JPS59124990A - Hydro-thermal cracking of coal - Google Patents

Abstract

PURPOSE:To obtain gasoline fraction and fuel oil with high yields, by separating a reaction product of coal and hydrogen into vapor and solid phases, bringing the solid phase into contact with hydrogen and hydrogenating the vapor phase. CONSTITUTION:Hydrogen gas heated to 550-900 deg.C is forced into a reaction vessel under the pressure of 25-250kg/cm<2>. Pulverized coal having a particle size of 100 mesh or smaller is fed continuously in the coal/hydrogen gas ratio of 10:1-2:3 by weight and the reaction product is separated into vapor and solid phases. The solid phase is brought into contact with hot hydrogen gas to form a gaseous product. The vapor phase and the gaseous product are made to undergo hydrogenation reaction and the reaction product is cooled rapidly. EFFECT:Ratio of hydrogen for hydrogenation to hydrocarbon produced by the reaction is reduced to a great extent, for formation of methane gas is controlled and the yield of fuel oil is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for hydrogenation and pyrolysis of coal, and more specifically, a method for rapidly pyrolyzing coal in the presence of hydrogen to obtain gasoline fractions and fuel oil in high yield. In recent years, coal, which is the most abundant of all fossil fuel resources and is widely distributed throughout the world, has been reintroduced as an industrial energy source to replace oil, as one of the means to cope with the future depletion of oil resources. It's starting to be appreciated. However, coal is an extremely complex sieve molecular compound, and in addition to its main components carbon and hydrogen, it also contains considerable amounts of heterogeneous atoms such as oxygen, nitrogen, and sulfur, as well as ash, so it cannot be burned as is. Not only does it generate a large amount of atmospheric dye, but it also has a lower calorific value than petroleum.
Many issues remain to be resolved, including problems with transportation and storage.

As a means of solving these essential problems with coal, there are many methods to liquefy coal, remove petroatoms and ash, and obtain clean fuel oil, fuel scum, and other high value-added chemical raw materials. was proposed. Typical examples of these methods include, for example, extracting coal with a solvent, liquefying coal in the presence of hydrogen or a hydrogen donor, and liquefying or gasifying coal in the presence of hydrogen. Examples include a method in which coal is liquefied or gasified in an inert gas. In addition, as a method to directly obtain light oil and gas by heating coal, by jetting finely pulverized coal into a high-temperature, high-pressure hydrogen stream, it is possible to directly obtain light oil or gas. A method of high-speed hydrogenation pyrolysis is also known. This method uses, for example, crushed coal at a pressure of 50 = 250 f/cA (
(gauge pressure) and into a hydrogen stream at a temperature of 600 to 1200°C, the coal is rapidly heated at a rate of 103°C/second or more, and the hydrogen pyrolysis is performed, and the reaction products are methane, ethane, Contains carbon dioxide, carbon oxide, hydrogen sulfide, ammonia, hydrocarbons with 3 to 5 carbon atoms, water, gasoline fraction, fuel oil (aromatic compounds with 10 or more carbon atoms and high-boiling point tar), and ash called char. Solid products etc. are obtained.

In the past, many studies have been conducted to suppress the production of methane and increase the conversion rate of high-value-added gasoline fractions to light oils in such high-speed hydropyrolysis methods of coal, but the results remain unsatisfactory. Should be practical, the method is unknown.

In view of these circumstances, the inventors of the present invention have conducted intensive research to improve the conversion rate to a coal fraction in the conventional high-speed hydrogenation pyrolysis method, and have found that gasoline fraction can be directly produced from coal. In addition to this, the intermediate liquid product is further hydrogenolyzed and lightened, and the latter force is dominant overall, so that the It has been found that increasing the conversion rate requires increasing the absolute amount of the liquid product,
The present invention was made based on this knowledge.

That is, the present invention involves heat-treating coal in the presence of hydrogen to liquefy and turn it into scum, including (a) a step of ejecting fine coal powder into a stream of hot hydrogen scum to rapidly heat it and cause it to react; (b) A step of separating the anti-Kl',- product obtained by the above reaction into a gas phase and a solid phase, (c) A step of causing the solid phase separated in the step (b) to undergo a contact reaction with heated hydrogen gas. Step 5.) The gaseous phase separated in step (b) and the gaseous product obtained in step 09 are further subjected to a hydrogenation reaction. as well as(
The step of rapidly cooling the reaction product obtained in step 1) is
The present invention provides a method for aqueous deep pyrolysis of coal, which is characterized in that it is carried out continuously.

According to the method of the present invention, a kalin fraction can be obtained from coal in high yield, the generation of methane gas due to the higher decomposition of lower hydrocarbons such as ethane produced as a by-product is suppressed, and fuel oil can be produced. As the amount increases, the amount of hydrogen for hydrogenation relative to the amount of hydrocarbons produced by the reaction can be greatly reduced.

By the way, in the present invention, there are mainly two types of reactions that can be considered as reactions for converting coal into a coal fraction.

One is that simple thermal decomposition of coal cleaves small covalent bonds in the bond dissociation process, and the generated free radicals cause hydrogen abstraction, dehydrogenation, C bonding, cyclization, and other competitive reactions of decomposition and polycondensation. This is a solid phase reaction in which the pyrolysis liquid hydrocarbon product (hereinafter referred to as liquid product) is stabilized and diffused into the gas phase in a gaseous state.
This is a gas phase reaction in which the liquid product produced in the same phase reaction is hydrogenolyzed and further reduced in molecular weight.

The thermal decomposition rate in the former in-phase reaction is considered to be relatively fast, but the reaction rate at which the solid product is further hydrogenated and thermally decomposed is quite slow, and the gas and liquid products change from the solid phase to the gas phase. The rate of diffusion into the reaction zone is slower than the rate of thermal decomposition, and since there is also a liquid product adsorbed within the solid product, the longer the residence time of the solid product in the reaction zone, the greater the amount of liquid product. increases in power.

On the other hand, gas phase reaction is a reaction in which a gasoline fraction is produced by the hydrogenolysis reaction of the liquid product produced and diffused from the solid phase reaction. In order to suppress the higher-order hydrogenolysis reaction of lower hydrocarbons such as ethane to methane, it is necessary to carry out the reaction at a temperature similar to that of the dealkylation reaction and with a shorter residence time than the solid phase reaction. .

Therefore, in order to increase the conversion rate from coal to gasoline fraction, the reaction conditions must be such that a large amount of liquid product that can become gasoline fraction is produced in solid phase reaction without breaking, and that liquid product in gas phase reaction is By selecting reaction conditions such that the rate of hydrogenolysis of the product is faster than the rate of hydrogenolysis of the Kallin fraction, an ideal reaction process can be realized.

The coal used in the method of the present invention is preferably pulverized as much as possible;
Preferably, the particle size is adjusted to be 200 mesh or less.

Further, the hydrogen gas flow in step (a) is preferably formed in an atmosphere consisting essentially of hydrogen gas, but for example, inert gas at about 30% by volume, fine ice vapor thereof, carbon dioxide gas, etc. , -V carbon, methane, etc. may be diluted. In the step (a), such a hydrogen gas stream is heated into the reaction vessel and is usually heated to a temperature of 25 to 250 ml.
After being press-fitted to a gauge pressure of Kq/crA, pulverized coal was injected into the reaction vessel to a temperature of 550 to 900°C.
The reaction is carried out by rapid heating at . Since the heating rate of the coal at this time is higher, it is better to increase the liquid product, so a heating rate of usually 1000° C./second or more, preferably 5000° C./second or more is used.

In addition, in the method of the present invention, the reaction temperature in step ll-i is preferably selected in the range of 550 to 900°C.

When this reaction temperature exceeds 900°C, higher hydrogenation of gasoline fractions and hydrocarbons having 2 to 5 carbon atoms obtained by hydrogenolysis of liquid products produced in solid phase reactions occurs in gas phase reactions. Since the amount of methane gas produced increases due to the decomposition reaction, the selectivity to gasoline fraction decreases, and moreover, the amount of hydrogen gas consumed increases.

On the other hand, below 550°C, the rate of thermal decomposition of coal in the solid phase reaction is slow and the thermal decomposition is not sufficient, and the rate of hydrogenation of the liquid product in the gas phase reaction is slow, and the rate of hydrogen decomposition is slow. not enough. A particularly preferred reaction temperature is 57
It is in the range of 0 to 870°C.

Note that the reaction temperatures in each step (a) to (b) do not necessarily have to be the same, and a temperature gradient may be provided within each step.

Next, to explain the reaction time in step (a) to), within the reaction temperature range mentioned above, the liquid product in the reaction product is in a gaseous state, and in step (b) to) When the reaction progresses in the solid state, (a)
The total residence time of the same phase progressing in the order of (b) and (c) is 3
If it is shorter than 0 seconds, the diffusion from the solid phase reaction zone to the gas phase reaction zone and the hydrogenation thermal decomposition reaction of the char will be insufficient, resulting in insufficient increase of the liquid product to the gas phase reaction. In addition, as the total residence time of the solid phase becomes longer (1 hour), the effect becomes smaller and the amount of solid phase retained increases, requiring the reactor to be larger in size, which becomes uneconomical. b), (b)
The total residence time of the solid phase in step (c) is preferably in the range of 30 seconds to 1 hour.

On the other hand, if the total residence time of the gas phase that progresses in the order of (a), (b), and (b) or the subgas phase that progresses in the order of (c), and (b) is short, the conversion rate to gasoline fraction will decrease. The improvement effect cannot be expected, and conversely, if the residence time is too long, the decomposition of the gasoline fraction will proceed too much, so the residence time of both gas phases is shorter than the total residence time of the solid phase, and 1-120 It is preferable to select a time within seconds. However, the residence time of the solid phase and gas phase in each step is not uniquely determined because the shape of the equipment differs depending on the type of coal.

In the method of the present invention, since the pressure in steps (a) to (e) is a hydrogen cracking reaction, increasing the pressure will increase the conversion rate to gasoline fraction, but if the pressure is increased beyond a certain point, the effect will be small. In addition, since it is economically disadvantageous in terms of equipment, a range of 25 to 250 Kg/cni-G is preferable, and a range of 35 to 200 Kg/cni-G is preferable. In step (a)), in order to stop the reaction in step (b), the reaction product is preferably rapidly cooled to a temperature below 450° C. in this case.

In the method of the present invention, the ratio between the amount of pulverized coal supplied (anhydrous, ashless basis) and the amount of reactive hydrogen gas supplied varies depending on the type of coal and the composition of the required reaction product. Generally, the weight ratio of hydrogen to feed coal (anhydrous, ashless basis) is 0.0
3 to 0.08 is sufficient, but it also improves the diffusion of liquid products from coal and the diffusion of hydrogen into coal pores, increases the conversion rate from coal to gasoline fraction, and prevents coking. , it is desirable to supply excess hydrogen. However, this excess hydrogen is separated from the products from the coal and recycled back to the reactor, so as the amount of excess hydrogen increases, the energy and equipment required for separation, circulation, and heating become uneconomical. becomes disadvantageous.

Therefore, the ratio of the amount of coal supplied in step (a) (anhydrous, ashless basis) to the total amount of reacted hydrogen gas supplied in step (i) and step (c) is 10:1 to 2 by weight.
．． Sokudo is in the 3 range, especially 10:1.
A range of 2 to 1.1 is preferred.

In the method of the present invention, the ratio between the amount of reactant hydrogen gas supplied in step (a) and the amount of reactant hydrogen gas fed in step C is the same as that required for hydrogenation in step (b) and (−→ step). It is determined by the amount of hydrogen gas, the amount of excess hydrogen gas in the tank to prevent coking, and the amount of hydrogen residue required to strip the reaction product from the solid phase reaction in step (c), but it is preferable to 2゛1 not 1,20 in ratio
: The range is 1.

According to the coal hydrogenation pyrolysis method of the present invention, a high value-added gasoline fraction can be obtained at a high yield, and the generation of methane gas is suppressed and the production before combustion is increased, so that the reaction The amount of hydrogen for hydrogenation relative to the amount of hydrocarbons produced can be significantly reduced.

In addition, in the method of the present invention, coal refers to anthracite, bituminous coal,
Refers to subbituminous coal, charcoal, lignite, peat, grass charcoal, etc.

In short, the conversion rate from coal to each reaction product is defined by the following equation.

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

Example I Australian lignite was finely pulverized using a free crusher to reduce 150 mesh or less to 83 qb or more, and then pulverized to 1,720 ph in a vacuum dryer.
g, dried at 1.00° C. for 24 hours, and the moisture content was adjusted to about 3.3 parts by weight based on 100 parts by weight of coal. The elemental analysis values of the coal were as shown in Table 1 on an anhydrous basis.

Preheat the first surface pressure cuff 0 Ktq/cnl (l of room temperature hydrogen gas (hydrogen purity 99% or higher) 80 N m”/H to 750°C with an externally heated hydrogen gas preheating tube. 1.9 Nm/H of room temperature oxygen gas of CaG is mixed with the preheated hydrogen gas, and a part of the reaction equivalent of the preheated hydrogen gas is combusted to produce heated hydrogen gas at 1100°C.Meanwhile, 23.
3Kg/H of the finely pulverized dry coal at room temperature is placed in pressure cuff 1 at 9/
Under ctl G, using room temperature hydrogen gas of 3,2 N tn"/H, the coal is conveyed through a coal hopper pipe and jetted and mixed into the heated hydrogen gas stream to heat the coal from room temperature to 750°C. The temperature rises rapidly. The heating rate of the coal at this time is estimated to be approximately 5 x 104 °C/sec. Furthermore, the coal and hydrogen gas mixture is placed in a reaction tube with an inner diameter of 20 mmφ at 75 °C.
Flow at 0°C to carry out the reaction in step (a).

Thereafter, a gas phase and a solid phase are separated in a cyclone separator, and the solid phase is supplied to a fluidized bed reactor. Next, pressure cuff 5
Kg/ciG of room-temperature hydrogen gas 12 N yn'/H was heated to 800°C using an externally heated hydrogen gas preheating tube and supplied to the fluidized bed reactor, and the reaction in step (c) was carried out at 750°C. Let it happen. Solid particles (char) were removed from the fluidized bed reactor to suppress the accumulation of char in the fluidized bed reactor. The reaction gas produced in the fluidized bed reactor is mixed with the reaction gas produced in step (a) separated by the cyclone separator, and passed through a reaction tube with an inner diameter of 60 mm at a temperature of 750°C. A gas phase hydrogenation reaction is carried out. The reaction product from the reaction tube in the above process is rapidly cooled to 380°C in a double-tube quencher, and after separating the entrained char with a char trap, the liquid product is condensed in an indirect water cooler. It was separated from the gas and analyzed separately.

In order to keep the reaction temperature constant in each reaction zone, an electric heater was installed around the reactor, and a hydrogen combustion chamber (a)
(b), H, ni) and the electric heater,
By storing it in a pressure-resistant container with an inner diameter of 500mm, there was no need for a pressure-resistant reactor or the like.

In addition, the reaction pressure is 70 to 9/cA at the outlet of the process reaction tube.
In G, the weight ratio of the total amount of hydrogen used for the reaction to the amount of coal supplied on an anhydrous and ashless basis is 0.41. The reaction hydrogen gas supply ratio in step (a) and step (c) is 6 in molar ratio.
．． The ratio is 8:1. Furthermore, the residence time of the main gas phase from the mixing point of the pulverized coal and heated hydrogen in step (a) through step (b) to the outlet of the reaction tube in step (ii) is 6 seconds, and from the mixing point to ( The average residence time in the same phase from the point of supply of heated hydrogen gas to the fluidized bed reactor to the solid extraction from the fluidized bed reactor in step r) after passing through step O) is 6 minutes. B) Process The residence time of the sub-gas phase up to the outlet of the reaction tube was 25 seconds.

As a result of analysis of the reaction product, the conversion rate of the reaction product from coal on a carbon basis was as shown in Table 2.

Notes on Table 2 x 1) Ethylene is about 5 times as much as ethane.The total value of ethane and ethylene is called ethane.

×2) The material balance of the analysis result is 96i! 102 from the quantity section
Although it was based on weight, the amount for which there was no material balance was taken as liquid hydrocarbon products excluding gasoline fraction.

Examples 2 to 4 Reaction experiments were conducted using the same sample of dry pulverized coal (Australian lignite) used in Example 1 using the apparatus described in Example 1.

Table 3 shows the results obtained by changing the reaction conditions for each example, such as the temperature in the reaction zone, the residence time of the gas phase, and the residence time of the solid phase.

In addition, in order to change the reaction time, the amount of coal supplied, the amount of heated hydrogen gas supplied, and the diameter of the reaction tube were changed appropriately, and the reaction was carried out in Example No. 3 Notes Σ, 3) (a) and (c) steps. Weight ratio of heated hydrogen and supplied coal on an anhydrous and ashless basis ==4) Molar ratio comparison between the amount of reacted hydrogen gas supplied in step (a) and the amount of reacted hydrogen gas supplied in step 09 Comparative Example 1 Strength of Example 1 In the same manner as the zero-thermal hydrogen gas production method, a pressure cuff 2 x9/C=o, 80 N m3/H of preheated hydrogen gas at a temperature of 750°C, and 1. , 9N
m3/H are mixed in the combustion chamber and a portion of the preheated hydrogen gas is combusted to produce heated hydrogen gas at 1100°C. On the other hand, the same pulverized coal (Australian lignite) 24I as in Example 1
Q/H using pressurized hydrogen gas 3.2 Nm3/H,
The coal is conveyed via piping from a hopper, mixed in the heated hydrogen gas stream, and the temperature of the coal is rapidly raised from room temperature to 750°C in a trench. The heating rate of the coal at this time is estimated to be about the same as in Example 1. Further, the mixture of hydrogen gas and coal is passed through a reaction tube having an inner diameter of 60 mm to carry out a reaction at 750°C. The reaction product from the reaction tube was rapidly cooled to 380°C using a double tube type quencher, and the char was separated using a chart lamp.
A similar analysis was performed.

Equipped with an electric heater to maintain the temperature in the reaction zone.
This is the same as in Example 1 in that a pressure-resistant container such as a reaction tube is added to obviate the need for a pressure-resistant container.

The reaction pressure is 70 Kq/cr at the outlet of the reaction tube.
ux G, and the ratio of the total amount of hydrogen used for the reaction to the amount of coal supplied on an anhydrous and ashless basis is a weight ratio of 34. The gas phase residence time from the mixing point of coal and heated hydrogen gas to the outlet of the reaction tube is 6 seconds, and the solid phase residence time in the same reaction zone is approximately 3 seconds.
It was seconds.

According to the analysis results of the reaction product, the conversion rate of the reaction product from coal based on carbon was as shown in Comparative Example j in Table 4.

Comparative Examples 2 and 3 Table 4 shows the results of an experiment conducted in the same manner as in Comparative Example 1 by changing the reaction temperature and the residence time of the gas phase and solid phase.

Table 4 − dawn of Note *3) Same meaning as above.

From the above results, the advantages of the present invention compared to the prior art can be summarized as follows.

(1) The conversion rate from coal to Ganlin fraction increases by about 30 times.

(2) The conversion rate of coal to ethane increases by about 15%.

(3) The total conversion rate from coal is increased by about 20% compared to the conventional technology; 11. Since the increase in fuel oil and gasoline fractions is the main cause and the conversion rate to methane does not increase significantly, the amount of hydrogen consumed for reaction with the generated hydrocarbon compounds is small, and the hydrogen production cost can be reduced.

Patent applicant: Asahi Kasei Industries, Ltd. Agent Akira Agata

Claims (1)

[Claims] 1. A step in which coal is liquefied and gasified by heat treatment in the presence of hydrogen, (a) fine coal powder is jetted into a heated hydrogen gas stream to rapidly heat and react; (B) A step of separating the reaction product obtained by the above reaction into a gas phase and a solid phase, C→ A step of causing the solid phase separated in step (1) to undergo a contact reaction with hot hydrogen gas at the edge of the blade) (b) A step of roughly hydrogenating the gaseous phase separated in step e-> and the gaseous product obtained in step e->, and (e) a step of rapidly cooling the reaction product obtained in step). , a coal hydrogenation pyrolysis method characterized by being carried out continuously. 2. The method according to claim 1, wherein the reaction temperature in steps (a), (b), (c), and (i) is 550 to 900°C. The method according to claim 1, wherein the pressure is K9/ca (gauge pressure). 4 (a) The heating rate of coal in the process is 1000℃/
The method according to claim 1, which is at least 1 second
2. The method according to claim 1, wherein the ratio of the total reaction hydrogen gas supply amount in steps (a) and (c) is in the range of 10:1 to 2:3 by weight. 6 The ratio of the amount of reactive hydrogen gas supplied in step (a) to the amount of reactive hydrogen gas supplied in step e is 21 in terms of molar ratio.
A method as claimed in claim 1 in the range from 20.1 to 20.1.