Method and device for processing intermediate products of preparing long-chain alkanes from sugar platform compounds

Abstract

An embodiment of the present invention provides a method and device for processing an intermediate product of preparing long-chain alkanes from a sugar platform compound, the method comprising: mixing a condensation product of a sugar platform compound with an oxygen-containing solvent and then performing a hydrogenation pretreatment; performing gas-liquid separation on the reacted material to obtain a liquid mixture; and separating the oxygen-containing solvent from the liquid mixture. The method of an embodiment of the present invention can continuously convert the solid intermediate product of preparing long-chain alkanes from the sugar platform into a liquid intermediate product by hydrogenating the solid intermediate product in an oxygen-containing solvent and separating the oxygen-containing solvent from the hydrogenated product, which not only realizes the continuous hydrogenation of the solid intermediate product, but also avoids the participation of the solvent in the subsequent hydrogenation deoxygenation process.

Description

Technical Field

[0001] The invention relates to preparing long-chain alkanes from sugar platform compounds, in particular to a method and device for processing intermediate products of preparing long-chain alkanes from sugar platform compounds. Background Art

[0002] In the context of the oil crisis and the increasingly serious greenhouse effect, biomass, as the only renewable energy source containing carbon sources, is currently the most promising resource for preparing hydrocarbon liquid fuels to replace oil. In order to sustain the transition from fossil energy economy to carbohydrate economy and convert biomass into high-value-added fuels and chemicals, the Dumesic team used furfural, a product of lignocellulose hydrolysis, as raw material, and first extended the carbon chain through aldol condensation reaction to obtain furfural acetone [4-(2-furanyl)-3-butene-2-one] and diconylidene acetone [1,5-bis-(2-furanyl)-1,4-pentadien-3-one], and then hydrodeoxygenated them to obtain C8 straight-chain alkanes and C 13 Straight-chain alkanes are finally isomerized to obtain qualified jet fuel components, achieving efficient utilization of biomass (science, 2005, 308, 1446-1450).

[0003]

[0004] Since the condensed difurfuryl acetone is solid, it cannot be directly fed into a tubular reactor for continuous processing. Difurfuryl acetone is insoluble in various hydrocarbons and is only partially soluble in oxygen-containing solvents such as ethanol and acetone. Although difurfuryl acetone can be dissolved in oxygen-containing solvents and pumped into the reactor, the hydrogenation process will cause the hydrogenation and deoxygenation reaction of the oxygen-containing solvent, consuming the solvent and hydrogen to generate cheap low-carbon alkanes.

[0005] To overcome this defect, it is necessary to pre-treat the difurfuryl acetone by hydrogenation to saturate the C=C and C=O double bonds, thereby converting the difurfuryl acetone into a liquid that can be dissolved in saturated alkanes. This not only allows the raw material to enter the continuous tubular reactor in liquid form, but also reduces the exothermic effect in the subsequent hydrodeoxygenation process.

[0006] On the other hand, furfural acetone, difurfuryl acetone and the like have large conjugated structures with furan rings and C=C double bonds, are unstable at high temperatures, and are prone to side reactions such as self-polymerization. Therefore, they need to be pretreated with hydrogenation at a lower temperature to saturate the C=C and C=O double bonds to avoid side reactions during the hydrodeoxygenation process at a higher temperature.

[0007]

[0008] At present, there are few reports on the pre-hydrogenation treatment of difurfuryl acetone and other similar substances, and the only reports are also about hydrogenation pretreatment in an intermittent tank reactor. Chinese patent application CN104650947A discloses a pre-hydrogenation treatment method for similar raw materials: under the action of a catalyst, hydrogenation pretreatment is achieved in a tank reactor. However, the operation process of this method cannot be continuous, and the pre-hydrogenation product containing an oxygen-containing solvent such as ethanol obtained by this process is subjected to a hydrodeoxygenation reaction, which inevitably causes the hydrodeoxygenation of the solvent, produces light alkanes with lower production value, and causes solvent waste. Summary of the invention

[0009] A main purpose of the present invention is to provide a method for treating an intermediate product of preparing long-chain alkanes from a sugar platform compound, comprising:

[0010] The condensation product of the sugar platform compound is mixed with an oxygen-containing solvent and then subjected to hydrogenation pretreatment;

[0011] Separating the reacted materials into gas and liquid to obtain a liquid mixture; and

[0012] The oxygenated solvent is separated from the liquid mixture.

[0013] According to one embodiment of the present invention, the method comprises mixing the sugar platform compound condensation product with the oxygen-containing solvent and then preheating the mixture, and then performing the hydrogenation pretreatment after the preheating.

[0014] According to one embodiment of the present invention, the sugar platform compound condensation product is prepared by an aldol condensation reaction between a compound of formula (1) and a compound of formula (2) or formula (3);

[0015] Formula (1) Formula (2) Formula (3)

[0016] R1 is selected from -H, -CH2OH, -CH2OCH3, -CH2OCH2CH3, -CH2OC3H7 or -CH2OC4H9;

[0017] R2 is selected from -H, -CH3, -CH2CH3, -C3H7 or -C4H9;

[0018] R3 and R4 are independently selected from -CH3, -CH2CH3, -C3H7 or -C4H9.

[0019] According to one embodiment of the present invention, the oxygen-containing solvent is selected from one or more of methanol, ethanol, acetone and tetrahydrofuran.

[0020] An embodiment of the present invention provides a processing device for preparing an intermediate product of a long-chain alkane from a sugar platform compound, comprising:

[0021] mixer;

[0022] a hydrogenation reactor, connected to the mixer;

[0023] a first separator, connected to the hydrogenation reactor; and

[0024] The second separator is connected to the first separator.

[0025] According to one embodiment of the present invention, the device comprises a heating component connected to the mixer and the hydrogenation reactor respectively.

[0026] According to one embodiment of the present invention, the hydrogenation reactor is connected to the first separator through the bottom.

[0027] According to one embodiment of the present invention, the hydrogenation reactor is further connected to the top of the first separator via the top, so that a hydrogen circulation passage is formed between the hydrogenation reactor and the first separator.

[0028] According to one embodiment of the present invention, the second separator is communicated with the mixer, so that an oxygen-containing solvent circulation passage is formed between the second separator and the mixer.

[0029] According to one embodiment of the present invention, a condenser is provided on the oxygen-containing solvent circulation passage.

[0030] The method of one embodiment of the present invention can continuously convert the solid intermediate product of the sugar platform to long-chain alkanes into a liquid intermediate product by hydrogenating the solid intermediate product in an oxygen-containing solvent and separating the oxygen-containing solvent from the hydrogenated product. This not only realizes the continuous hydrogenation of the solid intermediate product, but also avoids the participation of the solvent in the subsequent hydrogenation deoxygenation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Various objects, features and advantages of the present invention will become more apparent by considering the following detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The accompanying drawings are merely exemplary illustrations of the present invention and are not necessarily drawn to scale. In the accompanying drawings, the same reference numerals always refer to the same or similar parts. Among them:

[0032] Figure 1 This is a schematic structural diagram of a processing device for preparing intermediate products of long-chain alkanes from sugar platform compounds according to one embodiment of the present invention. DETAILED DESCRIPTION

[0033] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially used for illustration purposes rather than for limiting the present invention.

[0034] The method for preparing long-chain alkanes using a sugar platform compound as a raw material comprises: a step of preparing an intermediate product, namely a sugar platform compound condensation product, by an aldol condensation reaction of the sugar platform compound, a step of pre-hydrogenating the sugar platform compound condensation product to obtain a saturated hydrogenated product, and a step of further subjecting the hydrogenated product to a hydrodeoxygenation process to obtain long-chain alkanes.

[0035] An embodiment of the present invention provides a method for treating an intermediate product of preparing long-chain alkanes from a sugar platform compound, comprising:

[0036] dispersing the sugar platform compound condensation product (solid) in an oxygen-containing solvent for hydrogenation reaction (hydrogenation pretreatment);

[0037] Separating the reacted materials into gas and liquid to obtain a liquid mixture; and

[0038] The oxygenated solvent is separated from the liquid mixture.

[0039] The method of one embodiment of the present invention can continuously convert the solid intermediate product of the sugar platform to long-chain alkanes into a liquid intermediate product by hydrogenating the solid intermediate product in an oxygen-containing solvent and separating the oxygen-containing solvent from the hydrogenated product. This not only realizes the continuous hydrogenation of the solid intermediate product, but also avoids the participation of the solvent in the subsequent hydrogenation deoxygenation process.

[0040] In one embodiment, the sugar platform compound can be one of the compounds of formula (1), formula (2) and formula (3). Wherein, R1 is selected from -H, -CH2OH, -CH2OCH3, -CH2OCH2CH3, -CH2OC3H7 or -CH2OC4H9; R2 is selected from -H, -CH3, -CH2CH3, -C3H7 or -C4H9; R3 and R4 are selected from -CH3, -CH2CH3, -C3H7 or -C4H9, respectively.

[0041] In one embodiment, the sugar platform compound condensation product is prepared by an aldol condensation reaction of a compound of formula (1) with a compound of formula (2) or formula (3);

[0042] Formula (1) Formula (2) Formula (3)

[0043] Wherein, R1 is selected from -H, -CH2OH, -CH2OCH3, -CH2OCH2CH3, -CH2OC3H7 or -CH2OC4H9; R2 is selected from -H, -CH3, -CH2CH3, -C3H7 or -C4H9; R3 and R4 are respectively selected from -CH3, -CH2CH3, -C3H7 or -C4H9.

[0044] In one embodiment, the sugar platform compound condensation product is one or more of the above-mentioned aldol condensation reaction products (reaction products of the compound of formula (1) with the compound of formula (2) or formula (3)).

[0045] In one embodiment, the condensation product of the sugar platform compound is difurfurylideneacetone and / or dihydroxymethylfurfuryl acetone

[0046] In one embodiment, the oxygen-containing solvent may be a low-boiling-point oxygen-containing solvent capable of dissolving the condensation product of the sugar platform compound, such as methanol, ethanol, acetone, tetrahydrofuran, and the like.

[0047] In one embodiment, a solid sugar platform compound condensation product is mixed with an oxygen-containing solvent to dissolve the solid product in the oxygen-containing solvent. In the resulting mixed solution, the mass fraction of the solid product can be 3 to 80%, and can further be 10 to 30%, for example, 15%, 20%, 25%, etc.

[0048] In one embodiment, the mixing of the sugar platform compound condensation product and the oxygen-containing solvent can be carried out under normal pressure and in an inert gas atmosphere, and the inert gas can be, for example, nitrogen.

[0049] In one embodiment, the mixture of the sugar platform compound condensation product and the oxygen-containing solvent is preheated, and the temperature of the preheated mixture is 60-200°C, such as 80°C, 100°C, 120°C, 150°C, 180°C, etc.

[0050] In one embodiment, under the action of a catalyst, a mixture of a condensation product of a sugar platform compound and an oxygen-containing solvent is reacted with hydrogen for hydrogenation. The partial pressure of hydrogen can be 1.0 to 10.0 MPa, the reaction temperature can be 60 to 200°C, and the volume space velocity can be 0.1 to 3.0 h -1 , the hydrogen-oil volume ratio can be 75-4000. Preferably, the hydrogen partial pressure is 2.5-6.0 MPa, the reaction temperature is 80-160°C, and the volume space velocity is 0.2-1.0 h -1 , hydrogen-oil volume ratio: 500~1500.

[0051] For example, the hydrogen partial pressure can be 3MPa, 4MPa, 4.5MPa, 5MPa, etc.; the reaction temperature can be 80°C, 100°C, 130°C, 150°C, etc.; the volume space velocity can be 0.2h -1 、0.5h -1 、0.8h -1 etc.; the volume ratio of hydrogen to oil can be 700, 1000, 1200, 1400, etc.

[0052] In one embodiment, the catalyst for the hydroprocessing includes but is not limited to a catalyst containing at least one Group VIB or Group VIII transition metal, preferably a catalyst containing at least one of the elements Ru, Pd, Pt, W, Mo, Co, Ni, etc. For example, the catalyst for the hydroprocessing may be NiO(SiO2)7, Ni-W / Al2O3.

[0053] In one embodiment, unreacted hydrogen is separated from the liquid product by gas-liquid separation, and the hydrogen can be recovered and recycled; at the same time, the oxygen-containing solvent separated from the liquid product can also be recovered and recycled.

[0054] The method of one embodiment of the present invention can be operated continuously and realize the recycling and reuse of the solvent, and the hydrogenation saturation of C=C and C=O double bonds in the raw material (intermediate product) is achieved under relatively mild conditions. After hydrogenation saturation, the raw material becomes liquid and can enter the subsequent high-temperature hydrodeoxygenation process, thereby improving the selectivity of the hydrodeoxygenation process.

[0055] The present invention further provides a device for realizing the method for processing the intermediate product of preparing long-chain alkanes from the sugar platform compound.

[0056] like Figure 1 As shown, a processing device for preparing intermediate products of long-chain alkanes from sugar platform compounds according to one embodiment of the present invention includes a mixer 1, a hydrogenation reactor 3, a first separator 4 and a second separator 5; wherein the mixer 1 is connected to the hydrogenation reactor 3, and the first separator 4 is connected to the hydrogenation reactor 3 and the second separator 5, respectively.

[0057] A stirrer is arranged in the mixer 1, and the sugar platform compound condensation product and the oxygen-containing solvent are mixed in the mixer 1 to form a mixed liquid.

[0058] In one embodiment, a heating component is provided between the mixer 1 and the hydrogenation reactor 3, and the heating component may be, for example, a heating furnace 2. The mixture is introduced into the heating furnace 2 for preheating to facilitate the subsequent hydrogenation process, and the mixed liquid may be pumped into the heating furnace 2 under a certain pressure, and the pressure may be, for example, 1.0 to 10.0 MPa.

[0059] In one embodiment, the heating furnace 2 and the hydrogen source are respectively connected to the top of the hydrogenation reactor 3 , that is, the mixed liquid and hydrogen enter from the top of the hydrogenation reactor 3 .

[0060] In one embodiment, the hydrogenation reactor 3 is connected to the first separator 4 through the bottom, so that the reacted materials enter the first separator 4 .

[0061] The first separator 4 is a gas-liquid separator, which is used to separate unreacted hydrogen from the liquid material. For example, the first separator 4 can be a high-pressure separator.

[0062] In one embodiment, the hydrogenation reactor 3 is also connected to the top of the first separator 4 through the top, so that a hydrogen circulation passage 10 is formed between the hydrogenation reactor 3 and the first separator 4, and the hydrogen separated from the first separator 4 can re-enter the hydrogenation reactor 3 through the hydrogen circulation passage 10 to participate in hydrogenation pretreatment.

[0063] In one embodiment, a circulating hydrogen compressor 11 is provided on the hydrogen circulation passage 10 .

[0064] In one embodiment, the hydrogen circulation passage 10 is communicated with the hydrogen source and the heating furnace 2 respectively.

[0065] In one embodiment, the first separator 4 is connected to the second separator 5 through the bottom, so that the liquid material obtained by gas-liquid separation enters the second separator 5 .

[0066] In one embodiment, the product is separated from the oxygen-containing solvent in the second separator 5 , and the second separator 5 may be a normal pressure separation tower.

[0067] In one embodiment, the second separator 5 is communicated with the mixer 1 , so that an oxygen-containing solvent circulation passage 20 is formed between the second separator 5 and the mixer 1 .

[0068] In one embodiment, the second separator 5 is connected to the mixer 1 through the top, and the separated oxygen-containing solvent enters the mixer 1 through the oxygen-containing solvent circulation passage 20 for recycling, and the product is discharged from the bottom of the second separator 5 and then subjected to subsequent hydrodeoxygenation treatment.

[0069] In one embodiment, a condenser 21 is provided on the oxygen-containing solvent circulation passage 20 .

[0070] In one embodiment, a raw material box (not shown) containing the oxygen-containing solvent is connected to the oxygen-containing solvent circulation passage 20 .

[0071] In the processing device for preparing the intermediate product of long-chain alkane from the sugar platform compound according to one embodiment of the present invention, during operation, the condensation product of the sugar platform compound enters the mixer 1, is mixed with the oxygen-containing solvent in the mixer 1, and is stirred and dissolved, and then enters the heating furnace 2 for preheating after being pressurized;

[0072] After preheating, the mixed liquid flows out of the heating furnace 2 and mixes with hydrogen in the hydrogen circulation passage 10, and then enters the hydrogenation reactor 3, and reacts under the action of the catalyst.

[0073] The materials after the reaction enter the first separator 4 and are separated into gas phase and liquid phase materials, wherein the gas phase materials enter the hydrogen circulation passage 10, and enter the hydrogenation reactor 3 for recycling after being pressurized by the circulating hydrogen compressor 11. The liquid phase materials enter the second separator 5 from the bottom of the first separator 4, and the top solvent separated in the second separator 5 enters the oxygen-containing solvent circulation passage 20, and enters the mixer 1 for recycling after being condensed by the condenser 21. The liquid phase material at the bottom of the second separator 5 is the liquid phase product after the C=C and C=O double bonds are saturated after the hydrogenation pretreatment, and is discharged from the bottom of the second separator 5 and enters the subsequent hydrodeoxygenation process.

[0074] The method / device of one embodiment of the present invention realizes the continuous hydrogenation pretreatment of the intermediate solid product of the production of long-chain alkanes from sugar platform compounds. Compared with the intermittent autoclave hydrogenation pretreatment method / device, it has the advantages of high efficiency and easy operation.

[0075] In the method of one embodiment of the present invention, the reaction conditions are mild, thereby avoiding the occurrence of side reactions of the intermediate solid raw materials at high temperatures.

[0076] Hereinafter, the method for processing the intermediate product of preparing long-chain alkanes from the sugar platform compound according to one embodiment of the present invention will be further described through specific examples.

[0077] In the embodiment, furfural or 5-hydroxymethylfurfural and two molecules of acetone are used to prepare product A difurfurylideneacetone by inorganic base catalytic condensation reaction. and B-dihydroxymethylfurfuryl acetone The NiO(SiO2)7 catalyst was prepared by coprecipitation method and used for hydrogenation pretreatment reaction after hydrogen reduction; the Ni-W / Al2O3 catalyst was prepared by equal volume impregnation method and used for hydrogenation pretreatment reaction after sulfidation.

[0078] Example 1

[0079] Difurfuryl acetone and ethanol are placed in a mixer 1, stirred and dissolved, and preheated in a heating furnace 2 before entering a hydrogenation reactor 3 together with hydrogen, where the reaction is carried out under the action of a hydrogenation pretreatment catalyst. The reacted materials are separated into gaseous and liquid phase streams by a first separator 4, wherein the gaseous phase stream hydrogen is recycled after being pressurized. The liquid phase stream enters a second separator 5, which is a normal pressure separation tower. The top stream is condensed by a condenser 21 and mixed with a new solvent before entering a mixer 1, and the bottom stream flows out of the device. The specific operating conditions and reaction results are shown in Table 1.

[0080] Example 2

[0081] Dihydroxymethylfurfuryl acetone The raw materials were the same as those in Example 1. The operating conditions and reaction results were shown in Table 1.

[0082] Example 3

[0083] The raw materials used in this example are the same as those in Example 1, the main difference being that acetone is used as the reaction solvent. The specific operating conditions and reaction results are shown in Table 1.

[0084] Table 1

[0085]

[0086]

[0087] Comparative Example

[0088] Choose Furfuryl Acetone As a solid raw material, it is filled into a mixer, heated and directly enters the reactor together with hydrogen, reacts under the action of a hydrogenation catalyst, and the product after the reaction is separated into a gas phase and a liquid phase by a gas-liquid separator, wherein the gas phase is pressurized and recycled. The liquid phase (long-chain alkane) flows out of the device. The operating conditions and reaction results are shown in Table 2.

[0089] Table 2

[0090]

[0091]

[0092] It can be seen from the data in Tables 1 and 2 that Examples 1 to 3 of the present invention use oxygen-containing solvents in hydrogenation pretreatment, so that the reaction conversion rate is high, the selectivity is high (100%), the purity of the obtained product is high, and the overall clarity is transparent; at the same time, the oxygen-containing solvent in the product is separated and removed to avoid its influence on the subsequent process, and the separated solvent is effectively recovered (95%, 92%, 94%).

[0093] In contrast, the hydrogenation pretreatment of the comparative example did not use a solvent, and the reaction conversion rate and selectivity were low (82%, 39%), and the purity of the obtained product was low, and the whole product was turbid brown-black and viscous. It is further shown that the method of one embodiment of the present invention has a high conversion rate, high selectivity, and high product purity for hydrogenation pretreatment, while saving raw materials.

[0094] Unless otherwise defined, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0095] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments, but is only limited by the claims.

Claims

1. A method for treating an intermediate product of a sugar platform compound to prepare a long-chain alkane, comprising: The solid intermediate product, the sugar platform compound condensation product, is mixed with an oxygen-containing solvent and then subjected to hydrogenation pretreatment; Separating the hydrogenation pretreated material into gas and liquid to obtain a liquid mixture; as well as The oxygen-containing solvent is separated from the liquid mixture, so that the solid intermediate product of the sugar platform long-chain alkane is continuously converted into a liquid intermediate product, so that the solid intermediate product is continuously hydrogenated and the solvent is prevented from participating in the subsequent hydrodeoxygenation process. Wherein, the sugar platform compound condensation product is prepared by an aldol condensation reaction between a compound of formula (1) and a compound of formula (2) or formula (3); Formula (1) Formula (2) Formula (3) R1 is selected from -H, -CH2OH, -CH2OCH3, -CH2OCH2CH3, -CH2OC3H7 or -CH2OC4H9; R2 is selected from -H, -CH3, -CH2CH3, -C3H7 or -C4H9; R3 and R4 are independently selected from -CH3, -CH2CH3, -C3H7 or -C4H9.

2. The method according to claim 1, comprising preheating the mixture of the sugar platform compound condensation product and the oxygen-containing solvent, and then performing the hydrogenation pretreatment after the preheating.

3. The method according to claim 1, wherein: The oxygen-containing solvent is selected from one or more of methanol, ethanol, acetone and tetrahydrofuran.

4. A processing device for the processing method according to any one of claims 1 to 3, comprising: mixer; a hydrogenation reactor, connected to the mixer; a first separator, connected to the hydrogenation reactor; as well as a second separator, connected to the first separator; The hydrogenation reactor is connected to the first separator through the bottom; The hydrogenation reactor is also connected to the top of the first separator via the top, so that a hydrogen circulation passage is formed between the hydrogenation reactor and the first separator; The second separator is communicated with the mixer, so that an oxygen-containing solvent circulation passage is formed between the second separator and the mixer.

5. The device according to claim 4, comprising heating components respectively connected to the mixer and the hydrogenation reactor.

6. The device according to claim 4, wherein: A condenser is provided on the oxygen-containing solvent circulation passage.

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