KR20140031692A - Method for absorbing carbon dioxide and synthesis of alkali metal ethyl carbonate via the same and method for generation of ethanol - Google Patents

Abstract

The present invention provides a method for wet absorption of carbon dioxide, comprising the step of acquiring an alkali metal ethyl carbonate via the wet absorption of carbon dioxide injected after dissolving an alkali metal hydroxide in ethanol. According to the present invention, the final product of a carbonate after the absorption of carbon dioxide is easy to separate despite using an alkali metal as a raw material because the carbonate is precipitated in a solid state. The present invention can solve the problems of an existing wet absorption technology based on an aqueous solution using an alkali metal from the technical aspect of CSS. Also, the present invention can regenerate or manufacture ethanol easily because the alkali metal ethyl carbonate in a solid state is changed into ethanol in a liquid state and MeHCO3 in a solid state by reacting with water.

Description

Method for absorbing carbon dioxide and Synthesis of alkali metal ethyl carbonate via the Same and Method for generation of ethanol}

The present invention is a method of wet absorption of carbon dioxide generated by the use of fossil fuel in the industry, such as a thermal power plant and discharged to the atmosphere, a method for producing alkali metal ethyl carbonate using the same method and sodium ethyl carbonate, potassium ethyl It relates to a carbonate and a method for producing ethanol using the same.

Carbon dioxide is one of the greenhouse gases and is known to have the most serious impact on global warming due to the release of air from increased use of fossil fuels. In particular, since large amounts of carbon dioxide are generated in large-scale combustion facilities such as thermal power plants, steel mills, petrochemicals, and cement industries, if the carbon dioxide emissions are not controlled, global environmental disasters may occur due to global warming.

Therefore, only the CO ₂ separated from the exhaust gas, trapped by storing CO ₂ capture and storage (Carbon Capture &Sequestration; CCS) that in order to reduce the CO ₂ emitted into the atmosphere has been actively developed technology research.

The basic concept of carbon dioxide capture and storage technology is a general term for sequestration or storage, which is a method of capturing generated carbon dioxide and treating it without releasing it into the atmosphere. Generally, carbon capture and Storage).

CCS will be one of a series of ways to stabilize greenhouse gas concentrations while continuing to use fossil fuels. CO2 storage and storage technology has the potential to increase total variability in reducing total cost of emissions and achieving GHG emissions reduction.

CO2 capture technology can be classified into three types: post-combustion, pre-combustion, and oxyfuel combustion. Methods of recovering carbon dioxide after combustion include wet scrubbing, dry scrubbing, adsorption, membrane separation, and deep cooling.

Commercialization technologies to date are still costly and energy consuming to recover or separate CO ₂ from large-capacity flue gases, requiring technological innovation. The most common method of separating carbon dioxide is selective absorption, which often involves the reversible chemical reaction of carbon dioxide with chemicals in the absorbent.

Therefore, an object of the present invention is to economically separate and recover carbon dioxide generated from large-scale combustion facilities such as thermal power plants, steel mills, petrochemicals, cement industry, etc. to suppress the emission of CO ₂ into the atmosphere and ultimately solve environmental problems such as global warming. The present invention provides a carbon dioxide wet absorption method that is suitable for mass CO ₂ recovery technology and is economical and low in energy consumption.

In order to achieve the above object, the present invention provides a wet absorption method of carbon dioxide comprising the step of obtaining an alkali metal ethyl carbonate by dissolving the alkali metal hydroxide in ethanol and then wet absorption by injecting carbon dioxide.

In another aspect, the present invention provides a method for producing ethanol comprising the step of dissolving the solid alkali metal ethyl carbonate obtained by the above method in water to obtain ethanol.

In addition, the present invention comprises the steps of obtaining a mixed solution in which sodium hydroxide was dissolved in ethanol; And CO _2, CO ₂ -N ₂ gas mixture, CO ₂ -N ₂ on the resulting mixed solution Sodium ethyl carbonate (hereinafter abbreviated as 'SEC') or potassium ethyl carbonate (hereinafter, abbreviated as 'PEC') by wet absorption by mixing gas or CO ₂ -He mixed gas. It provides a method for producing sodium ethyl carbonate or potassium ethyl carbonate comprising the step of obtaining.

The wet absorption method of carbon dioxide according to the present invention is a process of capturing, storing and using CO ₂ by synthesizing SEC or PEC as a solid by absorbing CO ₂ in a C ₂ H ₅ OH solution in which NaOH or KOH, which is an alkali metal hydroxide, is dissolved. It is eco-friendly because the manufacturing process is simple, no organic substances harmful to the environment are used and ethanol can be recovered.

1 is an XRD analysis result of the precipitate produced after dissolving the solid (SEC) produced in the carbon dioxide absorption process in the embodiment of the present invention and the standard XRD data of sodium bicarbonate.

Unless defined otherwise, all technical terms used in the present invention have the following definitions and are consistent with the meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Also, preferred methods or samples are described in this specification, but similar or equivalent ones are also included in the scope of the present invention. The contents of all publications referred to herein are incorporated herein by reference.

The term " about " is used herein to refer to a reference quantity, a level, a value, a number, a frequency, a percent, a dimension, a size, a quantity, a weight, or a length of 30, 25, 20, 25, 10, 9, 8, 7, Level, value, number, frequency, percent, dimension, size, quantity, weight or length of a variable, such as 4, 3, 2 or 1%.

Throughout this specification, the terms “comprises” and “comprising”, unless otherwise indicated in the context, include a given step or component, or group of steps or components, but any other step or component, or It is to be understood that it does not exclude a step or group of components.

Hereinafter, the present invention will be described in detail.

Wet absorption method of carbon dioxide

The present invention provides a wet absorption method of carbon dioxide, which is a technique for producing a solid alkali metal ethyl carbonate by absorbing or trapping (storing, using) carbon dioxide in an ethanol solution in which alkali metal hydroxide is dissolved.

Specifically, as shown in Scheme 1, the step of obtaining alkali metal ethyl carbonate by dissolving the alkali metal hydroxide in ethanol (C ₂ H ₅ OH) and then wet absorption by injecting carbon dioxide.

C ₂ H ₅ OH + MeOH + CO ₂ → C ₂ H ₅ OCOOMe + H ₂ O (1)

In the above formula, Me is an alkali metal, and the alkali metal may include, for example, Li, Na, K, Rb, or Cs, and is most economical, especially when sodium and potassium are used. In other words, it is preferable to use sodium hydroxide or potassium hydroxide as the alkali metal hydroxide.

Conventional wet metal absorption techniques of CO ₂ using alkali metal hydroxides or alkaline earth metal oxides and hydroxides are well known throughout the long history. Alkaline earth metal oxides, hydroxides, while the solubility in water decreases required a large amount of water, by reaction with CO ₂ is precipitated with most alkaline earth metal carbonate it has the advantage of fixing the CO _2. Alkali metal hydroxides are mostly converted to bicarbonate form, so the amount of water and hydroxide needed to absorb the same amount of CO ₂ is small, but the solubility of the resulting carbonate and bicarbonate in water is so high that it is separated into solid form. CO ₂ is difficult to immobilize However, in the present invention, even if the alkali metal as a raw material, the resulting carbonate after CO ₂ absorption is easily precipitated in a solid form and separated.

That is, in the present invention, and with ethanol (C ₂ H ₅ OH) and the solvent rather than CO ₂ wet absorption process using the conventional alkali metal hydroxide aqueous solution of CO ₂ It is a technique of obtaining a carbonate in a solid form through wet absorption, and can solve the problems of the conventional aqueous solution-based wet absorption technology using alkali metal from the CCS technical aspect.

In one preferred example, the alkali metal may be sodium or potassium and the reaction is as shown in the following formulas 1-1 and 1-2.

C ₂ H ₅ OH + NaOH + CO ₂ → C ₂ H ₅ OCOONa + H ₂ O (1-1) or

C ₂ H ₅ OH + KOH + CO ₂ → C ₂ H ₅ OCOOK + H ₂ O (1-2)

That is, the present invention absorbs and collects CO ₂ in the process of producing sodium ethyl carbonate (SEC) or potassium ethyl carbonate (PEC) as a solid product. Thus, the SEC or PEC synthesis process can reduce the CO ₂ emissions to air and can be used as a wet absorption method of CCS technology.

2. Sodium (or Potassium) Ethyl Carbonate  And preparation method thereof

The present invention also provides a method for preparing sodium ethyl carbonate or potassium ethyl carbonate through wet absorption of CO ₂ and sodium ethyl carbonate (SEC) or potassium ethyl carbonate (PEC) prepared according to the method. According to the previous studies, there have been studies on the preparation of SEC and PEC, but only the theoretical synthesis thereof has been presented. In fact, the results of synthesizing and verifying and analyzing the SEC and PEC cannot be found.

Accordingly, the present invention synthesizes SEC or PEC through CO ₂ absorption, proves that the material is SEC and PEC, and includes the results of analysis and use of the properties of the material.

The method for preparing sodium ethyl carbonate (SEC) or potassium ethyl carbonate (PEC) according to the present invention comprises the following steps.

1) obtaining a mixed solution of 0.05 ~ 3.5M concentration dissolved sodium hydroxide or potassium hydroxide in ethanol; And

2) CO ₂ , CO ₂ -N ₂ mixed gas, CO ₂ -N ₂ Obtaining sodium ethyl carbonate or potassium ethyl carbonate by wet absorption by injecting a mixed gas or a CO ₂ -He mixed gas;

That is, using ethanol (C ₂ H ₅ OH) as a solvent and dissolving NaOH or KOH which is an alkali metal hydroxide therein to prepare a solution of 0.05 ~ 3.5M concentration, CO ₂ or CO ₂ -N ₂ mixed gas Is injected into the solution to chemically absorb and react with CO ₂ to produce SEC or PEC. During injection, a gas may be uniformly injected into the solution by using a sparger made of fiberglass to facilitate the reaction. After the injection, confirm the end of the reaction by measuring the CO ₂ concentration of the discharged gas. Next, SEC or PEC, which is a solid produced by filtering the solution, is separated and dried to finally complete SEC or PEC manufacturing. The drying may be performed at 50 ° C. in a vacuum state for 3 hours or more using a vacuum oven. When dissolving the SEC or PEC solids generated as required in distilled water comprises the step of producing or reproducing, recovering the C ₂ H ₅ OH, and wherein, using sodium hydroxide, the generation NaHCO ₃ with C ₂ H ₅ OH When potassium hydroxide is used, KHCO ₃ is generated together with C ₂ H ₅ OH.

Ethanol Manufacturing Method

The present invention also provides a method for producing or recovering ethanol using the synthesized SEC or PEC.

Ethanol (C ₂ H ₅ OH) is used throughout the industry for a variety of applications such as alcohol, solvents, disinfectants, fuels, etc. Especially in the case of bio C ₂ H ₅ OH produced through fermentation, an alternative energy source for fossil fuels It is attracting attention, and much research is being conducted on this. Since ethanol is in a liquid phase at room temperature and atmospheric conditions, it is easier to store and transport than a gaseous substance, but if it is stored and transported and processed in a solid phase, it is easy to use and economical in all industries using C ₂ H ₅ OH. It can work quite advantageously in terms of aspect.

In the present invention, the aqueous solution of ethanol (C ₂ H ₅ OH) at a specific concentration can be prepared by dissolving water in the dried SEC or PEC solids. The aqueous solution contains a certain amount of NaHCO ₃ Or KHCO ₃ is included, and NaHCO ₃ or KHCO ₃ above the solubility is precipitated.

NaHCO ₃ produced by dissolving SEC or PEC in distilled water according to the present invention Or KHCO ₃ precipitation and the reaction in the C ₂ H ₅ OH regeneration step are shown in the following scheme (2).

C ₂ H ₅ OCOOMe + H ₂ O → C ₂ H ₅ OH + MeHCO ₃ (2)

Wherein Me is an alkali metal, preferably potassium or sodium. Thus, in one preferred example, the alkali metal ethyl carbonate may be sodium ethyl carbonate or potassium ethyl carbonate.

In the present invention, the liquid ethanol and solid NaHCO ₃ by reacting SEC or PEC in the solid form with water Or KHCO ₃ , so that ethanol can be regenerated or prepared by an easy method. That is, by storing the ethanol (C ₂ H ₅ OH) through the synthesized solid material SEC or PEC, it is possible to increase the efficiency with respect to the existing ethanol transport and use across all industries using ethanol. In addition, there is an advantage that the ethanol (C ₂ H ₅ OH) in the liquid state can be obtained at a desired concentration by controlling the amount of the alkali metal ethyl carbonate or water.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples are only the preferred embodiments of the present invention, and the present invention is not limited by the following Examples.

< Example  1>

SEC Manufacturing

C ₂ H ₅ OH and NaOH are mixed to prepare a solution of (0.05 ~ 3.5M) concentration. Then, in the absorption step, CO ₂ gas is injected into the solution to react the CO ₂ with the solution. In the injection, the gas is uniformly injected into the solution using an injector made of glass fiber. After injection, after confirming the completion of the reaction by measuring the CO ₂ concentration of the discharged gas, the solution is filtered to separate the solids, and then dried in a vacuum oven at 50 ℃ for 3 hours or more to complete SEC manufacturing do.

< Example  2>

PEC Manufacturing

A PEC was prepared in the same manner as in Example 1 except that KOH was used instead of NaOH.

< Experimental Example  1>

In this experiment, three analyzes were conducted to confirm that the product produced in the CO ₂ absorption step was SEC. First, the mass% of C and H were analyzed by Elemental Analyzer (EA) and Na mass% in SEC by ICE-AES. Second, a certain amount of SEC prepared was dissolved in water, and qualitatively analyzed the mass of C ₂ H ₅ OH and finally precipitated material. Component analysis of solids produced by CO ₂ absorption using EA and ICP-AES was performed, and the results of C ₂ H ₅ OH mass % analysis in the liquid solution in which the solids were dissolved using GC were obtained. 2 is shown.

The second column of Table 1 shows the theoretical mass ratios of carbon, hydrogen, oxygen, and Na atoms of the C ₂ H ₅ OCOONa material, SEC, and the third column contains the four atoms that make up the material synthesized in this experiment. The mass ratio is shown and the two values are almost identical.

Elements SEC theoretical mass percentage (%) % Produced Solids Mass C 32.15 32.20 H 4.50 4.42 O 42.83 42.00 (balance) Na 20.52 21.38

In Table 1, the solid synthesized by the above-described method was first confirmed to be SEC. Also, to dissolve the solid in distilled water to show that it is possible to prepare or recover ethanol (C ₂ H ₅ OH) according to Scheme (2) (2 The stoichiometric value based on the equation is calculated, and 4 g of the solid is dissolved in 31.86 g of distilled water.

ingredient Stoichiometric ethanol mass% Ethanol mass% measured C ₂ H ₅ OH 5.00 5.05

As a result, because it matches the expected value matches the mass ratio of about 5% of the C ₂ H ₅ After a OH value obtained was analyzed by the same time XRD a white solid material precipitated which, NaHCO ₃ standard, as shown in Fig. 1 C ₂ H ₅ The material precipitated simultaneously with OH was identified as NaHCO ₃ . Therefore, the solid material produced through CO ₂ absorption was identified as SEC, and also proved that C ₂ H ₅ OH production or recovery is possible by dissolving this material in distilled water.

< Experimental Example  2>

In addition, the present inventors obtained a result of dissolving PEC (potassium ethyl carbonate) obtained by using KOH instead of NaOH in water in the above experiment to recover ethanol, as shown in Table 3 below, that is, 4 g of PEC was 13.5 g of distilled water. When dissolved in, the ethanol concentration of 10.68% was confirmed, and this result was almost the same as the theoretical concentration of 10wt% of ethanol. Therefore, the results indicate that the present invention may use KOH instead of NaOH for the recovery or production of ethanol.

ingredient Stoichiometric ethanol mass% Ethanol mass% measured C ₂ H ₅ OH 10.00 10.68

So far I looked at the center of the preferred embodiment for the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (11)

As in the following Scheme 1, dissolving the alkali metal hydroxide in ethanol and injecting carbon dioxide to wet absorbing to obtain an alkali metal ethyl carbonate; comprising, wet absorption method of carbon dioxide.
C ₂ H ₅ OH + MeOH + CO ₂ → C ₂ H ₅ OCOOMe + H ₂ O (1)
(Wherein Me is an alkali metal) The method of claim 1,
The alkali metal hydroxide is sodium hydroxide (NaOH) or potassium hydroxide (KOH), characterized in that the wet absorption method of carbon dioxide. The method of claim 1,
The carbon dioxide is a carbon dioxide gas or carbon dioxide mixed gas, characterized in that the wet absorption method of carbon dioxide. Obtaining a mixed solution of 0.05 to 3.5 M concentration in which sodium hydroxide or potassium hydroxide is dissolved in ethanol; And
CO ₂ , CO ₂ -N ₂ mixed gas, CO ₂ -N ₂ to the obtained mixed solution Sodium ethyl carbonate or potassium ethyl carbonate, comprising obtaining sodium ethyl carbonate (SEC) or potassium ethyl carbonate (PEC) by wet absorption by injecting a mixed gas or CO ₂ -He mixed gas; Manufacturing method. 5. The method of claim 4,
And separating and vacuum drying the obtained sodium ethyl carbonate or potassium ethyl carbonate. Sodium ethyl carbonate prepared by the process according to claim 4. Potassium ethyl carbonate prepared by the process according to claim 4. A method for preparing an ethanol, comprising the following steps: dissolving a solid alkali metal ethyl carbonate prepared by the method according to claim 1 in water to obtain ethanol.
C ₂ H ₅ OCOOMe + H ₂ O → C ₂ H ₅ OH + MeHCO ₃ (2)
(Wherein Me is an alkali metal) 9. The method of claim 8,
Wherein the alkali metal ethyl carbonate is sodium ethyl carbonate or potassium ethyl carbonate. 9. The method of claim 8,
Characterized in that the yield of ethanol is controlled by controlling the amount of said alkali metal ethyl carbonate or water. 9. The method of claim 8,
Wherein the ethanol is used in the production of a mainstream or a fuel.

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