JP4770147B2 - Coal dry grinding aid and dry grinding method - Google Patents

Description

  The present invention relates to a dry pulverization aid for coal and a dry pulverization method for coal using the dry pulverization aid, and in particular, greatly improves coal pulverization efficiency with a smaller amount of addition than conventional dry pulverization aids. The present invention relates to a dry pulverization aid for coal and a method for efficiently dry pulverizing coal using the dry pulverization aid.

  In a coal-fired power plant adopting pulverized coal combustion, coal as a fuel raw material is dry pulverized by a pulverizer such as a tube mill or a vertical mill, and then classified and burned as pulverized fuel. In consideration of the combustion efficiency of the pulverized fuel, the treatment of ash after combustion, etc., it is required to obtain pulverized coal having a low particle size by more advanced pulverization and to increase the combustion efficiency. In steelworks with coke ovens, repulsive crushers, hammer crushers, etc. are used as pretreatment equipment for charged coal. Even in these equipment, coal particles with a particle size of 3 mm or less are efficiently produced by grinding. Need to get.

  Conventionally, various grinding aids for increasing grinding efficiency have been proposed. For example, in the field of cement production, grinding aids such as triethanolamine are used for fine grinding of clinker. Japanese Patent Publication No. Sho 54-13629 proposes the addition of graphite as a grinding aid for metals and powders.

As a dry pulverization aid for coal, Japanese Patent Application Laid-Open No. 1-127057 discloses a dry pulverization aid for coal containing carbon black. A dry grinding aid has been proposed.
Japanese Patent Publication No.54-13629 Japanese Patent Laid-Open No. 1-127057 Japanese Unexamined Patent Publication No. 1-127058

  However, none of the conventional grinding aids can exhibit a sufficient grinding efficiency improvement effect. That is, all of the conventional grinding aids are insufficient in the dispersion effect of the fine powder produced by grinding, and the fine powder aggregates in the grinding system, so that the force applied to the coal from the grinding machine is dispersed. Therefore, as a result, a sufficient effect of improving the pulverization efficiency could not be obtained. Moreover, the conventional grinding | pulverization adjuvant had the problem that the required addition amount with respect to coal is comparatively much as about 0.5 weight%, and auxiliary | assistant cost is expensive.

  The present invention solves the above-mentioned conventional problems, and a dry pulverization aid for coal, which can significantly improve the pulverization efficiency of coal with a smaller amount of addition than the conventional dry pulverization aid, and such dry pulverization An object is to provide a method for efficiently dry-pulverizing coal using an auxiliary agent.

The coal dry grinding aid of the present invention (Claim 1) is characterized by comprising a dialkylsulfosuccinic acid and / or a salt thereof.

  The coal dry pulverization aid according to claim 2 is the same as in claim 1, wherein the alkyl group of the dialkylsulfosuccinic acid has 8 to 16 carbon atoms, and the dialkylsulfosuccinate is a sodium salt, potassium salt and ammonium salt. It is one type or two or more types selected.

The dry pulverization method for coal according to the present invention (Claim 3 ) is characterized in that dry pulverization is performed by adding the coal dry pulverization aid according to claim 1 or 2 to the coal.

The dry pulverization method for coal according to claim 4 is characterized in that, in claim 3 , the dry pulverization aid for coal according to claim 3 is sprayed onto the coal on the belt conveyor before the pulverizer.

The dry pulverization method of coal according to claim 5 is the dry pulverization of coal according to claim 3 or 4 , so that the amount of dialkylsulfosuccinic acid and / or its salt added to the coal is 0.01 to 0.1% by weight. An auxiliary agent is added.

Dialkylsulfosuccinic acid and / or its salt (hereinafter sometimes referred to as “dialkylsulfosuccinic acid (salt)”) has the following effects and greatly improves the dry grinding efficiency of coal with a small addition amount. Can be improved.
(1) Providing coal with fluidity and promoting the supply of coal from the non-pulverized area to the pulverized area where no pulverization occurs in the pulverizer
(2) By increasing the dispersibility of the coal fine powder produced by pulverization and preventing the fine powder from agglomerating, the force applied to the coal from the pulverizer is reliably applied without being dispersed.

  According to the dry pulverization aid and dry pulverization method of coal of the present invention using such a dialkylsulfosuccinic acid (salt), the pulverization efficiency of coal can be greatly improved with a small amount of auxiliary agent added, and the cost is low. Efficient grinding process. According to the present invention, it is possible to easily obtain pulverized coal suitable for pulverized fuel with good productivity and economy without making a large-scale change to a coal pulverizer. .

  As the dialkylsulfosuccinic acid, those having an alkyl group having 8 to 16 carbon atoms are preferable, and as the dialkylsulfosuccinate, sodium salt, potassium salt and ammonium salt are preferable.

  The dialkylsulfosuccinic acid (salt) is preferably used as a solution of water, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, glycerin, and the like. ) The solution is preferably sprayed onto the coal on the belt conveyor before the pulverizer, and the amount of dialkylsulfosuccinic acid (salt) added to the coal is preferably 0.01 to 0.1% by weight.

  Embodiments of the coal dry grinding aid and the dry grinding method of the present invention will be described in detail below.

（式中、Ｒは直鎖又は分岐のアルキル基、Ｍは水素、又はアルカリ金属元素等の塩形成元素（群）） In the present invention, a dialkylsulfosuccinic acid (salt) used as an active ingredient of a dry grinding aid is represented by the following general formula.

(Wherein R is a linear or branched alkyl group, M is hydrogen or a salt-forming element (group) such as an alkali metal element)

  The number of carbon atoms of the alkyl group of the dialkylsulfosuccinic acid (salt) used in the present invention is preferably about 6 to 16 in terms of its effects of fluidity imparting effect, fine powder dispersing effect and the like. Examples of the group include octyl group, 2-ethylhexyl group, nonyl group, decyl group, dodecyl group and the like. Examples of the dialkylsulfosuccinate include alkali metal salts and ammonium salts of dialkylsulfosuccinate such as sodium and potassium. These dialkylsulfosuccinic acids (salts) may be used alone or in a combination of two or more.

  In the present invention, such a dialkylsulfosuccinic acid (salt) is added to coal, and then, according to a conventional method, the coal is dry-pulverized by a pulverizer such as a tube mill or a vertical mill.

  At this time, the dialkylsulfosuccinic acid (salt) is preferably used as a solution in order to uniformly add to coal. In this case, the solvent used may be water, but in particular, ethylene glycol, propylene glycol, diethylene glycol. It is preferable to use glycols or glycol ethers such as triethylene glycol, dipropylene glycol, tripropylene glycol, glycerin and the like from the viewpoint of improving the grinding efficiency. In addition, when setting it as a solution, 1 type of these solvents may be used independently, and 2 or more types may be mixed and used.

  The dialkylsulfosuccinic acid (salt) concentration of the dialkylsulfosuccinic acid (salt) solution is appropriately determined according to the type of dialkylsulfosuccinic acid (salt) to be used so as to be a low viscosity solution suitable for uniform addition to coal.

  The amount of dialkylsulfosuccinic acid (salt) added to coal is preferably 0.01% by weight or more, and particularly preferably 0.01 to 0.1% by weight. If the amount added is too small, a sufficient effect of improving the pulverization efficiency cannot be obtained, and if it is too large, it is economically disadvantageous.

  There is no particular limitation on the method of adding dialkylsulfosuccinic acid (salt) to coal, but in order to add dialkylsulfosuccinic acid (salt) uniformly to coal before pulverization without using special equipment, for example, A method of spraying a dialkylsulfosuccinic acid (salt) solution using a spray nozzle on coal on a belt conveyor that transports coal to a pulverizer is preferable.

  If it is this method, it can add uniformly in the state which raised the contact efficiency of coal and a dialkyl sulfosuccinic acid (salt) only by installing a spray nozzle on the belt conveyor for coal conveyance. However, the addition method and the addition location of dialkylsulfosuccinic acid (salt) to coal are not limited to the above methods as long as they can be uniformly added to coal before pulverization. For example, dialkylsulfosuccinic acid (salt) may be added to and mixed with coal in advance and then charged into a pulverizer, or dialkylsulfosuccinic acid (salt) may be added during pulverization.

  In the present invention, carbon black, higher fatty acids or salts thereof, which are conventional grinding aids, can be used in combination with dialkylsulfosuccinic acid (salt).

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

Example 1, Comparative Examples 1-8
The auxiliary agent shown in Table 1 was added to the dry coal classified to 0.59 to 1.19 mm in the addition amount shown in Table 1 and mixed well (however, in Comparative Example 1, no auxiliary agent was added). . 10.0 g of the obtained mixture was put in a hard glove testing machine and ground for 10 minutes. After pulverization, the pulverized pulverized coal was taken out, the ratio of the 200 mesh sieve passing portion was examined, and the results are shown in Table 1.

  From Table 1, it is clear that the pulverization aid of the present invention can obtain excellent pulverization results with an addition amount of 1/10 compared with conventional auxiliaries, and is remarkably excellent in the improvement effect of pulverization efficiency. It is.

Claims (5)

A coal dry grinding aid comprising a dialkylsulfosuccinic acid and / or a salt thereof.   In Claim 1, Carbon number of the alkyl group of dialkyl sulfosuccinic acid is 8-16, Dialkyl sulfosuccinate is 1 type, or 2 or more types chosen from the group which consists of a sodium salt, potassium salt, and ammonium salt. Characteristic coal dry grinding aid. Coal, dry milling method of coal characterized by dry grinding with addition of dry grinding aid coal according to claim 1 or 2. According to claim 3, dry milling method of coal characterized by spraying the dry grinding aid of coal according to claim 3 in the coal on the grinding machine before the belt conveyor. The coal according to claim 3 or 4 , wherein the coal dry pulverization aid is added so that the amount of dialkylsulfosuccinic acid and / or salt thereof added to the coal is 0.01 to 0.1 wt%. Dry grinding method.