JP2011149623A - Coal-water paste manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coal-water paste manufacturing device which manufactures the coal-water paste with the viscosity controlled at a further constant level compared with a conventional coal-water paste manufacturing device. <P>SOLUTION: The coal-water paste manufacturing device includes: a kneading machine 3; a pulverized coal slurry manufacturing device 7 having a coal feeder 39 with a moisture meter 43 measuring a moisture amount of pulverized coal online and a pulverized coal slurry viscosity measuring device 49; a coal feeder 9 having a moisture meter 23 measuring a moisture amount of pulverized coal supplied to the kneading machine 3 online; a kneading machine water filling device 11 supplying water for controlling the viscosity to the kneading machine 3; a viscosity measuring device 5 measuring the CWP viscosity at the outlet of the kneading machine 3 online; and a control device 13 controlling a water filling amount to a pulverizing mill 37 and the water filling amount to the kneading machine 3. By supplying the pulverized coal slurry with the viscosity controlled at a constant level to the kneading machine 3, the coal and water paste with the viscosity controlled at a further constant level can be manufactured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coal / water paste production apparatus for producing coal / water paste which is fuel for a pressurized fluidized bed boiler.

  In a power generation system using a pressurized fluidized bed boiler, a combined power generation system that generates steam by generating heat by combustion heat generated by burning coal and driving a steam turbine and driving a gas turbine with combustion gas is adopted. Since the pressurized fluidized bed boiler fluidizes the fluid medium in the boiler and combusts the supplied coal while fluidizing it, the combustion temperature is as low as about 870 ° C. As a result, the generation of nitrogen oxides is suppressed, and further, the use of limestone as the fluid medium has the advantage that in-furnace desulfurization is simultaneously performed.

  As a fuel for the pressurized fluidized bed boiler, a coal / water paste (CWP: Coal Water Paste, hereinafter sometimes referred to as CWP) made of a mixture of coal, limestone, and water is used. CWP is produced by kneading a pulverized coal slurry made of a mixture of pulverized coal and water, coarse pulverized coal having a particle diameter of 2 mm or less, limestone, and water for viscosity adjustment with a kneader. Although the properties of CWP vary depending on the coal type, the viscosity of standard CWP is 4 to 10 Pa · s, and the water content is about 24 to 25% by weight. The coal concentration of the pulverized coal slurry is about 50% by weight, and is produced by pulverizing with a pulverizer while adding water to coarse pulverized coal having a particle size of 2 mm or less. CWP easily separates coal and water if the viscosity is low, and conversely if the viscosity is too high, it will be easily blocked in the piping, so the CWP viscosity at the kneader outlet and the water content of the coarse coal are measured online. The amount of water injected into the kneader is adjusted using these measured values, and the viscosity of the CWP is controlled to be within the set range. The produced CWP is supplied to the furnace through a CWP pump.

  If the amount of water contained in the coarse coal increases, it will be necessary to reduce the amount of water used for viscosity adjustment supplied to the kneader, but if the amount of water contained in the coarse coal becomes extremely large, even if the water injection is completely stopped , CWP viscosity may be outside the set range. In this case, a method of adjusting the viscosity by reducing the amount of water in the CWP by reducing the amount of water in the pulverized coal slurry can be considered, but if the amount of water in the pulverized coal slurry is simply reduced, Developed a method to produce a pulverized coal slurry with low moisture content by reducing the amount of water supplied to the pulverizer and supplying surfactant to the pulverizer, assuming that the particle size of pulverized coal pulverized in (For example, refer to Patent Document 1).

Japanese Patent No. 4029230

  In order to stably operate a pressurized fluidized bed boiler using CWP as fuel, it is preferable that the properties of CWP, in particular, the viscosity is constant and the fluctuation is small. In order to increase the power generation efficiency, it is desirable that the CWP has as little water as possible within a range that can be stably transported. Even in the production of conventional CWP, the viscosity of the CWP at the kneader outlet and the moisture content of the coarse coal are measured online, and using these measured values, the controller adjusts the amount of water for viscosity adjustment to the kneader, Although the viscosity of CWP is controlled to be within the set range, the viscosity range of CWP to be manufactured is relatively wide, and if the amount of water in the pulverized coal slurry increases, the viscosity of CWP may be outside the set range. was there.

  An object of the present invention is to provide a coal / water paste production apparatus capable of producing a coal / water paste whose viscosity is controlled more uniformly than a conventional coal / water paste production apparatus.

  The present invention according to claim 1 includes a kneader for kneading pulverized coal slurry, coarse coal, limestone and water, a fine pulverizer for mixing coarse pulverized coal with water while finely pulverizing the coarse coal, and pouring water into the fine pulverizer. A pulverizer water injection device, a pulverizer coal feeder equipped with a moisture meter for measuring the moisture content of coarse pulverized coal supplied to the pulverizer online, and the viscosity of the pulverized coal slurry at the outlet of the pulverizer online Viscosity adjustment to pulverized coal slurry production apparatus equipped with pulverized coal slurry viscosity detection means to detect, a kneader coal feeder equipped with a moisture meter that measures the moisture content of coarse pulverized coal supplied to the kneader online, and the kneader A water injection device for supplying water for use, a coal / water paste viscometer that measures the viscosity of coal / water paste at the outlet of the kneader online, a viscosity measurement value of pulverized coal slurry, and a moisture content measurement of coarse coal With value Adjusting the amount of water injected into the pulverizer and controlling the viscosity of the pulverized coal slurry to be constant, and kneading using the measured viscosity value of the coal / water paste, the measured moisture content of the coarse pulverized coal, and the measured viscosity value of the pulverized coal slurry A controller for adjusting the amount of water injected into the machine and controlling the viscosity of the coal / water paste to be constant, and the kneader is supplied with pulverized coal slurry whose viscosity is controlled to be constant. This is a coal / water paste manufacturing apparatus.

  In the coal / water paste manufacturing apparatus according to claim 1, the present invention described in claim 2 further supplies the biomass to the kneader to produce the coal / water paste containing biomass. The apparatus adjusts the amount of water injected into the kneader using the measured value of the viscosity of the coal / water paste, the measured value of the water content of the coarse coal, the measured value of the moisture content of the biomass and the measured value of the viscosity of the pulverized coal slurry. The viscosity of the paste is controlled to be constant.

  According to a third aspect of the present invention, in the coal / water paste manufacturing apparatus according to the first or second aspect, the pulverized coal slurry viscosity detecting means detects a motor current of a viscometer and / or the pulverizer. It is an ammeter.

  In the coal / water paste production apparatus according to the present invention, the pulverized coal slurry production apparatus for producing the pulverized coal slurry supplies the viscosity of the pulverized coal slurry at the outlet of the pulverizer to a pulverizer, a viscosity detecting means for detecting the viscosity online. It is equipped with a moisture meter that measures the moisture content of the coarse pulverized coal online, and the controller adjusts the amount of water injected into the pulverizer using the viscosity measurement value of the pulverized coal slurry and the moisture content measurement value of the pulverized coal. Since the viscosity of the slurry is controlled to be constant and the pulverized coal slurry whose viscosity is controlled to be constant is supplied to the kneader, the water content of the pulverized coal slurry supplied to the kneader is constant. Most of the water contained in the coal / water paste is water brought in from the pulverized coal slurry. By keeping the viscosity of the pulverized coal slurry constant, the moisture fluctuation at the inlet of the kneader becomes the fluctuation in the moisture content of the coarse coal. Only, and the fluctuation of water content is greatly reduced. Since fluctuations in the amount of water injected into the kneading machine are reduced, the adjustment of the amount of water injected is facilitated, and a coal / water paste with a more controlled viscosity can be produced as compared with conventional coal / water paste production apparatuses.

  In addition, the coal / water paste production apparatus according to the present invention, when producing coal / water paste containing biomass, is controlled so that the amount of water in the pulverized coal slurry supplied to the kneader is constant. Even if the moisture content of the coarse pulverized coal varies, it is possible to produce a coal / water paste whose viscosity is controlled to be constant compared to a conventional coal / water paste production apparatus. Thereby, the operation of the pressurized fluidized bed boiler using coal / water paste whose raw material is sewage sludge having a high water content as fuel can be stably performed.

  Further, according to the present invention, the viscosity detecting means for detecting the viscosity of the pulverized coal slurry at the outlet of the pulverizer online is a viscometer and / or an ammeter that detects the motor current of the pulverizer. can do.

It is a figure which shows schematic structure of the coal and water paste manufacturing apparatus 1 of 1st Embodiment of this invention. FIG. 3 is a basic control system diagram of the amount of water injected into the pulverizer 37 of FIG. 1.

  FIG. 1 is a diagram showing a schematic configuration of a coal / water paste manufacturing apparatus 1 according to a first embodiment of the present invention. The coal / water paste production apparatus 1 is an apparatus for producing a coal / water paste (CWP) composed of pulverized coal slurry, coarse coal obtained by pulverizing raw coal to a predetermined particle size, limestone having a predetermined particle size, and water. A kneading machine 3 for kneading pulverized coal slurry, coarse pulverized coal, limestone and water, a viscometer 5 for measuring the viscosity of CWP kneaded by the kneading machine 3, a pulverized coal slurry production apparatus 7 for producing a pulverized coal slurry, A coal feeder 9 for supplying pulverized coal to the kneader 3, a kneader water injection device 11 for supplying water for viscosity adjustment to the kneader 3, a pulverizer 37, and a controller 13 for controlling the amount of water injected to the kneader 3 Including.

  The kneading machine 3 is a horizontal kneading machine, for the pulverized coal slurry produced by the pulverized coal slurry production apparatus 7, the coarse pulverized coal and limestone supplied from the coal feeder 9, and for viscosity adjustment supplied as necessary. The water is continuously received and kneaded to produce CWP. The CWP is controlled to have a viscosity value set within a range of 4 to 10 Pa · s. At this time, the water content of CWP is about 24 to 25% by weight, and the coal concentration is about 69 to 70% by weight. The manufactured CWP is sent to the CWP tank 17 through the distribution conveyor 15 and then supplied to the furnace (not shown) via a CWP pump (not shown).

  A viscometer 5 is attached to the outlet of the kneader 3, and the viscometer 5 measures the viscosity of CWP discharged from the kneader 3 online. The measured viscosity measurement value is sent to the control device 13 and used for adjusting the amount of water injected into the kneader 3. The viscometer 5 is provided at the kneader exit, and includes a CWP introduction guide plate (not shown), a viscosity measuring container (not shown), a rotating rotor (not shown), a torque meter (not shown), a CWP discharge gate, and a washing nozzle. (Not shown). Part of the CWP discharged from the kneader outlet is guided to the viscosity measuring container via the CWP introduction guide plate, the pin type rotor is rotated, and the stirring torque at this time is measured with a torque meter. Since there is a correlation between the stirring torque and the CWP viscosity, the CWP viscosity can be easily obtained by acquiring the relationship between the stirring torque and the CWP viscosity in advance. When the viscosity measurement is completed, the CWP discharge gate is opened and CWP is discharged, and water is injected into the viscosity measurement container and the like to perform cleaning. These operations are automatically performed at predetermined intervals via the control device 13.

  Coarse coal is coal having an average particle size of 2 mm or less obtained by pulverizing raw coal with a pulverizer. Coarse coal stored in the pulverized coal relay hopper 19 is supplied to the kneader 3 via the coal feeder 9. . At this time, limestone is also sent from the limestone bunker 21 to the coal feeder 9 and supplied to the kneader 3 together with the coarse coal. About 75% by weight of the coal contained in CWP is supplied as coarse coal. The raw coal normally contains about 10% by weight of water, but the moisture content varies depending on the environment of the coal yard and the weather. For this reason, the coal feeder 9 is equipped with a non-contact type moisture meter 23, whereby the moisture content of the coarse coal is measured online. The water content of the coarse coal is sent to the control device 13 and used for adjusting the viscosity of the CWP.

  After the pulverized coal slurry is manufactured by the pulverized coal slurry manufacturing apparatus 7, a predetermined amount of pulverized coal slurry is supplied to the kneader 3 through the relay tank 25, the slurry transfer pump 27, the slurry service tank 29, and the slurry supply pump 31. . The supplied pulverized coal slurry is controlled to have a viscosity value set within a range of 100 to 400 mPa · s. The water content of the pulverized coal slurry is about 48 to 50% by weight, and about 70% by weight of the water contained in the CWP is water brought from the pulverized coal slurry. Details of the pulverized coal slurry production apparatus 7 will be described later.

  Water is poured into the kneader 3 by the kneader water injection device 11. The kneading machine water injection device 11 is a device for supplying water for viscosity adjustment, and includes a water injection flow rate adjustment valve 35 in the middle of a water injection pipe provided on the discharge side of the water injection pump 33, and the control device 13 is a water injection flow rate adjustment valve. The amount of water injected into the kneader 3 is adjusted by adjusting the valve opening of 35.

  The pulverized coal slurry manufacturing apparatus 7 includes a pulverizer 37 that is a wet mill, and the pulverized coal stored in the pulverized coal relay hopper 38 is supplied to the pulverizer 37 via a coal feeder 39 for the pulverizer. In addition, viscosity adjusting water is supplied from the fine crusher water injection device 41. The pulverized coal supplied to the pulverizer 37 is the same as the pulverized coal supplied to the kneader 3. Similarly to the coal feeder 9 for the kneader, a non-contact type moisture meter 43 capable of measuring moisture online is also attached to the coal feeder 39 for the fine pulverizer. The measured water content of the coarse coal is sent to the control device 13 and used to adjust the viscosity of the pulverized coal slurry. The fine pulverizer water injection device 41 includes a water injection flow rate adjustment valve 47 in the middle of the water injection pipe provided on the discharge side of the water injection pump 45, and the control device 13 adjusts the valve opening of the water injection flow rate adjustment valve 47 to finely pulverize. The amount of water injected into the machine 37 is adjusted.

  A viscometer 49 capable of measuring the viscosity online is also mounted at the outlet of the pulverizer 37 as in the kneader 3. The viscometer 49 that measures the viscosity of the pulverized coal slurry has the same configuration as the viscometer 5 that measures the viscosity of the CWP, but the viscosity of the pulverized coal slurry is about 100 to 400 mPa · s, Since the rotating rotor (not shown) of the viscometer 49 is thicker than the rotating rotor (not shown) of the CWP viscometer 5, the resistance of the pulverized coal slurry is reduced. A rotating rotor that is easy to receive is used. The measured viscosity value is sent to the control device 13.

  For measuring the viscosity of the pulverized coal slurry, instead of the viscometer 49, the required power of the pulverizer 37 may be measured and used. As the viscosity of the pulverized coal slurry increases, the required power of the pulverizer 37 also increases. Therefore, by obtaining the relationship between the viscosity of the pulverized coal slurry and the required power of the pulverizer 37 in advance, The viscosity of the pulverized coal slurry can be calculated from the required power measurement value. Although it is less accurate than the viscometer 49, it can be implemented easily. As a method for measuring the required power of the pulverizer 37, there is a method of measuring the current of the drive motor with an ammeter (not shown).

  The control device 13 includes input / output means for inputting / outputting signals, storage means for storing measurement values inputted through the input means, and arithmetic means, so that the pulverized coal slurry viscosity at the outlet of the pulverizer becomes a set value. The amount of water injected into the fine pulverizer 37 is adjusted using the measured viscosity value at the outlet of the fine pulverizer and the measured water content of the coarse coal powder.

  FIG. 2 is a basic control system diagram of the amount of water injected into the pulverizer 37. Adjustment of the amount of water injected into the pulverizer 37 is performed in the following manner. Coarse pulverized coal supply amount 51 and pulverized coal water content measurement value 53 are input to adder 55, and this added value 57 is sent to adder 59, and the slurry viscosity measurement value at the exit of the fine pulverizer calculated by subtractor 61 is added thereto. A deviation value 67 between 63 and the slurry viscosity setting value 65 at the outlet of the fine pulverizer is added to calculate a water injection flow rate 69 to be injected. A subtractor 75 calculates a deviation 73 between the calculated water injection flow rate 69 and the actual water injection flow rate 71, and the control device 13 controls the water injection flow rate adjustment valve 47 based on this.

  Further, the control device 13 uses the CWP viscosity measurement value at the kneader outlet, the moisture content measurement value of the coarse coal, and the viscosity measurement value of the pulverized coal slurry so that the CWP viscosity at the kneader exit becomes a set value. Adjust the amount of water injected into the. The procedure for adjusting the amount of water injected into the kneader 3 is basically the same as the procedure for adjusting the amount of water injected into the pulverized coal slurry, but in addition to the measured water content of the coarse pulverized coal, the viscosity measured value of the pulverized coal slurry is The amount of water used is calculated. Since there is a correlation between the viscosity of the pulverized coal slurry and the moisture content of the pulverized coal slurry, by obtaining the relationship between the viscosity of the pulverized coal slurry and the moisture content of the pulverized coal slurry in advance, The water content of the pulverized coal slurry can be calculated from the measured viscosity value.

  In a pressurized fluidized bed boiler, in addition to coal, mixed combustion may be performed in which biomass containing organic sludge such as sewage sludge is burned together with coal. In this case, biomass is directly supplied to the kneader 3 together with coarse coal, etc., and CWP using the biomass as part of the fuel is produced. When producing CWP using biomass as a part of fuel, a moisture content measurement value contained in the biomass is input to the control device 13, and this moisture content measurement value is handled in the same manner as the moisture content of the coarse coal. Adjust the amount of water injection to 3.

  Since about 70% by weight of the water contained in CWP is brought from the pulverized coal slurry, the influence of fluctuations in the viscosity of the pulverized coal slurry on the viscosity control of CWP is great. For example, when the water content of coarse coal supplied to the kneading machine 3 in standard CWP decreases by 1% by weight, the amount of water supplied to the kneading machine 3 is increased by about 1.3 times in order to keep the CWP viscosity constant. There is a need. On the other hand, when the water content of the pulverized coal slurry is reduced by 1% by weight, it is necessary to increase the water injection amount by about 1.5 times. Thus, the fluctuation of the water content of the pulverized coal slurry has a greater effect on the adjustment of the amount of water injected into the kneader 3 than the fluctuation of the water content of the coarse pulverized coal. In addition, when both the moisture content of coarse pulverized coal and the moisture content of the pulverized coal slurry are reduced by 1% by weight, it is necessary to increase the water injection amount by about 1.9 times.

  As described above, the coal / water paste production apparatus 1 shown in the present embodiment produces a pulverized coal slurry in which the viscosity is controlled to a constant value, which is not found in the conventional coal / water paste production apparatus, and this is mixed with the kneader 3. Since the method of supplying to the kneading machine is adopted, the moisture fluctuation on the inlet side of the kneader is only the fluctuation of the moisture content of the coarse coal, and the fluctuation of the moisture content is greatly reduced. Since the fluctuation of the water injection amount to the kneading machine 3 becomes small, it becomes possible to control the water injection amount easily and accurately, the fluctuation range of the viscosity of the coal / water paste is very small, and the conventional coal / water paste production apparatus Compared to the above, it is possible to produce a coal / water paste whose viscosity is controlled more uniformly. Thereby, the operation | movement of the stable pressurized fluidized bed boiler is attained, and the piping blockage at the time of coal and water paste transportation can be prevented reliably.

  In particular, when producing coal / water paste containing biomass having a high water content such as sewage sludge, the amount of moisture brought into the kneading machine 3 is increased, and the adjustment range of the amount of water injected into the kneading machine 3 is reduced, making control difficult. However, in the coal / water paste production apparatus 1 shown in the present embodiment, the amount of water in the pulverized coal slurry is constant, so when producing a coal / water paste containing biomass having a high water content such as sewage sludge. A coal / water paste with a constant viscosity can be produced.

DESCRIPTION OF SYMBOLS 1 Coal / water paste manufacturing apparatus 3 Kneading machine 5 Viscometer 7 Pulverized coal slurry manufacturing apparatus 9 Coal feeder 11 Kneading machine water injection device 13 Control device 23 Moisture meter 35 Water injection flow rate adjusting valve 37 Fine grinding machine 39 Coal feeding machine 41 Fine grinding Machine water injection device 43 Moisture meter 47 Water injection flow rate adjustment valve 49 Viscometer

Claims (3)

A kneader for kneading pulverized coal slurry, coarse coal, limestone and water;
A fine pulverizer for mixing coarse pulverized coal with water while finely pulverizing, a fine pulverizer injection device for injecting water into the fine pulverizer, and a moisture meter for measuring the moisture content of the coarse pulverized coal supplied to the fine pulverizer online. A pulverized coal slurry feeder equipped with a pulverized coal slurry, and a pulverized coal slurry viscosity detecting means for detecting the viscosity of the pulverized coal slurry at the outlet of the pulverizer online;
A kneading machine coal feeder equipped with a moisture meter that measures the moisture content of the coarse coal supplied to the kneading machine online;
A kneader water injection device for supplying water for viscosity adjustment to the kneader;
A coal / water paste viscometer that measures the viscosity of the coal / water paste at the outlet of the kneader online;
Adjusting the amount of water injected into the pulverizer using the measured value of the viscosity of the pulverized coal slurry and the measured value of the moisture content of the coarse pulverized coal, and controlling the viscosity of the pulverized coal slurry to be constant, the measured value of the viscosity of the coal / water paste, A control device that adjusts the amount of water injected into the kneader using the measured water content of the coarse coal and the measured viscosity of the pulverized coal slurry, and controls the viscosity of the coal / water paste to be constant,
A pulverized coal slurry whose viscosity is controlled to be constant is supplied to the kneader.   Further, when the biomass is supplied to the kneader and the coal / water paste containing biomass is produced, the control device is configured to measure the viscosity of the coal / water paste, the moisture content of the coarse coal, and the moisture content of the biomass. 2. The coal / water paste production according to claim 1, wherein the measured value and the viscosity measurement value of the pulverized coal slurry are used to adjust the amount of water injected into the kneader and to control the viscosity of the coal / water paste to be constant. apparatus.   The coal / water paste manufacturing apparatus according to claim 1 or 2, wherein the pulverized coal slurry viscosity detecting means is a viscometer and / or an ammeter that detects a motor current of the pulverizer.

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