JP2016056282A - Method and apparatus for producing ashless coal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ashless coal production method capable of shortening the extraction time of solvent soluble coal components.SOLUTION: An ashless coal production method of the present invention includes the steps of: heating an extraction solvent; obtaining pasted coal by mixing a pasting solvent with coal; obtaining slurry by mixing the extraction solvent with the pasted coal; separating a solution in which coal components are dissolved from the slurry; and evaporating and separating the extraction solvent and the pasting solvent from the separated solution. In the heating step, the temperature of the extraction solvent is preferably adjusted to 330°C or more and 450°C or less. In the pasted coal obtaining step, the concentration of coal in the pasted coal is preferably adjusted to 40 mass% or more and 70 mass% or less in terms of anhydrous coal. In the slurry obtaining step, the extraction solvent is preferably mixed with the paste coal in a turbulent flow state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing ashless coal and an apparatus for producing ashless coal.

  Coal is widely used as a raw material for fuel or chemicals for thermal power generation and boilers, and as one of environmental measures, development of a technology for efficiently removing ash in coal is strongly desired. For example, in a high-efficiency combined power generation system using gas turbine combustion, attempts have been made to use ash-free charcoal (HPC) from which ash has been removed as a fuel to replace liquid fuel such as LNG. Attempts have also been made to use ashless coal as coking coal for ironmaking coke such as blast furnace coke.

  As a method for producing ashless coal, a method has been proposed in which a solution containing a coal component soluble in a solvent (hereinafter referred to as a solvent-soluble component) is separated from a slurry by using a gravity sedimentation method (for example, Japanese Patent Application Laid-Open No. 2009-2009). No. 227718). This method includes a slurry preparation step in which coal and a solvent are mixed to prepare a slurry, and an extraction step in which the slurry obtained in the slurry preparation step is heated to extract a solvent-soluble component. Further, this method includes a solution separation step for separating the solution in which the solvent-soluble component is dissolved from the slurry from which the solvent-soluble component has been extracted in the extraction step, and an ashless by separating the solvent from the solution separated in the solution separation step. And an ashless coal acquisition step for obtaining charcoal.

  In the extraction step of the conventional ashless coal manufacturing method, the slurry obtained in the slurry preparation step is heated to a predetermined temperature and supplied to the extraction tank. And the slurry supplied to the extraction tank is hold | maintained at predetermined temperature, stirring with a stirrer, and extraction of a solvent soluble component is performed. In the extraction step, the slurry is retained in the extraction tank for about 10 to 60 minutes in order to sufficiently dissolve the solvent-soluble component in the solvent. The “extraction rate” means the ratio of the mass of manufactured ashless coal to the mass of coal as a raw material.

  Here, since the time required for extraction of the solvent-soluble component in the extraction step greatly affects the production time of ashless coal, shortening of the extraction time is conventionally required.

JP 2009-227718 A

  This invention is made | formed based on the above situations, and it aims at providing the manufacturing method of ashless coal, and the manufacturing apparatus of ashless coal which can shorten the extraction time of a solvent soluble component.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the extraction time of the solvent-soluble component can be shortened by rapidly raising the temperature of the slurry in which the solvent and coal are mixed. The reason why the extraction time of solvent-soluble components is shortened by rapid temperature increase is that the coal components soluble in the solvent include coal components that dissolve immediately upon temperature increase and, after temperature increase, for example, slowly aging in an extraction tank This is considered to be because the coal component that dissolves due to gradual aging due to rapid temperature rise becomes easier to dissolve.

  That is, the invention made to solve the above problems includes a step of heating an extraction solvent, a step of obtaining pasted coal by mixing a pasting solvent and coal, and a mixing of the extraction solvent and pasted coal. Production of ashless coal comprising: a step of obtaining a slurry by the step of separating a solution in which the coal component is dissolved from the slurry; and a step of evaporating and separating the extraction solvent and the pasting solvent from the separated solution. Is the method.

  The method for producing ashless coal includes a step of obtaining a slurry by mixing a heated extraction solvent and pasted coal, and the pasted coal is quickly mixed with the heated extraction solvent. Further, by reducing the amount of the pasting solvent contained in the pasted coal relative to the amount of the extracting solvent, the slurry rapidly rises to a temperature at which the solvent-soluble component is easily extracted, and the solvent can be used. Soluble components are extracted quickly. As a result, the extraction time of the solvent-soluble component can be shortened by the method for producing ashless coal.

  In the heating step, the temperature of the extraction solvent may be 330 ° C. or higher and 450 ° C. or lower. Thus, by making the temperature of the extraction solvent heated in the heating step within the above range, the slurry in which the extraction solvent and pasted coal are mixed is reliably heated to the extraction temperature at which the extraction rate becomes high, The extraction rate of the solvent-soluble component in the slurry acquisition step is further improved.

  In the pasted coal acquisition step, the concentration of coal in the pasted coal may be 40% by mass or more and 70% by mass or less based on anhydrous carbon. Thus, by making the density | concentration of the coal in pasted coal into the said range in the pasted coal acquisition process, the coal in pasted coal is efficiently heated at the said slurry acquisition process. As a result, the temperature of the slurry is more reliably increased so that the solvent-soluble component is easily extracted, the solvent-soluble component is extracted more quickly, and the extraction time of the solvent-soluble component is further shortened.

  In the slurry obtaining step, the extraction solvent may be mixed with pasted coal in a turbulent state. Thus, by mixing the extraction solvent with the pasted coal in a turbulent state in the slurry acquisition step, the mixing of the extraction solvent and the pasted coal is promoted in the slurry acquisition step, and more solvent soluble The components can be dissolved in the extraction solvent.

  The slurry obtaining step may include a step of pumping the pasted coal into the extraction solvent. Thus, the slurry acquisition step includes the step of pumping the pasted coal into the extraction solvent, so that the mixing of the extraction solvent and the pasted coal is promoted in the slurry acquisition step, and more solvent-soluble components. Can be dissolved in the extraction solvent.

  In the pumping step, a predetermined amount of pasted coal may be pressurized and intermittently pumped. In this way, by pressurizing and intermittently pumping a predetermined amount of pasted coal, it is possible to realize the pumping of pasted coal into the extraction solvent with a simple configuration while continuing to supply the extraction solvent, Increase in equipment cost can be suppressed.

  In the pumping step, the pasted coal may be continuously pumped by a pump. Thus, by continuously pumping pasted coal with a pump, it is easy to adjust the pumping amount of pasted coal, and pasted coal can be stably pumped. Moreover, the deterrent effect with respect to the pipe | tube etc. which supply pasted coal obstruct | occlude with pasted coal is also heightened.

  Further, another invention made to solve the above problems includes a heating section for heating the extraction solvent, a preparation section for obtaining pasted coal by mixing the pasting solvent and coal, and the above extracting solvent and paste. A mixing unit that obtains a slurry by mixing coal, a solid-liquid separation unit that separates the solution in which the coal component is dissolved from the slurry, and the extraction solvent and the pasting solvent from the solution separated by the solid-liquid separation unit An ashless coal production apparatus comprising a solvent separation unit that evaporates and separates.

  The ashless coal manufacturing apparatus includes a mixing unit that obtains a slurry by mixing a heated extraction solvent and pasted coal. As a result, the pasted coal is rapidly mixed with the heated extraction solvent, the slurry rapidly rises to a temperature at which the solvent-soluble component is easily extracted, and the solvent-soluble component is rapidly extracted. As a result, the ashless coal production apparatus can shorten the extraction time of the solvent-soluble component. Also, the inside of the mixing unit of the ashless coal production apparatus is at a high pressure to prevent solvent volatilization, but the ashless coal production apparatus uses the pasted coal as a coal raw material to be supplied. It is possible to control the supply of coal raw material without being greatly affected by the pressure difference between the supply source and the supply source of coal raw material.

  The mixing unit may include an extraction tank that stores the slurry. Thus, by having the extraction tank which stores a slurry in a mixing part, the said solvent soluble component can be extracted more reliably and an extraction rate improves more.

  The “pasted coal” means a mixture of pasty coal and a solvent. The “anhydrous-based coal concentration” means the ratio of the mass of the coal when dried to an anhydrous carbon state to the total mass including the solvent of the pasted coal.

  As described above, according to the method for producing ashless coal and the apparatus for producing ashless coal of the present invention, the extraction time of the solvent-soluble component can be shortened.

It is the schematic which shows the ashless coal manufacturing apparatus which concerns on 1st embodiment of this invention. It is the schematic which shows the ashless coal manufacturing apparatus which concerns on 2nd embodiment of this invention. It is a figure which shows the test equipment of solvent soluble component extraction evaluation. It is a graph which shows the relationship between the extraction time measured by solvent soluble component extraction evaluation, and an extraction rate.

  Hereinafter, an embodiment of an ashless coal manufacturing apparatus and an ashless coal manufacturing method according to the present invention will be described in detail.

[First embodiment]
The ashless coal production apparatus 1 in FIG. 1 obtains pasted coal by mixing an extraction solvent supply unit 2 for supplying an extraction solvent, a heating unit 3 for heating the extraction solvent, and a pasting solvent and coal. The preparation unit 4, the pasted coal supply unit 5 for supplying pasted coal, the mixing unit 6 for obtaining a slurry by mixing the extraction solvent and the pasted coal, and a solid solution for separating the solution in which the coal component is dissolved from the slurry. The apparatus mainly includes a liquid separation unit 7 and a first solvent separation unit 8 that evaporates and separates the extraction solvent and the pasting solvent from the solution separated by the solid-liquid separation unit 7. The first solvent separation unit 8 evaporates and separates the extraction solvent and the pasting solvent from the solution, whereby ashless coal (HPC) is obtained. The ashless coal production apparatus 1 is separated from the solid concentrate containing the coal component separated by the solid-liquid separation unit 7 and insoluble in the extraction solvent and the pasting solvent (hereinafter referred to as a solvent-insoluble component). A second solvent separation unit 9 for obtaining raw coal (RC) is provided.

<Solvent supply unit for extraction>
The extraction solvent supply unit 2 supplies the extraction solvent to the mixing unit 6. As shown in FIG. 1, the extraction solvent supply unit 2 mainly includes an extraction solvent tank 10 and an extraction solvent pressure feed pump 11.

(Solvent tank for extraction)
The extraction solvent tank 10 stores the extraction solvent to be mixed with the pasted coal supplied from the pasted coal supply unit 5. The extraction solvent to be mixed with the pasted coal is not particularly limited as long as it dissolves coal. For example, a bicyclic aromatic compound derived from coal is preferably used. Since this bicyclic aromatic compound has a basic structure similar to the structural molecule of coal, it has a high affinity with coal and can obtain a relatively high extraction rate. Examples of the bicyclic aromatic compound derived from coal include methyl naphthalene oil and naphthalene oil, which are distilled oils of by-products when carbon is produced by carbonization to produce coke.

  The boiling point of the extraction solvent is not particularly limited. For example, the lower limit of the boiling point of the extraction solvent is preferably 180 ° C, more preferably 230 ° C. On the other hand, the upper limit of the boiling point of the extraction solvent is preferably 300 ° C, and more preferably 280 ° C. If the boiling point of the extraction solvent is less than the above lower limit, the loss due to volatilization increases when the extraction solvent is recovered in the solvent evaporation separation process, which will be described later, and the recovery rate of the extraction solvent decreases. There is a risk. Conversely, when the boiling point of the extraction solvent exceeds the above upper limit, it is difficult to separate the solvent-soluble component from the extraction solvent, and in this case, the recovery rate of the extraction solvent may be reduced.

(Extraction solvent pump)
The extraction solvent pumping pump 11 is disposed in a line connecting the extraction solvent tank 10 to the mixing unit 6. The extraction solvent pumping pump 11 pumps the extraction solvent stored in the extraction solvent tank 10 to the mixing unit 6 via the main supply pipe 19.

  The type of the solvent pump for extraction 11 is not particularly limited as long as the solvent for extraction can be pumped to the mixing unit 6 via the main supply pipe 19, but for example, a positive displacement pump or a non-positive displacement pump is used. Can do. More specifically, a diaphragm pump or a tube diaphragm pump can be used as the positive displacement pump, and a spiral pump or the like can be used as the non-positive displacement pump.

  Note that the extraction solvent may be pumped through the main supply pipe 19 in a turbulent state by the extraction solvent pumping pump 11. By mixing the extraction solvent with the pasted coal in a turbulent state, the extraction solvent collides violently with the pasted coal supplied from the pasted coal supply unit 5, and the coal dissolves faster. Thereby, the extraction time is further shortened and the extraction rate is further improved. Here, the “turbulent flow state” is, for example, a state where the Reynolds number Re is 2100 or more, and more preferably a state where the Reynolds number Re is 4000 or more.

<Heating section>
The heating unit 3 heats the extraction solvent pumped by the extraction solvent pumping pump 11. The heating unit 3 is not particularly limited as long as it can heat the extraction solvent, but a heat exchanger is generally used as the heating unit 3. When a heat exchanger is used as the heating unit 3, the extraction solvent flowing in the pipe is heated by exchanging heat when passing through the heating unit 3. As the heat exchanger used as the heating unit 3, for example, a heat exchanger such as a multi-tube type, a plate type, or a spiral type is used. In the ashless coal production apparatus 1 shown in FIG. 1, the heating unit 3 is disposed downstream of the extraction solvent pumping pump 11 of the extraction solvent supply unit 2, and the extraction solvent pumping pump 11 Although the extraction solvent that has been pumped is heated, the extraction solvent previously heated by the heating unit 3 may be pumped by the extraction solvent pumping pump 11. That is, the arrangement of the extraction solvent pressure pump 11 and the heating unit 3 in FIG. 1 may be reversed.

  Here, the temperature of the slurry (the above extraction temperature) at which a high extraction rate is obtained in the mixing unit 6 is about 300 ° C. or higher and 420 ° C. or lower. Therefore, it is preferable to supply to the mixing unit 6 an extraction solvent having a temperature such that the slurry mixed with the pasted coal in the mixing unit 6 has this extraction temperature. Since the temperature of the extraction solvent is lowered by mixing with the pasted coal, the extraction solvent is preferably heated to a temperature higher than the temperature of the slurry in the mixing unit 6. From this viewpoint, the lower limit of the temperature of the extraction solvent downstream of the heating unit 3 is preferably 330 ° C, and more preferably 380 ° C. On the other hand, the upper limit of the temperature of the extraction solvent is preferably 450 ° C and more preferably 430 ° C. When the temperature of the extraction solvent is lower than the lower limit, the slurry in which the extraction solvent and pasted coal are mixed in the mixing unit 6 is hardly heated to the extraction temperature, and bonds between molecules constituting the coal are reduced. There is a possibility that the extraction rate is not sufficiently reduced. On the other hand, if the temperature of the extraction solvent exceeds the upper limit, the temperature of the slurry becomes too high in the mixing unit 6 and recombination of pyrolysis radicals generated by the pyrolysis reaction of coal occurs, so the extraction rate decreases. There is a risk. The temperature of the extraction solvent downstream of the heating unit 3 means the temperature of the extraction solvent at the outlet of the heating unit 3.

  The heating unit 3 heats the extraction solvent flowing in the main supply pipe 19 to a temperature in the above range while passing through the heating unit 3. Although the heating time in the heating part 3 is not specifically limited, For example, it is 10 minutes or more and 30 minutes or less. Further, the extraction solvent is preheated using waste heat in order to increase thermal efficiency, and the temperature of the extraction solvent before passing through the heating unit 3 is about 100 ° C. Accordingly, it is preferable that the heating unit 3 can heat the extraction solvent at a heating rate of about 10 ° C. to 100 ° C. per minute. Note that the extraction solvent may not be preheated before passing through the heating unit 3.

  Moreover, it is preferable that the said heating part 3 heats the solvent for extraction under high pressure. Although it depends on the vapor pressure of the extraction solvent, the lower limit of the pressure when the heating unit 3 heats the extraction solvent is preferably 1 MPa and more preferably 2 MPa. On the other hand, the upper limit of the pressure is preferably 5 MPa, more preferably 4 MPa. If the pressure when the heating unit 3 heats the extraction solvent is less than the lower limit, the extraction solvent volatilizes, and it may be difficult to extract the solvent-soluble component in a slurry acquisition step described later. On the other hand, when the said pressure exceeds the said upper limit, there exists a possibility that an installation cost and an operating cost may increase.

<Preparation part>
The preparation unit 4 obtains pasted coal by mixing a pasting solvent and coal. The preparation unit 4 is a mixer, and a predetermined amount of coal and a pasting solvent are charged into the mixer, and the mixer stirs and mixes to obtain pasted coal. The mixer used here is not particularly limited as long as it corresponds to high viscosity, and for example, a mortar mixer, a concrete mixer or the like can be used. Although it is considered that the time for stirring and mixing is longer, it is preferably about 1 hour to 3 hours from the viewpoint of production efficiency.

  Various types of coal can be used as the coal to be mixed with the pasting solvent. For example, bituminous coal with a high extraction rate or cheaper inferior quality coal (subbituminous coal or lignite) is preferably used. Further, when coal is classified by particle size, finely pulverized coal is preferably used. Here, “finely pulverized coal” means, for example, coal in which the mass ratio of coal having a particle size of less than 1 mm to the mass of the entire coal is 80% or more. Alternatively, lump coal can be used as the coal mixed with the pasting solvent in the pasting coal supply unit 5. Here, the “coal” means coal having a mass ratio of coal having a particle size of 5 mm or more to the mass of the whole coal of 50% or more. Since the coal lump has a larger coal particle size than finely pulverized coal, the separation speed in the solution separation step described later is increased, and the sedimentation separation can be made more efficient. Here, the “particle diameter” refers to a value measured in accordance with the screening test general rules of JIS-Z8815 (1994). In addition, the metal net sieve prescribed | regulated to JIS-Z8801-1 (2006) can be used for the classification by the particle size of coal, for example.

  The lower limit of the content of particles having a particle size of 1 mm or less of coal mixed with the pasting solvent is preferably 5% by mass, and more preferably 10% by mass. The finer the particle size of the coal, the better. The content may be 100% by mass or less. When the content is less than the lower limit, it is difficult to mix with the solvent for pasting, and the preparation time for pasting coal may be long.

  Although the said solvent for pasting is not specifically limited, The solvent which is easy to isolate | separate ashless coal and byproduct coal from the supernatant liquid isolate | separated by the solid-liquid separation part 7 mentioned later and solid content concentrated liquid is preferable. Specifically, for example, a bicyclic aromatic compound derived from coal is preferably used as the solvent for pasting. Examples of the bicyclic aromatic compound derived from coal include methyl naphthalene oil and naphthalene oil, which are distilled oils of by-products when carbon is produced by carbonization to produce coke. Further, as the pasting solvent, it is particularly preferable to use the same type of solvent as the extraction solvent supplied from the extraction solvent supply unit 2 from the viewpoint of reuse of the solvent.

  As a minimum of coal concentration (anhydrous carbon basis) in the above-mentioned pasted coal, 40 mass% is preferred and 50 mass% is more preferred. On the other hand, the upper limit of the coal concentration is preferably 70% by mass, and more preferably 60% by mass. When the coal concentration is less than the lower limit, the proportion of the pasting solvent contained in the pasted coal is too high, and the pasted coal is not sufficiently heated when mixed with the heated extraction solvent, There is a possibility that sufficient extraction speed shortening effect cannot be obtained. On the other hand, when the coal concentration exceeds the upper limit, the bonding force between the coal in the pasted coal and the pasting solvent is weak and difficult to mix with the extraction solvent supplied from the extraction solvent supply unit 2. There is a possibility that the temperature rise rate of the modified coal becomes slow and a sufficient effect of shortening the extraction rate cannot be obtained.

  The lower limit of the ratio of the mass of the pasting solvent contained in the pasting coal supplied from the pasting coal supply unit 5 to the mass of the extraction solvent fed through the main supply pipe 19 is preferably 1/20. On the other hand, the upper limit of the ratio is preferably 1, and more preferably 1/2. If the ratio is less than the lower limit, the coal concentration in pasted coal must be increased, and the preparation time of pasted coal may be increased. On the contrary, when the ratio exceeds the upper limit, the ratio of the pasting solvent contained in the pasted coal is excessively increased with respect to the heated extraction solvent, and is mixed with the heated extraction solvent. There is a possibility that the temperature of the pasted coal is not sufficiently raised, and a sufficient extraction speed shortening effect cannot be obtained.

  The lower limit of the viscosity of the pasted coal at 30 ° C. is preferably 0.5 Pa · s, and more preferably 1 Pa · s. On the other hand, the upper limit of the viscosity is preferably 1000 Pa · s, and more preferably 600 Pa · s. When the viscosity is less than the lower limit, the pasting coal contains too much proportion of the pasting solvent, and the pasting coal is not sufficiently heated when mixed with the heated extraction solvent. There is a possibility that the effect of shortening the extraction speed cannot be obtained. Conversely, if the viscosity exceeds the upper limit, the main supply pipe may be easily clogged with pasted coal.

<Pasted coal supply unit>
The pasted coal supply unit 5 supplies the pasted coal obtained in the preparation unit 4 to the mixing unit 6. The pasted coal supply unit 5 includes a pasted coal hopper 12 that stores pasted coal supplied from the preparation unit 4, a pasted coal supply pipe 13 that connects the pasted coal hopper 12 and the main supply pipe 19, and a paste. A first valve 14 and a second valve 15 are provided on the activated coal supply pipe 13. Between the first valve 14 and the second valve 15 of the pasted coal supply pipe 13, a pressurization line 16 for supplying a gas such as nitrogen gas and an exhaust line 17 for exhausting the gas are connected. .

  The pasted coal supplied to the pasted coal hopper 12 is first filled in the pasted coal supply pipe 13 by opening the first valve 14 with the second valve 15 closed. Next, the first valve 14 is closed, and a gas such as nitrogen gas is supplied to the pasted coal supply pipe 13 via the pressurization line 16, and the first valve 14 and the second valve 15 of the pasted coal supply pipe 13 are supplied. Then, pressure is applied to pasted coal filled between and the pressure line 16 is closed. As a result, the pasted coal filled between the first valve 14 and the second valve 15 of the pasted coal supply pipe 13 is pressurized to a pressure higher than that of the main supply pipe 19. Then, by opening the second valve 15, the pasted coal filled in the pasted coal supply pipe 13 flows into the main supply pipe 19 vigorously. At this time, after the pasted coal filled between the first valve 14 and the second valve 15 passes through the second valve 15, the second valve 15 is closed and the valve of the exhaust line 17 is opened. Then, the gas in the pasted coal supply pipe 13 is exhausted. Then, after exhausting the gas in the pasted coal supply pipe 13, the valve of the exhaust line 17 is closed.

  By repeating the operations of the first valve 14, the second valve 15, the pressurization line 16 and the exhaust line 17 as described above, the pasted coal stored in the pasted coal hopper 12 is intermittently supplied to the main supply pipe. 19 can be supplied. The volume in the pasted coal supply pipe 13 and the operation of the first valve 14, the second valve 15, the pressurization line 16 and the exhaust line 17 are adjusted according to the flow rate and flow rate of the extraction solvent pumped in the main supply pipe 19. By setting the timing, it is possible to intermittently supply a predetermined amount of pasted coal while continuing to supply the extraction solvent by the extraction solvent supply unit 2.

  Here, the types of the first valve 14 and the second valve 15 are not particularly limited. As the first valve 14 and the second valve 15, for example, a gate valve, a ball valve, a flap valve, a rotary valve, and the like can be used. Can be used.

<Mixing section>
The mixing unit 6 obtains a slurry by mixing the extraction solvent supplied from the extraction solvent supply unit 2 and the pasted coal supplied from the pasted coal supply unit 5. The mixing unit 6 has an extraction tank 18.

(Extraction tank)
The extraction tank and the pasted coal are supplied to the extraction tank 18 through a main supply pipe 19. The extraction tank 18 mixes the supplied extraction solvent and pasted coal into a slurry, and stores this slurry for a predetermined time.

  The extraction tank 18 has a stirrer 18a. The extraction tank 18 extracts the solvent-soluble component by holding the mixed slurry at a predetermined temperature while stirring with the stirrer 18a.

  The extraction solvent pumped in the main supply pipe 19 is heated by the heating unit 3 and has a high temperature, and the amount of the extraction solvent pumped in the main supply pipe 19 is from the pasted coal supply unit 5. By reducing the amount of pasting solvent contained in the supplied pasted coal, the pasted coal supplied from the pasted coal supply unit 5 is rapidly heated in the main supply pipe 19. Here, “rapid temperature rise” means heating at a heating rate of 10 ° C. or more and 500 ° C. or less per second, for example, and is faster than the heating rate in the heating unit 3. Further, the extraction solvent flowing in the main supply pipe 19 is heated to a temperature higher than the extraction temperature, but when it comes into contact with the pasted coal, the heat of the extraction solvent is used to increase the temperature of the pasted coal. The temperature of the extraction solvent supplied to the extraction tank 18 is lower than the temperature of the extraction solvent heated in the heating unit 3. As a result, when the extraction solvent and pasted coal move through the main supply pipe 19 to the extraction tank 18, the temperatures of the extraction solvent and pasted coal are both at the extraction temperature (about 300 ° C to 420 ° C). It changes to approach. As a result, the slurry in the extraction tank 18 in which the extraction solvent and the pasted coal are mixed has the above extraction temperature.

  As a minimum of the retention temperature of the slurry in the said extraction tank 18, 300 degreeC is preferable and 350 degreeC is more preferable. On the other hand, the upper limit of the holding temperature of the slurry is preferably 420 ° C., more preferably 400 ° C. When the holding temperature of the slurry is less than the lower limit, the bond between the molecules constituting the coal cannot be sufficiently weakened, and the extraction rate may be reduced. On the other hand, when the holding temperature of the slurry exceeds the upper limit, coal pyrolysis reaction becomes very active and recombination of generated pyrolysis radicals occurs, which may reduce the extraction rate.

  In addition, it is preferable to perform the heat extraction of the slurry in the extraction tank 18 in a non-oxidizing atmosphere. Specifically, it is preferable to perform heat extraction of the slurry in the presence of an inert gas such as nitrogen. By using an inert gas such as nitrogen, it is possible to prevent the slurry from coming into contact with oxygen and igniting at low cost during the heat extraction.

  The pressure during the heat extraction of the slurry depends on the heating temperature and the vapor pressure of the extraction solvent to be used, but can be, for example, 1 MPa or more and 3 MPa or less. When the pressure at the time of heat extraction is lower than the vapor pressure of the extraction solvent, the extraction solvent may volatilize and the solvent-soluble component may not be sufficiently extracted. On the other hand, if the pressure at the time of heating extraction is too high, the cost of the equipment, the operating cost, etc. increase.

  As a minimum of coal concentration on the basis of anhydrous coal in the slurry in extraction tank 18, 10 mass% is preferred and 13 mass% is more preferred. On the other hand, the upper limit of the coal concentration is preferably 25% by mass, and more preferably 20% by mass. When the said coal concentration is less than the said minimum, the extraction amount of the said solvent soluble component decreases, and there exists a possibility that the manufacture efficiency of ashless coal with respect to the quantity of a solvent may fall. On the contrary, when the coal concentration exceeds the upper limit, the solvent-soluble component is saturated in the solvent, so that the extraction rate of the solvent-soluble component may be reduced. Therefore, the ratio of the amount of coal to the total amount of the pasting solvent contained in the pasting coal supplied from the pasting coal supply unit 5 and the extraction solvent supplied from the extraction solvent supply unit 2 is the above coal. It is preferable to supply the extraction solvent in an amount within the concentration range from the extraction solvent supply unit 2.

<Solid-liquid separation unit>
The solid-liquid separation unit 7 separates the solution in which the solvent-soluble component is dissolved from the slurry mixed in the mixing unit 6.

  The separation of the solution in the solid-liquid separation unit 7 is specifically performed by a gravity sedimentation method and a solution in which a solvent-soluble component is dissolved from a slurry in which an extraction solvent and pasted coal are mixed in the mixing unit 6 and a solvent-insoluble component. Into a solid concentrate containing Here, the gravity sedimentation method is a separation method in which a solid content is settled using gravity to separate the solid and the liquid. The solvent-insoluble component is an extraction residue that is mainly composed of ash and insoluble coal that are insoluble in the extraction solvent, and also includes the extraction solvent.

  The ashless coal production apparatus 1 discharges a solution containing a solvent-soluble component from the upper part while continuously supplying slurry into the solid-liquid separation unit 7, and a solid content concentrate containing a solvent-insoluble component from the lower part. Can be discharged. Thereby, continuous solid-liquid separation processing becomes possible.

  The solution containing the solvent-soluble component accumulates at the top of the solid-liquid separation unit 7. This solution is filtered through a filter unit (not shown) as necessary, and then discharged to the first solvent separation unit 8. On the other hand, the solid concentrate containing the solvent-insoluble component is collected at the lower part of the solid-liquid separation unit 7 and discharged to the second solvent separation unit 9.

  Although the time which maintains a slurry in the solid-liquid separation part 7 is not specifically limited, For example, it is 30 minutes or more and 120 minutes or less, and sedimentation separation in the solid-liquid separation part 7 is performed within this time. In addition, when using lump coal as coal mixed with pasted coal, since sedimentation separation is made efficient, the time which maintains a slurry in the solid-liquid separation part 7 can be shortened.

  The inside of the solid-liquid separation unit 7 is preferably heated and pressurized. As a minimum of heating temperature in solid-liquid separation part 7, 300 ° C is preferred and 350 ° C is more preferred. On the other hand, as an upper limit of the heating temperature in the solid-liquid separation part 7, 420 degreeC is preferable and 400 degreeC is more preferable. If the heating temperature is less than the lower limit, the solvent-soluble component may reprecipitate and the separation efficiency may be reduced. Conversely, if the heating temperature exceeds the upper limit, the operating cost for heating may increase.

  Moreover, as a minimum of the pressure in the solid-liquid separation part 7, 1 MPa is preferable and 1.4 MPa is more preferable. On the other hand, the upper limit of the pressure is preferably 3 MPa, more preferably 2 MPa. If the pressure is less than the lower limit, the solvent-soluble component may reprecipitate and the separation efficiency may be reduced. Conversely, when the pressure exceeds the upper limit, the operating cost for pressurization may increase.

  In addition, as a method of isolate | separating the said solution and solid content concentrate, it is not restricted to a gravity sedimentation method, For example, you may use the filtration method and the centrifugation method. When a filtration method or a centrifugation method is used as the solid-liquid separation method, a filter, a centrifuge, or the like is used as the solid-liquid separation unit 7.

<First solvent separation unit>
The first solvent separation unit 8 evaporates and separates the extraction solvent and the pasting solvent from the solution separated by the solid-liquid separation unit 7 to obtain ashless coal (HPC).

  Here, as a method for evaporating and separating the extraction solvent and the pasting solvent, a separation method including a general distillation method or an evaporation method (spray drying method or the like) can be used. The solvent for extraction and the solvent for pasting recovered by separation can be circulated to a pipe upstream of the heating unit 3 and repeatedly used. By separating and recovering the extraction solvent and the pasting solvent from the solution, ashless coal substantially free of ash can be obtained from the solution.

  The ashless coal thus obtained has an ash content of 5% by mass or less or 3% by mass or less, hardly contains ash, has no moisture, and exhibits a higher calorific value than, for example, raw coal. Furthermore, ashless coal has a significantly improved softening and melting property, which is a particularly important quality as a raw material for iron-making coke, and exhibits fluidity far superior to, for example, raw material coal. Therefore, ashless coal can be used as a blended coal for coke raw materials.

<Second solvent separation unit>
The second solvent separation unit 9 evaporates and separates the extraction solvent and the pasting solvent from the solid concentrate separated by the solid-liquid separation unit 7 to obtain by-product coal (RC).

  Here, as a method for separating the extraction solvent and the pasting solvent from the solid concentrate, a general distillation method or evaporation method (spray drying method or the like) is used as in the separation method of the first solvent separation unit 8. be able to. The solvent for extraction and the solvent for pasting recovered by separation can be circulated to a pipe upstream of the heating unit 3 and repeatedly used. By separating and recovering the extraction solvent and the pasting solvent, by-product charcoal in which solvent-insoluble components including ash and the like are concentrated from the solid concentrate can be obtained. By-product charcoal does not show softening and melting properties, but the oxygen-containing functional groups are eliminated. Therefore, by-product coal does not inhibit the softening and melting properties of other coals contained in this blended coal when used as a blended coal. Therefore, this blended coal can also be used as a part of the blended coal of the coke raw material. The coal blend may be discarded without being collected.

[Production method of ashless coal]
The method for producing ashless coal includes a step of heating an extraction solvent (solvent heating step), a step of obtaining pasted coal by mixing a pasting solvent and coal (pasting coal acquisition step), and the above extraction method A step of obtaining a slurry by mixing the solvent and pasted coal (slurry obtaining step), a step of separating the solution in which the coal component is dissolved from the slurry (solution separation step), the extraction solvent from the separated solution, and A step of evaporating and separating the solvent for pasting (solvent evaporating and separating step), a step of obtaining by-product coal by evaporating and separating the solvent from the solid concentrate separated in the solution separating step (by-product coal obtaining step), Is provided. The slurry acquisition step includes a step of supplying an extraction solvent (solvent supply step) and a step of pumping pasted coal (pumping step). Hereinafter, the manufacturing method of the said ashless coal using the ashless coal manufacturing apparatus 1 of FIG. 1 is demonstrated.

<Solvent heating process>
In the solvent heating step, the extraction solvent is heated. Specifically, the extraction solvent flowing in the pipe is heated to a temperature higher than the extraction temperature by the heating unit 3 disposed in a line connecting the extraction solvent tank 10 and the mixing unit 6. As a result, the heated extraction solvent is supplied to the mixing unit 6 via the main supply pipe 19.

<Pasted coal acquisition process>
In the pasted coal acquisition step, pasted coal is obtained by mixing a pasting solvent and coal. Specifically, using a mixer as the preparation unit 4, a predetermined amount of coal and a pasting solvent are charged into the mixer and mixed by stirring to obtain pasted coal.

<Slurry acquisition process>
In the slurry acquisition step, the extraction solvent and pasted coal are mixed to obtain a slurry. The slurry acquisition process includes a solvent supply process and a pumping process.

(Solvent supply process)
In the solvent supply step, the extraction solvent is supplied to the mixing unit 6. Specifically, the extraction solvent stored in the extraction solvent tank 10 is pumped to the mixing unit 6 through the main supply pipe 19 by the extraction solvent pumping pump 11. In order to facilitate the mixing of the extraction solvent and pasted coal, the extraction solvent supplied to the mixing unit 6 by the extraction solvent pump 11 is pumped through the main supply pipe 19 in a turbulent state to be mixed with the pasted coal. May be.

(Pressing process)
In the pumping step, the pasted coal obtained in the pasted coal obtaining step is supplied to the mixing unit 6 via the main supply pipe 19. Specifically, by repeating the operations of the first valve 14, the second valve 15, the pressurization line 16 and the exhaust line 17 described above, a predetermined amount of pasted coal supplied to the pasted coal hopper 12 is pressurized. And intermittently pumped to the mixing section 6 via the main supply pipe 19.

  Then, the extraction solvent and pasted coal supplied in the solvent supply step and the pressure feeding step are mixed in the extraction tank 18 to form a slurry. Further, the slurry is held at the extraction temperature for a predetermined time in the extraction tank 18 to extract the solvent-soluble component. When the extraction solvent and the pasted coal are supplied to the extraction tank 18, the pasted coal is rapidly heated by the heated extraction solvent, and the slurry in which the extraction solvent and the pasted coal are mixed becomes the extraction temperature. . Thereby, the solvent-soluble component is rapidly extracted in the extraction tank 18.

<Solution separation process>
In the solution separation step, the solution in which the solvent-soluble component is dissolved and the solid concentration liquid containing the solvent-insoluble component are separated from the slurry mixed in the slurry acquisition step. Specifically, the slurry discharged from the extraction tank 18 is supplied, and the slurry supplied by, for example, the gravity sedimentation method in the solid-liquid separation unit 7 is separated into the solution and the solid concentrate.

<Solvent evaporation separation process>
In the solvent evaporation separation step, the extraction solvent and the pasting solvent are evaporated and separated from the solution separated in the solution separation step to obtain ashless coal. Specifically, the solution separated in the solid-liquid separation unit 7 is supplied to the first solvent separation unit 8, and the extraction solvent and the pasting solvent are evaporated in the first solvent separation unit 8 to obtain a solvent and ashless coal. And to separate.

<By-product coal acquisition process>
In the byproduct charcoal acquisition step, byproduct charcoal is obtained by evaporation separation from the solid content concentrate separated in the solution separation step. Specifically, the solid concentrate separated by the solid-liquid separation unit 7 is supplied to the second solvent separation unit 9, and the extraction solvent and the pasting solvent are evaporated by the second solvent separation unit 9. Separated into by-product charcoal.

<Advantages>
Since the ashless coal manufacturing apparatus mixes the heated extraction solvent and pasted coal, the pasted coal is quickly mixed with the heated extraction solvent. Further, by reducing the amount of pasting solvent contained in pasted coal relative to the amount of extracting solvent, the slurry in which these extracting solvent and pasted coal are mixed can be rapidly added to the solvent-soluble component. The temperature can be easily extracted. Thereby, a solvent soluble component is extracted rapidly and the manufacturing apparatus of the said ashless coal can shorten the extraction time of a solvent soluble component.

  Moreover, since the said ashless coal manufacturing apparatus mixes pasted coal with the heated extraction solvent, compared with the case where coal is directly mixed with the heated extraction solvent, coal is easy to mix with the extraction solvent. The time required for mixing is short. As a result, the slurry is quickly mixed with coal and the extraction solvent, and extraction of the solvent-soluble component starts, so that the extraction time is shortened and the processing time of the entire ashless coal manufacturing process can be shortened.

  In addition, the ashless coal production apparatus does not heat the slurry in which the extraction solvent and coal are mixed as in the conventional ashless coal production apparatus, but only the extraction solvent is heated. The pasted coal is heated by mixing with pasted coal. Since the extraction solvent is easier to handle than the slurry, and heating only the extraction solvent is easier than heating the slurry, the ashless coal production apparatus is excellent in handling in this respect.

[Second Embodiment]
The ashless coal production apparatus 21 in FIG. 2 is different from the ashless coal production apparatus 1 in FIG. 1 in the configuration of a pasted coal supply unit 22 that supplies pasted coal to the main supply pipe 19. The ashless coal production apparatus 21 has the same configuration as the ashless coal production apparatus 1 of FIG. 1 except that the configuration of the pasted coal supply unit 22 is different. The reference numerals are attached and the description is omitted.

<Pasted coal supply unit>
The pasted coal supply unit 22 includes a pasted coal hopper 12 that stores pasted coal and a pasted coal pressure pump 23.

  The pasted coal hopper 12 is supplied with pasted coal obtained by stirring and mixing the pasting solvent and coal in the preparation unit 4 as in the ashless coal manufacturing apparatus 1.

  The pasted coal pumping pump 23 is disposed between the pasted coal hopper 12 and the main supply pipe 19, and continuously pumps the pasted coal in the pasted coal hopper 12 to the main supply pipe 19.

  The pasted coal pressure pump 23 is not particularly limited as long as it can pump a highly viscous fluid. For example, a Mono pump, a sine pump, a diaphragm pump, a bellows pump, a rotary pump, or the like can be used. Among these pumps, the MONO pump is particularly preferable in that the efficiency does not decrease even when the viscosity of the fluid increases.

<Advantages>
The mixing section of the ashless coal production device and the main supply pipe connected to it have high pressure, but the ashless coal production device uses pasted coal as the coal raw material to be supplied. The supply pressure of the coal raw material can be controlled by the pump without being affected by the pressure difference with the pipe. When powder coal is supplied as a raw material for coal, it is difficult to control the amount of coal supplied by a pump because of the large influence of the pressure difference. The supply amount can be easily controlled, and stable raw material coal can be supplied.

  Moreover, since the said ashless-coal manufacturing apparatus pumps pasted coal continuously with a pump, it can adjust the pressure which supplies pasted coal easily with low equipment cost. Moreover, the deterrent effect of the main supply pipe etc. being blocked by pasted coal can be enhanced.

[Other Embodiments]
In addition, the manufacturing apparatus of ashless coal and the manufacturing method of ashless coal of this invention are not limited to the said embodiment.

  That is, in the above embodiment, the pasted coal supply unit has been described as supplying the pasted coal to the mixing unit via the main supply pipe, but the pasted coal supply unit directly supplies the pasted coal to the mixing unit. May be. Thus, even when the pasted coal supply unit directly supplies pasted coal to the mixing unit without going through the main supply pipe, the pasted coal is heated in the mixing unit to the mixing unit. So that the solvent-soluble component is rapidly extracted.

  In the above embodiment, the configuration in which the mixing unit has the extraction tank has been described. However, the present invention is not limited to this configuration, and the extraction tank is omitted if the extraction solvent and pasted coal can be mixed and the solvent-soluble component can be extracted. May be. For example, when the extraction time is short and the mixing and extraction are completed by a line mixer, the extraction tank may be omitted and a line mixer may be provided between the main supply pipe and the solid-liquid separation unit.

  Moreover, in the said embodiment, although demonstrated as a pasted coal being prepared with a mixer, you may prepare a pasted coal in a pasted coal hopper. For example, an agitator may be provided in the pasted coal hopper, and the pasting coal may be prepared in the pasted coal hopper by supplying the pasting solvent and coal to the pasted coal hopper.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

(Example 1)
The pasted coal with a coal concentration of 50% by mass on the basis of anhydrous coal is prepared by mixing coal and a solvent (viscosity at 0.005 Pa at 30 ° C.), and the top of the autoclave container 31 having a capacity of 500 cc shown in FIG. The pasted coal was charged in a normal temperature state into a pipe 36 connected to. On the other hand, a solvent of the same type as the solvent used for the preparation of the pasted coal was placed in the container 31, and the solvent in the container 31 was heated to the extraction temperature (380 ° C.) or higher by the heater 35 under a pressure of 2.0 MPa. . Then, by opening the two valves 37 and 38 provided in the pipe 36 and introducing nitrogen gas into the pipe 36, the pasted coal in the pipe 36 is dropped into the solvent, and the pasted coal is extracted instantly. The temperature was raised to 380 ° C. And the solvent soluble component was extracted over 60 minutes of extraction time.

(Comparative Example 1)
A slurry obtained by mixing coal and a solvent (viscosity at 30 ° C. of 0.005 Pa · s) is put into the container 31 of FIG. 3, and the heater 35 is stirred with a stirrer 34 under a pressure of 2.0 MPa. Was increased to the extraction temperature (380 ° C.). And after heating up slurry to extraction temperature, the solvent soluble component was extracted over 60 minutes of extraction time. In addition, the coal concentration in the slurry in Example 1 and Comparative Example 1 is the same including the solvent used for converting the coal into pasted coal in Example 1 (coal concentration of 13.8% by mass on the basis of anhydrous coal). It was made to become.

[Solvent-soluble component extraction evaluation]
For Example 1 and Comparative Example 1, the extraction rate of the solvent-soluble component was calculated as follows, and the extraction rate of the solvent-soluble component was evaluated.

  After extracting the solvent-soluble component in Example 1 and Comparative Example 1, the valve 32 provided in the pipe connected to the bottom of the container 31 was opened, the slurry was filtered hot with the filter 33, and the filtrate was filtered with the receiver 39. I received it. And the filter residual mass on the filter 33 was measured and the extraction rate was computed. In addition, the said extraction rate is the ratio of the anhydrous ashless base of the solvent-soluble component extracted with respect to the anhydrous ashless base (daf) of the coal used for the said paste-ized coal. Here, the said extraction rate was computed as the anhydrous ashless base of the solvent-soluble component which extracted the thing which reduced the anhydrous ashless base of the filter residue from the anhydrous ashless base of the coal used for the said paste-ized coal. In this way, the extraction rates at extraction times of 10, 20, and 60 minutes were calculated.

  The relationship between the extraction time and the extraction rate in Example 1 and Comparative Example 1 is shown in the graph of FIG. Here, the extraction time was measured from the time when the pasted coal in the container 31 reached the extraction temperature (380 ° C.). In Example 1, the temperature of the slurry reaches the extraction temperature several seconds after dropping the pasted coal, and in Comparative Example 1, the temperature of the slurry is extracted about 1 hour after the slurry in the container 31 starts to be heated by the heater 35. The temperature has been reached.

  4, the extraction rate when the extraction time is 20 minutes in Example 1 (58.9 mass% daf), the extraction rate when the extraction time is 60 minutes in Comparative Example 1 ( 59.5 mass% daf)). That is, when extracting solvent-soluble components having the same extraction rate by the heating methods of Example 1 and Comparative Example 1, it can be said that Example 1 can be extracted in a shorter time than Comparative Example 1. From this, it can be seen that the extraction rate is increased by rapidly raising the temperature of coal as in Example 1.

  Moreover, when the extraction rate in the same extraction time (60 minutes) is compared, the extraction rate of Example 1 (61.0 mass% daf) is higher than that of Comparative Example 1 (59.5 mass%). d.af)). Thereby, the extraction rate in the same time improves by raising the temperature of coal mixed like Example 1 rapidly.

  As described above, the ashless coal production method and the ashless coal production apparatus can shorten the extraction time of the solvent-soluble component, and thus can efficiently obtain ashless coal from coal.

DESCRIPTION OF SYMBOLS 1 Ashless coal manufacturing apparatus 2 Extraction solvent supply part 3 Heating part 4 Preparation part 5 Paste coal supply part 6 Mixing part 7 Solid-liquid separation part 8 1st solvent separation part 9 2nd solvent separation part 10 Solvent tank for extraction 11 Extraction solvent pressure pump 12 Paste coal hopper 13 Paste coal supply pipe 14 First valve 15 Second valve 16 Pressurization line 17 Exhaust line 18 Extraction tank 18a Stirrer 19 Main supply pipe 21 Ashless coal production device 22 Pasteing Coal supply unit 23 Paste coal pump 31 Container 32 Valve 33 Filter 34 Stirrer 35 Heater 36 Pipe 37, 38 Valve 39 Receiver

Claims (9)

Heating the extraction solvent;
A step of obtaining pasted coal by mixing a pasting solvent and coal;
A step of obtaining a slurry by mixing the extraction solvent and pasted coal;
Separating the solution in which the coal component is dissolved from the slurry;
And a step of evaporating and separating the extraction solvent and the pasting solvent from the separated solution.   The method for producing ashless coal according to claim 1, wherein in the heating step, the temperature of the extraction solvent is set to 330 ° C or higher and 450 ° C or lower.   The manufacturing method of the ashless coal of Claim 1 or Claim 2 which makes the density | concentration of the coal in paste-ized coal 40 mass% or more and 70 mass% or less by the said paste-ized coal acquisition process.   4. The method for producing ashless coal according to claim 1, wherein the extraction solvent is mixed with pasted coal in a turbulent state in the slurry obtaining step. 5.   The method for producing ashless coal according to any one of claims 1 to 4, wherein the slurry obtaining step includes a step of pumping pasted coal into the extraction solvent.   The method for producing ashless coal according to claim 5, wherein in the pumping step, a predetermined amount of pasted coal is pressurized and intermittently pumped.   The method for producing ashless coal according to claim 5, wherein in the pumping step, the pasted coal is continuously pumped by a pump. A heating section for heating the extraction solvent;
A preparation unit for obtaining pasted coal by mixing a pasting solvent and coal;
A mixing section for obtaining a slurry by mixing the extraction solvent and pasted coal;
A solid-liquid separation unit for separating the solution in which the coal component is dissolved from the slurry;
An apparatus for producing ashless coal, comprising: a solvent separation unit that evaporates and separates the extraction solvent and the pasting solvent from the solution separated by the solid-liquid separation unit.   The ashless coal manufacturing apparatus according to claim 8, wherein the mixing unit has an extraction tank for storing the slurry.

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