Catalytic hydrogenation method for producing green renewable diesel oil by recovering energy

Abstract

The invention provides a catalytic hydrogenation method for producing green renewable diesel oil by recovering energy, and relates to the field of biofuel production. According to the present invention, the novel composite reactor is used for the homogeneous hydrogenation pretreatment and the secondary hydrogenation treatment to replace the traditional suspension bed reactor or tubular reactor and fixed bed reactor series connection process, and the composite reactor uses the chemical reaction heat release during the hydrogenation reaction process to heat the reactants so as to achieve the hydrogenation pretreatment and the secondary hydrogenation pretreatment; the waste heat is reasonably utilized, the heat load of the heating furnace is correspondingly saved, the comprehensive energy consumption of the device is reduced, and the production efficiency is high.

Description

Technical Field

[0001] The invention relates to the field of biofuel production, and in particular to a catalytic hydrogenation method for producing green renewable diesel by recovering energy. Background Art

[0002] Green diesel is the second generation of biodiesel under development. Different from the first generation of biodiesel, which has the chemical composition of higher fatty acid methyl ester, green diesel has the chemical composition of higher aliphatic hydrocarbons, which is consistent with the main chemical composition of petroleum mineral diesel. Therefore, green diesel has a greater prospect in replacing mineral diesel. Green diesel is made from raw materials through hydrogenation, isomerization and purification processes. Among all the process links, the hydrogenation process is crucial.

[0003] The chemical reaction of catalytic hydrogenation of oil products is an exothermic reaction. Once the reaction process begins, the heat released by the reaction can maintain the active temperature requirements of the material reaction and there is still a surplus. Therefore, after the material enters the reactor, it is not only no longer necessary to continue heating, but also the heat released by the reaction must be controlled to ensure that the temperature rise in the reactor remains balanced, otherwise excessive heat accumulation will affect the catalyst structure and performance and even cause safety accidents such as burning production equipment. There are generally two ways to control the reaction heat. One is to reduce the feed amount of the reactor to control the amount of reaction heat generated, and the other is to add a heat exchange function to the reactor to remove excess reaction heat. Both of the above methods have certain defects. The former limits the equipment capacity, reduces production efficiency, and has low economic benefits. The latter increases equipment investment and increases the complexity of the production process.

[0004] In the existing process, there are two sources of heat required to heat the materials entering the reactor. One is to use a heat exchanger to indirectly transfer heat from the high-temperature materials carrying the reaction heat after leaving the reactor to the low-temperature raw materials before entering the reactor, so that the raw materials can be initially heated up; the other is to use heating equipment to continue heating the raw materials after the initial heating. However, the heat transfer efficiency of the former will decrease as the temperature difference decreases during the heat transfer process. The residual heat of the high-temperature material is not enough to raise the low-temperature raw materials to the required temperature within the effective time. At this time, heating equipment is needed to continue heating, but the heat loss during the heating process of the heating equipment is large, and the production energy consumption is high.

[0005] It can be seen that in the process of oil hydrogenation reaction, how to control the reaction exotherm and reduce the heating temperature of the raw materials is crucial. Summary of the invention

[0006] The purpose of the present invention is to provide a catalytic hydrogenation method for producing green renewable diesel with energy recovery in view of the deficiencies of the prior art, which at least solves some of the problems existing in the prior art.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] In one aspect, a composite reactor for catalytic hydrogenation comprises a shell and a pipeline reactor disposed inside the shell; a solid catalyst bed is disposed between the shell and the pipeline reactor; wherein,

[0009] The pipeline reactor is a single row of spiral tubes or is composed of parallel straight tube bundles.

[0010] Furthermore, the composite reactor for catalytic hydrogenation also includes: a feed port, a discharge port, an ash discharge port, and a distribution plate; the feed port is arranged at the upper part of the shell and is connected to the pipeline reactor; the discharge port is arranged at the top of the shell; the ash discharge port is arranged at the bottom of the shell; and the distribution plate is arranged at the lower part of the solid catalyst bed.

[0011] On the other hand, a catalytic hydrogenation method for producing green renewable diesel with energy recovery includes hydrogenating crude oil using the above-mentioned composite reactor for catalytic hydrogenation.

[0012] Furthermore, the raw oil is selected from any one of waste oil, vegetable oil and animal oil.

[0013] Further, the hydroprocessing step is:

[0014] (1) The crude oil in the raw material storage tank is pressurized by a pressure pump, mixed with hydrogen, and heated in a reaction heating furnace; then the liquid catalyst in the homogeneous catalyst storage tank is pressurized and injected into the crude oil by a homogeneous catalyst filling pump, and then sent to a composite reactor for catalytic hydrogenation;

[0015] (2) After the crude oil is fed into the composite reactor for catalytic hydrogenation, it is first subjected to hydrogenation pretreatment in a pipeline reactor to obtain a pretreated product;

[0016] (3) The pre-treated product flows out from the lower end of the pipeline reactor and enters the lower part of the shell. A small part of the heavy components in the material and the components of the liquid catalyst settle by gravity and are discharged from the ash discharge port. The majority of the remaining materials return upward, pass through the uniform distribution effect of the distribution plate, enter the solid catalyst bed for secondary hydrogenation treatment, and obtain secondary hydrogenation products, which are taken out from the discharge port.

[0017] During the secondary hydrogenation process, the pretreated product reacts in the solid catalyst bed, and the heat released by the reaction is conducted through the tube wall of the tubular reactor to the material in the tube, thereby increasing the temperature of the material in the tube and realizing the comprehensive utilization of waste heat.

[0018] Furthermore, in step (1), the liquid catalyst is a nickel-based room-temperature fluidity catalyst, the mass content of nickel metal element in the nickel-based room-temperature fluidity catalyst is 8 to 15%, preferably 13%, and the nickel-based room-temperature fluidity catalyst includes any one of a nickel-molybdenum fluidity catalyst, a nickel-cobalt fluidity catalyst, and a nickel-molybdenum-cobalt fluidity catalyst.

[0019] Preferably, the molar ratio of nickel to molybdenum in the nickel-molybdenum fluidity catalyst is 1:(0.1-0.5); the molar ratio of nickel to cobalt in the nickel-cobalt fluidity catalyst is 1:(0.2-0.6); the molar ratio of nickel to molybdenum to cobalt in the nickel-molybdenum-cobalt fluidity catalyst is 1:(0.03-0.1):(0.04-0.08).

[0020] Preferably, the fluid catalyst needs to be treated with 13X molecular sieve before use, and the treatment steps are: mixing the 13X molecular sieve with the fluid catalyst and treating at room temperature for 1 to 2 hours; the mass of the 13X molecular sieve is 5.5 to 5.8% of the total mass of the fluid catalyst, and the 13X molecular sieve is spherical with a particle size of 4 to 6 mm.

[0021] Furthermore, the dosage of the liquid catalyst is 200 to 2000 ppm.

[0022] Furthermore, in step (2), the treatment conditions of the hydrogenation pretreatment process are:

[0023] The temperature is 200-300°C;

[0024] The pressure is 2~10MPa;

[0025] The volume ratio of hydrogen to oil is 400 to 1000;

[0026] Airspeed 10~20h -1 .

[0027] Furthermore, in step (3), the solid catalyst is a molybdenum-nickel-based alumina catalyst, and the molybdenum-nickel-based alumina catalyst is any one of a molybdenum-nickel alumina catalyst and a cobalt-molybdenum-nickel alumina catalyst.

[0028] Preferably, the content of the molybdenum metal element in the molybdenum-nickel alumina catalyst is 5-15%, and the content of the nickel metal element is 10-18%.

[0029] Preferably, the content of cobalt metal element in the cobalt-molybdenum-nickel alumina catalyst is 5-10%, the content of molybdenum metal element is 3-8%, and the content of nickel metal element is 5-12%.

[0030] Furthermore, in step (3), the temperature of the secondary hydrotreatment process is 300-400°C.

[0031] Furthermore, the above-mentioned catalytic hydrogenation method for producing green renewable diesel with energy recovery also includes the following steps:

[0032] (1) After the secondary hydrogenation product is taken out from the discharge port of the catalytic hydrogenation composite reactor, it enters a hot high-pressure separator to separate hot high-fraction gas and hot high-fraction oil;

[0033] (2) The hot high-fraction oil enters the hot low-pressure separator to separate and remove the hydrogenation tailings, and then is heated in the fractionation heating furnace and enters the fractionation tower;

[0034] (3) The hot high-pressure gas enters the cold high-pressure separator, and the separated hydrogenated oil is heated in the fractionation heating furnace and then enters the fractionation tower;

[0035] (4) The material is fractionated into components in a distillation tower to ultimately obtain green renewable diesel.

[0036] Preferably, in step (1), the temperature of the hot high-pressure separator is 230-330° C., and the pressure is 1.9-9.5 MPa;

[0037] Preferably, in step (2), the temperature of the hot low-pressure separator is 200-300° C., and the pressure is 1-1.2 MPa;

[0038] Preferably, in step (3), the top pressure of the fractionation tower is 10-30 KPa, the feed temperature is 360-370°C, and the top temperature is 150-220°C.

[0039] Furthermore, the above-mentioned catalytic hydrogenation method for producing green renewable diesel by recovering energy also includes:

[0040] Heavy components such as high-ash oil and tailings discharged from the bottom of the composite reactor and hot low-pressure separator for catalytic hydrogenation are discharged after hydrogen separation in the ash discharge hot high-pressure separator and oil separation in the ash settling tank. The separated oil is combined with the unreacted oil discharged from the bottom of the distillation tower and returned to the initial end of the process as circulating oil, and then mixed into the raw oil for further hydrogenation treatment.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The catalytic hydrogenation method for producing green renewable diesel by recovering energy of the present invention provides a new process for preparing green renewable diesel by hydrogenation treatment.

[0043] 2. The catalytic hydrogenation method for producing green renewable diesel with energy recovery of the present invention proposes a new type of composite reactor. The composite hydrogenation reactor has the characteristic of large temperature difference between adjacent parts in the reactor, and realizes in-situ heat conduction of part of the chemical reaction heat. The heat exchange load of the heat exchanger arranged outside the reactor in the existing process is correspondingly reduced, and the heat loss that is difficult to avoid due to heat exchange outside the reactor is also reduced, while saving the corresponding equipment investment.

[0044] 3. The catalytic hydrogenation method for producing green renewable diesel by recovering energy of the present invention reduces the temperature of the raw materials entering the reactor by taking advantage of the high activity of the liquid catalyst at low temperature. In addition, the temperature-raising effect of heat transfer in the reactor can save 30% to 50% of the heat load of the heating furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flow chart of the catalytic hydrogenation method for producing green renewable diesel with energy recovery according to the present invention;

[0046] Figure 1 Among them, 1-raw material storage tank, 2-boosting pump, 3-reaction heating furnace, 4-homogeneous catalyst storage tank, 5-homogeneous catalyst filling pump, 6-composite reactor for catalytic hydrogenation, 7-hot high-pressure separator, 8-hot low-pressure separator, 9-cold high-pressure separator, 10-fractionation heating furnace, 11-fractionation tower, 12-circulating hydrogen compressor, 13-fresh hydrogen compressor, 14-ash discharge hot high-pressure separator, 15-ash settling tank.

[0047] Figure 2 and Figure 3 It is a schematic structural diagram of a composite reactor for catalytic hydrogenation of the present invention;

[0048] Figure 2 and Figure 3 In the figure, 16-single row spiral tube, 17-parallel straight tube bundle, 18-shell, 19-feed port, 20-discharge port, 21-ash discharge port, 22-solid catalyst bed, 23-distribution plate. DETAILED DESCRIPTION

[0049] The following non-limiting examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. The following content is only an exemplary description of the scope of the present invention, and those skilled in the art can make various changes and modifications to the invention of the present invention based on the disclosed content, and they should also fall within the scope of the present invention.

[0050] like Figure 2 , Figure 3As shown, a specific embodiment of the present invention provides a composite reactor for catalytic hydrogenation, including a shell 18 and a pipeline reactor arranged inside the shell 18; the pipeline reactor is a single row of spiral tubes 16 or is composed of parallel straight tube bundles 17; a solid catalyst bed 22 is arranged between the shell 18 and the pipeline reactor.

[0051] Specifically, the composite reactor for catalytic hydrogenation also includes: a feed port 19, a discharge port 20, an ash discharge port 21, and a distribution plate 23; the feed port 19 is arranged at the upper part of the shell 18 and is connected to the pipeline reactor; the discharge port 20 is arranged at the top of the shell 18; the ash discharge port 21 is arranged at the bottom of the shell 18; and the distribution plate 23 is arranged at the lower part of the solid catalyst bed in the shell 18.

[0052] The composite reactor for catalytic hydrogenation of the present invention buries a structure of a single row of spiral tubes or a parallel straight tube bundle (hereinafter referred to as a tubular structure) in a solid catalyst bed. The material in this reactor undergoes a homogeneous reaction at a lower temperature in the tubular structure and a multiphase reaction at a higher temperature on the fixed bed. Through the two-stage reaction process of the reactor with this structure, the chemical reaction heat generated by the material on the fixed bed will be conducted to the material in the tube through the tube wall of the tubular structure, so that the material in the tube is heated to the reaction activity temperature, thereby playing a role in rationally utilizing the chemical reaction heat.

[0053] like Figure 1 As shown, a specific embodiment of the present invention provides a catalytic hydrogenation method for producing green renewable diesel with energy recovery, comprising the following steps:

[0054] S1, the crude oil enters the catalytic hydrogenation composite reactor 6 for hydrogenation treatment:

[0055] (1) The crude oil in the raw material storage tank 1 is pressurized by the pressure pump 2 and then mixed with hydrogen, and then heated by the reaction heating furnace 3; the liquid catalyst in the homogeneous catalyst storage tank 4 is then pressurized and injected into the crude oil by the homogeneous catalyst filling pump 5, and then sent to the catalytic hydrogenation composite reactor 6;

[0056] (2) The crude oil is first subjected to hydrogenation pretreatment in the pipeline reactor 16 or 17 in the composite reactor 6 for catalytic hydrogenation to obtain a pretreated product;

[0057] (3) The pre-treated product flows out from the lower end of the pipeline reactor 16 or 17 and enters the lower part of the shell for sedimentation. A small part of the heavy components and liquid catalyst components are deposited here and discharged from the ash discharge port 21. The remaining main materials return upward, pass through the uniform distribution effect of the distribution plate 23, enter the solid catalyst bed 22 for secondary hydrogenation treatment, and obtain secondary hydrogenation products, which are collected from the discharge port 20.

[0058] During the secondary hydrogenation process, the pre-treated product reacts in the solid catalyst bed 22, and the heat released by the reaction is conducted to the material in the tube through the tube wall of the tubular reactor 16 or 17, so that the reaction heat is recovered and the waste heat is comprehensively utilized.

[0059] S2, after the secondary hydrogenation product is taken out from the discharge port 20 of the catalytic hydrogenation composite reactor 6, it enters the hot high-pressure separator 7 to separate the hot high-fraction gas and the hot high-fraction oil;

[0060] S3, the hot high-fraction oil enters the hot low-pressure separator 8, separates and removes the hydrogenation tailings, and then is heated by the fractionation heating furnace 10 and enters the fractionation tower 11;

[0061] S4, the hot high-fraction gas enters the cold high-pressure separator 9, the separated hydrogenated oil is heated in the fractionation heating furnace 10, and then enters the fractionation tower 11;

[0062] S5. The material is fractionated in the fractionation tower 11 to finally obtain green renewable diesel.

[0063] The heavy components such as high-ash oil and tailings discharged from the bottom of the catalytic hydrogenation composite reactor 6 and the hot low-pressure separator 8 are discharged after oil separation in the ash settling tank 15. The separated oil is combined with the unreacted oil discharged from the bottom of the distillation tower 11 and returned to the initial end of the process as circulating oil, and then mixed into the raw oil for further hydrogenation treatment.

[0064] In the present application, the liquid catalyst is prepared according to the existing process, as long as the composition content of the liquid catalyst is met, there is no special limitation. For example, the liquid catalyst can be prepared by grinding and mixing the corresponding metal salt, and then adding an organic acid. The corresponding nickel metal salt can be selected from any one of nickel carbonate, nickel acetate, nickel sulfate and nickel nitrate, and the molybdenum metal salt can be selected from any one of ammonium heptamolybdate, ammonium tetramolybdate and sodium heptamolybdate, and the cobalt metal salt can be selected from any one of cobalt acetate, cobalt carbonate and cobalt nitrate. The specific preparation method of the above-mentioned liquid catalyst and the specific type of metal salt do not constitute a limitation to the present application. In the specific embodiment part of the present application, the liquid catalyst is prepared by grinding and mixing the corresponding metal salt, and then adding an organic acid, and the corresponding nickel metal salt is selected from nickel nitrate, the cobalt metal salt is selected from cobalt nitrate, and the molybdenum metal salt is selected from ammonium heptamolybdate.

[0065] The present invention is further described below by way of specific examples. Unless otherwise specified, the various chemical reagents used in the examples of the present invention are obtained through conventional commercial channels.

[0066] Example 1

[0067] A catalytic hydrogenation method for producing green renewable diesel with energy recovery comprises the following steps:

[0068] S1. The raw oil (gutter oil) enters the catalytic hydrogenation composite reactor for hydrogenation treatment:

[0069] (1) The crude oil is pressurized by a pressure pump and then mixed with hydrogen, and then heated by a heating furnace. The liquid catalyst is pressurized and injected into the crude oil at a concentration of 200 ppm, and then sent to a composite reactor for catalytic hydrogenation;

[0070] The liquid catalyst is a nickel-molybdenum fluid catalyst, wherein the molar ratio of nickel to molybdenum is 1:0.5, and the mass content of nickel is 13%.

[0071] (2) The crude oil is first subjected to hydrogenation pretreatment in a pipeline reactor 16 to obtain a pretreated product; the hydrogenation pretreatment conditions are: temperature 300° C., hydrogen pressure 2 MPa, hydrogen-to-oil volume ratio 400, and space velocity 20 h -1 .

[0072] (3) The pre-treated product flows out from the lower end of the pipeline reactor and enters the lower part of the shell for sedimentation. A small amount of heavy components and liquid catalyst components are deposited here and discharged from the ash discharge port. The remaining main materials return upward, pass through the uniform distribution effect of the distribution plate, enter the solid catalyst bed, and undergo secondary hydrogenation treatment at 400°C to obtain secondary hydrogenation products, which are collected from the discharge port.

[0073] The solid catalyst is a molybdenum-nickel alumina catalyst, in which the content of the molybdenum metal element is 5% and the content of the nickel metal element is 18%.

[0074] S2, after the secondary hydrogenation product is taken out from the discharge port of the catalytic hydrogenation composite reactor, it enters the hot high-pressure separator to separate hot high-fraction gas and hot high-fraction oil at a temperature of 330°C and a pressure of 9.5MPa;

[0075] S3, the hot high-fraction oil enters the hot low-pressure separator, where it is separated and the hydrogenation tailings are removed at a temperature of 300°C and a pressure of 1.2MPa, and then heated by the fractionation heating furnace and enters the fractionation tower. The top pressure of the fractionation tower is 30KPa, the feed temperature is 370°C, and the top temperature is 220°C;

[0076] S4, the hot high-fraction gas enters the cold high-pressure separator, and the hydrogenated oil separated at 70°C and 1MPa is heated in the fractionation heating furnace and then enters the fractionation tower;

[0077] S5, the material is fractionated in a fractionation tower to obtain green renewable diesel;

[0078] S6. Heavy components such as high-ash oil and tailings discharged from the bottom of the composite reactor for catalytic hydrogenation and the hot low-pressure separator are discharged after hydrogen separation in the ash discharge hot high-pressure separator and oil separation in the ash settling tank. The separated oil is combined with the unreacted oil discharged from the bottom of the distillation tower and returned to the initial end of the process as circulating oil, and then mixed into the raw oil for further hydrogenation treatment.

[0079] Example 2

[0080] A green renewable diesel catalytic hydrogenation method for recovering energy comprises the following steps:

[0081] S1. The raw oil (coconut oil) enters the catalytic hydrogenation composite reactor for hydrogenation treatment:

[0082] (1) The crude oil is pressurized by a pressure pump and then mixed with hydrogen. The crude oil is heated in a heating furnace, and a liquid catalyst is pressurized and injected into the crude oil at a concentration of 1000 ppm, and then sent to a composite reactor for catalytic hydrogenation;

[0083] The liquid catalyst is a nickel-cobalt fluid catalyst, in which the molar ratio of nickel to cobalt is 1:0.6, and the mass content of nickel is 13%.

[0084] (2) The crude oil is first subjected to hydrogenation pretreatment in a pipeline reactor 17 to obtain a pretreated product; the temperature is 200° C., the hydrogen pressure is 10 MPa, the hydrogen-to-oil volume ratio is 1000, and the space velocity is 10 h -1 .

[0085] (3) The pre-treated product flows out from the lower end of the pipeline reactor and enters the bottom of the shell for sedimentation. A small amount of heavy components and liquid catalyst components are deposited here and discharged from the ash discharge port. The remaining main materials return upward, pass through the uniform distribution effect of the distribution plate, enter the solid catalyst bed for secondary hydrogenation treatment, and obtain secondary hydrogenation products, which are taken out from the discharge port; the secondary hydrogenation treatment conditions are: temperature 200 °C.

[0086] The solid catalyst is a cobalt-molybdenum-nickel alumina catalyst, the content of molybdenum metal element is 3%, the content of cobalt metal element is 10%, and the content of nickel metal element is 12%.

[0087] S2, after the secondary hydrogenation product is taken out from the discharge port of the catalytic hydrogenation composite reactor, it enters the hot high-pressure separator to separate hot high-fraction gas and hot high-fraction oil at a temperature of 230°C and a pressure of 1.9MPa;

[0088] S3, the hot high-fraction oil enters the hot low-pressure separator, where it is separated and the hydrogenation tailings are removed at a temperature of 200°C and a pressure of 1MPa, and then heated by the fractionation heating furnace and enters the fractionation tower. The top pressure of the fractionation tower is 10KPa, the feed temperature is 360°C, and the top temperature is 150°C;

[0089] S4, the hot high-fraction gas enters the cold high-pressure separator, and the hydrogenated oil separated at 50°C and 6MPa is heated in the fractionation heating furnace and then enters the fractionation tower;

[0090] S5, the material is fractionated in a fractionation tower to obtain green renewable diesel;

[0091] S6. Heavy components such as high-ash oil and tailings discharged from the bottom of the composite reactor and hot low-pressure separator for catalytic hydrogenation are discharged after hydrogen separation and oil separation in the ash-discharging hot high-pressure separator. The separated oil is combined with the unreacted oil discharged from the bottom of the distillation tower and returned to the initial end of the process as circulating oil, and then mixed into the raw oil for further hydrogenation treatment.

[0092] Example 3

[0093] A green renewable diesel catalytic hydrogenation method for recovering energy comprises the following steps:

[0094] S1. Raw oil (gutter oil) enters the composite reactor for hydrogenation treatment:

[0095] (1) The crude oil is pressurized by a pressure pump and then mixed with hydrogen. The crude oil is heated in a heating furnace, and the liquid catalyst is pressurized and injected into the crude oil at a concentration of 2000 ppm, and then sent to a composite reactor;

[0096] The liquid catalyst is a nickel-molybdenum-cobalt fluid catalyst, wherein the molar ratio of nickel:molybdenum:cobalt is 1:0.03:0.08, and the mass content of nickel is 13%.

[0097] (2) The crude oil is first subjected to hydrogenation pretreatment in a pipeline reactor 17 to obtain a pretreated product; the temperature is 200° C., the hydrogen pressure is 10 MPa, the hydrogen-to-oil volume ratio is 1000, and the space velocity is 10 h -1 .

[0098] (3) The pre-treated product flows out from the lower end of the pipeline reactor and enters the bottom of the shell for sedimentation. A small amount of heavy components and liquid catalyst components are deposited here and discharged from the ash discharge port. The remaining main materials return upward, pass through the uniform distribution effect of the distribution plate, enter the solid catalyst bed for secondary hydrogenation treatment, and obtain secondary hydrogenation products, which are taken out from the discharge port; the secondary hydrogenation treatment conditions are: temperature 200 ° C, volume space velocity 5h -1 .

[0099] The solid catalyst is a molybdenum-nickel alumina catalyst, in which the content of the molybdenum metal element is 15% and the content of the nickel metal element is 10%.

[0100] S2, after the secondary hydrogenation product is taken out from the discharge port of the catalytic hydrogenation composite reactor, it enters the hot high-pressure separator to separate hot high-fraction gas and hot high-fraction oil at a temperature of 330°C and a pressure of 9.5MPa;

[0101] S3, the hot high-fraction oil enters the hot low-pressure separator, where it is separated and the hydrogenation tailings are removed at a temperature of 300°C and a pressure of 1.2MPa, and then heated by the fractionation heating furnace and enters the fractionation tower. The top pressure of the fractionation tower is 30KPa, the feed temperature is 370°C, and the top temperature is 220°C;

[0102] S4, the hot high-fraction gas enters the cold high-pressure separator, and the hydrogenated oil separated at 70°C and 1MPa is heated in the fractionation heating furnace and then enters the fractionation tower;

[0103] S5, the material is fractionated in a fractionation tower to obtain green renewable diesel;

[0104] S6. Heavy components such as high-ash oil and tailings discharged from the bottom of the composite reactor and hot low-pressure separator for catalytic hydrogenation are discharged after hydrogen separation and oil separation in the ash-discharging hot high-pressure separator. The separated oil is combined with the unreacted oil discharged from the bottom of the distillation tower and returned to the initial end of the process as circulating oil, and then mixed into the raw oil for further hydrogenation treatment.

[0105] The properties of the feedstock oil in Examples 1, 2 and 3 are shown in Table 1 below:

[0106] Table 1. Raw oil properties

[0107] project Waste oil Coconut Oil <![CDATA[Density (20 °C) (g / cm 3 )]]> 0.83 0.90 <![CDATA[Kinematic viscosity (50 °C) (mm 2 / s)]]> 32.90 58.31 S content (μg / g) 153.0 2.1 N content (μg / g) 219.0 2.0 O content (μg / g) 9.8 13.9 Acid value (mgKOH / g) 168.0 0.9

[0108] Example 4

[0109] The difference from Example 1 is that the composition of the nickel-molybdenum fluid catalyst during the hydrogenation pretreatment is different. The molar ratio of nickel to molybdenum in the nickel-molybdenum fluid catalyst in this example is 1:0.1.

[0110] Example 5

[0111] The difference from Example 2 is that the composition of the nickel-cobalt fluid catalyst during the hydrogenation pretreatment is different. The molar ratio of nickel to cobalt in the nickel-cobalt fluid catalyst in this embodiment is 1:0.2; the solid catalyst in the secondary hydrogenation treatment is a cobalt-molybdenum-nickel alumina catalyst, and the content of molybdenum metal element is 8%, the content of cobalt metal element is 5%, and the content of nickel metal element is 5%.

[0112] Example 6

[0113] The difference from Example 3 is that the composition of the nickel-molybdenum-cobalt fluidity catalyst during the hydrogenation pretreatment is different. The molar ratio of nickel, molybdenum and cobalt in the nickel-molybdenum-cobalt fluidity catalyst in this example is 1:0.1:0.04.

[0114] Example 7

[0115] The difference from Example 1 is that, before using the nickel-molybdenum fluid catalyst during hydrogenation pretreatment, 13X molecular sieve is first added to the catalyst and treated at room temperature for 2 hours. The mass of the 13X molecular sieve is 5.5% of the total mass of the fluid catalyst. The 13X molecular sieve is spherical with a particle size of 4 mm.

[0116] Example 8

[0117] The difference from Example 1 is that, in the hydrogenation pretreatment process, 13X molecular sieve is added to the nickel-molybdenum fluid catalyst before use, and the catalyst is treated at room temperature for 1 hour. The mass of 13X molecular sieve is 5.8% of the total mass of the fluid catalyst. The 13X molecular sieve is spherical with a particle size of 6 mm.

[0118] Example 9

[0119] The difference from Example 7 is that during the treatment of the nickel-molybdenum fluid catalyst with the 13X molecular sieve, the mass of the 13X molecular sieve is 5.1% of the total mass of the fluid catalyst.

[0120] Example 10

[0121] The difference from Example 7 is that during the treatment of the nickel-molybdenum fluid catalyst with the 13X molecular sieve, the mass of the 13X molecular sieve is 6.2% of the total mass of the fluid catalyst.

[0122] Comparative Example 1

[0123] The difference from Example 1 is that the composite reactor in this comparative example is replaced by a two-step hydrogenation process in which a pipeline reactor and a fixed bed reactor are connected in series, that is, the hydrogenation treatment steps are:

[0124] (1) The crude oil (waste oil) is pressurized by a pressure pump and mixed with hydrogen, and then heated in a heating furnace. A liquid catalyst (same as in Example 1) is pressurized and injected into the crude oil at 200 ppm, and then fed into a pipeline reactor;

[0125] (2) The feedstock oil is subjected to hydrogenation pretreatment in a pipeline reactor (the pipeline reactor 16 is used as an example in this comparative example) to obtain a pretreated product; the hydrogenation pretreatment conditions remain unchanged;

[0126] (3) The pretreatment product flows out from the top of the pipeline reactor and enters the fixed bed reactor for secondary hydrogenation treatment to obtain a secondary hydrogenation product; the secondary hydrogenation treatment conditions remain unchanged.

[0127] Comparative Example 2

[0128] The difference from Example 1 is that the composite reactor in this comparative example is replaced by a two-step hydrogenation method in which a suspended bed hydrocracking reactor and a fixed bed reactor are connected in series; that is, the steps of the green renewable diesel catalytic hydrogenation method for recovering energy are as follows:

[0129] S1. The raw oil (waste oil) is pressurized by a booster pump and mixed with hydrogen, then heated by a heating furnace and enters a suspended bed hydrocracking reactor for hydrogenation reaction; the reaction conditions are: temperature 300°C, hydrogen pressure 2MPa, hydrogen-oil volume ratio 400, space velocity 20h -1 .

[0130] The catalyst added to the suspended bed hydrocracking reactor is a nickel-molybdenum fluid catalyst, which is the same as that in Example 1.

[0131] S2. The reaction product flowing out from the top of the suspended bed hydrocracking reactor enters the fixed bed reactor for secondary hydrogenation treatment to obtain a secondary hydrogenation product; the secondary hydrogenation treatment conditions remain unchanged.

[0132] The catalyst added to the fixed bed reactor is a molybdenum-nickel alumina catalyst, which is the same as that in Example 1.

[0133] S3, the secondary hydrogenation product flows out of the fixed bed reactor and enters the hot high-pressure separator to separate hot high-fraction gas and hot high-fraction oil;

[0134] S4, the hot high-fraction oil enters the hot low-pressure separator to separate and remove the hydrogenation tailings, and then is heated by the fractionation heating furnace and enters the fractionation tower;

[0135] S5, the hot high-fraction gas enters the cold high-pressure separator, the separated hydrogenated oil is heated in the fractionation heating furnace, and then enters the fractionation tower;

[0136] S6. The material is fractionated into components in a fractionation tower to obtain green renewable diesel.

[0137] Comparative Example 3

[0138] The difference from Comparative Example 1 is that the composite reactor in this comparative example is replaced by a suspended bed hydrocracking reactor, that is, the steps of the green renewable diesel catalytic hydrogenation method for recovering energy are as follows:

[0139] S1. The raw oil (waste oil) is pressurized by a booster pump and mixed with hydrogen, then heated by a heating furnace and enters a suspended bed hydrocracking reactor for hydrogenation reaction; the reaction conditions are: temperature 300°C, hydrogen pressure 2MPa, hydrogen-oil volume ratio 400, space velocity 20h -1 .

[0140] The catalyst added to the suspended bed hydrocracking reactor is a nickel-molybdenum fluid catalyst, which is the same as that in Example 1.

[0141] S2, the reaction product flowing out of the top of the suspended bed hydrocracking reactor enters the hot high-pressure separator to separate hot high-fraction gas and hot high-fraction oil;

[0142] S3, the hot high-fraction oil enters the hot low-pressure separator to separate and remove the hydrogenation tailings, and then is heated by the fractionation heating furnace and enters the fractionation tower;

[0143] S4, the hot high-fraction gas enters the cold high-pressure separator, the separated hydrogenated oil is heated in the fractionation heating furnace, and then enters the fractionation tower;

[0144] S5. The material is fractionated into components in a fractionation tower to obtain green renewable diesel.

[0145] Comparative Example 4

[0146] The difference from Comparative Example 1 is that there is no fixed catalyst bed in the composite reactor for catalytic hydrogenation in this comparative example, that is, the steps of the green renewable diesel catalytic hydrogenation method for recovering energy are as follows:

[0147] S1. The raw oil (waste oil) is pressurized by a pressure pump and mixed with hydrogen, and then heated by a heating furnace. The liquid catalyst is pressurized and injected into the raw oil at a concentration of 200ppm, and enters the pipeline reactor for hydrogenation reaction; the reaction conditions are: temperature 300℃, hydrogen pressure 2MPa, hydrogen-oil volume ratio 400, space velocity 20h -1 .

[0148] S2, the reaction product flowing out of the top of the pipeline reactor enters the hot high-pressure separator to separate hot high-fraction gas and hot high-fraction oil;

[0149] S3, the hot high-fraction oil enters the hot low-pressure separator to separate and remove the hydrogenation tailings, and then is heated by the fractionation heating furnace and enters the fractionation tower;

[0150] S4, the hot high-fraction gas enters the cold high-pressure separator, the separated hydrogenated oil is heated in the fractionation heating furnace, and then enters the fractionation tower;

[0151] S5. The material is fractionated into components in a fractionation tower to obtain green renewable diesel.

[0152] Comparative Example 5

[0153] The difference from Comparative Example 1 is that the composite reactor for catalytic hydrogenation in this comparative example is replaced by a fixed bed reactor, that is, the steps of the green renewable diesel catalytic hydrogenation method for recovering energy are as follows:

[0154] S1, the raw oil (waste oil) is pressurized by a pressure pump and mixed with hydrogen, then heated by a heating furnace and enters a fixed bed reactor for hydrogenation reaction;

[0155] The catalyst added to the fixed bed reactor is a nickel-molybdenum fluid catalyst, which is the same as that in Example 1.

[0156] S2, the reaction products flowing out of the fixed bed reactor enter the hot high-pressure separator to separate hot high-fraction gas and hot high-fraction oil;

[0157] S3, the hot high-fraction oil enters the hot low-pressure separator to separate and remove the hydrogenation tailings, and then is heated by the fractionation heating furnace and enters the fractionation tower;

[0158] S4, the hot high-fraction gas enters the cold high-pressure separator, the separated hydrogenated oil is heated in the fractionation heating furnace, and then enters the fractionation tower;

[0159] S5. The material is fractionated into components in a fractionation tower to obtain green renewable diesel.

[0160] Test Example 1

[0161] The hydroprocessing products obtained in the above examples and comparative examples and the final product diesel were tested, and the results are shown in Table 2 below.

[0162] Table 2. Hydrotreating results and diesel quality

[0163]

[0164] The results show that compared with the process provided in the comparative example, the green renewable diesel catalytic hydrogenation method for recovering energy provided by the present invention has a raw material conversion rate of more than 99% in the hydrogenation process, and the raw material conversion rate is high; the diesel produced has a low sulfur content, a high cetane number, a low acid value, a high alkane content, and a high diesel product quality.

[0165] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A composite reactor for catalytic hydrogenation, characterized in that: It comprises a shell 18 and a pipeline reactor arranged inside the shell 18; a solid catalyst bed 22 is arranged between the shell 18 and the pipeline reactor; wherein the pipeline reactor is composed of a single row of spiral tubes 16 or a parallel straight tube bundle 17.

2. The composite reactor for catalytic hydrogenation according to claim 1, characterized in that: Also includes: Feed port 19, discharge port 20, ash discharge port 21, distribution plate 23; The feed port 19 is disposed at the upper portion of the shell 18 and communicated with the pipeline reactor; the discharge port 20 is disposed at the top of the shell 18; the ash discharge port 21 is disposed at the bottom of the shell 18; and the distribution plate 23 is disposed at the lower portion of the solid catalyst bed 22.

3. A catalytic hydrogenation method for producing green renewable diesel with energy recovery, characterized in that: The method comprises utilizing the composite reactor for catalytic hydrogenation as claimed in claim 1 or 2 to hydrogenate crude oil.

4. The catalytic hydrogenation method for producing green renewable diesel with energy recovery according to claim 3, characterized in that: The raw material oil is selected from any one of waste oil, vegetable oil and animal oil.

5. The catalytic hydrogenation method for producing green renewable diesel with energy recovery according to claim 3, characterized in that: The steps of the hydrotreating are: (1) The crude oil in the raw material storage tank 1 is pressurized by the pressure pump 2 and then mixed with hydrogen, and then heated by the reaction heating furnace 3; the liquid catalyst in the homogeneous catalyst storage tank 4 is pressurized and injected into the crude oil by the homogeneous catalyst filling pump 5, and then sent to the catalytic hydrogenation composite reactor 6; (2) After the crude oil is fed into the composite reactor 6 for catalytic hydrogenation, it is first subjected to hydrogenation pretreatment in a pipeline reactor 16 or 17 to obtain a pretreated product; (3) The pre-treated product flows out from the lower end of the pipeline reactor 16 or 17 and enters the bottom of the shell for sedimentation. The heavy components and liquid catalyst fine particles are deposited here and discharged from the ash discharge port 21. The remaining materials are turned back upward, distributed evenly by the distribution plate 23, and enter the solid catalyst bed 22 for secondary hydrogenation treatment to obtain secondary hydrogenation products, which are collected from the discharge port 20.

6. The catalytic hydrogenation method for producing green renewable diesel with energy recovery according to claim 5, characterized in that: During the secondary hydrogenation process, the pretreated product reacts in the solid catalyst bed 22, and the heat released by the reaction is transferred to the material in the tube through the tube wall of the tubular reactor 16 or 17, so that the temperature of the material in the tube is increased, thereby realizing comprehensive utilization of waste heat.

7. The catalytic hydrogenation method for producing green renewable diesel with energy recovery according to claim 5, characterized in that: In step (1), the liquid catalyst is a nickel-based catalyst that is fluid at room temperature.

8. The catalytic hydrogenation method for producing green renewable diesel with energy recovery according to claim 7, characterized in that: The liquid catalyst needs to be treated with 13X molecular sieve before use, and the mass of the 13X molecular sieve is 5.5-5.8% of the liquid catalyst; the 13X molecular sieve is spherical, and the particle size is 4-6 mm.

9. The catalytic hydrogenation method for producing green renewable diesel with energy recovery according to claim 5, characterized in that: The catalytic hydrogenation method for producing green renewable diesel with energy recovery also includes the following steps: (1) After the secondary hydrogenation product is taken out from the discharge port 20 of the catalytic hydrogenation composite reactor 6, it enters the hot high-pressure separator 7 to separate the hot high-fraction gas and the hot high-fraction oil; (2) The hot high-fraction oil enters the hot low-pressure separator 8 to separate and remove the hydrogenation tailings, and then is heated by the fractionation heating furnace 10 and enters the fractionation tower 11; (3) The hot high-fraction gas enters the cold high-pressure separator 9, and the separated hydrogenated oil is heated in the fractionation heating furnace 10 and then enters the fractionation tower 11; (4) The material is fractionated into components in a fractionation tower 11, and green renewable diesel is finally obtained.

10. The catalytic hydrogenation method for producing green renewable diesel with energy recovery according to claim 9, characterized in that: The energy-harvesting catalytic hydrogenation method for producing green renewable diesel also includes the following steps: The heavy components such as high-ash oil and tailings discharged from the bottom of the catalytic hydrogenation composite reactor 6 and the hot low-pressure separator 8 are discharged after oil separation in the ash settling tank 15. The separated oil is combined with the unreacted oil discharged from the bottom of the distillation tower 11 and returned to the initial end of the process as circulating oil, and then mixed into the raw oil for further hydrogenation treatment.

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