JPS61176689A - Hydrogenative liquefaction of coal - Google Patents

Abstract

PURPOSE:To improve the recovery of oil without increasing the consumption of hydrogen, by blowing a hydrogen-containing gas obtained from the hydrogenation reaction product to the first hydrogenation reaction column, and carrying out the hydrogenation under a specific condition while stripping the light oil component from the solvent. CONSTITUTION:A slurry mixture of coal powder and solvent is preheated and supplied to a plurality of hydrogenation reaction columns connected in series to effect the hydro-cracking. In the above process, the gaseous product is separated from the hydrogenation reaction product in each reaction column, the light oil component and water are removed from the gaseous product, and the obtained hydrogen-containing gas is introduced to the bottom of at least the first hydrogenation reaction column. The hydrogenation is carried out while stripping the light oil component in the solvent in a manner that the weight ratio of the fraction having a boiling point of 300-420 deg.C (reduced to normal pressure) in the solvent existing in the reaction column to the sum of the coal and the fraction having a boiling point of >=420 deg.C in the slurry mixture becomes 0.20-1.20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for hydrogenating and liquefying coal, and in particular, it significantly increases the oil recovery rate without making hydrogenation reaction conditions particularly severe and without increasing hydrogen consumption. The present invention relates to a hydrogenation and liquefaction method that can be used for hydrogenation and liquefaction.

Hydrogenation and liquefaction is one of the methods for decomposing coal and converting it into a useful liquid substance. In this method, pre-pulverized coal is mixed with a slurry-forming solvent, or after mixing with a solvent, the coal is crushed into a slurry, and then sent to a hydrogenation reaction tower, where the coal is hydrogenolyzed at high temperature under pressure of hydrogen gas. A typical method is shown in FIG. That is, in FIG. 1, coal powder is mixed with a slurry-forming solvent to form a slurry, and then sent to a preheater 1 by a slurry pump P, where it is heated to a predetermined temperature. In this case, a suitable hydrogenation catalyst may be added during the slurry preparation stage, and high-pressure hydrogen for hydrogenation is usually blown into the slurry feed pipe immediately before the preheater l. The preheated slurry and hydrogen gas are air, air, and solid.
The phase mixture passes through the first hydrogenation reaction tower 2a, the second hydrogenation reaction tower 2b, and the third hydrogenation reaction tower 2C and undergoes a hydrogenolysis reaction sequentially. It is sent from the addition reaction tower 2C to the gas-liquid separator 3. Internally, three hydrogenation reaction towers 2a
-2C are shown arranged in series, but the number of hydrogenation reaction columns may be two or less, or four or more may be arranged in series. In the gas-liquid separator 3, heavy components including ash (including inorganic substances and catalysts in coal) and SRC are discharged as liquid substances or are further sent to a secondary hydrogenation process, and light oil, water and Gas components including unreacted hydrogen gas are condensed with water and light oil in the condenser 4, and then separated in the Yuki separator 5 to recover light oil as a product, while the gas components separated in the condenser 4 are Expelled outside. The gas discharged outside the system contains a large amount of unconsumed hydrogen during the hydrogen cracking process (hydrogen content is approximately 60% or more).
It is also considered that after removing part or all of 1g'4 of Co, CO2, C+-C3f) hydrocarbon water, it can be recycled and used as hydrogen for hydrogenolysis. In addition, the hydrogenation reaction tower 2a~
The decomposition reaction in 2C is an exothermic reaction, and the reaction temperature may become abnormally high depending on the slurry concentration and the type of coal.
~2C may be blown in as a cooling gas from the side wall.

Furthermore, a method is also known in which a portion of the heavy components separated in the gas-liquid separator 3 is returned as a slurry-forming solvent.

By the way, in the conventional hydrogenation and liquefaction process as described above, in order to ensure safe and stable operation, operation is carried out at mild pressure and temperature and under conditions that suppress hydrogen consumption as much as possible. In this case, the proportion of heavy components (SRC) in the liquefied product was high and the yield of distillate oil was low. In order to increase the yield of distillate oil, it is necessary to make the reaction conditions more severe by further raising the temperature and pressure as well as increasing the amount of catalyst, but in this case the heat generated during hydrogenolysis becomes significant and the temperature Control becomes difficult, problems tend to occur in operational stability and safety, the decomposition of distillate oil becomes significant, the amount of low-carbon gas components increases, and the overall recovery rate of distillate oil does not improve much.

On the other hand, in hydrogenation and liquefaction reactions, it has been confirmed that the distillate oil recovery rate varies significantly depending on the type of slurrying solvent, and heavy ones (3 to 4 rings or more) are excellent as slurrying solvents. Demonstrate performance. For this reason, operations are managed to use as heavy a slurry solvent as possible, but heavy solvents have a high viscosity, so the slurry mixed with coal powder also becomes highly viscous and has poor fluidity. However, in actual operation, a considerable amount of a light solvent is used in addition to a heavy solvent to adjust the viscosity of the slurry. The combined use of such light solvents is extremely effective from the standpoint of slurry preparation and transportation, but on the other hand, it is clearly negative in terms of hydrogenation reaction efficiency. In other words, as mentioned above, heavy solvents are preferable in order to increase the hydrogenolysis efficiency, and when a light solvent is used in combination as a slurrying solvent, the reaction efficiency (NJ also increases the distillate oil recovery rate) depending on the usage ratio. decreases. Furthermore, the reaction efficiency decreases due to the dilution of the heavy solvent, and furthermore, in the hydrogenation reaction tower, the concentration of the heavy oil decreases further due to the production and increase in the amount of light oil produced by hydrogenolysis. This is thought to have an adverse effect on the reaction efficiency and hinder the increase in reaction efficiency.

In addition, a sufficient amount of solvent is required in the preheating stage to more completely dissolve the coal powder and to suppress the polycondensation reaction, but in the hydrogenolysis stage the solvent is significantly diluted by the lightening reaction. It is preferable to keep the amount of the slurry-forming solvent to a minimum.If we compare the preheating stage and the hydrogenation reaction stage, the appropriate amount of solvent is inversely proportional.
Conventionally, the amount of solvent has been determined based on a balance between the two, so the concentration of the solvent during the hydrogenation reaction has to be considerably thinner than the optimum concentration.

As described above, conventional hydrogenation and liquefaction methods have problems in that the slurry solvent becomes heavy and highly concentrated in the hydrogenation reaction tower, and it is difficult to increase the recovery rate of distillate oil to a satisfactory level. could not.

The present inventors focused on these circumstances, and established a technology that can increase the concentration of the slurry and increase the weight of the solvent in the hydrogenation reaction stage, thereby increasing the recovery rate of distillate oil.
The present invention was completed as a result of such research, and its configuration consists of preheating a mixed slurry of coal powder and a solvent to multiple hydrogenation reaction towers connected in series. In a coal hydrogenation and liquefaction method that performs feed hydrocracking, a gaseous product is separated from the hydrogenation reaction product in each water mixing reaction tower, and the gaseous product is obtained by removing light oil and moisture from the gaseous product. Hydrogen-containing gas is blown into at least the bottom of the hydrogenation reaction tower in the first stage, and a fraction with a boiling point (normal pressure equivalent) of 300 to 420°C in the solvent present in the first reaction tower is added to the coal in the mixed slurry. (based on anhydrous ash-free coal) and the distillate with a boiling point (normal pressure conversion 3i) of 420°C or higher, the light oil content in the solvent is stripped to a weight ratio of 0.20 to 1.20. The gist of this method is that it performs hanging hydrogenation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and effects of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a schematic flow diagram showing an embodiment of the present invention, and the basic configuration is substantially the same as the conventional example shown in FIG. However, in this example, in addition to a heavy solvent (3 to 4 rings or more), a considerable amount of a light solvent is used as the slurry-forming solvent to reduce the viscosity of the slurry. A gas-liquid separator 3, a condensation I 14, and an oil-water separator 5 are installed in the hydrogenation reaction towers 2a and 2.
The reactant discharge line b is also provided with gas-liquid separators 3a, 3b, condensers 4a, 4b, and oil-water separators 5a, 5b. The hydrogen-containing gas (hereinafter sometimes referred to as circulating gas) Ga and Gb from which oil and moisture have been removed is transferred to a gas circulation pump 8.
a, 8b and heaters 9a, 9b to each hydrogenation reaction tower 2.
This differs from the example shown in FIG. 1 in that the air is blown from the bottom of points a and 2b, and this is the most distinctive feature of the present invention. That is, the second
As shown in the figure, hydrogen-containing gas is separated from the gasified products discharged from each hydrogenation reaction tower 2a, 2b, and a heater 9a
, 9b and then blowing from the bottom of each hydrogenation reaction tower 2a, 2b, the low clean point component in each hydrogenation reaction tower 2a, 2b quickly rises in the reaction tower 2a, 2b together with the circulating gas. , the solvent component of each reaction column is substantially heavier.

As a result, the hydrogenation reaction efficiency is significantly improved without making the hydrogenation conditions in each hydrogenation reaction tower 2a, 2b particularly strict, and the recovery rate of liquefied oil can be significantly increased. Moreover, in a conventional hydrogenation reaction tower, along with unliquefied coal and high-boiling components, the light solvent contained in the slurry solvent and the light oil produced by hydrogenolysis rise inside the tower at almost the same speed. It undergoes hydrogenolysis from the inside and further produces a gas component with a low carbon content (C
However, in this example, as mentioned above, the light oil passes through the hydrogenation treatment atmosphere at high speed together with the circulating gas, and each water Gas and liquid are separated in the reactant discharge line of the addition reaction tower and extracted from the system, which suppresses the formation of low-molecular substances, and together with the improvement of hydrogen cracking efficiency by making the solvent heavier, the recovery rate of light oil is greatly increased. can be increased. Furthermore, since the solvent can be made heavier in the hydrogenation reaction tower as described above, a considerably large amount of light solvent can be blended in the slurry preparation stage, which improves the handling of slurry preparation and pipeline transportation. In addition, the coal powder can be melted efficiently in a short time by the preheater 1.

The liquid separated by the gas-liquid separators 3a and 3b contains a large amount of undecomposed coal and heavy oil, so it is sequentially sent to the downstream hydrogenation reaction tower for hydrogenolysis, and the final The liquid separated by the gas-liquid separator 3 provided in the hydrogenation reaction tower 2C is discharged as heavy oil (SRC) through a deashing device 6, or is further sent to a secondary hydrogenation step. Also, each condenser 4a, 4b
-1? After being condensed, the light oil separated in the oil-water separators 5a and 5b is combined with the light oil extracted from the final gas-liquid separator 3 through the condenser 4 and the oil-water separator 5, or is separately processed as a product. taken out. Also, the gas-liquid separator 3a
, 3b is adjusted by controlling the degree of suction of the gas circulation pumps 8a, 8b. Furthermore, in FIG. 2, the product discharged from the final stage hydrogenation reaction tower 2C is separated into gas and liquid, and then passed through the condenser 4.
The hydrogen-containing gas Gc from which light oil and moisture have been removed is also blown into the hydrogenation reaction tower 2C from the bottom.

Although the hydrogenation reaction rate in the hydrogenation reaction tower 2C can also be increased, it is also possible to omit the blowing of circulating gas into this part. The reason for this is that in equipment like the one shown in the figure, in which multiple hydrogenation reaction towers are arranged in series, the hydrogenolysis of coal has progressed considerably by the time it reaches the final stage hydrogenation reaction tower, and This is because even if the reaction efficiency in the addition reaction tower is increased, it does not contribute much to improving the oil recovery rate of the entire equipment. However, it is clear that if the gas blowing treatment as shown in the figure is also applied to the final stage hydrogenation reaction tower 2C, the oil recovery rate can be improved to a certain degree.

By the way, as mentioned above, the hydrogenation reaction is an exothermic reaction, and depending on the heating temperature of the circulating gas blown in from the bottom of the tower, there is a risk that the temperature inside the tower will rise too much. Similarly, it is also possible to adjust the reaction temperature by blowing the circulating gas before preheating as a cooling gas, for example, from the side of each reaction tower. In this case, taking into account that the reaction temperature may drop too much, it is also effective to blow heated circulating gas into each group from the side.

As mentioned above, the circulating gases Ga, Gb, and Gc contain a large amount of hydrogen, so even if they are effectively consumed as a hydrogen source for the reduction reaction, they do not inhibit the hydrogen cracking reaction. As shown by the chain line in FIG. 2, it is also possible to return and use a portion of the heavy oil and light oil that are continuously extracted from the equipment as a slurrying solvent.

In the internal explanation, an example was shown in which three hydrogenation reaction towers were connected in series, but the number of combinations of hydrogenation reaction towers is not particularly limited, and two or four or more hydrogenation reaction towers may be arranged. Of course, there is no problem.Also, the figure shows an example in which the hydrogen-containing gas separated and extracted in the reactant discharge line of each hydrogenation reaction tower is blown into the bottom of the hydrogenation reaction tower, but there are other hydrogenation reaction towers. It is also possible to blow in the hydrogen-containing gas extracted from the reactant discharge line from the bottom of the hydrogenation reaction tower on the upstream side.

A more preferable method for blowing the circulating gas is to maximize the amount of circulating gas blown into the first hydrogenation reaction tower 2a, where hydrogenation efficiency needs to be maximized, and to blow the circulating gas into the second hydrogenation reaction tower 2a, which needs to maximize the hydrogenation efficiency. The amount of circulating gas blown into the third hydrogenation reaction tower is gradually reduced. For example, the amount of circulating gas blown into the third hydrogenation reaction tower is decreased in series. The ratio is as follows.

(Hereinafter in the margin) (Hereinafter in the margin) There are no particular restrictions on the hydrogenation reaction conditions, and conventional hydrogenation and liquefaction conditions can be applied almost as they are, but the most typical conditions are as follows. be.

Reaction temperature: 400-470°C (more preferably 430-470°C
450℃) Reaction pressure: 50 to 300 kg/cm2 G (more preferably 150 to 200 kg/cm2 G) Catalyst:
Weight of iron and sulfur catalyst solvent/weight of coal (e+af: based on anhydrous ash-free coal) ~
1.7 to 3.0 (more preferably 2.Q to 2.5) Heavy solvent: B, P, high boiling point hydrocarbon of about 180°C or higher By the way, the above-mentioned stripping effect by circulation of hydrogen-containing gas is effective. According to various experiments conducted to clarify the conditions for this effect, (A) The solvent present in the reaction tower has a boiling point of 300 to 42
Fraction (X) at 0°C (normal pressure equivalent) and (B) coal in the mixed slurry supplied to the hydrogenation reaction tower (based on anhydrous ash-free coal)
and the fraction with a boiling point of 420°C (converted to normal pressure) or higher (Y
It has been found that the weight ratio (X/Y) of ) is an important factor that influences the stripping effect and the situation inside the reaction column. In other words, by controlling the circulating supply of hydrogen-containing gas with a focus on adjusting (X/Y) within the range of 0.20 to 1.2.0, more reliably within the range of 0.30 to 0.80, this It was confirmed that the object of the invention could be effectively achieved. The reason for setting these numerical ranges will be explained below.

When hydrogen gas is circulated and supplied from the bottom of the hydrogenation reaction tower,
Low-boiling components in the liquid phase within the reaction tower are quickly discharged outside the tower due to the stripping effect, promoting heavier solvents. As already clarified, the degree of heavyization varies considerably depending on the temperature and pressure of the hydrogenation reaction, the type of slurry forming solvent, and the slurry concentration. It is extremely difficult to regulate accurately. Therefore, from the perspective of improving hydrogen cracking efficiency, that is, improving oil recovery rate, we need to determine the minimum degree of heaviness necessary to achieve this objective, and the maximum degree that allows the hydrogenation reaction to proceed without causing coking. In order to clarify the extent of the increase in weight, the correlation between the raw material slurry and the components in the column during gas circulation treatment was investigated. In other words, from a large number of experiments including preliminary experiments, we found: ■ Experimental data that showed the effectiveness of circulating gas injection (light treatment example), and ■ Using the bottom recycling method in combination with sufficient circulating gas injection. We selected experimental data (example of heavy processing) in which it is predicted that coking may occur if the injection continues any longer than this, and investigated the composition of each raw material slurry and the composition of the components in the column after the circulating gas injection treatment. The results shown in FIGS. 3(A), (B) and 4(A), (B) were obtained.

From these experimental data, the degree of heavyization during light treatment and heavy treatment can be determined by (A) the amount of light red medium oil with a boiling point of 300 to 420°C (X) among the components in the column after treatment; CB)
Comparing the ratio (X/Y) of the total sum (Y) of carbonaceous materials and heavy oil with a boiling point of 420°C or higher in the raw material slurry, Figure 3 (A) and (B) show that during light processing, As is clear, X/Y=37/33=1.12, while during heavy processing, as is clear from FIGS. 4(A) and (B), X/Y=19/64=0. It becomes 30.

In other words, from these calculated values, the value of the (X/Y) ratio that achieves the purpose of making the solvent heavier is 1.12, but depending on the type of coal or slurry solvent, hydrogenation conditions, etc. It is thought that this value can be increased to about 1.20.

On the other hand, the upper limit of the weight of the solvent (i.e., the state 1 fB just before it becomes too heavy and causes coking in the column) is shown in Figure 4 above (
It can be predicted based on the (X/Y) values during heavy processing shown in A) and (B), and if the hydrogenation conditions etc. are properly adjusted, the upper limit of heavy processing will be (X/Y). It is thought that it can be reduced to about 0.20. From these results 0.20
≦(X/Y)≦1. ! A range of 2 was derived, but when we also took into account many other experimental data to determine the range where the weighting effect could be more reliably exerted, we found that (X/
y)=0.30 to 0.80.

In the present invention, the temperature and injection amount of the circulating gas G may be arbitrarily adjusted according to the types of coal and slurry solvent, slurry concentration, hydrogenation conditions, etc., but as the most general standard, the injection amount is The actual flow rate under reaction conditions per ton of solvent in the slurry is approximately 60 m'' or less (more preferably l
0 to 45rr1''), and the amount of injection exceeds the above range.

It should be noted that if the heating temperature of the circulating gas is too high, the solvent in the column may transfer excessively to the gas phase and cause coking.

By carrying out the method of the present invention under the above conditions, it was possible to significantly increase the recovery rate of distillate oil by hydrogenation and liquefaction treatment, as shown below. That is, in Table 1 and Figure 5 below, an experimental hydrogenation reactor consisting of three reaction towers was used, reaction temperature: 430°C, pressure crab 150kg/cm.
2G, solvent weight/coal weight (■af): 2.5, catalyst: iron/sulfur system, amount of hydrogen supplied: 10% by weight (■af)
Gas returned to the C1 reaction tower: 430°C, 26x3/1 ton of solvent (separation ratio - 1st reaction tower: 9 parts, 2nd reaction tower = 3 parts, 3rd reaction tower: 2 parts), composition (H2 :84.2%, Co
-1-CO2: 8.8%, CHs: 4.3%, others = 2. The yield of each decomposition product per supplied coal (based on anhydrous and ash-free coal) when hydrogenated and liquefied under conditions of It is something that

(Left below) Table 1 As is clear from the results in Table 1 and Figure 5, gas stripping increases the recovery rate of distillate by more than 1.5 times compared to the conventional method. I can confirm that I get it.

FIG. 6 shows another embodiment of the present invention, which is substantially different from the example shown in FIG. 2 above, except that gas-liquid separation is performed at the top of the hydrogenation reaction towers 2a and 2b. No, that is, each hydrogenation reaction tower 2a in FIG.

Separate gas-liquid separation sections 3a and 3b were provided on the top side of 2b, but
In this example, gas-liquid separation sections 3a and 3b are integrally provided at the top of each hydrogenation reaction tower 2a and 2b, and the other configurations and possible design changes are exactly the same as in Fig. 2. Just understand.

The present invention is constructed as described above, and its effects can be summarized as follows.

(1) The light content in the slurrying solvent and the light oil produced by hydrogenolysis of coal quickly rise in the reaction tower together with the gas, so the slurrying solvent in the hydrogenation reaction tower becomes significantly heavier. The hydrogen cracking efficiency can be sufficiently increased even under relatively mild conditions, and since the light oil quickly rises in the reaction tower, it does not undergo further hydrogen cracking and becomes gasified, and these are synergistic. The recovery rate of oil, especially distillate oil, can be greatly increased.

(2) As mentioned above, the slurry-forming solvent can be made sufficiently heavy in the hydrogenation reaction tower, so even if a considerable amount of light solvent is used in the slurry preparation process, the hydrogenation reaction efficiency may decrease. Therefore, slurry preparation and pipeline transportation of the slurry can be carried out with good handling properties.

(3) Since the circulating gas contains a large amount of hydrogen gas, the amount of newly blown hydrogen gas can be reduced by circulating the gas.

[Brief explanation of drawings]

Fig. 1 is a schematic flow diagram showing a known coal hydrogenation and liquefaction method, Fig. 2 is a schematic flow chart showing an embodiment of the present invention, and Fig. 3 (A
), (B) and Figures 4 (A) and (B) are graphs showing experimental data conducted to determine the suitable range for increasing weight by circulating gas injection, and Figure 5 is a graph showing the presence and absence of circulating gas injection. FIG. 6 is a schematic flow diagram showing another embodiment of the present invention. l... Preheater 2a, 2b, 2c... Hydrogenation reaction tower 3.3a, 3b... Gas-liquid separator 4.4a, 4b... Condenser 5.5a, 5b... Oil-water separation Applicants: Kobe Steel, Ltd. Mitsubishi Chemical Industries, Ltd. Idemitsu Kosan Co., Ltd. Asia Oil Co., Ltd.

Claims (3)

[Claims] (1) In a coal hydrogenation and liquefaction method in which a mixed slurry of coal powder and a solvent is preheated and sent to a plurality of hydrogenation reaction towers connected in series for hydrogenolysis, the hydrogenation reaction is performed in each hydrogenation reaction tower. A gaseous product is separated from the product, and a hydrogen-containing gas obtained by removing light oil and water from the gaseous product is blown into the bottom of the hydrogenation reaction tower at least in the first stage and into the reaction tower. Boiling point in existing solvent (converted to normal pressure) 300-42
The weight ratio of the fraction at 0° C. to the total amount of coal (based on anhydrous ash-free coal) and the fraction having a boiling point (converted to normal pressure) of 420° C. or higher in the mixed slurry is 0.20 to 1.20. A method for hydrogenating and liquefying coal, characterized by carrying out hydrogenation while stripping light oil in a solvent so that the following is achieved. (2) The hydrogenation and liquefaction method according to claim 1, wherein the gaseous product is separated from the hydrogenation reaction product at the top of each hydrogenation reaction tower. (3) The hydrogenation and liquefaction method according to claim 1, wherein a gaseous product is separated from the hydrogenation reaction product outside each hydrogenation reaction tower.