KR20080087969A - A desulfurizing sorbent for so2 removal and a process for the preparation thereof - Google Patents

Abstract

A high efficiency low temperature dry type desulfurizing sorbent that removes SO2 efficiently even in a low temperature range is provided, a desulfurizing sorbent that is utilized in other uses even after absorbing SO2 is provided, and a process for the preparation of the desulfurizing sorbents is provided. A desulfurizing sorbent for SO2 removal comprises: an alkali-based metal as an absorption component for absorbing SO2; and a metal oxide as a support component in which the alkali-based metal is dispersed. A process for the preparation of a desulfurizing sorbent for SO2 removal comprises: a first step of preparing an alkali-based metal precursor solution in the amount of 0.1 to 40% by weight of the total sorbent weight; a second step of adding a metal oxide powder as a support component into the solution, and agitating a mixture of the solution and the metal oxide powder to prepare a suspension; a third step of impregnating the suspension with an alkali-based metal by using a rotary vacuum concentrator; and a fourth step of firing the dried sorbent powder after drying a sorbent powder formed by the impregnation. A process for the preparation of a desulfurizing sorbent for SO2 removal comprises: a first step of mixing an alkali-based metal powder in the amount of 0.1 to 40% by weight of a support component with a metal oxide powder that is the support component; a second step of adding an organic binder into the mixed powder to mix the organic binder with the mixed powder; and a third step of firing the dried mixture after drying a mixture prepared in the second step. Further, the metal oxide is one or a mixture selected from alumina, titania, zirconia and magnesia.

Description

Desulfurization absorber for removing sulfur dioxide and its manufacturing method {A DESULFURIZING SORBENT FOR SO2 REMOVAL AND A PROCESS FOR THE PREPARATION THEREOF}

1 is a graph showing the desulfurization performance according to the water content of the potassium carbonate-based desulfurization absorbent prepared according to an embodiment of the present invention.

Figure 2 is an X-ray diffraction analysis showing that after the potassium carbonate-based desulfurization absorber prepared according to an embodiment of the present invention completes the absorption of sulfur dioxide, all potassium carbonate is converted to potassium sulfate.

The present invention relates to a desulfurization absorber for removing the combustion exhaust gas and sulfur dioxide gas present in the atmosphere, and more particularly, to a low temperature close to room temperature, including an absorbent component for absorbing sulfur dioxide and a support component for dispersion of the absorbent component. The present invention relates to a desulfurization absorber capable of absorbing sulfur dioxide in the region.

Sulfur dioxide gas, which occupies most of air pollutants, causes smog and acid rain and is very harmful to human body when exposed to sulfur dioxide gas. Therefore, efforts to remove sulfur dioxide gas have been continued. Currently, to remove sulfur oxides, a flue gas desulfurization system is mainly used, which is classified into a wet method and a dry method according to the type of absorbent, and is divided into a regeneration method and a non-regeneration method according to the recovery and utilization of the reaction product. do. The wet method is used to remove a large amount of sulfur dioxide generated in industrial processes such as thermal power generation. Among these, wet limestone scrubbing with forced oxidation is not only simple, but also expensive to use. Inexpensive and abundant, it is widely used to occupy more than 80% of the total installed capacity, the removal of sulfur dioxide using the flue gas desulfurization facility has the advantage of producing high-quality gypsum as a by-product. In addition, various wet removal methods using alkali metals have been proposed. EP0211458 circulates a suspension or aqueous solution mixed with Na ₂ O, NaOH, K ₂ O, Na ₂ CO ₃ , K ₂ CO ₃ , CaO, etc. in a fluidized bed reactor. SO ₂ from flue gas A method of removing is disclosed, EP0451715 describes a method of treating CO ₂ and SO ₂ using an aqueous solution containing K ₂ CO ₃ or KH ₂ CO ₃ and water, and in JP55020608, K ₂ CO ₃ is used to remove SO ₂ and NO x. A method of using an aqueous solution containing ₂ SO ₃ and a Fe component is disclosed. However, the wet removal method using an alkali metal belongs to the non-regeneration method and thus has problems such as transportation and disposal costs in the treatment of the waste solution.

The dry removal method mainly uses an absorbent, and a general metal oxide type absorbent is mainly used in a high temperature region. In the low temperature region, alkali metal is added to a porous material having a large specific surface area, such as activated carbon, and has a lower removal rate than a high temperature dry absorbent and a wet method. In Korean Patent No. 270092, a polyacrylonitrile-based activated carbon fiber adsorbent was used. In JP4059046, activated carbon was soaked in KlO ₃ , K ₂ CO ₃ , dried, and then prepared in a honeycomb form to obtain SO ₂ , HCl, and HF. Removal method was used. Also high for a clean room that requires a clean air quality activated carbon and ion exchange resin using a can remove SO ₂ so that the number of ppb level, the number of ppm of SO ₂ at room temperature region. However, periodic replacement due to limitations in the ability to absorb work Is required.

The present invention is to solve the above problems, to provide a high-efficiency low-temperature dry desulfurization absorber that can efficiently remove sulfur dioxide even in a low temperature region.

In addition, the present invention is to provide a desulfurization absorber that can be utilized for other purposes even after absorbing sulfur dioxide.

Desulfurization absorbent for removal of sulfur dioxide of the present invention for achieving the above object,

Alkali metals as absorption components for absorbing sulfur dioxide; And

It comprises a metal oxide as a support component in which the said alkali type metal is disperse | distributed.

The alkali-based metal as the absorbent component may be, for example, one or a combination of two or more selected from alkali-based metals capable of absorbing sulfur dioxide such as potassium carbonate, potassium hydroxide, potassium oxide, potassium bicarbonate, and the like, preferably potassium carbonate. . In addition, the metal oxide as the support component may be one or a combination of two or more selected from metal oxides capable of dispersing an absorbent component such as alumina, titania, zirconia, and magnesia, or may be activated carbon.

The content of the alkali metal, which is an absorbent component of the desulfurization absorbent for removing sulfur dioxide of the present invention, is 0.1 to 40% by weight of the total weight of the absorbent, and preferably 30% by weight. When the content of the alkali metal exceeds 40% by weight, the dispersibility of the alkali metal decreases, which may inhibit the sulfur dioxide absorption efficiency of the absorbent.

By using the support component, the absorbent component can be dispersed in the support component having a large surface area, thereby increasing the reactivity of the absorbent component.

The desulfurization absorber for removing sulfur dioxide of the present invention can be prepared by two methods, an impregnation method and a physical mixing method.

The manufacturing method by the impregnation method of the desulfurization absorbent for removal of sulfur dioxide of the present invention,

A first step of preparing an alkali-based metal precursor solution of the absorbent component of 0.1 to 40% by weight of the total weight of the absorbent;

Adding a metal oxide powder as a support component to the solution, followed by stirring to prepare a turbid solution;

A third step of impregnating the turbid liquid with an alkali metal using a rotary vacuum concentrator; And

And a fourth step of drying and then firing the absorbent powder formed after the impregnation.

The manufacturing method by the physical mixing method of the desulfurization absorber for removal of sulfur dioxide of the present invention,

A first step of mixing the alkali-based metal powder of the absorbent component of 0.1 to 40% by weight of the total weight of the absorbent and the metal oxide powder of the support component;

A second step of adding and mixing an organic binder to the mixed powder;

And a third step of drying and then firing the mixture prepared in the second step.

As described above, the desulfurization absorber for removing sulfur dioxide of the present invention is applicable to all sources in which sulfur dioxide is generated. When using the desulfurization absorber of the present invention, sulfur dioxide in the air is in a wide temperature range of about 10 ° C to 150 ° C. It can be removed, in particular in the low temperature region, including room temperature of 25 ℃ to 60 ℃.

Hereinafter, the production method of the absorbent for removing the sulfur dioxide of the present invention and the performance of the prepared absorbent will be described through Examples.

In the Examples, the absorbents prepared by the impregnation method are listed by listing the elements of the additive ingredients as it is for the convenience of marking the absorbents prepared, but the absorbent component is indicated by potassium carbonate as 'K' and potassium hydride as 'KOH'. (For example, in the case of Al) was listed as 'KAl', and the absorbent prepared by the physical mixing method was denoted as 'KAl-P' by adding '-P' at the end.

However, the following examples are only disclosed for the purpose of illustration and should not be construed as limited to the scope of the invention by the matter set forth in the examples, those skilled in the art to various modifications, changes, additions within the spirit and scope of the invention Etc. may be possible.

 Therefore, the conditions of the manufacturing method shown in the following examples, and the process conditions for performance test, such as the kind of support component used in the manufacture of the absorbent, the kind of absorbent component, sulfur dioxide removal temperature, firing temperature, firing conditions, It is apparent to those skilled in the art that the firing time can be appropriately selected within the range of conditions necessary to achieve the object of the present invention.

Preparation Example of Desulfurization Absorber

Example 1 Preparation of Potassium Carbonate Desulfurization Absorber by Impregnation (KAl)

This embodiment relates to a potassium-based absorbent prepared by the impregnation method using alumina as a support component and potassium carbonate as a sulfur dioxide absorption component.

The KAl desulfurization absorber of this embodiment is a first step of dissolving 2.505 g of potassium carbonate in 15 g of distilled water to prepare an aqueous solution, a second step of adding alumina 5.01 g as a support component to an aqueous potassium carbonate solution and stirring, and a vacuum rotary concentrator. The third step of impregnating potassium carbonate on the surface of alumina, the fourth step of firing the powder produced in the third step at 400 ° C. in a nitrogen atmosphere, and the size of the fired particles to 20 μm to 5 mm through sieve separation. Obtained in powder form through a fifth step of keeping constant.

Example 2 Preparation of Potassium Carbonate Desulfurization Absorber Using Impregnation Method (KTi)

This example relates to a potassium-based absorbent prepared by impregnation using titania as a support component and calcium carbonate as a sulfur dioxide absorption component, except that the support component is used in the same manner as in Example 1. An absorbent was prepared.

Example 3 Preparation of Potassium Carbonate Desulfurization Absorber Using Impregnation Method (KZr)

The present Example relates to a potassium-based absorbent prepared by impregnation using zirconia as a support component and potassium carbonate as a sulfur dioxide absorbing component, except that the support component is used in the same manner as in Example 1 except that zirconia is used. Was prepared.

Example 4 Preparation of Potassium Carbonate Desulfurization Absorber Using Impregnation Method (KMg)

The present embodiment relates to a potassium-based absorbent prepared by impregnation using magnesia as a support component and potassium carbonate as a sulfur dioxide absorbing component, except that the support component is used in the same manner as in Example 1 except that magnesia is used. Was prepared.

Example 5 Preparation of Potassium Carbonate Desulfurization Absorber Using Impregnation Method (KAC)

The present Example relates to a potassium-based absorbent prepared by impregnation method using activated carbon as a support component and potassium carbonate as a sulfur dioxide absorbing component, except that the support component is used in the same manner as in Example 1. An absorbent was prepared.

Example 6 Preparation of Potassium Carbonate Desulfurization Absorber Using Physical Mixing Method (KAl-P)

This embodiment is a potassium sorbent (KAl-P) prepared by physical mixing using alumina as a support component and potassium carbonate as a sulfur dioxide absorbing component.

The KAl-P desulfurization absorbent of the present embodiment is a first step of mixing 2.05 g of potassium carbonate powder with 15 g of alumina powder, a second step of adding and mixing an organic binder (ethylene glycol) to the first step powder to prepare a dough, The third step of preparing the mixture in the form of dough in pellet form through extrusion, the fourth step of baking the mixture in pellet form for 4 hours at 400 ℃, and finally the size of the calcined particles through a sieve separation 20㎛ ~ Obtained in powder form through a fifth step of keeping constant at 5 mm.

Example 7 Preparation of Potassium Hydroxide-Based Desulfurization Absorber Using Impregnation Method (KOHAl)

This example is a potassium-based absorbent prepared by the impregnation method using alumina as a support and potassium hydroxide as the sulfur dioxide absorption component.

The KOHAl desulfurization absorbent of this embodiment is prepared by dissolving 2.505 g of potassium carbonate in 15 g of distilled water to prepare an aqueous solution, using a vacuum rotary concentrator, and a second step of adding and stirring 5.01 g of alumina powder to an aqueous potassium carbonate solution. A third step of impregnating potassium carbonate on the surface of alumina, a fourth step of firing the powder produced in the third step at 400 ° C. in a nitrogen atmosphere, and finally, the size of the calcined particles is reduced to 20 μm to 5 mm through a sieve separation. Obtained in powder form through a fifth step of keeping constant.

Example of Desulfurization Performance of Desulfurization Absorber

Examples 8 and 9 show the desulfurization performance of the potassium carbonate-based desulfurization absorber and the potassium hydroxide-based desulfurization absorber, and Examples 10 and 11 show the sulfur dioxide removal ability according to the temperature and the water concentration of the desulfurization absorber. , Example 12 is an example showing the possibility of recycling the desulfurization absorbent.

Example 8 Desulfurization Performance of Potassium Carbonate Desulfurization Absorber

This Example is to determine the desulfurization performance for each of the potassium carbonate-based desulfurization absorbers prepared in Examples 1 to 5, the experiment and analysis conditions for the desulfurization performance evaluation are as follows. After filling 0.5 g of the absorbent prepared in each example into a fixed bed reactor having a diameter of 1 cm, air containing 11% by volume of water was absorbed using a moisture generating device using 5000 ppm sulfur dioxide and a vapor pressure of water. After passing through the packed reactor, the gas discharged from the reactor was analyzed by gas chromatography. The absorption capacity of the desulfurization absorber was calculated as a percentage ((SO ₂ g absorbed SO / g number of absorbent) × 100) the mass of sulfur dioxide absorbed per gram of the absorbent, the results are as follows, KAl, excluding the KZr absorber It was found that sulfur dioxide absorption of KMg, KAC, and KTi absorbents was very high.

Absorbent Type Absorption ability KAl Absorbent (Example 1) 30.4% KTi Absorbent (Example 2) 30% KMg Absorbent (Example 4) 30% KAC Absorbent (Example 5) 30% KZr Absorbent (Example 3) 10%

Example 9 Desulfurization Performance of Potassium Hydroxide-based Desulfurization Absorber

This example is to determine the desulfurization performance of the potassium hydroxide desulfurization absorber (KOHAl absorbent) prepared in Example 7, the potassium hydroxide desulfurizer (KOHAl absorbent) 0.5 prepared in Example 7 in a fixed bed reactor of diameter 1cm After the g was charged, the absorption capacity of the desulfurized absorbent after passing air containing 5000 ppm of sulfur dioxide and 11% by volume of moisture in the air through a reactor filled with an absorbent at an absorption temperature of 0 ° C. was measured. The sulfur dioxide absorption capacity of the KOHAl absorbent was calculated in the same manner as in Example 8, and was relatively high at 18%, but was found to be about 10% lower than that of the potassium carbonate absorbent. However, when the reaction temperature of the absorbent was 30 ℃ and the moisture content was changed to 9% by volume, the rest of the conditions were maintained as the experimental conditions described above, and the sulfur dioxide absorption rate was found to be slower than that of the potassium carbonate absorbent. Was high as 30.6%.

In potassium carbonate-based absorbents, carbon dioxide generates a certain amount of carbon dioxide when absorbing sulfur dioxide, but KOHAl absorbents do not contain carbonic acid at all, which does not generate carbon dioxide. It was confirmed through.

Therefore, considering that potassium hydroxide-based desulfurization absorbers are currently actively concerned about the reduction of carbon dioxide due to global warming and the movement of regulations, there is a need to cope with future restrictions on the use of potassium carbonate-based absorbents. Potassium-based desulfurization absorbers have a meaning.

Example 10 Desulfurization Performance of Potassium Carbonate Desulfurization Absorber with Temperature

This embodiment is to determine the desulfurization performance according to the temperature of the potassium carbonate-based desulfurization absorber (KAl absorbent) prepared in Example 1, the potassium carbonate-based desulfurization absorber (KAl) prepared in Example 1 in a fixed bed reactor of 1cm diameter Absorbent) After filling 0.5g, maintain the same condition using air containing 5000ppm sulfur dioxide and 9% by volume of water, and change the absorption temperature to 30 ℃, 50 ℃ and 60 ℃ respectively to improve the absorption ability of the desulfurized absorbent. Measured.

The sulfur dioxide absorption at each temperature was 31.2% at 30 ° C, 30.28% at 50 ° C, and 30.12% at 60 ° C. Therefore, it can be seen that sulfur dioxide absorption proceeds well from room temperature to 60 ° C. when the moisture content is kept constant.

Example 11 Desulfurization Performance of Desulfurization Absorber According to Water Content

This embodiment is to determine the desulfurization performance according to the water content of the potassium carbonate-based desulfurization absorber (KAl absorbent) prepared in Example 1, the potassium carbonate-based desulfurization absorber prepared in Example 1 in a fixed bed reactor of diameter 1cm ( KAl sorbent) and then filled with 5000 ppm sulfur dioxide and air containing 0% by volume, 5% by volume, 9% by volume, 12% by volume and 18% by volume of air at 50 ° C. The sulfur dioxide absorption capacity of the desulfurization absorbent after passing through was measured, and the result is shown by the graph of FIG.

Referring to FIG. 1, the sulfur dioxide removal capacity is only 7.2% when the water content is 0% by volume, 14.68% at 5% by volume, 22.68% at 9% by volume, 30.68% at 11% by volume, and 18% by volume. The percentage is 28.4%. Under the reaction temperature of 50 ℃, the moisture content increased from 0% to 11% by volume, and the sulfur dioxide absorption capacity was steadily increased.In the case of 18% by volume, the sulfur dioxide absorption was rather higher than that of 11% by volume. It tends to decrease slightly.

This means that 7.2% of sulfur dioxide can be absorbed even if there is no water, and if moisture is present, more sulfur dioxide can be removed. Means no increase in sulfur dioxide absorption.

In addition, the present embodiment was carried out at an extremely high concentration of sulfur dioxide of 5000 ppm, showing an absorption capacity of 34% or more of sulfur dioxide in an average of 5% by volume or more of moisture, and thus for the purpose of removing several tens to several ppm of sulfur dioxide. In this case, it is possible to sufficiently remove only the relative humidity conditions in the atmosphere, and even when the present absorbent is applied to the combustion flue gas generating process, sufficient moisture is present in the flue gas, and thus it is expected to be excellent in removing sulfur dioxide contained in the industrial flue gas.

Example 12 Recyclability of Waste Absorbents Absorbed with Sulfur Dioxide

This example is to determine whether the desulfurized absorber (KAl) prepared in Example 1 can be recycled for other purposes after the sulfur dioxide absorption is completed. After absorbing sulfur dioxide in the absorbent of Example 1, X-ray diffraction The component was identified using an (XRD) device. Fig. 2 shows the results of X-ray diffraction analysis of the KAl absorbent before sulfur dioxide absorption (indicated by (1) in FIG. 2) and after absorption (indicated by (2) in FIG. 2). From FIG. 2, the characteristic peak of potassium carbonate can be clearly identified based on the 2θ value in the KAl absorbent before sulfur dioxide absorption, and the characteristic peak of potassium sulfate, not the characteristic peak of potassium carbonate, appeared after sulfur dioxide absorption. Therefore, it can be confirmed that potassium carbonate, which is an absorbent component of the absorbent after sulfur dioxide absorption, was mostly converted to potassium sulfate.

Potassium sulfate can be blended with various fertilizers and the fertilizer effect is quickly known, so it is well known as a representative fertilizer component, and various uses such as manufacturing raw materials or pharmaceuticals of chemicals. Therefore, the separation and purification of potassium sulfate from the waste absorbent, which has completed sulfur dioxide absorption, can be used in various chemical industries. In addition, support components in the form of metal oxides (alumina, magnesia, zirconia, titania, activated carbon, etc.) can be recycled in the manufacture of absorbents and are very useful in other industries.

As described above, the potassium-based desulfurization absorber according to the present invention has a high sulfur dioxide removal ability even in a low temperature region, and is a simple absorbent and easy to handle compared to the wet method as a dry absorber. Widely available. In addition, high-quality potassium sulfate formed as a by-product of the waste absorbent can be separated and purified and used as a raw material and fertilizer of chemicals, making it possible to construct an ideal environment-friendly harmful gas removal system.

Claims (10)

Alkali metals as absorption components for absorbing sulfur dioxide; And A desulfurization absorber for removing sulfur dioxide containing a metal oxide as a support component in which the alkali metal is dispersed. The method of claim 1, The alkali metal desulfurization absorber for removing sulfur dioxide, characterized in that one or two or more selected from the group consisting of potassium carbonate, potassium hydroxide, potassium oxide, potassium hydrogencarbonate. The method of claim 1, The metal oxide is one or two or more combinations selected from the group consisting of alumina, titania, zirconia, magnesia, or desulfurization absorber for removing sulfur dioxide, characterized in that the activated carbon. The method according to any one of claims 1 to 3, Desulfurization absorbent for removing sulfur dioxide, characterized in that the content of the alkali-based metal as the absorbent component is 0.1 to 40% by weight of the total weight of the absorbent. The method according to any one of claims 1 to 3, Desulfurization absorber for removing sulfur dioxide, characterized in that the sulfur dioxide in the atmosphere can be removed at a temperature range of 10 ℃ to 150 ℃. The method according to any one of claims 1 to 3, Desulfurization absorber for removing sulfur dioxide, characterized in that the sulfur content in the atmosphere can be removed in the range of 0 to 18% by volume of moisture in the atmosphere. A first step of preparing an alkali metal precursor solution of 0.1 to 40% by weight of the total weight of the absorbent; Adding a metal oxide powder as a support component to the solution, followed by stirring to prepare a turbid solution; A third step of impregnating the turbid liquid with an alkali metal using a rotary vacuum concentrator; And A method for producing a desulfurized absorbent for removing sulfur dioxide comprising a fourth step of drying and then firing the absorbent powder formed after impregnation. A first step of mixing 0.1-40 wt% of the alkali metal powder of the support component and the metal oxide powder serving as the support component; A second step of adding and mixing an organic binder to the mixed powder; Method for producing a desulfurization absorber for removing sulfur dioxide comprising a third step of drying the mixture prepared in the second step and calcining. The method according to claim 7 or 8, The alkali-based metal is a method for producing a desulfurization absorber for removing sulfur dioxide, characterized in that one or two or more selected from the group consisting of potassium carbonate, potassium hydroxide, potassium oxide, potassium bicarbonate. The method according to claim 7 or 8, The metal oxide is one or a combination of two or more selected from the group consisting of alumina, titania, zirconia, magnesia, or a method for producing a desulfurization absorber for removing sulfur dioxide, characterized in that the activated carbon.

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