KR101710292B1 - Method for producing residue coal - Google Patents

Abstract

In the method for producing a by-product carbon according to the present invention, in the solvent separator (10), the solvent is evaporated and separated from the solid concentrate separated in the gravity sedimentation accelerator (7) to obtain a by-product mixture in which the solvent remains in the by-product. Subsequently, in the dryer 11, the solvent remaining from the by-product mixture is evaporated and separated to obtain by-product carbon. At this time, in the dryer 11, the residual solvent from the by-product mixture is evaporated and separated by using the heat of the by-product mixture itself. Thereby, the apparatus for drying the by-product mixture is simplified to reduce the cost of drying.

Description

[0001] METHOD FOR PRODUCING RESIDUE COAL [0002]

The present invention relates to a method for producing byproducts produced as byproducts in obtaining ashless coal from which coal ash is removed.

Patent Document 1 discloses a method for producing ashless coal. In this production method, a slurry is prepared by mixing a coal raw material mixed with coking coal and a solvent, and heating the obtained slurry to extract a coal component soluble in the solvent. From the slurry from which the coal component is extracted, A solution containing a coal component soluble in a solvent and a solid concentrate containing a coal component insoluble in the solvent are separated and the solvent is separated from the separated solution to obtain an ashless coal.

Japanese Patent Application Laid-Open No. 2009-227718

By the way, in the manufacturing process of the ashless coal, besides the final product, the by-product, the by-product is produced as a by-product.

The by-product carbon is obtained by evaporating the solvent from the solid concentrate. As the process, first, the solvent is evaporated and separated from the solid content concentrate to obtain a by-product mixture in which the solvent remains in the by-product. Then, the residual solvent is evaporated and separated from the by-product mixture to obtain by-products.

However, when a large amount of the by-product mixture is dried to obtain the by-product, there is a problem in that there is no drying method capable of setting the temperature of the by-product mixture at the boiling point of the solvent (about 240 캜) or more. As one of the drying means, there is a steam tube dryer, but since the steam temperature is 220 ° C at maximum, it is necessary to prolong the residence time and increase the cost.

It is an object of the present invention to provide a method for producing a by-product which can simplify the apparatus for drying the by-product mixture and reduce the cost of drying the by-product mixture.

The method for producing by-product carbon according to the present invention comprises an extraction step of heating a slurry obtained by mixing coal and a solvent to extract a coal component soluble in the solvent, and a step of mixing the slurry obtained in the extraction step with a coal component Separating the dissolved solution into a solid concentrate obtained by concentrating a coal component insoluble in a solvent and a byproduct collecting step of separating the solvent from the solid concentrate separated in the separating step to obtain a by- Wherein the by-product burning step includes a by-product mixture obtaining step of obtaining a by-product mixture in which the solvent remains in the by-product carbon by evaporating and separating the solvent from the solid concentrate separated in the separating step, And a by-product carbon drying step for obtaining by-product carbon by evaporation and separation, Wherein the residual solvent from the by-product mixture is evaporated and separated using the heat of the by-product mixture itself.

According to the method for producing by-products of the present invention, it is possible to simplify the apparatus for drying the by-product mixture and reduce the cost of drying the by-product mixture.

1 is a schematic diagram of an ashless coal manufacturing facility.
2 is a graph showing the evaluation result of the drying time.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Production method of ashless coal)

The method for producing the by-product carbon according to the present embodiment is carried out in the ashless coal manufacturing facility 100 used in the method for producing ashless coal. As shown in FIG. 1, the ashless coal manufacturing facility 100 includes a coal hopper 1, a solvent tank 2, a slurry tank 3, and a feed pump 3, in this order from the upstream side of the HPC manufacturing process. A pretreatment unit 4, a preheater 5, an extraction tank 6, a gravity sedimentation accelerator 7, a filter unit 8, a solvent separator 9 · 10 and a dryer 11.

The production method of ashless coal has a slurry preparation process, an extraction process, a separation process, an ashless coal acquisition process, and a by-product shot acquisition process. The method for producing by-product carbon of the present embodiment includes the slurry preparation step, the extraction step, the separation step, and the step of obtaining a by-product from among the above-mentioned steps. Each step will be described below. The coal to be used as a raw material in the present production method is not particularly limited and bituminous coal having a high extraction ratio may be used, or cheaper crude azalea (bituminous coal, lignite) may be used. The term "ash-free" means that the ash content is 5% by weight or less, preferably 3% by weight or less.

(Slurry preparing process)

The slurry preparing step is a step of mixing coal and a solvent to prepare a slurry. This slurry preparation step is carried out in slurry preparation (3) in Fig. The raw coal is charged into the slurry tank 3 from the coal hopper 1 and the solvent is introduced into the slurry tank 3 from the solvent tank 2. The coal and the solvent injected into the slurry preparation 3 are mixed in the agitator 3a to obtain a slurry composed of coal and a solvent.

The mixing ratio of coal to the solvent is, for example, 10 to 50 wt%, more preferably 20 to 35 wt%, based on dry coal.

(Extraction process)

The extraction step is a step of heating the slurry obtained in the slurry preparation step to extract (soluble in a solvent) a coal component soluble in the solvent. This extraction process is carried out in the preheater 5 and the extraction tank 6 in Fig. The slurry prepared in the slurry preparation (3) was supplied to the pre-heater (5) by the feed pump (4) and heated to a predetermined temperature. Then, the slurry was supplied to the extraction tank (6) and stirred in the agitator The extraction is carried out while being maintained at a predetermined temperature.

In the case of heating the slurry obtained by mixing the coal and the solvent to extract the coal component soluble in the solvent, a solvent having a large dissolving power for coal, in many cases, an aromatic solvent (a solvent for a hydrogenpolymer or a nonhydrocarbon resin) The coal is mixed and heated, and the organic components in the coal are extracted.

Non-hydrogenated solvents are coal derivatives, which are solvents mainly composed of bicyclic aromatic groups, which are purified mainly from the products obtained from coal. This non-hydrogen-containing solvent is stable even in a heated state and is excellent in affinity with coal. Therefore, the ratio of the soluble component (here, coal component) extracted in the solvent (hereinafter also referred to as extraction ratio) Is a solvent which can be easily recovered by the method of Examples of the main components of the non-hydrogenated naphthalene solvent include naphthalene, naphthalene, methylnaphthalene, dimethylnaphthalene and trimethylnaphthalene, which are two-ring aromatic compounds, and naphthalenes and aliphatic hydrocarbons having aliphatic side chains, , Fluorenes, and alkylbenzenes having biphenyls or long chain aliphatic side chains therein.

In the above description, the case where the non-hydrogen cyanide compound is used as a solvent has been described. However, it is needless to say that a hydrogen cyanide compound (including coal liquified oil) typified by tetralin can be used as a solvent to be. When a hydrogenated castor oil solvent is used, the yield of ashless coal is improved.

The boiling point of the solvent is not particularly limited. From the viewpoints of the pressure reduction in the extraction process and the separation process, the extraction rate in the extraction process, and the recovery rate of the solvent in the process for acquiring the unburned solvent, for example, a solvent having a boiling point of 180 to 300 캜, particularly 240 to 280 캜, do. In the present embodiment, the boiling point of the solvent is about 240 캜.

The heating temperature of the slurry in the extraction step is not particularly limited so long as the solvent soluble component can be dissolved and is preferably 300 to 420 占 폚 in view of sufficient dissolution of the solvent soluble component and improvement of the extraction ratio, , And 360 to 400 deg. In the present embodiment, the preheater 5 heats the slurry so that the by-product mixture supplied to the dryer 11 has a heat quantity capable of evaporating and separating the remaining solvent from the by- The temperature of the solid concentration liquid supplied to the solvent separator 10 is adjusted.

The heating time (extraction time) is also not particularly limited, but is, for example, 10 to 60 minutes from the viewpoint of sufficient dissolution and improvement of the extraction ratio. The heating time is the sum of the heating times in the preheater 5 and the extraction tank 6 in Fig.

The extraction step is carried out in the presence of an inert gas such as nitrogen. The pressure in the extraction tank 6 varies depending on the temperature at the time of extraction and the vapor pressure of the solvent to be used, but is preferably 1.0 to 2.0 MPa. When the pressure in the extraction tank 6 is lower than the vapor pressure of the solvent, the solvent can not be volatilized and can not be trapped in the liquid phase, so that the solvent can not be extracted. In order to trap the solvent in the liquid phase, a pressure higher than the vapor pressure of the solvent is required. On the other hand, if the pressure is too high, the cost of the apparatus and the operation cost become high, which is not economical.

(Separation step)

The separation step is a step in which the slurry obtained in the extraction step is subjected to gravity sedimentation by a solution in which a coal component soluble in a solvent is dissolved and a solid concentrate in which a coal component insoluble in the solvent (solvent insoluble component, for example, ash) (Solvent insoluble matter concentrate). This separation process is carried out in the gravitational sedimentation emphasis 7 in Fig. The slurry obtained in the extraction step is separated into a supernatant as a solution and a solid concentrate in gravity sedimentation 7 by gravity. The supernatant at the upper part of the gravity sedimentation accelerator 7 is discharged to the solvent separator 9 via the filter unit 8 as required and the solid concentrate settled at the lower part of the gravity sedimentation accelerator 7 is recovered in the solvent separator 10).

The gravity sedimentation method is a method in which a slurry is retained in a tank to sediment and separate a solvent insoluble component by gravity. The solvent insoluble component (for example, ash) having a specific gravity larger than that of the solution in which the coal component soluble in the solvent is dissolved precipitates under the gravity sedimentation accelerator 7 by gravity. Continuous separation treatment is possible by continuously supplying the slurry into the tank while continuously discharging the supernatant from the upper portion and the solid concentrate from the lower portion continuously.

It is preferable that the gravity incising stress 7 be kept warm (or heated) or pressurized in order to prevent re-precipitation of the solvent-soluble components eluted from the coal. The heating (heating) temperature is, for example, 300 to 380 占 폚, and the pressure in the bath is, for example, 1.0 to 3.0 MPa.

Further, as a method for separating a solution containing a coal component dissolved in a solvent from the slurry obtained in the extraction step, there are filtration method, centrifugal separation method and the like in addition to the gravitational sedimentation method.

(Acquisition process of non-burned coal)

The unburned carbon obtaining step is a step of obtaining an ashless coal (HPC) by evaporating and separating the solvent from the solution (supernatant) separated in the separation step. This ash recovery step is carried out in the solvent separator 9 in Fig. The solution separated in the gravity sedimentation accelerator 7 is filtered in the filter unit 8 and then supplied to the solvent separator 9 and the solvent is evaporated and separated from the supernatant in the solvent separator 9. Here, it is preferable that the solvent is evaporated and separated from the solution in the presence of an inert gas such as nitrogen. In the present embodiment, the solvent is evaporated and separated from the solution in the nitrogen gas introduced into the solvent separator 9.

As a method for separating the solvent from the solution (supernatant), a general distillation method, an evaporation method, and the like can be used. The solvent separated in the solvent separator 9 is returned to the solvent tank 2 and circulated and used repeatedly. In addition, it is preferable, but not essential, to use the solvent circulating (this also applies to the by-product collecting step described later). By separating the solvent from the supernatant, it is possible to obtain substantially ash-free ashless coal (HPC).

Non-ash barely contains ash, has no moisture, and shows higher calorific value than raw coal. In addition, even if the softening and meltability (fluidity), which is an especially important quality as raw material for iron coke, is significantly improved and the raw coal is not softened and melted, the obtained ashless coal (HPC) has good softening and melting properties. Therefore, the ashless carbon can be used, for example, as a blend of coke raw materials. In addition, the ashless coal, which contains almost no ash, has a high combustion efficiency and can reduce the generation of coal fly ash. Therefore, the use of a high efficiency combined cycle power generation system as a gas turbine direct injection fuel by gas turbine combustion is also attracting attention.

(Process of obtaining by-product)

The by-product burning process is a process for evaporating and separating the solvent from the solid concentrate separated in the separation process to obtain by-products. This by-product-obtaining step includes a by-product mixture-acquiring step and a by-product drying step.

≪ Production process of by-product mixture >

The by-product mixture-obtaining step is a step of obtaining a by-product mixture in which the solvent remains in the by-product, by evaporating the solvent from the solid concentrate separated in the separation step. This by-product mixture obtaining step is carried out in the solvent separator 10 in Fig. The solid concentrate separated from the gravity sedimentation accelerator 7 is supplied to the solvent separator 10, and the solvent is evaporated and separated from the solid concentrate in the solvent separator 10. Here, it is preferable that the solvent is evaporated and separated from the solid concentration concentrate in the presence of an inert gas such as nitrogen. In this embodiment, the solvent separator 10 is a flash distillation tank used in a flash distillation method. In the flash distillation method, a solid concentrate is sprayed in a tank in a nitrogen gas atmosphere to evaporate and separate the solvent.

The method of separating the solvent from the solid concentrate is not limited to the flash distillation method, and a general distillation method and an evaporation method can be used in the same manner as the above-mentioned step of acquiring the non-monofilaments. The solvent separated in the solvent separator 10 is returned to the solvent tank 2, circulated and used repeatedly. By separating the solvent from the solid concentration concentrate, a by-product mixture containing 5 to 10% by weight of solvent in the by-product can be obtained.

Here, the solid concentrate liquid separated from the gravity sedimentation accelerator 7 is in a high-temperature and high-pressure state in which the solvent is not evaporated and separated. The solid concentrated liquid is injected into the solvent separator 10 whose interior is at atmospheric pressure, whereby the pressure of the solid concentrated liquid is released. As a result, the boiling point of the solvent is lowered, and the solvent is evaporated and separated at a time from the solid content concentrate at a high temperature. At this time, the temperature of the solid concentrate supplied to the solvent separator 10 is adjusted so that the by-product mixture supplied to the dryer 11 thereafter has a heat quantity capable of evaporating and separating the remaining solvent from the by-product mixture. This temperature adjustment is performed by the preheater 5 which heats the slurry prepared in the slurry preparation (3) as described above. This temperature adjustment may be performed by heating the solid concentrate before it is separated from the gravitational sedimentation 7 and supplied to the solvent separator 10. The temperature may be adjusted by heating the slurry prepared in the slurry preparation (3) and the solid concentrate separated from the gravity sedimentation accelerator (7), respectively.

<Process for drying secondary coal>

The by-product drying process is a process for evaporating and separating residual solvent from the by-product mixture to obtain by-products. This by-product drying step is carried out in the dryer 11 in Fig. The by-product mixture obtained in the solvent separator 10 is supplied to the dryer 11, and the solvent remaining from the by-product mixture is evaporated and separated in the dryer 11. It is preferable that the solvent is evaporated and separated from the by-product mixture in the presence of an inert gas such as nitrogen. In the present embodiment, the dryer 11 is a rotary dryer for retaining and stirring the by-product mixture while flowing nitrogen gas as a carrier gas therein. By separating the residual solvent from the by-product mixture, it is possible to obtain by-products (RC, residual coal) in which a solvent insoluble component including ash and the like is concentrated.

The by-products contain ash but have no moisture, and have enough heat. The by-product carbon does not exhibit softening and melting properties, but it does not inhibit the softening and melting properties of other coals contained in the blended carbon when the blended carbon is used as the blended carbon because the oxygen-containing functional groups are eliminated. Therefore, this by-product can be used as a part of the blended carbon of the coke raw material in the same manner as ordinary non-coking cokes, and can also be used for various fuels without being made of coke coke.

Here, in the present embodiment, in the dryer 11, the residual solvent from the by-product mixture is evaporated and separated by using the heat of the by-product mixture itself, which is a mixture containing the by-products and the solvent. That is, the dryer 11 is merely stirring and stirring the by-product mixture, and does not impart any heat to the by-product mixture. In addition, the heat of the by-product mixture itself refers to the heat (contained) of the by-product mixture obtained by separating the solvent from the solid component concentrate and does not refer to the heat generated from the by-product mixture by the chemical reaction. By-product mixture itself has heat, so the by-product mixture has a certain amount of heat. The heat amount of the by-product mixture is an amount capable of vaporizing and separating the solvent remaining from the by-product mixture. If the main component of the solvent is methylnaphthalene, the heat required to evaporate and separate the solvent in a unit amount is 330 kilograms / kilogram (kJ / kg) (the amount of heat required to evaporate 1 kilogram of solvent). As described above, by adjusting the temperature of the solid concentration liquid supplied to the solvent separator 10, the by-product mixture supplied to the dryer 11 has such a heat quantity.

Normally, in order to dry the powder, a device for applying heat to the powder is required. However, the by-product mixture obtained in the by-product mixture obtaining step [solvent separator (10)] itself has considerable heat. Therefore, it is not necessary to apply heat to the by-product mixture by evaporating and separating the residual solvent from the by-product mixture using the heat of the by-product mixture itself. Thereby, the apparatus for drying the by-product mixture can be simplified and the cost for drying the by-product mixture can be reduced.

Further, by adjusting the temperature of the solid concentration liquid supplied to the by-product mixture obtaining step (solvent separator 10), the by-product mixture supplied to the by-product drying step (dryer 11) So as to have a heat quantity capable of evaporating and separating the refrigerant. In general, it is more efficient to apply heat to the liquid than to apply heat to the solid. Therefore, it is easier to adjust the temperature of the concentrated solid liquid, which is liquid than the solidified by-product mixture to some extent. Therefore, the temperature of the solid concentration liquid supplied to the by-product mixture obtaining step (solvent separator 10) is adjusted instead of adjusting the temperature of the by-product mixture supplied to the by-product drying step [the dryer 11]. Thereby, a heat quantity capable of evaporating and separating the remaining solvent from the by-product mixture can be suitably given to the by-product mixture.

Further, by heating at least one of the slurry prepared in the slurry preparation (3) and the solid concentration liquid separated from the gravity sedimentation 7, the temperature of the solid concentration liquid supplied to the by-product mixture obtaining step (solvent separator (10) . Since the slurry or solid concentrate is a liquid, heat can be efficiently given. Therefore, by heating the slurry or the solid concentrate, the temperature of the solid concentrate supplied to the by-product mixture obtaining step can be adjusted appropriately.

(Evaluation of drying time)

Then, the time required for drying the by-products was evaluated by varying the drying temperature. A tubular furnace was used for the evaluation. As a procedure of evaluation, first, the temperature was raised so that the furnace temperature became a predetermined drying temperature while flowing nitrogen gas through the furnace. Then, a sample made of a mixture of by-products containing 28% by weight of a solvent was placed on a porcelain dish having a thermocouple attached thereto and placed in a furnace. Thereafter, the measurement of the drying time was started when the temperature of the sample reached a predetermined drying temperature. After the lapse of a predetermined time, the sample was taken out and the content of the solvent was examined. The evaluation by this procedure was carried out at different drying temperatures of 210 캜, 250 캜 and 270 캜. The evaluation results are shown in Fig.

The time required for the solvent content of the sample to decrease to 2% by weight was about 30 minutes at 210 캜, about 15 minutes at 250 캜, and about 10 minutes at 270 캜. It was found that the drying time can be shortened to about half when the drying temperature is 250 DEG C as compared with the case where the drying temperature is 210 DEG C corresponding to the steam temperature of the steam tube dryer. It was also found that the drying time can be shortened to about 1/3 when the drying temperature is 270 ° C as compared with the case where the drying temperature is 210 ° C.

(effect)

As described above, according to the method for producing a by-product carbon according to the present embodiment, in the by-product drying step [the dryer (11)], the residual heat from the by- Evaporate and separate. Normally, in order to dry the powder, a device for applying heat to the powder is required. However, the by-product mixture obtained in the by-product mixture obtaining step [solvent separator (10)] itself has considerable heat. Therefore, it is not necessary to apply heat to the by-product mixture by evaporating and separating the residual solvent from the by-product mixture using the heat of the by-product mixture itself. Thereby, the apparatus for drying the by-product mixture can be simplified, and the cost of drying the by-product mixture can be reduced.

Further, by adjusting the temperature of the solid concentration liquid supplied to the by-product mixture obtaining step (solvent separator 10), the by-product mixture supplied to the by-product drying step (dryer 11) So as to have a heat quantity capable of evaporating and separating the refrigerant. In general, it is more efficient to apply heat to the liquid than to apply heat to the solid. Therefore, it is easier to adjust the temperature of the concentrated solid liquid, which is liquid than the solidified by-product mixture to some extent. Therefore, the temperature of the solid concentrate supplied to the by-product mixture-collecting step is adjusted instead of adjusting the temperature of the by-product mixture supplied to the by-product drying step. Thereby, a heat quantity capable of evaporating and separating the remaining solvent from the by-product mixture can be suitably given to the by-product mixture.

Further, at least one of the slurry and the solid concentration liquid is heated to adjust the temperature of the solid concentration liquid supplied to the by-product mixture obtaining step (solvent separator 10). Since the slurry or solid concentrate is a liquid, heat can be efficiently given. Therefore, by heating the slurry or the solid concentrate, the temperature of the solid concentrate supplied to the by-product mixture obtaining step can be adjusted appropriately.

Further, in the by-product mixture obtaining step (solvent separator (10)), the solid content concentrate which has been brought into a high-temperature and high-pressure state in which the solvent is not evaporated and separated is injected into an atmospheric pressure container to open the pressure of the solid content concentrate. As a result, the boiling point of the solvent is lowered, and the solvent is evaporated and separated at a time from the high-temperature solid concentrate, whereby the solvent can be appropriately evaporated and separated from the solid concentrate.

(Modification of this embodiment)

Although the embodiment of the present invention has been described above, the present invention is not limited to the specific examples, and the present invention is not limited to the specific embodiments. The functions and effects described in the embodiments of the invention are merely a list of the most appropriate actions and effects arising from the present invention, and the actions and effects of the present invention are limited to those described in the embodiments of the present invention It is not.

This application is based on Japanese Patent Application (Japanese Patent Application No. 2013-025509) filed on February 13, 2013, the content of which is incorporated herein by reference.

In the method for producing a by-product carbon of the present invention, the apparatus for drying the by-product mixture can be simplified to reduce the cost of drying.

1: Coal Hopper
2: solvent tank
3: Slurry preparation
3a: stirrer
4: Feed pump
5: Preheater
6: Extraction tank
6a: stirrer
7: gravity sedimentation emphasis
8: Filter unit
9, 10: solvent separator
11: Dryer
100: Non-ferrous production facility

Claims (4)

An extraction step of heating a slurry obtained by mixing coal and a solvent to extract a coal component soluble in the solvent,
A separation step of separating the slurry obtained in the extraction step into a solution in which a coal component soluble in a solvent is dissolved and a solid concentrate in which a coal component insoluble in a solvent is concentrated;
And a byproduct collecting step of obtaining by-product carbon by evaporating and separating the solvent from the solid concentrate separated in the separating step,
The above-mentioned by-
A by-product mixture acquiring step of evaporating and separating the solvent from the solid concentrate separated in the separating step to obtain a by-product mixture in which the solvent remains in the by-product;
And a by-product burning step of evaporating and separating the remaining solvent from the by-product mixture to obtain by-product carbon,
In the step of drying the by-product, the remaining solvent is evaporated and separated from the by-product mixture using the heat of the by-product mixture itself,
By heating the solid concentrate supplied to the by-product mixture obtaining step so that the by-product mixture supplied to the by-product drying step has a heat quantity capable of evaporating and separating the solvent remaining from the by-product mixture, And the temperature of the solid concentration liquid supplied to the mixture obtaining step is adjusted. delete delete The method according to claim 1,
The separation step is performed under a pressurized condition,
Wherein the solvent is evaporated and separated from the solid concentration concentrate by spraying a solid concentrate in a high-temperature and high-pressure state in which the solvent is not evaporated and separated in the by-product mixture-acquiring step into an atmospheric pressure vessel.

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