Pyrolysis catalyst as well as preparation method and application thereof

Abstract

The invention discloses a pyrolysis catalyst as well as a preparation method and application thereof. The pyrolysis catalyst is prepared from the following raw materials: 10 to 30 percent of transition metal salt, 1 to 5 percent of clay mineral substance, 20 to 40 percent of alkaloid, 15 to 35 percent of alcohol substance and 5 to 10 percent of urea. In the oil shale pyrolysis process of the prepared catalyst, on one hand, formed positive carbon ions can interact with a neutral molecule or positive carbon ions to generate a series of chemical reactions, and kerogen is promoted to be degraded into hydrocarbon or pyrolytic hydrocarbon to be further converted; and on the other hand, the oil base material in the shale and the free radicals of the biomass productivity can interact, the oxygen distribution in the biomass pyrolysis volatile matter is influenced, the generation amount of the oxygen component in the liquid product is reduced, and the shale oil quality can be improved. The two components have a synergistic effect in the catalytic oil shale pyrolysis process, so that the pyrolysis efficiency of the oil shale is improved, the distribution of oil shale pyrolysis products is improved, more light products are produced, and the quality of the pyrolysis product shale oil is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic pyrolysis of oil shale, and particularly to a pyrolysis catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Oil shale is a solid combustible organic matter sedimentary rock with high ash content. Through low-temperature retorting, oil shale oil can be obtained, with an oil content greater than 3.5% and a calorific value generally not less than 4.18 MJ / kg, belonging to unconventional oil and gas resources. Oil shale is considered an important energy source to replace petroleum and natural gas in the future. Since the kerogen in oil shale is completely solid in its natural state and cannot be directly exploited, only through pyrolysis can liquid shale oil be generated from the conversion of kerogen. However, conventional pyrolysis technologies have many deficiencies, such as large limitations, a large amount of land occupation for open-pit mining and serious damage to the ecological environment, high energy consumption, high cost, and low efficiency. Therefore, how to efficiently and environmentally utilize oil shale resources has become an urgent problem to be solved currently.

[0003] As a substance that can regulate the chemical reaction process and change the energy required for a chemical reaction, studying its role in oil shale has profound significance and influence on the decomposition of oil shale and the yield distribution of pyrolysis products, which is conducive to promoting the development and improvement of shale oil extraction technology.

[0004] Currently, pyrolysis catalysts mainly include metal salts, clay minerals, and molecular sieve catalysts. Among them, transition metal salt catalysts are the most commonly used oil shale catalysts. Transition metals have empty d orbitals, which can easily form complexes and have strong bond-breaking ability. Moreover, such catalysts have the advantages of simple preparation and high activity. Research has found that metal oxides and chlorides such as Fe, Ca, Zn, and Ni can improve the pyrolysis efficiency of oil shale, generate hydrogen free radicals, and lighten the shale oil. Through experiments, it has been found that metal salts can also catalyze the aromatization of aliphatic hydrocarbons to form aromatic hydrocarbons and promote the secondary pyrolysis of shale oil, thereby reducing the activation energy of the three stages of oil shale pyrolysis to varying degrees. However, the catalytic ability of a single transition metal salt catalyst is very limited, and how to improve the catalytic effect of the catalyst is the current research focus.

[0005] CN101962559A discloses a method for producing light fuel oil from oil shale - like ores. After the oil shale - like ores are crushed and screened, they are heated and pyrolyzed under the condition of adding a catalyst to produce light fuel oil. Among them, the total amount of the added catalyst is 0.8 - 2% of the mass of the oil shale - like ores, and 30 - 70% of it is added to the oil shale - like ore raw materials before heating and pyrolysis, and the remaining catalyst is added to the oil shale - like ore raw materials during the pyrolysis process. However, the catalytic activity of the catalyst for the oil shale prepared by this method is low, a large amount of catalyst is required during the application process, the cost is high, and it is difficult to be industrially applied. CN103878031A discloses a preparation method and a use method of a catalyst for oil shale pyrolysis. This catalyst can improve the pyrolysis efficiency of oil shale, improve the distribution of oil shale pyrolysis products, produce more light products, and gasoline and diesel components can be separated by rectification. The present invention combines catalytic pyrolysis with microwave heating, which can improve the energy utilization efficiency, improve the composition and process properties of liquid fuels, and reduce the subsequent processing difficulty. However, this catalyst has a certain promoting effect on the production of fuel oil by oil shale pyrolysis, but its catalytic ability is very limited and the pyrolysis efficiency is low. And the preparation of the pyrolysis catalyst is expensive and it is difficult to achieve industrialization. Summary of the Invention

[0006] The object of the present invention is to overcome the problems existing in the prior art such as low pyrolysis efficiency and high price, and to provide a pyrolysis catalyst, its preparation method and application. This pyrolysis catalyst can improve the pyrolysis efficiency of oil shale, improve the distribution of oil shale pyrolysis products, produce more light products, improve the quality of the pyrolysis product shale oil, and at the same time can reduce the pyrolysis temperature of oil shale and improve the energy utilization efficiency.

[0007] To achieve the above object, in the first aspect of the present invention, a pyrolysis catalyst is provided. The raw materials of the pyrolysis catalyst include: 10% - 30% of transition metal salts, 1% - 5% of clay minerals, 20% - 40% of alkaloids, 15% - 35% of alcohol substances, and 5% - 10% of urea.

[0008] In the second aspect of the present invention, a preparation method of a pyrolysis catalyst is provided. The preparation method includes the following steps:

[0009] Place the raw materials of the pyrolysis catalyst described in the first aspect above in a three - necked flask, heat and react to obtain an intermediate;

[0010] First perform a first treatment on the intermediate at a first temperature, and then perform a second treatment at a second temperature to obtain the pyrolysis catalyst.

[0011] In the third aspect of the present invention, the application of the pyrolysis catalyst described in the first aspect above or the pyrolysis catalyst prepared in the second aspect in the pyrolysis of oil shale or medium - low maturity shale oil is provided.

[0012] The fourth aspect of the present invention provides a method for pyrolyzing oil shale, and the method includes the following steps:

[0013] Mix the oil shale with the pyrolysis catalyst described in the first aspect of the foregoing claims or the pyrolysis catalyst prepared in the second aspect, and then perform catalytic pyrolysis. After separation, shale oil and pyrolysis gas are obtained.

[0014] Through the above technical solutions, the beneficial technical effects achieved by the present invention are as follows:

[0015] (1) During the pyrolysis of oil shale by the catalyst prepared in the present invention, on the one hand, transition metal ions and clay minerals have the properties of solid acids on the surface of biomass. The Lewis acid on the catalyst can initiate the formation of carbocations from alkanes, and olefins and aromatics can generate carbocations by the Bronsted acid (proton acid) on the catalyst. The carbocations can undergo β-scission to form hydrocarbons with small molecular weights. That is, the formed carbocations can interact with a neutral molecule or between carbocations to produce a series of chemical reactions, promoting the degradation of kerogen into hydrocarbons or the further conversion of pyrolysis hydrocarbons. On the other hand, the free radicals produced by kerogen and biomass in the shale will interact with each other. This interaction affects the oxygen distribution in the pyrolysis volatiles of biomass, promotes the generation of CO2 and CO, and reduces the generation amount of oxygen components in the liquid products, which helps to improve the quality of shale oil. The two act synergistically during the catalytic pyrolysis of oil shale, which greatly improves the catalytic pyrolysis effect of shale.

[0016] (2) The catalyst prepared in the present invention is prepared by the combustion method, which is equivalent to the hydrothermal method. The operation process is simple, the preparation method is simple, and the yield is much higher than that obtained by the hydrothermal method. At the same time, the catalyst prepared by the combustion method has a small particle size, between a few nanometers and more than a dozen nanometers, which is nanoscale. Metal doping can change the surface properties of the catalyst, enhance the active sites of the catalyst, and improve its catalytic activity and selectivity. Therefore, the catalyst prepared by the method of the present invention has very high catalytic activity in the pyrolysis of oil shale, can not only greatly reduce the activation energy in the pyrolysis process of oil shale, but also helps to improve the quality of shale oil. At the same time, the catalyst is inexpensive and has a very small particle size, which is easy to inject into the formation, facilitating industrialization.

[0017] (3) The catalyst of the present invention can efficiently reduce the activation energy of the oil shale pyrolysis reaction, reduce energy consumption, and the catalyst can also improve the pyrolysis efficiency of oil shale, improve the distribution of the pyrolysis products of oil shale, improve the quality of the pyrolysis product shale oil, produce more light products, thereby improving the quality of shale oil in the pyrolysis products. At the same time, it can efficiently reduce the pyrolysis temperature and improve the energy utilization efficiency. Description of the Drawings

[0018] Figure 1 is the TEM image of the pyrolysis catalyst C1 prepared in Example 1;

[0019] Figure 2 It is a thermogravimetric analysis diagram of the pyrolysis of oil shale by the pyrolysis catalyst C1 in Test Example 1. Detailed implementation mode

[0020] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0021] The present invention mainly aims at the problems that the catalytic ability of the current pyrolysis catalyst is very limited, the pyrolysis efficiency is low, the preparation price of the pyrolysis catalyst is expensive, and it is difficult to realize industrialization. A method for preparing an efficient pyrolysis catalyst and its application are proposed, which can efficiently reduce the activation energy of the oil shale pyrolysis reaction, reduce energy consumption, improve the pyrolysis efficiency of oil shale, and improve the distribution of the pyrolysis products of oil shale, thereby improving the quality of shale oil in the pyrolysis products.

[0022] The first aspect of the present invention provides a pyrolysis catalyst, and the raw materials of the pyrolysis catalyst include: 10%-30% of transition metal salt, 1%-5% of clay mineral, 20%-40% of alkaloid, 15%-35% of alcohol substance, and 5%-10% of urea.

[0023] In the process of pyrolyzing oil shale with the catalyst prepared by the present invention, on the one hand, transition metal ions and clay minerals have the properties of solid acid on the surface of biomass. The Lewis acid on the catalyst can initiate the formation of carbocations from alkanes, and olefins and aromatics can generate carbocations by the Bronsted acid (proton acid) on the catalyst. The carbocations can undergo β-scission to form hydrocarbons with small molecular weights. That is, the formed carbocations can interact with a neutral molecule or between carbocations to produce a series of chemical reactions, promoting the degradation of kerogen into hydrocarbons or the further conversion of pyrolysis hydrocarbons. On the other hand, the free radicals produced by the kerogen in shale and biomass production capacity will interact with each other. This interaction affects the oxygen distribution in the pyrolysis volatiles of biomass, promotes the generation of CO2 and CO, and reduces the generation amount of oxygen components in the liquid products, which helps to improve the quality of shale oil. The two act synergistically in the process of catalytic pyrolysis of oil shale, which greatly improves the catalytic pyrolysis effect of shale.

[0024] The present invention improves the catalytic activity and active sites of the catalyst, thereby efficiently reducing the reaction activation energy and reducing energy consumption.

[0025] In some preferred embodiments of the present invention, the pyrolysis catalyst is made of raw materials with the following mass percentages: transition metal salt 20%-30%, clay mineral 3%-5%, alkaloid 30%-40%, alcohol substance 25%-35%, and urea 5%-8%.

[0026] More preferably, the pyrolysis catalyst is made of raw materials with the following mass percentages: transition metal salt 28%, clay mineral 3%, alkaloid 35%, alcohol substance 28%, and urea 6%.

[0027] In some embodiments of the present invention, the particle size of the pyrolysis catalyst is 5-25 nm, preferably 5-15 nm.

[0028] The pyrolysis catalyst of the present invention has very high catalytic activity when pyrolyzing oil shale. It can not only greatly reduce the activation energy in the pyrolysis process of oil shale, but also help improve the quality of shale oil. And this catalyst has a low price, a very small particle size and is easy to inject into the formation, which is beneficial to realizing industrialization.

[0029] In some embodiments of the present invention, the transition metal salt is selected from one or more of molybdenum salt, iron salt, copper salt and nickel salt.

[0030] In the present invention, the molybdenum salt includes but is not limited to at least one of ammonium molybdate, sodium molybdate and potassium molybdate.

[0031] In the present invention, the iron salt includes but is not limited to at least one of ferric sulfate, ferric chloride and copper nitrate.

[0032] In the present invention, the copper salt includes but is not limited to at least one of copper sulfate, copper chloride, copper nitrate and copper acetate.

[0033] In the present invention, the nickel salt includes but is not limited to at least one of nickel sulfate, nickel chloride, nickel acetate and nickel nitrate.

[0034] In some embodiments of the present invention, the clay mineral is montmorillonite and / or illite.

[0035] In some embodiments of the present invention, the alkaloid is selected from one or more of atropine, nicotine and febrifugine;

[0036] In some embodiments of the present invention, the alcohol substance is selected from one or more of polyethylene glycol, propylene glycol and glycerol.

[0037] The second aspect of the present invention provides a preparation method of a pyrolysis catalyst, and the preparation method includes the following steps:

[0038] React 10%-30% of a transition metal salt, 1%-5% of a clay mineral, 20%-40% of an alkaloid, 15%-35% of an alcohol substance, and 5%-10% of urea by heating to obtain an intermediate;

[0039] First, carbonize the intermediate, and then calcine it to obtain a pyrolysis catalyst.

[0040] According to the present invention, the step of preparing the intermediate is the key point of the preparation method of the present invention. Preparing the intermediate plays a crucial role in the process of preparing the catalyst by the combustion method. They are not only the intermediary for material transformation but also the key to realizing the regulation of material properties.

[0041] According to the present invention, during the reaction process, the alkaloid and urea act as nitrogen sources, the alcohol substance acts as a carbon source, and the clay mineral acts as a catalyst. The two react to form carbon nanodots and dope transition metals on their surfaces.

[0042] In some embodiments of the present invention, the conditions of the reaction include: a reaction temperature of 120-160°C and a reaction time of 5-8 h.

[0043] According to the present invention, the carbonization treatment is to heat a carbon-containing precursor (gel substance) to a certain temperature to cause its thermal decomposition and form a carbon-rich product. In this process, the non-carbon elements (such as hydrogen, oxygen, nitrogen, etc.) of the organic matter will be released in the form of gas, and the remaining carbon atoms will rearrange to form the structure of carbon nanodots.

[0044] In some embodiments of the present invention, the conditions of the carbonization treatment include: a reaction temperature of 180-220°C and a reaction time of 1-3 h.

[0045] According to the present invention, the purpose of calcination is to dope transition metals onto the carbon dots and further purify and improve the properties of the carbon dots.

[0046] In some embodiments of the present invention, the conditions of the calcination include: a reaction temperature of 500-600°C and a reaction time of 4-6 h.

[0047] In some embodiments of the present invention, the transition metal salt is selected from one or more of molybdenum salts, iron salts, copper salts, and nickel salts.

[0048] In some embodiments of the present invention, the clay mineral is montmorillonite and / or illite.

[0049] In some embodiments of the present invention, the alkaloid is selected from one or more of atropine, nicotine, and febrifugine.

[0050] In some embodiments of the present invention, the alcohol substance is selected from one or more of polyethylene glycol, propylene glycol, and glycerol.

[0051] According to the present invention, the preparation method specifically includes the following steps:

[0052] Put 10%-30% of raw material transition metal salt, 1%-5% of clay mineral, 20%-40% of alkaloid, 15%-35% of alcohol substance and 5%-10% of urea into a three-necked flask, then place the three-necked flask in an oil bath pot, control the oil bath temperature to be 120-160°C for heating and reaction for 5-8h to obtain an intermediate; then put the intermediate into a muffle furnace, heat it in an air atmosphere to 180-220°C and maintain it for 1-3h. After the time ends, continue to heat it to 500-600°C for 4-6h, and after natural cooling, obtain a pyrolysis catalyst.

[0053] The catalyst prepared by the present invention is prepared by a combustion method, which is equivalent to a hydrothermal method. The operation process is simple and the preparation method is simple. Moreover, the yield is much higher than that obtained by the hydrothermal method. At the same time, the catalyst prepared by the combustion method has a small particle size, in the nanometer range.

[0054] The third aspect of the present invention provides the use of the pyrolysis catalyst described in the first aspect or the pyrolysis catalyst prepared in the second aspect in the pyrolysis of oil shale or medium-low maturity shale oil.

[0055] The catalyst of the present invention can improve the pyrolysis efficiency of oil shale, improve the distribution of pyrolysis products of oil shale, produce more light products, and improve the quality of shale oil in the pyrolysis products.

[0056] In the present invention, medium-low maturity shale oil refers to shale oil with a vitrinite reflectance of 0.5%-1%.

[0057] The fourth aspect of the present invention provides a method for pyrolyzing oil shale, and the method includes the following steps:

[0058] Mix the oil shale with the pyrolysis catalyst described in the first aspect or the pyrolysis catalyst prepared in the second aspect of the preceding claims, and then carry out catalytic pyrolysis to obtain shale oil and pyrolysis gas after separation.

[0059] In the present invention, the catalyst of the present invention can efficiently reduce the activation energy of the oil shale pyrolysis reaction, reduce energy consumption, and the catalyst can also improve the pyrolysis efficiency of oil shale, improve the distribution of pyrolysis products of oil shale, improve the quality of shale oil in the pyrolysis products, and produce more light products, thereby improving the quality of shale oil in the pyrolysis products.

[0060] In the present invention, using the catalyst of the present invention for catalytic pyrolysis of oil shale can efficiently reduce the pyrolysis temperature and improve the energy utilization efficiency.

[0061] In some embodiments of the present invention, the particle size of the oil shale is less than or equal to 0.105 mm.

[0062] In some embodiments of the present invention, the dosage of the pyrolysis catalyst is 1-5 wt% of the oil shale.

[0063] In some embodiments of the present invention, the conditions for catalytic pyrolysis include: under the protection of an inert gas, heating to 350-550 °C at a rate of 5-20 °C / min, and then holding for 60-120 min.

[0064] Specifically, during the experiment, a mixture of oil shale and the catalyst (1-5 wt% of the mass of the oil shale) is loaded into the reactor. Before the reaction, it is first purged with nitrogen for 10-20 minutes to ensure an oxygen-free environment throughout the process; subsequently, it is heated to the required reaction temperature (350-550 °C) at a rate of 5-20 °C / min (preferably 10-20 °C / min) and held at this temperature for 60-120 min.

[0065] In some embodiments of the present invention, the catalytic pyrolysis is carried out in a retort furnace.

[0066] In some embodiments of the present invention, before mixing, the pyrolysis catalyst is evenly sprayed on the oil shale.

[0067] In some particularly preferred embodiments of the present invention, the method for catalytic pyrolysis of oil shale using the catalyst of the present invention specifically includes the following steps:

[0068] Step 1: Crush and screen the oil shale minerals, and collect the oil shale with a particle size less than or equal to 0.105 mm;

[0069] Step 2: Evenly spray the catalyst prepared above on the oil shale collected in Step 1, stir and mix evenly, and then send it into a retort furnace for catalytic pyrolysis. Cool and separate the oil and gas generated during the catalytic pyrolysis process to obtain shale oil and pyrolysis gas; wherein, the dosage of the catalyst is 1% - 5% of the mass of the collected oil shale.

[0070] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited to the following description.

[0071] For the following examples and comparative examples where no specific conditions are indicated, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments where the manufacturer is not indicated, they are all conventional products that can be obtained through commercial channels.

[0072] In the following examples and comparative examples, the proximate analysis and ultimate analysis data of the oil shale are shown in Table 1.

[0073] Table 1 Proximate analysis and ultimate analysis data of oil shale

[0074] Industrial analysis Content / (wt%) Elemental analysis Content / (wt%) Mad 0.92±0.09 C 15.36±0.18 Vad 19.43±0.13 H 1.88±0.31 Aad 75.31±0.17 <![CDATA[O a > 5.28±0.15 FCad 3.07±0.06 N 0.72±1.81 Qad (kJ / kg) 5814.16±55.45 S 0.53±0.24

[0075] a By difference: O% = 100% - C% - H% - N% - S% - Aad% - Mad%

[0076] By difference refers to the differential method. The differential method is used to calculate the oxygen content in shale to avoid errors caused by oxygen loss during ashing.

[0077] The industrial analysis and elemental analysis parameters of oil shale are measured by the national standards GB / T 212 - 2008 and GB / T 476 - 200 methods.

[0078] Example 1

[0079] Add 28 parts by weight of copper chloride, 3 parts by weight of montmorillonite, 35 parts by weight of atropine, 28 parts by weight of glycerol and 6 parts by weight of urea into a three - necked flask, and heat it in an oil bath at 140 °C for 6 h to obtain an intermediate; put the intermediate into a muffle furnace, heat it in an air atmosphere to 200 °C and maintain it for 2 h, then continue to heat it to 500 °C and heat for 6 h, and after natural cooling, obtain the pyrolysis catalyst C1.

[0080] The TEM image of the pyrolysis catalyst C1 prepared in the above example is as Figure 1 shown, and it can be seen from Figure 1 that the transmission electron microscope image clearly shows that the synthesized catalyst presents a nanosphere morphology with uniform size and distribution. And the particle size prepared in the experiment is mainly distributed around 6.5 nm.

[0081] Test Example 1

[0082] Dissolve 1 g of the pyrolysis catalyst C1 prepared in Example 1 in water, add 99 g of oil shale, and stir evenly; then put it into an oven and dry it at 60 °C for 12 h; after the liquid is dried, dry and grind the product to make a powder.

[0083] Load the catalyst with ω = 1% onto the oil shale by the above method, and then under the experimental conditions of a temperature range of 30 - 800 °C, a heating rate of 5 °C / min, and a nitrogen flow rate of 30 mL / min, put it into a thermogravimetric crucible for thermogravimetric analysis experiment.

[0084] According to the thermogravimetric data analysis of the catalytic effect of the catalyst, the results are as Figure 2 shown, where (a) and (b) are the TG curve and DTG curve of the decomposition of oil shale with or without the catalyst respectively, and it can be seen from Figure 2It can be seen that the addition of the catalyst effectively accelerates the decomposition process of oil shale. It is worth noting that compared with the sample without the catalyst, the shale samples with the catalyst show obvious differences in the TG and DTG curves. After adding the catalyst, the weight reduction rate of the shale sample increases from 14.43% to 19.28%, which prominently indicates that the catalyst can effectively reduce the activation energy required for the reaction. In addition, the DTG curve confirms that the catalyst effectively reduces the initial temperature of oil shale decomposition and the peak temperature of the pyrolysis rate. Specifically, adding the catalyst can reduce the initial pyrolysis temperature of the shale by 64 °C and the peak temperature of the pyrolysis rate by 16 °C. These results show that the catalyst not only promotes the cleavage of organic functional groups in oil shale but also accelerates the pyrolysis rate of hydrocarbons.

[0085] The Coats-Redfern integral method was used to calculate the apparent activation energy of the oil shale sample during the second stage of pyrolysis. The experimental results are shown in Table 2.

[0086] Table 2 Kinetic parameters of the pyrolysis reaction of the sample calculated by the Coats-Redfern model method

[0087] E (KJ / mol) <![CDATA[A(min -1 )]]> Temperature range (°C) R2 Without catalyst 72.89 86.5 335-560 0.9588 With catalyst 43.23 158 271-544 0.91151

[0088] E is the activation energy, KJ / mol; A is the pre-exponential factor, min -1 ; R2 is the linear correlation coefficient

[0089] From the data in Table 2, it can be seen that the Coats-Redfern method was used to determine the kinetic parameters (including E and A) of the pyrolysis of shale organic matter with and without the catalyst. The R2 of all activation energies exceeds 90%, indicating that the calculation results are highly reliable. There is a direct relationship between the pre-exponential factor and the reaction rate, indicating that under similar conditions, an increase in the pre-exponential factor will lead to a faster reaction rate. Contrary to the non-catalytic case, adding the catalyst during pyrolysis results in a significant increase in the pre-exponential factor, which prominently indicates that the addition of the catalyst significantly increases the rate of shale pyrolysis. The catalyst can reduce the activation energy of oil shale pyrolysis by 29.66 KJ / mol.

[0090] Test Example 2

[0091] Put 1 g of the pyrolysis catalyst C1 prepared in Example 1 and 99 g of oil shale into the center of a quartz tube, and then ventilate nitrogen into the quartz tube at a flow rate of 100 mL / min for 30 min to maintain an anoxic atmosphere. The heating temperature ranges from 350 °C to 550 °C (in a gradient of 50 °C each), and heat for 60 min at each temperature point, and then collect the shale oil, pyrolysis gas and char produced by the reaction. In a round-bottom flask, use an extractant (toluene) to perform extraction distillation on the collected liquid mixture. After oil-water separation, the masses of water and oil can be calculated. After pyrolysis is completed, the mass of the remaining solid residue can be regarded as the mass of char, and the shale oil yield can be calculated based on the change in mass in the round-bottom flask. The results are shown in Table 3.

[0092] Table 3 Pyrolysis products of oil shale at different temperatures

[0093]

[0094] As can be seen from the data in Table 3, in the range of 350 - 550 °C, as the pyrolysis temperature increases, the char yield gradually decreases, the shale oil yield gradually increases, and the pyrolysis gas yield gradually increases (the yield reaches the maximum at 500 °C). It can be seen that after adding the pyrolysis catalyst C1 during the pyrolysis of oil shale, the oil (gas) production rate is significantly enhanced. Among them, the oil production rate increased by 20.42% at 500 °C.

[0095] Example 2

[0096] Put 10 parts by weight of copper chloride, 5 parts by weight of montmorillonite, 40 parts by weight of choline chloride, 35 parts by weight of glycerol and 10 parts by weight of urea into a three-necked flask, and heat in an oil bath at 160 °C for 5 h to obtain an intermediate; put the intermediate into a muffle furnace, heat in an air atmosphere to 220 °C and maintain for 1 h, continue to heat up to 600 °C and heat for 4 h, and after natural cooling, obtain the pyrolysis catalyst C2.

[0097] Example 3

[0098] Put 30 parts by weight of copper chloride, 2 parts by weight of montmorillonite, 30 parts by weight of choline chloride, 30 parts by weight of glycerol and 8 parts by weight of urea into a three-necked flask, and heat in an oil bath at 120 °C for 8 h to obtain an intermediate; put the intermediate into a muffle furnace, heat in an air atmosphere to 180 °C and maintain for 3 h, continue to heat up to 550 °C and heat for 5 h, and after natural cooling, obtain the pyrolysis catalyst C3.

[0099] Example 4

[0100] Prepare the pyrolysis catalyst C4 according to the method of Example 1, except that 16 parts by weight of copper chloride, 3 parts by weight of montmorillonite, 40 parts by weight of atropine, 35 parts by weight of glycerol and 6 parts by weight of urea are put into a three-necked flask; the remaining steps are the same as those in Example 1.

[0101] Example 5

[0102] The pyrolysis catalyst C5 was prepared according to the method of Example 1, except that 30 parts by weight of copper chloride, 4 parts by weight of montmorillonite, 32 parts by weight of atropine, 28 parts by weight of glycerol and 6 parts by weight of urea were put into a three-necked flask; the remaining steps were the same as those in Example 1.

[0103] Example 6

[0104] The pyrolysis catalyst C6 was prepared according to the method of Example 1, except that 28 parts by weight of nickel sulfate, 3 parts by weight of montmorillonite, 35 parts by weight of atropine, 28 parts by weight of glycerol and 6 parts by weight of urea were put into a three-necked flask; the remaining steps were the same as those in Example 1.

[0105] Example 7

[0106] The pyrolysis catalyst C7 was prepared according to the method of Example 1, except that 28 parts by weight of manganese chloride, 3 parts by weight of montmorillonite, 35 parts by weight of atropine, 28 parts by weight of glycerol and 6 parts by weight of urea were added to a three-necked flask; the remaining steps were the same as those in Example 1.

[0107] Example 8

[0108] 28 parts by weight of copper chloride, 3 parts by weight of montmorillonite, 35 parts by weight of atropine, 28 parts by weight of glycerol and 6 parts by weight of urea were put into a three-necked flask, and heated in an oil bath at 140 °C for 6 h to obtain an intermediate; the intermediate was put into a muffle furnace and heated to 500 °C in an air atmosphere and maintained for 6 h, and then naturally cooled to obtain the pyrolysis catalyst C8.

[0109] Comparative Example 1

[0110] The pyrolysis catalyst D1 was prepared according to the method of Example 1, except that 4 parts by weight of montmorillonite, 32 parts by weight of atropine, 28 parts by weight of glycerol and 6 parts by weight of urea were put into a three-necked flask; the remaining steps were the same as those in Example 1.

[0111] Comparative Example 2

[0112] The pyrolysis catalyst D2 was prepared according to the method of Example 1, except that 5 parts by weight of copper chloride, 4 parts by weight of montmorillonite, 32 parts by weight of atropine, 28 parts by weight of glycerol and 6 parts by weight of urea were put into a three-necked flask; the remaining steps were the same as those in Example 1.

[0113] Comparative Example 3

[0114] The pyrolysis catalyst D3 was prepared according to the method of Example 1, except that 40 parts by weight of copper chloride, 4 parts by weight of montmorillonite, 32 parts by weight of atropine, 28 parts by weight of glycerol and 6 parts by weight of urea were put into a three-necked flask; the remaining steps were the same as those in Example 1.

[0115] Application Example

[0116] 1 g of each of the above-prepared pyrolysis catalysts C1-C8 and D1-D3 and 99 g of oil shale were respectively placed in the center of a quartz tube, and then nitrogen was ventilated into the quartz tube at a flow rate of 100 mL / min for 30 min to maintain an anoxic atmosphere. The heating temperature was from 350 °C to 550 °C, and then the shale oil, pyrolysis gas, and char produced by the reaction were collected.

[0117] Online detection of the compositional changes of the pyrolysis products (shale oil) was carried out using Py-GC / MS analysis. During the pyrolysis reaction of oil shale, these catalysts showed good deoxygenation and aromatization performance, significantly reducing the yields of oxygen-containing compounds and esters, while significantly increasing the yields of olefins and alkanes. Compared with the pyrolysis of shale alone, the addition of the catalyst increased the yield of olefins by 12.17% and the content of alkanes by 3.16%. The distribution of the pyrolysis products is shown in Table 4.

[0118] Table 4 Distribution of Pyrolysis Products under Different Catalytic Conditions

[0119]

[0120] As can be seen from the data in Table 4, the pyrolysis catalysts C1-C8 obtained in Examples 1-8 had significantly better effects during the pyrolysis of oil shale. These catalysts showed excellent performance in promoting deoxygenation and aromatization reactions, resulting in a significant reduction in the yields of oxygen-containing compounds and esters, and a significant increase in the yields of olefins and alkanes. Through the compositional analysis of the pyrolysis products (shale oil) of oil shale catalyzed by the catalysts C1-C6 prepared in Examples 1-6, it can be known that these catalysts had stable and excellent catalytic performance within the raw material ratio range of the formula, and the performance fluctuations were small. In contrast, although the catalytic effect of catalyst C7 using manganese metal salt in Example 7 was weakened, it still showed good catalytic activity. The catalytic effect of catalyst C8 without carbonization treatment in Example 8 was equivalent to that of catalysts C1-C6 but was weakened, but it still showed good catalytic activity. Further comparative analysis showed that for the catalysts D1-D3 prepared in Comparative Examples 1-3, when the raw material ratio exceeded the predetermined formula range or the raw material components changed, their catalytic efficiency decreased significantly compared with the catalysts in the standard examples.

[0121] Compared with pyrolysis without adding a catalyst, pyrolysis with catalyst C1 increased the yield of olefins by 12.17% and the content of alkanes by 3.16%, which highlights the important role of the catalyst in improving the quality and yield of hydrocarbon products.

[0122] As can be seen from the above, the pyrolysis catalyst prepared by the embodiments of the present invention has the advantages of high catalytic activity, improving the pyrolysis efficiency of oil shale, improving the distribution of pyrolysis products of oil shale, producing more light products, and improving the quality of shale oil in pyrolysis products, etc.

[0123] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A pyrolysis catalyst, characterized in that, The raw materials of the pyrolysis catalyst include: 10%-30% of transition metal salt, 1%-5% of clay mineral, 20%-40% of alkaloid, 15%-35% of alcohol substance, and 5%-10% of urea.

2. The pyrolysis catalyst according to claim 1, wherein, The pyrolysis catalyst is made from the following raw materials by mass percentage: 20%-30% of transition metal salt, 3%-5% of clay mineral, 30%-40% of alkaloid, 25%-35% of alcohol substance, and 5%-8% of urea.

3. The pyrolysis catalyst according to claim 1 or 2, wherein The particle size of the pyrolysis catalyst is 5-25 nm, preferably 5-15 nm.

4. The pyrolysis catalyst according to claim 1 or 2, wherein, The transition metal salt is selected from one or more of molybdenum salt, iron salt, copper salt, and nickel salt; and / or, the clay mineral is montmorillonite and / or illite.

5. The pyrolysis catalyst according to claim 1 or 2, wherein, The alkaloid is selected from one or more of atropine, nicotine, and febrifugine; and / or, the alcohol substance is selected from one or more of polyethylene glycol, propylene glycol, and glycerol.

6. A preparation method of a pyrolysis catalyst, characterized in that, The preparation method includes the following steps: Heat 10%-30% of transition metal salt, 1%-5% of clay mineral, 20%-40% of alkaloid, 15%-35% of alcohol substance, and 5%-10% of urea to react to obtain an intermediate; Carry out carbonization treatment on the intermediate first, and then carry out calcination to obtain the pyrolysis catalyst.

7. The preparation method according to claim 6, wherein, The conditions of the reaction include: reaction temperature 120-160 °C, reaction time 5-8 h.

8. The preparation method according to claim 6, wherein, The conditions of the carbonization treatment include: reaction temperature 180-220 °C, reaction time 1-3 h; and / or, the conditions of the calcination include: reaction temperature 500-600 °C, reaction time 4-6 h.

9. The preparation method according to claim 6, wherein, The transition metal salt is selected from one or more of molybdenum salt, iron salt, copper salt, and nickel salt; and / or, the clay mineral is montmorillonite and / or illite; and / or, the alkaloid is selected from one or more of atropine, nicotine, and febrifugine; and / or, the alcohol substance is selected from one or more of polyethylene glycol, propylene glycol, and glycerol.

10. Application of the pyrolysis catalyst according to any one of claims 1-5 or the pyrolysis catalyst prepared by the preparation method according to any one of claims 6-9 in the pyrolysis of oil shale or medium-low maturity shale oil.

11. A method for pyrolyzing oil shale, characterized in that, The method includes the following steps: Mix oil shale with the pyrolysis catalyst according to any one of claims 1-5 or the pyrolysis catalyst prepared by the preparation method according to any one of claims 6-9, and then carry out catalytic pyrolysis, and after separation, shale oil and pyrolysis gas are obtained.

12. The method according to claim 11, wherein, The particle size of the oil shale is less than or equal to 0.105 mm.

13. The method according to claim 11, wherein, The dosage of the pyrolysis catalyst is 1-5 wt% of the oil shale.

14. The method according to claim 11, wherein The conditions of the catalytic pyrolysis include: under the protection of an inert gas, heat up to 350-550 °C at a rate of 5-20 °C / min, and then hold for 60-120 min; Preferably, the catalytic pyrolysis is carried out in a retort furnace.

15. The method according to claim 11, wherein, Before mixing, the pyrolysis catalyst is evenly sprayed on the oil shale first.

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