Self-reaction deep deoxygenation method for fischer-tropsch process light oil

Abstract

Disclosed in the present invention is a self-reaction deep deoxygenation method for Fischer-Tropsch Process light oil, comprising the following steps: feeding a Fischer-Tropsch Process light fraction oil feedstock into a crude deoxygenation reaction tower containing a catalyst, in the tower light oxygen-containing compounds undergo self-reaction to produce oxygen-rich heavy substances having a distillation range above 160°C; and feeding a crude deoxygenation reaction tower product into a heavy-cut distillation tower for heavy fraction separation, an oxygen-rich heavy oil being discharged from the bottom of the tower, feeding a tower top light fraction oil into a deep deoxygenation adsorption tower containing an adsorbent, after deep deoxygenation, obtaining a Fischer-Tropsch Process light fraction oil with an oxide concentration of less than 0.1 μg / g from the bottom of the adsorption tower. The present invention achieves deep removal of oxides from the Fischer-Tropsch Process light fraction oil in a three-tower series configuration with low energy consumption and low costs.

Description

A method for self-reactive deep deoxygenation of Fischer-Tropsch synthesis light oil Technical Field

[0001] This invention relates to the field of chemical engineering and technology, and in particular to a self-reactive deep deoxygenation method for Fischer-Tropsch synthesis light oil. Background Technology

[0002] The Fischer-Tropsch synthesis reaction is a synthetic reaction that uses syngas as a raw material to produce a large amount of hydrocarbon organic compounds under the action of a catalyst. Fischer-Tropsch synthetic oils can be used to produce diesel, Fischer-Tropsch waxes, lubricating oils, solvent oils, and various olefin products and other chemical products. However, Fischer-Tropsch synthetic oils also contain 5% to 15% by mass of organic oxygen-containing compounds, mainly alcohols, aldehydes, acids, esters, and ketones. These oxygen-containing compounds can cause corrosion to equipment and create difficulties in downstream product processing. For example, in the linear α-olefin polymerization process, they can reduce catalyst activity, affect catalyst performance, and even lead to catalyst poisoning and deactivation. These oxygen-containing compounds can also affect the properties of the products, such as affecting the light stability of Fischer-Tropsch waxes, giving them a certain odor, reducing product quality, and limiting their application. The content of oxygen-containing compounds in naphtha directly affects the quality of downstream chemical products. In addition, the presence of oxygen-containing compounds increases the viscosity of the oil, darkens its color, and makes it easier to form gums, affecting the oxidation stability of diesel and placing higher demands on the storage and utilization of diesel. Removing oxygen-containing compounds from Fischer-Tropsch synthetic oils is essential.

[0003] Currently, the main methods for removing oxygen-containing compounds from Fischer-Tropsch synthetic oils include hydrodeoxygenation, chemical removal, liquid-liquid extraction, distillation, and physical adsorption. For example, Chinese invention patent CN111718746A discloses a method for deoxygenating and refining Fischer-Tropsch synthetic oils. The method involves distilling the Fischer-Tropsch synthetic oils under atmospheric and vacuum conditions to obtain a first fraction, a second fraction, and a third fraction; (2) performing a first extraction on the first fraction using a methanol aqueous solution to obtain extract phase 1 and raffinate phase 1; performing a second extraction on the second fraction using an ethanol aqueous solution to obtain extract phase 2 and raffinate phase 2; and performing a third extraction on the third fraction using an ethylene glycol ether aqueous solution to obtain extract phase 3 and raffinate phase 3; (3) washing the raffinate phase 1, raffinate phase 2, and raffinate phase 3 with water to obtain deoxygenated and refined Fischer-Tropsch synthetic oils. This method not only maintains the content of α-olefins during the removal of oxygenated compounds, but also reduces the content of oxygenated compounds in the deoxygenated and refined Fischer-Tropsch synthetic oil to below 100 ppm, and has a high oil recovery rate.

[0004] For example, Chinese invention patent CN114907878A discloses a method for removing oxygen-containing compounds from Fischer-Tropsch synthetic oil through adsorption-distillation coupling. This method involves feeding the Fischer-Tropsch synthetic oil feedstock into an adsorption-distillation separation unit, which consists of one or more adsorption-distillation columns. Under the action of deoxygenated adsorption-distillation packing material inside the adsorption-distillation columns, oxygen-containing compounds are deeply removed. A deeply deoxygenated light fraction is obtained at the top of the column, while a heavy fraction enriched with oxygen-containing compounds is obtained at the bottom. The side stream of the adsorption-distillation column can be used to collect the middle fraction of Fischer-Tropsch synthetic oil as needed, which is then fed into subsequent adsorption-distillation columns for further oxygen-containing compound removal from other middle fraction oil products. This invention couples adsorption and distillation processes, eliminating the need for desorbents, simplifying the process flow, reducing industrialization costs, and simultaneously achieving deep removal of oxygen-containing compounds and fractionation in Fischer-Tropsch synthetic oil. Furthermore, the deoxygenated adsorption-distillation packing material in this invention has a long service life, low distillation energy consumption, and high oxygen-containing compound removal efficiency.

[0005] For example, Chinese invention patent CN114479914A discloses a method for removing oxygen-containing compounds from Fischer-Tropsch synthetic oil, belonging to the field of Fischer-Tropsch oil treatment technology. This method includes: removing oxygen-containing compounds from the Fischer-Tropsch synthetic oil to be treated using sulfonic acid resin in a fixed-bed reactor; the weight ratio of sulfonic acid resin to the Fischer-Tropsch synthetic oil to be treated is 1:100-200. By utilizing the reaction between sulfonic acid resin and Fischer-Tropsch synthetic oil, oxygen-containing compounds can be removed from the Fischer-Tropsch synthetic oil without loss of straight-chain olefins, while simultaneously generating additional straight-chain olefins, significantly increasing the olefin content of the oil. Furthermore, this method helps extend the service life of the sulfonic acid resin, generates fewer byproducts, has minimal impact on olefin purity, consumes less energy, and is highly economical.

[0006] As can be seen from the existing technologies above, the current deoxygenation technology mainly relies on extraction, adsorption, and direct reaction of oxides, which has a limited degree of deoxygenation. There is no technology that can completely remove oxides from light distillate oils synthesized from Fischer-Tropsch synthesis. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method for deep deoxygenation of Fischer-Tropsch synthesis light oil through self-reaction.

[0008] The present invention is achieved by the following technical solution.

[0009] A method for self-reactive deep deoxygenation of Fischer-Tropsch synthesis light oil includes the following steps:

[0010] The Fischer-Tropsch light distillate feedstock is fed into a crude deoxygenation reaction tower containing a catalyst. Inside the tower, light oxygen-containing compounds react to generate oxygen-enriched heavy products with a distillation range greater than 160°C. The product from the crude deoxygenation reaction tower is fed into a heavy fraction distillation tower for heavy fraction removal. The oxygen-enriched heavy oil is discharged from the bottom of the tower, while the light distillate oil at the top of the tower is fed into a deep deoxygenation adsorption tower containing an adsorbent. After deep deoxygenation, Fischer-Tropsch light distillate oil with an oxide concentration of less than 0.1 μg / g is obtained from the bottom of the adsorption tower.

[0011] By adopting the above technical solution, the oxide content of the light distillate oil at the top of the heavy distillation column is reduced by more than 95% compared with the Fischer-Tropsch synthesis light distillate oil feedstock. After processing by the process of this invention, the oxide content of the final product is less than 0.1 μg / g. This invention achieves deep removal of oxides from Fischer-Tropsch synthesis light distillate oil through three columns connected in series, with low energy consumption and low cost.

[0012] Furthermore, the distillation range of the Fischer-Tropsch synthesis light distillate feedstock is 30°C to 160°C, and the oxygen content of the feedstock is controlled to be less than 10%.

[0013] Furthermore, the active component of the catalyst in the crude deoxygenation reaction tower has a mass content greater than 85%, and the active component is selected from Beta molecular sieve or Y molecular sieve.

[0014] Furthermore, the crude deoxidation reaction tower operates at a temperature of 80–250℃, a pressure of 0.1–2.0 MPa, and a volume hourly space velocity of 0.05–1 h⁻¹. -1 .

[0015] Furthermore, the heavy distillation column is a reduced pressure column with an absolute pressure of 5–100 kPa, a top temperature of 10–120°C, a bottom temperature of 100°C–140°C, a theoretical plate number of 40–60, and Raschig rings and / or Pall rings as packing.

[0016] Furthermore, the adsorbent active component in the deep deoxygenation adsorption tower has a mass content of more than 90%, and the active component is selected from 13X molecular sieve.

[0017] Furthermore, the deep deoxygenation adsorption tower has an adsorption temperature of 30–100℃, a height-to-diameter ratio of 2–10, and an adsorption volume space velocity of 0.2–4 h⁻¹. -1 The adsorption pressure is 0.1–2.0 MPa.

[0018] This application has the following beneficial effects.

[0019] Compared with extraction and adsorption methods, this invention has the advantages of low energy consumption, low adsorbent consumption, and low cost. It can achieve deep removal of oxides from Fischer-Tropsch synthesis light distillate oils, reduce the industrialization cost of deoxygenation of Fischer-Tropsch synthesis light distillate oils, and the catalyst and adsorbent in this invention have a long service life and high deoxygenation efficiency, providing a more economical and simple method for the processing and utilization of Fischer-Tropsch synthesis light distillate oils and the comprehensive utilization of downstream olefins. Attached Figure Description

[0020] Figure 1 is a process flow diagram of the present invention;

[0021] Among them, 1. crude deoxygenation reaction tower; 2. heavy distillation tower; 3. deep deoxygenation adsorption tower. Detailed Implementation

[0022] The present patent application will be further described below with reference to the embodiments.

[0023] Unless otherwise specified, the experimental methods used in the following preparation examples and embodiments are conventional methods.

[0024] A method for self-reactive deep deoxygenation of Fischer-Tropsch synthesis light oil includes the following steps:

[0025] The Fischer-Tropsch light distillate feedstock has a distillation range of 30℃ to 160℃. First, the Fischer-Tropsch light distillate is fed into a crude deoxygenation reaction tower 1 containing a catalyst. In the tower, the oxides of alcohols, aldehydes, acids, esters, ketones, etc., contained in the Fischer-Tropsch light distillate undergo a series of reactions between oxides, including acetal condensation, aldol condensation, and etherification, generating an oxygen-rich heavy product with a distillation range greater than 160℃. The product from the crude deoxygenation reaction tower is then fed into a heavy distillation tower 2 for heavy removal treatment. The oxygen-rich heavy oil is discharged from the bottom of the tower, and the oxide content of the light distillate oil at the top of the tower is reduced by more than 95% compared to the Fischer-Tropsch light distillate feedstock. The light distillate oil at the top of the tower is then fed into a deep deoxygenation adsorption tower 3 containing an adsorbent. After deep deoxygenation, a Fischer-Tropsch light distillate oil with an oxide concentration of less than 0.1 μg / g is obtained from the bottom of the adsorption tower.

[0026] Example 1

[0027] The experiment was conducted using raw materials from a certain company. The raw material data are shown in Tables 1.1 and 1.2.

[0028] Table 1.1 Hydrocarbon composition of Fischer-Tropsch synthesis light distillate feedstock

[0029] Table 1.2 Distillation Range of Fischer-Tropsch Synthesis Light Distillate Oil Feedstock

[0030] The Fischer-Tropsch synthesis light distillate oil was fed into a crude deoxygenation reactor, which was loaded with commercially available catalyst A1. The reaction temperature was 120°C, the reaction pressure was 0.5 MPa, and the reaction volume hourly space velocity was 0.5 h⁻¹. -1The physical properties of catalyst A1 are shown in Table 1.3.

[0031] Table 1.3 Properties of Catalyst A1

[0032] The hydrocarbon composition data of the products obtained from the Fischer-Tropsch synthesis light distillate oil through a crude deoxygenation reactor are shown in Table 1.4.

[0033] Table 1.4 Hydrocarbon composition of products from the crude deoxidation reaction tower

[0034] The product from the crude deoxygenation reaction tower enters a heavy component separation distillation column for heavy component separation. The distillation column is packed with Raschig rings and has 45 trays. By controlling the column pressure to an absolute pressure of 15 kPa, the reboiler temperature to 140°C, and the top temperature to vary from 10 to 120°C during distillation, the separation of light and heavy components in the oil product is achieved. The hydrocarbon composition of the top product is shown in Table 1.5, and the hydrocarbon composition of the reboiler product is shown in Table 1.6. The yield of the top product is 94.5%, and the yield of the reboiler product is 5.5%. The oxide content of the top product is 95.77% lower than that of the Fischer-Tropsch synthesis light distillate feedstock.

[0035] Table 1.5 Hydrocarbon composition of the top product from the distillation column

[0036] Table 1.6 Hydrocarbon composition of the bottom product from the distillation column

[0037] The product from the distillation column top enters a deep deoxygenation adsorption column for further deoxygenation treatment. The adsorption temperature is 35℃ and the adsorption volume space velocity is 0.5 h⁻¹. -1 The adsorption pressure was 0.9 MPa, the height-to-diameter ratio of the adsorption tower was 3, the properties of commercially available adsorbent A2 are shown in Table 1.7, and the hydrocarbon composition of the bottom product of the adsorption tower is shown in Table 1.8. After passing through the deep deoxygenation adsorption tower, the oxide content of the Fischer-Tropsch synthesis light distillate oil was reduced to below 0.1 ug / g.

[0038] Table 1.7 Properties of Adsorbent A2

[0039] Table 1.8 Hydrocarbon composition of the top product from the distillation column

[0040] Example 2

[0041] The experiment was conducted using raw materials from a certain company. The raw material data are shown in Tables 2.1 and 2.2.

[0042] Table 2.1 Hydrocarbon composition of Fischer-Tropsch synthesis light distillate feedstock

[0043] Table 2.2 Distillation Range of Light Distillate Oil Feedstock for Fischer-Tropsch Synthesis

[0044] The Fischer-Tropsch synthesis light distillate oil was fed into a crude deoxygenation reactor, which was loaded with commercially available catalyst B1. The reaction temperature was 170°C, the reaction pressure was 0.6 MPa, and the reaction volume hourly space velocity was 0.8 h⁻¹. -1 The physical properties of catalyst B1 are shown in Table 2.3.

[0045] Table 2.3 Properties of Catalyst B1

[0046] The hydrocarbon composition data of the products obtained from the Fischer-Tropsch synthesis light distillate oil through a crude deoxygenation reactor are shown in Table 2.4.

[0047] Table 2.4 Hydrocarbon composition of products from the crude deoxidation reaction tower

[0048] The product from the crude deoxygenation reaction tower enters a heavy component separation distillation column for heavy component separation. The distillation column is packed with Pall rings and has 53 trays. By controlling the column pressure to an absolute pressure of 12 kPa, the reboiler temperature to 135°C, and the top temperature to vary from 10 to 100°C during distillation, the separation of light and heavy components in the oil product is achieved. The hydrocarbon composition of the top product is shown in Table 2.5, and the hydrocarbon composition of the reboiler product is shown in Table 2.6. The yield of the top product is 94.4%, and the yield of the reboiler product is 5.6%. The oxide content of the top product is 96.29% lower than that of the Fischer-Tropsch synthesis light distillate feedstock.

[0049] Table 2.5 Hydrocarbon composition of the top product from the distillation column

[0050] Table 2.6 Hydrocarbon composition of the bottom product from the distillation column

[0051] The product from the distillation column's top section enters a deep deoxygenation adsorption column for further deoxygenation treatment. The adsorption temperature is 50℃, and the volume hourly space velocity (WHSV) is 0.9 h⁻¹. -1 The adsorption pressure was 0.4 MPa, the height-to-diameter ratio of the adsorption tower was 5, the properties of commercially available adsorbent B2 are shown in Table 2.7, and the hydrocarbon composition of the bottom product of the adsorption tower is shown in Table 2.8. After passing through the deep deoxygenation adsorption tower, the oxide content of the Fischer-Tropsch synthesis light distillate oil was reduced to below 0.1 ug / g.

[0052] Table 2.7 Properties of Adsorbent B2

[0053] Table 2.8 Hydrocarbon composition of the top product from the distillation column

[0054] Example 3

[0055] The experiment was conducted using raw materials from a certain company. The raw material data are shown in Tables 3.1 and 3.2.

[0056] Table 3.1 Hydrocarbon composition of Fischer-Tropsch synthesis light distillate feedstock

[0057] Table 3.2 Distillation Range of Light Distillate Oil Feedstock for Fischer-Tropsch Synthesis

[0058] The Fischer-Tropsch synthesis light distillate oil was fed into a crude deoxygenation reactor, which was loaded with commercially available catalyst C1. The reaction temperature was 210°C, the reaction pressure was 1.2 MPa, and the reaction volume hourly space velocity was 1.0 h⁻¹. -1 The physical properties of catalyst C1 are shown in Table 3.3.

[0059] Table 3.3 Properties of Catalyst C1

[0060] The hydrocarbon composition data of the products obtained from the Fischer-Tropsch synthesis light distillate oil through a crude deoxygenation reactor are shown in Table 3.4.

[0061] Table 3.4 Hydrocarbon composition of products from the crude deoxidation reaction tower

[0062] The product from the crude deoxygenation reaction tower enters a heavy-duty distillation column for heavy component separation. The distillation column packing is a 1:1 mixture of Pall rings and Raschig rings. The column has 57 trays. By controlling the column pressure to an absolute pressure of 15 kPa, the reboiler temperature to 140°C, and the top temperature to vary from 30 to 120°C during distillation, the separation of light and heavy components in the oil product is achieved. The hydrocarbon composition of the top product is shown in Table 3.5, and the hydrocarbon composition of the reboiler product is shown in Table 3.6. The yield of the top product is 94.5%, and the yield of the reboiler product is 5.5%. The oxide content of the top product is 95.24% lower than that of the Fischer-Tropsch synthesis light distillate feedstock.

[0063] Table 3.5 Hydrocarbon composition of the top product from the distillation column

[0064] Table 3.6 Hydrocarbon composition of the bottom product from the distillation column

[0065] The product from the distillation column top enters a deep deoxygenation adsorption column for further deoxygenation treatment. The adsorption temperature is 70℃, the adsorption pressure is 0.6MPa, and the adsorption volume hourly space velocity is 1.1h. -1 The adsorption tower has a height-to-diameter ratio of 8. The properties of the adsorbent C2 are shown in Table 3.7, and the hydrocarbon composition of the bottom product of the adsorption tower is shown in Table 3.8. After passing through the deep deoxygenation adsorption tower, the oxide content of the Fischer-Tropsch synthesis light distillate oil was reduced to below 0.1 ug / g.

[0066] Table 3.7 Properties of Adsorbent C2

[0067] Table 3.8 Hydrocarbon composition of the top product from the distillation column

[0068] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A process for the self-reaction deep deoxygenation of Fischer-Tropsch light oil characterized in that: Includes the following steps: The Fischer-Tropsch light distillate feedstock is fed into a crude deoxygenation reaction tower (1) containing a catalyst. The light oxygen-containing compounds in the tower react to generate oxygen-rich heavy products with a distillation range greater than 160°C. The product from the crude deoxygenation reaction tower is fed into a heavy distillation tower (2) for heavy removal treatment. The oxygen-rich heavy oil is discharged from the bottom of the tower, and the light distillate oil at the top of the tower is fed into a deep deoxygenation adsorption tower (3) containing an adsorbent. After deep deoxygenation, Fischer-Tropsch light distillate oil with an oxide concentration of less than 0.1 μg / g is obtained from the bottom of the adsorption tower.

2. The process for deep deoxygenation of Fischer-Tropsch light oil by self- reaction according to claim 1, characterized in that: The distillation range of the Fischer-Tropsch synthesis light distillate feedstock is 30℃~160℃, and the oxygen content of the feedstock is controlled to be less than 10%.

3. The method according to claim 1, wherein the method is characterized by: The mass content of the active component of the catalyst in the crude deoxygenation reaction tower (1) is greater than 85%, and the active component is selected from Beta molecular sieve or Y molecular sieve.

4. The process for deep deoxygenation of Fischer-Tropsch light oil by self- reaction according to claim 1, characterized in that: The crude deoxidation reaction tower (1) has a reaction temperature of 80-250°C, a reaction pressure of 0.1-2.0 MPa, and a reaction volume space velocity of 0.05-1 h -1 .

5. The process for deep deoxygenation of Fischer-Tropsch light oil by self- reaction according to claim 1, characterized in that: The heavy distillation column (2) is a reduced pressure column with an absolute pressure of 5-100 kPa, a top temperature of 10-120℃, a bottom temperature of 100℃-140℃, a theoretical number of plates of 40-60, and Raschig rings and / or Pall rings as packing.

6. The process for deep deoxygenation of Fischer-Tropsch light oil by self- reaction according to claim 1, characterized by that: The adsorbent active component in the deep deoxygenation adsorption tower (3) has a mass content of more than 90%, and the active component is selected from 13X molecular sieve.

7. The process for deep deoxygenation of Fischer-Tropsch light oil by self- reaction according to claim 1, characterized by that: The adsorption temperature of the deep deoxidization adsorption tower (3) is 30-100℃, the height-diameter ratio of the adsorption tower is 2-10, the adsorption volume space velocity is 0.2-4h -1 , and the adsorption pressure is 0.1-2.0MPa.

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