Method and system for oil-coal co-refining

文档序号：1444222 发布日期：2020-02-18 浏览：22次中文

阅读说明：本技术 一种油煤共炼的方法及其系统 (Method and system for oil-coal co-refining ) 是由吴治国王卫平王蕴王鹏飞邹亮于 2018-08-06 设计创作，主要内容包括：一种油煤共炼的方法及其系统,煤粉、石油基重质油、供氢溶剂油和催化剂按照一定比例混合配制成油煤浆,所述油煤浆经油煤共炼后得到低碳烃、汽油馏分、轻馏分物流、重馏分物流和渣油馏分,所得轻馏分物流进入第一加氢反应区进行反应,所得重馏分物流进入第二加氢反应区进行反应,二者所得液相物流分离所得的中间馏分可作为供氢溶剂油。本发明提供的油煤共炼方法及其系统,具有结焦少、油煤浆性能稳定、转化率高、操作周期长的特点。(Coal powder, petroleum-based heavy oil, hydrogen-supplying solvent oil and a catalyst are mixed according to a certain proportion to prepare coal oil slurry, the coal oil slurry is subjected to coal oil co-refining to obtain low-carbon hydrocarbons, gasoline fractions, light fraction material flows, heavy fraction material flows and residual oil fractions, the obtained light fraction material flows enter a first hydrogenation reaction zone for reaction, the obtained heavy fraction material flows enter a second hydrogenation reaction zone for reaction, and the middle fraction obtained by separating the two obtained liquid phase material flows can be used as the hydrogen-supplying solvent oil. The oil-coal co-refining method and the oil-coal co-refining system provided by the invention have the characteristics of less coking, stable oil-coal slurry performance, high conversion rate and long operation period.)

1. A method for oil-coal co-refining comprises the following steps:

(1) coal powder, petroleum-based heavy oil, hydrogen-supplying solvent oil and a catalyst are mixed according to a certain proportion to prepare coal oil slurry, the coal oil slurry reacts under the condition of coal oil co-refining reaction in the presence of hydrogen, the reaction effluent is separated and fractionated to obtain hydrogen-rich gas, low-carbon hydrocarbon, gasoline fraction, light fraction material flow, heavy fraction material flow and residual oil fraction,

(2) the light fraction material flow obtained in the step (1) enters a first hydrogenation reaction zone to contact with a hydrogenation catalyst I for reaction, the reaction effluent is separated to obtain a gas phase material flow I and a liquid phase material flow I,

(3) the heavy fraction material flow obtained in the step (1) enters a second hydrogenation reaction zone to contact with a hydrogenation catalyst II for reaction, the reaction effluent is separated to obtain a gas phase material flow II and a liquid phase material flow II,

(4) and (3) fractionating the liquid phase material flow I obtained in the step (2) and the liquid phase material flow II obtained in the step (3) independently or together to obtain low-carbon hydrocarbon, gasoline fraction and middle fraction, and returning part of the middle fraction obtained as hydrogen-supplying solvent oil to the step (1) for preparing the coal oil slurry.

2. The method according to claim 1, wherein the petroleum-based heavy oil is selected from one or more of atmospheric residue, vacuum residue, solvent deasphalted oil, deasphalted pitch, and catalytic cracking slurry oil.

3. The method of claim 1, wherein the coal fines are selected from the group consisting of ground fines from one or more of lignite, subbituminous coal, and bituminous coal, and wherein the coal fines have an average particle size of less than 0.15 mm.

4. The method according to claim 1, wherein the mass ratio of the pulverized coal to the petroleum-based heavy oil is 1:0.05 to 1: 0.99; the mass percentage of the hydrogen-donating solvent oil is 30-60% on the basis of the total mass of the coal oil slurry.

5. The method according to claim 1, wherein the catalyst in step (1) is an oil-coal co-production catalyst, preferably, the catalyst is a coal powder-supported nanoscale Fe-based catalyst, the active components are ferric oxide and hydrated ferric oxide, and the carrier is coal powder.

6. The method of claim 1, wherein the oil-coal co-refining reaction conditions are as follows: the reaction temperature is 400-500 ℃, the reaction pressure is 15-21 MPa, and the volume ratio of hydrogen to oil is 500-2000 Nm³/m³The retention time is 0.5-2 h.

7. The process of claim 1, wherein the cut point between the light fraction stream and the heavy fraction stream is 340 to 400 ℃, the initial boiling point of the light fraction stream is 205 ℃, and the final boiling point of the heavy fraction stream is 550 ℃.

8. The method according to claim 1, characterized in that the liquid phase stream I obtained in step (2) is subjected to fractional distillation to obtain gas, hydrocarbon fraction below 205 ℃ and hydrocarbon fraction above 205 ℃, the hydrocarbon fraction above 205 ℃ is directly mixed with the liquid phase stream II obtained in step (3), and the mixed stream is returned to the step (1) for preparing the coal oil slurry as hydrogen supply solvent oil.

9. The method of claim 1, wherein the first adding in step (2)The reaction conditions in the hydrogen reaction zone are: the hydrogen partial pressure is 10MPa to 20MPa, the reaction temperature is 300 ℃ to 400 ℃, and the volume ratio of hydrogen to oil is 300Nm to 1500Nm³/m³The volume airspeed is 0.3-1.5 h^-1。

10. The process according to claim 1, wherein the hydrogenation catalyst I in the step (2) comprises a carrier selected from at least one of alumina, alumina-silica and titania, and an active metal element supported on the carrier selected from at least one of nickel, cobalt, molybdenum and tungsten.

11. The process of claim 1, wherein the reaction conditions in the second hydrogenation reaction zone in step (3) are: the hydrogen partial pressure is 7MPa to 18MPa, the reaction temperature is 270 ℃ to 340 ℃, and the volume ratio of hydrogen to oil is 400 Nm to 1300Nm³/m³The volume airspeed is 0.2-1.0 h^-1。

12. The process according to claim 1, wherein the hydrogenation catalyst II in the step (3) comprises a carrier selected from alumina and/or alumina-silica and an active metal element supported on the carrier, and the active metal element is at least one selected from nickel, cobalt, molybdenum and tungsten.

13. The process according to claim 1, wherein the distillation range of the middle distillate is 205 to 550 ℃.

14. The method according to claim 1 or 8, wherein the hydrogen donating miscella has a composition of: 10-16 mass% of monocyclic aromatic hydrocarbon, 25-35 mass% of bicyclic aromatic hydrocarbon, 15-23 mass% of tricyclic aromatic hydrocarbon, 10-19 mass% of tetracyclic aromatic hydrocarbon, and 1-5 mass% of pentacyclic aromatic hydrocarbon.

15. A system for oil-coal co-refining comprises an oil-coal slurry preparation unit, an oil-coal slurry co-refining unit, a light fraction material flow hydrogenation unit, a heavy fraction material flow hydrogenation unit and a fractionation unit,

in the coal oil slurry preparation unit, coal powder, petroleum-based heavy oil, hydrogen supply solvent oil and a catalyst are mixed according to a certain proportion to prepare coal oil slurry,

in the coal oil slurry co-refining unit, the coal oil slurry reacts under the reaction condition of coal oil co-refining in the presence of hydrogen, the reaction effluent is separated and fractionated to obtain hydrogen-rich gas, low-carbon hydrocarbon, gasoline fraction, light fraction material flow, heavy fraction material flow and residual oil fraction,

in the light fraction material flow hydrogenation unit, the light fraction material flow contacts with a hydrogenation catalyst I in a first hydrogenation reaction area for reaction, the reaction effluent is separated to obtain a gas phase material flow I and a liquid phase material flow I,

in the heavy fraction material flow hydrogenation unit, the heavy fraction material flow contacts with a hydrogenation catalyst II in a second hydrogenation reaction area for reaction, the reaction effluent is separated to obtain a gas phase material flow II and a liquid phase material flow II,

in the fractionating unit, the liquid phase material flow I and the liquid phase material flow II are fractionated separately or together to obtain low carbon hydrocarbon, gasoline fraction and middle fraction,

the fractionating unit is communicated with the coal oil slurry preparation unit through a pipeline, and part of middle distillate obtained by the fractionating unit is used as hydrogen supply solvent oil and returns to the coal oil slurry preparation unit through the pipeline.

16. A system for oil-coal co-refining comprises an oil-coal slurry preparation unit, an oil-coal slurry co-refining unit, a light fraction material flow hydrogenation unit, a heavy fraction material flow hydrogenation unit and a fractionation unit,

in the coal oil slurry preparation unit, coal powder, petroleum-based heavy oil, hydrogen supply solvent oil and a catalyst are mixed according to a certain proportion to prepare coal oil slurry,

fractionating the liquid phase material flow I in a fractionating unit to obtain gas, hydrocarbon fractions below 205 ℃ and hydrocarbon fractions above 205 ℃, mixing the hydrocarbon fractions above 205 ℃ with the liquid phase material flow II obtained in the step (3) to obtain a mixed material flow,

the fractionating unit is communicated with the coal oil slurry preparation unit through a pipeline, and the mixture flow obtained by the fractionating unit is used as hydrogen supply solvent oil and returns to the coal oil slurry preparation unit through the pipeline.

Technical Field

The invention relates to a method and a system for oil-coal co-refining.

Background

Among the technologies for coal conversion, the energy efficiency of high-pressure hydropyrolysis, i.e., hydro-liquefaction or direct liquefaction, is as high as 59%, which is more than 10% higher than that of indirect liquefaction. The oil-coal co-refining technology is originated from the coal direct liquefaction technology and also has the advantage of high energy efficiency.

In the initial oil-coal co-refining prior art, petroleum distillate oil is used for replacing directly liquefied solvent oil, thereby simplifying the process flow and reducing the investment of devices and the operation cost. However, petroleum distillates are of a wide variety and many are not suitable for direct replacement of hydrogen donor solvent oils.

CN104178214A "a method for preparing liquid fuel by co-refining visbreaking heavy oil and coal" discloses: (1) heating the heavy oil at 400-500 ℃ for no more than 30min, and performing thermal cracking viscosity reduction treatment to obtain a viscosity reduction product; (2) separating the viscosity-reducing product in the step (1) to obtain a gas-phase substance and a liquid-phase substance; (3) adding solvent oil into the liquid phase substance obtained in the step (2) and mixing uniformly to obtain a mixed solvent; (4) mixing the mixed solvent, the coal powder and the catalyst in the step (3) to prepare coal oil slurry; (5) carrying out hydrogenation reaction on the coal oil slurry to obtain liquid fuel; wherein the fraction of the liquid fuel at 250-500 ℃ is recycled to the step (3) to be used as the solvent oil. The invention adopts visbreaking heavy oil to replace heavy oil and coal powder to carry out co-refining reaction, and can greatly reduce the viscosity of coal slurry. The invention adopts viscosity-reducing heavy oil and circulating solvent oil to mix and then prepare the coal-oil slurry together with coal powder, and has the problem of poor hydrogen supply capability of the solvent oil.

CN106433775A discloses a kerosene refining method and a device thereof, the main contents of which are: mixing heavy oil, a non-hydrogenated circulating solvent and a first catalyst to prepare oil slurry, carrying out a first hydrocracking reaction on the oil slurry to obtain a first product, and separating the first product to obtain first light distillate oil and first heavy distillate oil; co-refining of kerosene: mixing the first heavy distillate oil, the coal powder and a second catalyst to prepare coal oil slurry, carrying out a second hydrocracking reaction on the coal oil slurry to obtain a second product, and separating the second product to obtain a second light distillate oil, a second heavy distillate oil and residues; solvent oil circulation: the second heavy distillate oil is used as an unhydrogenated circulating solvent for preparing the slurry oil; separating a finished product: and carrying out third hydrogenation upgrading on the first light distillate oil and the second light distillate oil to obtain a third product, and separating the third product to obtain the liquid fuel.

CN102041018A discloses a processing method for co-refining coal and oil, which mainly comprises the following steps: the coal and oil co-refining raw material is mixed with a hydrogen supply solvent, the hydrogen supply solvent comprises tetrahydronaphthalene or decahydronaphthalene, the mixing weight ratio of the coal and oil co-refining raw material to the hydrogen supply solvent is 1: 0.5-1: 10, and the mixing ratio of the coal and oil co-refining raw material is 2-50% of the mass of the coal. Treating the mixture of the coal and oil co-refining raw materials and the hydrogen donor solvent for 0.2-5 hours at the pressure of 15-40 MPa and the temperature of 300-500 ℃, and performing fractional distillation treatment after separating solid impurities from the treated product. The oil refers to one or more mixed oil of residual oil, oil sand, asphalt and synthetic oil.

In the prior art, the problems of serious coking and short operation period are easy to occur in the oil-coal co-refining process.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an oil-coal co-refining method and a system thereof so as to solve the technical problems of serious coking and short operation period in the oil-coal co-refining process.

The method provided by the invention comprises the following steps:

In the invention, the petroleum-based heavy oil is selected from one or more of atmospheric residue, vacuum residue, solvent deasphalted oil, deoiled asphalt and catalytic cracking slurry oil.

In the invention, the coal powder is selected from powder ground by one or more of lignite, subbituminous coal or bituminous coal, and the average particle size of the coal powder is less than 0.15 mm.

In the invention, the mass ratio of the pulverized coal to the petroleum-based heavy oil is preferably 1: 0.05-1: 0.99, and the mass percentage of the hydrogen-donating solvent oil is 30-60% based on the total mass of the coal oil slurry.

In the present invention, it is preferable that the oil coal co-refining reaction is performed in a slurry bed reactor.

In the invention, the catalyst is an oil-coal co-refining catalyst, which can be a commercially available oil-coal co-refining catalyst or a laboratory-prepared oil-coal co-refining catalyst. Preferably, the catalyst is an oil-coal co-making iron-based catalyst, further preferably, the catalyst is a coal powder-loaded nanoscale Fe-based catalyst, the active components are ferric oxide and hydrated ferric oxide, and the carrier is coal powder. The total mass of the coal oil slurry is taken as a reference, and the adding amount of the catalyst is 0.5-3.0% of the total mass of the coal powder and the petroleum-based heavy oil in terms of iron. Preferably, the auxiliary agent is added when the oil coal slurry is prepared. The auxiliary agent is a sulfur-containing compound, and is further preferably elemental sulfur, the addition amount of the auxiliary agent in the slurry oil is 1-2 mol% of sulfur to iron metal in the catalyst.

In the invention, the oil-coal co-refining reaction conditions are preferably as follows: the reaction temperature is 400-500 ℃, the reaction pressure is 15-21 MPa, and the volume ratio of hydrogen to oil is 500-2000 Nm³/m³The retention time is 0.5-2 h.

Further preferable oil-coal co-refining reaction conditions are as follows: the reaction temperature is 420-480 ℃, the reaction pressure is 15-19 MPa, and the volume ratio of hydrogen to oil is 600-1200 Nm³/m³。

In the invention, the obtained oil-coal co-refining reaction product is decompressed to be close to normal pressure through a pressure reducing valve bank, and then enters a separation tank for separation to obtain a gas phase material flow and a liquid phase material flow. And (4) separating low-carbon hydrocarbon and hydrogen-rich gas from the gas phase material flow through a low-pressure tower, and recycling the hydrogen-rich gas after pressurization. The liquid phase fraction enters a fractionating tower, and different fractions of materials, such as low carbon hydrocarbon, gasoline fraction, light fraction material flow, heavy fraction material flow and residual oil fraction, are separated. Preferably, the cutting point between the light fraction stream and the heavy fraction stream is 340-400 ℃, the initial boiling point of the light fraction stream is 205 ℃, and the final boiling point of the heavy fraction stream is 550 ℃.

According to the difference of the difficulty degree of hydrogenation reaction of the polycyclic aromatic hydrocarbon, two hydrogenation units are arranged to respectively carry out hydrogenation treatment on the light fraction material flow and the heavy fraction material flow. Aiming at different reaction purposes, more suitable hydrogenation reaction conditions are set to realize accurate operation and avoid excessive hydrogenation saturation, so that the hydrogen-supplying solvent oil with better property is obtained.

In step (2) of the present invention, the light fraction stream is contacted with a hydrogenation catalyst I in a first hydrogenation reaction zone to perform hydrodesulfurization, hydrodenitrogenation, and aromatic hydrogenation reactions. The inventor of the invention researches and discovers that the hydrogenation degree of the light fraction material flow obtained after cutting is relatively easier to control in the hydrotreating process, and monocyclic aromatic hydrocarbon in the product can be effectively reserved in the first hydrogenation reaction zone, so that the light fraction material flow is prevented from being over-saturated into naphthenic hydrocarbon. Preferably, the reaction conditions of the first hydrogenation reaction zone are as follows: the hydrogen partial pressure is 10MPa to 20MPa, the reaction temperature is 300 ℃ to 400 ℃, and the volume ratio of hydrogen to oil is 300Nm to 1500Nm³/m³The volume airspeed is 0.3-1.5 h^-1。

The hydrogenation catalyst I is a conventional hydrogenation refining catalyst, can be a commercially available hydrogenation refining catalyst, and can also be a hydrogenation refining catalyst prepared in a laboratory.

Preferably, the hydrogenation catalyst I comprises a carrier and an active metal element loaded on the carrier, wherein the carrier is selected from at least one of alumina, alumina-silica and titanium oxide, and the active metal element is selected from at least one of nickel, cobalt, molybdenum and tungsten; more preferably, in the hydrogenation catalyst I, the content of nickel and/or cobalt calculated by oxide is 1-30 wt%, and the content of molybdenum and/or tungsten calculated by oxide is 5-35 wt%, based on the total weight of the hydrogenation catalyst I.

In the step (3) of the invention, the obtained heavy fraction material flow is in contact with a hydrogenation catalyst II in a second hydrogenation reaction zone to carry out hydrodesulfurization, hydrodenitrogenation and aromatic hydrogenation saturation reactions. In the invention, the reaction depth of the second hydrogenation reaction zone is reasonably controlled, so that more bicyclic aromatic hydrocarbons, particularly more bicyclic aromatic hydrocarbons with hydrogen supply performance are obtained after the heavy fraction material flow is subjected to a hydrotreating process, and the hydrogen supply performance of the hydrogen supply solvent oil in a liquid phase is further optimized. Preferably, the reaction conditions of the second hydrogenation reaction zone are as follows: the hydrogen partial pressure is 7MPa to 18MPa, the reaction temperature is 270 ℃ to 340 ℃, and the volume ratio of hydrogen to oil is 400 Nm to 1300Nm³/m³The volume airspeed is 0.2-1.0 h^-1。

The hydrogenation catalyst II is a conventional hydrofining catalyst or a hydrotreating catalyst, can be a commercially available hydrofining catalyst or a hydrotreating catalyst, and can also be a hydrofining catalyst or a hydrotreating catalyst prepared in a laboratory.

Preferably, the hydrogenation catalyst II comprises a carrier and an active metal element loaded on the carrier, wherein the carrier is selected from alumina and/or alumina-silica, and the active metal element is selected from at least one of nickel, cobalt, molybdenum and tungsten; more preferably, in the hydrogenation catalyst II, the content of nickel and/or cobalt in terms of oxide is 1-30 wt%, and the content of molybdenum and/or tungsten in terms of oxide is 5-35 wt%, based on the total weight of the hydrogenation catalyst II.

In one embodiment of the present invention, hydrogenation catalyst I and hydrogenation catalyst II are the same.

In one embodiment of the invention, the liquid phase stream I obtained in the step (2) and the liquid phase stream II obtained in the step (3) are fractionated together to obtain low-carbon hydrocarbons, a gasoline fraction, a middle fraction and a residual oil, and part of the middle fraction is returned to the step (1) for preparing the coal oil slurry as the hydrogen-supplying solvent oil. The distillation range of the middle distillate is 205-550 ℃.

In one embodiment of the invention, the liquid phase material flow I obtained in the step (2) is subjected to fractional distillation to obtain gas, hydrocarbon fractions below 205 ℃ and hydrocarbon fractions above 205 ℃, the hydrocarbon fractions above 205 ℃ are directly mixed with the liquid phase material flow II obtained in the step (3), and the mixed material flow is used as hydrogen supply solvent oil to be returned to the step (1) for preparing the coal oil slurry.

Preferred compositions of the hydrogen donating mineral spirits are: 10-16 mass% of monocyclic aromatic hydrocarbon, 25-35 mass% of bicyclic aromatic hydrocarbon, 15-23 mass% of tricyclic aromatic hydrocarbon, 10-19 mass% of tetracyclic aromatic hydrocarbon, and 1-5 mass% of pentacyclic aromatic hydrocarbon. The optimized hydrogen-donating solvent oil can effectively reduce the hydrogen transfer resistance in the oil-coal co-refining process, and reasonably adjusts the oil-coal proportion, so that the conversion rate of a reaction system is improved, and the coking rate is reduced.

The invention also provides a system for oil-coal co-refining, which comprises an oil-coal slurry preparation unit, an oil-coal slurry co-refining unit, a light fraction material flow hydrogenation unit, a heavy fraction material flow hydrogenation unit and a fractionation unit,

in the coal oil slurry preparation unit, coal powder, petroleum-based heavy oil, hydrogen supply solvent oil and a catalyst are mixed according to a certain proportion to prepare coal oil slurry,

The invention also provides another system for oil-coal co-refining, which comprises an oil-coal slurry preparation unit, an oil-coal slurry co-refining unit, a light fraction material flow hydrogenation unit, a heavy fraction material flow hydrogenation unit and a fractionation unit,

in the coal oil slurry preparation unit, coal powder, petroleum-based heavy oil, hydrogen supply solvent oil and a catalyst are mixed according to a certain proportion to prepare coal oil slurry,

The invention has the advantages that:

(1) the oil-coal co-refining method and the oil-coal co-refining system provided by the invention have the characteristics of less coking, stable oil-coal slurry performance, high conversion rate and long operation period.

(2) The invention divides the appropriate light fraction material flow and heavy fraction material flow to respectively carry out the hydrotreatment by the appropriate cutting point, and simultaneously adopts the method of controlling the reaction depth of different hydrogenation reaction zones, thereby effectively improving the property of the final hydrogen-supplying solvent oil.

Detailed Description

The following examples further illustrate the invention but are not intended to limit the invention thereto.

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Method and system for oil-coal co-refining

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