CN103242882A - Method for producing oil by using co-liquefaction of cotton stalks and coal without adding catalyst - Google Patents

Abstract

The invention discloses a method for performing co-liquefaction of cotton stalks and coal without adding a catalyst. The method comprises the following steps of: pulverizing raw materials of the cotton stalks and coal powder in a mass proportion of 2 to 1 and adding into a kettle body for high-pressure reaction; adding a solvent tetrahydrofuran solution in a mass proportion that the solvent to the raw materials is 1.75 to 1 and sealing the kettle body; introducing hydrogen into the kettle body until the pressure in the kettle is 3MPa; opening a heating furnace to heat; opening a stirrer in the high-pressure reaction kettle to stir in a velocity of 250r/min for 45 minutes to obtain a reaction liquid; exhausting the air in the kettle body; taking out the reaction liquid and extracting the reaction liquid by using a normal hexane solution to obtain oil; drying the extracted solid product and extracting the solid product by using the tetrahydrofuran solution to obtain sparse asphalt; drying the extracted solid product and extracting the solid product by using the tetrahydrofuran solution to obtain former sparse asphalt; drying the extracted solid product to residue slag during liquefaction; and obtaining oil productivity in the process through an equation of oil productivity plus sparse asphalt yield plus former sparse asphalt yield.

Description

A method for co-liquefying oil with cotton stalks and coal without adding catalyst

technical field

The invention relates to a method for producing oil by co-liquefying cotton stalks and coal without adding a catalyst.

Background technique

In the 1980s, human beings are faced with the dilemma of the depletion of fossil energy such as oil and natural gas and the environmental pollution caused by the extensive use of fossil energy. As a kind of non-renewable energy, fossil energy is exploited on a large scale under the ever-increasing energy demand of people, which leads to the rapid reduction of its reserves and will eventually be exhausted. Under such circumstances, people urgently need to find a substitute for fossil energy, and biomass and coal energy are undoubtedly strong competitors for this position.

First of all, biomass usually refers to various substances derived from plants, mainly various plants, trees and crops, as well as municipal solid waste, seaweed and livestock manure. Biomass energy is a renewable energy source. Compared with non-renewable energy sources such as fossil energy, which takes millions of years to obtain, it is "renewable" - that is, it can be regenerated in a short period of time - This former unparalleled advantage. In addition, since the carbon element in biomass comes from carbon dioxide gas in the atmosphere, the use of biomass energy will not increase the total amount of carbon dioxide gas in the atmosphere, greatly reducing environmental pollution. Based on the above reasons, the development and utilization of biomass energy has become a research hotspot.

In order to efficiently use biomass energy, biomass must be converted into high calorific value, easy-to-handle biomass fuel. China is the second largest energy consuming country in the world. The shortage of energy supply has seriously affected the development of my country's economy. At the same time, China is a large agricultural country with abundant biomass resources. Among them, Xinjiang is rich in biomass resources such as cotton stalks and fruit shells. The cotton planting area alone reaches 18.64 million mu every year, but the large amount of cotton stalks produced has not been fully utilized in high-quality except for civilian fuel. The development and utilization of biomass energy can not only provide sufficient energy and power for sustainable development, but also protect the ecological environment.

Biomass resources include wood and wood waste, crops and their by-products, municipal solid waste, animal waste, food processing waste, and waste from aquatic plants and algae, etc., generally divided into three categories: garbage, forest resources and energy crops. Biomass conversion produces energy in many forms, such as power generation, heating, as fuel for vehicles, and to provide heat for industrial equipment. Biomass utilization and conversion technologies can be divided into four categories: direct combustion technology, thermochemical conversion technology, biochemical conversion technology, and solidification molding technology. Thermochemical conversion technology can be divided into: gasification, pyrolysis, supercritical extraction and direct liquefaction technology. At present, the main method of large-scale centralized treatment of biomass is pyrolysis gasification, but it has problems such as low calorific value of gas generated by gasification, difficult storage and transportation, and high cost of small-scale power generation. Rapid pyrolysis of biomass to produce oil is a cutting-edge technology in the research and development of biomass energy in the world, but this technology requires high equipment and harsh reaction conditions. Compared with fast pyrolysis liquefaction technology, direct biomass liquefaction, that is, high-pressure liquefaction, has relatively mild reaction conditions, relatively low equipment requirements, and is easy to produce on an industrial scale, so it is one of the efficient utilization methods of biomass resources. Biomass high-pressure liquefaction conversion technology has been paid more and more attention, and has become one of the hot topics studied by many scholars.

Secondly, coal is a solid organic combustible product produced by ancient plants through complex biochemical, physical chemical and geochemical transformations. According to the coal-forming plants, coal can be divided into two categories: "humic coal" and "sapropel peat". Coal produced by higher plants is called sapropel peat. The coal with large reserves and wide distribution in my country and even in the world is mainly humic coal, which is generally referred to as humic coal. The coal formation process includes peatization stage and coalification stage. The latter can be divided into diagenesis and metamorphism. Two phases. The coal-forming theory that has formed a consensus holds that coal-forming plants first transform into peat, and then can be transformed into lignite, sub-bituminous coal, bituminous coal, and anthracite in turn, or pause at a certain stage. The whole process can be called the coalification stage. The degree of metamorphism from lignite is called "degree of coalification".

Direct coal liquefaction is one of the important technologies to alleviate my country's oil shortage. Currently, Shenhua Group is building the first million-ton demonstration production line. The reaction kinetics of hydrogenation liquefaction of coal and circulating solvent at high pressure and high temperature is one of the key scientific issues of direct liquefaction technology, and has become the focus of domestic and foreign researchers. Some researchers used tetralin as a solvent and used different catalysts to study the mechanism and kinetics of coal hydrogenation liquefaction. For example, Robert et al. proposed the asphaltenes before coal formation through direct liquefaction experiments on 69 kinds of high volatile bituminous coals. A simple series reaction path with asphaltene, pre-asphaltenes and asphaltenes to generate oil and gaseous products ^; Japan has used coal liquefaction cycle solvents for kinetic studies, such as Akira KIDOGUCHI et al. Coal and Indonesian Tanitoharum coal have carried out kinetic research on the initial stage of hydrogenation liquefaction reaction. It is believed that coal can be divided into fast conversion components, slow conversion components and non-transformation components according to the liquefaction properties, and the fast conversion components can be converted into Pre-asphaltene, asphaltene, oil and gaseous products, the slow conversion components are only converted into pre-asphaltenes and asphaltenes, and the reaction rate constants are obtained through experiments; Onozaki et al. conducted a 150t/d NEDOL Chinese device Studies of liquefaction kinetics suggest more complex reaction networks. Many studies have shown that the liquefaction kinetics of different coal types and different reaction conditions are different.

It is well known that oil as an energy reserve resource is less than coal and biomass, and the distribution is uneven, and the contradiction between oil supply and demand is becoming increasingly prominent. Our country is rich in coal, rich in biomass, and poor in oil resources, which determines that the energy development must be dominated by coal and biomass. For a long time, coal has always accounted for more than 70% of my country's energy consumption structure. According to the forecast: in 2020, my country's dependence on imported oil will reach 50%, and in 2030 it will reach 74%. It can be seen that coal has become the first choice to find a resource that can replace oil. The development of coal and biomass oil production technology and related chemical industries, and the realization of coal and biomass instead of oil have important practical and long-term historical significance. It will solve the shortage of oil resources in our country, balance the energy structure, ensure energy security and An important strategic measure for the sustainable and stable development of the national economy. The co-liquefaction of biomass and coal refers to the conversion of solid coal and biomass into liquid fuels, chemical raw materials and other products through chemical processing methods in a certain proportion.

Biomass high-pressure liquefaction technology refers to the technology of liquefying biomass to produce liquid products under the conditions of relatively high pressure, certain temperature and the presence of solvents and catalysts. The direct coal liquefaction technology refers to coal under appropriate temperature and pressure, catalytic hydrocracking, thermal cracking, solvent, extraction, non-catalytic cracking, etc. The deep transformation process of heteroatoms.

Contents of the invention

The purpose of the present invention is to provide a method for co-liquefying cotton stalks and coal to produce oil by using the high-pressure reactor.

In order to achieve the above object, the present invention adopts the following scheme:

A method for co-liquefying cotton stalks and coal without adding a catalyst, characterized in that it comprises the following steps:

A, raw material cotton stalks, pulverized coal are pulverized by the mass ratio of 2: 1 and then added to the autoclave body of high pressure reaction, by solvent: the mass ratio of raw material=1.75: 1 is added solvent tetrahydrofuran solution, then the autoclave body is sealed;

B. Charge hydrogen into the sealed kettle body until the pressure in the kettle body is 3MPa, and turn on the heating furnace to adjust the temperature to 380°C for heating, and turn on the stirrer in the high-pressure reaction kettle to adjust the stirring speed to 250r/min for stirring. Reacted for 45min to obtain the reaction solution;

C, after venting the gas in the kettle body, take out the reaction solution and extract it with n-hexane solution to obtain oil;

D, dry the extracted solid product, then extract with toluene solution to obtain bitumen;

E, drying the extracted solid product, and then extracting it with a tetrahydrofuran solution to obtain pre-asphaltene;

F, the extracted solid product is dried to obtain the liquefaction process residue;

G. Oil yield + asphalt dilute yield + former asphalt dilute yield to get the oil yield of this process.

The optimal process conditions of the method for co-liquefaction of cotton stalks and coal to produce oil according to the present invention are as follows: the reaction temperature is 380°C, the reaction pressure is 3MPa, the stirring rate is 250r/min, the solvent (g)/raw material (g) The ratio is 1.75, the reaction time is 45min, the coal (g)/cotton stalk (g) ratio is 1:2, and the oil yield is 65% under these technological conditions.

In the present invention, in order to determine optimum liquefaction condition, done following test:

1. Table of horizontal factors

(1) investigate the influence of these four factors of reaction time, reaction temperature, solvent/raw material ratio, coal/cotton stalk ratio on liquid yield; (2) find out the influence on liquid yield in above-mentioned four factors; (3 ) to determine the process conditions when the oil yield is the highest.

Table 1 Response variables and factors

2. Orthogonal experimental design

Using cotton stalks and coal as raw materials, experiments with 4 factors and 3 levels were carried out according to the L ₉ 3 ⁴ orthogonal table. In Table 3-2, factor A represents the reaction temperature, level 1 is 380°C, level 2 is 420°C, level 3 is 460°C; factor B represents the mass ratio of solvent/raw material, level 1 is 1.75, level 2 is 2.25, level 3 2.75; C factor represents the reaction time, level 1 is 45min, level 2 is 60min, level 3 is 75min; D factor represents the mass ratio of coal/cotton stalk, level 1 is 1:1, level 2 is 1:2, level 3 2:1

Table 2 Orthogonal table

3 Analysis of experimental results

After completing the experiment according to the orthogonal table, a calculation is made on the obtained data, and the calculation results are shown in Table 3:

Table 3 Analysis of products after liquefaction

In the analysis of the liquefied products in Table 3, the oil yield, asphaltene yield, pre-asphaltene yield, gas yield, conversion rate, slag yield and liquid yield were calculated according to the following formula:

First of all, m ₀₀ , m ₀ , m ₁ , m ₂ , and m ₃ in the table represent respectively: m ₀₀ includes the mass of cotton, extractor, and filter paper tube, and m ₀ is the mass of cotton, extractor, filter paper tube, and liquid product before catalysis m ₁ is the amount of substances that cannot be tolerated in n-hexane, m ₂ is the amount of substances that cannot be tolerated in toluene, and m ₃ is the amount of substances that cannot be tolerated in THF.

1 Oil yield:

Among them, the solvent quality:

Solvent quality = (solvent/raw material) × quality of raw material

2. Asphaltene yield:

3 Pre-asphaltene yield:

4 Slag yield:

5 conversion rate.

η _corn =100-η _res

6 liquid yield.

η _liq = η _ell + η _as + η _pa

7. Gas production rate:

η _gas = η _corn - η _liq

4 Conclusion

Nine sets of orthogonal experiments were analyzed, K ₁ , K ₂ , K ₃ , k ₁ , k ₂ , k ₃ , R values were calculated, and the optimal liquefaction conditions were found. The calculation results are shown in Table 4:

Table 4 Orthogonal test results and analysis

According to K ₁ , K ₂ , K ₃ , k ₁ , k ₂ , k ₃ , and R value, the order from primary to secondary that affects the liquid yield is: coal g/cotton stalk (g)>reaction time>reaction temperature> Melt g/raw material g.

According to the data calculation, such a result is obtained: when the reaction temperature is 380°C, the reaction pressure is 3MPa, the reaction speed is 250r/min, the solvent g/raw material g ratio is 1.75, and the reaction time is 45min, coal g/cotton stalk (g) The highest liquid yield is 67.59% when the ratio is 1:2.

Detailed ways

The present invention will be further described below in conjunction with specific embodiment:

Example 1

The raw material cotton stalks and coal powder are pulverized according to the mass ratio of 2:1, and then added to the autoclave body for high pressure reaction, and the solvent THF solution is added according to the mass ratio of solvent: raw material = 1.75:1, and then the autoclave body is sealed;

Fill the sealed kettle with hydrogen until the pressure in the kettle is 3MPa, and turn on the heating furnace to adjust the temperature to 380°C for heating, turn on the stirrer in the high-pressure reactor and adjust the stirring speed to 250r/min for stirring, and react for 45min , to obtain the reaction solution;

After the gas in the kettle was emptied, the reaction solution was taken out and extracted with n-hexane solution to obtain oil;

The extracted solid product is dried, and then extracted with toluene solution to obtain asphaltenes;

drying the extracted solid product, and then extracting it with tetrahydrofuran solution to obtain pre-asphaltene;

The extracted solid product is dried to obtain the residue of the liquefaction process;

The oil yield of this process is obtained by oil yield + bitumen thin yield + former bitumen thin yield.

The optimal process conditions of the method for co-liquefaction of cotton stalks and coal to produce oil according to the present invention are as follows: the reaction temperature is 380°C, the reaction pressure is 3MPa, the stirring rate is 250r/min, the solvent (g)/raw material (g) The ratio is 1.75, the reaction time is 45min, the coal (g)/cotton stalk (g) ratio is 1:2, and the oil yield is 65% under these technological conditions.

Claims (1)

1. one kind is not added liquefy the altogether method of system oil of catalyzer cotton stalk and coal, it is characterized in that may further comprise the steps:

A, raw material cotton stalk, coal dust are pulverized the kettle that the back adds reaction under high pressure by 2: 1 mass ratio, press solvent: the mass ratio adding solvents tetrahydrofurane solution of raw material=1.75: 1 seals kettle then;

B, to the sealing after kettle in charge into hydrogen, be 3MPa until the kettle internal pressure, and open process furnace and adjust the temperature to 380 ℃ and heat, open agitator in the autoclave and regulate and stir speed to stirring to 250r/min, reaction 45min obtains reaction solution;

C, with after the gas emptying in the kettle, take out described reaction solution and extract with hexane solution, get oily;

D, the solid product after will extracting carry out drying treatment, adopt the toluene solution extraction then, and it is rare to get pitch;

E, the solid product after will extracting carry out drying treatment, adopt the tetrahydrofuran solution extraction then, and pitch is rare before getting;

Solid product after F, the extraction carries out drying treatment and gets the liquefaction process residue;

G, the rare productive rate of oily productive rate+pitch+rare productive rate of preceding pitch get the oily productive rate of this process.