Composite amine absorbing solution, removal device and removal method

Abstract

To provide a composite amine absorbing liquid or the like that has a high reaction rate.SOLUTION: A composite amine absorbing liquid is for absorbing CO2 and / or H2S in a gas, and contains (a) a chain-like monoamine, (b) a diamine including amino groups having the same grade, (c) a chain-like diamine including amino groups having different grades, and (d) water.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a composite amine absorbent, a removal device and a removal method.

[0002] In recent years, the greenhouse effect of CO2 has been pointed out as one of the causes of global warming, and measures to prevent it have become urgently needed internationally to protect the global environment. Sources of CO2 include all fields of human activity that burn fossil fuels, and there is a tendency for the demand for reducing CO2 emissions to become stronger. Accordingly, methods for removing and capturing CO2 in combustion exhaust gas by contacting the combustion exhaust gas of a boiler with an amine-based CO2 absorbing solution, and methods for storing the captured CO2 without releasing it into the atmosphere, have been actively researched for power generation facilities such as thermal power plants that use a large amount of fossil fuels. In addition, as a process for removing and capturing CO2 from combustion exhaust gas using such a CO2 absorbing solution, a process is adopted in which the combustion exhaust gas is contacted with the CO2 absorbing solution in an absorption tower, the absorbing solution that has absorbed CO2 is heated in a regeneration tower to release CO2 and regenerate the absorbing solution, which is then circulated back to the absorption tower for reuse.

[0003] As a CO2 absorbing liquid, for example, an absorbing liquid containing a propanediamine compound has been proposed (see Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-296897 A [Patent Document 2] Special Publication No. 2007-527791 [Patent Document 3] Patent No. 4634384 [Patent Document 4] JP 2018-122278 A Summary of the Invention [Problem to be solved by the invention]

[0005] By using the absorbing liquid described in Patent Documents 1 to 4, at least one of CO2 and H2S contained in the gas to be treated can be separated from the gas by the absorbing liquid. Here, the faster the reaction rate of the absorbing liquid, the more efficiently it can recover the CO2 and H2S to be absorbed.

[0006] In view of the above problems, an object of the present disclosure is to provide a composite amine absorbing solution, a removal device, and a removal method that have a faster reaction rate. [Means for solving the problem]

[0007] The composite amine absorbing solution of the present disclosure for solving the above-mentioned problems is a composite amine absorbing solution that absorbs at least one of CO2 and H2S in a gas, and includes (a) a chain monoamine, (b) a diamine containing amino groups of the same rank, (c) a chain diamine containing amino groups of different ranks, and (d) water.

[0008] The removal device of the present disclosure for solving the above-mentioned problems includes an absorption tower that contacts a gas containing at least one of CO2 and H2S with an absorption liquid to remove at least one of CO2 and H2S, and an absorption liquid regenerator that regenerates the solution that has absorbed at least one of CO2 and H2S, and reuses the solution regenerated by removing at least one of CO2 and H2S in the absorption liquid regenerator in the absorption tower, and uses the composite amine absorption liquid described above.

[0009] The removal method of the present disclosure for solving the above-mentioned problems comprises contacting a gas containing at least one of CO2 and H2S with an absorption liquid to remove at least one of CO2 and H2S in an absorption tower, regenerating the solution having absorbed at least one of CO2 and H2S in an absorption liquid regeneration tower, and reusing the regenerated solution obtained by removing at least one of CO2 and H2S in the absorption liquid regeneration tower in the absorption tower, and the above-mentioned composite amine absorption liquid is used. Effect of the Invention

[0010] According to the present disclosure, (a) a linear monoamine, (b) a diamine, and (c) a chain diamine containing amino groups of different grades are dissolved in water to prepare an absorption liquid, which is entangled in a complex manner, and the synergistic effect of these components improves the absorption of CO2, H2S, or both, and the flow rate of the absorption liquid and the height of the absorption tower can be reduced. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a CO2 recovery device using an absorbing solution according to the present disclosure. [Diagram 2] FIG. 2 is a diagram showing the results of the increase rate of the reaction rate between the Examples in Table 1 and the first Comparative Example. [Diagram 3] FIG. 3 is a diagram showing the results of the increase rate of the reaction rate between the Example in Table 1 and the second comparative example. [Figure 4] FIG. 4 is a diagram showing the results of the increase rate of the reaction rate between the Examples in Table 2 and the first Comparative Example. [Diagram 5] FIG. 5 is a diagram showing the results of the increase rate of the reaction rate between the Examples in Table 2 and the second comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes combinations of the embodiments.

[0013] The composite amine absorbing liquid according to the present disclosure is a composite amine absorbing liquid that absorbs at least one of CO2 and H2S in a gas, and includes (a) a chain monoamine, (b) a diamine containing an amino group of the same grade, (c) a chain diamine containing an amino group of a different grade, and (d) water. That is, (a) a chain monoamine, (b) a diamine containing an amino group of the same grade, and (c) a chain diamine containing an amino group of a different grade are dissolved in water to form a liquid. In the present disclosure, (a) a chain monoamine, (b) a diamine containing an amino group of the same grade, and (c) a chain diamine containing an amino group of a different grade are dissolved in water to form an absorbing liquid, which is entangled in a complex manner, and the synergistic effect of these improves the absorbency of CO2 or H2S or both for a gas containing at least one of CO2 and H2S. That is, the reaction rate of the absorbing liquid can be increased.

[0014] Here, the (a) linear monoamine (component a) includes at least one of a primary linear monoamine (component a1, a primary linear monoalkanolamine), a secondary linear monoamine (component a2, a secondary linear monoalkanolamine), and a tertiary linear monoamine (component a3, a tertiary linear monoalkanolamine). In addition, it may be a two-component linear amine combination of a primary linear monoamine and a secondary linear monoamine, a two-component linear amine combination of a primary linear monoamine and a tertiary linear monoamine, or even a three-component linear amine combination of a primary linear monoamine, a secondary linear monoamine, and a tertiary linear monoamine.

[0015] In addition, the primary linear monoamine (a1 component, primary chain monoalkanolamine) is preferably a primary monoamine with low steric hindrance (a1L component) or a primary monoamine with high steric hindrance (a1H component). Here, in the primary linear monoamine, the primary monoamine with low steric hindrance (a1L component) may be, for example, at least one selected from monoethanolamine (MEA), 3-amino-1-propanol, 4-amino-1-butanol, and diglycolamine. These may be combined.

[0016] In addition, in the primary linear monoamine, the primary monoamine (a1H component) having high steric hindrance is preferably a compound represented by the chemical formula shown in "Chemical Formula 1" below. [ka]

[0017] Specifically, examples of the highly sterically hindered primary monoamine (a1H component) include compounds selected from at least one of 2-amino-1-propanol (2A1P), 2-amino-1-butanol (2A1B), 2-amino-3-methyl-1-butanol (AMB), 1-amino-2-propanol (1A2P), 1-amino-2-butanol (1A2B), 2-amino-2-methyl-1-propanol (AMP), etc., but the present disclosure is not limited thereto. These may also be combined.

[0018] The secondary linear monoamine (a2) is preferably a compound represented by the chemical formula shown in "Chemical Formula 2" below. [ka]

[0019] Specifically, the secondary linear monoamine (2a, secondary chain monoalkanolamine) may be, for example, a compound selected from at least one of N-methylaminoethanol, N-ethylaminoethanol, N-propylaminoethanol, N-butylaminoethanol, etc., but the present disclosure is not limited thereto. These may also be combined.

[0020] The tertiary linear monoamine (a3) ​​is preferably a compound represented by the chemical formula shown in Chemical Formula 3 below. [ka]

[0021] Specifically, examples of the tertiary linear monoamine (a3, tertiary chain monoalkanolamine) include compounds selected from at least one of N-methyldiethanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, 4-dimethylamino-1-butanol, 2-dimethylaminoethanol, 2-diethylaminoethanol, 2-di-n-butylaminoethanol, N-ethyl-N-methylethanolamine, 3-dimethylamino-1-propanol, and 2-dimethylamino-2-methyl-1-propanol, but the present disclosure is not limited thereto. These may also be combined.

[0022] The diamine (component b) containing an amino group having the same grade as (b) preferably contains at least one of a primary linear polyamine, a secondary linear polyamine, and a secondary cyclic polyamine.

[0023] Here, the primary linear polyamine group may be, for example, a compound selected from at least one of ethylenediamine (EDA), propanediamine (PDA), etc., but the present disclosure is not limited thereto. The secondary linear polyamine group may be, for example, a compound selected from at least one of N,N'-dimethylethylenediamine (DMEDA), N,N'-diethylethylenediamine (DEEDA), N,N'-dimethylpropanediamine (DMPDA), etc., but the present disclosure is not limited thereto. These may be combined.

[0024] In addition, the secondary cyclic polyamine may be, for example, a compound selected from at least one of piperazine (PZ), 2-methylpiperazine (2MPZ), 2,5-dimethylpiperazine (DMPZ), etc., but the present disclosure is not limited thereto. These may also be combined.

[0025] The chain diamine containing amino groups of different grades (c) contains two grades of amino groups selected from the group consisting of primary amino groups, secondary amino groups, and tertiary amino groups. The chain diamine containing amino groups of different grades (c) preferably contains at least one chain diamine containing a tertiary amino group. Furthermore, the chain diamine containing amino groups of different grades (c) more preferably contains at least one chain diamine containing a tertiary amino group and a primary amino group.

[0026] The chain diamine containing a tertiary amino group and a primary amino group is exemplified by at least one selected from N,N-diethylpropanediamine, N,N-dibutylpropanediamine, and the like.

[0027] In addition, the chain diamine containing amino groups of different grades (c) more preferably contains at least one chain diamine containing a tertiary amino group and a secondary amino group. Examples of the chain diamine containing a tertiary amino group and a secondary amino group include at least one selected from N,N,N'-trimethylpropanediamine, N,N,N'-triethylpropanediamine, N'-ethyl-N,N-dimethylpropanediamine, N,N-diethyl-N'-methylpropanediamine, etc.

[0028] Next, the blending ratio of each component (a component, b component, c component) is preferably specified as follows. The total concentration of the linear monoamine (a component) of (a) and the diamine (b component) containing the same grade of amino group of (b) is preferably 20% by weight or more and 65% by weight or less of the entire absorbing liquid, and more preferably 30% by weight or more and 60% by weight or less of the entire absorbing liquid. By setting it in this range, it is possible to make the absorbing liquid function well. The linear monoamine (a component) of (a) is preferably 15% by weight or more and 60% by weight or less of the entire absorbing liquid, and more preferably 20% by weight or more and 55% by weight or less of the entire absorbing liquid. The diamine (b component) containing the same grade of amino group of (b) is preferably 1% by weight or more and 15% by weight or less of the entire absorbing liquid, and more preferably 2% by weight or more and 10% by weight or less of the entire absorbing liquid. The amount of the chain diamine containing amino groups of different grades (c) is preferably more than 5% by weight and not more than 35% by weight of the entire absorbing liquid, and more preferably more than 9% by weight and not more than 25% by weight of the entire absorbing liquid.

[0029] The blending ratio of the (a) linear monoamine (component a) to the (b) diamine containing an amino group of the same grade (component b) and the (c) chain diamine containing an amino group of a different grade (component c) is such that the weight ratio of ((b) diamine containing an amino group of the same grade + (c) chain diamine containing an amino group of a different grade) / ((a) chain monoamine) is 0.16 or more and 3.5 or less, that is, 0.16≦(b+c) / a≦3.5, and more preferably 0.23≦(b+c) / a≦1.5.

[0030] In addition, the blending ratio of (b) diamines containing amino groups of the same grade and (c) chain diamines containing amino groups of different grades is 、( c) Chain diamines containing amino groups of different grades / (b) is a diamine containing an amino group having the same grade It is preferable that the weight ratio of is 1 or more and 16.5 or less, that is, 1≦ c / b It is preferable that the blending ratio is ≦16.5, and 3≦ c / bIt is more preferable to have a composition of ≦12.5.

[0031] The blending ratio (wt %) of water (component d) is the remainder by weight of the total weight of (a) linear monoamine, (b) diamine containing amino groups of the same grade, and (c) chain diamine containing amino groups of different grades, which is the weight ratio of water.

[0032] In the present disclosure, the absorption temperature of the absorption tower in the chemical absorption method when contacting with exhaust gas containing, for example, CO2, is preferably usually in the range of 30 to 80° C. In addition, a corrosion inhibitor, a deterioration inhibitor, etc. may be added to the absorption liquid used in the present disclosure as necessary.

[0033] In addition, the CO2 partial pressure at the inlet of the CO2 absorber during absorption of CO2 in the gas to be treated is preferably low (for example, 0.003 to 0.1 MPa) in terms of application of the chemical absorption method.

[0034] In the present disclosure, the regeneration temperature in the regeneration tower that releases CO2 and the like from the absorbing solution that has absorbed CO2 and the like is preferably 110°C or higher at the bottom of the absorbing solution regeneration tower when the pressure inside the regeneration tower is 130 to 200 kPa (absolute pressure). This is because regeneration at less than 110°C requires a large amount of circulating absorbing solution in the system, which is not preferable from the viewpoint of regeneration efficiency. Regeneration at 115°C or higher is more preferable.

[0035] Examples of gases that can be treated according to the present disclosure include, but are not limited to, coal gasification gas, synthesis gas, coke oven gas, petroleum gas, and natural gas. Any gas containing acidic gases such as CO2 and H2S can be used.

[0036] The process that can be adopted in the method of removing CO2 or H2S or both in gas according to the present disclosure is not particularly limited, but an example of a removal apparatus for removing CO2 will be described with reference to FIG.

[0037] FIG. 1 is a schematic diagram showing the configuration of a CO2 recovery device according to the first embodiment. As shown in FIG. 1, the CO2 recovery device 12 according to the first embodiment includes an exhaust gas cooling device 16 that cools an exhaust gas 14 containing CO2 and O2 discharged from an industrial combustion facility 13 such as a boiler or a gas turbine by cooling water 15, a CO2 absorption tower 18 having a CO2 recovery section 18A that removes CO2 from the exhaust gas 14 by contacting the cooled CO2-containing exhaust gas 14 with a CO2 absorbing liquid (hereinafter also referred to as an "absorbing liquid") 17 that absorbs CO2, and an absorbing liquid regeneration tower 20 that releases CO2 from the CO2 absorbing liquid (hereinafter also referred to as a "rich solution") 19 that has absorbed CO2 and regenerates the CO2 absorbing liquid. In the CO2 recovery device 12, the regenerated CO2 absorbing liquid (hereinafter also referred to as a "lean solution") 17 from which CO2 has been removed in the absorbing liquid regeneration tower 20 is reused as a CO2 absorbing liquid in the CO2 absorption tower 18.

[0038] In Fig. 1, reference numeral 13a denotes a flue, 13b denotes a chimney, and 34 denotes steam condensate. The CO2 capture device 12 may be installed later to capture CO2 from an existing flue gas source, or may be installed simultaneously with a new flue gas source. An openable damper is installed in the flue gas 14 line, and is opened when the CO2 capture device 12 is in operation. The flue gas source is in operation, but is set to close when the operation of the CO2 capture device 12 is stopped.

[0039] In the CO2 capture method using this CO2 capture device 12, first, exhaust gas 14 containing CO2 from industrial combustion equipment 13 such as a boiler or gas turbine is pressurized by an exhaust gas blower 22 and then sent to an exhaust gas cooling device 16, where it is cooled by cooling water 15 and sent to a CO2 absorption tower 18.

[0040] In the CO2 absorption tower 18, the flue gas 14 comes into countercurrent contact with the CO2 absorbing solution 17, which is the amine absorbing solution according to this embodiment, and the CO2 in the flue gas 14 is absorbed by the CO2 absorbing solution 17 through a chemical reaction. The CO2-removed flue gas from which the CO2 has been removed in the CO2 capture section 18A comes into gas-liquid contact with the circulating wash water 21 containing the CO2 absorbing solution, which is supplied from a nozzle in the water washing section 18B in the CO2 absorption tower 18, and the CO2 absorbing solution 17 accompanying the CO2-removed flue gas is recovered, and then the flue gas 23 from which the CO2 has been removed is discharged outside the system. In addition, the rich solution 19, which is the CO2 absorbing solution that has absorbed the CO2, is pressurized by the rich solution pump 24, and is heated in the rich-lean solution heat exchanger 25 by the lean solution, which is the CO2 absorbing solution 17 regenerated in the absorbing solution regenerator 20, and is supplied to the absorbing solution regenerator 20.

[0041] The rich solution 19 discharged from the top of the absorbent regenerator 20 into the inside undergoes an endothermic reaction with steam supplied from the bottom, releasing most of the CO2. The CO2 absorbing solution from which some or most of the CO2 has been released in the absorbent regenerator 20 is called a semi-lean solution. By the time this semi-lean solution reaches the bottom of the absorbent regenerator 20, it becomes a CO2 absorbing solution (lean solution) 17 from which almost all of the CO2 has been removed. A part of this lean solution 17 is superheated by steam 27 in the reboiler 26, and supplies steam for CO2 desorption to the inside of the absorbent regenerator 20.

[0042] On the other hand, from the top of the absorbent regenerator 20, CO2-bearing gas 28 accompanied with water vapor released from the rich solution 19 and the semi-lean solution in the tower is drawn out, the water vapor is condensed by the condenser 29, water is separated in the separation drum 30, and CO2 gas 40 is discharged outside the system, compressed by a separate compressor 41, and recovered. This compressed and recovered CO2 gas 42 passes through a separation drum 43 and is then injected into an oil field using enhanced oil recovery (EOR) or stored in an aquifer to combat global warming. The reflux water 31 separated and refluxed from the CO2-bearing gas 28 accompanied with water vapor in the separation drum 30 is supplied to the top of the absorbent regenerator 20 and the wash water 21 side by a reflux water circulation pump 35, respectively. The regenerated CO2 absorbing liquid (lean solution) 17 is cooled by the rich solution 19 in the rich-lean solution heat exchanger 25, then pressurized by the lean solution pump 32, and further cooled by the lean solution cooler 33, and then supplied into the CO2 absorbing tower 18. Note that this embodiment merely describes the outline, and some of the associated equipment is omitted in the description.

[0043] Below, a description will be given of suitable test examples that demonstrate the effects of the present disclosure, but the present disclosure is not limited thereto.

[0044] [Test example] Absorption of CO2 was carried out using an absorption test device not shown. Figures 2 and 3 are diagrams showing the results of measuring the relationship between the absorption speed of a three-component composite amine absorbing solution (a solution of a linear monoamine (component a), a diamine containing the same amino group grade (component b), and a chain diamine containing an amino group grade different from that of the other (component c) dissolved in water (component d) in Test Examples 1-1 to 1-20 and a comparative example. The components of the test examples are listed in Table 1 below.

[0045] [Table 1]

[0046] [Test Examples 1-1 to 1-3] In Test Example 1-1, monoethanolamine was used as the linear monoamine (a component), propanediamine was used as the diamine (b component) containing the same grade of amino group (b component), and N,N-diethylpropanediamine was used as the chain diamine (c component) containing a different grade of amino group (c component), and these were dissolved and mixed in water (d component) to prepare an absorption liquid. In Test Example 1, the weight ratio of (b+c) / a was 1.0, and the weight ratio of c / b was 10.5.

[0047] In Test Example 1-2, the same amine components as in Test Example 1-1 were used, and the blending ratios were (b+c) / a (weight ratio) 1.5 and c / b (weight ratio) 12.5. In Test Example 1-3, the same amine components as in Test Example 1-1 were used, and the blending ratios were (b+c) / a (weight ratio) 3.5 and c / b (weight ratio) 16.5.

[0048] Next, in Test Examples 1-4 to 1-20, the amine components were changed from those in Test Example 1-1, and the weight ratio of (b+c) / a was set to 0.16 or more and 3.5 or less, and the weight ratio of c / b was set to 1 or more and 16.5 or less.

[0049] In Test Example 1-4, an absorbing liquid having the same composition as Test Example 1-1 was used, except that the chain diamine (component c) containing an amino group having a different grade of (c) was changed to N,N-dibutylpropanediamine.

[0050] In Test Example 1-5, an absorbing liquid of the same composition as in Test Example 1-1 was used, except that the linear monoamine (component a) in (a) was replaced with 2-amino-2-methyl-1-propanol and monoethanolamine.

[0051] In Test Example 1-6, an absorption liquid of the same composition as in Test Example 1-1 was used, except that (a) the linear monoamine (component a) was 2-amino-2-methyl-1-propanol and N-ethylaminoethanol, and (b) the diamine containing an amino group of the same grade (component b) was piperazine.

[0052] In Test Example 1-7, an absorbing solution of the same composition as in Test Example 1-6 was used, except that the linear monoamine (component a) in (a) was changed to 2-amino-2-methyl-1-propanol and N-butylaminoethanol.

[0053] In Test Example 1-8, an absorbing liquid of the same composition as in Test Example 1-6 was used, except that the linear monoamine (component a) in (a) was changed to 2-amino-2-methyl-1-propanol and N-methyldiethanolamine.

[0054] In Test Example 1-9, an absorbing liquid of the same composition as in Test Example 1-6 was used, except that the linear monoamine (component a) in (a) was changed to 2-amino-2-methyl-1-propanol and N-ethyldiethanolamine.

[0055] In Test Example 1-10, an absorption liquid of the same composition as in Test Example 1-1 was used, except that (a) the linear monoamine (component a) was N-ethylaminoethanol, and (b) the diamine containing an amino group of the same grade (component b) was 2-methylpiperazine.

[0056] In Test Example 1-11, an absorbing solution of the same composition as in Test Example 1-10 was used, except that the diamine (component b) containing an amino group having the same grade as that of (b) was replaced with piperazine.

[0057] In Test Example 1-12, an absorption liquid of the same composition as in Test Example 1-1 was used, except that (a) the linear monoamine (component a) was N-butylaminoethanol, and (b) the diamine containing an amino group of the same grade (component b) was 2-methylpiperazine.

[0058] In Test Example 1-13, an absorbing solution of the same composition as in Test Example 1-12 was used, except that the diamine (component b) containing an amino group having the same grade as that of (b) was replaced with piperazine.

[0059] In Test Example 1-14, an absorbing solution of the same composition as in Test Example 1-12 was used, except that the diamine (component b) containing an amino group having the same grade as that of (b) was changed to N,N'-dimethylpropanediamine.

[0060] In Test Example 1-15, an absorption liquid of the same composition as in Test Example 1-1 was used, except that the linear monoamine (component a) in (a) was N-ethylaminoethanol and N-methyldiethanolamine, and the diamine (component b) containing an amino group of the same grade in (b) was piperazine.

[0061] In Test Example 1-16, an absorbing solution of the same composition as in Test Example 1-15 was used, except that the linear monoamine (component a) in (a) was changed to N-ethylaminoethanol and N-ethyldiethanolamine.

[0062] In Test Example 1-17, an absorbing solution of the same composition as in Test Example 1-15 was used, except that the linear monoamine (component a) in (a) was changed to N-butylaminoethanol and N-methyldiethanolamine.

[0063] In Test Example 1-18, an absorbing solution of the same composition as in Test Example 1-15 was used, except that the linear monoamine (component a) in (a) was changed to N-butylaminoethanol and N-ethyldiethanolamine.

[0064] In Test Example 1-19, an absorption liquid of the same composition as in Test Example 1-1 was used, except that the linear monoamine (component a) in (a) was N-methyldiethanolamine and 2-amino-2-methyl-1-propanol, and the diamine (component b) containing an amino group of the same grade in (b) was N,N'-dimethylpropanediamine.

[0065] In Test Example 1-20, an absorption liquid of the same composition as in Test Example 1-1 was used, except that the linear monoamine (component a) in (a) was N-ethyldiethanolamine and 2-amino-2-methyl-1-propanol, and the diamine (component b) containing an amino group of the same grade in (b) was N,N'-dimethylpropanediamine.

[0066] The rate at which the absorbing solution absorbed CO2 was measured for each of the above test examples. The test conditions were a temperature of 40°C and a CO2 partial pressure of 10 kPa. As a comparative example, an absorbing solution was prepared for each test example in which the weight amount of the component of the chain diamine containing amino groups of different grades (c) was replaced by the linear monoamine (a), and the same absorption rate was calculated. For each test example, the comparative example was set to 1, and the results of calculating the increase rate of the reaction rate of the test example are shown in Figure 2.

[0067] As another comparative example, the increase rate of the reaction rate in each test example was calculated using an absorbing liquid containing 30% by weight (30 w%) of monoethanolamine as the amine component as a reference, and the results are shown in FIG.

[0068] Next, the absorption rate of an absorbing solution using N,N-diethylpropanediamine as the component of the chain diamine containing amino groups of different grades (c) with a total concentration of amines of 55w% was compared with that of an absorbing solution using N,N,N',N'-tetramethylpropanediamine as a comparative example instead of the chain diamine containing amino groups of different grades (c). As a result, the reaction rate of the absorbing solution using the component of the chain diamine containing amino groups of different grades (c) increased by 94%. In other words, the reaction rate was 1.94 times higher.

[0069] Next, we will explain the test examples in which the chain diamine containing amino groups of different grades (c) was changed. Figures 4 and 5 are diagrams showing the results of measuring the relationship between the absorption speed of a three-component composite amine absorbing solution (a solution in which a linear monoamine (component a), a diamine containing amino groups of the same grade (component b), and a chain diamine containing amino groups of different grades (component c) are dissolved in water (component d)) in test examples 2-1 to 2-21 and a comparative example. The components of the test examples are listed in [Table 2] below.

[0070] [Table 2]

[0071] [Test Examples 2-1 to 2-3] In Test Example 2-1, monoethanolamine was used as the linear monoamine (a component) in (a), propanediamine was used as the diamine (b component) containing the same grade of amino group in (b), and N,N-trimethylpropanediamine was used as the chain diamine (c component) containing a different grade of amino group in (c), and these were dissolved and mixed in water (d component) to prepare an absorption liquid. In Test Example 2, the weight ratio of (b+c) / a was 1.0, and the weight ratio of c / b was 10.5.

[0072] In Test Example 2-2, the same amine components as in Test Example 2-1 were used, and the blending ratios were (b+c) / a (weight ratio) 1.5 and c / b (weight ratio) 12.5. In Test Example 2-3, the same amine components as in Test Example 2-1 were used, and the blending ratios were (b+c) / a (weight ratio) 3.5 and c / b (weight ratio) 16.5.

[0073] Next, in Test Examples 2-4 to 2-21, the amine components were changed from those in Test Example 2-1, and the weight ratio of (b+c) / a was set to 0.16 or more and 3.5 or less, and the weight ratio of c / b was set to 1 or more and 16.5 or less.

[0074] In Test Example 2-4, the absorption liquid had the same composition as Test Example 2-1, except that the chain diamine (component c) containing an amino group of a different grade (c) was changed to N,N,N'-triethylpropanediamine.

[0075] In Test Example 2-5, an absorbing solution of the same composition as in Test Example 2-1 was used, except that the chain diamine (component c) containing an amino group of a different grade in (c) was changed to N'-ethyl-N,N-dimethylpropanediamine.

[0076] In Test Example 2-6, an absorbing solution of the same composition as in Test Example 2-1 was used, except that the chain diamine (component c) containing an amino group of a different grade in (c) was changed to N,N-diethyl-N'-methylpropanediamine.

[0077] In Test Example 2-7, an absorption liquid of the same composition as in Test Example 2-1 was used, except that the linear monoamine (component a) in (a) was 2-amino-2-methyl-1-propanol and monoethanolamine, and the diamine (component b) containing an amino group of the same grade in (b) was piperazine.

[0078] In Test Example 2-8, an absorbing solution of the same composition as in Test Example 2-7 was used, except that the linear monoamine (component a) in (a) was changed to 2-amino-2-methyl-1-propanol and N-ethylaminoethanol.

[0079] In Test Example 2-9, an absorbing solution of the same composition as in Test Example 2-7 was used, except that the linear monoamine (component a) in (a) was changed to 2-amino-2-methyl-1-propanol and N-butylaminoethanol.

[0080] In Test Example 2-10, an absorption liquid of the same composition as in Test Example 2-1 was used, except that (a) the linear monoamine (component a) was N-ethylaminoethanol, and (b) the diamine containing an amino group of the same grade (component b) was 2-methylpiperazine.

[0081] In Test Example 2-11, an absorbing solution of the same composition as in Test Example 2-10 was used, except that the diamine (component b) containing an amino group having the same grade as that of (b) was replaced with piperazine.

[0082] In Test Example 2-12, an absorption liquid of the same composition as in Test Example 2-1 was used, except that (a) the linear monoamine (component a) was N-butylaminoethanol, and (b) the diamine containing an amino group of the same grade (component b) was 2-methylpiperazine.

[0083] In Test Example 2-13, an absorbing solution of the same composition as in Test Example 2-12 was used, except that the diamine (component b) containing an amino group having the same grade as that of (b) was replaced with piperazine.

[0084] In Test Example 2-14, an absorbing solution of the same composition as in Test Example 2-12 was used, except that the diamine (component b) containing an amino group having the same grade as that of (b) was changed to N,N'-dimethylpropanediamine.

[0085] In Test Example 2-15, an absorption solution of the same composition as in Test Example 2-1 was used, except that the linear monoamine (component a) in (a) was N-ethylaminoethanol and N-methyldiethanolamine, and the diamine (component b) containing an amino group of the same grade in (b) was piperazine.

[0086] In Test Example 2-16, an absorbing solution of the same composition as in Test Example 2-15 was used, except that the linear monoamine (component a) in (a) was changed to N-ethylaminoethanol and N-ethyldiethanolamine.

[0087] In Test Example 2-17, an absorbing solution of the same composition as in Test Example 2-15 was used, except that the linear monoamine (component a) in (a) was changed to N-butylaminoethanol and N-methyldiethanolamine.

[0088] In Test Example 2-18, an absorbing solution of the same composition as in Test Example 2-15 was used, except that the linear monoamine (component a) in (a) was changed to N-butylaminoethanol and N-ethyldiethanolamine.

[0089] In Test Example 2-19, an absorbing liquid of the same composition as in Test Example 2-15 was used, except that the linear monoamine (component a) in (a) was changed to 3-dimethylamino-1-propanol.

[0090] In Test Example 2-20, an absorption liquid of the same composition as in Test Example 2-1 was used, except that the linear monoamine (component a) in (a) was N-methyldiethanolamine and 2-amino-2-methyl-1-propanol, and the diamine (component b) containing an amino group of the same grade in (b) was N,N'-dimethylpropanediamine.

[0091] In Test Example 2-21, an absorption liquid of the same composition as in Test Example 2-1 was used, except that the linear monoamine (component a) in (a) was N-ethyldiethanolamine and 2-amino-2-methyl-1-propanol, and the diamine (component b) containing an amino group of the same grade in (b) was N,N'-dimethylpropanediamine.

[0092] As a comparative example, an absorption solution was prepared in which the weight amount of the chain diamine component containing amino groups of different grades (c) was replaced with the linear monoamine (a) for each test example, and the absorption rate was calculated in the same manner. The increase rate of the reaction rate of each test example was calculated by setting the comparative example to 1, and the results are shown in Figure 4.

[0093] As another comparative example, the increase rate of the reaction rate in each test example was calculated using an absorbing liquid containing 30% by weight (30 w%) of monoethanolamine as the amine component as a reference, and the results are shown in FIG.

[0094] Next, the absorption rate of an absorbing liquid using N,N,N'-trimethylpropanediamine as the component of the chain diamine containing amino groups of different grades (c) with a total concentration of amines of 55w% was compared with that of an absorbing liquid using N,N,N',N'-tetramethylpropanediamine instead of the chain diamine containing amino groups of different grades (c) as a comparative example. As a result, the reaction rate of the absorbing liquid using the component of the chain diamine containing amino groups of different grades (c) increased by 124%. In other words, the reaction rate was 2.24 times higher.

[0095] As shown in the above test examples, by using a composite amine absorbing liquid containing (a) a chain monoamine, (b) a diamine containing an amino group of the same grade, (c) a chain diamine containing an amino group of a different grade, and (d) water, the reaction rate as an absorbing liquid can be increased and the performance as an absorbing liquid can be improved. In particular, by containing (c) a chain diamine containing an amino group of a different grade, the performance of the absorbing liquid can be improved compared to the case where a chain diamine containing an amino group of the same grade is contained or the absorbing liquid composed only of (a) a chain monoamine and (b) a diamine containing an amino group of the same grade.

[0096] Furthermore, the (c) chain diamine containing amino groups of different grades can have a faster absorption rate by including at least one chain diamine containing a tertiary amino group and a primary amino group or at least one chain diamine containing a tertiary amino group and a secondary amino group. In particular, the (c) chain diamine containing amino groups of different grades can have a faster absorption rate by including at least one chain diamine containing a tertiary amino group and a secondary amino group. [Explanation of symbols]

[0097] 12 CO2 capture equipment 13 Industrial combustion facilities 14 Exhaust gas 16 Exhaust gas cooling device 17 CO2 absorbing solution (lean solution) 18 CO2 Absorption Tower 19 CO2 absorbing solution (rich solution) 20 Absorbent regeneration tower 21 Washing water

Claims

1. CO in the gas 2 and H 2 A composite amine absorbing solution for absorbing at least one of (a) a chain monoamine; (b) a diamine containing the same grade of amino groups; (c) acyclic diamines containing amino groups of different ranks; (d) water, The chain monoamine (a) accounts for 15% by weight or more and 60% by weight or less of the total weight of the absorbing liquid, (b) The diamine containing an amino group having the same grade is 1% by weight or more and 15% by weight or less of the total absorbing liquid, (c) The chain diamine containing an amino group having a different grade is more than 5% by weight and not more than 35% by weight of the entire absorbing liquid, The weight ratio of the chain diamine containing an amino group having a different grade (c) to the diamine containing an amino group having the same grade (b) is 1 or more and 16.5 or less. A composite amine absorbent.

2. 2. The composite amine absorbing solution according to claim 1, wherein the chain monoamine (a) comprises at least one of a primary chain monoalkanolamine, a secondary chain monoalkanolamine, and a tertiary chain monoalkanolamine.

3. 3. The composite amine absorbing solution according to claim 1 or 2, wherein the diamines containing amino groups of the same grade in (b) include at least one of a primary chain polyamine, a secondary chain polyamine, and a secondary cyclic polyamine.

4. The composite amine absorbing solution according to any one of claims 1 to 3, wherein the chain diamines containing amino groups of different grades (c) include at least one chain diamine containing a tertiary amino group.

5. The composite amine absorbing solution according to any one of claims 1 to 3, wherein the chain diamine containing amino groups of different grades (c) includes at least one chain diamine containing a tertiary amino group and a primary amino group.

6. The composite amine absorbing solution according to any one of claims 1 to 3, wherein the chain diamine containing amino groups of different grades (c) includes at least one chain diamine containing a tertiary amino group and a secondary amino group.

7. 7. The composite amine absorbing solution according to claim 1, wherein a total concentration of the chain monoamine (a) and the diamine containing amino groups of the same grade (b) is 20 mass% to 65 weight% of the entire absorbing solution.

8. 8. The composite amine absorbing solution according to claim 1, wherein a weight ratio of ((b) diamine containing amino groups of the same grade + (c) chain diamine containing amino groups of different grades) / ((a) chain monoamine) is 0.16 or more and 3.5 or less.

9. CO 2 and H 2 A gas containing at least one of CO and S is contacted with an absorbing liquid to produce CO 2 and H 2 an absorption tower for removing at least one of S and CO 2 and H 2 and an absorption liquid regeneration tower for regenerating a solution that has absorbed at least one of CO and S. 2 and H 2 A removal apparatus for reusing a solution regenerated by removing at least one of S in the absorption tower, A removal apparatus using the composite amine absorbing solution according to any one of claims 1 to 8.

10. The absorption tower has an absorption temperature of 30 to 80° C. The removal apparatus according to claim 9, wherein the absorbent regenerator has a regeneration temperature of 110° C. or higher.

11. CO 2 and H 2 A gas containing at least one of CO and S is contacted with an absorbing liquid to produce CO 2 and H 2 At least one of S and CO is removed in the absorption tower. 2 and H 2 The solution that has absorbed at least one of the above-mentioned sulfuric acid and sulfuric acid is regenerated in an absorbent regenerator, and the absorbent regenerator is used to regenerate the solution. 2 and H 2 A method for removing at least one of S and regenerating a solution in the absorption tower, comprising: A method for removing amines, comprising using the composite amine absorbing solution according to any one of claims 1 to 8.

12. The absorption temperature of the absorption tower is 30 to 80° C., The method according to claim 11, wherein the regeneration temperature of the absorbent regeneration tower is 110°C or higher.

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