JPS6025074B2 - Method for producing mixed coal oil containing deashed coal - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing carburized oil containing deashed coal.

Naturally produced coal contains a relatively large amount of ash, which is mainly composed of silica (Si02) and alumina (AI203), and usually accounts for 7 to 25% in coal. included in a certain proportion. When the ash content in such coal is observed with an X-ray microanalyzer, it is clear that the ash content is unevenly distributed in the form of particles with the size of five to several dozen mountains. Conventionally, methods for removing ash from coal include pulverizing raw coal containing ash, mixing the resulting powdered coal with water to create a powdered coal slurry, and then
A method is already known in which oil is added to this slurry as a binder, the powdered coal and oil are granulated as they are, and then the granulated material is separated from the slurry containing ash. The granulated material from which the ash has been removed is pellet-shaped oil-impregnated deashed coal, which is used as fuel. However, such conventional methods have a problem in that ash cannot be removed more fully than from coal. This is because, in order to sufficiently remove the ash content in the coal, it is necessary to crush the coal very finely to a size comparable to the ash content contained in the coal, that is, to a size of 5 mm to several tens of rms. However, if the coal is pulverized too finely, the surface area of the pulverized coal will increase, more oil must be used as a binder, and the granulation time will be very long. There was a problem in that the ash could not be pulverized very finely and the ash could not be sufficiently removed from the coal.
The purpose of this invention is to solve the above-mentioned problem, to make the granulation time very short, and to efficiently produce water slurry of pulverized coal even if the coal containing ash is pulverized very finely. It can be granulated, the amount of ash involved in the granulation process is small, the ash can be removed sufficiently, and carburized oil containing deashed coal with a very low ash content can be produced efficiently in a short time. I'm trying to provide a way that can be done. In order to achieve the above object, this invention mixes oil in a water chiller of ash-containing granulated coal to granulate it, then separates the mixture into granules and an aqueous solution containing ash, and then granulates it. In a method for producing mixed coal oil containing deashed coal, in which mixed granules are mixed with oil to produce mixed coal oil, oil and seeds made of lipophilic granular solids that become granulation nuclei are added to powdered coal slurry containing ash. The mixture is mixed and granulated, heated oil is mixed with the granules made of deashed coal, oil, and seeds to evaporate water, and the granules containing the heated oil are decomposed to produce deashed coal and oil. The gist of this paper is a method for producing Taka coal oil containing deashed coal, which is characterized by separating the mixed coal oil and seeds to obtain TSURU coal oil, and collecting the seeds and returning them to the above granulation process. .

The method of this invention will be explained below with reference to the drawings.

First step: Natural coal containing ash is pulverized using, for example, a wet ball mill to produce powdered coal with a grain size ranging from several hundred grains to several tens of grains. Raw coal usually contains 7 to 25% ash, but the ash is finely ground by pulverization. Next, this pulverized coal containing ash is mixed with water to create a pulverized coal slurry. In some cases, coal may be pulverized into so-called ultra-fine powder with a grain size of several grains. The coal is preferably pulverized in water, and after pulverization, a required amount of water is added to adjust the concentration of the slurry. Second step: Next, oil and seeds made of lipophilic granular solids serving as granulation nuclei are mixed into this differentiated coal slurry and granulated.

Here, as the oil, kerosene, light oil, heavy oil, distillation residue oil, vegetable oil, etc. are used. The amount of oil used is, for example, about 10-3% by weight based on the fine coal. A small amount of surfactant may also be added to facilitate oil dispersion. The seeds to be used as granulation nuclei must have lipophilic properties and be in the form of granular solids so that they can be easily recovered later, and their specific gravity must be the same as that of coal, that is, 1. It is desirable that the value be close to 4. As such a seed, granules made of synthetic resin such as hard polyvinyl chloride or coarse charcoal, etc., having a particle size of about 1 leg to several sides are used. It is usually preferable to mix seeds and powdered coal at a ratio of 1:1, but the total amount of seeds and powdered coal in the IJ slurry is 3% by weight or less, and powdered coal is mixed within a range not exceeding this value. Of course, you can increase or decrease the percentage of seeds used. There are three methods for mixing pulverized coal slather, oil, and seeds.

(i) Mixing seeds into a powdered coal slurry and then mixing oil into this slurry.

(ii) Oil is added to the seeds in advance to make the oil adhere to the surface of the seeds, and then the oiled seeds are mixed into the powdered coal slurry.

(lii) Mixing oil into the powdered coal slurry and then mixing seeds into this slurry.

To granulate the mixture as described above, a granulating device equipped with a wire mesh flywheel or other known granulating device is used.

In this granulation process, oil is attached to the surface of seeds made of lipophilic granular solids, and pulverized coal is sequentially attached to the oil on the surface of the oiled seeds as a core, resulting in so-called transfer granulation. The grains cause the pulverized coal to be granulated very quickly in an accelerated manner, so that the granulation time is very short. Also, since seeds are used, the amount of oil used is extremely small. On the other hand, ash that has been crushed to the same size as pulverized coal remains in the water. Note that if the ash content in the raw coal is very high, for example, about 2% by weight, a primary deashing treatment may be performed before granulation.

In other words, when pulverized coal slurry is mixed with seeds and oil,
It is divided into a liquid phase containing pulverized coal, seeds, and oil, and a slurry consisting of water containing ash. This slurry containing ash is separated from the liquid phase containing pulverized coal, and then the liquid phase containing pulverized coal is washed with clean water. This eliminates children with a high ash content. Third step: Next, the granules made of pulverized coal, oil, and seeds are separated from the chiller and washed to remove ash.

This operation is carried out by, for example, pouring the slurry containing the granules onto a filter and spraying washing water from above. In some cases, the separated granules may be centrifuged to further remove moisture. The slurry containing ash is then introduced into a water treatment device equipped with a thickener, a filter, etc., and treated, thereby separating it into ash and water. Fourth step: Next, heated oil at 70 to 150oC is mixed with the washed granules made of pulverized coal, oil, and seeds, and water is evaporated by suction.

Here, as the heating oil, heavy oil having a relatively high boiling point, distillation residue oil, etc. are used. Note that when low boiling point oil such as kerosene or light oil is used as the oil in the above granulation step, a part of it may evaporate together with water due to suction. In some cases, the evaporated gas containing low-boiling point oil and water is cooled and condensed, and the liquid low-boiling point oil is separated from the water and recovered, which is then returned to the above-mentioned granulation process for reuse. You may. The amount of heating oil mixed is such that the ratio of fine coal to oil in the finally obtained carburized oil is, for example, 1:1. In the above granulation process, less than 3% by weight of oil is added to the pulverized coal, so in the end the heating oil is more than 7% by weight to the pulverized coal, and the total amount is almost the same as the pulverized coal. It should be added so that In addition,
When changing the ratio of fine coal and oil in the mixed coal oil, the amount of heating oil added may be adjusted as appropriate based on the ratio. Fifth step: The granules containing heating oil are decomposed and separated into a mixed coal oil consisting of deashed coal and oil and seeds to obtain a mixed coal oil containing deashed coal, and the seeds are collected to recover the seeds. Return to second granulation step.

In this case, a small amount of oil is attached to the seeds, but these seeds may be returned to the granulation process after adding oil to them, or they may be returned as is without adding oil. good. The mixed coal oil thus produced contains deashed coal from which ash has been sufficiently removed, and can be effectively used as a fuel.

Next, embodiments of the invention will be described. Example Breasol coal (produced in Australia) with an ash content of 7.02% by weight is pulverized to produce powdered coal with a particle size of 200 mesh or less, that is, a grain size of 74 mounds or less, and water is mixed with this to produce powdered coal slurry. .

Next, granular seeds were mixed into this powdered coal slurry. The seeds are made of hard polyvinyl chloride and have a short cylindrical shape with a diameter of about 3 ribs and a height of about 1.5 skin, and the specific gravity is 1.4.
The specific gravity approximated that of coal was used. The blending amounts in the slurry were 5% by weight of powdered coal and 5% by weight of seeds. Next, add kerosene to this slurry in an amount of 2 times the amount of pulverized coal.
This slurry was introduced into a granulator and granulated. After that, the granules are separated from the slurry and washed with water to remove the ash, and heated oil consisting of C heavy oil of about 90 CO is applied to the washed granules at about 8 CO to pulverized coal.
% by weight and the water was evaporated by suction. This suction also evaporated kerosene along with the water, but the amount was small. Then, the granules containing heating oil were decomposed to separate the seeds to obtain a mixed coal oil in which the ratio of deashed coal and oil (kerosene + heavy oil) was approximately 1:1. On the other hand, the separated seeds were collected and returned to the granulation process for reuse. In order to measure the ash content of the deashed coal in the hawk coal oil produced in this way, the oil was extracted with a solvent and the ash content of the deashed pulverized coal obtained was measured. It contained only 1.74% by weight of ash. For comparison, when the same raw coal was deashed using a conventional method that does not use seeds, the resulting oil-impregnated deashed coal contained ash of 3.32% by weight based on the pulverized coal. It was As described above, the method of the present invention uses seeds made of lipophilic granular solids for the granulation of pulverized coal together with oil, so the granulation time is very short. Therefore, even if the coal containing ash is pulverized very finely, the water slurry of this fine coal can be efficiently granulated, and the amount of ash entrained in the granulation process is very small, and the ash can be removed sufficiently. can do.

Furthermore, since heating oil is added to the granules and the granules are simultaneously suctioned and dehumidified, the drying step of the granules can be omitted.
Therefore, according to the method of the present invention, peat oil containing deashed coal with a very low ash content can be efficiently produced in a short time, and the resulting mixed coal oil is easily combustible and has a low ash content per unit amount. Not only does it have a high calorific value, it produces very little ash and is easily stabilized.

[Brief explanation of the drawing]

The drawings are block diagrams sequentially illustrating the steps of implementing the method of the invention.

Claims (1)

[Claims] 1 Mix oil into a water slurry of pulverized coal containing ash and granulate it, then separate the mixture into granules and an aqueous solution containing ash, and then mix the granules with oil to produce mixed coal oil. do,
In a method for producing mixed coal oil containing deashed coal, a pulverized coal slurry containing ash is mixed with oil and seeds made of lipophilic granular solids that serve as granulation nuclei, and then granulated to form deashed coal, oil, and seeds. The granules containing the heated oil are mixed with heated oil to evaporate water, the granules containing the heated oil are decomposed to obtain a mixed coal oil consisting of deashed coal and oil, and the seeds are collected and the above-mentioned A method for producing mixed coal oil containing deashed coal, characterized in that the coal is returned to a granulation process.