JPH0141195B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reforming coal containing alkaline earth metals and alkali metals.

Conventionally, various coal reforming methods have been known in which pulverized coal is mixed with a hydrocarbon solvent to form a slurry, and the slurry is reacted at high temperature and pressure to reduce the molecular weight of coal. Among these, the most representative one was
The Bergius method was industrialized on a large scale in Germany in the 1930s, and more recently, the method of Hydrocarbon Research Inc. disclosed in U.S. Patent No. 2987465, and U.S. Patent No. 3341447 and 3808119 and others, U.S. Gulf Corporation's method, U.S. Patent No. 3488279
Esso Research & Engineering (U.S.)
Engineering)'s method, etc. These coal reforming methods mainly use bituminous coal, sub-bituminous coal, lignite, and lignites with particularly low carbonization degrees as raw materials, and use a hydrocarbon solvent, hydrogen, carbon monoxide,
Coal is reduced to a lower molecular weight under high temperature and pressure while using a reducing gas such as a carbon monoxide-steam mixture gas.
It purifies, liquefies, or reforms coal by causing various reactions such as deoxygenation, hydrogenation, deflow, and denitrification, and converts low-grade coal into fuel that is liquid or solid at room temperature and carbon material for metallurgy. This is an extremely useful method for obtaining various high-grade carbon materials such as carbon materials.

However, in these methods, coal with a high content of alkaline earth metals and alkali metals is used as the raw material coal, for example, the total content of these metals is 0.2% (wt%, same hereinafter) or more on a dry coal basis. If used, salts mainly consisting of carbonates of alkaline earth metals and alkali metals will precipitate during the reforming reaction, and after a long coal reforming reaction operation, it will cause damage to the reactor and other parts. It accumulates in various parts of the equipment and interferes with smooth continuous operation.
This has become one of the major problems in coal reforming technology.

In view of these circumstances, the present inventors have aimed to solve the problem of accumulation of alkaline earth metals and alkali metal salts in reactors, etc. in coal reforming, and to enable smooth continuous operation in coal reforming. As a result of extensive research, we discovered that by mixing inorganic powder and granules with a slurry of pulverized raw coal and causing a reaction, salts of alkaline earth metals and alkali metals were precipitated on the granules. The present inventors have discovered that the objective can be achieved by appropriately removing the precipitated and adhered powder to the outside of the reaction system, and have completed the present invention.

That is, in the present invention, pulverized coal containing alkaline earth metals and alkali metals is mixed with a hydrocarbon solvent to form a slurry, and the resulting slurry is
When modifying coal by reacting it under high temperature and high pressure of 50 to 700 atm at ℃, inorganic powder and granules that become precipitation nuclei are added and mixed to the slurry, and the alkaline earths liberated during the coal modification reaction are An alkaline earth metal, characterized in that the metal or alkali metal is precipitated as a salt on the surface of the granular material, and the granular material is sequentially or continuously removed from the system in a reaction step or a post-reaction step; The present invention provides a method for reforming coal containing alkali metals. According to the method of the present invention, during the coal reforming reaction, alkaline earth metals and alkali metal salts are selectively formed on the surface of the inorganic powder mixed in the slurry of crushed raw coal as a core. ,
In addition, since the salts precipitate faster than when inorganic powder is not used, by removing the salts from the system during or after the reaction, it is possible to prevent the salts from adhering to or depositing on the reactor or other equipment. can be prevented, and coal reforming can be performed with excellent smooth continuous operation.

Next, the present invention will be explained using the accompanying drawings.

In the drawings, FIG. 1 and FIG. 2 are each a schematic flow sheet showing a specific example of the method of the present invention.

In the specific example shown in FIG.
Mesh, preferably raw coal pulverized to a particle size finer than 200 mesh, a hydrocarbon solvent with a boiling point of about 150 to 500°C (normal pressure equivalent), inorganic powder and, if desired, an appropriate material such as iron-sulfur type. A slurry is prepared by stirring the catalyst in a slurry preparation device 1. The obtained slurry is sent to a preheater 3 by a slurry pump 2 and is preheated. As desired,
A reducing gas such as hydrogen, carbon monoxide or a carbon monoxide-steam mixture gas is added before or after preheating, preferably before preheating. Next, the preheated slurry is introduced into the reactor 4, where it is allowed to stay for a predetermined period of time, and subjected to a coal reforming reaction at a high temperature and high pressure, for example, at 300 to 500°C and 50 to 700 atmospheres. During this time, the alkaline earth metals and alkali metals in the coal form the core of the inorganic powder mixed in the slurry, and selectively and quickly precipitate and adhere to the surface as salts mainly composed of carbonates. This prevents the salts from precipitating and depositing on the wall surface of the reactor. Further, the entire reaction mixture containing the inorganic powder is led to the reactor 4' and subjected to a coal reforming reaction, and the inorganic powder is exposed to the alkaline earth in the coal on its surface as well as in the reactor 4. Precipitating and adhering salts of similar metals and alkali metals to prevent the salts from precipitating and depositing on the walls of the reactor. In this way, most of the salts of alkaline earth metals and alkali metals generated in the reforming reaction precipitate and adhere to the surface of the inorganic powder, so they can be used not only in the reactor but also in various subsequent processes. Deposition of the salts on equipment is prevented. The reaction mixture containing the inorganic powder is then led to a gas-liquid separator 5, where light gas products are separated, and further passed through a pressure reducing valve 6.
After being flashed, it is led to the gas-liquid separator 7,
Here, a portion of the light oil product and the medium oil product are separated. The inorganic powder and granules together with the remaining reaction mixture are led to a gas-liquid separator 9 via a pressure reducing valve 8, where light and medium oil products are further separated.
Then, it is distilled in a distillation column 10 and led to a deasher 11. In the deasher 11, a heavy hydrocarbon product, which is one of the target coal reforming products, is separated, and inorganic powder and granules are removed from the system together with ash residue derived from raw coal. The oil products separated from the gas-liquid separators 7 and 9 are separated into target light oil products and medium oil products in the distillation column 12, and the medium oil products are separated in the distillation column 10. Combined with quality oil products. If desired, a portion of the medium oil product is recycled to the slurry preparer 1 as a solvent for slurry preparation. By repeating this cycle, smooth continuous operation of coal reforming can be performed while preventing alkaline earth metals and alkali metal salts from accumulating in the reactor and other equipment.

In the specific example shown in FIG. 2, the reactor 4 is filled with inorganic powder P in advance, the pulverized coal prepared in the slurry preparation device 1, a hydrocarbon solvent, and a catalyst are added if desired. The slurry is sent to a preheater 3 by a slurry pump 2.
The slurry is mixed with a reducing gas before being sent to the preheater 3. The preheated slurry is introduced into the reactor 4, mixed with inorganic powder and granules that have been filled in advance, and subjected to a coal reforming reaction while suspended in the slurry. During this period, the alkaline earth metals and alkali metals in the coal form the core of the inorganic powder and granules, and selectively and quickly precipitate and adhere to the surface as salts mainly composed of carbonates. The salts are prevented from precipitating and depositing on the wall surface of the reactor. The powder and granules adhering to the salts settle to the bottom of the reactor.
145405 and JP-A-51-145406, etc., it is continuously extracted from the reactor system. At this time, by making the amount of extraction per unit time approximately equal to the amount of precipitation per unit time, even after all the inorganic powder filled at the start of operation has been discharged, the ash derived from the coking coal can be removed. The crystals and alkaline earth and alkali metal salts that have grown to an appropriate size as cores work in the same way as the powder filled at the start of operation. Therefore, most of the salts of alkaline earth metals and alkali metals that are further generated as a result of the reforming reaction precipitate and adhere to the newly formed powder surface, so they are not only used in the reactor but also in subsequent steps. Deposition of the salts on various devices can be continuously prevented. On the other hand, the reaction mixture is further led to the reactor 4', subjected to a coal reforming reaction, and thereafter treated in the same manner as in FIG.

Thus, in the method of the present invention, the type of hydrocarbon solvent used, the catalyst, the presence or absence of reducing gas,
Modification reaction conditions etc. are not particularly limited.

The raw material coal may be any one containing alkaline earth metals or alkali metals, but the method of the present invention is particularly useful when the total content of these is based on dry coal.
It shows its excellent effect on substances with a concentration of 0.2% or more. In addition, if the oxygen content of raw coal is 12% or more on an ashless dry coal basis, it will react with carbon in the coal to generate CO ₂ and easily create carbonates of alkaline earth metals and alkali metals. It also exhibits excellent effects on such coal.

Examples of the inorganic powder to be used include ash in coal separated in the deashing step after the coal reforming reaction, calcium carbonate or an inorganic substance containing this, and magnesium carbonate or an inorganic substance containing this. The particle size of these particles is finer than 9 mesh, and the particles are suspended in the slurry, and alkaline earth metals and alkali metal salts are precipitated on the surface, and after adhering, they settle, so that they will not flow out of the system. This is preferable because it facilitates extraction.

The granular material may be mixed with raw coal etc. in a slurry preparation device and continuously mixed into the reaction system, or may be directly supplied to the reactor, or a combination of these may be used. Furthermore, as in the method shown in FIG. 2, the powder may be supplied only at the start of operation. The mixing ratio of the granular material to the slurry can be appropriately selected depending on various process conditions and the content of alkaline earth metals and alkali metals in the raw coal, but in general, 100 weight of pulverized raw material coal based on dry coal is used. It is desirable to set it as 10-40 parts by weight.

In addition, as shown in Figure 1, inorganic powder particles on which alkaline earth metals and alkali metal salts have precipitated and adhered are continuously removed from the system in the product separation process after the reaction. Also, as shown in FIG. 2, the reaction may be carried out immediately after the reaction step, sequentially or continuously, or these may be carried out in combination. When removing from the reaction process, in addition to the methods described above, the method disclosed in Japanese Patent Publication No. 52-145404 can be employed.

Next, the present invention will be explained in more detail with reference to Examples.

Example Using the method shown in Figure 2, using Australian lignite having the analysis values shown in Table 1, a continuous reforming reaction was carried out without pre-filling the reactor with inorganic powder. .

Table 1 (Raw coal composition) (Weight %) C 62.6 H 4.3 N 0.7 S 0.5 O 19.8 Ash 4.0 Moisture 8.1 Dry coal base Alkaline earth metal, alkali metal content (Metal) (Weight %) Ca 0.89 Mg 0.43 Na 0.14 K 0.006 Fe 0.21 Si 0.26 Al 0.006 Raw coal is ground to a particle size finer than 200 mesh, and a hydrocarbon solvent (creosote oil, feeding rate: 25 Kg/hour), iron oxide and sulfur ( Fe/S atomic ratio: 1.0 to 1.5) was mixed to prepare a slurry, hydrogen gas was added (supply rate: 0.6 kg/hour), and the slurry was preheated to about 430°C and about 150 atm. The reaction was carried out continuously below. The internal dimensions of the reactor (total of 4 and 4') are: height/inner diameter (L/D) ratio 20, volume of mixture in the reactor 30 (apparent reaction time approximately 1.0 hour)
It was hot. Under similar reaction conditions (however, the creosote oil was recovered and reused), continuous operation time was 10
hours, 20 hours, 30 hours, 40 hours, 50 hours and 60
For each case of time, the reaction was carried out repeatedly, and after each reaction, the amount of precipitation and deposition of alkaline earth metals and alkali metal salts deposited and attached to the reactor wall and other equipment walls, etc. was measured against the continuous operation time. The graph shown in the attached FIG. 3 was obtained. Next, before the start of operation, the alkaline earth metals in the coal, such as calcium carbonate, magnesium carbonate, dolomite, sodium chloride, and sodium carbonate obtained from the reactor wall etc. in the above reaction, are prepared in the form of inorganic powder and granules. A reactor was filled with 3 kg of inorganic substances produced from alkali metals, and precipitates consisting of ash in coal such as quartz and iron sulfide whose particle size was adjusted to 30 to 50 mesh, and the reaction was carried out under the same reaction conditions as above. The coal reforming reaction was carried out repeatedly at continuous operation times of 11.5 hours, 27 hours, and 50 hours, while extracting the powder by appropriately extracting the reaction mixture inside the reactor. In this case, the amount of salts deposited and deposited on the reactor wall etc. is plotted against the continuous operation time.
A graph shown in the attached FIG. 4 was obtained.

In both the graphs of FIG. 3 and FIG. 4, the vertical axis shows the weight of precipitate collected from the wall of the reactor after the end of continuous operation, and the horizontal axis shows the continuous operation time. Third
As is clear from comparing the results in Figure 4 (without using inorganic powder or granule) and Figure 4 (using inorganic powder or granule),
When inorganic powder is not used, carbonates of alkaline earth metals and alkali metals precipitate on the reactor walls more quickly than when inorganic powder is used, but when inorganic powder is used, this is selectively deposited. Because it adheres to the powder and granules, the amount of deposits on reactors and other equipment is greatly reduced.
Smooth continuous operation of coal reforming becomes possible.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic flow sheets showing specific examples of the method of the present invention, and FIGS. 3 and 4 show precipitation of alkaline earth metals and alkali metal salts in the reforming reaction, respectively. It is a graph showing the relationship between object weight and continuous operation time. The main symbols in the drawings mean the following: 1
...Slurry preparer, 4 and 4'...Reactor,
5, 7 and 9...Separator, 11...Deasher.

Claims (1)

[Claims] 1. A pulverized coal containing an alkaline earth metal or an alkali metal is mixed with a hydrocarbon solvent to form a slurry,
When reforming coal by reacting the obtained slurry at high temperatures and pressures of 300 to 500 degrees Celsius and 50 to 700 atmospheres,
Adding inorganic powder to the slurry to serve as precipitation nuclei,
The alkaline earth metals and alkali metals liberated during the coal reforming reaction are precipitated as salts on the surface of the granules, and the granules are heated sequentially or continuously in the reaction process or post-reaction process. A method for reforming coal containing alkaline earth metals and alkali metals, which method comprises removing alkaline earth metals and alkali metals from the system. 2. The reforming method according to item 1 above, wherein the granular material is ash in coal. 3. The modification method according to item 1 above, wherein the granular material is silica or a mineral containing silica. 4. The modification method according to item 1 above, wherein the granular material is alumina or a mineral containing alumina. 5. The modification method according to any one of the above items 1 to 4, wherein the powder or granular material is finer than 9 meshes. 6. The reforming method according to any one of items 1 to 5 above, wherein the total content of alkaline earth metals and alkali metals in the coal used is 0.2% by weight or more based on dry coal. 7. The reforming method according to any one of items 1 to 6 above, wherein the oxygen content of the coal used is 12% by weight or more based on ashless dry coal. 8 While continuously supplying the powder or granular material to the reaction system,
Alkaline earth metals and alkali metals are deposited on the surface,
The modification method according to any one of the above items 1 to 7, wherein the adhering powder or granules are continuously removed from the reaction system. 9 Fill the reactor with inorganic particles in advance,
The reforming method according to any one of the above items 1 to 7, wherein after the start of the reaction, the powder and granules on which alkaline earth metals and alkali metal salts have precipitated and adhered are continuously extracted from the reactor.