JPH10101331A - High reactivity slaked lime and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily obtain high reactivity slaked lime having high reactivity with acidic gas in the conventional facilities by adding alcohols, amines or saccharides to powdery quick lime and bringing them into slaking reaction with water. SOLUTION: One or more kinds of alcohols, amines or saccharides are added to quick lime by 0.02-50wt.%, preferably 0.5-25wt.% of the amt. of the quick lime, they are mixed or the quick lime is coated with the additives and slaking water is added to produce the objective high reactivity slaked lime having a large specific surface area. In other way, the additives are dissolved in water to produce slaking water and quick lime is slaked with the slaking water. Water-soluble glycol and glycerol are preferably used as the alcohols. Water-soluble prim. to tert. amines are used as the amines. Sucrose and glucose are used as the saccharides.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for industrially removing slaked lime with enhanced reactivity and slaked lime with enhanced reactivity in order to efficiently remove acid gases and the like in the treatment of combustion gas and the like in a refuse incinerator. And a method for producing the same advantageously.

[0002]

2. Description of the Related Art Slaked lime production methods are broadly classified into wet digestion and dry digestion. In order to obtain slaked lime as a powder in industry, a dry digestion method is generally used.

In order to carry out the dry digestion method industrially, quick lime obtained by crushing and pulverizing the top size to about 5 mm or less is supplied to a reactor called a digester equipped with a water supply device by a raw material supply device, and the water is added to the water. Stir to allow digestion reaction. At this time, the powdered and granular quicklime reacts with water and becomes slaked lime, and the grains collapse. The slaked lime that has finished the digestion reaction is in a state in which grains and powder are mixed, and is supplied to a classifier through an aging machine.
Fine powder is divided into coarse powder and fine powder.

In this production method, the amount of water to be added is 32 to 70% by weight based on quicklime as a raw material. The water added at this time is consumed in the reaction with quick lime, and the excess water evaporates due to the heat generated during the digestion reaction, and an appropriate amount of water remains in the product.

The slaked lime obtained by such a conventional method is described in J.
It is slaked lime special number or 1 specified in ISZ9001, and its Blaine value by the air permeation method is 10,
000-20,000 square centimeters / gram, and BET specific surface area by nitrogen adsorption method is 10-20 square meters / gram.

It is said that the specific surface area should be increased in order to increase the reactivity with the acidic gas. In order to increase the specific surface area by the conventional manufacturing method, it is conceivable to classify the particles by setting the classification point to a small particle diameter, but this method reduces the product yield and increases the specific surface area. .

[0007] It is known that slaked lime having a high specific surface area can be obtained by mixing ethanol and methanol with digested water to digest quicklime.
Proposes to obtain a slaked lime with a high specific surface area by mixing quicklime strongly and uniformly with a slaked liquid composed of water and an organic solvent that delays the reaction. Organic solvents at this time are alcohols such as methanol, ethanol, propanol and butanol, as well as ketones, ethers and aldehydes. However, in this method, the organic solvent is used in a state of being mixed with water, and the amount thereof is required to be 50 to 70 parts by volume in the digested water. In the digestion process, special equipment such as a heating device, a degassing device, and a plurality of reaction vessels is required.

In Japanese Patent Laid-Open Publication No. 5-193997, methanol and / or ethanol are mixed with water so that the alcohol concentration becomes 5 to 60% by volume, and further reacted with quicklime with a surfactant added. Has been proposed. In this case, too, a large amount of alcohol is required for quicklime, and special equipment such as an alcohol recovery tower is required.

[0009]

SUMMARY OF THE INVENTION In order to obtain slaked lime having high reactivity with acid gas, that is, slaked lime having a high specific surface area, the present inventors require special equipment such as a heating device and an alcohol recovery tower in a conventional method. It is an object of the present invention to industrially and advantageously use conventional digestion equipment without requiring special equipment such as a heating device and an alcohol recovery tower.

[0010]

Means for Solving the Problems The inventors have conducted intensive studies to solve the above problems, and as a result, have found that alcohols,
It has been found that slaked lime having a large specific surface area can be obtained when a quick lime is digested and reacted in the presence of amines and saccharides, and that slaked lime can be efficiently obtained by pulverizing raw lime. Based on this finding,
The present invention has been completed.

First, divalent and trivalent water-soluble alcohols such as glycols and glycerins, and water-soluble amines such as primary amines, secondary amines and tertiary amines Or one or more additives selected from water-soluble sugars such as sucrose, glucose, fructose, etc., in an amount of 0.01 to 50% by weight, preferably 0.5 to 25% by weight with respect to quicklime. % And dissolve and disperse in digestion water. Slaked lime having a large specific surface area can be obtained by causing quicklime to undergo a digestion reaction using this digestion water. When digestion is performed by this method, conventional slaked lime production equipment may be used, and special equipment such as a heating device and an alcohol recovery tower is not required.

[0012] Among these additives, those in liquid form are not only dispersed and dissolved in digestive juices, but also added and mixed and / or coated with powdered lime before digestion, and digestion reaction is performed by adding digestive water. You may.

In adding and mixing and / or coating the additive to the powdered lime, the additive may be added to the pulverized lime and mixed and stirred by a mixer or the like.
When crushing quicklime, a special device is not required if the additive is dropped on the quicklime at the quicklime supply port of the crusher and crushed. Further, in this method, the amount of the additive to quicklime is constant, and slaked lime having a large specific surface area can be obtained stably.

Water-soluble divalent and trivalent alcohols such as glycols and glycerins, amines which are water-soluble in primary amines, secondary amines and tertiary amines; Alternatively, one or more selected from water-soluble saccharides such as sucrose, glucose, fructose, in an amount of 0.02 to 50% by weight, preferably 0.5 to 25% by weight based on quicklime. When added, the effect of increasing the specific surface area is observed. This addition rate is characterized in that the effect of increasing the specific surface area is exhibited even with a small addition rate as compared with the conventional chemical addition rate.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is implemented as follows. In Claims 1 and 3 of the claims, dihydric and trivalent water-soluble alcohols such as glycols and glycerins, primary amines,
Water-soluble amines such as secondary amines and tertiary amines, or one or more selected from water-soluble sugars such as sucrose, glucose, fructose, etc. It is dissolved and dispersed in digested water so as to be 0.02 to 50% by weight, preferably 0.5 to 25% by weight. The ratio of digested water to quicklime should be investigated in advance. Digestion water in which alcohols and the like are dissolved and dispersed is added to quicklime with stirring in a digester, and a digestion reaction is performed to produce slaked lime. The generated slaked lime is supplied to a classifier through an aging machine in a conventional process, and coarse powder is removed to be a product.

However, in this method, during continuous production, the amount of digested water added may vary depending on the degree of calcination of quicklime. In that case, the ratio of the additive to quick lime changes, and the specific surface area of slaked lime to be a product or the yield thereof may fluctuate. In such a case, claim 1 and claim 2 of [claims]
It is good to use the method shown in FIG.

In claims 1 and 2 of the claims, the additive is added to the powdered lime in advance and mixed and / or coated to stabilize the ratio of the additive to quick lime. Things. In this method, first, water-soluble divalent and trivalent alcohols such as glycols and glycerins, primary amines, secondary amines and tertiary amines are used. One or more selected from amines are added to powdered lime in an amount of 0.02 to 50% by weight, preferably 0.5 to 25% by weight, based on quicklime, and mixed and / or coated. Powdered lime to which additives are mixed and / or coated is added to digestive water and digestion reaction is performed while stirring and mixing in a digester with conventional equipment to produce slaked lime. The generated slaked lime is supplied to a classifier through an aging machine in a conventional process, and coarse powder is removed to be a product.

In this method, even if the state of quick lime fluctuates due to continuous operation for a long time and the amount of digested water is adjusted, the ratio of the additive to quick lime is fixed in advance and fluctuates by adjusting the amount of water. And a stable specific surface area and yield can be obtained.

[0019]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 5% by weight of diethylene glycol is added to powdered lime and mixed well. To 105 parts of powdered lime to which diethylene glycol was added, 58% by weight of digestion water was added with stirring to perform digestion and ripening.

The obtained slaked lime was measured for a Blaine specific surface area by an air permeation method and a BET specific surface area by a nitrogen adsorption method. The slaked lime sample reacts with the hydrogen chloride gas in the combustion gas. The slaked lime sample after the reaction was dissolved in water, and the Ca ²⁺ concentration was measured by an ion meter and the Cl ⁻ concentration was measured by ion chromatography to determine the reaction rate of slaked lime with hydrogen chloride gas.

As a result, as shown in Table 1, the specific surface area of the brane was 40,900 square centimeters / gram, and the BET
The specific surface area was 32.4 square meters / gram, and the conversion with hydrogen chloride gas was 28%.

Example 2 A solution prepared by dissolving and dispersing 5% by weight of triethanolamine with respect to quick lime in water of 58% by weight with respect to quick lime was added to 100 parts of powdered quick lime with stirring to digest it.
Aging was performed. The Blaine specific surface area, BET specific surface area, and the reaction rate with hydrogen chloride gas were determined. As a result, Table 1
As shown in the figure, the specific surface area was 46,100 square centimeters / gram, and the BET specific surface area was 39.9 square meters / gram. The conversion with hydrogen chloride gas was 23%.

Example 3 A solution prepared by dissolving and dispersing 4% by weight of sucrose in water of 50% by weight of quicklime in a water of 50% by weight of quicklime was used as a digestive solution to prepare quicklime 1
The mixture was added to 00 parts with stirring, digested and aged, and then classified to obtain fine powder slaked lime. Its brain specific surface area, BE
The T specific surface area and the reaction rate with hydrogen chloride gas were determined. As a result, as shown in Table 1, the Blaine specific surface area was 56,900.
Square centimeter / gram, BET specific surface area 22.9
Square meter / gram, reaction rate with hydrogen chloride gas 36%
Met.

Comparative Example 1 To 100 parts of quicklime, 52% by weight of water was added with stirring, digested and aged, and classified to obtain fine powdered slaked lime. The Blaine specific surface area, BET specific surface area, and the reaction rate with hydrogen chloride gas were determined. As a result, as shown in Table 1, the Blaine specific surface area was 22,300 square centimeters / gram, the BET specific surface area was 12.1 square meters / gram, and the reaction rate with hydrogen chloride gas was 6%.

[0026]

[Table 1]

[0027]

As described in detail above, according to the method for producing slaked lime of the present invention, slaked lime having a large specific surface area and a high reactivity with hydrogen chloride gas can be produced as compared with the conventional method. . According to the slaked lime obtained in the present invention, it is possible to efficiently remove hydrogen chloride gas and the like in the treatment of combustion gas and the like in a garbage incinerator, and to use less slaked lime than conventional slaked lime. Becomes possible.
As a result, the amount of generated dust can be reduced, and the life of the waste treatment plant can be extended.

Further, the method of the present invention does not require special equipment such as a heating device and an alcohol recovery tower, and can be carried out with conventional digestion equipment only by adding equipment for supplying additives. It can be carried out industrially easily and efficiently.

According to the method for producing slaked lime of the first and second aspects, slaked lime having a high specific surface area can be obtained more stably and efficiently.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Katsuhiko Amano, Inventor 1780 Nagaoka, Yamato-cho, Sakata-gun, Shiga Prefecture Omi Mining Co., Ltd. (72) Matsuzo Matsuda 1780, Nagaoka, Yamato-cho, Sakata-gun, Shiga Prefecture Omi Mining Co., Ltd. (72) Inventor Koichi Miyayama 1780 Nagaoka, Yamato-cho, Sakata-gun, Shiga Prefecture Omi Mining Co., Ltd. (72) Inventor Tokufumi Ogura 1780, Nagaoka, Yamato-cho, Sakata-gun, Shiga Prefecture Omi Mining Co., Ltd. (72) Inventor Katsuhiko Hoshiyama 1780 Nagaoka, Yamato-cho, Sakata-gun, Japan Omi Mining Co., Ltd.

Claims (7)

[Applicant Reference Number] OA107 [Claims] 1. Highly reactive slaked lime comprising slaked lime and one or more additives selected from alcohols, amines and saccharides. 2. Powdered lime is added with one or two or more of alcohols and amines in an amount of 0.02 to lime.
The method for producing highly reactive slaked lime according to claim 1, wherein digestion reaction is performed by adding digestion water in a mixed and / or coated state of 50% by weight, preferably 0.5 to 25% by weight. 3. The quicklime contains one or more of alcohols, amines and sugars in an amount of 0.02 to quicklime.
The method for producing highly reactive slaked lime according to claim 1, characterized in that water having dissolved therein 50 to 50% by weight, preferably 0.5 to 25% by weight, is added as digestion water to cause a digestion reaction. 4. The highly reactive lime according to claim 1, wherein when crushing quick lime, quick lime is coated by adding one or more of alcohols and amines. A method for producing slaked lime. 5. The method for producing highly reactive slaked lime according to claim 1, wherein the alcohol is a bivalent and trivalent water-soluble alcohol such as glycols and glycerins. . 6. The high reaction according to claim 1, wherein the amine is a primary amine, a secondary amine or a tertiary amine and is soluble in water. Method for producing hydrated slaked lime. 7. The method for producing highly reactive slaked lime according to claim 1, wherein the saccharide is a water-soluble saccharide such as sucrose, glucose and fructose.