WO2016076675A1 - Absorbent composition, containing 2-amino 2-methyl 1-propanol (amp), for removing acid gases, and method for removing acid gases using same - Google Patents

Abstract

The present invention relates to an absorbent composition, containing AMP, for removing acid gases, and a method for removing acid gases using the same. The present invention is directed to a liquid absorbent prepared by mixing 2-diethylaminoethanol, 2-amino 2-methyl 1-propanol (AMP), water, and piperazine, and can efficiently remove CO₂ and H₂S, which are acid gases, and COS, CS₂, and RSH, which are sulfur compounds. In addition, the removal of acid gases using the absorbent composition according to the present invention can significantly reduce energy and investment costs compared with an existing acid gas removal process.

Description

Absorbent composition for acid gas removal comprising 2-amino 2-methyl 1-propanol (AMP) and method for removing acid gas using the same

The present invention relates to an absorbent composition for removing acid gas contained in natural gas, petroleum accompanying gas, syngas, process gas, and coal gasification gas by absorption method.

Gases produced in gas wells such as natural gas, and oils generated from refinery and petrochemical processes and synthesis gas processes contain acidic gases such as CO ₂ and H ₂ S. In addition to these compositions, sulfur compounds COS, CS ₂ and It often contains mercapatan.

Since the acid gas is an air pollutant, it is a material that must be removed before it can be shipped as a final product. In particular, in the petrochemical process, the acid gas is a material that must be removed due to catalyst poisoning in a post-stage process.

Commonly used acidic gas removal methods include physical absorption, chemical absorption, and mixed absorption combining physical absorption and chemical absorption. Among them, chemical absorption is a method using an amine aqueous solution at atmospheric pressure or high pressure. Typically, primary to tertiary such as mono ethanol amine (MEA), diethanolamine (DEA), triethanolamine (TEA), methyl diethanol amine (MDEA) Alkanolamine is mainly used.

However, in the case of chemical absorbents, CO ₂ and H ₂ S in acidic gases react very quickly and have high removal efficiency. However, in the case of COS, the absorption rate is more than 100 times slower than CO _2, so it is not easily removed in the absorption process.

In addition, mercaptans are sulfur compounds, but since the chemical structure is RSH (alkyl group), the acidic properties are less than those of other sulfur compounds, and are rather difficult to remove due to the characteristics of alkyl compounds.

Therefore, in order to remove COS and RSH, there are many processes using a method of installing an adsorption column after the absorption process and converting the COS to H ₂ S which can easily react with the absorption liquid through hydrolysis before some absorption towers. After the absorption process is also commercialized.

However, this method leads to an increase in costs due to the addition and operation of the equipment. In particular, a process employing a hydrolysis method for removing COS is heated to a reaction condition for hydrolyzing the entire raw gas to remove hundreds of ppm of COS. There is a disadvantage in that the energy consumption is much.

Therefore, in order to prevent the increase of the complexity of the process, investment cost and operating cost, a lot of inventions regarding the development of absorbents and processes capable of absorbing COS and RSH, as well as CO ₂ and H ₂ S have been proposed.

U.S. Patent US 2010-0154637 (Patent Document 1) reports that a mixture of alkanol amines such as MDEA or DEA with thiodiglycol improves the removal efficiency of RSH over conventional absorbents. It is explained that the absorption of the alkyl components also occurs at the same time, at which time an acceptable level of alkyl absorption occurs.

However, the RSH absorption efficiency of the absorbent according to the present invention is partially increased compared to the existing absorbent, but the absorption ability to remove the molecular sieve of the rear end by the removal of the above-described COS and RSH is not seen, and the rear end process is removed. In order to increase the amount of circulating absorbent liquid,

U.S. Patent No. 8313718 (Patent Document 2) is a mixture of H ₂ S and RSH by mixing a group such as sulfolane, a physical absorbent, MDEA, MEA, DEA, TEA, and diglycolamine (DGA), etc. It was suggested how to remove, but the removal efficiency was not great.

In addition, the removal of acidic gas from the mixed gas or liquid in this patent method uses a physical absorbent, so that a considerable amount of hydrocarbons will dissolve in the pressurization process, which will affect the treatment of the recovered sulfur compound at a later stage. Loss of methane, ethane and propane, which are both valuable and value-added in the product, can occur.

The present invention provides an absorbent composition for acid gas removal comprising AMP capable of removing sulfuric compounds such as COS, CS ₂ and RSH while simultaneously removing acid gases such as CO ₂ and H ₂ S contained in gas and liquid. Its purpose is to.

Another object of the present invention is to provide a method for removing acid gas through the acid gas removal absorbent composition composition comprising the AMP.

In order to achieve the above object, the present invention provides 11 to 24% by weight of 2-diethylaminoethanol (diethylethanolamine; DEEA), 8 to 18% by weight of 2-amino 2-methyl 1-propanol (AMP), It provides an absorbent composition for acidic gas removal comprising AMP, comprising 60 to 70% by weight of water and 1 to 3.5% by weight of piperazine-based compound.

To achieve another object, the present invention provides 11 to 24% by weight of 2-diethylaminoethanol, 8 to 18% by weight of 2-amino 2-methyl 1-propanol (AMP), 60 to 70% by weight of water. And preparing an absorbent comprising 1 to 3.5% by weight of piperazine-based compound; and

It provides an acid gas removal method comprising the step of absorbing the gaseous emissions containing acid gas to the absorbent.

According to the present invention, the absorbent composition for acidic gas removal comprising 2-Diethylaminoethanol, 2-amino 2-methyl 1-propanol (AMP), and AMP prepared by mixing water and piperazine When reacting with acid gas, the absorption rate of COS, CS ₂ and RSH as well as sulfur compounds CO ₂ and H ₂ S are significantly higher than those of commercially available absorbers. When using existing absorbents, adsorption towers and hydrolysis reactors, which are installed separately before and after the absorption process to remove COS and RSH, can be omitted, so that not only the required energy is significantly reduced, but also operating cost and facility investment cost are reduced. It works.

A and B in Figure 1 is an image showing an example of a conventional commercialized process for removing COS, RSH in acidic gas,

Figure 2 is an image showing an example of a simplified process than the conventional process when using the absorbent of the present invention,

3 is an image showing a device according to the invention,

A and B in Figure 4 is a graph showing the results of the continuous absorption regeneration experiment,

A and B in Figure 5 is a graph showing the results of the continuous absorption regeneration experiment using MDEA according to the composition ratio used in the existing commercial,

FIG. 6 shows absorption experiments using an absorbent mixed with 23 wt% 2-diethylaminoethanol, 9 wt% 2-amino2-methyl-1-propanol, 65 wt% water, and 3 wt% piperazine. Is a graph showing the results,

FIG. 7 shows absorption experiments using an absorbent mixed with 12 wt% 2-diethylaminoethanol, 18 wt% 2-amino 2-methyl 1-flopanol, 69 wt% water, and 1 wt% piperazine. Is a graph showing the results,

8 is a graph showing the results of an absorption experiment with an absorbent prepared by mixing 2-diethylaminoethanol with MDEA, water, and piperazine.

Hereinafter, the present invention will be described in more detail below.

The present invention provides 11 to 24% by weight of 2-diethylaminoethanol (diethylethanolamine; DEEA), 8 to 18% by weight of 2-amino 2-methyl 1-propanol (AMP), 60 to 70% by weight of water. And it provides an absorbent composition for acid gas removal comprising AMP, comprising 1 to 3.5% by weight of piperazine compound.

The present invention also relates to 11 to 24% by weight of 2-diethylaminoethanol, 8 to 18% by weight of 2-amino 2-methyl 1-propanol (AMP), 60 to 70% by weight of water and 1 to 3.5% by weight of Producing an absorbent comprising a piperazine-based compound; And it provides an acidic gas removal method comprising the step of absorbing the gaseous emission containing the acidic gas to the absorbent.

The 2-diethylaminoethanol (diethylethanolamine) absorbs and removes acidic gases, particularly COS and RSH, and contains 11 to 24 wt%. At this time, outside the above range may cause a problem that the absorption removal efficiency is lowered or the viscosity of the solution is increased, the cost is increased.

The 2-amino 2-methyl 1-propanol (AMP) belongs to a steric hindrance amine, and the steric amine has a low binding force between the amino group and the carbon dioxide according to the steric hindrance effect, and thus, compared with the conventional amine absorbent. Excellent characteristics in terms of stripping characteristics, energy consumption and absorbent loss ratio.

The 2-amino 2-methyl 1-propanol (AMP) includes 8 to 18% by weight, in which case the absorption efficiency may be lowered or the viscosity of the absorbent liquid may be increased if it is out of the range.

The piperazine compounds include piperazine, 2-methylpiperazine, 1,4-dimethylpiperazine, 1,4-diethylpiperazine, 2,3-dimethylpiperazine, 2,5-dimethylpiperazine, 2, 4-dimethylpiperazine, 1,4-dipropylpiperazine, 1,4-diisopropylpiperazine, 1- (2-aminoethyl) piperazine, 2-aminoethylpiperazine, 1- (2-hydroxyl Ethyl) piperazine, 1- (1-hydroxymethyl) piperazine, 1- (3-hydroxypropyl) piperazine, 1,4-bis (1-aminomethyl) piperazine, 1,4-bis (2 -Aminoethyl) piperazine, 1,4-bis (3-aminopropyl) piperazine and piperazinol, or any one or two or more combinations thereof, leading to improved absorption of COS and RSH. The piperazine-based compound contains 1 to 3.5% by weight, and may be added separately or mixed with an amine after being dissolved in water in advance. At this time, if the content of piperazine is out of the above range may cause a problem that the absorption rate of COS and RSH is lowered.

Therefore, the absorbent composition for acid gas removal including the AMP of the present invention has a higher absorption rate of COS, CS ₂ and RSH, as well as CO ₂ and H ₂ S, which are acid gases, compared to conventional commercial absorbers. In the case of using the absorbent of FIG. 1, the process may be simplified as shown in FIG. 2 instead of the complicated conventional process including the adsorption tower and the hydrolysis reactor separately at the front and rear of the absorption process as shown in a) and b) of FIG. 1. .

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by these examples.

<Example 1>

2-diethylaminoethanol, 2-amino 2-methyl 1-propanol (AMP), water, and piperazine were mixed at 18%, 13%, 66%, and 3% by weight, respectively, 120 ml of absorbent was prepared. A mixed gas of 5 vol% CO ₂ , 250 ppm COS and 450 ppm H ₂ S was fed to the absorption tower of the apparatus shown in FIG. 3 at a flow rate of 400 ml / min. The absorption liquid is supplied at a constant flow rate in the upper part of the absorption tower, and in this embodiment, the absorption liquid of the composition was supplied at a flow rate of 1.5 ml / min. The absorbent liquid from which the acidic gas was removed from the absorption tower was sent to a regeneration tower, regenerated at a temperature of 105 ° C, and sent to the absorption tower again to carry out a continuous absorption regeneration experiment to absorb the acidic gas.

As a result of analyzing the composition of the gas discharged from the upper part of the absorption tower as shown in a) and b) of FIG. 4, it was confirmed that CO ₂ , COS and H ₂ S were not discharged to the upper part of the absorption tower after the absorption was started.

Comparative Example 1

Comparative absorbent was prepared by mixing 40% by weight of MDEA, 5% by weight of piperazine and 55% by weight of water, and absorption and regeneration experiments were conducted under the same conditions as in Example 1.

As a result, as shown in a) and b) of FIG. 5, H ₂ S was completely absorbed, but CO ₂ and COS contained a considerable amount of gas discharged to the upper part of the absorption tower, and were not completely absorbed and removed.

<Example 2>

2-Diethylaminoethanol, 2-amino 2-methyl 1-propanol (AMP), water and piperazine were mixed at 23% by weight, 9% by weight, 65% by weight and 3% by weight, respectively. 120 ml of an absorbent was prepared, and absorption experiment was conducted under the same conditions as in Example 1.

As a result, as shown in Figure 6, after the initial absorption CO ₂ , COS and H ₂ S was confirmed that the complete absorption.

<Example 3>

2-diethylaminoethanol, 2-amino 2-methyl 1-propanol (AMP), water, and piperazine were mixed in 12 wt%, 18 wt%, 69 wt%, and 1 wt%, respectively, 120 ml of an absorbent was prepared, and the absorption experiment was conducted under the same conditions as in Example 1.

As a result, as shown in Figure 7, it was confirmed that the CO ₂ , COS and H ₂ S was completely absorbed and removed as in Examples 1 to ₂ .

Comparative Example 2

In order to compare with the present invention, the absorption experiment was performed by mixing 2-diethylaminoethanol and MDEA, which is a kind of alkanol amine.

2-Diethylaminoethanol, MDEA, water, and piperazine were mixed in the same manner as in Example 1 by mixing 12 wt%, 24 wt%, 61 wt%, and 3 wt%, respectively.

As a result, as shown in FIG. 8, CO ₂ . Absorption of H ₂ S and COS appears to occur well initially, but over time the concentrations of CO ₂ and COS have increased.

That is, although the absorption rate was good in the initial unreacted solution, it can be seen that the absorption capacity decreases over time such as a regeneration process. That is, even when a mixture of 2-diethylaminoethanol and alkanol amine was used as an absorbent, it was confirmed that the water absorption of the mixture composition of the present invention was not reached.

Taken together, 2-diethylaminoethanol of the present invention, 2-amino 2-methyl 1-propanol (AMP), absorbent for acid gas removal including AMP prepared by mixing water and piperazine When the composition reacts with acidic gas, the absorption rate of sulfur compounds such as COS as well as CO ₂ and H ₂ S, which are acidic gases, was much higher than that of MDEA, which is a commercially available absorbent.

In addition, in the absorbent mixed with 2-diethylaminoethanol, water and piperazine according to the composition of the present invention, in the case of including MDEA which is a kind of alkanolamine instead of AMP, the absorption rate of CO ₂ , COS and H ₂ S is It was confirmed that it was lower than the water absorption of the absorbent containing AMP of this invention.

The specific parts of the present invention have been described in detail above, and it is apparent to those skilled in the art that such specific descriptions are merely preferred embodiments, and thus the scope of the present invention is not limited thereto. something to do. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (4)

11-24 wt% 2-diethylaminoethanol (diethylethanolamine; DEEA), 8-18 wt% 2-amino 2-methyl 1-propanol (AMP), 60-70 wt% water and 1- An absorbent composition for removing acid gas, comprising AMP, comprising 3.5 wt% piperazine-based compound.

The method of claim 1,

The piperazine compounds include piperazine, 2-methylpiperazine, 1,4-dimethylpiperazine, 1,4-diethylpiperazine, 2,3-dimethylpiperazine, 2,5-dimethylpiperazine, 2, 4-dimethylpiperazine, 1,4-dipropylpiperazine, 1,4-diisopropylpiperazine, 1- (2-aminoethyl) piperazine, 2-aminoethylpiperazine, 1- (2-hydroxyl Ethyl) piperazine, 1- (1-hydroxymethyl) piperazine, 1- (3-hydroxypropyl) piperazine, 1,4-bis (1-aminomethyl) piperazine, 1,4-bis (2 -Aminoethyl) piperazine, 1,4-bis (3-aminopropyl) piperazine and piperazinol any one or a combination of two or more selected from the group consisting of AMP absorbent composition comprising an acid gas removal.

The method of claim 1,

The acid gas is absorbent composition for acid gas removal comprising AMP, characterized in that any one or a combination of two or more selected from the group consisting of CO ₂ , H ₂ S, COS and CS ₂ .

11-24 wt% 2-diethylaminoethanol, 8-18 wt% 2-amino 2-methyl 1-propanol (AMP), 60-70 wt% water and 1-3.5 wt% piperazine-based compound Preparing an absorbent comprising a; and

And absorbing the gaseous effluent containing acidic gas into the absorbent.

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