KR101210929B1 - Carbon dioxide absorbent and method of removal of carbon dioxide from landfill gas by the simultaneous generation of barium carbonate using the same - Google Patents

Abstract

The present invention relates to a novel carbon dioxide absorbent and a method for removing carbon dioxide through simultaneous production of barium carbonate from landfill gas (LFG) using the same, and an alkanolamine, alkyl as a carbon dioxide absorbent that separates and absorbs carbon dioxide from landfill gas. It is characterized by consisting of a mixed aqueous solution of amine or ammonia and barium chloride, characterized in that to remove carbon dioxide while generating barium carbonate from landfill gas using this.
According to the present invention, by using a mixed aqueous solution absorber in which barium chloride is added to an aqueous solution of an amine-based and ammonia absorbent, which is a conventional carbon dioxide absorbent, barium carbonate can be produced from a large amount of carbon dioxide in a landfill gas in a variety of industrial uses. The landfill gas may be purified by removing carbon dioxide from the landfill gas.

Description

Carbon dioxide absorbent and method of removal of carbon dioxide from landfill gas by the simultaneous generation of barium carbonate using the same}

The present invention relates to a method for removing carbon dioxide through simultaneous production of barium carbonate from landfill gas using a carbon dioxide absorbent, and more particularly, using a carbon dioxide absorbent composed of an alkanolamine, an alkylamine or a mixed aqueous solution of ammonia and barium chloride. To produce barium carbonate from landfill gas and simultaneously remove carbon dioxide from landfill gas.

Landfill gas (LFG) contains methane gas, carbon dioxide and nitrogen and hydrogen in small amounts as the main components, and methane in landfill gas can be collected and used as alternative energy, and global warming due to the increase of carbon dioxide in the atmosphere Has become an important environmental problem to be solved. As such, it is necessary to develop a technology of separating and removing carbon dioxide from landfill gas to obtain purified methane and using it for alternative energy, and to remove carbon dioxide to solve environmental problems.

Techniques for separating and removing carbon dioxide from landfill gas include physical absorption and chemical absorption absorption, adsorption, deep cooling, and membrane separation. As a technique commercialized in the absorption method, there is a wet amine method. The wet amine method has a feature of reducing deterioration to oxygen and increasing carbon dioxide absorption ability by using a mixed solution of alkanolamine and a corrosion inhibitor as an absorbent, and a number of wet absorption methods using amines as an absorbent have been commercialized.

The wet absorption process using such amines has a problem in that a high temperature is required for high carbon dioxide recovery efficiency and a large amount of energy is required, resulting in a high process operation cost.

Meanwhile, in the already developed carbon dioxide separation technology, the adsorption method is a method of separating carbon dioxide using a solid adsorbent such as zeolite and activated carbon that selectively adsorbs carbon dioxide. When the adsorption is large and at atmospheric pressure, there is a problem in that the productivity is low due to low productivity, and the consumption of power costs due to low pressure desorption has a big problem.

Therefore, in order to improve the carbon dioxide absorption performance, a mixed absorbent in which various additive compounds, chloride, nitrate, and sulfate compounds are added to a carbon dioxide absorbent solution has been developed.

In addition, barium carbonate is a material used for the production of barium titanate for ceramic capacitors, optical glasses, pigments, and the like, and has various industrial applications. A technique for removing carbon dioxide from landfill gas by a carbon dioxide absorbent while simultaneously generating barium carbonate with various industrial uses from carbon dioxide, which has a large amount of landfill gas by a carbon dioxide absorbent added with barium chloride, has not been reported.

Therefore, the first problem to be solved by the present invention is to provide a carbon dioxide absorbent comprising barium chloride as a carbon dioxide absorbent to separate and absorb carbon dioxide from the landfill gas.

The second problem to be solved by the present invention is to provide a method for removing carbon dioxide while simultaneously generating barium carbonate from the landfill gas using the carbon dioxide absorbent.

The present invention to achieve the first object,

An absorbent for separating and absorbing carbon dioxide from landfill gas (LFG), the absorbent comprising a mixed aqueous solution of alkanolamine or alkylamine and barium chloride, and a mixed aqueous solution of ammonia and barium chloride. It provides a carbon dioxide absorbent, characterized in that.

According to an embodiment of the present invention, the alkanolamine or alkylamine is monoethanolamine (MEA), diethanolamine (DEA), diethylenetriamine (DETA), triethanolamine (TEA), N-methyldiethanol Amine (MDEA), 2-amino-2-methyl-1-propanol (AMP) or mixtures thereof.

According to another embodiment of the present invention, the alkanolamine or alkylamine may be 1 to 30% by weight based on the weight of the mixed aqueous solution, and the barium chloride may have a concentration of 0.1 to 0.5 M.

According to another embodiment of the present invention, the ammonia may be 2 to 5% by weight relative to the weight of the mixed aqueous solution, and the barium chloride may have a concentration of 0.1 to 0.5 M.

According to another aspect of the present invention,

Reacting the carbon dioxide absorbent with landfill gas (LFG) to separate and absorb carbon dioxide, and reacting the separated and absorbed carbon dioxide with barium chloride of the absorbent to produce barium carbonate. It provides a method for removing carbon dioxide through the simultaneous production of barium.

According to an embodiment of the present extinction, the carbon dioxide absorption amount of the carbon dioxide absorbent is 0.35 ~ 1.95 CO ₂ mol / L (absorbent).

According to another embodiment of the present invention, the amount of barium carbonate produced may be 34 to 38 g / L (absorbent).

According to the present invention, a mixed aqueous solution in which barium chloride is added to an aqueous amine-based and ammonia-absorbent aqueous solution of a conventional carbon dioxide absorbent is used as a carbon dioxide absorbent. At the same time, carbon dioxide can be removed from the landfill gas to purify the landfill gas to use methane gas as an alternative energy.

FIG. 1 is an electron scanning microscope photograph showing crystals of barium carbonate produced by a reaction of an aqueous solution absorbent of alkanolamine or an alkylamine with barium chloride and carbon dioxide according to an embodiment of the present invention.
FIG. 2 is an electron scanning micrograph showing crystals of barium carbonate produced by a reaction of a mixed aqueous solution absorber of ammonia and barium chloride and carbon dioxide according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for purifying landfill gas by simultaneously removing carbon dioxide from landfill gas and generating barium carbonate, and using a conventional amine-based absorbent and a carbon dioxide absorbent having barium chloride added to ammonia.

According to an embodiment of the present invention, in the absorbent to separate and absorb carbon dioxide from landfill gas (LFG), the absorbent comprising an alkanolamine or a mixed aqueous solution of alkylamine and barium chloride, ammonia and barium chloride It is characterized in that it is an absorbent containing a mixed aqueous solution of.

According to a preferred embodiment of the present invention, the alkanolamine is monoethanolamine (MEA), diethanolamine (DEA), diethylenetriamine (DETA), triethanolamine (TEA), N-methyl diethanolamine ( MDEA), 2-amino-2-methyl-1-propanol (AMP) or mixtures thereof, and preferably include monoethanolamine (MEA) having good solubility in water and excellent reaction rate at room temperature. It may be a mixture.

According to a preferred embodiment of the present invention, the alkanolamine or alkylamine may be 1 to 30% by weight relative to the weight of the mixed aqueous solution absorbent, and the barium chloride may have a concentration of 0.1 to 0.5 M.

According to a preferred embodiment of the present invention, the ammonia may be 2 to 5% by weight based on the weight of the mixed aqueous solution, the barium chloride may have a concentration of 0.1 to 0.5 M.

The present invention reacts with landfill gas (LFG) using a carbon dioxide mixed aqueous solution absorbent including barium chloride to separate and absorb carbon dioxide, and the absorbed carbon dioxide reacts with barium chloride of the absorbent to produce barium carbonate. By removing the carbon dioxide through the simultaneous production of barium carbonate to the landfill gas rotor.

Separation and absorption of carbon dioxide from the landfill gas according to the present invention, and at the same time a process for generating barium carbonate is characterized in that the pressurized energy is performed at room temperature without requiring.

Mechanism for the alkanolamine to react with the carbon dioxide of the landfill gas is as follows.

_{R-NH 2 (l) +} H 2 O (l) ↔ R-NH 3 + (aq) + OH - (aq) (1)

CO ₂ (g) ↔ CO ₂ (aq) (2)

^{_{CO 2 (aq) + OH -}} ↔ HCO 3 - (aq) (3)

^{_{HCO 3 - (aq) + OH}} - (aq) ↔ CO 3 2 - (aq) + H 2 O (l) (4)

The mechanism by which the ammonia reacts with the carbon dioxide of the landfill gas is as follows.

_{NH 3 + CO 2 + H 2} O ↔ NH 4 + + HCO 3 - (5)

^{_{NH 3 + HCO 3 - ↔ NH}} 2 CO 2 - + H 2 O (6)

^{_{NH 3 + HCO 3 - ↔ CO}} 3 2 - + 2NH 4 + (7)

In addition, the production mechanism of barium carbonate is as follows.

Ba ^{2 +} + 2HCO ^{3 -} ↔ CO ₂ + BaCO ₃ + H ₂ O (8)

Ba ^{2 +} + CO ₃ ^{2 -} ↔ BaCO ₃ (9)

According to a preferred embodiment of the present invention, the carbon dioxide absorbent of the alkanolamine or alkylamine and barium chloride mixed aqueous solution, the mixed aqueous solution of ammonia and barium chloride, carbon dioxide absorption amount of alkanolamine or alkylamine, weight percent of ammonia, 0.35 to 1.95 CO ₂ depending on the concentration of barium chloride mol / L (absorbent).

According to another preferred embodiment of the present invention, the amount of barium carbonate produced at the same time while removing carbon dioxide according to the present invention may be 34 to 38 g / L (absorbent).

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. It will be apparent to those skilled in the art, however, that these examples are provided to further illustrate the present invention, and the scope of the present invention is not limited thereto.

EXAMPLES Preparation of Aqueous Carbon Dioxide Absorbent Solution According to the Present Invention.

Example 1

A mixed aqueous solution absorber was prepared such that monoethanolamine and barium chloride were 5 wt% and 0.2 M, respectively.

Example 2

A mixed aqueous solution absorbent was prepared such that diethanolamine and barium chloride were 5 wt% and 0.2 M, respectively.

Example 3

A mixed aqueous solution absorber was prepared such that diethylenetriamine and barium chloride were 5 wt% and 0.2 M, respectively.

Example 4

A 25 wt% ammonia standard solution was diluted in deionized water to prepare a 2 wt% aqueous ammonia solution, and 50 g of barium chloride was dissolved to prepare a 1 L mixed solution absorbent.

Example 5

A 25 wt% ammonia standard solution was diluted in deionized water to prepare a 5 wt% ammonia solution, and 50 g of barium chloride was dissolved to prepare 1 L of a mixed solution absorbent.

<Comparative Example>

Comparative Example 1

Unlike Example 1, an absorbent aqueous solution containing 5% by weight of monoethanolamine was prepared without adding barium chloride.

Comparative Example 2

Unlike Example 2, an aqueous absorbent solution containing 5% by weight of diethanolamine was prepared without adding barium chloride.

Comparative Example 3

Unlike Example 3, an aqueous absorbent solution containing 5% by weight of diethylenetriamine was prepared without adding barium chloride.

<Experimental Example>

Experimental Example 1. Measurement of carbon dioxide unit absorption and barium carbonate production

The landfill gas obtained from the Seoul metropolitan landfill was flowed into the absorbent in the reactor at a flow rate of 1.5 l / min using a mass flow controller (MFC). At this time, in order to remove gaseous impurities in the landfill gas, the landfill gas was passed through activated carbon and a saturator located in front of the reactor. The landfill gas was flowed through the CERAMIC BUBBLE SPARGER in the absorber of the reactor, and the pH was measured using an pH analyzer (Orion 420 A +) mounted on the reactor during the absorption reaction. The carbon dioxide concentration was measured and recorded automatically in real time. In the front of the infrared analyzer, all the moisture introduced into the analyzer was removed by using a silica gel dust collector, and the coolant at the top of the reactor was used to prevent the change of the absorbent concentration during the absorption reaction. The absorbent dose used in the experiment was 1 L and in most cases the absorption reaction was completed within 50 minutes. The reaction temperature was maintained at room temperature (about 20 ° C.) for both the reactor and the water saturator.

The maximum carbon dioxide absorption was calculated using the difference between the carbon dioxide concentration (about 45%) in the landfill gas injected into the absorbent, the carbon dioxide concentration in the gas discharged to the rear end of the reactor after the absorption reaction, and the landfill gas flow rate introduced. Barium carbonate production was calculated using the standard method 2540 B.

division Carbon dioxide absorbent Max CO2 Absorption
(mol / [sorbent]) Example 1 5% by weight MEA + 0.2M BaCl ₂ -2H ₂ O 0.64 Example 2 5% by weight DEA + 0.2M BaCl ₂ -2H ₂ O 0.4 Example 3 5 wt% DETA + 0.2 M BaCl ₂ H ₂ O 0.76 Example 4 2% by weight ammonia + (50 g) BaCl ₂ -2H ₂ O 0.72 Example 5 5% by weight ammonia + (50 g) BaCl ₂ -2H ₂ O 1.86 Comparative Example 1 5% by weight MEA 0.62 Comparative Example 2 5 wt% DEA 0.45 Comparative Example 3 5 wt% DETA 0.84

division Carbon dioxide absorbent Barium Carbonate Production
(g / [sorbent]) Example 1 5% by weight MEA + 0.2M BaCl ₂ -2H ₂ O 34.00 Example 2 5% by weight DEA + 0.2M BaCl ₂ -2H ₂ O 35.90 Example 3 5 wt% DETA + 0.2 M BaCl ₂ H ₂ O 37.80 Example 4 2% by weight ammonia + (50 g) BaCl ₂ -2H ₂ O 37.18 Example 5 5% by weight ammonia + (50 g) BaCl ₂ -2H ₂ O 37.14

As can be seen from the results of the above Examples, Comparative Examples, Experimental Examples, Tables 1 and 2, a conventional monoethanolamine (MEA) aqueous solution was used, rather than the amount of carbon dioxide absorbed when reacting with carbon dioxide at the same carbon dioxide partial pressure and reaction temperature. It can be seen that the carbon dioxide absorption performance was improved when barium chloride was added to the monoethanolamine (MEA) aqueous solution of Example 1 according to the present invention. However, in the case of the mixed absorbent aqueous solution in which barium chloride was added to the DEA and DETA aqueous solutions, the maximum amount of carbon dioxide absorbed was slightly reduced.

However, by using the carbon dioxide absorbent aqueous solution of Examples 1 to 5, which is an embodiment of the present invention, carbon dioxide is separated and absorbed from landfill gas, and at the same time, barium carbonate having excellent industrial utilization of 34 to 38 g / L based on the carbon dioxide absorbent is You can see that it is created.

&Lt; Evaluation example &

Evaluation Example 1 Electron Scanning Microscopy of Barium Carbonate Produced According to the Present Invention

Barium carbonate for electron scanning microscope was prepared using the drying method of the standard method 2540 B barium carbonate obtained after the end of the absorption reaction, and analyzed by using an electron scanning microscope (JEOL, J-5600).

1 is an electron scanning microscope photograph showing crystals of barium carbonate produced from a reaction of a mixture solution of an alkanolamine or alkylamine and barium chloride with carbon dioxide, and FIG. 2 is ammonia and barium chloride according to an embodiment of the present invention. Is a scanning electron micrograph showing the crystal of barium carbonate produced by the reaction of a mixed aqueous solution absorbent and carbon dioxide.

As shown in Figures 1 and 2 it can be confirmed the physical properties of the barium carbonate produced according to the present invention. It can be seen that the barium carbonate produced using the absorbent containing alkanolamine or alkylamine than the absorbent including ammonia has a finer powder form.

Claims (7)

An absorbent for separating and absorbing carbon dioxide from landfill gas (LFG), the carbon dioxide absorbent comprising an aqueous solution of alkanolamine or alkylamine and barium chloride. In an absorbent for separating and absorbing carbon dioxide from landfill gas (LFG), it comprises a mixed aqueous solution of ammonia and barium chloride, the ammonia is contained in 2 to 5% by weight relative to the weight of the mixed aqueous solution, the barium chloride is Carbon dioxide absorbent, characterized in that the concentration is 0.1 ~ 0.5M. The method of claim 1,
The alkanolamines or alkylamines are monoethanolamine (MEA), diethanolamine (DEA), diethylenetriamine (DETA), triethanolamine (TEA), N-methyldiethanolamine (MDEA), 2-amino- 2-methyl-1-propanol (AMP) or a mixture thereof, characterized in that contained in 1 to 30% by weight relative to the weight of the mixed aqueous solution, the barium chloride is characterized in that the carbon dioxide, characterized in that the concentration is 0.1 ~ 0.5 M Absorbent. delete (A) reacting the carbon dioxide absorbent according to claim 1 or 2 with landfill gas (LFG) to separately absorb carbon dioxide; And
(B) reacting the separated and absorbed carbon dioxide and the barium chloride of the absorbent to produce barium carbonate; and carbon dioxide removal method through the simultaneous production of barium carbonate containing the landfill gas. The method of claim 5, wherein
The carbon dioxide absorption amount of the carbon dioxide absorbent is 0.35 ~ 1.95 CO ₂ Method of removing carbon dioxide through the simultaneous production of barium carbonate, characterized in that the mol / L (absorbent). The method of claim 5, wherein
The amount of barium carbonate generated is 34 ~ 38 g / L (absorbent), characterized in that carbon dioxide removal method through the simultaneous production of barium carbonate landfill gas rotor.

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