CN107974266B

CN107974266B - Method and system for producing aviation fuel components from waste oil

Info

Publication number: CN107974266B
Application number: CN201610941923.6A
Authority: CN
Inventors: 聂红; 杜泽学; 渠红亮; 曾建立; 王锦业; 张伟; 吴昊; 王鲁强; 王海京
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2016-10-25
Filing date: 2016-10-25
Publication date: 2020-06-12
Anticipated expiration: 2036-10-25
Also published as: CN107974266A

Abstract

The invention relates to a method and a system for producing aviation fuel components from waste grease, which comprises the following steps: the invention takes waste grease as raw material to react with methanol, replace glycerin, remove chlorine and metal in the raw material and reduce the acid value of the raw material, and then produces aviation fuel components meeting the product requirements through hydrodeoxygenation and selective cracking reaction, thus realizing the effective utilization of waste grease resources.

Description

Method and system for producing aviation fuel components from waste oil

Technical Field

The invention belongs to a production method of biofuel, and particularly relates to a method and a system for producing aviation fuel components from waste oil.

Background

With the traditional fossil energy supply becoming tight and the pressure for carbon dioxide emission reduction increasing, the development of renewable, clean alternative energy has become a global consensus.

Liquid fuels, such as gasoline, diesel and aviation fuels, are a major source of atmospheric carbon dioxide emissions. These liquids are mostly derived from oil, gas and coal. Biomass-derived fuels absorb carbon dioxide during growth relative to fossil fuels, and carbon dioxide emissions can be effectively reduced compared to fossil fuels. Thus, biofuel is considered as one of the most ideal ways for the transportation industry to reduce carbon dioxide emissions.

Among the raw materials for preparing biofuel, animal and vegetable fats and oils are a main group of raw materials. However, the principle of not competing with human and grain and land must be followed when developing the biofuel. The benefit of inedible, waste oils and fats is therefore a necessary choice for the development of biofuels.

The waste oil refers to oil waste which is produced in the processes of processing and edible consumption of natural oil (vegetable oil and animal fat) and loses edible value, and comprises leftovers produced in the process of producing edible oil from oil plants, frying residual oil and kitchen residual oil produced in edible oil used by resident families, hotels, catering industries and food production enterprises, animal fat by-produced in the process of producing and processing meat, edible oil with a shelf life exceeding, and the like. Conservative estimates are that more than 1000 million tons of waste grease are produced annually in china.

Improper disposal of waste grease can become a serious source of pollution, polluting land, water and atmosphere. The waste grease is used as an animal feed additive or used for producing a detergent product, but the use is found to extend the harm to human beings, only the harmless treatment can be carried out on the waste grease by pollutants, but the treatment difficulty is high, and the cost is high.

The conventional process for converting fats and oils into liquid fuels is a transesterification method, and the fats and oils can be converted into fatty acid methyl esters and glycerin by transesterification with methanol and fats and oils, and the products are usually fatty acid methyl esters (also called first generation biodiesel). The ester exchange method mainly comprises the following steps: acid catalysis, base catalysis, enzyme catalysis, supercritical technology and the like. However, the reaction catalyzed by acid and alkali has higher requirements on raw materials, waste oil cannot be directly treated, and the supercritical technology can directly treat the waste oil.

However, when the waste oil is adopted to produce the biodiesel, the acid value of the biodiesel often cannot meet the requirements of product quality standards, such as European and American standards and newly revised national standards to be released in China have higher requirements on the acid value of the product, namely not more than 0.5 mgKOH/g. Further treatment is required to reduce the acid value of the product, increasing the investment and operating costs of the plant. Moreover, poor low temperature fluidity of fatty acid methyl esters limits their use in colder environmental conditions, while the presence of carbon-carbon double bonds reduces the stability of fatty acid methyl esters. Higher NOx emissions result during combustion due to the presence of oxygen atoms in the fatty acid methyl esters. The fatty acid methyl ester is required to be mixed with the traditional diesel oil for use in the using process, and the mixing proportion of the fatty acid methyl ester is generally not more than 10 percent.

The other method for converting the grease into the liquid fuel is a hydrogenation method, the grease is converted into the hydrocarbon fuel through hydrodeoxygenation, compared with the first generation biodiesel, the biodiesel does not contain oxygen elements, has a cetane number as high as 70-100, has better storage stability, and can be blended with the traditional petroleum-based diesel in any proportion. In addition, the aviation industry is under double pressure on carbon dioxide abatement and carbon taxes, placing great promise on biomass-derived aviation fuels, and considering biofuels as the only option to achieve the carbon dioxide abatement goal.

However, the waste oil has various types, complex sources, dispersed channels and unstable impurity composition and content, and can not be directly subjected to fixed bed hydrogenation treatment. If the content of free fatty acid in the waste oil is wide and is from 1% to more than 80%, the requirement of equipment corrosion protection can be increased due to the fact that the content of the free fatty acid is too high; the waste oil also contains various impurities, including inherent phospholipid in the oil, colloid, soap, heteroatom organic matters and the like generated by oxidation in the collection processing process; particularly, the existence of chlorine-containing compounds has higher hazard, and inorganic acid can be generated in the subsequent hydrogenation process, so that the equipment corrosion is aggravated, and safety accidents are induced. Therefore, it is necessary to reduce the acid value of the raw material and remove impurities such as colloid, metal ion and chlorine from the raw material by some methods before hydrogenation, so as to reduce the corrosion of equipment, prolong the service life of the catalyst and improve the continuity of the production. In the process for the production of hydrocarbon fractions from mixtures of biological origin as disclosed in CN101583694, it is required to subject the feedstock to a pretreatment prior to hydrodeoxygenation, which comprises absorption, treatment with ion exchange resins or with weakly acidic detergents. CN101233212 discloses a process for the preparation of diesel range hydrocarbons, wherein the alkali metal or alkaline earth metal in the feedstock is limited to less than 10 mg/kg.

CN102504866 discloses a method for preparing biodiesel from kitchen waste oil. The method adopts a water washing method to pretreat the kitchen waste oil so as to remove metals in the raw materials. Then, carrying out hydrodemetallization, degumming and partial deoxidation reactions on the pretreated raw material; mixing with mineral oil, performing two-stage hydrogenation, and hydrocracking or isomerization reaction to improve product properties. The kitchen waste oil is pretreated by a water washing method, only part of metals in the raw materials can be removed, and chlorine in the raw materials and the acid value of the raw materials are not improved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a method for producing aviation fuel components from waste grease.

The method provided by the invention comprises the following steps:

(1) the waste oil methyl esterification unit is used for carrying out alcoholysis reaction on the waste oil and methanol after mixing, boosting and heating to obtain crude glycerol and crude methyl ester, and the crude methyl ester is subjected to flash evaporation to obtain refined methyl ester;

(2) a hydrotreating reaction unit, which is used for contacting the refined methyl ester obtained in the step (1) with a hydrotreating catalyst in the presence of hydrogen, and carrying out a deoxidation reaction under the hydrotreating condition to obtain a hydrotreating product; the hydrotreating catalyst comprises a carrier of composite alumina and a hydrogenation active component loaded on the carrier, wherein the hydrogenation active component comprises at least one metal component selected from VIII group and at least one metal component selected from VIB group, and the alumina carrier comprises a step of water vapor treatment in the preparation process;

(3) a hydro-conversion reaction unit, which is used for contacting the hydro-processed product obtained in the step (2) with a hydro-conversion catalyst in the presence of hydrogen and carrying out selective cracking reaction under the hydro-conversion condition to obtain a hydro-converted product;

(4) and (4) a separation and fractionation unit, wherein the oil generated by the hydroconversion in the step (3) is separated and fractionated to obtain a kerosene component and a diesel component.

The content of the invention is further illustrated as follows:

(1) methyl esterification unit for waste oil

Mixing, boosting and heating the waste oil and methanol, and carrying out alcoholysis reaction to obtain crude glycerol and crude methyl ester; refining the crude glycerol to produce a glycerol product; and flash evaporating the crude methyl ester to obtain refined methyl ester and heavy grease. After methyl esterification reaction, glycerin in the oil is converted into glycerol by methanol, and impurities of the raw material are enriched in the heavy oil, so that the glycerol is replaced, chlorine and metals in the raw material are removed, and the acid value of the raw material is reduced.

The operating conditions of the methyl esterification unit of the waste oil and fat are as follows: the temperature of alcoholysis reaction between the waste oil and methanol is 180-320 ℃, preferably 220-300 ℃, and more preferably 240-280 ℃; the reaction pressure is 4-10 MPa, preferably 5-8 MPa; the mass ratio of the methanol to the grease is 0.2-1: 1, preferably 0.3-0.7: 1; the reaction time is 30-120 min, preferably 60-90 min.

According to the method provided by the invention, the mixed material after alcoholysis reaction enters a rectifying tower, and methanol is extracted by adopting a rectifying method, wherein the rectifying tower can be a packed tower or a plate tower, and the packed tower is preferred.

In the invention, a crude methyl ester glycerol settling separator and a crude methyl ester flash evaporation container are arranged in a methyl esterification unit of waste oil, methanol is separated from a mixed material after alcoholysis reaction and then the mixed material enters the crude methyl ester glycerol settling separator, the separator is continuously operated, and the operation conditions are as follows: keeping the temperature of the material at 40-80 ℃, preferably 50-70 ℃; the preferred retention time is 0.5-3 h, and the preferred retention time is 1-2 h; after the settling is finished, the crude methyl ester leaves from the upper part of the separator and enters a crude methyl ester flash evaporation container, and the crude glycerin leaves from the lower part of the separator and can be further refined; and carrying out flash evaporation treatment on the crude methyl ester to obtain refined methyl ester, wherein a flash evaporation container of the crude methyl ester is a flash evaporation tank or a flash evaporation tower.

According to the method provided by the invention, the flash evaporation of the crude methyl ester aims to realize the separation of the methyl ester and the heavy grease to obtain the refined methyl ester. The crude methyl ester flash vessel is a flash drum or a flash tower, and the operating conditions of the flash tower are as follows: the temperature is 220-350 ℃, and preferably 260-320 ℃; the pressure is 2 to 0.3kPa, preferably 1.5 to 0.5 kPa.

The content of fatty acid methyl ester in the obtained refined methyl ester exceeds 95 percent, the content of sulfur is not more than 10 mu g/g, the content of Cl is not more than 1 mu g/g, and the sum of the contents of various metal ions is not more than 2 mu g/g.

In the method provided by the invention, the waste oil is oil waste which is generated in animal and vegetable oil processing and edible consumption and is not suitable for eating again. Including fatty acid, acidified oil and the like generated in the process of producing edible oil from oil; various waste cooking oils such as frying residual oil, kitchen residual oil and hogwash oil generated in edible oil are used by resident families, hotels, catering industries and food production enterprises; animal fat as by-product in meat production and processing, edible oil with shelf life longer than that of meat.

In the hydrogenation of fats and oils, glycerin groups in the fats and oils are hydrogenated to produce propane, and if propane is recovered, the investment in facilities is increased. The glycerol is an important chemical raw material, can be directly used, and can also be used for preparing other chemical products through biological and chemical processing. Methanol is used as a chemical raw material, has wide sources and is cheaper than glycerin. The value of the waste oil can be improved by replacing high-value glycerol with low-price methanol, and the production cost of the biofuel is reduced; and the pretreatment of the waste grease can be realized through the ester exchange reaction, so that the requirement of the subsequent hydrogenation process is met.

(2) Hydroprocessing reaction unit

And (2) contacting the refined methyl ester obtained in the step (1) with a hydrotreating catalyst in the presence of hydrogen, and performing a deoxidation reaction under the hydrotreating condition to obtain a hydrotreating product.

The reaction conditions of the hydrotreating reaction unit are as follows: reaction temperature is 200-400 ℃, and hydrogen partial pressure is1.0-10.0 MPa, and the liquid hourly space velocity is 0.5-10.0 h^-1Hydrogen to oil volume ratio of 500 to 1500Nm³/m³. The mixed material is subjected to hydrodeoxygenation, olefin saturation, hydrodesulfurization and other reactions under the reaction conditions and under the action of a catalyst, and the reactions are strong exothermic reactions.

In a preferred embodiment of the invention, part of the liquid phase material in the hydrotreating product is recycled to the inlet of the hydrotreating reaction unit, and the mass ratio of the refined methyl ester to the recycled liquid phase material is 1: 2-1: 6.

According to the method provided by the invention, the hydrotreating catalyst takes alumina as a carrier and hydrogenation active components loaded on the carrier, wherein the hydrogenation active components comprise at least one metal component selected from VIII group and at least one metal component selected from VIB group. The preparation process of the alumina carrier comprises a step of water vapor treatment. Preferably, the alumina carrier does not include a calcination step in the preparation process. During hydrodeoxygenation of the feedstock, large amounts of water are formed and the presence of water vapour can affect the stability of the catalyst, especially the catalyst support. According to the method provided by the invention, the carrier of the used catalyst is treated by water vapor without roasting, and the property of the carrier can be obviously stabilized, so that the influence of water generated in the hydrotreating reaction process on the hydrotreating catalyst is avoided.

According to the method provided by the invention, the preparation step of the hydrotreating catalyst comprises the following steps:

(1) mixing, molding and drying hydrated alumina;

(2) carrying out water vapor treatment to obtain a carrier;

(3) and (3) immersing the carrier obtained in the step (2) into a prepared aqueous solution containing a hydrogenation active component, and then drying and roasting to obtain the hydrotreating catalyst.

The hydrated alumina is pseudo-boehmite. The drying conditions of the step (1) are as follows: the temperature is 80-200 ℃, and the time is 1-24 hours.

The conditions of the steam treatment step of step (2) include: the temperature is 450-750 ℃, the time is 4-8 hours, and the steam flow is 0.5-5.0 standard cubic meter/kilogram carrier per hour.

The dipping conditions in the step (3) are as follows: the temperature is 20-100 ℃, and the time is 1-24 hours.

The roasting conditions in the step (3) are as follows: the temperature is 400-650 ℃, and the time is 2-6 hours.

In the hydrotreating catalyst, preferably, the group VIII metal component is cobalt and/or nickel, the group VIB metal component is molybdenum and/or tungsten, and the content of the group VIII metal component is 1 to 10 wt%, and the content of the group VIB metal component is 10 to 45 wt%, based on oxides and based on the catalyst.

The aqueous solution containing the hydrogenation active component, such as an aqueous solution of compounds of cobalt, molybdenum, nickel and tungsten, can be prepared by a conventional method. The compounds of cobalt, molybdenum, nickel and tungsten are respectively selected from one or more soluble compounds thereof. Wherein the compound of molybdenum is preferably ammonium molybdate, and the compound of tungsten is preferably one or more of ammonium tungstate, ammonium metatungstate, ethyl ammonium metatungstate and nickel metatungstate. The nickel and cobalt compounds are preferably one or more of nickel nitrate, cobalt nitrate, nickel chloride, cobalt chloride, basic nickel carbonate and basic cobalt carbonate.

The hydrotreating catalyst is sulfided by conventional sulfiding methods prior to use to convert the oxidized form of the metal to the sulfided form. The hydrogenation active metal is changed from an oxidation state to a vulcanization state, which is beneficial to improving the activity and stability of the catalyst. The fats and oils contain substantially no sulfur, and therefore, in order to maintain the sulfided state of the catalyst during the hydrotreating process, it is necessary to ensure the sulfur content in the feed. The feed of the hydrotreating reaction unit contains a vulcanizing agent, wherein the vulcanizing agent is 100-5000mg/kg in terms of elemental sulfur, and is selected from H₂S、CS₂One or more of dimethyl disulfide, methyl sulfide, n-butyl sulfide, and thiophene.

According to the method provided by the invention, the reactor of the hydrotreating reaction unit is preferably a fixed bed reactor, the catalyst bed layer is divided into at least 3 catalyst bed layers, and the temperature of the catalyst bed layers can be controlled by injecting cold hydrogen between the catalyst bed layers. Through the matching of the diluent oil and the cold hydrogen, the stable operation of the hydrotreating reaction is controlled, and the temperature rise of the catalyst bed is controlled in a proper range.

The refined methyl ester is hydrotreated to generate C₈-C₂₄Alkane, water, CO₂And CH₄And the like. The gas phase product contains a large amount of hydrogen, CO and CO₂、H₂S、CH₄And the impurities can be purified by CO conversion, PAS pressure swing adsorption, steam reforming or other methods and then recycled. Generated C₈-C₂₄The dehydrated alkane enters a hydrogenation conversion reaction unit.

(3) Hydroconversion reaction unit

And (3) contacting the hydrogenation product obtained in the step (2) with a hydrogenation conversion catalyst in the presence of hydrogen, and carrying out selective cracking reaction under the hydrogenation conversion condition to obtain the hydrogenation conversion product. In the course of the reaction C₈-C₂₄By selective cracking and isomerization to give a mixture containing C₉-C₁₆The mixed components of the isoparaffin effectively improve the low-temperature performance of the product and adjust the distillation range distribution of the product in the unit.

The reaction conditions in the hydroconversion reaction unit are: the reaction temperature is 200-500 ℃, and preferably 300-380 ℃; hydrogen partial pressure is 1.0-10.0 MPa, preferably 3.0-8.0 MPa; the liquid hourly space velocity is 0.1-5.0 h^-1Preferably 0.5 to 3.0 hours^-1(ii) a The volume ratio of hydrogen to oil is 300-1200 Nm³/m³Preferably 400-800: 1.

The hydroconversion catalyst comprises a molecular sieve with a one-dimensional mesoporous structure, a heat-resistant inorganic oxide matrix and a hydrogenation metal component.

Based on the total amount of the hydro-conversion catalyst, the content of the one-dimensional mesoporous molecular sieve is 20-80 wt%, the content of the alumina is 15-75 wt%, the content of the hydrogenation metal is 0.2-5 wt% calculated by oxide, and the sum of the contents of the components is 100%. Preferably, the hydrogenation metal component is selected from one or more of cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, molybdenum and tungsten. The one-dimensional mesoporous molecular sieve is selected from one or more of ZSM-22, Nu-10, Thete-1, ISI-1, ZSM-23, SAPO-11, SAPO-31 and SAPO-41.

The metal active component of the hydroconversion catalyst is in a reduction state, the catalyst needs to be reduced before use and then used, and the reduction technology is a conventional technology.

The preferred hydroconversion catalyst of the invention has appropriate acidity and hydrogenation activity, can realize selective cracking, and can obtain high yield of C₉-C₁₆The isoparaffin can meet the aviation fuel product standards of freezing point, distillation range, viscosity and the like.

As the hydrocracking reaction occurs in the whole reaction process, a large amount of reaction heat is generated, and if the temperature rise of the reactor cannot be well controlled, more secondary cracking reactions are initiated, so that the yield of the target product is reduced. According to the method provided by the invention, the reactor of the hydroconversion reaction unit is preferably a fixed bed reactor, the catalyst bed layers are 2 or more than 2 catalyst bed layers, and the temperature of the catalyst bed layers can be controlled by injecting cold hydrogen.

(4) Fractionation of the product

And (4) separating and fractionating the oil generated by the hydrogenation conversion in the step (3) to obtain a kerosene component and a diesel oil component.

The invention provides a system for producing aviation fuel components from waste grease, which comprises the following components:

(1) the methyl esterification unit of the waste oil is provided with an alcoholysis reactor, a rectifying tower, a crude methyl ester glycerol settling separation zone and a crude methyl ester flash evaporation container, the waste oil and methanol carry out alcoholysis reaction in the alcoholysis reactor, and a mixed material after the alcoholysis reaction enters the rectifying tower to extract the methanol; the mixed material after methanol separation enters a crude methyl ester glycerol sedimentation separator, the upper part of the crude methyl ester glycerol sedimentation separator is provided with a crude methyl ester extraction line, the lower part of the crude methyl ester glycerol sedimentation separator is provided with a crude glycerol extraction line, the crude methyl ester extraction line is connected with an inlet of a crude methyl ester flash evaporation container, and the crude methyl ester flash evaporation container is provided with a fine methyl ester extraction line and a heavy oil extraction line;

(2) the system comprises a hydrotreating reaction unit, a hydrogenation reactor, a separation fractionation unit and a hydrogenation reaction unit, wherein the hydrotreating reaction unit is provided with a hydrotreating catalyst, a refined methyl ester extraction line from a waste oil methyl esterification unit is connected with an inlet of the hydrotreating reactor, an outlet of the hydrotreating reactor is connected with an inlet of the separation fractionation unit, the separation fractionation unit is provided with a gas-phase material outlet and a liquid-phase material outlet, the liquid-phase material outlet is connected with a liquid-phase material circulation line and a liquid-phase material extraction line, and the liquid-phase material circulation line is connected with an inlet of the hydrotreating reactor;

(3) the device comprises a hydrogenation conversion reaction unit, a hydrogenation conversion reactor and a hydrogenation conversion reaction unit, wherein the hydrogenation conversion reaction unit is provided with a hydrogenation conversion reactor, a hydrogenation conversion catalyst is filled in the hydrogenation conversion reactor, a liquid-phase material extraction line from a hydrotreating reaction unit is connected with an inlet of the hydrogenation conversion reactor, and an outlet of the hydrogenation conversion reactor is connected with a hydrogenation conversion reaction product extraction line;

(4) the device comprises a separation and fractionation unit, wherein a hydrogenation conversion reaction product extraction line of the hydrogenation conversion reaction unit is connected with an inlet of the separation and fractionation unit, and the separation and fractionation unit is provided with a gas phase material outlet, a kerosene component outlet and a diesel oil component outlet.

Compared with the prior art, the method effectively solves the problems of metal deposition, chloride ion corrosion and heat concentration of hydrogenation reaction in the hydrogenation process of the waste oil; the raw material adaptability is strong, and all waste grease raw materials can be used for producing the biological aviation fuel; can convert low-value methanol into a high-value glycerol product, realizes the effective utilization of waste oil resources, and improves the economic benefit of the process. The prepared aviation fuel does not contain sulfur, nitrogen, oxygen and aromatic hydrocarbon, and is a clean fuel; realizes the continuous and industrial production of the waste grease and has practical significance.

Drawings

FIG. 1 is a schematic flow diagram of a methyl esterification unit for waste oil and fat provided by the invention

FIG. 2 is a schematic flow diagram of a hydroprocessing reaction unit provided by the present invention

FIG. 3 is a schematic flow diagram of a hydroconversion reaction unit provided by the present invention

Detailed Description

The invention will be further described with reference to the accompanying drawings, but the invention is not limited thereto.

FIG. 1 is a schematic flow diagram of a methyl esterification unit for waste oil and fat provided by the present invention, as shown in FIG. 1, waste oil and fat 1, fresh methanol 2 and recycled methanol 5 are mixed, pressurized and heated, and then enter an alcoholysis reactor 100 for reaction; the mixed material 3 after alcoholysis reaction enters a rectifying tower 20, and the separated methanol 5 is recycled; the remaining mixed material 4, which mainly contains methyl esters and glycerol, enters a crude methyl ester glycerol settling separator 30, crude methyl esters 7 exit from the upper part of the separator 30 to enter a crude methyl ester flash vessel 40, and crude glycerol 6 exits from the lower part of the separator 30 to be further refined. The crude methyl ester 7 is flashed in a crude methyl ester flash vessel 40 to obtain refined methyl ester 8 and heavy grease 9, and the heavy grease 9 remaining after flashing can be used as fuel instead of heavy oil. And feeding the refined methyl ester 8 into a hydrotreating reaction unit.

FIG. 2 is a schematic flow diagram of a hydrotreating reaction unit provided by the invention, and as shown in FIG. 2, refined methyl ester 21 from a methyl esterification unit of waste oil and fat is mixed with a liquid phase material 30 circulating in a hydrotreating product, wherein the mass ratio of the refined methyl ester to the circulating liquid phase material is 1: 2-1: 6. And a vulcanizing agent is supplemented, and the mixture is mixed with fresh hydrogen 22 and circulating hydrogen 26, heated and then fed into a fixed bed reactor 200 filled with a hydrotreating catalyst. The reacted material 23 enters a high-pressure gas-liquid separator 50 after heat exchange and temperature reduction, the product is divided into gas-phase material 25, water 24 and liquid hydrocarbon 27, the gas-phase material 25 enters a gas treatment unit 60 to remove CO and CO₂、CH₄After impurities are removed, they are returned to the reactor inlet as recycle hydrogen 26. The resulting water 24 is removed from the bottom of the separator and the liquid hydrocarbons 27 are passed to a stripper 70 for further removal of water and H₂S, etc., the gas 28 exits the stripper 70 and a portion of the liquid feed 29 enters the hydroconversion reaction unit and another portion is mixed with the feedstock of the hydroprocessing reaction unit as recycle 30.

Fig. 3 is a schematic flow diagram of a hydroconversion reaction unit provided in the present invention, and as shown in fig. 3, a liquid feed 31 from the hydroprocessing reaction unit is mixed with fresh hydrogen 32 and recycle hydrogen 33, and then heated to enter a fixed bed reactor 300 containing a hydroconversion catalyst. The reacted material 34 enters a high-pressure gas-liquid separator 80 after heat exchange and temperature reduction, the obtained gas-phase material 33 is used as circulating hydrogen, and the obtained liquid-phase material 35 enters a fractionating tower 90 for separation to obtain liquefied gas 36, naphtha 37, kerosene component 38 and diesel oil component 39.

The following examples further illustrate the process of the present invention, but are not intended to limit the invention thereto.

In the following examples, the freeze point, flash point and total acid number of the kerosene components were measured according to the methods of GB/T2430, GB/T261 and GB/T12574, respectively. The mass yield of the kerosene component means the mass percentage of the prepared kerosene component to the mass of the waste oil raw oil.

Preparative example 1 preparation of hydrotreating catalyst

Weighing 500 g of pseudoboehmite (obtained from Changling catalyst factory), extruding into clover-shaped strips with the diameter of 1.6 mm of circumscribed circle by a strip extruding machine, and drying at 120 ℃ for 6 hours. Taking 300 g of the carrier S, and treating for 6 hours at the temperature of 600 ℃ by a one-step water vapor treatment method under the conditions that the volume ratio of air to water vapor is 1:0.6, the gas flow is 1.0 standard cubic meter/kilogram-hour, and the temperature is 600 ℃ to prepare the carrier S.

100 g of the carrier S was weighed, and was impregnated with 86 ml of an aqueous solution containing 5.8 g of ammonium paramolybdate, 29.7 g of nickel nitrate and 53.4 g of ammonium metatungstate for 2 hours, dried at 120 ℃ for 3 hours, and calcined at 450 ℃ for 4 hours, to obtain a hydroprocessing catalyst C. MoO in catalyst₃NiO and WO₃The contents by weight of (a) are 2.8%, 4.4% and 25.7%, respectively.

Preparation of catalyst for hydrotreatment of comparative example 1 preparation of catalyst for hydrotreatment

Weighing 500 g of pseudoboehmite (obtained from Changling catalyst factory), extruding into clover-shaped strips with the diameter of 1.6 mm of circumscribed circle by a strip extruding machine, drying at 120 ℃ for 6 hours, and roasting at 600 ℃ in air for 4 hours to obtain the carrier DS.

100 g of the carrier DS was weighed, and was impregnated with 86 ml of an aqueous solution containing 5.8 g of ammonium paramolybdate, 29.7 g of nickel nitrate and 53.4 g of ammonium metatungstate for 2 hours, dried at 120 ℃ for 3 hours, and calcined at 450 ℃ for 4 hours, to obtain a hydroprocessing catalyst DC. MoO in catalyst₃NiO and WO₃The contents by weight of (A) are respectively 2.6%, 4.5% and 25.8%.

Preparative example 2 preparation of hydroconversion catalyst

A catalyst was prepared according to the method of example 1 in CN102205250A, a ZSM-22 molecular sieve (supplied by Changling catalyst works, silica to alumina ratio 56) was uniformly mixed with pseudo-boehmite P1-1 and sesbania powder, an aqueous solution of nitric acid was added thereto, and the mixture was kneaded thoroughly, then clover-shaped strips having a diameter of 1.3 mm were extruded on a bar extruder, dried at 120 ℃ for 4 hours, and then calcined at 600 ℃ in air for 2 hours to obtain a carrier. The carrier is coated with a catalyst containing Pt (NH)₃)₄Cl₂The solution of (2) was saturated and then dried at 110 ℃ for 4 hours and calcined at 400 ℃ for 3 hours in an air atmosphere. Then, the obtained catalyst is reduced at the reduction temperature of 350 ℃, the reduction time is 4 hours, and the hydrogen pressure is 0.1 MPa. The reduced catalyst was a hydroconversion catalyst having a ZSM-22 content of 50.2 wt%, an alumina content of 49.0 wt%, and a Pt content of 0.8 wt%.

Example 1

(1) Methyl esterification unit for waste oil

Waste grease from catering industry is used as a raw material, and the quality indexes are as follows: density 0.91g cm^-3Oil with an acid value of 78mgKOH/g, sulfur of 35. mu.g/g, chlorine of 29. mu.g/g, mechanical impurities of 0.12 wt%, metal ion content of 11. mu.g/g, saponifiable matter content of 92.7 wt%, gum impurity of 6.3 wt%, and water content of 0.9 wt%. Mixing methanol and the raw materials according to the proportion of 0.3:0.7, heating and pressurizing, raising the temperature to 260 ℃, raising the pressure to 6.5MPa, then entering a reactor, staying for 1 hour, cooling and depressurizing after leaving the reactor, entering a methanol rectifying tower with the theoretical plate number of 30, and separating the methanol by controlling the conditions of the tower kettle temperature of 125 ℃, the tower top temperature of 67 ℃, the tower kettle pressure of 0.03MPa, the tower top pressure of 0.005MPa, the reflux ratio of 1 and the like. The water content of the methanol obtained by separation is 0.05 percent, and the methanol can be recycled. And (3) allowing the kettle liquid of the methanol rectifying tower to enter a crude methyl ester glycerol settling separator for settling and phase splitting, staying for 1 hour, pumping out the glycerol at the lower layer for refining, allowing the crude methyl ester at the upper layer to enter a crude methyl ester flash tower, and separating to obtain refined methyl ester and heavy oil, wherein the absolute pressure of the tower is 0.7 kPa. The content of fatty acid methyl ester in the refined methyl ester is 97 percent, the acid value is 1.7mgKOH/g oil, and the kinematic viscosity (40 ℃) is 4.2mm²S, sulfur content 4. mu.g/g, Cl content 1. mu.g/g, goldMetal ion content (as Na)⁺Gauge) 0.7. mu.g/g.

(2) Hydroprocessing reaction unit

Refined methyl ester obtained from the methyl esterification unit of the waste oil and the circulating liquid phase material H₂Mixing, adding a sulfur-containing compound with the sulfur content of 1000 mu g/g into the raw material, and contacting with a hydrotreating catalyst; the ratio of refined methyl ester to recycled liquid phase feed was 1:3 and the hydrotreating catalyst was the catalyst prepared in preparative example 1. The reaction conditions of the hydrotreatment are as follows: the pressure is 5.0MPa, the average temperature is 320 ℃, and the volume space velocity is 1.0h^-1The volume ratio of hydrogen to the reaction raw material was 1000: 1.

(3) Hydroconversion reaction unit

The mixture of the liquid phase stream from the hydrotreating reaction unit and hydrogen is contacted with a hydroconversion catalyst. The hydroconversion catalyst was the catalyst prepared in preparative example 2. The hydrotreating conditions include: the pressure is 5.0MPa, the average temperature is 330 ℃, and the volume space velocity is 1.0h^-1The volume ratio of hydrogen to oil is 500: 1.

(4) Product separation unit

The product after the hydroconversion reaction unit was fractionated to obtain 150-280 ℃ kerosene fraction, the properties of which are shown in Table 1.

Example 2

(1) Methyl esterification unit for waste oil

The waste grease from the rest of fried food is used as raw material, and the quality indexes are as follows: density 0.91g cm^-3Oil with an acid value of 5mgKOH/g, sulfur of 13. mu.g/g, chlorine of 7.8. mu.g/g, mechanical impurities of 0.22 wt%, metal ion content of 5.9. mu.g/g, saponifiable matter content of 95.3 wt%, gum impurity of 3.9 wt%, and water content of 0.7 wt%. Mixing methanol and the raw materials according to the ratio of 0.4:0.6, heating and pressurizing, raising the temperature to 280 ℃, raising the pressure to 8MPa, then entering a reactor, keeping the temperature for 1.5 hours, cooling and depressurizing after leaving the reactor, and entering a methanol rectifying tower with the theoretical plate number of 26. The methanol separation is carried out under the conditions of tower kettle temperature of 110 ℃, tower top temperature of 65 ℃, tower kettle pressure of 0.015MPa, tower top pressure of 0.002MPa, reflux ratio of 1.3 and the like. Obtained by separationThe water content of methanol is 0.046%, and the methanol can be recycled. And (3) allowing the kettle liquid of the methanol rectifying tower to enter a crude methyl ester glycerol settling separator for settling and phase splitting, staying for 1.5 hours, pumping out the glycerol at the lower layer for refining, allowing the crude methyl ester at the upper layer to enter a crude methyl ester flash tower, and separating to obtain refined methyl ester and heavy oil, wherein the absolute pressure of the tower is 0.5 kPa. Wherein the content of fatty acid methyl ester in the refined methyl ester is 98 percent, the acid value is 0.6mgKOH/g oil, and the kinematic viscosity (40 ℃) is 4.0mm²S, sulfur content 1. mu.g/g, Cl content none, metal ion content (as Na)⁺Gauge) 0.4. mu.g/g.

(2) Hydroprocessing reaction unit

Refined methyl ester obtained from the methyl esterification unit of the waste oil, circulating liquid phase material and H₂Mixing, adding a sulfur-containing compound with the sulfur content of 1000 mu g/g into the raw material, and contacting with a hydrotreating catalyst; the ratio of refined methyl ester to the recycled liquid phase feed oil was 1:2, and the hydrotreating catalyst was the catalyst prepared in preparative example 1. The reaction conditions of the hydrotreatment are as follows: the pressure is 5.0MPa, the average temperature is 330 ℃, and the volume space velocity is 2.0h^-1The volume ratio of hydrogen to the reaction raw material was 1000: 1.

(3) Hydroconversion reaction unit

The mixture of the liquid phase feed of the hydroprocessing reaction unit and hydrogen is contacted with a hydroconversion catalyst. The hydroconversion catalyst was the catalyst prepared in preparative example 2. The hydrotreating conditions include: the pressure is 5.0MPa, the average temperature is 340 ℃, and the volume space velocity is 1.5h^-1The volume ratio of hydrogen to oil is 500: 1.

(4) Product separation unit

The product of the hydroconversion reaction unit was fractionated to obtain 150-280 ℃ kerosene fraction having properties as shown in Table 1.

Example 3

(1) Methyl esterification of waste oil

The soybean acidified oil which is obtained by acidifying oil foot and soapstock which are generated by refining soybean oil is used as a raw material, and the quality indexes are as follows: density 0.90g cm^-3An acid value of 139mgKOH/g oil, sulfur content of 7. mu.g/g, chlorine content of 1.4. mu.g/g, mechanical impurities of 0.37 wt%, metal ion content of 255.6. mu.g/g, saponifiable matter content of 93.7 wt%5.1% of gum impurity and 1.1% of water. Mixing methanol and the raw materials according to the proportion of 0.27:0.73, heating and pressurizing, raising the temperature to 250 ℃, raising the pressure to 6MPa, then entering a reactor, keeping the temperature for 1 hour, cooling and depressurizing after leaving the reactor, and then entering a methanol rectifying tower with the theoretical plate number of 32. The methanol separation is carried out under the conditions of 105 ℃ of the tower kettle, 67 ℃ of the tower top, 0.010MPa of the tower kettle pressure, 0.001MPa of the tower top pressure, 0.9 of reflux ratio and the like. The water content of the methanol obtained by separation is 0.066 percent, and the methanol can be recycled. And (3) allowing the kettle liquid of the methanol rectifying tower to enter a crude methyl ester glycerol settling separator for settling and phase splitting, staying for 1.0 hour, pumping out the glycerol at the lower layer for refining, allowing the crude methyl ester at the upper layer to enter a crude methyl ester flash tower, and separating to obtain refined methyl ester and heavy oil, wherein the absolute pressure of the tower is 0.8 kPa. Wherein the content of fatty acid methyl ester in the refined methyl ester is 99 percent, the acid value is 1.9mgKOH/g oil, and the kinematic viscosity (40 ℃) is 4.1mm²S, no sulfur content and Cl content, metal ion content (as Na)⁺Gauge) 3.8. mu.g/g.

(2) Hydroprocessing reaction unit

Refined methyl ester obtained from the methyl esterification unit of the waste oil, circulating liquid phase material and H₂Mixing, adding a sulfur-containing compound with the sulfur content of 1000 mu g/g into the raw material, and contacting with a hydrotreating catalyst; the ratio of refined methyl ester to recycled liquid phase feed was 1:4 and the hydrotreating catalyst was the catalyst prepared in preparative example 1. The reaction conditions of the hydrotreatment are as follows: the pressure is 5.0MPa, the average temperature is 320 ℃, and the volume space velocity is 1.0h^-1The volume ratio of hydrogen to the reaction raw material was 1000: 1.

(3) Hydroconversion reaction unit

Contacting the liquid phase feed of the hydroprocessing reaction unit and the hydrogen gas mixture with a hydroconversion catalyst. The hydroconversion catalyst was the catalyst prepared in preparative example 2. The hydrotreating conditions include: the pressure is 5.0MPa, the average temperature is 330 ℃, and the volume space velocity is 1.0h^-1The volume ratio of hydrogen to oil is 500: 1.

(4) Product separation unit

The product after the hydroconversion reaction unit is fractionated to obtain 150-280 ℃ kerosene components, and the properties of the obtained kerosene components are shown in Table 1.

Example 4

(1) Methyl esterification unit for waste oil

The acidified oil derived from palm oil refining is used as a raw material, and the quality indexes are as follows: density 0.89g cm^-3Oil with an acid value of 151mgKOH/g, sulfur of 12. mu.g/g, chlorine of 23.4. mu.g/g, mechanical impurities of 0.41 wt%, metal ion content of 107.3. mu.g/g, saponifiable matter content of 94.1 wt%, gum impurity of 4.4 wt% and water of 1.4 wt%. Mixing methanol and the raw materials according to the ratio of 0.5:0.5, heating and pressurizing, raising the temperature to 270 ℃, raising the pressure to 7MPa, then entering a reactor, keeping the temperature for 1 hour, cooling and depressurizing after leaving the reactor, and then entering a methanol rectifying tower with the theoretical plate number of 36. The methanol separation is carried out under the conditions of the tower kettle temperature of 125 ℃, the tower top temperature of 69 ℃, the tower kettle pressure of 0.022MPa, the tower top pressure of 0.0015MPa, the reflux ratio of 1.1 and the like. The content of the separated methanol water is 0.035%, and the methanol water can be recycled. And (3) allowing the kettle liquid of the methanol rectifying tower to enter a crude methyl ester glycerol settling separator for settling and phase splitting, staying for 1.0 hour, pumping out the glycerol at the lower layer for refining, allowing the crude methyl ester at the upper layer to enter a crude methyl ester flash tower, and separating to obtain refined methyl ester and heavy oil, wherein the absolute pressure of the tower is 0.6 kPa. Wherein the content of fatty acid methyl ester in the refined methyl ester is 97.5 percent, the acid value is 1.4mgKOH/g oil, and the kinematic viscosity (40 ℃) is 4.0mm²S, no sulfur content and Cl content, metal ion content (as Na)⁺Gauge) 2.3. mu.g/g.

(2) Hydroprocessing reaction unit

Methyl ester obtained from the methyl esterification unit of the waste oil, circulating liquid phase material and H₂Mixing, adding a sulfur-containing compound with the sulfur content of 1000 mu g/g into the raw material, and contacting with a hydrotreating catalyst; the ratio of refined methyl ester to recycled liquid phase feed was 1:3 and the hydrotreating catalyst was the catalyst prepared in preparative example 1. The reaction conditions of the hydrotreatment are as follows: the pressure is 5.0MPa, the average temperature is 320 ℃, and the volume space velocity is 1.0h^-1The volume ratio of hydrogen to the reaction raw material was 1000: 1.

(3) Hydroconversion reaction unit

Subjecting the mixture of the liquid phase feed of the hydroprocessing reaction unit and hydrogen to hydroconversionAnd (4) contacting the catalyst. The hydroconversion catalyst was the catalyst prepared in preparative example 2. The hydrotreating conditions include: the pressure is 5.0MPa, the average temperature is 330 ℃, and the volume space velocity is 1.0h^-1The volume ratio of hydrogen to oil is 500: 1.

(4) Product separation unit

TABLE 1 part Properties of kerosene Components

As can be seen from the results in table 1, the kerosene component prepared by the method of the present invention satisfies the standards of synthetic paraffin kerosene derived from esters and fatty acids in ASTM D7566, and can be used as an aviation fuel component.

Comparative example 1 comparison of stability of hydrotreating catalyst

The refined methyl ester obtained in the methyl esterification unit of the waste oil and fat in the example 1, the recycled liquid phase material and H₂Mixing, adding a sulfur-containing compound with the sulfur content of 1000 mu g/g into the raw material, and contacting with a hydrotreating catalyst; the ratio of refined methyl ester to recycled liquid phase feed was 1:3 and the hydrotreating catalyst was catalyst C prepared in preparative example 1 and catalyst DC prepared in comparative preparative example 1. The reaction conditions of the hydrotreatment are as follows: the pressure is 5.0MPa, the average temperature is 320 ℃, and the volume space velocity is 2.0h^-1The volume ratio of hydrogen to the reaction raw material was 1000: 1. The hydrodeoxygenation activity data after a period of steady operation are shown in table 2.

The hydrodeoxygenation activity means (oxygen content of feedstock-oxygen content of liquid hydrocarbon product)/oxygen content of feedstock: < 100%

TABLE 2 relative hydrodeoxygenation Activity of hydroprocessing catalysts at different run times

It can be seen from the data in table 2 that, according to the method provided by the present invention, the carrier of the used hydrotreating catalyst is subjected to steam treatment without calcination, which can significantly stabilize the properties of the carrier and avoid the influence of water generated during the hydrotreating reaction on the hydrotreating catalyst.

Claims

1. A method of producing aviation fuel components from waste grease comprising the steps of:

(1) the waste oil methyl esterification unit is used for carrying out alcoholysis reaction on the waste oil and methanol after mixing, boosting and heating to obtain crude glycerol and crude methyl ester, and the crude methyl ester is subjected to flash evaporation to obtain refined methyl ester; the operating conditions of the methyl esterification unit of the waste oil and fat are as follows: carrying out alcoholysis reaction on the waste oil and methanol at the temperature of 180-320 ℃, under the reaction pressure of 4-10 MPa, wherein the mass ratio of the methanol to the oil is 0.2-1: 1, and the reaction time is 30-120 min;

(2) a hydrotreating reaction unit, which is used for contacting the refined methyl ester obtained in the step (1) with a hydrotreating catalyst in the presence of hydrogen, and carrying out a deoxidation reaction under the hydrotreating condition to obtain a hydrotreating product; the hydrotreating catalyst comprises a carrier of alumina and a hydrogenation active component loaded on the carrier, wherein the hydrogenation active component comprises at least one metal component selected from VIII group and at least one metal component selected from VIB group, and the alumina carrier comprises a step of water vapor treatment in the preparation process;

2. A method according to claim 1, wherein the waste oil or fat is an inedible waste oil or fat produced in animal or vegetable oil or fat processing and consumption.

3. The method of claim 1, wherein the waste oil methyl esterification unit is operated under the following conditions: carrying out alcoholysis reaction on the waste oil and methanol at the temperature of 220-300 ℃, under the reaction pressure of 5-8 MPa, wherein the mass ratio of methanol to oil is 0.3-0.7: 1; the reaction time is 60-90 min.

4. The method according to claim 1, wherein in the methyl esterification unit of the waste oil and fat in the step (1), the mixed material after alcoholysis reaction enters a rectifying tower, and methanol is extracted by adopting a rectifying method, wherein the rectifying tower is a packed tower or a plate tower.

5. The method according to claim 1 or 4, characterized in that a crude methyl ester glycerol settling separator and a crude methyl ester flash vessel are arranged in the methyl esterification unit of the waste oil and fat in the step (1), methanol is separated from the mixed material after alcoholysis reaction and then the mixed material enters the crude methyl ester glycerol settling separator, and the separator is continuously operated under the operating conditions that: keeping the temperature of the materials at 40-80 ℃ and the retention time for 0.5-3 h; after the settling is finished, the crude methyl ester leaves from the upper part of the separator and enters a crude methyl ester flash evaporation container, and the crude glycerin leaves from the lower part of the separator; and carrying out flash evaporation treatment on the crude methyl ester to obtain refined methyl ester, wherein a flash evaporation container of the crude methyl ester is a flash evaporation tank or a flash evaporation tower.

6. The process according to claim 5, wherein in the methyl esterification unit of waste fats & oils of step (1), the separator is continuously operated under the operating conditions of: keeping the temperature of the material at 50-70 ℃; the retention time is 1-2 h.

7. The process of claim 5, wherein the crude methyl ester flash vessel is a flash drum or a flash column, the flash column operating at conditions of: the temperature is 220-350 ℃, and the pressure is 2-0.3 kPa.

8. A process according to claim 1 or 5 wherein the essential methyl ester has a fatty acid methyl ester content in excess of 95%, a sulphur content of not more than 10 μ g/g, a chlorine content of not more than 1 μ g/g and a sum of the metal ion contents of not more than 2 μ g/g.

9. The process of claim 1, wherein the hydroprocessing reaction unit has reaction conditions of: the reaction temperature is 200-400 ℃, the hydrogen partial pressure is 1.0-10.0 MPa, and the liquid hourly space velocity is 0.5-10.0 h^-1Hydrogen to oil volume ratio of 500 to 1500Nm³/m³。

10. The method according to claim 1, wherein the liquid phase material in the hydrotreating product is partially recycled to the inlet of the hydrotreating reaction unit, and the mass ratio of the refined methyl ester to the recycled liquid phase material is 1: 2-1: 6.

11. The method of claim 1, wherein the hydrotreating catalyst preparation step comprises:

(1) mixing, molding and drying hydrated alumina;

(2) carrying out water vapor treatment to obtain a carrier;

12. The method of claim 11 wherein the hydrated alumina is pseudoboehmite.

13. The method according to claim 1 or 11, wherein the conditions of the water vapor treatment step include: the temperature is 450-750 ℃, the time is 4-8 hours, and the steam flow is 0.5-5.0 standard cubic meter/kilogram carrier per hour.

14. The method of claim 11, wherein the firing conditions in step (3) are: the temperature is 400-650 ℃, and the time is 2-6 hours.

15. The method according to claim 1 or 11, wherein in the hydrogenation active component of the hydrotreating catalyst, the group VIII metal component is cobalt and/or nickel, the group VIB metal component is molybdenum and/or tungsten, and the content of the group VIII metal component is 1 to 10 wt% and the content of the group VIB metal component is 10 to 45 wt% in terms of oxide and based on the catalyst.

16. The process of claim 1, wherein the reaction conditions in the hydroconversion reaction unit are: the reaction temperature is 200-500 ℃, the hydrogen partial pressure is 1.0-10.0 Mpa, and the liquid hourly space velocity is 0.5-5.0 h^-1Hydrogen to oil volume ratio of 300-1200 Nm³/m³。

17. The process of claim 1 wherein the hydroconversion catalyst comprises a molecular sieve having a one-dimensional mesoporous structure, a refractory inorganic oxide matrix, and a hydrogenation metal component.

18. The process according to claim 17, wherein the content of the one-dimensional mesoporous molecular sieve is 20 to 80% by weight, the content of the alumina is 15 to 75% by weight, the content of the hydrogenation metal component is 0.2 to 5% by weight in terms of oxide, and the sum of the contents of the above components is 100% based on the total amount of the hydroconversion catalyst.

19. The process of claim 17 or 18, wherein the hydrogenation metal component is selected from one or more of cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, molybdenum and tungsten.

20. The method of claim 17 or 18, wherein the one-dimensional mesoporous molecular sieve is selected from one or more of ZSM-22, Nu-10, Thete-1, ISI-1, ZSM-23, SAPO-11, SAPO-31, SAPO-41.

21. A system for producing aviation fuel components from waste grease, comprising: