Preparation method of isododecane solvent naphtha

Abstract

The invention provides a preparation method of isododecane solvent oil. The preparation method comprises the following steps: 1) removing an oxygen-containing compound from isododecene through an adsorption tank; 2) reacting isododecene with hydrogen in the pre-hydrogenation reactor to remove alkadiene; 3) carrying out hydrodeoxygenation, olefin saturation, aromatic hydrocarbon saturation and other reactions in the hydrofining reactor; and 4) separating the reaction product to obtain a high-purity isododecane solvent naphtha product. The isoparaffin solvent oil obtained by the method is high in yield, high in isoparaffin content and high in isobranching degree. The content of aromatic hydrocarbon, sulfur and nitrogen compounds in the product is extremely low. By arranging the pre-hydrogenation reactor, the coking of the hydrofining reactor is effectively reduced; by arranging the circulating pump, the temperature difference in the reactor is effectively reduced; by arranging the reaction effluent / pre-hydrogenation reaction feeding heat exchanger and the reaction effluent / hydrofining reaction feeding heat exchanger, reaction heat is effectively utilized, arrangement of a reaction feeding heating furnace is omitted, and the operation energy consumption of the device is reduced.

Description

Technical Field

[0001] This invention relates to the field of petrochemical technology, specifically to a method for preparing isomeric dodecane solvent oil. Background Technology

[0002] Solvent oils, as one of the five major categories of petroleum products, have a wide range of applications and market demand is constantly increasing. Based on hydrocarbon composition, they are classified into n-alkane solvent oils, naphthenic solvent oils, and isoalkane solvent oils. High-end isoalkane solvent oils are mainly products of foreign companies, such as Idemitsu IP CLEAN series, ExxonMobil ISOPAR series, Shell SHELLSOL series, and INEOS IDD-IHD series.

[0003] Iso-dodecane is a highly branched hydrocarbon product characterized by its clear, colorless, and odorless appearance, harmlessness to the human body, and easy biodegradability. It evaporates very quickly and exhibits excellent solubility and compatibility with various active ingredients and oils, making it widely used in skincare and haircare products. Furthermore, its highly branched molecular structure gives it high anti-knock properties and excellent solubility, making it widely used in high-performance engine fuels and lubricant additives. It is a safe and environmentally friendly solvent oil.

[0004] The main production processes for isoalkane solvent oils include: alkylation, Fischer-Tropsch synthesis, and isobutene C4 polymerization. Alkylation involves combining isobutane with light olefins to produce isoalkane. The isoalkane solvent oil is then obtained through hydrogenation and re-distillation. This method generally yields isoalkane solvent oils within the gasoline fraction range, but producing higher fractions is more difficult.

[0005] Chinese patent CN101921621A discloses a method for producing isomeric alkane solvent oil. Using distillate oil or light de-oil as raw materials, a combined process of hydrotreating, hydroisomerization, and supplementary hydrorefining is employed to produce isomeric solvent oil. This method can yield high-quality isomeric alkane solvent oil products with sulfur and nitrogen content below 50 ppm, but the product yield is low, only slightly above 40%, and the aromatic hydrocarbon content in the isomeric alkane solvent oil is >0.03%, failing to meet the requirements for green and clean solvent oil.

[0006] Currently, the Fischer-Tropsch synthesis process, primarily based on coal-to-oil technology, is the main method used in China. Chinese patent CN107400535A discloses a method for producing isoparaffin solvent oil from Fischer-Tropsch naphtha. This method involves converting Fischer-Tropsch naphtha into isoparaffins through an alcohol halogenation reaction, polymerization reaction, and hydrogenation reaction. The yield of the isoparaffin solvent oil depends on the olefin content in the Fischer-Tropsch naphtha, which is only above 20%, resulting in a low overall yield. High-quality raw materials are required, with α-olefin content ≥85%. Furthermore, the isoparaffin content decreases significantly when the final boiling point is increased to 200℃. Chinese patent CN111471487A discloses a process for preparing isoparaffin solvent oil by separating Fischer-Tropsch crude wax or Fischer-Tropsch crude wax and naphtha as raw materials. This process uses molecular sieve adsorption dewaxing to separate n-alkanes and non-n-alkanes, yielding high-purity isoparaffin solvent oil. However, this method yields low yields of isomeric alkane solvent oils and has a low degree of isobranching.

[0007] The production of isobutylene C4 polymerization to produce isoalkyl solvent oil: Isobutylene is polymerized from naphtha cracking, typically using a two-step process including oligomerization and hydrogenation. The isobutylene trimer (TIB) produced by isobutylene oligomerization is further hydrogenated to prepare isododecane. In this technology, oligomerization and hydrogenation are usually carried out in two different reactors. The isobutylene oligomerization reaction has low selectivity for triisobutylene, and low-value-added products such as isooctane are generated as byproducts. The technology involved in this invention patent uses isododecane, a byproduct of isononanol production, as a raw material to prepare high-purity isododecane solvent oil via hydrogenation.

[0008] Chinese patent CN114163286A discloses a method for producing isododecane and co-producing triisobutylene through the oligomerization and hydrogenation of isobutylene. The reaction tower is filled with an oligomerization catalyst and a hydrogenation catalyst, respectively. The raw material isobutylene is polymerized through the oligomerization catalyst to produce diisobutylene and triisobutylene. The oligomerization product is separated and recycled back into the reaction tower for further reaction, yielding triisobutylene in the bottom of the tower. A portion of the oligomerized triisobutylene is then reacted with the hydrogenation catalyst within the reaction tower to generate isododecane. This technology allows the oligomerization and hydrogenation reactions to occur in the same reactor, but the selectivity for triisobutylene is only around 70-80%, and the yield of isododecane is relatively low.

[0009] The hydrogenation of isododecene, a byproduct of isobutene production in the production of isononol, to produce isoalkanes is essentially still a C4 polymerization of isobutene. Chinese patent CN 112745939A discloses a method for producing isoalkanes as solvents by hydrogenation of isononol production byproducts. In this method, the hydrogenation product after hydrogenation saturation of isoolefins is subjected to gas-liquid separation and then distillation to obtain the isoalkanes as solvent products. However, this method suffers from drawbacks because the isododecene produced by the isononol unit contains some dienes, which are prone to coking at the reaction temperature, reducing catalyst life and unit operating cycle. Furthermore, the separation and fractionation process of the reaction products is relatively complex, resulting in excessively high equipment investment. Summary of the Invention

[0010] To overcome the shortcomings of the prior art, the present invention provides a method for producing isododecane solvent oil. The present invention can solve the problem of coking in the reaction system during the hydrorefining of isododecene in the prior art, extend the operation cycle of the equipment, simplify the fractionation system, and reduce the energy consumption and investment of the equipment.

[0011] This invention utilizes the hydrogenation of isododecene to produce isododecane solvent oil, which features high raw material purity, extremely low levels of harmful impurities such as sulfur, nitrogen, and aromatics, and higher quality and safety of the resulting isododecane solvent oil. This invention also increases the added value of byproducts from the isononanol plant.

[0012] To achieve the above-mentioned objectives, this invention provides a method for preparing isomeric dodecane solvent oil, the specific technical solution of which is as follows:

[0013] A method for preparing an isomeric dodecane solvent oil, characterized by comprising the following steps:

[0014] 1) The raw material isododecene is introduced into the feed buffer tank after oxygen-containing compounds are removed by the feed adsorption tank and solid particles are removed by the feed filter.

[0015] 2) The isododecene from step 1) is pressurized by the hydrogenation feed pump and mixed with circulating hydrogen. After being preheated by the reaction effluent / pre-hydrogenation reaction feed heat exchanger, it enters the pre-hydrogenation reactor.

[0016] 3) The mixed feedstock is de-olefinized in the pre-hydrogenation reactor. The pre-hydrogenation reaction product is mixed with high-resolution circulating oil and circulating hydrogen, and then sent to the hydrorefining reactor after heat exchange with the reaction product oil.

[0017] 4) The reaction products from the bottom of the hydrorefining reactor are heat exchanged and cooled before entering the high-pressure separator;

[0018] 5) The high-pressure gas generated at the top of the high-pressure separator is pressurized by the circulating hydrogen compressor and then divided into two paths. One path is used as quench hydrogen to control the temperature of each bed in the reactor, and the other path is mixed with fresh hydrogen from outside the unit to become mixed hydrogen. The reaction oil generated at the bottom of the high-pressure separator is partially used as circulating oil and pressurized to mix with the pre-hydrogenated reaction products. The remaining reaction oil is sent to the fractionation system.

[0019] 6) After hydrogenation, the reaction-generated oil exchanges heat with the product extracted from the bottom of the fractionation tower and then enters the fractionation tower. The oil and gas at the top of the tower are condensed, and the reflux portion is pumped back to the top of the tower. The light component product is further cooled and then exits the unit, and a small amount of dry gas is sent out of the unit. The product generated at the bottom of the tower, isomeric dodecane solvent oil, is pressurized and exchanged heat with the feed, and then further cooled and exits the unit.

[0020] The present invention discloses a method for preparing isomeric dodecane solvent oil, which is further characterized in that: both the pre-hydrogenation reactor and the hydrorefining reactor are fixed-bed reactors.

[0021] The present invention discloses a method for preparing isomeric dodecane solvent oil, further characterized in that: the pre-hydrogenation reactor is filled with a diene-removing catalyst.

[0022] The present invention discloses a method for preparing isomeric dodecane solvent oil, which is further characterized in that: the inlet temperature of the pre-hydrogenation reactor is 40-120°C and the reaction pressure is 2.0-8.0 MPaG.

[0023] The present invention discloses a method for preparing isomeric dodecane solvent oil, which is further characterized in that: the pre-hydrogenation reactor is a liquid-phase hydrogenation reaction, and the feed hydrogen-to-oil ratio is not less than 10.

[0024] This invention discloses a method for preparing isomeric dodecane solvent oil, further characterized in that: the volume hourly space velocity (VHSV) of the pre-hydrogenation reaction feed relative to the catalyst is 0.6–4.0 h⁻¹. -1 Preferably 0.8–1.5 h -1 .

[0025] The present invention discloses a method for preparing isomeric dodecane solvent oil, which is further characterized in that the temperature rise of the bed in the pre-hydrogenation reactor does not exceed 5°C.

[0026] The present invention discloses a method for preparing isomeric dodecane solvent oil, which is further characterized in that: the hydrorefining reactor is filled with a hydrorefining catalyst.

[0027] The present invention discloses a method for preparing isomeric dodecane solvent oil, which is further characterized in that: the inlet temperature of the hydrorefining reactor is 180-300°C and the reaction pressure is 2.0-8.0 MPaG.

[0028] The present invention discloses a method for preparing isomeric dodecane solvent oil, which is further characterized in that: the hydrorefining reaction feed is a gas-liquid two-phase feed.

[0029] This invention discloses a method for preparing isomeric dodecane solvent oil, further characterized in that: the volume hourly space velocity (VHSV) of the hydrorefining reaction feed relative to the catalyst is 0.6–4.0 h⁻¹. -1 Preferably 0.8–1.5 h -1 .

[0030] The present invention discloses a method for preparing isomeric dodecane solvent oil, which is further characterized in that: the heat required for the feed of the pre-hydrogenation reactor and the hydrorefining reactor is provided entirely by heat exchange with the hydrogenation reaction products, and no reaction feed heating furnace is provided.

[0031] The present invention discloses a method for preparing isomeric dodecane solvent oil, further characterized in that: a circulating oil pump is provided at the bottom of the high-pressure separator.

[0032] The present invention discloses a method for preparing isomeric dodecane solvent oil, which is further characterized in that the ratio of the mass flow rate of the high-resolution circulating oil to the mass flow rate of the fresh raw material is 1 to 3:1.

[0033] The present invention discloses a method for preparing isomeric dodecane solvent oil, further characterized in that: the top temperature of the fractionation column is 180-200℃, the pressure is 0.1-0.15 MPaG, and the bottom temperature is 230-250℃.

[0034] The present invention discloses a method for preparing isomeric dodecane solvent oil, further characterized in that: the heat of the reboiler at the bottom of the fractionation tower is provided by an electric heater or heat transfer oil.

[0035] The raw material for this invention is isododecene. In addition to conventional feed filtration, a feed adsorption tank is provided to remove water and oxygen-containing compounds from the raw material. After exiting the feed buffer tank, the isododecene is pressurized by a hydrogenation feed pump and mixed with circulating hydrogen. It is then preheated and enters a pre-hydrogenation reactor to remove dienes from the raw material. The pre-hydrogenation reaction effluent is mixed with circulating oil and circulating hydrogen and then undergoes hydrodeoxygenation, olefin saturation, and aromatic saturation reactions in a hydrorefining reactor. After heat exchange, cooling, and gas-liquid separation, the reaction products are used as circulating hydrogen. A portion of the high-grade oil is returned to the reaction system as circulating oil, and the remaining high-grade oil enters a fractionation tower for product purification. High-purity isododecane solvent oil is obtained from the bottom oil of the tower.

[0036] The beneficial effects of this invention are as follows:

[0037] 1) The pre-hydrogenation reactor is filled with a diene removal catalyst, which can remove dienes from the feedstock to protect the subsequent reaction system and extend the catalyst life and the operation cycle of the unit.

[0038] 2) The hydrorefining reactor is filled with refining catalyst. Isododecene, hydrogen and catalyst release a large amount of reaction heat in the hydrorefining reactor. By setting up a reaction effluent / pre-hydrogenation reaction feed heat exchanger and a reaction effluent / hydrorefining reaction feed heat exchanger, the reaction heat can be effectively utilized, the setting of the reaction feed heater can be eliminated, the energy consumption of the unit operation can be reduced, carbon emissions can be reduced, and investment can be saved.

[0039] 3) Setting the fractionation tower as an atmospheric pressure tower can reduce the bottom operating temperature of the tower, avoid excessive temperature causing deterioration of solvent oil products, and at the same time reduce the heat load of the bottom reboiler, thereby reducing the energy consumption of the unit.

[0040] 4) The isoparaffin solvent oil obtained by this method has a high yield, high content of isoparaffins, and high degree of isobranching. The content of aromatics, sulfur and nitrogen compounds in the product is extremely low.

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this does not limit the scope of the invention. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the preparation method of an isomeric dodecane solvent oil according to the present invention.

[0043] The reference numerals in the figure are: 1-Feed buffer tank; 2-Hydrogenation feed pump; 3-Reaction effluent / pre-hydrogenation reaction feed heat exchanger; 4-Pre-hydrogenation reactor; 5-Reaction effluent / hydrogenation refining reaction feed heat exchanger; 6-Hydrogenation refining reactor; 7-Reaction effluent air cooler; 8-High-pressure separator; 9-Circulating oil pump; 10-Circulating hydrogen compressor; 11-Fracturing column feed heater; 12-Fracturing column; 13-Fracturing column top air cooler; 14-Fracturing column top reflux tank; 15-Fracturing column bottom pump; 16-Fracturing column top reflux pump; 17-Iso-dodecane product air cooler; 18-Light component water cooler. Detailed Implementation

[0044] The implementation of the technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0045] As attached Figure 1As shown, after isododecene comes out of the feed buffer tank 1, it is pressurized by the hydrogenation feed pump 2 and mixed with circulating hydrogen. After being preheated to the temperature required for the diene removal reaction by the reaction effluent / pre-hydrogenation reaction feed heat exchanger 3, it enters the pre-hydrogenation reactor 4, where dienes are removed from the feed under the action of a catalyst. The pre-hydrogenation reaction effluent, after being mixed with circulating oil and circulating hydrogen, is heated by the reaction effluent / hydrorefining reaction feed heat exchanger 5 and then enters the hydrorefining reactor 6. Under the action of the catalyst, reactions such as hydrodeoxygenation, olefin saturation, and aromatic saturation are carried out. The reaction products flow out from the bottom of the hydrorefining reactor and are cooled by the reaction effluent / hydrorefining reaction feed heat exchanger 5, the reaction effluent / pre-hydrogenation reaction feed heat exchanger 3, and the reaction effluent air cooler 7 before entering the high-pressure separator 8 for gas-liquid separation. The high-separation gas enters the circulating hydrogen compressor 10 for pressurization and is divided into two paths. One path is used as quench hydrogen to control the temperature of the second bed in the reactor, and the other path is mixed with fresh hydrogen from outside the unit to become mixed hydrogen. Part of the high-separation oil is pressurized by the circulating oil pump 9 and mixed with the pre-hydrogenation product oil before entering the hydrorefining reactor. The remaining part is depressurized and enters the fractionation system.

[0046] Hydrogenated isododecane from the reaction section is heated by the feed heater 11 and then enters the fractionation column 12, which is equipped with a reboiler at the bottom. The bottom product, isododecane, is pressurized by the bottom pump 15, exchanges heat with the column feed, and then enters the isododecane product air cooler 17 for cooling before exiting the unit. The top product is condensed by the top air cooler 13 and enters the top reflux tank 14. The light component flowing out of the tank is pressurized by the top reflux pump 16, and part of it is used as top reflux, while the remainder is further cooled by the light component water cooler 18 before being sent out of the unit. A small amount of dry gas from the top is also sent out of the unit.

[0047] In this embodiment, the hydrogen-to-oil ratio in the pre-hydrogenation reaction feed is not less than 10, and the hydrogen-to-oil ratio in the hydrorefining reaction feed is not less than 600. The ratio of the circulating oil mass flow rate to the fresh feed mass flow rate is 1–3. Due to the installation of a circulating pump, the temperature difference within the hydrorefining reactor is not greater than 35°C. The reaction temperature in the pre-hydrogenation reactor is 40–120°C, and the reaction pressure is 2.0–8.0 MPaG. The reaction temperature in the hydrorefining reactor is 180–300°C, and the reaction pressure is 2.0–8.0 MPaG. The top temperature of the fractionation column is 180–200°C, the pressure is 0.1–0.15 MPaG, and the bottom temperature is 230–250°C.

[0048] Table 1 shows the product specifications for this embodiment.

[0049]

[0050] Compared with high-end Japanese solvent oil products, the isomeric dodecane solvent oil products obtained in the above embodiments have comparable product indicators to Idemitsu IP 1620, which greatly improves the added value of the products.

[0051] The above are merely typical embodiments of the present invention. Those skilled in the art can make appropriate modifications and improvements based on them, but they are substantially the same as the present invention and also fall within the protection scope of the present invention.

Claims

1. A method for preparing an isomeric dodecane solvent oil, characterized in that... Includes the following steps: 1) The raw material isododecene is introduced into the feed buffer tank after oxygen-containing compounds are removed by the feed adsorption tank and solid particles are removed by the feed filter. 2) The isododecene from step 1) is pressurized by the hydrogenation feed pump and mixed with circulating hydrogen. After being preheated by the reaction effluent / pre-hydrogenation reaction feed heat exchanger, it enters the pre-hydrogenation reactor. 3) The mixed feedstock is de-olefinized in the pre-hydrogenation reactor. The pre-hydrogenation reaction product is mixed with high-resolution circulating oil and circulating hydrogen, and then sent to the hydrorefining reactor after heat exchange with the reaction product oil. 4) The reaction products from the bottom of the hydrorefining reactor are heat exchanged and cooled before entering the high-pressure separator; 5) The high-pressure gas generated at the top of the high-pressure separator is pressurized by the circulating hydrogen compressor and then divided into two paths. One path is used as quench hydrogen to control the temperature of each bed in the reactor, and the other path is mixed with fresh hydrogen from outside the unit to become mixed hydrogen. The reaction oil generated at the bottom of the high-pressure separator is partially used as circulating oil and pressurized to mix with the pre-hydrogenated reaction products. The remaining reaction oil is sent to the fractionation system. 6) After hydrogenation, the reaction-generated oil exchanges heat with the product extracted from the bottom of the fractionation tower and then enters the fractionation tower. The oil and gas at the top of the tower are condensed, and the reflux portion is pumped back to the top of the tower. The light component product is further cooled and then exits the unit, and a small amount of dry gas is sent out of the unit. The product generated at the bottom of the tower, isomeric dodecane solvent oil, is pressurized and exchanged heat with the feed, and then further cooled and exits the unit.

2. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: Both the pre-hydrogenation reactor and the hydrorefining reactor are fixed-bed reactors.

3. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The pre-hydrogenation reactor is filled with a dediolefin catalyst.

4. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The inlet temperature of the pre-hydrogenation reactor is 40–120°C, and the reaction pressure is 2.0–8.0 MPa.

5. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The pre-hydrogenation reactor is a liquid-phase hydrogenation reaction, and the hydrogen-to-oil ratio in the feed is not less than 10.

6. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The volume hourly space velocity (VHSV) of the pre-hydrogenation reaction feed relative to the catalyst is 0.6–4.0 h⁻¹, preferably 0.8–1.5 h⁻¹.

7. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The temperature rise of the bed in the pre-hydrogenation reactor does not exceed 5°C.

8. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The hydrogenation refining reactor is filled with a hydrogenation catalyst.

9. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The inlet temperature of the hydrorefining reactor is 180–300°C, and the reaction pressure is 2.0–8.0 MPa.

10. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The feed for the hydrogenation refining reaction is a gas-liquid two-phase feed.

11. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The volume hourly space velocity (VHSV) of the hydrorefining reaction feed relative to the catalyst is 0.6–4.0 h⁻¹. -1 .

12. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The heat required for the feed to the pre-hydrogenation reactor and the hydrorefining reactor is provided entirely through heat exchange with the hydrogenation reaction products, without the need for a reaction feed heating furnace.

13. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The high-pressure separator is equipped with a circulating oil pump at the bottom.

14. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The ratio of the mass flow rate of the high-resolution circulating oil to the mass flow rate of the fresh feedstock is 1 to 3:

1.

15. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The distillation column has a top temperature of 180–200°C, a pressure of 0.1–0.15 MPaG, and a bottom temperature of 230–250°C.

16. The method for preparing isomeric dodecane solvent oil according to claim 1, characterized in that: The heat for the reboiler at the bottom of the fractionation tower is provided by an electric heater or heat transfer oil.

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