JPS61283691A - Production of high-concentration coal-water slurry in short time - Google Patents

Abstract

PURPOSE:To obtain the title slurry in a short time using a simple device, by consolidating a specific mixture comprising a pulverized coal, water and a dispersant and applying a shear force to the consolidated mixture in a saturated state of water, to thereby liquefy the mixture. CONSTITUTION:A coal 1 is pulverized with a vertical roller mill 2 etc. while blowing a heated air which has been produced in an air heater 4 into the mill. The pulverized coal 3 is transferred to a mixing step 6 where the pulverized coal is mixed with water 7 of which the pH value has been adjusted, a dispersant 9 comprising a surfactant and optionally a stabilizer 13 such as CMC so as to have a coal content of 60wt% or higher, and the pulverized coal which is in a sufficiently dispersed state and water are formed into a mixture 10 which is in a packing state of a funicular region. A pressure is applied to the mixture from the outside to consolidate the mixture 11. When the degree of saturation of water approaches saturation point, a shearing force is applied to the end of the consolidation product to instantaneously liquefy the consolidation product, thereby obtaining the title slurry 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high-speed method for producing highly concentrated coal-water slurry. Specifically, it is a method for producing high-concentration coal-water slurry at high speed using a dry method.

[Conventional technology]

High-concentration coal-water slurry can be used not only for transportation and storage but also for direct combustion by fluidizing coal, which is a solid fuel. Furthermore, it is an effective fuel because it can reduce ash and sulfur content.

Methods for producing high-concentration coal-water slurry include wet methods and dry methods.

In the case of the wet method, wet pulverization is performed using a ball mill or the like by supplying crushed coal, a dispersant consisting of water and a surfactant, and a highly concentrated coal-water slurry with a coal concentration of about 60% by weight or more is produced. Manufacture.

At this time, a stabilizer is additionally added as required.

In the case of the dry method, conventionally a vertical roller mill etc. was used.
Crushed coal was pulverized into pulverized coal, and a highly concentrated coal-water slurry with a coal concentration of about 60% by weight or more was produced by stirring and mixing the pulverized coal with a dispersant consisting of water and a surfactant. . Continuous mixing equipment is usually used for the stirring and mixing operation, but in order to sufficiently mix the pulverized coal and water and form a slurry, a batch-type multi-stage operation that repeats stirring and mixing is performed, which is relatively slow. It required long operation time.

(e.g., E. Knell et al., MODERN p.
OWEFLSYSTEMS, September 1
984. (See pp. 63-65) Note that the pH of the water is appropriately adjusted using a pH adjuster.

Further, as in the case of the wet method, a stabilizer may be additionally added as necessary.

[Problem to be solved by the invention 3 The conventional method described above requires a long operation time to stir and mix the pulverized coal and water, and also causes agglomeration phenomenon and energy consumption in the stirring and mixing process. Not only does this cause an increase in the movement speed of the mixture, but also the interaction between the pulverized coal, water, and dispersant during stirring and mixing is limited to the interaction with the interface of the pulverized coal that has already been pulverized. As a result, the affinity between the new interface created by the pulverization of coal particles and the dispersant and pH adjuster is not sufficient, and the effectiveness of the dispersant and other chemicals when producing a low-viscosity, high-concentration coal-water slurry is reduced. There was a problem that it could not be effective.

[Means for solving problems]

In order to rapidly produce a highly concentrated coal-water slurry with low viscosity and good fluidity, the present invention has developed a cord-like region consisting of pulverized coal, water, and a dispersant, with a stabilizer added as necessary. It is characterized by compacting the filling mixture and liquefying it by shearing force under substantially water-saturated conditions.

[For production]

In the present invention, a mixture is first made of pulverized coal, water, and a dispersant, and a stabilizer is added as necessary to form a mixture that fills the cord-like region.

The filling structure of pulverized coal is either a continuous filling of pulverized coal particles, water, and air, or a cord-like region filled with only air discontinuously. . When pressure is applied to the mixture in this filling structure to compact it, its volume decreases and air is released. In this way, the water saturation increases and approaches 100%, and when the water saturation is reached, a shear force is applied to the end of the consolidation layer to instantaneously liquefy it and obtain a highly concentrated coal-water slurry. It is something.

At this time, the pulverized coal is subjected to frictional force and becomes finer, and a new interface of the pulverized coal is generated, and water, dispersant, etc.
The affinity with the stabilizer is promoted. Furthermore, due to the frictional force, a temperature rise is observed at the fracture surface, and the viscosity of the highly concentrated coal-water slurry is reduced.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a process diagram showing one embodiment of the present invention.

Coal 1 is pulverized by a vertical roller mill 2 or the like to obtain pulverized coal 3. The air heater 4 generates heated air 5 necessary for pulverization. In the mixing step 6,
Pulverized coal 3. PH-adjusted water 7 and dispersant 9 are respectively supplied and mixed so that the coal ratio of mixture 10 is 60% by weight or more.

The dispersant 9 is made of a surfactant and acts by adsorbing on the surface of the pulverized coal, and with sufficient potential energy, it maintains a filling state of sufficiently dispersed pulverized coal particles and water without forming aggregates among the pulverized coal. used to obtain The above-mentioned filling structure exists as a funicular region.

In addition, stabilizers 13 are blended as needed, but natural polysaccharides such as xanthone gum and CMC (sodium
Carboxymethyl (1: ellulos
a) etc. are used to form weak aggregates in a highly concentrated coal-water slurry through the interaction of polymer chains, thereby stabilizing the properties.

Further, the mixture 10 is consolidated in a consolidation liquefaction step 11 by applying pressure from the outside to the mixture 10, and when the degree of water saturation reaches a saturated state, the end of the consolidated body is formed under water gushing out. By applying a shearing force to the portion, liquefaction is instantaneously performed, and a high concentration coal water slurry 12 can be obtained.

The analysis results of the coal used in the examples were as follows.

HGI50(-) Also, particle size analysis of pulverized coal (by Microtrack method)
The results were as follows.

106 95゜1 7580゜2 53 70.1 38 51.3 27 38.4 19 29.0 13 17.8 9.4 13.2 6・68.2 4.7 6.0 3.3 4.3 2.4 3.0 The formulation consists of 70% by weight of pulverized coal, Ca(OH), and pH
358 kg of a mixture consisting of wet pulverized coal obtained by stirring and mixing with a ratio of 29.4% by weight of water adjusted to 9.0% by weight and 0.06% by weight of a dispersant made of an anionic surfactant.
Consolidation was performed under a compressive force of /aJ to form a consolidated layer with a bulk density (wet basis) of 1.01 g/aJ, and the free surface at the end of the consolidated layer was further rotated at an average circumferential speed of 5 m/s. A high concentration coal-water slurry having sufficient fluidity without reducing the viscosity to 750 CP was obtained by applying shearing force using a disk.

At this time, the axial velocity of the compacted layer is about 0.5 am/Sec, and the surface temperature of the compacted layer is about 47° C., promoting high-speed shearing action under these processes.

The particle size distribution of the coal particles in the high-concentration coal-water slurry was as shown below, and was finer than that of pulverized coal.

Particle size μm Under sieve Percentage% 150
99.8 106 95.2 75 82.3 53 72.3 38 56.0 27 45.9 19 33.4 13 24.0 9.4 18.2 6.6 12.0 4.7 8.2 3 .3 6, 3 2.4 4.3 [Effects of the Invention] According to the present invention, *by compacting the mixture that fills the cord-like region, mainly consisting of powdered coal and water, and liquefying it by shearing force. , the refinement of pulverized coal particles and the increase in the surface temperature of the consolidated layer were observed, as well as water and dispersant.

By promoting affinity with stabilizers, etc., it is possible to rapidly produce a highly concentrated coal-water slurry with a coal concentration of about 60% by weight or more, which has low viscosity and good fluidity, and is much easier to use than conventional methods. Since the operating time can be shortened in comparison, the device can be significantly simplified.

[Brief explanation of drawings]

FIG. 1 is a process diagram according to an embodiment of the present invention. 3...Pulverized coal 7...Water 9...Dispersant 10...Mixture 12...Highly concentrated coal-water slurry procedure amendment (wall 2) 1. Display of case 3, Amendment person case and Relationship between patent applicant representative Hiroshi Haseyo

Claims (1)

[Claims] A mixture consisting of pulverized coal, water, and a dispersant, with a stabilizer added if necessary, that fills the cord-like region is compacted, and this is liquefied by shearing force under nearly water-saturated conditions. A high-speed production method for highly concentrated coal-water slurry.