KR20050071984A - Reformed zinc titanate sorbent composition and method thereof - Google Patents

Abstract

The present invention provides 25.0-45.0 wt% zinc oxide and 15.0-40.0 wt% titanium dioxide; 5.0-10.0 wt% of bentonite or pseudoboehmite; 1.0 to 5.0% by weight of alumina; Desulfurizer slurry by adding an organic binder, a dispersant and an antifoaming agent to 100% by weight of a mixture containing 7.0 to 15.0% by weight of NiO, 7.0 to 15.0% by weight of Co ₃ O ₄ , 1.0 to 5.0% by weight of MoO ₃ , and 7.0 to 15.0% by weight of FeOOH. The improved zinc titanate desulfurizing agent composition is characterized in that the granulated powder obtained by spray-drying the slurry is fired at 750 to 850 ° C. to effectively remove combustion gases such as sulfur compounds and to improve abrasion resistance and the like. to provide.

Description

Reformed Zinc Titanate Sorbent Composition and Method

The present invention relates to an improved zinc titanate desulfurizer composition containing zinc titanate as a main component and a large amount of transition metal oxide added as a catalyst, and a method of manufacturing the same. More specifically, the present invention is used as a main fuel in a coal gasification combined cycle system process. The present invention relates to an improved zinc titanate desulfurizing agent composition and a method for producing the same, which are effective for removing contaminants such as sulfur compounds generated in coal gas and having excellent characteristics such as wear resistance.

Desulfurization agents used to remove sulfur compounds from coal gas used in the coal gasification combined cycle system (IGCC) process are selectively pollutants of sulfur compounds such as H ₂ S, COS and CS ₂ when contacted with high temperature and high pressure coal gas. Because it absorbs and removes, it should be able to remove not only desulfurization but also combustion gas pollutants. In addition, the desulfurization agent absorbing sulfur compounds should be excellent in characteristics such as desulfurization regeneration reaction and abrasion resistance so that it can be repeatedly used after the regeneration process.

Currently, desulfurization agents include various metal oxides such as calcium-based, zinc-based and copper-based, but recently, iron ore, zinc ferrite and zinc titanate systems have been intensively studied due to the necessity of mass production. Among these desulfurization agents, zinc ferrite desulfurization agents are difficult to control due to high exothermic reactions and desulfurization agents deteriorate due to uneven generation of emission gas components and excessive reduction of ZnO and Fe ₂ O ₃ due to high reaction temperature or high reducible combustion gases. There is this.

In order to solve the problems of the prior art, the present invention is based on zinc titanate, which is known to have excellent reactivity and physical properties, and by adding a large amount of transition metal oxide as a catalyst for increasing activity, in a coal gasification combined cycle system process. In addition to sulfur compounds generated from coal gas used as the main fuel, it is effective for removing contaminants such as ammonium and tar, and has excellent abrasion resistance, etc., and can be used repeatedly for a long time even under high temperature and high pressure. It is an object to provide a desulfurizing agent composition and a method for producing the same.

As a means for achieving the above object, the present invention is an improved zinc titanate desulfurization agent containing zinc titanate as a main component and a large amount of transition metal oxide, etc. added as catalyst, zinc oxide 25.0-45.0 wt% and titanium dioxide 15.0-40.0 wt% %; 5.0-10.0 wt% of bentonite or pseudoboehmite; 1.0 to 5.0% by weight of alumina; Desulfurizer slurry by adding an organic binder, a dispersant and an antifoaming agent to 100% by weight of a mixture containing 7.0 to 15.0% by weight of NiO, 7.0 to 15.0% by weight of Co ₃ O ₄ , 1.0 to 5.0% by weight of MoO ₃ , and 7.0 to 15.0% by weight of FeOOH. The improved zinc titanate desulfurizing agent composition is characterized in that the granulated powder obtained by spray-drying the slurry is fired at 750 to 850 ° C. to effectively remove combustion gases such as sulfur compounds and to improve abrasion resistance and the like. to provide.

The organic binder in the above is not particularly limited and preferably includes at least one component selected from polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, and starch.

The dispersant in the above is not particularly limited and preferably includes one or more components selected from sodium carbonate, sodium silicate, sodium polyacrylate.

The dispersant is not particularly limited, and preferably includes one or more components selected from fluorocarbons, calcium sterates and aluminum sterates.

The present invention also provides a method for producing a desulfurization agent comprising a powder fired body containing zinc titanate as a main component.

The preparation method of the present invention comprises the first step of adding bentonite or pseudoboehmite 5.0 to 10.0% by weight as an inorganic binder to a mixture of water and a dispersant corresponding to the liquid ratio at the desired final slurry concentration;

Zinc oxide 25.0-45.0 wt% and titanium dioxide 15.0-40.0 wt%; 1.0 to 5.0% by weight of alumina; A second step of adding NiO 7.0 to 15.0 wt%, Co ₃ O ₄ 7.0 to 15.0 wt%, MoO ₃ 1.0 to 5.0 wt%, FeOOH 7.0 to 15.0 wt%, and then grinding and mixing;

A third step of slurrying by adding an organic binder and an antifoaming agent to the resultant of the second step; And

Spray drying and drying the slurry of the third step to provide a method for producing a desulfurizing agent comprising a fourth step of firing at 750 ~ 850 ℃.

The organic binder in the above is not particularly limited and preferably includes at least one component selected from polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, and starch.

The dispersant in the above is not particularly limited and preferably includes one or more components selected from sodium carbonate, sodium silicate, sodium polyacrylate.

The dispersant in the above is not particularly limited and preferably includes one or more components selected from fluorocarbons, calcium sterates and aluminum sterates.

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

The present invention is an improved zinc titanate desulfurization agent containing zinc titanate as a main component and a large amount of transition metal oxide, etc., as a catalyst for promoting activity, and zinc oxide (ZnO), which is a main raw material, has a very good desulfurization regeneration reactivity. Titanium dioxide (TiO ₂ ) is used as a carrier material. The amount of zinc oxide and titanium dioxide added is preferably in the range of 25.0 to 45.0% by weight and 15.0 to 40.0% by weight, and the composition ratio does not require any particular limitation, but most preferably the molar ratio of ZnO and TiO ₂ is 1.5. It is good to be. ZnO used for the embodiment of the present invention have an average particle diameter of 1.0㎛, TiO ₂ is used is an average particle diameter of 0.2㎛.

As a by-product, 1.0 to 5.0% by weight of Al ₂ O ₃ for enhancing strength and a transition metal oxide and a transition metal hydroxide which are catalysts are added in a large amount. As such a catalyst, NiO 7.0-15.0 wt%, Co ₃ O ₄ 7.0-15.0 wt%, MoO ₃ 1.0-5.0 wt% are used as the transition metal oxide, and FeOOH 7.0-15.0 wt% is used as the transition metal hydroxide. . The oxide and hydroxide can be optimally performed catalytic activity by adding in a large amount as described above. According to the person skilled in the art, other additional components such as Cu, W, and the like may be further added as required in addition to the oxide or hydroxide. In the embodiment of the present invention, the average particle diameters of Ni, Mo, and Co oxides are 0.8 μm, 4.0 μm, and 7.0 μm, respectively, and FeOOH has an amorphous hydroxide form.

In the desulfurizing agent composition of the present invention, bentonite or pseudoboehmite is used as the inorganic binder. These may be used alone or may be used in combination. Bentonite or pseudoboehmite is preferably added in an amount of 5.0 to 10.0% by weight. At this time, when added in less than 5.0% by weight, the degree of improvement of wear resistance is not large, and when it exceeds 10.0% by weight, there is almost no degree of additional characteristic improvement due to the excess. Also, within the range of 10.0% by weight, the wear resistance increased significantly as the amount of bentonite added increased.

The organic binder which can be used in the present invention is not particularly limited and preferably has at least one component selected from polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, starch. These organic binders are preferably added 1.0 to 3.0% by weight.

Dispersants usable in the present invention are not particularly limited and preferably include one or more components selected from fluorocarbons, calcium sterates and aluminum sterates. These dispersants are preferably 0.1 to 1.0% by weight.

When the content of the organic binder and the dispersant is out of the range, the dispersion stability of the slurry is lowered, and in particular, the wear resistance of the desulfurization agent is greatly reduced.

In the case of the antifoaming agent except the above components in the composition of the present invention, it is preferable that the antifoaming agent is added at the time of preparing the desulfurizing agent slurry to remove bubbles in the slurry, and is added at about 0.3% by weight.

The first step in the manufacturing process of the desulfurization agent of the present invention comprises adding 5.0 to 10.0% by weight of bentonite or pseudoboehmite as an inorganic binder to a mixture of water and a dispersant corresponding to a liquid ratio at a desired final slurry concentration. do. The mixing of water and dispersant is preferably by mixing these components in a polyethylene bottle and mixing with zirconia balls.

The second step in the manufacturing process of the desulfurization agent of the present invention is 25.0-45.0 wt% zinc oxide and 15.0-40.0 wt% titanium dioxide; 1.0 to 5.0% by weight of alumina; NiO 7.0-15.0 weight%, Co ₃ O ₄ 7.0-15.0 weight%, MoO ₃ 1.0-5.0 weight%, FeOOH 7.0-15.0 weight% are added, and it is the process of grind | mixing. Mixing of raw materials is performed by adjusting and adding zinc oxide and titanium dioxide, which are the main raw materials, to a predetermined molar ratio (preferably about 1.5) at regular intervals in order to improve the mixing and dispersing state in the slurry. Grinding and mixing for a predetermined time.

The third step of the manufacturing process of the desulfurization agent of the present invention is to add the organic binder and the antifoaming agent for strength and bubble removal after desulfurization agent granulation to the result of the second step. In the mixture comprising the agent and the antifoaming agent, it is preferably controlled by adding water such that the ratio of solid / liquid is 40/60 to 60/40.

The fourth step in the manufacturing process of the desulfurization agent of the present invention includes the process of spray-drying and granulating the slurry at 750 to 850 ° C. As a device for spray drying and granulation, a conventional spray dryer device may be used. Such devices are currently available in the form of various products.

The firing temperature is preferably 750 to 850 ° C. If the firing temperature is lower than 750 ° C, the powder of the desulfurization agent is not sufficiently sintered, and when observing their state in the wear resistance test, it is easy to observe the tendency of micronization by collision. Can be. In addition, when the firing temperature is higher than 850 ° C., there is a fear that the amount of abrasion resistance may increase, which is not preferable. At this time, the firing time is not particularly limited, and preferably 5 hours or more is sufficient.

When summarizing the above contents, the following presents the most preferred manufacturing example of the present invention.

35.6% by weight ZnO, 23.3% by weight TiO ₂ , 9.20% by weight NiO, 9.20% by weight Co ₃ O ₄ , 2.75% by weight MoO ₃ , 9.2% by weight FeOH and 2.75% by weight of Al ₂ O ₃ , inorganic binder 8.0 wt% of bentonite was added and 1.54 wt% of an organic binder, 0.5 wt% of a dispersant, and 0.3 wt% of an antifoaming agent were used to prepare a slurry for spray drying based on 100 wt% of the sum of the weights of the raw materials. In order to prepare a slurry so that the solid-to-liquid ratio is 40/60, the powder granulated by the spray drying method can be prepared, especially an improved zinc titanate desulfurization agent having excellent desulfurization regeneration reaction and abrasion resistance when calcined at 850 ° C. temperature. .

Hereinafter, the content of the present invention will be described in more detail with reference to preferred embodiments.

<Example 1>

The amount of ZnO is 183.8g and the amount of TiO ₂ is 123.8g, so that the molar ratio of ZnO and TiO ₂ used as the main raw material to prepare the improved zinc titanate-based desulfurization agent is 1.5. 47.5g, 47.5g of Co ₃ O ₄ , 14.25g of MoO ₃ , 47.5g of FeOOH and 14.25g of Al ₂ O ₃ , and 25.0g of bentonite as an inorganic binder were added. Based on 100% of the total weight of the raw materials, 1.18 to 1.36 wt% of polyvinyl alcohol solution, 0.30 to 0.40 wt% of dispersant, and 0.3 wt% of defoamer (trade name) as an antifoaming agent were added. A slurry for spray drying was prepared. At this time, the slurry was prepared by adding distilled water so that the solid to liquid ratio was constant at 40/60. Each slurry of the above composition was granulated using a spray dryer apparatus through a process as described in the present invention. The granulated desulfurization agent powder was calcined at 750 ° C., 800 ° C., and 850 ° C. for 5 hours, and then measured. The results are shown in Table 1 below.

<Table 1> Measurement result of the improved zinc titanate desulfurization agent

                characteristic      Sample Tap density (g / cm 3) particle Surface area (㎡ / g) Abrasion Resistance Loss (%) shape Size (μm)  ZTG40-E1 850 ℃ 1.18 rectangle 40.1 1.70 24.3  ZTG40-E1-1 (Organic binder = 1.27 wt% dispersant = 0.4 wt% addition firing temperature change) 750 ℃ 800 ℃ 850 ℃ 0.931.061.21 rectangle 50.746.340.9 12.912.710.8 2.96.565.3   ZTG40-E1-2 (Organic binder = 1.27wt% dispersant addition amount change 850 ℃) 0.300.350.40 1.251.241.21 rectangle 43.241.540.9 5.15.510.8 39.561.965.3

According to the measurement results, spherical desulfurization agents having a size of about 40-50 μm in all slurry compositions could be formed, and the same amount of organic binder was added to 1.27% by weight and 0.30% by weight, 0.35% by weight, and 0.40% by weight of the dispersant. When firing at 850 ° C. with different% by weight, the specific surface area was highest when 0.4 wt% of the dispersant was added, and the wear loss amount was low as 39.5% when 0.3 wt% of the dispersant was added.

In addition, when 0.40% by weight of dispersant was added and calcined at 750 to 850 ° C, the specific surface area was 10 m2 / g or more at all temperatures, and the desulfurization agent calcined at 750 ° C and 800 ° C had a very small amount of wear resistance loss. . However, SEM observation of the desulfurization agent particle state after the abrasion resistance test shows that the desulfurization agent particles are worn out more severely than when the wear loss is about 60 to 65%.

According to the results of the wear resistance test and SEM analysis of the above compositions, the desulfurization agent prepared by adding 1.27% by weight of an organic binder and 0.40% by weight of a dispersant in the slurry preparation was calcined at 850 ° C. after the abrasion resistance test. The state of the particles is also in the best state, and in this composition, the wear resistance was the best.

The reason for this result is that the amount of measured wear loss was small because the fine powder dropped by collision between desulfurization particles in the wear tester was scattered and remained in the glass container. In particular, SEM pictures of the desulfurizer particles when the wear loss was low at 2.9% and 6.5% showed that the desulfurizer particles were almost worn and mostly in powder form, and the worn powders were not scattered in the wear resistance test container. Since it remains, the measured wear resistance loss is very small. The desulfurization agent without bentonite had a 24% lower wear loss for similar reasons. That is, the above result can be obtained because the measurement of abrasion loss amount is calculated from the amount of initial sample to be put into the abrasion resistance test container and the amount of powder sample collected in the collection container attached to the abrasion resistance test container after completion of the test.

<Example 2>

As in Example 1, distilled water was added so as to have a solid-to-liquid ratio of 40/60, and bentonite, an inorganic binder, was increased from 5% to 8% in order to improve abrasion resistance. The remaining weight after subtracting bentonite weight 8% from 100% was added in the same weight ratio as in Example 1.

That is, the amount of ZnO in a molar ratio of ZnO and TiO ₂ is used as a main raw material such that 1.5 the amount of 178.0g, 116.4g TiO _2, NiO, yet additives to the catalyst is 46.0g, Co ₃ O ₄ was 46.0g, MoO ₃ 13.8 g of Fe, 46.0 g of FeOOH, 13.8 g of Al ₂ O ₃ , and 40.0 g of bentonite, an inorganic binder, were added. Based on 100% of the total weight of the raw materials, 1.44 to 1.64% by weight of polyvinyl alcohol solution as an organic binder, 0.45 to 0.55% by weight of cerasperse (trade name) as a dispersant, and 0.3% by weight of Defoamer (trade name) as an antifoaming agent. It was added to prepare a spray drying slurry.

Each slurry of the above composition was granulated using a spray dryer apparatus through the same process as in Example 1. The granulated desulfurizer powder was calcined at 850 ° C. for 5 hours and then its properties were measured. The results are shown in Table 2 below.

<Table 2> Measurement result of the improved zinc titanate desulfurization agent (bentonite content 8%)

               characteristic      Sample Tap density (g / cm 3) particle Surface area (㎡ / g) Wear loss (%) shape Size (μm)  ZTG40-E2-1 (organic binder = 1.36wt% dispersant addition amount change 850 ℃ baking) 0.45% 0.50% 0.55% 1.091.081.07 rectangle 51.740.252.6 2.871.742.25 48.839.642.7   ZTG40-E2-2 (dispersant = 0.5wt% addition amount of organic binder, 850 ° C firing) 1.44% 1.54% 1.64% 1.061.071.07 rectangle 53.555.150.6 5.662.023.79 47.130.230.7

According to the measurement results, in all cases, the size of the desulfurization agent was slightly different, but spherical desulfurization agent particles could be formed, and in the above composition, ZTG-E2-2 composition containing 1.54% of organic binder and 0.5% of dispersant was added. The wear resistance was 30.2% when calcined at 850 ° C., indicating that the wear resistance was significantly improved compared with the case where 5% of bentonite of Example 1 was added.

FIG. 1 shows SEM photographs of the desulfurization agent particles remaining in the container after the abrasion resistance test of the samples having the best abrasion resistance in Examples 1 and 2. From the results, the particle state in the case where the wear loss amount in Example 2 was found to be 30.2% was much better than the particle state after the abrasion resistance test in the case where the wear loss amount in Example 1 was 65.3%, and it was not scattered. The amount of fines remaining was found to be very small.

<Example 3>

The sample ZTG-E2-2 having the best wear resistance in the above example composition was subjected to continuous experiments for 5 hours in a high temperature dry desulfurization apparatus in which a high speed fluidized sulfidation reactor and a bubble fluidized bed regeneration reactor were connected. The total pressure of the process was maintained at 5 atm, the temperature of the sulfiding reactor was 600 ° C, and the regeneration reactor temperature was 700 ° C. Gas composition of the sulfide reactor is _{CO 18.1%, H 2 12.3%} , CO 2 8.9%, N 2 49.7%, was maintained at a _{H 2 O 10%, H 2} S 1%, the gas composition of the reproduction reactors O ₂ 10% , N ₂ was maintained at 90%. The flow rate of the high-speed fluidized bed reactor used as the sulfidation reactor was 2.0 m / s, and the flow rate of the bubble fluidized bed reactor used as the regenerated reactor was 0.045 m / s. The desulfurization agent used in this experiment was 7 kg.

Figure 2 shows the concentration curve of sulfur compounds in the gas discharged after purification in the desulfurization high-speed fluidized bed reactor. H ₂ S to give a gas composition to be injected to 10000 ppm by leakage after purification is the H ₂ S with an average 30 ppm, COS illustrates the performance of an average of 10 ppm and SO ₂ can not be detected at all. According to Figure 2 shows a desulfurization efficiency of more than 99.5% and the fuel gas thus purified is sent to the gas turbine.

Figure 3 shows the change of SO ₂ and O ₂ concentration in the gas from the regeneration reactor. Initial reaction conditions made the injected oxygen concentration 10% at the regeneration temperature of 600 degreeC. SO ₂ discharged from the combustion reaction was maintained at an average of 3% and O ₂ concentration was maintained at an average of 0.8%. The separated and highly concentrated SO ₂ is sent to the sulfur recovery process and made of salable sulfur.

The improved zinc titanate desulfurizing agent composition according to the present invention is effective for removing contaminants such as sulfur compounds generated from coal gas used as main fuel in the coal gasification combined cycle system process, and has excellent characteristics such as abrasion resistance, and thus under high temperature and high pressure. Repeated use over a long period of time is possible.

As described above, the present invention has been described with reference to the preferred embodiments, but those skilled in the art to which the present invention pertains vary the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be understood that modifications and changes can be made.

1 is an electron micrograph (SEM) of the desulfurization agent particles according to the present invention after the abrasion resistance test [(a) bentonite 5% by weight, (b) bentonite 8% by weight]

2 is a graph showing the concentration of sulfur compounds in the off-gas passing through the desulfurization agent in the desulfurization reactor using the desulfurization agent according to the present invention.

Figure 3 is a graph showing the concentration of SO ₂ and O ₂ in the exhaust gas in the regeneration reactor using a desulfurization agent according to the present invention

Claims (2)

In an improved zinc titanate desulfurization agent containing zinc titanate as a main component and a large amount of transition metal oxides added as a catalyst, zinc oxide 25.0-45.0 wt% and titanium dioxide 15.0-40.0 wt%; 5.0-10.0 wt% of bentonite or pseudoboehmite; 1.0 to 5.0% by weight of alumina; Desulfurizer slurry by adding an organic binder, a dispersant and an antifoaming agent to 100% by weight of a mixture containing 7.0 to 15.0% by weight of NiO, 7.0 to 15.0% by weight of Co ₃ O ₄ , 1.0 to 5.0% by weight of MoO ₃ , and 7.0 to 15.0% by weight of FeOOH. The obtained zinc titanate desulfurizing agent composition, which is obtained by calcining the granulated powder obtained by spray drying the slurry at 750 to 850 ° C. In the method for producing an improved zinc titanate desulfurization agent containing zinc titanate as a main component and a large amount of transition metal oxide, etc. added, A first step of adding bentonite or pseudoboehmite in an amount of 5.0 to 10.0% by weight as an inorganic binder to a mixture of water and a dispersant corresponding to a liquid ratio at a desired final slurry concentration; Zinc oxide 25.0-45.0 wt% and titanium dioxide 15.0-40.0 wt%; 1.0 to 5.0% by weight of alumina; A second step of adding NiO 7.0 to 15.0 wt%, Co ₃ O ₄ 7.0 to 15.0 wt%, MoO ₃ 1.0 to 5.0 wt%, FeOOH 7.0 to 15.0 wt%, and then grinding and mixing; A third step of slurrying by adding an organic binder and an antifoaming agent to the resultant of the second step; And Spray drying and drying the slurry of the third step, the method for producing a desulfurizing agent comprising a fourth step of firing at 750 ~ 850 ℃