Method for regenerating COS hydrolysis catalyst

Abstract

A method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst for hydrolyzing COS which is contained in a gas obtained by gasifying a carbon material, wherein a spent COS hydrolysis catalyst is immersed in an acid solution for a prescribed time thereby removing poisoning substances adhering to the surface of the COS hydrolysis catalyst; and thus regenerating the COS hydrolysis catalyst.

Claims

1. A method for regenerating a carbonyl sulfide (COS) conversion catalyst by hydrolyzing COS which is contained in a gas obtained by gasifying a carbon raw material, wherein a spent COS hydrolysis catalyst is immersed in an acid solution for a prescribed amount of time.

2. A method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst by hydrolyzing COS which is contained in a gas obtained by gasifying a carbon raw material, wherein a spent COS hydrolysis catalyst is immersed in an alkali solution for a prescribed amount of time; and then immersed in an acid solution for a prescribed amount of time.

3. A method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst by hydrolyzing COS which is contained in a gas obtained by gasifying a carbon raw material, wherein a spent COS hydrolysis catalyst is immersed in an acid solution for a prescribed amount of time; and then immersed in an alkali solution for a prescribed amount of time.

4. The method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst according to claim 1, wherein the immersion is performed in a prescribed heated state.

5. The method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst according to claim 2, wherein the immersion is performed in a prescribed heated state.

6. The method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst according to claim 3, wherein the immersion is performed in a prescribed heated state.

Description

BRIEF DESCRIPTION OF DRAWING(S)

(1) FIG. 1 illustrates the results of testing the catalyst recovery rate under various conditions.

(2) FIG. 2 illustrates the relationship between the change in temperature of a COS hydrolysis catalyst and the COS conversion rate.

DESCRIPTION OF EMBODIMENTS

(3) The following is a detailed description of preferred embodiments with reference to the attached drawings. Note that the invention is not limited by the embodiments, and when a plurality of embodiments are present, the invention is intended to include a configuration combining these embodiments.

(4) Embodiment 1.

(5) The method for regenerating a COS hydrolysis catalyst according to Embodiment 1 will be described.

(6) The method for regenerating a COS hydrolysis catalyst according to Embodiment 1 is a method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst by hydrolyzing COS which is contained in a gas obtained by gasifying a carbon raw material such as coal, for example, wherein a spent COS hydrolysis catalyst is immersed in an acid solution for a prescribed amount of time.

(7) The procedure of the method for regenerating a catalyst according to Embodiment 1 will be described hereinafter.

(8) (1) First, a COS hydrolysis catalyst with which a COS conversion device of a coal gasification power plant has been filled is extracted.

(9) (2) The dust content adhering to the extracted COS hydrolysis catalyst is removed by a gas spraying device such as an air blower.

(10) (3) Next, a prescribed amount of an acid solution is placed in an immersion vessel, and the air-blown COS hydrolysis catalyst is immersed in the acid solution. Here, the amount of the acid solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently hidden. More preferably, the amount is such that the volume ratio of the acid solution/COS hydrolysis catalyst is at least 3.

(11) As the acid solution, sulfuric acid (H.sub.2SO.sub.4), hydrochloric acid (HCl), nitric acid (HNO.sub.3), or the like with a concentration of at least 0.1 N and approximately 1 N can be used.

(12) In this chemical treatment, when the chemical solution is heated (for example, 60 to 80 C.), the removal efficiency of adhering sulfides or the like improves.

(13) (4) The substance is left and immersed for approximately 15 to 60 minutes in this immersed state.

(14) (5) The immersed COS hydrolysis catalyst is then immersed and water-washed in water (for example, ion-exchanged water) prepared in a separate vessel. Here, the amount of the water washing solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently hidden. More preferably, the amount is such that the volume ratio of water/COS hydrolysis catalyst is at least 3.

(15) (6) The substance is left and water-washed for approximately 15 to 60 minutes, for example, in this immersed state.

(16) (7) After water washing, the COS hydrolysis catalyst is taken out and dried after excess liquid in the catalyst is removed.

(17) Drying may be performed by means of natural drying or heat drying. Here, in the case of heat drying, the temperature is preferably from 80 C. to 200 C. and particularly preferably from 110 C. to 150 C.

(18) By performing chemical washing with an acid in this way, poisoning components adhering to a COS hydrolysis catalyst can be removed, which makes it possible to reuse the substance.

(19) Here, the dust removal by means of air blowing in step (2) can be omitted depending on the amount of dust adhering to the catalyst.

(20) Embodiment 2.

(21) The method for regenerating a COS hydrolysis catalyst according to Embodiment 2 will be described.

(22) The method for regenerating a COS hydrolysis catalyst according to Embodiment 2 is as method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst by hydrolyzing COS which is contained in a gas obtained by gasifying a carbon raw material such as coal, for example, wherein a spent COS hydrolysis catalyst is immersed in an alkali solution for a prescribed amount of time.

(23) The procedure of the method for regenerating a catalyst according to Embodiment 2 will be described hereinafter.

(24) (1) First, a catalyst with which a COS conversion device of a coal gasification power plant has been filled is extracted.

(25) (2) The dust content adhering to the extracted COS hydrolysis catalyst is removed by a gas spraying device such as an air blower.

(26) (3) Next, a prescribed amount of an alkali solution is placed in an immersion vessel, and the air-blown COS hydrolysis catalyst is immersed in the alkali solution. Here, the amount of the alkali solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently immersed. More preferably, the amount is such that the volume ratio of the alkali solution/COS hydrolysis catalyst is at least 3.

(27) As the alkali solution, sodium hydroxide (NaOH), ammonia water (NH.sub.4OH), sodium carbonate (Na.sub.2CO.sub.3), or the like with a concentration of at least 0.1 N and approximately 1 N can be used.

(28) In this chemical treatment, when the chemical solution is heated (for example, 60 to 80 C.), the removal efficiency of adhering sulfides or the like improves.

(29) (4) The substance is left and immersed for approximately 15 to 60 minutes, for example, in this immersed state.

(30) (5) The immersed COS hydrolysis catalyst is then immersed and water-washed in water (for example, ion-exchanged water) prepared in a separate vessel. Here, the amount of the water washing solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently hidden. More preferably, the amount is such that the volume ratio of water/COS hydrolysis catalyst is at least 3.

(31) (6) The substance is left and water-washed for approximately 15 to 60 minutes, for example, in this immersed state.

(32) (7) After water washing, the COS hydrolysis catalyst is taken out and dried after excess liquid in the catalyst is removed.

(33) Drying may be performed by means of natural drying or heat drying. In addition, the substance may also be calcined.

(34) By performing chemical washing with an alkali in this way, poisoning components adhering to a COS hydrolysis catalyst can be removed, which makes it possible to reuse the substance.

(35) Embodiment 3.

(36) The method for regenerating a COS hydrolysis catalyst according to Embodiment 3 will be described.

(37) The method for regenerating a COS hydrolysis catalyst according to Embodiment 3 is a method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst by hydrolyzing COS which is contained in a gas obtained by gasifying a carbon raw material such as coal, for example, wherein a spent COS hydrolysis catalyst is immersed in an alkali solution for a prescribed amount of time and then immersed in an acid solution for a prescribed amount of time.

(38) The procedure of the method for regenerating a catalyst according to Embodiment 3 will be described hereinafter.

(39) (1) First, a catalyst with which a COS conversion device of a coal gasification power plant has been filled is extracted.

(40) (2) The dust content adhering to the extracted COS hydrolysis catalyst is removed by a gas spraying device such as an air blower.

(41) (3) Next, a prescribed amount of an alkali solution is placed in an immersion vessel, and the air-blown COS hydrolysis catalyst is immersed in the alkali solution. Here, the amount of the alkali solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently hidden. More preferably, the amount is such that the volume ratio of the alkali solution/COS hydrolysis catalyst is at least 3.

(42) As the alkali solution, sodium hydroxide (NaOH), ammonia water (NH.sub.4OH), sodium carbonate (Na.sub.2CO.sub.3), or the like with a concentration of at least 0.1 N and approximately 1 N can be used.

(43) In this chemical treatment, when the chemical solution is heated (for example, 60 to 80 C.), the removal efficiency of adhering sulfides or the like improves.

(44) (4) The substance is left and immersed for approximately 15 to 60 minutes, for example, in this immersed state.

(45) (5) Next, a prescribed amount of an acid solution is placed in a separate immersion vessel, and the alkali-treated COS hydrolysis catalyst is immersed in the acid solution. Here, the amount of the acid solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently hidden. More preferably, the amount is such that the volume ratio of the acid solution/COS hydrolysis catalyst is at least 3.

(46) As the acid solution, sulfuric acid (H.sub.2SO.sub.4), hydrochloric acid (HCl) nitric acid (HNO.sub.3), or the like with a concentration of at least 0.1 N and approximately 1 N can be used.

(47) In this chemical treatment, when the chemical solution is heated (for example, 60 to 8020 C.), the removal efficiency of adhering sulfides or the like improves.

(48) (6) Further, the immersed COS hydrolysis catalyst is then immersed and water-washed in water (for example, ion-exchanged water) prepared in a separate vessel. Here, the amount of the water washing solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently hidden. More preferably, the amount is such that the volume ratio of water/COS hydrolysis catalyst is at least 3.

(49) (7) The substance is left and water-washed for approximately 15 to 60 minutes, for example, in this immersed state.

(50) (8) After water washing, the COS hydrolysis catalyst is taken out and dried after excess liquid in the catalyst is removed.

(51) Drying may be performed by means of natural drying or heat drying. In addition, the substance may also be calcined.

(52) By performing chemical washing with an alkali and then neutralizing the substance with an acid in this way, poisoning components adhering to a COS hydrolysis catalyst can be removed, which makes it possible to reuse the substance.

(53) Embodiment 4.

(54) The method for regenerating a COS hydrolysis catalyst according to Embodiment 4 will be described.

(55) Embodiment 4 is a method for regenerating a carbonyl sulfide (COS) hydrolysis catalyst by hydrolyzing COS which is contained in a gas obtained by gasifying a carbon raw material such as coal, for example, wherein a spent COS hydrolysis catalyst is immersed in an acid solution for a prescribed amount of time and then immersed in an alkali solution for a prescribed amount of time.

(56) The procedure of the method for regenerating a catalyst according to Embodiment 4 will be described hereinafter.

(57) (1) First, a catalyst with which a COS conversion device of a coal gasification power plant has been filled is extracted.

(58) (2) The dust content adhering to the extracted COS hydrolysis catalyst is removed by a gas spraying device such as an air blower.

(59) (3) Next, a prescribed amount of an acid solution is placed in an immersion vessel, and the air-blown COS hydrolysis catalyst is immersed in the acid solution. Here, the amount of the acid solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently hidden. More preferably, the amount is such that the volume ratio of the acid solution/COS hydrolysis catalyst is at least 3.

(60) As the acid solution, sulfuric acid (H.sub.2SO.sub.4), hydrochloric acid (HCl), nitric acid (HNO.sub.3), or the like with a concentration of at least 0.1 N and approximately 1 N can be used.

(61) In this chemical treatment, when the chemical solution is heated (for example, 60 to 80 C.), the removal efficiency of adhering sulfides or the like improves.

(62) (4) The substance is left and immersed for approximately 15 to 60 minutes, for example, in this immersed state.

(63) (5) Next, a prescribed amount of an alkali solution is placed in a separate immersion vessel, and the acid-treated COS hydrolysis catalyst is immersed in the alkali solution. Here, the amount of the alkali solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently hidden. More preferably, the amount is such that the volume ratio of the alkali solution/COS hydrolysis catalyst is at least 3.

(64) As the alkali solution, sodium hydroxide (NaOH), ammonia water (NH.sub.4OH), sodium carbonate (Na.sub.2CO.sub.3), or the like with a concentration of at least 0.1 N and approximately 1 N can be used.

(65) In this chemical treatment, when the chemical solution is heated (for example, 60 to 80 C.), the removal efficiency of adhering sulfides or the like improves.

(66) (6) Further, the immersed COS hydrolysis catalyst is then immersed and water-washed in water (for example, ion-exchanged water) prepared in a separate vessel. Here, the amount of the water washing solution is at least an amount which allows the COS hydrolysis catalyst to be sufficiently hidden. More preferably, the amount is such that the volume ratio of water/COS hydrolysis catalyst is at least 3.

(67) (7) The substance is left and water-washed for approximately 15 to 60 minutes, for example, in this immersed state.

(68) (8) After water washing, the COS hydrolysis catalyst is taken out and dried after excess liquid in the catalyst is removed.

(69) Drying may be performed by means of natural drying or heat drying. In addition, the substance may also be calcined.

(70) By performing chemical washing with an acid and then neutralizing the substance with an alkali in this way, poisoning components adhering to a COS hydrolysis catalyst can be removed, which makes it possible to reuse the substance.

(71) [Test Examples]

(72) Next, test examples illustrating the effect of the present invention will be described, but the present invention is not limited to these test examples.

(73) In Test Example 1, a spent COS hydrolysis catalyst is immersed in 1 N sulfuric acid for 30 minutes at room temperature and then washed with water for 30 minutes.

(74) In Test Example 2, a spent COS hydrolysis catalyst is immersed in 1 N sulfuric acid for 30 minutes while heating (60 C.) and then washed with water for 30 minutes.

(75) In Test Example 3, a spent COS hydrolysis catalyst is immersed in a 1 N sodium hydroxide aqueous solution for 30 minutes at room temperature, and the alkali-treated COS hydrolysis catalyst is then neutralized by means of immersion in 1 N sulfuric acid for 30 minutes at room temperature and then washed with water for 30 minutes.

(76) The COS hydrolysis catalyst used in these tests is a Ba/TiO.sub.2 honeycomb-type catalyst, and the temperature at which the COS conversion rate of the regenerated product was measured was 300 C.

(77) The recovery rate was determined from K/K.sub.0, Here, K is a reaction rate constant of the COS hydrolysis catalyst after regeneration, and K.sub.0 is a reaction rate constant of a fresh COS hydrolysis catalyst.

(78) In these tests, the substances prior to regeneration (immediately after use) were used as comparative examples.

(79) Using a fresh substance prior to use as a criterion of 1, the results of testing the catalyst recovery rate under various conditions are shown in FIG. 1.

(80) As illustrated in FIG. 1, in both acid treatment alone and treatment with both an alkali and an acid, an improvement in the catalyst recovery rate was confirmed in comparison to the catalysts prior to regeneration.

(81) In particular, in acid treatment, a greater improvement in the catalyst recovery rate was confirmed when treatment was performed while heating than when treatment was performed at room temperature.

(82) According to these tests, the recovery rate is at least 80%, so in contrast to conventional cases in which as catalyst component is newly re-supported with a chemical, it was possible to establish a method for inexpensively regenerating a COS hydrolysis catalyst.

(83) FIG. 2 illustrates the relationship between the change in temperature of a COS hydrolysis catalyst and the COS conversion rate.

(84) Using the regenerated COS hydrolysis catalyst of Test Example 1, the COS conversion rates at catalyst treatment temperatures (250 C., 300 C., and 350 C.) were measured and shown in FIG. 2.

(85) As illustrated in FIG. 2, it was confirmed that the substances of Test Example 1 (acid-treated products) always have a higher COS conversion rate than a catalyst prior to regeneration.

(86) In particular, it was confirmed that the acid-treated products have a higher COS conversion rate than a fresh product from a temperature range exceeding approximately 270 C.