Coal solvent oil processing technology

Abstract

The invention discloses a coal-to-solvent naphtha processing technology which comprises the following steps: step 1, synthesis gas preparation and purification: crushing, screening and drying raw material coal, and reacting the raw material coal with oxygen and water vapor in a high-temperature gasification device to generate crude synthesis gas; the crude synthesis gas is subjected to deep desulfurization and decarburization treatment after being subjected to dust removal and water washing cooling, and purified synthesis gas is obtained; step 2, Fischer-Tropsch synthesis and preliminary separation: carrying out Fischer-Tropsch synthesis reaction on the purified synthesis gas obtained in the step 1 in the presence of a catalyst to generate a product containing light hydrocarbons; carrying out cooling, gas-liquid separation and oil-water separation on the reaction product to obtain crude Fischer-Tropsch oil rich in C5-C11 light hydrocarbons; 3, light hydrocarbon fraction cutting and pretreatment, wherein crude Fischer-Tropsch oil is subjected to fractionation cutting to obtain a target fraction rich in C9-C11 alkane / olefin; through the implementation of the method, the Fischer-Tropsch synthesis catalyst and reaction conditions are optimized, the light hydrocarbon selectivity is remarkably improved, and the method has certain use value and popularization value.

Description

Technical Field

[0001] This invention relates to the field of coal-to-solvent oil processing technology, and more particularly to a coal-to-solvent oil processing method. Background Technology

[0002] Coal indirect liquefaction technology is an important direction for the clean utilization of coal. Solvent oils (such as D20 solvent oil) are high-value-added products widely used in industries such as coatings and inks. Traditional coal-to-solvent oil processes suffer from problems such as low yields of light hydrocarbons, poor product stability due to residual olefins and oxygen-containing compounds, and numerous cracking side reactions during fractionation. In existing technologies, the C5-C content in Fischer-Tropsch synthesis products... 11 The yield of light hydrocarbons is generally below 30%, and excessively high hydrorefining temperatures can easily trigger cracking. Furthermore, the color of the product (Ceport Special) is often below +25, making it difficult to meet the demands of the high-end market.

[0003] In conclusion, there is an urgent need to develop a highly efficient and selective coal-to-solvent oil processing technology. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a coal-to-solvent oil processing technology, aiming to solve the aforementioned problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a coal-to-solvent oil processing technology, comprising the following steps:

[0006] Step 1: Syngas preparation and purification. After crushing, screening and drying, the raw coal reacts with oxygen and water vapor in a high-temperature gasification unit to generate crude syngas.

[0007] The crude syngas is subjected to dust removal, water washing and cooling, and then undergoes deep desulfurization and decarbonization treatment to obtain purified syngas.

[0008] Step 2: Fischer-Tropsch synthesis and preliminary separation. The purified syngas obtained in Step 1 is subjected to Fischer-Tropsch synthesis in the presence of a catalyst to produce products containing light hydrocarbons.

[0009] The reaction products were cooled, subjected to gas-liquid separation and oil-water separation, to obtain a product rich in C5-C. 11 Crude Fischer-Tropsch oil of light hydrocarbons;

[0010] Step 3: Light hydrocarbon fractionation and pretreatment. Crude Fischer-Tropsch oil is fractionated to extract C9-C-rich fractions. 11 Target fraction of alkane / olefin;

[0011] The target fraction is subjected to deacidification and refining treatment;

[0012] Step 4: Deep hydrogenation refining, the target fraction obtained in step 3 is subjected to hydrogenation reaction in the presence of hydrogenation catalyst and hydrogen gas;

[0013] The hydrogenation reaction saturates olefins, converts and removes oxygen-containing compounds, and deeply removes sulfur and nitrogen impurities;

[0014] The hydrogenation product is separated to remove light components, yielding refined oil;

[0015] Step 5: Precision fractionation and product blending. The refined oil is fractionated under reduced pressure to separate and cut the target solvent oil fraction at 120-160℃.

[0016] An antioxidant is added to the target solvent oil fraction, and the boiling range is adjusted to meet the following conditions: initial boiling point ≥120℃ and final boiling point ≤160℃.

[0017] Step 6: Product Refining and Storage. The blended product undergoes adsorption refining to remove polar impurities, followed by precision filtration, and finally storage under inert gas protection.

[0018] Preferably, in step 1, the high-temperature gasification device is an entrained flow gasifier, and the raw coal is crushed and screened to a particle size of 0.5-10 mm, dried to a moisture content of <10%, and the gasification reaction conditions are: temperature 1300-1600℃, pressure 4.0-6.5 MPa, and oxygen purity >95%.

[0019] The deep desulfurization and decarbonization treatment adopts low-temperature methanol washing or MDEA amine method to make H2S+COS<0.1ppm and CO2<1%. The removed H2S is sent to the Claus unit to recover sulfur.

[0020] Preferably, the fluidized bed gasifier is a Shell furnace or a GSP furnace, and the gasification reaction comprises:

[0021] C + H₂O → CO + H₂ and C + O2→CO.

[0022] Preferably, the catalyst is a cobalt-based catalyst or an iron-based catalyst;

[0023] The Fischer-Tropsch synthesis reaction conditions are: pressure 2.0-3.0 MPa, H2 / CO molar ratio 2.0-2.2; the reactor is a fixed-bed reactor or a slurry-bed reactor; and the reactor is rich in C5-C. 11 Crude Fischer-Tropsch oil of light hydrocarbons accounts for 30-50% of the liquid phase products.

[0024] Preferably, the cobalt-based catalyst is Co / Al2O3 or Co / SiO2, and the iron-based catalyst is Fe-Cu-K / SiO2.

[0025] Preferably, in step 3, the fractionation is carried out under normal pressure to cut out a 120-160℃ fraction as the target fraction; the fractionation also cuts out: a light fraction <120℃ as naphtha feedstock, and a heavy fraction >160℃ sent to hydrocracking or used as fuel; and the deacidification and refining process includes sequential alkaline washing and water washing until neutral.

[0026] Preferably, in step 4, the hydrogenation catalyst is a Ni-Mo / Al2O3 or Pt-Pd molecular sieve catalyst, and the hydrogenation reaction conditions are: temperature 180-250℃, pressure 2.0-4.0MPa, and hydrogen-to-oil ratio 300-500 Nm³ / m³. The hydrogenation reaction objectives include: saturation conversion of olefins to alkanes, conversion of oxygen-containing compounds to hydrocarbons and water, and deep desulfurization / denitrification to a sulfur and nitrogen content of <1ppm.

[0027] Preferably, in step 5, the reduced pressure fractionation is carried out at a pressure of 10-30 kPa, the light component with a temperature <110℃ is cut off at the top of the fractionation column, the heavy component at the bottom of the column is recycled and hydrocracking, and the antioxidant is BHT.

[0028] Preferably, in step 6, the adsorption purification uses activated clay or molecular sieves, and the precision filtration uses a 1-5μm filter.

[0029] Preferably, in step 6, the inert gas is nitrogen, and the purified product has a Cerberus number ≥ +30.

[0030] The substantial effects of this invention:

[0031] 1. In this invention, by optimizing the Fischer-Tropsch synthesis catalyst and reaction conditions, the selectivity of light hydrocarbons is significantly improved, enabling C5-C hydrocarbons to be synthesized more readily. 11 The component yield is 30-50%.

[0032] 2. In this invention, low-temperature deep hydrogenation refining combined with precision vacuum fractionation is used to completely remove olefins, oxygen-containing compounds and sulfur and nitrogen impurities while avoiding cracking, resulting in excellent product stability.

[0033] 3. In this invention, through adsorption purification and nitrogen sealing storage, the color of the solvent oil reaches ≥+30 of the Cepor Special number, which far exceeds the industry requirements, meets the needs of high-end applications, and represents a significant advancement. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0035] To facilitate understanding of the present invention, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected to" another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this specification are for illustrative purposes only.

[0036] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0037] Example 1:

[0038] A coal-to-solvent oil processing technology includes the following steps:

[0039] Step 1: Syngas preparation and purification. After crushing, screening and drying, the raw coal reacts with oxygen and water vapor in a high-temperature gasification unit to generate crude syngas.

[0040] After dust removal, water washing and cooling, the crude syngas undergoes deep desulfurization and decarbonization treatment to obtain purified syngas.

[0041] Step 2: Fischer-Tropsch synthesis and preliminary separation. The purified syngas obtained in Step 1 is subjected to Fischer-Tropsch synthesis in the presence of a catalyst to produce products containing light hydrocarbons.

[0042] The reaction products were cooled, subjected to gas-liquid separation and oil-water separation, to obtain a product rich in C5-C. 11 Crude Fischer-Tropsch oil of light hydrocarbons;

[0043] Step 3: Light hydrocarbon fractionation and pretreatment. Crude Fischer-Tropsch oil is fractionated to extract C9-C-rich fractions. 11 Target fraction of alkane / olefin;

[0044] The target fraction undergoes deacidification and refining treatment;

[0045] Step 4: Deep hydrogenation refining, the target fraction obtained in step 3 is subjected to hydrogenation reaction in the presence of hydrogenation catalyst and hydrogen gas;

[0046] Hydrogenation saturates olefins, converts and removes oxygen-containing compounds, and deeply removes sulfur and nitrogen impurities;

[0047] The hydrogenation product is separated to remove light components, yielding refined oil;

[0048] Step 5: Precision fractionation and product blending. The refined oil is fractionated under reduced pressure to separate and cut the target solvent oil fraction at 120-160℃.

[0049] Add antioxidants to the target solvent oil fraction and adjust the boiling range to meet the following conditions: initial boiling point ≥120℃ and final boiling point ≤160℃;

[0050] Step 6: Product Refining and Storage. The blended product undergoes adsorption refining to remove polar impurities, followed by precision filtration, and finally storage under inert gas protection.

[0051] In one implementation method, in step 1, the high-temperature gasification device is an entrained flow gasifier, and the raw coal is crushed and screened to a particle size of 0.7 mm and dried to a moisture content of <10%. The gasification reaction conditions are: temperature 1450℃, pressure 5.5 MPa, and oxygen purity >95%.

[0052] The deep desulfurization and decarbonization treatment adopts a low-temperature methanol washing method to make H2S+COS<0.1ppm and CO2<1%. The removed H2S is sent to the Claus unit to recover sulfur.

[0053] In one implementation, the fluidized bed gasifier is a Shell furnace, and the gasification reaction includes:

[0054] C + H₂O → CO + H₂ and C + O2→CO.

[0055] In one implementation method, the catalyst is a cobalt-based catalyst;

[0056] The Fischer-Tropsch synthesis reaction conditions were: temperature 220℃, pressure 2.6 MPa, H2 / CO molar ratio 2.1; the reactor was a fixed-bed reactor and rich in C5-C. 11 Crude Fischer-Tropsch oil of light hydrocarbons accounts for 40% of the liquid phase products.

[0057] In one implementation, the cobalt-based catalyst is Co / Al2O3, and the iron-based catalyst is Fe-Cu-K / SiO2.

[0058] In one implementation, in step 3, the fractionation is carried out under atmospheric pressure, and a 140°C fraction is cut off as the target fraction; at the same time, the fractionation also cuts off: a light fraction of <120°C as naphtha feedstock, and a heavy fraction of >160°C sent to hydrocracking; and the deacidification and refining process includes sequential alkaline washing and water washing until neutral.

[0059] In one implementation method, in step 4, the hydrogenation catalyst is Ni-Mo / Al2O3, and the hydrogenation reaction conditions are: temperature 210℃, pressure 3.0MPa, hydrogen-to-oil ratio 400 Nm³ / m³. The hydrogenation reaction objectives include: saturation conversion of olefins to alkanes, conversion of oxygen-containing compounds to hydrocarbons and water, and deep desulfurization / denitrification to sulfur and nitrogen content <1ppm.

[0060] In one implementation, in step 5, the reduced pressure fractionation is carried out at a pressure of 20 kPa. The light component with a temperature <110°C is cut off from the top of the fractionation column, and the heavy component with a temperature >160°C is recycled for hydrocracking at the bottom of the column. The antioxidant is BHT.

[0061] In one implementation, in step 6, activated clay is used for adsorption purification, and a 3μm filter is used for precision filtration.

[0062] In one implementation method, in step 6, the inert gas is nitrogen, and the purified product has a specialty number ≥ +30.

[0063] Example 2:

[0064] This embodiment is basically the same as Embodiment 1, except that:

[0065] Step 1: Syngas preparation and purification; raw coal (bituminous coal) is crushed to a particle size of 5mm and dried to a moisture content of 8%;

[0066] In a Shell fluidized bed gasifier, oxygen and water vapor with a purity >95% are introduced and reacted at 1500℃ and 5.0MPa to generate crude syngas.

[0067] After the crude syngas is filtered by a ceramic filter for dust removal and cooled to 220°C by water washing, it is desulfurized and decarbonized by low-temperature methanol washing (H2S+COS<0.05ppm, CO2<0.8%). The H2S is sent to the Claus unit to recover sulfur.

[0068] Step 2: Fischer-Tropsch synthesis and separation. The purified synthesis gas is introduced into a slurry bed reactor and reacted at 220℃, 2.5MPa, and H2 / CO=2.1 using a Co / SiO2 catalyst.

[0069] The product was cooled to 40°C and then separated: the gas phase was recycled, and crude Fischer-Tropsch oil (C5-C5) was obtained through oil-water separation. 11 The component accounts for 45% of the liquid phase product.

[0070] Step 3: Fraction cutting and pretreatment, crude Fischer-Tropsch oil atmospheric distillation cutting:

[0071] <120℃ fraction: naphtha feedstock;

[0072] Target fraction at 120-160℃ (C9-C) 11(Olefin content 40%)

[0073] 160℃ heavy fraction: sent to hydrocracking;

[0074] The target fraction was washed with 5% NaOH solution and water until neutral.

[0075] Step 4: Deep hydrogenation refining, using Ni-Mo / Al2O3 catalyst, hydrogenation is carried out at 200℃, 3.0MPa, and a hydrogen-to-oil ratio of 400 Nm³ / m³.

[0076] The hydrogenation product is dehydrogenated in a stabilization tower to remove light hydrocarbons, and the refined oil has a sulfur content of <0.5ppm and a nitrogen content of <0.3ppm.

[0077] Step 5: Precision fractionation and blending. The refined oil is fractionated under reduced pressure at 20 kPa, and the 120-160℃ fraction is cut off by side stream (95% point = 158℃).

[0078] Add 0.01% BHT antioxidant and adjust the distillation range to an initial boiling point of 122℃ and a final boiling point of 159℃.

[0079] Step 6: Product refining and storage, impurities are removed by activated clay adsorption, and particles are removed by a 1μm filter;

[0080] Nitrogen-sealed storage, the product is water-white (Cepor Special +32).

[0081] Example 3:

[0082] This embodiment is basically the same as Embodiment 1, except that:

[0083] Step 1: Syngas preparation, lignite crushed to 8mm, dried to 9% moisture content;

[0084] GSP gasification furnace reaction: 1400℃, 4.5MPa, oxygen purity >96%.

[0085] Step 2: Fischer-Tropsch synthesis, fixed-bed reactor, Fe-Cu-K / SiO2 catalyst, 260℃, 2.8MPa, H2 / CO=2.0;

[0086] C5-C in crude Fischer-Tropsch oil 11 The component accounts for 38%.

[0087] Step 3: Fraction cutting, atmospheric distillation to obtain the target fraction at 120-160℃ (alkali washing + water washing).

[0088] Step 4: Hydrogenation refining, using Pt-Pd molecular sieve catalyst, 230℃, 3.5MPa, hydrogen-to-oil ratio of 450 Nm³ / m³;

[0089] The refined oil has a sulfur content of <0.8ppm and a nitrogen content of <0.6ppm.

[0090] Step 5: Fractional distillation and blending, fractional distillation under reduced pressure at 15 kPa, add BHT to the side stream fraction;

[0091] Distillation range: initial boiling point 121℃, final boiling point 160℃.

[0092] Step 6: Product processing, molecular sieve adsorption, 3μm filtration, nitrogen sealing storage;

[0093] Product color: Cerberus Special Number +30.

[0094] Comparative example:

[0095] The Fischer-Tropsch synthesis uses an iron-based catalyst (temperature not optimized), C5-C 11 The yield was only 25%;

[0096] Hydrogenation temperature of 280℃ results in a cracking rate >15%;

[0097] The product has a sulfur content of 5 ppm and a color grade of Seybert-5 (yellowish).

[0098] Table 1: Comparison of experimental results.

[0099]

[0100] This invention significantly improves product quality and yield through optimization of the entire process of gasification-Fischer-Tropsch-hydrogenation-fractionation, and is especially suitable for the production of high-end solvent oils.

[0101] It should be noted that while the preferred embodiments of the present invention are provided in the specification and accompanying drawings, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are not intended to impose additional limitations on the content of the present invention; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of the present invention. Furthermore, the above-described technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of the present invention specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A coal-to-solvent oil processing technology, characterized in that, Includes the following steps: Step 1: Syngas preparation and purification. After crushing, screening and drying, the raw coal reacts with oxygen and water vapor in a high-temperature gasification unit to generate crude syngas. The crude syngas is subjected to dust removal, water washing and cooling, and then undergoes deep desulfurization and decarbonization treatment to obtain purified syngas. Step 2: Fischer-Tropsch synthesis and preliminary separation. The purified syngas obtained in Step 1 is subjected to Fischer-Tropsch synthesis in the presence of a catalyst to produce products containing light hydrocarbons. The reaction products were cooled, subjected to gas-liquid separation and oil-water separation, to obtain a product rich in C5-C. 11 Crude Fischer-Tropsch oil of light hydrocarbons; Step 3: Light hydrocarbon fractionation and pretreatment. Crude Fischer-Tropsch oil is fractionated to extract C9-C-rich fractions. 11 Target fraction of alkane / olefin; The target fraction is subjected to deacidification and refining treatment; Step 4: Deep hydrogenation refining, the target fraction obtained in step 3 is subjected to hydrogenation reaction in the presence of hydrogenation catalyst and hydrogen gas; The hydrogenation reaction saturates olefins, converts and removes oxygen-containing compounds, and deeply removes sulfur and nitrogen impurities; The hydrogenation product is separated to remove light components, yielding refined oil; Step 5: Precision fractionation and product blending. The refined oil is fractionated under reduced pressure to separate and cut the target solvent oil fraction at 120-160℃. An antioxidant is added to the target solvent oil fraction, and the boiling range is adjusted to meet the following conditions: initial boiling point ≥120℃ and final boiling point ≤160℃. Step 6: Product Refining and Storage. The blended product undergoes adsorption refining to remove polar impurities, followed by precision filtration, and finally storage under inert gas protection.

2. The coal-to-solvent oil processing technology according to claim 1, characterized in that, In step 1, the high-temperature gasification device is an entrained flow gasifier, and the raw coal is crushed and screened to a particle size of 0.5-10 mm, dried to a moisture content of <10%, and the gasification reaction conditions are: temperature 1300-1600℃, pressure 4.0-6.5 MPa, and oxygen purity >95%. The deep desulfurization and decarbonization treatment adopts low-temperature methanol washing or MDEA amine method to make H2S+COS<0.1ppm and CO2<1%. The removed H2S is sent to the Claus unit to recover sulfur.

3. The coal-to-solvent oil processing technology according to claim 2, characterized in that, The fluidized bed gasifier is a Shell furnace or a GSP furnace, and the gasification reaction includes: C + H₂O → CO + H₂ and C + O2→CO.

4. The coal-to-solvent oil processing technology according to claim 1, characterized in that, In step 2, the catalyst is a cobalt-based catalyst or an iron-based catalyst; The Fischer-Tropsch synthesis reaction conditions are: pressure 2.0-3.0 MPa, H2 / CO molar ratio 2.0-2.2; the reactor is a fixed-bed reactor or a slurry-bed reactor; and the reactor is rich in C5-C. 11 Crude Fischer-Tropsch oil of light hydrocarbons accounts for 30-50% of the liquid phase products.

5. The coal-to-solvent oil processing technology according to claim 4, characterized in that, The cobalt-based catalyst is Co / Al2O3 or Co / SiO2, and the iron-based catalyst is Fe-Cu-K / SiO2.

6. The coal-to-solvent oil processing technology according to claim 1, characterized in that, In step 3, the fractionation is carried out under normal pressure to cut out a 120-160℃ fraction as the target fraction; at the same time, the fractionation also cuts out: a light fraction <120℃ as naphtha feedstock, and a heavy fraction >160℃ sent to hydrocracking or used as fuel; and the deacidification and refining process includes sequential alkaline washing and water washing until neutral.

7. The coal-to-solvent oil processing technology according to claim 1, characterized in that, In step 4, the hydrogenation catalyst is a Ni-Mo / Al2O3 or Pt-Pd molecular sieve catalyst, and the hydrogenation reaction conditions are: temperature 180-250℃, pressure 2.0-4.0MPa, and hydrogen-to-oil ratio 300-500 Nm³ / m³. The hydrogenation reaction objectives include: saturation conversion of olefins to alkanes, conversion of oxygen-containing compounds to hydrocarbons and water, and deep desulfurization / denitrification to a sulfur and nitrogen content of <1ppm.

8. The coal-to-solvent oil processing technology according to claim 1, characterized in that, In step 5, the reduced pressure fractionation is carried out at a pressure of 10-30 kPa. The light component with a temperature <110℃ is cut off from the top of the fractionation column, and the heavy component at the bottom of the column is recycled for hydrocracking. The antioxidant is BHT.

9. The coal-to-solvent oil processing technology according to claim 1, characterized in that, In step 6, the adsorption purification uses activated clay or molecular sieves, and the precision filtration uses a 1-5μm filter.

10. The coal-to-solvent oil processing technology according to claim 9, characterized in that, In step 6, the inert gas is nitrogen, and the purified product has a special number of ≥+30.

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