KR100419634B1 - A removal method of h2s generated during preparing slag sands and an apparatus used in the method - Google Patents

Abstract

The present invention relates to a method for removing hydrogen sulfide generated during blast furnace manufacturing and an apparatus used therefor.

The molten slag discharged from the blast furnace is quenched and granulated with a high-pressure cooling water to produce blast furnace material, and when the molten slag is quenched in the cooling water, sulfur content contained in the slag comes into contact with water to discharge hydrogen sulfide-containing steam. In a manufacturing method,

Caustic soda is added to the cooling water, reacted with hydrogen sulfide, and caustic soda is added in an equivalent ratio to the hydrogen sulfide concentration discharged to the recovered cooling water. The caustic soda is recycled while maintaining according to the removal efficiency of hydrogen sulfide to obtain the pH of the cooling water. Remove the generated hydrogen sulfide.

Also provided is an apparatus for use in the hydrogen sulfide removal method.

According to the present invention, by effectively managing the amount of NaOH in the cooling water, only hydrogen sulfide, which is highly corrosive and causes odor generation, can be selectively and efficiently removed from the hydrogen sulfide mixed steam discharged from the slag sand production facility used in the related art.

Description

Method for removing hydrogen sulfide from blast furnace manufacturing and apparatus used therein {A REMOVAL METHOD OF H2S GENERATED DURING PREPARING SLAG SANDS AND AN APPARATUS USED IN THE METHOD}

The present invention relates to a method for removing hydrogen sulfide generated during blast furnace manufacturing and a device used therein, and more particularly, only hydrogen sulfide in hydrogen sulfide-containing steam discharged from a stack in a manufacturing plant using caustic soda. And a device used at this time.

Slag, which is a by-product of the production of pig iron in blast furnaces, is now aggregated in dry pit or slag sand in a water plant. The manufacturing process of such a hand material is summarized as follows.

When manufacturing iron in blast furnace of steel mill, stirring molten slag of blast furnace produced by oxidative and basic oxides such as SiO ₂ , Al ₂ O ₃ and MgO contained in iron ore and coke with lime It is fed to the middle of the bath, where the slag is quenched by direct contact with high pressure water.

The produced water and cooling water are kept at the bottom of the stirring tank and then sent to the separation tank by slurry pump to separate the water and the water, where the separated water is transported and reused where needed by the truck, and the cooling water is cooled in the cooling tower Recycled.

As such, when molten slag is quenched by the cooling water, sulfur content contained in the slag is oxidized and released into SO ₂ , or in contact with water to generate H ₂ S. The steam and hydrogen sulfide generated as described above are released into the atmosphere through the stack on the upper side of the agitator tank. The mixed gas of the released steam and hydrogen sulfide is highly corrosive to corrode the equipment prematurely, and odor due to the rotting smell of the hydrogen sulfide egg. Let's do it. Therefore, hydrogen sulfide must be removed.

In order to remove the hydrogen sulfide-containing steam thus generated, the steam is partially condensed in a receiver into which a water jet is introduced, followed by condensation by spraying water on residual steam and gas, and finally the remaining gas is recycled to the spray head. Method for producing slag sand (particles) from the furnace slag characterized in that it is disclosed in the Republic of Korea Patent No. 93-65086.

At this time, the hydrogen sulfide gas partially condensed in the receiver is removed by reacting with the Ca component in the slag.

In another prior art, Korean Patent Application No. 98-57559 shows an improved apparatus for treating steam and hydrogen sulfide generated during the process of manufacturing a water by using a water equipment that removes hydrogen sulfide more efficiently while removing steam. And methods are disclosed.

However, in general, the main cause of corrosion in the corrosion by the mixed gas of steam and hydrogen sulfide is hydrogen sulfide, and the hydrogen sulfide is also a cause of odor, whereas the apparatus disclosed by the above methods treats a mixture gas of hydrogen sulfide and steam, There is a problem that it takes a lot of money to put them to practical use.

Accordingly, an object of the present invention is to provide a method for selectively removing only hydrogen sulfide from the hydrogen sulfide-containing steam generated during blast furnace manufacturing.

Another object of the present invention is to provide a method for more efficiently removing hydrogen sulfide by effectively managing caustic soda.

Another object of the present invention is to provide a hydrogen sulfide removal apparatus that can achieve the above object.

1 is a view schematically showing an apparatus for removing hydrogen sulfide generated in a blast furnace remanufactured by the present invention in the reclaim stack;

2 is a graph comparing the concentration of hydrogen sulfide discharged after adding caustic soda and the concentration of hydrogen sulfide discharged without adding caustic soda according to the present invention according to the present invention;

3 is a graph comparing the input of caustic soda to be maintained in the cooling water with the highest concentration of hydrogen sulfide to be discharged according to the present invention.

* Brief description of the main parts of the drawing

1 ... Recyclable Stack 2 ... Slurry Pump

3 ... Dewatering Hopper 4 ... Truck

5 ... Hot Water Pond 6 ... Cold Water Pond

7 ... hot water pump 8 ... cooling tower

9 ... coolant supply pump 10 ... caustic soda storage tank

11 ... caustic soda supply pump 12 ... caustic soda supply piping

13 ... caustic soda flow meter 14, 15 ... pH meter

16. Chilled water supply piping

According to one aspect of the invention,

The molten slag discharged from the blast furnace is quenched and granulated with a high-pressure cooling water to produce blast furnace material, and when the molten slag is quenched in the cooling water, sulfur content contained in the slag comes into contact with water to discharge hydrogen sulfide-containing steam. In a manufacturing method,

Adding caustic soda to the cooling water, reacting with hydrogen sulfide, and recovering the caustic soda-containing cooling water;

Measuring pH of the recovered cooling water, and then adding caustic soda in an equivalent ratio to the discharged hydrogen sulfide concentration to maintain the pH according to the required removal efficiency of hydrogen sulfide; And

There is provided a method for removing hydrogen sulfide generated during blast furnace manufacturing, consisting of: repeating the process by recycling the cooling water adjusted pH.

According to the second aspect of the present invention,

Blast stack (1) for producing the blast furnace, hot water pond (5) for storing the remaining coolant after reacting with hydrogen sulfide from the stack (1), cooling tower for cooling the cooling water in the hot water pond ( 8) In the water stack consisting of a cold water pond (6) for storing the cooling water cooled in the cooling tower (8) and a cooling water supply pipe (16) for supplying cooling water from the cold water pond (6) to the water stack (1) In the device for removing the hydrogen sulfide generated,

Caustic soda flow rate in the caustic soda supply pipe 12, the caustic soda supply pipe 12 connected to the cooling water supply pipe 16, the pH meter 14 is mounted to the cold water pond 6 to measure the pH of the cooling water Caustic soda flow meter 13, caustic soda storage tank 10 for introducing caustic soda through the caustic soda supply pump 11 according to the flow rate measured by the flow meter 13 and the cooling water supply pipe There is provided a re-stack generating hydrogen sulfide removal device composed of a pH meter 15 for measuring the pH of the cooling water recycled at (16).

Hereinafter, the present invention will be described in detail with reference to FIG. 1.

In the present invention, when the molten slag is quenched, the pH in the water stack generating gas removal apparatus is optimally maintained, and as a result, NaOH is effectively managed to efficiently remove only hydrogen sulfide from the hydrogen sulfide-containing steam.

Referring to the process of adding caustic soda in the present invention, first, the caustic soda stored in the caustic soda storage tank 10 by the caustic soda supply pump 11 through the caustic soda supply pipe 12 through the cooling water supply pump ( Caustic soda is diluted in the cooling water by injecting it into the cooling water supply pipe 16 at the end of step 9).

As described above, by adding caustic soda to the cooling water, H ₂ S generated when the sulfur content and water contained in the molten slag meet in the stack 1 is reacted with NaOH at the same time to generate Na ₂ S or NaHS. Is switched.

This is represented by the following scheme.

2NaOH + H ₂ S → Na ₂ S + 2H ₂ O

Na ₂ S + H ₂ S → 2NaHS

Therefore, in the cooling water after the reaction, unreacted NaOH, Na ₂ S generated by the reaction scheme 1 and NaHS generated by the reaction scheme 2 coexist.

In order to enable the reactions of Schemes 1 and 2 to occur smoothly, it is preferable that the NaOH initially introduced into the cooling water through the caustic soda storage tank 10 is excessive. Even if an excess amount is added, there is no loss in quantity because unreacted NaOH contained in the cooling water after the reaction is stored in the cold water pond 6 and recycled only by the optimum amount (described later).

At this time, H ₂ S, Na ₂ S and NaHS remaining in the cooling water is stored in the cold water pond 6 and recycled together with the cooling water, some of which is discharged through the dehydrator with the water can be recycled to the cement raw material.

As such, the pH of the cooling water stored in the cold water pond 6 is measured by the pH meter 14 mounted on the cold water pond 6, and then the hydrogen sulfide requiring the pH value re-measured in the cooling water supply pipe while recirculating the cooling water is removed. It is preferable to maintain according to the efficiency. The pH is preferably maintained at 11 or more, preferably 11.5 or more. In the pH range, the hydrogen sulfide removal efficiency generated in the stack can be effectively controlled to 85% or more.

In order to maintain the pH in this manner, the present invention is not limited thereto, but the concentration of hydrogen sulfide discharged from the upper portion of the stack 1 can be measured, and caustic soda can be added at an equivalent ratio.

That is, assuming that 1 mole of caustic soda should be added to remove 1 mole of hydrogen sulfide, dividing the hydrogen sulfide emissions by caustic soda concentration can calculate the amount of caustic soda required for the reaction, for example, the hydrogen sulfide measured in the stack (1). The optimum caustic soda dose can be calculated by substituting the discharge concentration into Equation 1 below.

Optimal NaOH input (ℓ / min) = discharge concentration (mol / m ³ ) x air inflow (m ³ / min) x NaOH molecular weight (g / mol) / caustic soda concentration (g / ℓ)

Then, the cooling water stored in the caustic soda storage tank 10 is recycled by adjusting and recirculating the optimum NaOH input amount obtained as described above through the caustic soda flow meter 13 to optimally manage the amount of NaOH retention in the cooling water used during the reaction. . That is, the pH of the cooling water to be recycled can be optimally maintained. In addition, to check this, the pH should be measured by a pH meter 15 mounted on the cooling water supply pipe 16.

At this time, the concentration of caustic soda to be maintained in the cooling water is preferably at least 22 ppm, as can be seen from the data of FIG.

As in the present invention, by diluting caustic soda in the cooling water, sulfur content present in the molten slag reacts with the cooling water to produce hydrogen sulfide and is removed at the same time, and the remaining NaOH-containing cooling water is controlled to maintain the proper pH so that the molten slag is quenched with the cooling water. Can remove most of the hydrogen sulfide produced.

In this way, hydrogen sulphide generated during blast furnace remanufacture is mostly removed by NaOH injected into the cooling water, and even if a small amount of hydrogen sulphide is discharged to the top of the remnant stack, its emission is extremely small, thus significantly reducing the corrosion rate of the surrounding equipment. , Get rid of bad smell.

Hereinafter, embodiments of the present invention will be described in detail. The following examples are intended to illustrate the invention and are not intended to limit the invention thereto.

<Example 1>

In this embodiment, the effect of reducing the concentration of hydrogen sulfide generated during blast furnace material manufacturing by introducing caustic soda into the cooling water will be described.

45% NaOH was added at 22ppm, 56ppm, 74ppm and 96ppm to the cooling water to be supplied to the water stack 1 of the present invention, and then the discharge concentration of hydrogen sulfide was measured at the top of the water stack 1 and the result is illustrated. 2 is shown.

Also, for comparison, the concentration of hydrogen sulfide discharged from the top of the stack 1 after treatment in the water stack 1 without adding caustic soda to the cooling water was measured and the results are shown in FIG. 2.

As can be seen from the figure, when the caustic soda is not added, it can be seen that as the treatment time increases, the slag emission increases and the hydrogen sulfide concentration increases.

On the contrary, according to the method of the present invention in which caustic soda is added, it can be confirmed that the discharge concentration of hydrogen sulfide is maintained in a significantly reduced state.

<Example 2>

In this embodiment, the optimum NaOH dose to be maintained in the cooling water to determine the hydrogen sulfide is determined.

While repeating the experiment of Example 1, while maintaining the pH of the cooling water in the cold water pond (6) 1 recycle the cooling water so that the sodium hydroxide contained in the water stack (1) always maintains a certain amount of hydrogen sulfide discharge concentration Was measured and the result is shown in FIG.

As shown in the figure, it can be seen that by adding the new input and recycle amount in the cooling water, more than 85% of hydrogen sulfide is removed when the caustic soda amount is maintained at 22 ppm or more. The above range is to satisfy the discharge allowable level, and thus it can be seen that maintaining a constant amount of caustic soda in the cooling water can prevent corrosion of the device and stably remove hydrogen sulfide.

As described above, by effectively managing NaOH added to remove hydrogen sulfide, only hydrogen sulfide, which is highly corrosive and causes odor generation, in the steam and hydrogen sulfide mixture discharged from a conventional slag sand production facility is selectively and efficiently removed. can do.

Claims (3)

The molten slag discharged from the blast furnace is quenched and granulated with a high-pressure cooling water to produce blast furnace material, and when the molten slag is quenched in the cooling water, sulfur content contained in the slag comes into contact with water to discharge hydrogen sulfide-containing steam. In a manufacturing method, Adding caustic soda to the cooling water, reacting with hydrogen sulfide, and recovering the caustic soda-containing cooling water; Measuring pH of the recovered cooling water, and then adding caustic soda in an equivalent ratio to the discharged hydrogen sulfide concentration to maintain the pH according to the required removal efficiency of hydrogen sulfide; And Recirculating the cooling water to adjust the pH to repeat the process; hydrogen sulfide removal method generated in the blast furnace material manufacturing consisting of The method of claim 1, wherein the caustic soda added to initiate the reaction is added in an excess amount equivalent to the hydrogen sulfide to be removed. Blast stack (1) for producing the blast furnace, hot water pond (5) for storing the remaining coolant after reacting with hydrogen sulfide from the stack (1), cooling tower for cooling the cooling water in the hot water pond ( 8) In the water stack consisting of a cold water pond (6) for storing the cooling water cooled in the cooling tower (8) and a cooling water supply pipe (16) for supplying cooling water from the cold water pond (6) to the water stack (1) In the device for removing the hydrogen sulfide generated, Caustic soda flow rate in the caustic soda supply pipe 12, the caustic soda supply pipe 12 connected to the cooling water supply pipe 16, the pH meter 14 is mounted to the cold water pond 6 to measure the pH of the cooling water Caustic soda flow meter 13, caustic soda storage tank 10 for introducing caustic soda through the caustic soda supply pump 11 according to the flow rate measured by the flow meter 13 and the cooling water supply pipe Water stack generation hydrogen sulfide removal device consisting of a pH meter (15), for measuring the pH of the cooling water recycled in 16