WO2023236390A1 - Method and system for producing alkylated biomass aviation fuel from waste oils and fats - Google Patents

Abstract

Disclosed in the present invention are a method and system for producing an alkylated biomass aviation fuel from waste oils and fats. The method comprises: taking raw oil and mixed hydrogen as main raw materials, successively subjecting same to a hydrofining reaction, stripping separation and an isomerization reaction, which are continuously performed, and subjecting the product obtained from the isomerization reaction to cooling, gas-liquid separation and fractionation to obtain aviation fuel, wherein the oil phase material obtained from the hydrofining reaction and raw materials for the hydrofining reaction are subjected to heat exchange and then directly to the stripping separation; during the operation of the stripping separation, a high-pressure hydrogen gas is used as a stripping working medium, and the hydrogen-sulfide-containing hydrogen gas recovered by the stripping separation is used as recycle hydrogen and is combined with supplementary hydrogen to serve as mixed hydrogen for use; and the oil phase material obtained from the stripping separation and a product material for the isomerization reaction are subjected to heat exchange and then directly to the isomerization reaction. In the present invention, by means of an efficient stripping separator, hydrogen sulfide and water vapor are completely removed; and generated oil at the bottom of the efficient separator enters an isomerization reaction system by means of self-pressure, such that the energy consumption in the process and production procedures are effectively reduced.

Description

A method and system for producing alkylated biomass aviation fuel from waste oil Technical field

The invention relates to the field of biomass energy, and specifically relates to a method and system for producing alkylated biomass aviation fuel from waste oil.

Background technique

At present, my country's national consumption level is gradually improving, and the amount of animal and plant waste oils and fats produced by the increasingly prosperous catering industry is increasing year by year. For the sake of people's dietary safety, the state has further increased control efforts to prevent waste oils and fats from returning to the dining table. As a zero-carbon energy source, biomass energy will play an important role, and its energy industry will also usher in a period of major development opportunities, and the rational utilization of waste animal and vegetable oils is of great significance.

The patent document with document number CN 111909720 A discloses a method for hydrogenating waste animal and vegetable oils. The steps include: a) mixing the waste animal and vegetable oils with the product oil obtained in step c) to obtain a mixture; b) the mixture and hydrogen Mix and carry out hydrogenation reaction; c) separate the gas and product oil through hot and high-pressure separation; d) part of the product oil obtained in step c) is returned to step a) and mixed with waste animal and vegetable oil raw materials, and the remaining product oil and gas are separated by cold and high pressure. ; e) The product oil and water obtained by cold high-pressure separation are separated at low pressure, and the product oil is stripped and desulfurized, and the water is discharged; f) After desulfurization, the product oil is subjected to atmospheric fractionation to obtain renewable light hydrocarbons and renewable alkane finished products. This document does not deal with isomerization reactions. At the same time, after the hydrogenation reaction is completed in this reaction, the stripping operation is performed after hot high-pressure separation, cold high-pressure separation, and low-pressure separation. The heat generated by the hydrogenation reaction is not fully utilized.

The conventional technical route for using oils and fats to prepare aviation dyes is: "waste animal and vegetable oils → hydrorefining → high and low pressure separation → stripping → isomerization → high and low pressure separation → fractionation". Disadvantages: The existing waste grease hydrogenation device produces biomass aviation fuel. The hydrorefining catalyst is an acidic active catalyst, and the refining reaction system must add 300-700ppm dimethyl disulfide (C ₂ H ₆ S ₂ ), this substance produces H ₂ when it encounters hydrogen. S circulates with the circulating hydrogen in the entire reaction system, and part of it is reacted to generate oil first to reach a high temperature. The high temperature operating conditions are 40 to 50°C, 4.0 to 5.5 MPa, and then Reduce the pressure to cold low fraction to remove excess light hydrocarbons and a small amount of hydrogen sulfide. The low fraction operating conditions are 40-50℃, 1.0-1.8MPa. Finally, after heat exchange to the stripping tower for stripping and desulfurization, the operating conditions are 180 ~200℃, 0.5~1.5MPa, to reach the second stage hydroisomerization device. During this period, the temperature changes a lot, and the materials undergo a lot of phase changes. It requires moving equipment to boost the pressure to the isomerization reaction pressure before entering the isomerization device. The operating conditions are 280~360℃, the pressure is 2.5~3.5MPa, and it consumes a lot of electricity. Oil containing hydrogen sulfide will corrode equipment and pipelines to a certain extent. In order to reduce the risk of corrosion, the investment cost of equipment and pipes needs to be increased.

Contents of the invention

In order to solve the problems in the prior art, the present invention provides a method for producing alkylated biomass aviation fuel from waste grease. By using a high-efficiency stripping separator to directly strip the products generated by the refining reaction and separate the gas and liquid phases, hydrogen sulfide and water vapor are completely removed. The generated oil at the bottom of the high-efficiency separator enters the isomerization reaction system under pressure, effectively effectively Reduce process energy consumption and production processes.

A method for producing alkylated biomass aviation fuel from waste oil, using feed oil and mixed hydrogen as the main raw materials, including sequential and continuous hydrofining reactions, stripping separation and isomerization reactions. The isomerization reaction yields The product is cooled, gas-liquid separated and fractionated to obtain the aviation fuel;

The oil phase material obtained by the hydrorefining reaction is directly subjected to the stripping separation after heat exchange with the raw material of the hydrorefining reaction;

The stripping and separation operation uses high-pressure hydrogen as the stripping working fluid, and the hydrogen containing hydrogen sulfide recovered by stripping and separating is used as circulating hydrogen and is combined with supplementary hydrogenation to be used as the mixed hydrogen; the oil phase material obtained by stripping and separated is mixed with the foreign matter. The product materials of the isomerization reaction are directly subjected to the isomerization reaction after heat exchange.

Through the hydrorefining reaction, metals and/or O and/or S and/or N, etc. in the raw oil can be removed; through the stripping separation operation, the metal-containing and/or O and/or N in the oil phase can be removed. /or S and/or N products and short-chain hydrocarbons with low boiling points, etc. The hydrofinishing reaction and the isomerization reaction are both carried out in the presence of a catalyst, and at the same time, the consumed hydrogen is added in the hydrofining reaction and the isomerization reaction.

As a preferred method, a method for producing alkylated biomass aviation fuel from waste grease includes:

1) Add dimethyl disulfide to the inlet of the raw oil feed pump, and the raw oil is boosted by the hydrogenation feed pump and mixed with circulating hydrogen as the reaction feed. The mixed reaction feed enters the hydrorefining reactor for hydrodeoxygenation, desulfurization, denitrification, and demetallization reactions to generate alkylated hydrocarbons, hydrogen sulfide, carbon monoxide, carbon dioxide and other reaction products;

2) Perform high-pressure stripping on the oil produced by the reaction to remove short-chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide, ammonia and other substances;

3) The cooled circulating hydrogen (40~45℃, 5.0MPa) removes the sulfur-containing sewage in the cold high-pressure separator, and the remaining small amount of circulating hydrogen containing hydrogen sulfide continues to be recycled to reduce dimethyl disulfide amount of injection.

4) The circulating hydrogen is mixed with the raw oil again through the pressurization cycle of the circulating hydrogen compressor and enters the reaction system for recycling. The hydrogen lost in the reaction system is replenished by the new hydrogen compressor;

5) The bottom outlet pipeline of the high-efficiency stripping separator is mixed with the isomeric circulating hydrogen;

6) Enter the isomerization reactor to selectively crack long-chain hydrocarbon molecules;

7) After air cooling, the isomeric products enter the isomeric cold high-fraction liquid separation, and the liquid phase directly enters the subsequent process for fractionation.

Preferably, the hydrorefining reaction conditions are: pressure is 3.5-6MPa, temperature is 240-360°C, space velocity is 0.4-2.0h ^-1 , and hydrogen-oil ratio is 1000-1400:1 (V/V).

Preferably, the operating conditions of stripping separation are: stripping temperature is 200-280°C, and pressure is 4-5.5MPa. The gas operation directly uses high-pressure hydrogen. On the one hand, it can achieve high-temperature stripping, which can more thoroughly remove impurities in the product oil; it also facilitates the recycling of hydrogen.

Preferably, the reaction conditions of the isomerization reaction are: pressure is 1.5-3.5MPa, temperature is 240-370°C, space velocity is 0.2-0.8h ^-1 , and hydrogen-oil ratio is 500-700:1 (V/V) . As a further preference, the operating conditions are: temperature 260-360°C, pressure 2.5-3.5MPa.

Preferably, the dimethyl disulfide, feed oil and mixed hydrogen are mixed first, and then the hydrorefining reaction is performed. The present invention uses low-pressure sulfur injection to maintain high activity of the hydrorefining catalyst during the deoxygenation reaction.

The hydrorefining reaction includes one or more of deoxygenation reaction, desulfurization reaction, denitrification reaction and demetallization reaction using hydrogen.

Preferably, the temperature of the raw material for the hydrorefining reaction and the oil phase material obtained by the hydrorefining reaction is increased to 190-210°C after heat exchange, and then heated to 280-340°C.

Preferably, after heat exchange between the oil phase material obtained by the hydrorefining reaction and the raw material of the hydrorefining reaction, the temperature drops to 240-280°C and the pressure is 4.5-5.5MPa.

Preferably, the amount of hydrogen used in stripping separation is 5.5 to 6.5 MPa; the added amount is 3 to 10% of the feed amount.

Preferably, the gas phase separated by stripping is cooled to 40-50°C by a high-pressure air cooler, and then enters a cold high-pressure separator. A part of the hydrogen-containing hydrogen separated by the cold high-pressure separator is pressurized and used as the circulating hydrogen. The short-chain hydrocarbons separated by the cold high-pressure separator and the cooling material obtained by the isomerization reaction are combined into the gas-liquid separation. A part of the water phase obtained by the cold high-pressure separator is combined with newly injected water and returned to the high-pressure air cooler for desalination. .

Preferably, the content of hydrogen sulfide in the circulating hydrogen is 200 to 700 ppm. During the hydrorefining reaction process, the amount of dimethyl disulfide added can be controlled according to the hydrogen sulfide content in the system.

Preferably, the oil phase obtained by stripping and separation is mixed with isomeric circulating hydrogen and supplementary hydrogenation, and then reacts with isomerization to form biological heat exchange to 260-350°C; and then heats it to 300-360°C through heating equipment; isomerization The product obtained by the reaction is first exchanged with the oil phase separated by stripping, and then cooled to 40-45°C by high-pressure air cooling, and then gas-liquid separation is performed, and part of the obtained hydrogen is reused as isomerized circulating hydrogen.

Preferably, in the hydrorefining reaction, a three-layer supported catalyst is used in order from the raw material inlet, which is a low-activity demetallization catalyst with simultaneous desulfurization and deoxygenation functions, an active demetallization catalyst, and a high-activity demetallization catalyst. The main agent of each catalyst is Co-Mo-Ni;

In the isomerization reaction, two layers of supported catalysts are used in sequence from the raw material inlet, which are active oxidation state metal desulfurization catalysts and high activity condensation reducing isomerization catalysts. The main agent of the active oxidation state metal desulfurization catalyst is CaO\ZnO. , the main agent of the high activity pour point isomerization catalyst is Pt/Pd.

Preferably, the catalyst compositions are as follows:

Low activity demetallization catalyst: carrier: Y-Al ₂ O ₃ , 3 to 5%; auxiliary: supported molecular sieve 75 to 85%; main agent: Co-Mo-Ni metal component, 10 to 20%;

Highly active demetallization catalyst: carrier: Y-Al ₂ O ₃ , 5 to 8%; additive: supported molecular sieve 60 to 70%; main agent: Co-Mo-Ni metal component, 25 to 35%;

Highly active demetallization catalyst: carrier: mixture of alkaline metal oxide and Y-Al ₂ O ₃ , 10 to 20%; auxiliary: active molecular sieve 45 to 55%; main agent: Co-Mo metal component, 35 to 45 %;

Active oxidation state metal desulfurization catalyst: carrier: Y-Al ₂ O ₃ , 15-25%; auxiliary agent: active molecular sieve 25-35%; main agent: CaO\ZnO, 45-55%;

Highly active pour point isomerization catalyst: carrier: Y-Al ₂ O ₃ , 40 to 45.5%; auxiliary agent: molecular sieve 45 to 55%; main agent: Pt/Pd, 0.5 to 5%.

As a preferred method, a method for producing alkylated biomass aviation fuel from waste grease includes:

(1)Hydrorefining reaction part

Add dimethyl disulfide to the inlet of the feed pump for the feed oil. After the feed oil is pressurized to 5.5-6.5 MPa (such as 6.0 MPa) through the hydrogenation feed pump, it is mixed with mixed hydrogen as the reaction feed. The mixed reaction feed is heated to about 190-210°C through a heat exchanger (reaction effluent/reactor feed heat exchanger), and then heated to 240-360°C (preferably 280-340°C) through a starting heating furnace ), it enters the hydrotreating reactor and reacts with the demetallization catalyst in the first bed of the reactor to remove a small amount of metal elements and phospholipids in the raw material, and performs hydrotreating in the lower two beds to remove the feed oil. A large amount of oxygen and a small amount of sulfur and nitrogen in the oil react to produce alkylated hydrocarbons, hydrogen sulfide, water, a small amount of ammonia and other reaction products. After heat exchange with the feed oil, the temperature is 240~280℃ ( For example, 260℃), the pressure is about 4.5~5.5MPa (for example, the pressure is 5.2MPa). Entering the high-efficiency stripping separator, high-pressure hydrogen of 5.5-6.5MPa (6.0MPa) greater than 3% of the feed amount is passed through the bottom of the high-efficiency stripping separator to strip the oil produced by the reaction at high pressure to remove short-term components. Chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide, ammonia and other substances. Before the gas phase material at the top of the high-efficiency stripping separator enters air cooling (high-pressure air cooling), desalted water is injected to wash away the ammonium salt generated during the air cooling stage to prevent ammonium salt from scaling and blocking the air cooling tube bundle. The cooled circulating hydrogen (40-45℃, 4.5-5.5MPa (preferably 5MPa)) removes the sulfur-containing sewage in the cold high-pressure separator, and the remaining small amount of circulating hydrogen containing hydrogen sulfide continues to be recycled to reduce the waste. Injection volume of methyl disulfide. Part of the sulfur-containing sewage produced by the cold high-pressure separator is reused to the water injection point, and part of it is discharged to the sewage treatment device when the ammonium salt concentration is high. A small amount of hydrocarbons are sent to the cold low-pressure separator. The circulating hydrogen is pressurized by the circulating hydrogen compressor and mixed with the raw oil again and enters the reaction system for recycling. The hydrogen lost in the reaction system is replenished by a new hydrogen compressor.

2) Hydroisomerization reaction part

The reaction of removing water vapor and hydrogen sulfide in the high-efficiency stripping separator produces oil (240-280°C, preferably 260°C). Under the action of its own pressure, it is mixed with the isomeric circulating hydrogen from the bottom outlet pipeline of the high-efficiency stripping separator. , reacts with isomerization to form biological heat exchange, and then is heated to about 300-360°C by the isomerization feed heating furnace, and then enters the isomerization reactor to selectively crack the molecules of long-chain hydrocarbons, from the original C18 , C16 is cracked into biomass aviation fuel components such as C9~C14. Isomerizes most normal paraffins into isoparaffins, thereby lowering the cold plugging point of the isomerized oil. The oil produced by the isomerization reaction is cooled by heat exchange in the isomerization feed heat exchanger, and then cooled to 40-45°C by high-pressure air cooling. After air cooling, the isomeric products enter the isomeric cold low fraction liquid, and the liquid phase directly enters the subsequent process for fractionation. The jet fuel component at 160-270℃ and the biodiesel component at 270-320℃ were extracted respectively. The naphtha part goes directly to the hydrogen production or fuel gas system with the dry gas. The gas phase system is compressed by the heterogeneous cycle hydrogen compressor and the cycle continues. The consumed hydrogen is replenished in time by the new hydrogen compressor. Isomerization consumes a small amount of hydrogen, and a new hydrogen compressor is shared with hydrorefining.

A device for producing alkylated biomass aviation fuel from waste grease, including:

A hydrofinishing reactor for carrying out the hydrofinishing reaction;

A stripping separator for performing the stripping and separation operation, the material inlet of the stripping separator is connected to the product outlet of the hydrorefining reactor through a pipeline, and the gas inlet is connected to a high-pressure hydrogen pipeline;

The gas phase post-processing unit cools the gas phase obtained by stripping and separation, and performs gas-liquid separation;

The circulating hydrogen compressor has an inlet connected to the gas phase outlet of the gas phase post-processing unit, and the recovered hydrogen containing hydrogen sulfide is used as circulating hydrogen and supplementary hydrogenation to be used as the mixed hydrogen;

An isomerization reactor for carrying out the isomerization reaction, the raw material inlet and the liquid outlet of the stripping separator are connected through a pipeline;

The isomerization product post-processing unit is connected to the product outlet of the isomerization reactor to finally obtain the alkylated biomass aviation fuel;

Heat exchanger I is thermally connected between the product pipeline of the hydrorefining reactor and the raw material pipeline of the hydrorefining reactor to realize heat exchange;

Heat exchanger II is thermally connected between the product pipeline of the isomerization reactor and the feed pipeline of the hydrotreating reactor to achieve heat exchange.

Preferably, the gas phase post-processing unit includes: a high-pressure air cooler for air-cooling the gas phase obtained by stripping and separation, a cold high-pressure separator for gas-liquid separation of the air-cooled materials of the high-pressure air cooler; the cold high-pressure separator The separated water phase is partially returned to the high-pressure air cooler and partially output to the generated water pump of the water treatment unit. The hydrogen containing hydrogen sulfide separated by the cold high-pressure separator is pressurized by a circulating hydrogen compressor and recycled. The short-chain alkanes separated by the cold high-pressure separator are combined with the isomerization products and recovered.

Preferably, the isomerized product post-processing unit includes: a heterogeneous high-pressure air cooler for air-cooling the isomerized materials, and a cold low-pressure separator for gas-liquid separation of the air-cooled materials. The cold low-pressure separator also receives the short-chain alkanes obtained from the cold high-pressure separator; part of the hydrogen obtained from the cold low-pressure separator is recycled and used, and part of the hydrogen is discharged to the fuel system; the liquid material obtained from the cold low-pressure separator is fractionated to obtain respectively Jet fuel components, biodiesel components and naphtha components.

The waste oils and fats of the present invention may be one or more of waste catering oil, gutter oil, swill oil, palmitated oil, coconut oil, palm oil, etc.

Preferably, the raw material oil is waste grease mainly containing C16-C18, the acid value in the raw material oil is 15-25 mg/g; the iodine value is 80-120g/100g.

Compared with the existing technology, the process of hydrorefining and isomerizing high-oxygen waste grease to produce biomass aviation fuel that we independently developed does not require multiple cooling, depressurizing, and then heating and pressurizing processes, which reduces the number of phase changes. Improved energy utilization and reduced energy consumption. The products generated by the refining reaction are directly fed into the high-efficiency stripping separator for stripping and gas-liquid two-phase separation. It makes full use of the heat generated by the hydrorefining itself and the high pressure of high-pressure hydrogen to completely remove hydrogen sulfide, water vapor, Ammonia etc. At the same time, the generated oil at the bottom of the high-efficiency stripping separator enters the isomerization reaction system under self-pressure. The generated oil after the reaction directly enters fractionation for rectification. There is no H ₂ S and no additional power equipment is required, which accordingly reduces the cost of some equipment pipes. Invest. The gas phase at the top is cooled by high-pressure air cooling to about 40-45°C and enters the cold high temperature zone to remove acidic water, circulate hydrogen and then return to the compressor inlet for pressurized circulation.

According to the technical solution of the present invention, the products are alkylated biomass aviation fuel, biodiesel and biomass naphtha, and the raw materials are waste animal and vegetable oils and fats. Such products have positive significance for reducing carbon emissions, and some European Union The national mandatory policy has increased the proportion of biomass aviation fuel in aviation fuel, which has good policy incentives and broad market prospects.

The beneficial effects of the present invention are reflected in:

Through low-pressure sulfur injection, the hydrorefining catalyst maintains high activity during the deoxygenation reaction.

2) Recover circulating hydrogen to the greatest extent, reduce the injection volume of dimethyl disulfide, and save chemical costs.

3) In the high-efficiency stripping separator, hydrogen sulfide, water vapor, ammonia, etc. in the reaction products are removed to the maximum extent through hydrogen stripping.

4) Ensure that the hydrogen sulfide content of the reaction product before entering the isomerization reactor is less than 2ppm, thereby effectively protecting the precious metal catalyst in the isomerization system. Extend the service life of desulfurizers in heterogeneous systems.

5) The oil generated from the reaction at the bottom of the high-pressure gas separator has a relatively high temperature and does not require excessive heat exchange or a high-pressure feed pump. It is pressed to the isomerization system by its own pressure. The investment cost of moving equipment is reduced and the power loss is reduced.

6) The reaction generates hydrogen sulfide, water vapor, and ammonia in the oil, which reduces the problem of clothing in the oil phase pipeline and greatly reduces the investment cost of upgrading equipment materials.

7) The appropriate hydrogen-to-oil ratio reduces the power burden of the gas-phase power system, saving energy and protecting the environment.

8) The use of hydrogen mixing in front of the furnace reduces the chance of oil coking in the furnace tube due to excessive temperature during the start-up stage.

9) Since waste animal and vegetable oils have strong heat of reaction, the reasonable heat exchange grid of this process not only ensures efficient heat exchange of the system, but also the heat of reaction is enough to ensure the heating heat of the raw oil after startup, without the need for additional Using natural gas for heating is energy-saving and environmentally friendly, minimizing processing costs, reducing carbon emissions, and ensuring the profitability of the process.

10) The water separated by cold high fractionation can be effectively reused, which can reduce safety problems caused by ammonium salt crystallization and corrosion, and can also reduce sewage treatment costs.

Description of the drawings

Figure 1 is a system diagram for producing alkylated biomass aviation fuel from waste grease used in some embodiments of the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific examples. The examples can enable researchers to better understand the present invention, but do not limit the present invention in any form.

Examples 1 to 3

Figure 1 is a system diagram for producing alkylated biomass aviation fuel from waste grease in this embodiment, including a new hydrogen compressor 101, a feed oil feed pump 102, a hydrorefining reactor 103, a heat exchanger 104, Hydrogen heating furnace 105, stripping separator 106, high-pressure air cooler 107, cold high-pressure separator 108, generated water pump 109, circulating hydrogen compressor 110, heat exchanger II 111, isomerization heating furnace 112, isomerization reactor 113 , heterogeneous high-pressure air cooler 114, cold low-pressure separator 115, heterogeneous cycle hydrogen compressor 116.

According to the material direction, the hydrotreating reactor 103, the stripping separation operation 106, and the isomerization reactor 113 are connected in sequence. The outlet of the raw oil feed pump 102 is connected to the low-temperature pipeline inlet of the heat exchanger I 104 through a pipeline, and the low-temperature pipeline outlet of the heat exchanger I 104 is connected to the feed port of the hydrogenation heating furnace 105 through a pipeline, and the hydrogenation heating The discharge port of the furnace 105 is connected to the feed port of the hydrotreating reactor 103 through a pipeline. The outlet of the hydrorefining reactor 103 is connected to the high-temperature pipeline inlet of the heat exchanger 1104 through a pipeline, and the high-temperature pipeline outlet of the heat exchanger 1104 is connected to the material inlet of the stripping separation operation 106 through a pipeline. The stripping separation operation 106 is also provided with a new hydrogen feeding port. The bottom of the stripping separation operation 106 is the reaction generated oil outlet, which is connected to the low-temperature pipeline inlet of the heat exchanger II 111 through a pipeline, and the low-temperature pipeline outlet of the heat exchanger II 111 is connected to the inlet of the heterogeneous heating furnace 112 through a pipeline. The outlet of the isomerization heating furnace 112 is connected to the feed port of the isomerization reactor 113 through a pipeline. The top of the stripping and separation operation 106 is a gas phase outlet, which is connected to the high-pressure air cooler 107 and the cold high-pressure separator 108 in sequence through pipelines. A part of the wastewater separated by the cold high-pressure separator 108 is circulated to the inlet of the high-pressure air cooler 107 using the generated water pump 109 The other part of the pipeline is sent directly to the water treatment unit. The hydrogen containing hydrogen sulfide recovered by the cold high-pressure separator 108 is output through its hydrogen outlet, connected to the circulating hydrogen compressor 110 through a pipeline, and then returned to the outlet of the raw oil feed pump 102 to be mixed with raw oil, new hydrogen, etc. Return to hydrotreater. The outlet of the isomerization reactor 113 is located at the bottom and is connected to the high-temperature pipeline inlet of the heat exchanger II 111 through a pipeline. The high-temperature pipeline outlet of the heat exchanger II 111 is connected to the inlet of the heterogeneous high-pressure air cooler 114 through a pipeline. The outlet of the structural air cooler 114 is connected to the cold low-pressure separator 115 through a pipeline.

During the actual reaction, dimethyl disulfide (generally 0.005% of the feed oil) is added to the inlet of the feed oil feed pump. After the feed oil is pressurized to 6.0MPa by the hydrogenation feed pump, it is mixed with mixed hydrogen as a reaction. Feed. The mixed reaction feed is heated to about 190-210°C through a heat exchanger (reaction effluent/reactor feed heat exchanger), and then heated to about 280-340°C by the start-up heating furnace before entering hydrofining. The reactor reacts with the demetallization catalyst in the first bed of the reactor to remove a small amount of metal elements and phospholipids in the raw material. Hydrofining reactions are carried out in the lower two beds to remove a large amount of oxygen and a small amount of oxygen in the raw oil. Elements such as sulfur and nitrogen react to produce alkylated hydrocarbons, hydrogen sulfide, water, a small amount of ammonia and other reaction products. After exchanging heat with the feed oil, the temperature is 260°C and the pressure is about 5.2MPa. Entering the high-efficiency stripping separator, the bottom of the high-efficiency stripping separator passes 6.0MPa high-pressure hydrogen of more than 3% of the feed amount, and performs high-pressure stripping on the reaction oil to remove short-chain hydrocarbons, hydrogen, Dry gas, liquefied gas, water vapor, hydrogen sulfide, ammonia and other substances. Before the gas phase material at the top of the high-efficiency stripping separator enters air cooling (high-pressure air cooler 107), desalted water is injected to wash away the ammonium salt generated during the air cooling stage to prevent ammonium salt from scaling and blocking the air cooling tube bundle. The cooled circulating hydrogen (40-45°C, 5.0MPa) removes the sulfur-containing sewage in the cold high-pressure separator 108, and the remaining small amount of circulating hydrogen containing hydrogen sulfide continues to be recycled to reduce the concentration of dimethyl disulfide. Injection volume. Part of the sulfur-containing sewage produced by the cold high-pressure separator is reused to the water injection point, and part of it is discharged to the sewage treatment device when the ammonium salt concentration is high. A small amount of hydrocarbons is sent to the cold low-pressure separator 115. The circulating hydrogen is pressurized by the circulating hydrogen compressor 110 (the pressure is 6.0 MPa) and mixed with the raw oil again and enters the reaction system for recycling. The hydrogen lost in the reaction system is replenished by a new hydrogen compressor (controlled by the pressure of the hydrofining reactor 103).

In the high-efficiency stripping separator (stripping separation operation 106), the reaction of removing water vapor and hydrogen sulfide generates oil (260°C). Under the action of its own pressure, the bottom outlet pipeline of the high-efficiency stripping separator and the isomeric circulating hydrogen Mix, exchange heat with the isomerization reaction product, and then pass through the isomerization feed heating furnace (isomerization heating furnace 112) to heat to about 300-360°C, and then enter the isomerization reactor 113 to convert the molecules of long-chain hydrocarbons into Selective cracking is carried out to crack the original C18 and C16 into biomass aviation fuel components such as C9~C14. Isomerizes most normal paraffins into isoparaffins, thereby lowering the cold plugging point of the isomerized oil. The oil produced by the isomerization reaction is cooled by heat exchange in the isomerization feed heat exchanger, and then cooled to 40-45°C in the isomerization high-pressure air cooler 114. After air cooling, the isomeric products enter the isomeric cold low-pressure separator 115 for liquid separation, and the liquid phase directly enters the subsequent process for fractionation. The jet fuel component at 160-270℃ and the biodiesel component at 270-320℃ were extracted respectively. The naphtha part goes directly to the hydrogen production or fuel gas system with the dry gas. The gas phase separated by the cold low-pressure separator 115 is compressed by the isomerization cycle hydrogen compressor 116 (pressure is 3.5MPa), continues to circulate, and is mixed with new hydrogen and then mixed with the oil phase at the bottom of the stripping separation operation 106 and enters the heat exchanger II 111 . The consumed hydrogen is replenished in time by the new hydrogen compressor. Isomerization consumes a small amount of hydrogen, and a new hydrogen compressor is shared with hydrorefining.

1) The reaction stage is mainly realized by the catalyst in the hydrofining reactor and the hydroisomerization reactor (isomerization reactor 113). There are three types of deoxygenation reactions: hydrodeoxygenation (HDO), hydrodecarbonylation (HDCO) and decarboxylation (HDCO2). After deoxygenation of the raw material, alkanes, water, carbon monoxide and carbon dioxide are produced. The raw material contains a small amount of sulfur and nitrogen, which are removed during the hydrorefining process to generate hydrogen sulfide and ammonia. Normal alkanes generate branched isoparaffins under the combined action of molecular sieves and active metal Pt/Pd catalysts. Due to the irregularity of isoparaffin molecules, the fluidity of the product is improved, the freezing point of the alkanes is reduced, and the isomerization reaction Along with the side reaction of a small amount of carbon chain breakage, alkanes with a smaller carbon number are generated. This alkane component is exactly the component of aviation fuel and has excellent indicators, which are better than fossil aviation kerosene components. Its freezing point is <-50℃, and its product performance is far ahead in the world. Sulfur, nitrogen, and oxygen levels are all below 1 ppm, fully supporting the policy of carbon emission reduction.

2) Separation is mainly achieved by high-efficiency stripping separator and high and low separation. The high-efficiency gas separator separates hydrogen sulfide and water vapor in the purified reaction product to the greatest extent, ensuring that the heteronoble metal catalyst is free from any pollution and operates efficiently.

3) Temperature raising and cooling are mainly achieved by heat exchangers and air cooling.

4) Product separation is mainly achieved by fractionating towers.

5) The key point is the high-efficiency stripping separator. This equipment is the bridge and hub between two reaction systems with completely different conditions: hydrorefining and isomerization. While protecting isomeric precious metals from being polluted and poisoned by hydrogen sulfide, the greater significance of this equipment is to further strip the hydrogen sulfide and water vapor in the oil produced by the reaction to the circulating cold high-pressure separator for separation of sulfur-containing sewage. It reduces the amount of dimethyl disulfide added in the refining system and effectively reduces the risk of corrosion of the generated oil in subsequent pipelines. The energy-saving effect is more prominent in terms of power loss.

The following table shows the analysis data of the raw material oil used in this example:

Table 1

Physical and chemical parameters	80℃density	Moisture	insoluble impurities	melting point	carbon residue	Acid value
unit	g/cm 3	%	%	℃	%	mg/g
numerical value	0.9057	0.05	0.023	30.03	0.42	20.54
Physical and chemical parameters	Iodine value	Saponification value	chlorine	sulfur	nitrogen	viscosity
unit	g/100g	mg/g	ppm	ppm	ppm	mm 2 /s
numerical value	96.62	198	10.9	66.35	87.8	12.06

The following table shows the analysis data of the hydrogen gas sample from the top circulation of the high-efficiency gas separator in this example:

Table 2

The following table shows the new hydrogen analysis data used in this example:

table 3

H 2	CO 2	CO	CH 4	C 2 H 6	O 2	N 2
%	ppm	ppm	ppm	ppm	ppm	ppm
99.99	0.19	0.01	0.88	0	7.02	61

The following table shows the naphtha component analysis data obtained in this example:

Table 4

The following table shows the component analysis data of biomass aviation fuel obtained in this example:

table 5

The following table shows the operating conditions of the reaction system in this example:

Table 6

​	Pressure(MPa)	Temperature(℃)	Airspeed (h - 1)	Hydrogen to oil ratio
Hydrorefining	3.5～6.0	240～360	0.4～2.0	1200:1
Isomerism depressurization	1.5～3.5	240～370	0.2～0.8	600:1

The following table shows the yield of each embodiment: (The pressure of the isomerization reactor is constant at 3.5MPa, the temperature is constant based on the reactor inlet temperature of 345°C, the hydrogen-to-oil ratio is constant at 600:1, and the three space velocities with different reactions are changed by 0.6h. ^-1 ; the hydrotreating reactor parameters remain unchanged: pressure (5.4MPa); temperature (350°C); space velocity (1.0h ^- 1).

​	Example 1	Example 2	Example three
airspeed	1.8h -1	1.2h -1	0.6h -1
CO+CO2	0.23	0.37	0.49
Dry air	0.15	0.98	1.39
Liquefied gas	0.42	1.83	2.51
Naphtha	0.98	3.88	3.99
biojet fuel	40.6	50.8	67.1
biodiesel	44.8	27.8	10.6

The following table shows the catalysts used in the examples:

It can be seen from the above analysis that the present invention uses a high-efficiency stripping separator to directly strip the products generated by the refining reaction and separate the gas-liquid phases, completely removing hydrogen sulfide and water vapor, and the generated oil at the bottom of the high-efficiency separator enters under pressure. Heterogeneous reaction system effectively reduces process energy consumption and production procedures.

Claims (16)

1. A method for producing alkylated biomass aviation fuel from waste oil, which is characterized by using raw oil and mixed hydrogen as the main raw materials, including sequential and continuous hydrofining reactions, stripping separation and isomerization reactions. The product obtained by the structural reaction is cooled, gas-liquid separated and fractionated to obtain the aviation fuel;

   The oil phase material obtained by the hydrorefining reaction is directly subjected to the stripping separation after heat exchange with the raw material of the hydrorefining reaction;

   The stripping and separation operation uses high-pressure hydrogen as the stripping working fluid, and the hydrogen containing hydrogen sulfide recovered by stripping and separating is used as circulating hydrogen and is combined with supplementary hydrogenation to be used as the mixed hydrogen; the oil phase material obtained by stripping and separating is mixed with the foreign matter. The product materials of the isomerization reaction are directly subjected to the isomerization reaction after heat exchange.
2. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that the hydrorefining reaction conditions are: pressure is 3.5~6MPa, temperature is 240~360°C, and space velocity is 0.4~2.0h ^-1 , hydrogen to oil ratio is 1000~1400:1 (V/V).
3. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that the operating conditions of stripping separation are: stripping temperature is 200-280°C and pressure is 4-5.5MPa.
4. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that the reaction conditions of the isomerization reaction are: pressure is 1.5~3.5MPa, temperature is 240~370°C, and space velocity is 0.2 ~0.8h ^-1 , hydrogen to oil ratio is 500~700:1 (V/V).
5. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that the dimethyl disulfide, feed oil and mixed hydrogen are mixed first, and then the hydrorefining reaction is performed.
6. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that the hydrorefining reaction includes deoxygenation reaction, desulfurization reaction, denitrification reaction and demetallization reaction using hydrogen. of one or more.
7. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that, after heat exchange between the raw material for the hydrorefining reaction and the oil phase material obtained by the hydrorefining reaction, the temperature rises to 190-210°C, and then Optional reheating to 280~340℃.
8. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that, after heat exchange between the oil phase material obtained by the hydrorefining reaction and the raw material of the hydrorefining reaction, the temperature drops to 240-280°C, The pressure is 4.5~5.5MPa.
9. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that the amount of hydrogen used in stripping separation is 5.5 to 6.5 MPa; the added amount is 3 to 10% of the feed amount.
10. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that the gas phase obtained by stripping and separation is cooled to 40-50°C by a high-pressure air cooler, and then enters a cold high-pressure separator for cold high-pressure separation. A part of the hydrogen containing hydrogen sulfide separated by the cold high-pressure separator is pressurized and used as the circulating hydrogen. The short-chain hydrocarbons separated by the cold high-pressure separator and the cooling material obtained by the isomerization reaction are combined into the gas-liquid separation. The cold high-pressure separator A part of the water phase obtained from the separator is combined with newly injected water and returned to the high-pressure air cooler for desalination.
11. The method for producing alkylated biomass aviation fuel from waste grease according to claim 10, wherein the content of hydrogen sulfide in the circulating hydrogen is 200 to 700 ppm.
12. The method for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that the oil phase obtained by stripping and separation is mixed with isomeric circulating hydrogen and supplementary hydrogenation, and then reacts with isomerization to form a biological heat exchanger. 260~350℃; then heated to 300~360℃ by heating equipment; the product obtained by the isomerization reaction first exchanges heat with the oil phase obtained by stripping and separation, and then is cooled to 40~45℃ by high-pressure air cooling, and then Gas-liquid separation is performed, and part of the hydrogen obtained is reused as isomerized circulating hydrogen.
13. The method for producing alkylated biomass aviation fuel from waste oil according to any one of claims 1 to 12, characterized in that the raw oil is waste oil mainly containing C16 to C18, and the acid value in the raw oil is 15 ~25mg/g; iodine value is 80~120g/100g.
14. The method for producing alkylated biomass aviation fuel from waste grease according to any one of claims 1 to 12, characterized in that, in the hydrofining reaction, three layers of supported catalysts are used in sequence from the raw material inlet, and they are simultaneously Low-activity demetallization catalyst, active demetallization catalyst, and high-activity demetallization catalyst with desulfurization and deoxidation functions. The main agent of the three catalysts is Co-Mo-Ni;

    In the isomerization reaction, two layers of supported catalysts are used in sequence from the raw material inlet, which are active oxidation state metal desulfurization catalysts and high activity condensation reducing isomerization catalysts. The main agent of the active oxidation state metal desulfurization catalyst is CaO\ZnO. , the main agent of the high activity pour point isomerization catalyst is Pt/Pd.
15. The method for producing alkylated biomass aviation fuel from waste grease according to claim 14, characterized in that the catalyst compositions are as follows:

    Low activity demetallization catalyst: carrier: Y-Al ₂ O ₃ , 3 to 5%; auxiliary: supported molecular sieve 75 to 85%; main agent: Co-Mo-Ni metal component, 10 to 20%;

    Highly active demetallization catalyst: carrier: Y-Al ₂ O ₃ , 5 to 8%; additive: supported molecular sieve 60 to 70%; main agent: Co-Mo-Ni metal component, 25 to 35%;

    Highly active demetallization catalyst: carrier: mixture of alkaline metal oxide and Y-Al ₂ O ₃ , 10 to 20%; auxiliary: active molecular sieve 45 to 55%; main agent: Co-Mo metal component, 35 to 45 %;

    Active oxidation state metal desulfurization catalyst: carrier: Y-Al ₂ O ₃ , 15-25%; auxiliary agent: active molecular sieve 25-35%; main agent: CaO\ZnO, 45-55%;

    Highly active pour point isomerization catalyst: carrier: Y-Al ₂ O ₃ , 40 to 45.5%; auxiliary agent: molecular sieve 45 to 55%; main agent: Pt/Pd, 0.5 to 5%.
16. A system for producing alkylated biomass aviation fuel from waste grease according to claim 1, characterized in that it includes:

    A hydrofinishing reactor for carrying out the hydrofinishing reaction;

    In the stripping separator that performs the stripping and separation operation, the material inlet is connected to the product outlet of the hydrorefining reactor through a pipeline, and the gas inlet is connected to a high-pressure hydrogen pipeline;

    The gas phase post-processing unit cools the gas phase obtained by stripping and separation, and performs gas-liquid separation;

    The circulating hydrogen compressor has an inlet connected to the gas phase outlet of the gas phase post-processing unit, and the recovered hydrogen containing hydrogen sulfide is used as circulating hydrogen and supplementary hydrogenation to be used as the mixed hydrogen;

    An isomerization reactor for carrying out the isomerization reaction, the raw material inlet and the liquid outlet of the stripping separator are connected through a pipeline;

    The isomerization product post-processing unit is connected to the product outlet of the isomerization reactor to finally obtain the alkylated biomass aviation fuel;

    Heat exchanger I is thermally connected between the product pipeline of the hydrorefining reactor and the raw material pipeline of the hydrorefining reactor to realize heat exchange;

    Heat exchanger II is thermally connected between the product pipeline of the isomerization reactor and the feed pipeline of the hydrotreating reactor to achieve heat exchange.

Images