KR101052259B1 - How to remove carbonate and metal ions in Hwaseong factory - Google Patents

Abstract

It is an object of the present invention to provide a method for removing carbonate and metal ions that can effectively remove carbonate and metal ions contained in Hwaseong factory ordination used for COG purification through a single process.

In the method for removing carbonate and metal ions in the ordination for this purpose, at least one ion of calcium ions, barium ions, strontium ions, magnesium ions to the ordination in the chemical reaction tank is administered so that 15% or more of the equivalent of the carbonate ions Mixing and reacting, separating the precipitated particles precipitated in the reaction tank by the chemical reaction from the ordinal water using a centrifugal filter, and removing the metal ions in the ordinal water from which the precipitated particles are separated in the electrode reactor. And removing the electrode by electrode reaction.

Coke Oven Gas, Ordination, Nongsu, Denerd, Coke, Emulsified Hydrogen Gas

Description

Elimination Method for Carbonate and Metallic Ion in Ammonia Liquor at Chemical By-Product Plant

1 is a process flow diagram illustrating a carbonate and metal ion removal process according to the present invention,

2 is a graph showing the removal rate of carbonate ions in the ordination according to Example 2,

3 is a graph showing the removal rate of metal ions in the ordination according to Example 3.

The present invention relates to a method for removing carbonate and metal ions contained in ordination of a chemical by-product plant, and more specifically, for coke oven gas (COG) purification, in particular emulsification. The present invention relates to a method for removing carbonate and metal ions contained in ordination of a Hwaseong plant used as an absorption neutralizer for removing hydrogen gas.                         

The tar and water in the COG, tar, and moisture generated in the coal drying process for manufacturing coke are recovered and processed in the liquid phase, and the gaseous COG is collected and used as an energy source in steel mills. At this time, the carbon dioxide contained in the COG lowers the calorific value of the energy source, while the ammonia and hydrogen sulfide gas contained in the COG generate SOx and NOx during combustion, causing air pollution.

In addition, water contains various compounds produced by chemical reactions in coke distillation, and especially a large amount of ammonia is called ordination. Such ordination is used as an absorbent neutralizer to remove the hydrogen sulfide gas and the like in COG. Carbonic acid and metal ions contained in large quantities in the ordinal water cause problems in the COG gas purification process.

That is, when the concentration of carbonate ions is high in the ordinal water used in the hydrogenated hydrogen scrubber, which is a gas treatment process, the carbonate ions interfere with the movement due to the difference in concentration of the hydrogen sulfide contained in the COG. The metal ions in the ordination react with the ammonium ions in the ordination to form metal ammonium salts, which act as the main cause of the process pipe closure.

In detail, the carbonate and metal ions contained in ordination are distilled from ammonia steel, and the ammonia gas (concentration 12-14 g / l) generated from the ordination is concentrated in a desorter (concentration 17-20 g / l). The concentration of carbonate ions contained in these Nongyi water is 3.5 g / ℓ, metal ions are mainly iron ions concentration of 3000 ~ 6000 ppm, zinc ions, copper ions contained within 30ppm.                         

Therefore, there is a need for a method that can reduce the COG purification efficiency and remove the carbonate and metal ions together causing the process pipe closure.

The present invention has been proposed to solve the above problems, a method of removing carbonate and metal ions that can effectively remove the carbonate and metal ions contained in the Hwaseong factory ordination used for COG purification through a single process. For the purpose of providing it.

Method for removing carbonate and metal ions contained in the ordination of Hwaseong factory according to the present invention for achieving the above object, at least one ion of calcium ions, barium ions, strontium ions, magnesium ions in the ordination in a chemical reaction tank Mixing and reacting by administering an excess of 15% or more of the equivalent of the carbonate ion, and separating precipitated particles precipitated in the reactor by the chemical reaction from the ordinal water using a separation filter, in the electrode reactor. It characterized in that it comprises the step of electrodepositing and removing the metal ions in the ordination, the precipitated particles are separated by the electrode reaction.

The above chemical reaction and electrode reaction can be carried out in the same reactor.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As can be seen in Figure 1, the ordination generated in the coke manufacturing process is prepared as ordination for COG purification by combining a desorator to concentrate ammonia in the ordination and ammonia steel to distill the ammonia in the ordination. At this time, the ordination from which ammonia has been degassed through the distillation process is called de-eye, and the ordination with ammonia-concentrated in the concentration process is called non-eye.

Carbonate ions and metal ions contained in these arid waters cause problems in the process, and the carbonate ions are removed by separating the carbonate ions in the ordination into solid particles in the form of carbonates by chemical reaction, and the metal ions are subjected to the electrode reaction. The metal ions in the ordination from which the carbonate ions have been removed are removed by electrodeposition to the electrodes. Examine the specific process.

[Chemical reaction]

Calcium hydroxide (Ca ⁺² ) is mainly used to remove carbonate ions contained in ordination in the form of poorly soluble compounds of carbonate, and barium ions (Ba ^{+ 2} ), strontium ions (Sr ^{+ 2} ), and magnesium ions (Mg ⁺ Cations such as ² ) may be used.

Carbonate ion (HCO ₃ ^-) are present in the ordination forms a precipitate particles by the following chemical reactions, such can be easily removed through the filtered.

HCO3 ^- + Ca ⁺² --------------> ₃ CaCO (solid) + H ⁺

Separation of Precipitated Particles                     

Various filters may be used to separate the produced solid precipitated particles from the filtrate, but the simple separation and filtration using a centrifugal filter is effective for process efficiency. Sediment in the ordinal water filtered by the centrifugal filter is discharged to the outside, and the filtrate can be circulated directly in the process.

[Electrode reaction]

The electrochemical reaction to remove metal ions in the ordination from which carbonates are removed is removed by the electrodeposition of metal ions, which are cations on the negative electrode surface, especially in the case of Fe ions present in large quantities in ordination. same.

Fe ⁺² + 2e -------------> Fe (electrode to metal)

Fe ⁺³ + 3e -------------> Fe (electrode with metal)

This electrochemical reaction can be carried out using the above chemical reaction tank.

On the other hand, in order to increase the collection efficiency of the ordination for hydrogen sulfide contained in the COG, the temperature of the treated ordination plays an important role. If the temperature of the ordination is high, the vapor pressure is increased and the collection reaction speed is lowered to reduce the collection efficiency.

Therefore, the ordination, which has undergone the above-described treatment, is preferably managed at 23 ° C. or lower by passing through a heat exchanger to efficiently reduce the concentration of hydrogen sulfide in COG.

It looks at a specific embodiment according to the present invention below.                     

Example 1

In this embodiment, as an example for removing carbonate ions contained in the ordination, first, a sample solution of the concentrated eye water was taken and chemical analysis was performed. The results are shown in Table 1 below.

Table 1

Chemical composition Free ammonia
(Free Ammonia) Carbonate ion (HCO ₃ ^-) Unit (g / ℓ)           18.12           3.5  Molarity (M)            1.07           0.0795

For the experiment of removing carbonate ions in ordination having these chemical components, 15 liters of the sample solution was used to adjust the equivalent of carbonate ions contained in the ordination using saturated calcium hydroxide solution (0.165 g / 100 g water). The reaction was further subdivided into reaction cases in which 10%, 15%, 20%, and 25% were added. After the reaction, each sample was centrifuged and the filtrate was collected to analyze the concentration of carbonate, and the results are shown in FIG. 2.

As can be seen in Figure 2, when the equivalent reaction of the carbonate ions has a lot of interference factors, the actual removal rate appeared to be about 67%, but when administered over 15% of the carbonate ions The removal rate was over 90%. Therefore, in order to remove carbonate ions contained in the ordination, it is preferable to administer an amount exceeding 15% of the equivalent of carbonate ions.                     

Example 2

This embodiment looks at the conditions for removing metal ions in the filtrate after removing carbonate ions contained in the ordination in the electrode reactor. Carbonate ions are removed, that is, the initial metal ion concentration in the electrode reaction is shown in Table 2 below.

Table 2

ingredient T- Fe ion Cu Zn Mn Concentration (ppm) 4530 3 12 10

The 5 L electrode reactor was supplied with 3 L of carbonate deionized water removed, and the test was performed by applying DC 7V to the cathode and the anode. The surface area of the anode was 400 cm ² for 30 minutes at intervals of 5 minutes, and then samples were taken to measure the removal rate of metal ions. The results are shown in FIG. 3 in terms of metal ion removal rate.

As can be seen in Figure 3, less than 15 minutes, the metal ion removal efficiency appeared to be very low, at 15 minutes or more showed more than 90% metal ion removal rate. Therefore, during the electrode reaction, there is an efficient area where the electrode reaction should be carried out for a predetermined time, and it can be confirmed that the electrode ion can be removed by electrodeposition of metal ions.

Example 3

In this embodiment, the concentration of ammonia contained in each of the filtrate (refined ordination) from which the carbonate and metal ions contained in the ordination are removed, and the ordination (non-purified ordination) which does not remove the carbonate and metal ions are 19.0. It was adjusted to a constant g / ℓ, the experiment was performed to remove the hydrogen sulfide gas contained in the COG using each sample. COG used a standard sample gas containing 0.05% by volume of hydrogen sulfide gas in COG.

In the experimental method, 10 l of purified and unrefined ordination samples were sprayed in COG circulating in a circulation system at 50 ml / min. After circulating COG for 30 minutes, the concentration of hydrogen sulfide contained in COG was measured. The results are shown in Table 3 below.

Table 3

sample Content in Initial COG Ordination Unrefined ordination Hydrogen sulfide concentration
(volume%) 0.05 0.008 0.018

As can be seen in Table 3, when using unrefined ordination without removing carbonate and metal ions, the hydrogen sulfide gas removal rate is about 64%, and when the purified eye according to the present invention is used, the hydrogen sulfide gas removal rate is As 84%, it can be seen that the removal rate of the hydrogen sulfide gas is improved by about 20% compared to the case of using unrefined ordination when using purified ordination.

According to the method of removing carbonate and metal ions as described above, it is possible to simply remove carbonate and metal ions contained in the ordination through a single process, so that the collection rate of hydrogen emulsion contained in COG is It is possible to reduce the amount of hydrogen gas in the COG used as fuel in steel mills, thereby reducing the amount of SOx generated during combustion, and metal ions react with ammonium ions in ordination to form metal ammonium salts, causing pipe closing. Can be suppressed.

Claims (1)

In the method for removing carbonate and metal ions contained in Hwaseong factory ordination, In a chemical reaction tank, mixing and reacting the ordination by administering one or more ions selected from calcium ions, barium ions, strontium ions, and magnesium ions to an amount of at least 15% more than the equivalent of carbonate ions; Separating the precipitated particles precipitated in the reaction tank by the chemical reaction of the previous step from the ordinal water using a separation filter; And In the electrode reactor, the metal ions in the ordination in which the precipitated particles are separated by the electrode reaction to remove the electrode by the electrode reaction;

Images