CN107841340B - A method for preparing bio-aviation hydrocarbon fuels by thermochemical conversion of triglycerides - Google Patents

Abstract

A method for preparing bio-aviation hydrocarbon fuels by thermochemical conversion of triglycerides, catalytic cracking: adding triglycerides and a basic catalyst into a cracking reactor for catalytic cracking to obtain cracked oil; atmospheric distillation: the obtained cracked oil Put it into a three-necked flask, carry out atmospheric distillation, and collect fractions; aromatization: add the obtained fractions and aromatization catalyst into a high-pressure reactor, start stirring, and heat the reaction. After the reaction is completed, the catalyst is removed by centrifugation to obtain alkane and Aviation hydrocarbon fuel components with aromatics as the main component; hydrogenation: Add aviation hydrocarbon fuel components and hydrogenation catalysts to the high-pressure reactor, feed hydrogen, start stirring, and heat the reaction; after the reaction, filter out Catalyst to obtain a liquid mixture with alkanes, aromatic hydrocarbons and cycloalkanes as main components, which is bio-aviation hydrocarbon fuel. The hydrocarbon fuel oil produced by the invention is a mixture of alkanes, aromatic hydrocarbons and cycloalkanes, which has the same components and similar properties as aviation fuel oil.

Description

A method for preparing bio-aviation hydrocarbon fuels by thermochemical conversion of triglycerides

technical field

The invention belongs to the field of high-value utilization of biomass energy, and in particular relates to a method for preparing bio-aviation hydrocarbon fuel by thermochemical conversion of triglyceride.

Background technique

At present, my country's aviation fuel comes from petrochemical refining, but the yield components of aviation fuel only account for about 10% of the total crude oil. Aviation fuel is an important guarantee for the development of my country's civil aviation. Under the dual pressure of depletion of petroleum resources and carbon emission reduction, the development of alternative bio-aviation fuels using biomass as raw material has attracted widespread attention. Triglycerides, as the main components of bio-oils (vegetable oils and animal fats), have a chemical structure closer to that of petroleum than other biomass. The most common conversion method of triglycerides is transesterification to produce biodiesel for vehicles. The main component of biodiesel is fatty acid methyl ester, which is quite different from petrochemical fuel components. It has poor low-temperature fluidity, high oxygen content, and low calorific value, which is far from meeting the use standards of aviation fuel.

Catalytic cracking of bio-oils is another important route to produce renewable liquid fuels. The main catalysts used are alumina, molecular sieves and basic catalysts. Among them, the fuel oil prepared with alumina and molecular sieve as a catalyst has a high acid value and poor low-temperature fluidity. Moreover, the pyrolysis products using molecular sieves as catalysts are mainly C6-C9 aromatic hydrocarbons in the range of gasoline components or C12-C18 hydrocarbons in the range of diesel components, which cannot meet the requirements of aviation fuel molecular weight distribution in C8-C15. Liquid fuels prepared with basic oxides as catalysts are mainly composed of linear alkanes with a molecular weight distribution of C8-C19. Aviation fuel is a mixture of alkanes, aromatic hydrocarbons and cycloalkanes as the main components. A single molecular structure cannot To meet the demand of aviation fuel, further regulation of the molecular weight and molecular structure of pyrolysis fuel oil is required. In addition, although the acid value of fuel oil produced by alkali-catalyzed cracking is relatively low, it is still necessary to further reduce the acid value for the use of aviation fuel.

Contents of the invention

Technical problem to be solved: In order to solve the problem of partial fatty acids and single molecular structure in the existing pyrolysis oil, the present invention provides a method for preparing aviation hydrocarbon fuel by thermochemical conversion of triglyceride. The hydrocarbon fuel produced is a mixture of alkanes, aromatic hydrocarbons and cycloalkanes, which have the same components and similar properties as aviation fuel.

Technical solution: a method for preparing bio-aviation hydrocarbon fuel by thermochemical conversion of triglycerides, comprising the following steps: the first step, catalytic cracking: adding triglycerides and a basic catalyst into a cracking reactor, the basic catalyst The added amount of triglyceride accounts for 5-20wt.% of triglyceride; Under the conditions of reaction kettle temperature 350°C-450°C and rectification column temperature 260°C-320°C, catalytic cracking is carried out to obtain pyrolysis oil; the second step, usually Pressure distillation: Add the obtained cracked oil into a three-necked flask, carry out atmospheric distillation, and collect fractions at 90°C to 270°C; the third step, aromatization: add the fractions obtained in the previous step and the aromatization catalyst into a high-pressure reaction kettle , the addition amount of the aromatization catalyst is 5 to 15wt.% of the fraction; start stirring, raise the temperature of the reactor to 300°C to 350°C, and the reaction time is 2 to 8h. After the reaction is completed, the catalyst is removed by centrifugation to obtain Liquid fuel with alkanes and aromatics as the main components; the fourth step, hydrogenation: add the liquid fuel and hydrogenation catalyst obtained in the previous step into the high-pressure reactor, and the addition of the hydrogenation catalyst accounts for 1-2% of the fuel oil. 10wt.%, feed 4-9MPa hydrogen, start stirring, raise the temperature of the reactor to 150°C-250°C, and the reaction time is 2-8h; after the reaction, filter out the catalyst to obtain alkanes, aromatic hydrocarbons and naphthenes The main component is a liquid mixture, which is bio-aviation hydrocarbon fuel.

The above-mentioned triglyceride is any one of soybean oil, rubber seed oil, acidified oil or waste oil.

The above-mentioned basic catalyst is an alkali metal, an alkaline earth metal oxide or an alkaline earth metal hydroxide.

Above-mentioned basic catalyst is any one in sodium carbonate, sodium hydroxide, potassium hydroxide, calcium oxide.

The mass fraction of the above-mentioned basic catalyst accounts for 10wt.% of the triglyceride, the temperature of the reaction kettle is 350°C-420°C, and the temperature of the rectification column is 280°C-300°C.

The aromatization catalyst mentioned above is any one of HZSM-5 and its modified molecular sieve catalysts.

The mass fraction of the above-mentioned aromatization catalyst is 5-15wt.% of the cracked oil fraction, the reaction temperature is 350° C., and the reaction time is 6 hours.

The above-mentioned hydrogenation catalyst is any one of Raney nickel, Pd/C, Pt/C and Rh/C.

The hydrogen initial pressure in the above hydrogenation reaction is 6MPa, the reaction temperature is 200°C, and the reaction time is 6h.

Beneficial effects: the invention provides a method for preparing bio-aviation hydrocarbon fuel by thermochemical conversion of triglycerides, using a catalyst in the cracking process to reduce the acid value of the cracked oil. Through atmospheric distillation, the components with carbon chain lengths of C8-C15 in the pyrolysis oil are extracted as aviation components. And through the aromatization process, the aromatization of olefins and the deacidification of residual carboxylic acids are realized, the existence of unstable components in cracked oil is reduced, the acid value is reduced, and the content of aromatic hydrocarbons is increased. The hydrogenation reaction converts part of the aromatic hydrocarbons into naphthenes, and obtains a mixture with alkanes, aromatic hydrocarbons and naphthenes as the main components. Its composition is consistent with that of aviation fuel, and its properties are similar. It provides an effective way for high-value utilization of bio-oil and conversion into bio-aviation hydrocarbon fuel.

Description of drawings

Fig. 1 is the component change figure in the thermochemical conversion process of embodiment 1;

Fig. 2 is embodiment 1, embodiment 2, the carbon chain length distribution diagram of the pyrolysis oil of embodiment 3 and embodiment 4.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the specific content of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

A method for preparing bio-aviation hydrocarbon fuel by thermochemical conversion of triglycerides, comprising the following steps:

In the first step, triglyceride and basic catalyst are added to the cracking reaction kettle, the addition of the basic catalyst accounts for 5-20wt.% of the triglyceride, the temperature of the reaction kettle is controlled at 350°C-450°C, and the rectification column At a temperature of 260°C to 320°C, carry out alkali-catalyzed cracking; the alkali catalyst is an alkali metal or alkaline earth metal oxide or hydroxide, which can be any one of sodium carbonate, sodium hydroxide, potassium hydroxide, and calcium oxide species, preferably sodium carbonate.

In the second step, the obtained pyrolysis oil is added into a three-necked flask, subjected to normal pressure distillation, and fractions at 90° C. to 270° C. are collected. Normal pressure mentioned in the text refers to one standard atmosphere.

In the third step, the fraction obtained in the previous step and the aromatization catalyst are added to the autoclave, the addition of the aromatization catalyst is 5 to 15wt.% of the fraction, the stirring is started, and the temperature of the reactor is raised to 300 °C to 350 °C, the reaction time is 2 to 8 hours, and after the reaction is completed, the catalyst is removed by centrifugation to obtain liquid fuel oil with alkanes and aromatics as main components.

The fourth step is to add the liquid fuel material and the hydrogenation catalyst obtained in the previous step into the high-pressure reactor. The addition of the hydrogenation catalyst accounts for 1-10wt.% of the fuel oil, and 4-9MPa hydrogen is introduced. The temperature of the reactor is Raise the temperature to 150°C-250°C, react for 2-8 hours, filter out the catalyst, and obtain bio-aviation hydrocarbon fuel.

Example 1

Add 1500g soybean oil and 10wt.% sodium carbonate into the pyrolysis reaction kettle, start stirring, and the temperature of the rectification column rises to 280°C-300°C. When the temperature of the reaction kettle rises to 350°C, condensed liquid appears, and the temperature is gradually raised to 450°C. Keep until no lysis liquid flows out. Atmospheric distillation is carried out on the cracked liquid, and fractions at 90°C to 270°C are collected. Take 80g fraction and 5wt.% HZSM-5 (Si/Al=27) catalyst in a high-pressure reactor, start stirring, the reactor is heated to 350°C, react for 6h, and remove the catalyst by centrifugation. Take 40g of the product from the previous step and 5wt.% Pd/C catalyst in a high-pressure reactor, feed hydrogen gas at 6MPa, start stirring, heat the reactor to 200°C, and react for 6 hours to obtain a mixture containing alkanes, aromatic hydrocarbons and naphthenes , which is bio-aviation fuel.

Example 2

Add 1500g waste oil and 5wt.% sodium carbonate into the pyrolysis reaction kettle, start stirring, and the temperature of the rectification column rises to 280°C-300°C. When the temperature of the reaction kettle rises to 350°C, condensed liquid appears, and the temperature is gradually raised to 450°C. Keep until no lysis liquid flows out. Atmospheric distillation is carried out on the cracked liquid, and fractions at 90°C to 270°C are collected. Take 80g fraction and 5wt.% HZSM-5 (Si/Al=27) catalyst in a high-pressure reactor, start stirring, the reactor is heated to 350°C, react for 8h, and remove the catalyst by centrifugation. Take 40g of the product from the previous step and 5wt.% Pd/C catalyst in a high-pressure reactor, feed hydrogen gas at 6MPa, start stirring, heat the reactor to 200°C, and react for 6 hours to obtain a mixture containing alkanes, aromatic hydrocarbons and naphthenes , which is bio-aviation fuel.

Example 3

Add 1500g soybean oil and 5wt.% sodium carbonate into the pyrolysis reactor, start stirring, and the temperature of the rectification column rises to 260°C-280°C. When the reactor heats up to 350°C, condensed liquid appears, and gradually heats up to 420°C. Keep until no lysis liquid flows out. Atmospheric distillation is carried out on the cracked liquid, and fractions at 90°C to 270°C are collected. Take 80g fraction and 5wt.% HZSM-5 (Si/Al=27) catalyst in a high-pressure reactor, start stirring, the reactor is heated to 350°C, react for 2h, and remove the catalyst by centrifugation. Take 40g of the product from the previous step and 5wt.% Pd/C catalyst in a high-pressure reactor, feed hydrogen gas at 4MPa, start stirring, heat the reactor to 200°C, and react for 4 hours to obtain a mixture containing alkanes, aromatic hydrocarbons and naphthenes , which is bio-aviation fuel.

Example 4

Add 1500g soybean oil and 10wt.% sodium carbonate into the pyrolysis reaction kettle, start stirring, and the temperature of the rectification column rises to 260°C-280°C. When the temperature of the reaction kettle rises to 350°C, condensed liquid appears, and the temperature is gradually raised to 420°C. Keep until no lysis liquid flows out. Atmospheric distillation is carried out on the cracked liquid, and fractions at 90°C to 270°C are collected. Take 80g fraction and 15wt.% HZSM-5 (Si/Al=27) catalyst in a high-pressure reactor, start stirring, the reactor is heated to 300°C, react for 4h, and remove the catalyst by centrifugation. Take 40g of the product from the previous step and 10wt.% Pd/C catalyst in a high-pressure reactor, feed hydrogen gas at 9MPa, start stirring, heat the reactor to 200°C, and react for 6h to obtain a mixture containing alkanes, aromatic hydrocarbons and naphthenes , which is bio-aviation fuel.

Example 5

Add 1500g soybean oil and 15wt.% sodium carbonate into the pyrolysis reaction kettle, start stirring, and the temperature of the rectification column rises to 300°C-320°C. When the temperature of the reaction kettle rises to 350°C, condensed liquid appears, and the temperature is gradually raised to 420°C. Keep until no lysis liquid flows out. Atmospheric distillation is carried out on the cracked liquid, and fractions at 90°C to 270°C are collected. Take 80g fraction and 10wt.% HZSM-5 (Si/Al=27) catalyst in a high-pressure reactor, start stirring, the reactor is heated to 320°C, react for 6h, and remove the catalyst by centrifugation. Take 40g of the product from the previous step and 1wt.% Pd/C catalyst in a high-pressure reactor, feed hydrogen gas at 9MPa, start stirring, heat the reactor to 200°C, and react for 8 hours to obtain a mixture containing alkanes, aromatic hydrocarbons and naphthenes , which is bio-aviation fuel.

Example 6

Add 1500g soybean oil and 5wt.% sodium carbonate into the pyrolysis reaction kettle, start stirring, and the temperature of the rectification column rises to 300°C-320°C. When the temperature of the reaction kettle rises to 350°C, condensed liquid appears, and the temperature is gradually raised to 450°C. Keep until no lysis liquid flows out. Atmospheric distillation is carried out on the cracked liquid, and fractions at 90°C to 270°C are collected. Take 80g fraction and 5wt.% HZSM-5 (Si/Al=27) catalyst in a high-pressure reactor, start stirring, the reactor is heated to 350°C, react for 4h, and remove the catalyst by centrifugation. Take 40g of the product from the previous step and 5wt.% Pd/C catalyst in a high-pressure reactor, feed hydrogen gas at 6MPa, start stirring, heat the reactor to 200°C, and react for 2 hours to obtain a mixture containing alkanes, aromatic hydrocarbons and naphthenes , which is bio-aviation fuel.

Example 7

Add 1500g soybean oil and 5wt.% calcium oxide into the pyrolysis reaction kettle, start stirring, and the temperature of the rectification column rises to 280°C-300°C. When the temperature of the reaction kettle rises to 350°C, condensed liquid appears, and the temperature is gradually raised to 450°C. Keep until no lysis liquid flows out. Atmospheric distillation is carried out on the cracked liquid, and fractions at 90°C to 270°C are collected. Take 80g fraction and 5wt.% HZSM-5 (Si/Al=50) catalyst in a high-pressure reactor, start stirring, the reactor is heated to 350°C, react for 6h, and remove the catalyst by centrifugation. Take 40g of the product from the previous step and 5wt.% Pd/C catalyst in a high-pressure reactor, feed hydrogen gas at 6MPa, start stirring, heat the reactor to 200°C, and react for 6 hours to obtain a mixture containing alkanes, aromatic hydrocarbons and naphthenes , which is bio-aviation fuel.

Example 8

Add 1500g soybean oil and 5wt.% sodium carbonate into the pyrolysis reaction kettle, start stirring, and the temperature of the rectification column rises to 280°C-300°C. When the temperature of the reaction kettle rises to 350°C, condensed liquid appears, and the temperature is gradually raised to 450°C. Keep until no lysis liquid flows out. Atmospheric distillation is carried out on the cracked liquid, and fractions at 90°C to 270°C are collected. Take 80g fraction and 5wt.% HZSM-5 (Si/Al=27) catalyst in a high-pressure reactor, start stirring, the reactor is heated to 350°C, react for 6h, and remove the catalyst by centrifugation. Take 40g of the product from the previous step and 10wt.% Raney nickel catalyst in a high-pressure reactor, feed hydrogen gas at 9MPa, start stirring, heat the reactor to 200°C, and react for 6 hours to obtain a mixture containing alkanes, aromatic hydrocarbons and cycloalkanes , which is bio-aviation fuel.

Example 9

Add 1500g soybean oil and 20wt.% sodium carbonate into the pyrolysis reaction kettle, start stirring, and the temperature of the rectification column rises to 280°C-300°C. When the temperature of the reaction kettle rises to 350°C, condensed liquid appears, and the temperature is gradually raised to 450°C. Keep until no lysis liquid flows out. Atmospheric distillation is carried out on the cracked liquid, and fractions at 90°C to 270°C are collected. Take 80g fraction and 5wt.% HZSM-5 (Si/Al=27) catalyst in a high-pressure reactor, start stirring, the reactor is heated to 320°C, react for 6h, and remove the catalyst by centrifugation. Take 40g of the product from the previous step and 5wt.% Raney nickel catalyst in a high-pressure reactor, feed hydrogen gas at 9MPa, start stirring, heat the reactor to 150°C, and react for 6 hours to obtain a mixture containing alkanes, aromatic hydrocarbons and cycloalkanes , which is bio-aviation fuel.

The result of alkali-catalyzed cracking in the embodiment of table 1

Component changes in the reaction process in the embodiment 1 of table 2

Component changes in the reaction process in the embodiment 2 of table 3

The properties of fuel oil in Table 4 Example 1 are compared with the properties of aviation fuel in the national standard

aRefer to GB/T 6537-2006.

Claims (1)

1. a kind of method that triglycerides thermochemical study prepares biological aviation hydrocarbon fuel, it is characterised in that including following step It is rapid: the sodium carbonate of 1500 g soybean oils and 10 wt.% being added in cracking reaction kettle, stirring is opened, rectifying column temperature is warming up to 280 DEG C ~ 300 DEG C, when reaction kettle is warming up to 350 DEG C, there is condensed fluid, be gradually heated to 450 DEG C, keeps to no cracking Liquid outflow；Air-distillation is carried out to cracking liquid, collects 90 DEG C ~ 270 DEG C fractions；Take 80 g fractions and 5 wt.% Si/Al =27 HZSM-5 catalyst opens stirring in autoclave, and reaction kettle is warming up to 350 DEG C, reacts 6 h, is centrifuged off Catalyst；It takes 40 g previous step products and 5 wt.% Pd/C catalyst in autoclave, is passed through 6 MPa of hydrogen, open Stirring, reaction kettle are warming up to 200 DEG C, react 6 h, the mixture containing alkane, aromatic hydrocarbon and cycloalkane can be obtained, as Biological Aviation Fuel.

Images