JP2000198986A - Process for removing settlings in ammonia liquor in coke oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove settlings suspended or floating in ammonia liquor without generating an emulsion. SOLUTION: When separating a coal tar layer 9 and an ammonia liquor layer 11 by introducing coal tars generated from a coke oven l into a coal tar decanter 8, a lipophilic emulsion breaker is directly added to the coal tar decanter 8 from an emulsion breaker tank 12 via a quantitative pump. An emulsion generated using settlings present in ammonia liquor as media is efficiently broken, and settlings are removed from ammonia liquor. Since the amount of the lipophilic emulsion breaker added is extremely small, a large effect is achieved at a low operation cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing slag suspended or suspended in low-temperature coke ovens when coal tar generated from a coke oven is separated from the low-temperature water by standing. It relates to a removal method.

[0002]

2. Description of the Related Art As shown in FIGS. 1 and 2, a high-temperature gas 13 generated when coal is charged into a coke oven 1 and carbonized is
Cooling is performed by spraying water from a water nozzle 14 disposed in the curved section 3 of the riser 2. During this cooling, coal tar components are condensed, and pulverized coal and semi-coke powder and the like entrained in the gas (hereinafter, pulverized coal and semi-coke powder and the like are referred to as slag) are captured. It flows down the lower part of main 5 to coal tar decanter 8. The sedimentation and separation are performed in the coal water decanter while the coal tar is stationary in the deionized water. At this time, it is known that an emulsion layer 10 (emulsion layer) is formed between the upper water layer 11 and the lower coal tar layer 9.

[0003] The emulsion layer is formed by complexly mixing coal tar and cheap water through slag entrained by gas. The formation of this emulsion layer is remarkably observed in a coke oven into which coal whose moisture has been adjusted by drying or preheating (hereinafter referred to as humidified coal) is charged. There is a problem that the slag suspended or suspended in the emulsion layer or the dehydrated water layer needs to be drawn out of the system in order to stay in the pipe for transporting deionized water or to close the deionized water nozzle.

[0004] In order to solve this problem, for example, JP-A-9-291293 discloses that an emulsion layer formed by a coal tar decanter is quickly taken out of the decanter, centrifuged after adding water outside the system. A method is disclosed. Japanese Patent Publication No. 59-45033 discloses that an emulsifier (saturated hydrocarbons, halogenamines, polymerized ethers, etc.) is used in the process from the curved portion of the riser to the coal tar decanter.
(A mixture of phenol-formaldehyde condensates) to prevent the formation of emulsions in the coal tar decanter.

[0005]

However, in the former, there is a problem that equipment such as a centrifugal separator for separating outside the system is required, and the installation space cannot be secured in the existing coke oven equipment. Even in the latter case, the emulsifier is transported to the bent portion of the riser pipe located at a high place, which requires installation of tanks, pipes and pumps, both of which are disadvantageous in terms of equipment and economy. Also, in the latter case, since the curved portion of the riser is at a high temperature of 700 to 800 ° C., the added emulsifying agent is decomposed, so that the breaking ability is reduced,
In order to suppress the generation of the emulsion, there is a problem that the effect cannot be obtained unless the added amount is increased.

The present invention has been made to overcome the above-described circumstances, and has as its object to provide a method for efficiently removing slag in deionized water without decomposing a demulsifier. is there.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for separating coal tar generated from a coke oven into coal tar and low-temperature water by a stationary separator. A method for removing slag in stagnant water in a coke oven, characterized by adding a lipophilic demulsifier to the water.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a generated gas (coke gas) 13 generated from a coke oven 1 into which coal such as humidified coal is charged is high in temperature and contains a large amount of slag (pulverized coal or semi-coke powder). The cooling water is cooled by the cooling water sprayed from the cooling water nozzle 14 disposed in the curved pipe section 3 of the riser pipe 2. Coal tar components are condensed during the cooling with the low temperature water, and the slag entrained by the generated gas 13 is captured.
The coal tar which has captured the slag is settled in low-temperature water, flows down the lower part of the dry main 4 and the lower part of the suction main 5 and is introduced into a coal tar decanter 8 which is a kind of stationary separator.

[0009] As the low-temperature water sprayed to the curved pipe section 3, low-temperature water from which the residue existing in the upper layer of the coal tar decanter 8 has been removed is circulated to the low-pressure nozzle 14 via the low-pressure pump 16 and supplied. On the other hand, the generated gas 13 is guided to the primary gas cooling equipment 6 via the suction main 5 and cooled, and is sent to the next process via the gas blower 7. The coal tar that has captured the slag is sedimented and separated into low-temperature water and coal tar in a stationary state in the coal tar decanter 8. At this time, as in the conventional embodiment shown in FIG. 2, if a large amount of trapped slag is present, the slag is used as a medium to form a complicated mixture of the water and the coal tar, and the upper water layer 11 and the lower coal tar layer 9 are mixed. As described above, the emulsion layer 10 is formed in the middle of the above.

According to the present invention, an emulsifier is installed in the vicinity of the coal tar decanter 8 to store the lipophilic emulsifier, and the lipophilic emulsifier is added directly to the coal tar decanter 8 by the metering pump 15. I do. As a result, the emulsified layer forming the emulsion layer 10 is destroyed, and the slag suspended or suspended in the water is settled in the coal tar layer 9 to remove the scum from the water. Here, the large slag sinks to the bottom of the coal tar decanter 8, and the slag is discharged out of the system using a scraper or the like. Further, small slag floating in the coal tar layer 9 can be removed by pumping out the coal tar layer 9 and centrifuging in the next step.

Since the temperature of coal tar and the temperature of the deionized water flowing into the coal tar decanter is usually about 80 ° C., the demulsifier is not decomposed. The lipophilic demulsifier is not particularly limited as long as it has a property of destroying the emulsified layer that is generated. For example, a lipophilic demulsifier composed of a mixture of a formalin condensate of an alkylphenol and a polymerized ether can be exemplified.

As the lipophilic demulsifier, 1 g of an emulsifier is dissolved in a mixed solvent of dioxane (60% by volume) and phenyl cellosolve (40% by volume) at 20 ° C.
It is preferable that the water No. measured by the amount (ml) of water that has become cloudy be in the range of 10 to 50. The reason for setting the water No. in the range of 10 to 50 is that if it exceeds 50, the hydrophilicity becomes strong and the effect of preventing the generation of emulsion tends to be insufficient, and if it is less than 10, the dispersion in the process tends to deteriorate. .

Further, the addition amount of the lipophilic demulsifier is
Depends on the demulsifier used, but generally 0.01 to 0.08% by weight based on the coal tar generated from the coke oven
To the range. Here, when the amount of addition exceeds 0.08% by weight, the effect of preventing the generation of emulsions reaches a peak and is uneconomic. When the amount is less than 0.01% by weight, the effect of preventing the generation of emulsions is not sufficient. In the present invention, it is important that the lipophilic demulsifier is added directly to the coal tar decanter 8 as the demulsifier, and an anionic hydrophilic demulsifier is not used because the destruction effect is extremely low.

In a coke oven charged with humidified coal, a lipophilic emulsifier (Water No. 20) comprising a mixture of a formalin condensate of an alkylphenol and a polymerized ether according to the present invention (Water No. 20) is supplied from a demulsifier tank 12 An experiment was conducted in which 0.02% by weight of coal tar generated from a coke oven was added to the water layer 11 of the coal tar decanter 8.
I went there. For comparison, an experiment in which no emulsifier was added and an experiment in which a hydrophilic emulsifier was added were performed four times. The results are shown in FIG. In FIG. 3, experiment Nos. 1 to
4 shows the case of adding the lipophilic demulsifier of the present invention, Experiment Nos. 5 to 8 show the conventional examples without emulsifier, and Experiment N
o.9 to 12 are trade names of hydrophilic emulsifiers such as Demalfer TM-12 (manufactured by Toho Chemical Co., Ltd.)
The comparative example which adds the amount equivalent to weight% is shown.

As shown in FIG. 3, in the case of the conventional example in which the demulsifying agent was not added and in the comparative example in which the hydrophilic demulsifying agent was added, the ratio of the slag in the tap water was 0.1 to 0.2% by weight. Thus, according to the example of the present invention, it was possible to significantly reduce the amount to 0.01% by weight or less, and the formation of an emulsion was eliminated.

[0016]

As described above, according to the present invention, when coal tar generated from a coke oven is separated into coal tar and low-temperature water by a stationary separator, lipophilic emulsification occurs in the stationary separator. The addition of the breaking agent allows the emulsion breaking agent to be efficiently destroyed without decomposing the slag existing in the tap water as a medium, and the slag can be removed from the tap water. Further, since the addition amount of the lipophilic demulsifier is extremely small, the operation cost can be reduced and the economic effect is great.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a conventional embodiment.

FIG. 3 compares the ratio (% by weight) of slag in the water in the case of the present invention in which a lipophilic emulsifier is added, the conventional example in which no emulsifier is added, and a comparative example in which a hydrophilic emulsifier is added. It is a bar graph shown.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coke oven 2 Rise pipe 3 Curved pipe part 4 Dry main 5 Suction main 6 Primary gas cooling equipment 7 Gas blower 8 Coal tar decanter 9 Coal tar layer 10 Emulsion layer 11 Water layer 12 Emulsifier tank 13 Generated gas 14 Nozzle 15 Metering pump 16 Water pump

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazunori Oda 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama (No address) Kawasaki Steel Corporation Mizushima Works F-term (reference) 4H012 LA00

Claims (1)

[Claims] When a coal tar generated from a coke oven is separated into coal tar and low-temperature water by a stationary separator, a lipophilic demulsifier is added into the stationary separator. A method for removing slag in stagnant water in a coke oven.