, the problem of lack of hydrogen in the process of obtaining clean oil products by lightening of the heavy oil is often more prominent.

Since the addition of external hydrogen resources is not involved, the decarbonization processing is generally a redistribution of carbon and hydrogen resources of raw materials in products. Currently, the commonly used decarbonization technologies at home and abroad mainly include a catalytic cracking process and a delayed coking process. Among them, the catalytic cracking process usually causes rapid carbon deposition on or toxic deactivation of the catalyst, and the amount of coke formation in the heavy oil catalytic cracking process is relatively large, and if a traditional coking method is used for catalyst regeneration, a large amount of external heat will be required, and at the same time, it will also be a great waste of carbon resources to a certain extent. During the delayed coking process, since no catalyst is involved, the delayed coking process has greater adaptability to raw materials. However, the delayed coking process produces a large amount of solid coke as a by-product, and the latest environmental protection requirements have taken measures to restrict the high-sulfur coke with a sulfur content of >3% from leaving from factory, thus the application of the delayed coking process is limited.

In view of the above advantages and disadvantages of the hydrogenation and the decarbonization, firstly cracking the heavy oil into light oils and then hydrotreating the light oils to obtain acceptable products has become a choice of many petroleum processing enterprises.

CN1504404A discloses a process method for combining oil refining and gasification. First, a petroleum hydrocarbon and a coke transfer agent contact and react with each other in a reactor, and the resulting oil gas enters a subsequent product separation system, the coke transfer agent deposited with carbon is transferred into a gasifier, and reacts with, for example, water vapor and oxygen-containing gas so as to produce a syngas, and achieve the regeneration of the coke transfer agent deposited with carbon. The regenerated coke transfer agent is returned into a cracking section for recycling. The present disclosure achieves a combination of two processes of oil refining and gasification, the process flow is similar to the catalytic cracking process, and the coke gasification process is used to replace the traditional coking regeneration process.

CN102234534A discloses a method for processing an inferior heavy oil, where the method firstly uses a contact agent with low activity to perform a cracking reaction of the heavy oil, the reacted contact agent deposited with carbon is transported to different reaction zones of the gasification section to perform combustion or gasification regeneration, to obtain a semi-regenerant and a secondary regenerant with different coke content, respectively; the multi-section regenerating reaction in the reactor increases the operation difficulty of the process to a certain extent.

CN102115675A discloses a processing method of heavy oil lightening and a device thereof. Firstly, the raw oil reacts with a solid heat carrier in a thermal cracking reactor to obtain a light oil gas product. The heavy coke is attached to a surface of the solid heat carrier and enters a combustion (gasification) reactor through a material returning valve to remove the coke on the surface, and the regenerated high-temperature solid heat carrier is partially returned to the thermal cracking reactor through a distribution valve, serving as a reaction bed material.

CN102965138A discloses a coupling process of pyrolysis and gasification for a heavy oil in a double-reaction-tube semi-coke circulating bed, which proposes the use of a descending reaction tube for cracking of the heavy oil to obtain a light oil gas product. The coked semi-coke enters the riser gasification reactor to perform a gasification reaction with an oxidant and water vapor, to produce a syngas; after the reaction, the high-temperature semi-coke flows into the material returning device and continues to circulate, so as to provide the heat required for the heavy oil reaction.

In the above methods, different types of reactors, such as a fluidized bed, a riser and a downer, are used for the cracking reaction of the heavy oil. However, generated heavy cokes need to be transported to another reactor for performing regeneration reaction such as gasification and combustion, so that materials have to be recycled and returned in multiple reactors, not only making the equipment occupy a larger area in practical production, but also having high energy consumption.

SUMMARY

In view of the above defects, the present disclosure provides an integrated method for heavy oil contact lightening and coke gasification, which can achieve mutual supply of materials and mutual complementation of heat in two reaction processes of the heavy oil cracking and the coke gasification, thereby reducing energy consumption in heavy oil processing and saving equipment occupied area.

The present disclosure further provides an integrated device for heavy oil contact lightening and coke gasification, the utilization of the integrated device for processing a heavy oil, can implement the aforementioned integrated method, thereby reducing energy consumption and saving equipment occupied area.

In order to achieve the above object, the present disclosure provides an integrated method for heavy oil contact lightening and coke gasification, the integrated method uses a coupled reactor as a reactor, the coupled reactor includes a cracking section at an upper part and a gasification section at a lower part, and the cracking section and the gasification section communicate with each other; the integrated method includes:

feeding a heavy oil material into the cracking section of the coupled reactor, so as to contact with a contact agent to implement a cracking reaction, to obtain a light oil gas and a carbon-deposited contact agent;

passing the carbon-deposited contact agent into the gasification section, so as to implement a gasification reaction with a gasification agent and regenerate the contact agent, to obtain a regenerated contact agent and a syngas; where the regenerated contact agent after being cooled by heat exchange is returned into the cracking section for recycling; and the syngas ascends into the cracking section;

discharging the light oil gas and the ascended and incorporated syngas from the cracking section, to perform a gas-solid separation, so that the carbon-deposited contact agent carried is separated and returned to the cracking section, and a purified oil gas is obtained at the same time.

In the integrated method for heavy oil contact lightening and coke gasification provided by the present disclosure, the heavy oil material enters into the cracking section at the upper part of the coupled reactor, and is cracked by contacting with the contact agent, and a decarbonization and upgrading reaction occurs, to obtain the light oil gas and the coke. The cokes adhere to a surface of the contact agent, to become the carbon-deposited contact agent. The carbon-deposited contact agent enters into the gasification section, so that the coke on the surface of the contact agent undergoes a gasification reaction with the gasification agent entered into the gasification section, to achieve the regeneration of the contact agent while obtaining a high-temperature syngas.

The high-temperature syngas ascends into the cracking section, which can not only provide heat required for the cracking reaction, but also the highly active hydrogen-rich syngas can further provide a hydrogen atmosphere for cracking of the heavy oil, so as to inhibit coking in the process of the heavy oil cracking and increase yield of the light oil gas to a certain extent. Furthermore, the syngas enters from a bottom of the cracking section and ascends to incorporate into the light oil gas, which can also ensure full fluidization of the contact agent i, and further increase the yield of the light oil gas.

The regenerated high-temperature contact agent can first exchange heat with a heat-taking medium, for example, water, low temperature water vapor, etc., so that the regenerated contact agent is reduced to a suitable temperature, and then returned to the cracking section for recycling. Additionally, the regenerated contact agent can also provide part of the heat and catalytic activity required for cracking of the heavy oil in the cracking section.

The high-temperature light oil gas and the syngas ascend and discharge from the cracking section, and then are subjected to a gas-solid separation, so as to remove the carried carbon-deposited contact agent. The separated carbon-deposited contact agent can be returned into the cracking section and be recycled as a bed material for cracking of the heavy oil. At the same time, the obtained purified oil gas can be used to obtain a gas product such as a syngas, a dry gas and a liquefied gas, and a light oil product as well as possibly a heavy oil product by means of oil and gas fractionation, etc. Among them, the light oil product can be further cut to obtain liquid products with different distillation ranges, the heavy oil product can be returned to the cracking section for recycling and refining and processing; and the syngas can be used as a source of hydrogen in refineries.

Thus it can be seen that the present disclosure integrates the cracking section and the gasification section in the same coupled reactor, achieving mutual supply of materials and mutual complementation of heat in two reaction processes, i.e., the heavy oil cracking and the coke gasification. Compared with current process of heavy oil catalytic cracking and coke gasification, in which materials are transported and circulated among multiple reactors, the integrated method provided by the present disclosure can not only significantly reduce energy consumption during heavy oil processing and increase the yield of the light oil gas, but also solve the problem of high difficulty in material circulation operation at present, as well as solves the problem of large occupied area and high investment of the existing heavy oil processing devices.

The present disclosure does not specifically limit the aforementioned heavy oil material, for example, the heavy oil material can be one of viscous oil, super viscous oil, oil sand asphalt, atmospheric pressure heavy oil, vacuum residue, catalytic cracking slurry and solvent deoiled asphalt, etc., or a mixture of more thereof; and the heavy oil material can also be one of heavy tar and residue oil produced in the process of coal pyrolysis or liquefaction, heavy oil produced in the process of oil shale retorting, and derived heavy oil such as liquid product of low-temperature pyrolysis in biomass, or a mixture of more thereof.

The Inventors have found through research that the integrated method provided by the present disclosure has a good treatment effect on a heavy oil material with Conradson' carbon residue value of above 10 wt %, and still has very good treatment effect even on the heavy oil material with Conradson' carbon residue value of above 15 wt %, capable of obtaining a large number of light oil gases.

The contact agent used in the present disclosure can be a commonly used contact agent for decarbonization and upgrading at present, for example, it can be a silicon-aluminum material such as quartz sand, kaolin, clay, alumina, silica sol, montmorillonite, and illite, and it can also be an industrial balance agent or spent catalyst in fluid catalytic cracking (FCC), or one or more of red mud, steel slag, blast furnace ash, coal ash and other solid particles.

The inventors have found through research that it is preferable to select a contact agent with relatively low cracking activity. For example, a contact agent with the micro-activity index of 5-30 is selected to ensure relatively high cracking efficiency and yield of light oil in the process of cracking of the heavy oil. In a specific implementation of the present disclosure, the micro-activity index of the contact agent used is 10-20, for example, kaolin, clay, alumina, silica sol, and industrial balance agent or spent catalyst in the process of catalytic cracking, etc.

Further, the contact agent is preferably in the shape of microsphere, its particle size distribution is preferably in the range of 10-500 μm, so as to have good fluidization performance; in a specific implementation of the present disclosure, the particle size distribution of the used contact agent is in the range of 20-200 μm.

In the present disclosure, in the process of cracking of the heavy oil, a relatively high content of coke is preferably formed on the surface of the carbon-deposited contact agent, that is, the carbon-deposited contact agent having a relatively high content of coke enters into the gasification section to implement the gasification reaction, which is capable of preventing heating and cooling of a large number of contact agents in the process of the cracking reaction and the gasification reaction and ensure that the energy consumed in the process of heating is mainly used for the gasification reaction of the coke, thereby improving overall energy efficiency of the entire process of heavy oil processing.

Specifically, in the process of cracking, it is preferable to maintain the mass content of the coke on the surface of the contact agent above 20%. For example, a small weight ratio of the contact agent to the heavy oil (i.e. agent-oil ratio) can be used to ensure that a high content of coke is formed on the surface of the contact agent during the cracking process of the heavy oil.

In a specific implementation of the present disclosure, within the cracking section, a reaction temperature is usually controlled to be 450-700° C., a reaction pressure is controlled to be 0.1-3.0 Mpa, a reaction time is controlled to be 1-20 s, a superficial gas velocity is controlled to be 1-20 m/s, a weight ratio of the contact agent to the heavy oil material (agent-oil ratio) is controlled to be 0.1-1.0:1. Preferably, the reaction temperature of the cracking reaction is 480-580° C., the reaction pressure is 0.1-1.0 Mpa, for example, normal pressure, the reaction time is 3-15 s, the superficial gas velocity is 1-20 m/s, and the agent-oil ratio is 0.2-1.0:1, preferably 0.2-0.5:1.

At present, the agent-oil ratio during catalytic cracking of the heavy oil is usually greater than 1, the content of the coke on the surface of the catalyst (contact agent) is usually less than 5%, and thus, in the process of gasification regeneration, a large amount of heat needs to be consumed to heat the catalyst and provide heat for the cracking reaction, resulting in relatively low efficiency and relatively high energy consumption in the process of heavy oil lightening. Compared with the prior art, due to a relatively low agent-oil ratio in the process of cracking reaction, which can even be controlled below 0.5, such as 0.2-0.5, the use of the integrated method provided by the present disclosure does not require a large number of heat to achieve the regeneration of the contact agent, and the syngas produced in the process of the regeneration of the contact agent also provides heat for the cracking reaction, thus the entire heavy oil lightening process has very low energy consumption, significantly reducing the production cost of heavy oil processing.

The present disclosure does not specifically limit the gasification agent entering into the gasification section, and for example, the gasification agent can be water vapor, and it can also be oxygen-containing gas or a mixed gas of water vapor and oxygen-containing gas. The oxygen-containing gas can be, for example, air, oxygen, etc.

In a specific implementation of the present disclosure, within the gasification section, a reaction temperature is generally controlled to be 850-1200° C., a reaction pressure is generally controlled to be 0.1-6.0 Mpa, and a superficial gas velocity is generally controlled to be 0.1-5 m/s, residence time of the carbon-deposited contact agent can be controlled to be 1-20 min. The gasification reaction under the above conditions can ensure that the coke on the surface of the contact agent react is fully reacted to achieve the regeneration of the contact agent, and a syngas with high quality is obtained.

The syngas ascends into the cracking section from the gasification section, which not only can ensure the fluidization of the contact agent, but also provide heat required for the cracking reaction; additionally, the highly active hydrogen-rich syngas can further provide a hydrogen atmosphere for the cracking of the heavy oil, so as to inhibit the coke formation in the heavy oil cracking process and increase yield of the light oil gas. In practical production, excess syngas can also enrich the source of hydrogen in refineries.

In the present disclosure, before the carbon-deposited contact agent enters into the gasification section to implement the gasification reaction for regeneration, it is preferable to first perform a water vapor stripping treatment, so as to thoroughly remove a small amount of light oil gas remaining in the carbon-deposited contact agent, thereby facilitating the smooth progress of the gasification reaction. Specifically, after the water vapor stripping treatment, the carbon-deposited contact agent in the cracking section is transported outside the coupled reactor into the gasification section for regeneration.

In a specific implementation of the present disclosure, when performing the above water vapor stripping treatment, a mass ratio of the water vapor to the heavy oil material is controlled to be 0.03-0.3:1, a temperature of the water vapor is 200-400° C., a superficial gas velocity of the water vapor is 0.5-5.0 m/s. The water vapor can be obtained from low temperature water vapor or by heat exchange between water and the regenerated contact agent.

In the present disclosure, the carbon-deposited contact agent and the regenerated contact agent can be transported in the following three ways:

1) The carbon-deposited contact agent in the cracking section descends, and after the water vapor stripping treatment, it descends outside the coupled reactor and enters into the gasification section; after the carbon-deposited contact agent in the gasification section completes the gasification of the coke to achieve the regeneration, the obtained regenerated contact agent is led out of the gasification section, and is returned into the cracking section after being cooled by heat exchange through an external heat exchanger.

2) The carbon-deposited contact agent in the cracking section is led out of the upper part of the cracking section after water vapor stripping, descends outside the coupled reactor into the middle part of the gasification section. After the carbon-deposited contact agent is subjected to gasification and regeneration in the gasification section, the obtained regenerated contact agent undergoes a heat exchange through an internal heat exchanger, and then ascends into the cracking section together with the syngas.

In this case, the entire coupled reactor is similar to an updraft fluidized bed, the gas velocity in the coupled reactor is large, and a heavy oil material inlet is located at the lower part of the cracking section.

3) The carbon-deposited contact agent in the cracking section descends from the cracking section, and after water vapor stripping, the carbon-deposited contact agent is led out of the cracking section, and enters into the middle of the gasification section from the outside of the coupled reactor, and after the carbon-deposited contact agent is subjected to gasification and regeneration in the gasification section, the obtained regenerated contact agent is returned into the cracking section after being cooled by heat exchange through an external heat exchanger.

Before the high-temperature light oil gas and the syngas are discharged from the top of the cracking section, the carbon-deposited contact agent carried therein is led out of the cracking section and enters into the gasification section for gasification and regeneration, the obtained regenerated contact agent is returned into the cracking section after heat exchange through an external heat exchanger.

In the present disclosure, the light oil gas and the syngas are led out of the cracking section, and then are subjected to a gas-solid separation, so that a few of the carbon-deposited contact agent carried therein is separated, and the purified oil gas is obtained. The present disclosure does not particularly limit the specific gas-solid separation method, gas-solid separation methods commonly used in the field of petroleum processing can be used, such as cyclone separation.

Preferably, before the light oil gas and the syngas are subjected to the gas-solid separation, a washing and cooling treatment can be first performed on them, for example, they are subjected to heat exchange washing with a low temperature liquid oil such as a heavy oil material, so as to remove a small amount of fine powder of the contact agent carried in the high-temperature oil gas, and at the same time, the cooling and washing treatment can be used as a desuperheating section of the high-temperature oil gas, so as to inhibit reactions such as excessive cracking and coke formation. And since the amount of the heavy oil material after heat absorption is small, and the heavy oil material is dispersed after exchanging heat with the high-temperature light oil gas and the syngas, the heavy oil material can be used directly as a raw material for the cracking reaction.

As discussed above, the regenerated contact agent obtained by the gasification and regeneration in the gasification section can exchange heat through the heat exchanger arranged outside the coupled reactor, so that the temperature is reduced to a suitable temperature, and then the regenerated contact agent enters into the cracking section; or, the regenerated contact agent can also enter into the cracking section after being cooled by heat exchange through the heat exchanger arranged inside the coupled reactor. Compared with the internal heat exchanger, the use of the external heat exchanger is more conducive to flexible control of parameters such as the temperature of the regenerated contact agent after heat exchange, the rate at which the regenerated contact agent returns to the cracking section, and can increase the flexibility and reliability of operation to a certain extent.

The present disclosure further provides an integrated device for heavy oil contact lightening and coke gasification, for implementing the above integrated method, where the integrated device at least includes a coupled reactor, a heat exchanger and a gas-solid separator, where:

the coupled reactor includes a cracking section at an upper part and a gasification section at a lower part, and the cracking section and the gasification section communicate with each other;

the cracking section has a heavy oil material inlet, a carbon-deposited contact agent return port, a carbon-deposited contact agent outlet and an oil gas outlet; the gasification section has a gasification agent inlet and a carbon-deposited contact agent inlet; the carbon-deposited contact agent outlet of the cracking section is connected with the carbon-deposited contact agent inlet of the gasification section through an external transportation pipeline;

the heat exchanger is arranged inside the coupled reactor, or the heat exchanger is arranged outside the coupled reactor and is connected with the cracking section and the gasification section;

the gas-solid separator has an inlet, a solid discharge outlet and a gas discharge outlet, where the inlet of the gas-solid separator is connected with the oil gas outlet of the cracking section, and the solid discharge outlet of the gas-solid separator is connected with the carbon-deposited contact agent return port of the cracking section.

Further, a water vapor stripping section is provided at the upper part within the cracking section; and/or a water vapor stripping section is provided between the cracking section and the gasification section. For example, the water vapor stripping section is provided at the upper part within the cracking section, then the carbon-deposited contact agent carried upwards by the light oil gas and the syngas is first subjected to water vapor stripping in the water vapor stripping section, so as to separate the carbon-deposited contact agent from the high-temperature oil gas; for another example, the water vapor stripping section is provided between the cracking section and the gasification section, the carbon-deposited contact agent descends to pass through the water vapor stripping section for water vapor stripping, and then enters into the gasification section.

The integrated method for heavy oil contact lightening and coke gasification provided by the present disclosure achieve mutual supply of materials and mutual complementation of heat in two reactions, i.e., the heavy oil cracking and the coke gasification, by the coupled reactor integrated with the cracking section and the gasification section. Especially, by adjustment of conditions such as flow of the syngas, type of gasification agent, it is possible to further achieve the matching of material stream and energy stream during heavy oil processing, ensure the stability throughout the heavy oil processing, and improve overall energy efficiency; by selection of an appropriate contact agent and adjustment of reaction conditions such as the agent-oil ratio in the cracking reaction, it is also possible to achieve the maximization of the yields of oil products in the process of cracking of the heavy oil and the high efficiency of the gasification process, and achieve the oil-gas co-production of heavy oil resources.

Therefore, compared with current process of heavy oil catalytic cracking and coke gasification, in which materials are transported and circulated among multiple reactors, the integrated method provided by the present disclosure can not only significantly reduce energy consumption during heavy oil processing, increase the yield of the light oil gas and reduce difficulties in material circulation operations, but also reduce the occupied area of heavy oil processing devices, and reduce equipment investment costs.

The integrated device for heavy oil contact lightening and coke gasification is used for implementing the above integrated method. The utilization of the integrated device achieves mutual supply of materials and mutual complementation of heat in the two reactions, the heavy oil cracking and the coke gasification, reduces energy consumption and difficulties in material circulation operations in the process of heavy oil processing, and increases the yield of the light oil gas. In addition, the integrated device also has a small occupied area and a low investment cost.

