JPS61207489A - Method of extracting organic substance in coal with solvent - Google Patents

Abstract

PURPOSE:To extract an organic substance contained in coal at a low temperature under a low pressure with ease, by using a mixed solvent comprising carbon disulfide and N-methyl-2-pyrrolidone or dimethylacetamide. CONSTITUTION:An organic substance contained in coal is extracted with a binary mixed solvent comprising carbon disulfide and N-methyl-2-pyrrolidone or dimethylacetamide. According to the present method, the organic substance contained in coal can be extracted at a relatively low temperature, i.e. about 250 deg.C under a relatively low pressure, i.e. about 100kg/cm<2>G in a short period of time, which not only contributes to the reduction in the energy required in the extraction of coal and in weight of the apparatus used but also enables inexpensive materials for apparatus to be used.

Description

[Detailed description of the invention] "Purpose of invention" [Industrial application field] This invention relates to a method for solvent extraction of coal.

[Prior Art] For a long time in the past, studies have been conducted on technical means for liquefying coal, which is a solid fossil fuel, to use it as a liquid fuel and a chemical raw material. This conventional coal liquefaction method has
There is a method of hydrogenating coal under high temperature and high pressure (hereinafter simply referred to as hydrogenation method) or a method of extracting organic matter in coal with a solvent (hereinafter simply referred to as solvent extraction method). Conventional methods such as this, even in the case of solvent extraction methods, do not have sufficient solvent performance in the methods developed in the past, and require high temperatures and pressures similar to the hydrogenation method, so both methods cannot be used as products. The resulting liquefied product is expensive and insufficient for practical use.

The inventors of this invention previously proposed in Japanese Patent Application No. 58-54564 that carbon disulfide and pyridine, dimethyl sulfoxide, N5N-dimethylformamide or hexamethylphosphorotriamide were used as a solvent for extracting coal. Having proposed a method using a binary mixture as a solvent, this invention relates to a method for solvent extraction of coal using a different mixed solvent than that of the previous application mentioned above.

[Problems to be Solved by the Invention] This invention is a novel method aimed at improving the drawbacks of the conventional solvent extraction methods as described above. That is, this invention lowers the temperature and pressure when extracting coal by changing the solvent in the coal solvent extraction method from the conventional coal tar-based solvent or petroleum distillate-based solvent to a new mixed solvent. , aims to provide a method for extracting coal that is significantly easier than conventional methods.

"Structure of the invention" [Means for solving the problem] In this invention, as a solvent for extracting coal,
Carbon disulfide and N-methyl-2-pyrrolidone (hereinafter simply M
P) or dimethylacetamide (hereinafter simply DMA) is used.

By using these mixed solvents, a considerable amount of organic matter in coal can be extracted at room temperature and pressure. The content of this invention will be explained in detail below using experimental data.

Carbon disulfide, MP and DMA are all conventionally well known solvents. However, when extracting coal with solvent,
Even if these solvents are used alone, sufficient extraction effects cannot be obtained. The invention is based on the discovery that very good extraction effects are obtained when these solvents are used as a mixture. First, Tables 1 and 2 explain the large difference in extraction effect between when these solvents are used alone and when they are used as a mixture.

Table 1 shows that Shin-Yubari coal, which has been crushed to pass through a 60-mesh Tyler sieve, is mixed with the above three individual solvents, an equal volume mixed solvent of carbon disulfide and DMA, and an equal volume of carbon disulfide and MP. It is a table showing an example of the extraction rate of coal when extracted with a mixed solvent for 60 minutes at normal temperature and normal pressure. Unless otherwise specified,
The extraction rate in this table and in the explanation below is 4g of coal.
After stirring and extracting with a 100111 solvent, the extract is separated into an extract and an extraction residue using a centrifugal separator, and the weight of the components (i.e. extracts) in the coal dissolved in the solvent is determined by a drying method by heating the extract under reduced pressure. , expressed as a 100% ratio of the weight of the extract to the weight of the portion of the input coal excluding the ash content.

Table 1 Solvents used Carbon disulfide extracted from Shin-Yubari coal 0.8 DMA
2.6MP
9゜3 Carbon disulfide-DMA 47
．． 0 Carbon disulfide - MP 57.9 Table 2 shows Shinyubari charcoal and Natsuzou charcoal (produced in China) that were crushed to pass through a 60-mesh Tyler sieve in the same way as in Table 1.
is a table showing an example of the extraction rate of coal when the extraction time is shortened to 30 minutes using carbon disulfide and MP alone or a mixed solvent with a different blending ratio of both.

The compositions of the mixed solvents in this table are expressed in volume % of carbon disulfide used in preparing these mixed solvents.

Table 2 Solvent Extraction rate group Natsou charcoal New Zhang charcoal 0
12, 1 9.310 34.
0 31.420
45.130 59.0 51
．． 840 55.550
．． 60.2 55.960
56.070 54
, 5 50.480
41.490 2B, 4
29.1100 1.1 0.8
As is clear from these tables, there is a significant difference in the extraction effect between a single solvent and a mixed solvent, and the mixed solvent used for extraction has a carbon disulfide content of 10 to 90%, preferably 30 to 80%. %, particularly preferably 40-70% by volume
(hereinafter simply referred to as % unless otherwise specified). The extraction rate also varies depending on the type of coal and the composition of the solvent.

The temperature and pressure conditions used when extracting coal by the method of this invention include a temperature range from room temperature to 250'C, preferably 100 to 200'C, and a pressure from atmospheric pressure to the equilibrium vapor pressure in the extraction vessel at 250°C. One can mention pressure.

The amount of solvent used during extraction varies depending on the type of coal, but it is desirable to use 3 to 100 solvent per kg of coal. The amount of solvent used is 1
If it is less than 31 per kGl, the viscosity of the liquid after extraction becomes too high and handling becomes difficult, and the extraction rate decreases. On the other hand, using a solvent of 1001 or more per 1 kg of coal has a small effect on increasing the extraction rate compared to an increase in the amount of solvent used. Therefore, it is recommended that the temperature during extraction be within the range of 100 to 200°C, so that even if extraction is performed using a relatively small amount of solvent, the viscosity of the solvent after extraction is low and a high extraction rate can be obtained. This is advantageous for the following reasons.

The coking coal used in this invention preferably passes through a 60-mesh sieve and passes through a 170-mesh sieve so that about 10% by weight passes through a 16-mesh sieve and passes through a 200-mesh sieve. It is preferable to crush the powder so that it contains about 10% by weight and use it for extraction. If coarse coal grains that hardly pass through a 16-mesh sieve are used as extraction raw materials, it will be difficult to obtain a high extraction rate, and if small-grained coal that can barely pass through a 200-mesh sieve is used, it will be difficult to obtain a high extraction rate after the extraction operation. In this case, it becomes difficult to separate the coal extraction residue and the liquid after extraction.

According to the present invention, coal can be extracted by either a batch extraction method or a continuous extraction method. In the batch extraction method, the extraction rate obtained by one extraction operation is not sufficient, and it is desirable to increase the extraction rate by performing repeated extractions each time using a new solvent or a recovered solvent.

The upper limit of the extraction rate obtained by such repeated extraction is
It varies greatly depending on the type of coal, but in many coals it is 25% or more, and in the case of coal suitable for the method of this invention,
Extraction rates exceeding 40% can be obtained. However, even if this batch extraction is performed 10 times or more, the extraction rate cannot be significantly increased.

The time required for one batch extraction varies depending on the type of coal, but within one hour, and in most cases within 20 minutes, is sufficient. As is clear from the above description, the method of the present invention is preferably carried out by a continuous extraction method, particularly a countercurrent continuous extraction method.

The mixture of the extract containing the organic matter in coal and the extraction residue obtained by the method of this invention can be separated into the extract and the extraction residue by a well-known method such as gravity sedimentation, centrifugation, or filtration. I can do it. This separation operation is facilitated by the use of moderate temperatures as described above. After this separation is completed, the extract can be reseparated into a recovered solvent and extracted organic matter by a well-known method such as evaporation, distillation, or concentration. The recovered solvent after re-separation can be reused as a solvent for the method of this invention without any particular explanation. With this kind of solvent recovery method,
More than 90% of the used solvent can be recovered. The organic matter extracted after removing the solvent is the organic matter contained in the coal. The properties of this organic substance vary depending on the type of coal, but in most cases it is a solid or dark brown substance that emits fluorescence at room temperature or a liquid with a very high viscosity, and the details of its properties are not clear.

The results of elemental analysis of this organic matter are approximately 4 to 10% by weight in total of nitrogen, sulfur, and oxygen, and 84 to 89% by weight of carbon.
, the remainder was hydrogen.

Examples Shin-Yubari charcoal is crushed and passed through a Tyler sieve through 16 meshes but not 60 meshes (hereinafter simply referred to as 16 meshes), and through 60 meshes but not 100 meshes (hereinafter simply referred to as 60 meshes). ),
Those that pass 100 meshes but do not pass 170 meshes (hereinafter simply referred to as 100 meshes) and 170 meshes.
The coal that passed through the mesh was classified into 170 mesh (hereinafter simply referred to as 170 mesh), and dried at 107° C. in a nitrogen stream until it reached a constant weight to obtain raw coal. 2.4 or 8g of this raw coal
Mixed solvent 1001J of equal volumes of r, carbon disulfide, and MP
f in a container and stirred at room temperature for 0 to 180 minutes to perform an extraction operation. After the extraction operation was completed, the contents of the container were separated into an extract and an extraction residue by centrifugation. An extraction time of 0 minutes means that the raw coal and the solvent were immediately subjected to a centrifugal separation operation after mixing. The extract was heated under reduced pressure in an evaporator to distill off the solvent and concentrated, and then the concentrated solution was vacuum-dried at 80° C. until it reached a constant weight. The concentrated liquid after drying is the extract. In this example, the extraction residue was washed with acetone under ultrasonic irradiation at room temperature, vacuum dried at 80°C, and the weight of the extraction residue after vacuum drying was subtracted from the weight of the input coking coal. The weight of the extract was determined, and the extraction rate was calculated from the weight of the extract in the same manner as described above. Table 3 shows the results.

Table 3 Extraction Coal Extraction Rate Hours
Amount 9 "Metshu %0 4.0
60 47.8154゜0 6
0 55.430 4.0 60
55.960 4.0 60
57.91804.0 60
56.930 2.0 60 5
6.330 8.0 60 59
．． 230 4.0 16 51.
930 4.0 100 55.2
30 4.0 170 58.1 As is clear from the above results, the extraction of coal by the method of this invention is completed within a very short time even at low temperatures around room temperature and normal pressure. The extraction time can be further shortened by increasing the extraction temperature within a range in which the vapor pressure of the mixed solvent used does not become extremely high.

"Effects of the Invention" As already mentioned, the advantage of this invention is that solvent extraction of coal can be carried out in a short time under relatively low temperature and pressure conditions of 2.50°C or less and approximately 100kg/cmG or less. Yes, conventional method at a temperature of 350℃ or higher and 100kg/c
Much lower temperatures and pressures are required than when pressures of dG or higher are used. Therefore, it is more advantageous than the conventional method in that it is possible to reduce the energy required for extracting coal, as well as to reduce the weight of the equipment used and to use inexpensive materials for these equipment.

・Applicant Matsu 1) Minoru Miyabi Iino

Claims (1)

[Claims] A method for extracting organic matter from coal using a solvent, which is characterized in that a two-component mixed solvent of carbon disulfide and N-methyl-2-pyrrolidone or dimethylacetamide is used as an extraction solvent.