Blast furnace gas fine desulfurization device and blast furnace gas fine desulfurization method

Abstract

According to the blast furnace gas fine desulfurization device and the blast furnace gas fine desulfurization method provided by the invention, the blast furnace gas fine desulfurization device is provided with the three absorption towers and the two conversion towers, so that on one hand, the content of harmful impurities such as chloride ions in gas in a catalytic section (the two conversion tower stages through which the blast furnace gas passes) is reduced; on the other hand, the H2S content in the coal gas at the catalytic section is reduced, so that the generation of elemental sulfur or sulfate is inhibited, the oxidation resistance and chlorination poisoning resistance of the hydrolysis catalysts in the two conversion towers are improved, and finally the poisoning problem of the hydrolysis catalysts is relieved.

Description

Technical Field

[0001] The invention relates to the technical field of coal gas desulfurization treatment, and in particular to a blast furnace coal gas fine desulfurization device and a blast furnace coal gas fine desulfurization method. Background Art

[0002] Blast furnace gas is a by-product of the blast furnace ironmaking process. In addition to CO2 (14-18% by mass), CO (24-28% by mass), H2 (1-2% by mass), and N2 (56-60% by mass), it also contains 50-200 mg / Nm 3 The sulfur-containing components of waste gas are mainly organic sulfur (COS and CS2, etc.) and inorganic sulfur (H2S), accounting for approximately 70% and 30% respectively. These sulfur-containing components are burned and converted into SO2 during subsequent use, polluting the environment.

[0003] The current mainstream blast furnace gas fine desulfurization scheme is COS hydrolysis conversion coupled with H2S removal. That is, COS, which is difficult to remove in the gas, is first converted into H2S, which is easy to remove, under the action of a hydrolysis catalyst, and then H2S is removed by activated carbon adsorption or alkaline solution absorption. In actual applications, there is a problem of easy poisoning and deactivation of the hydrolysis catalyst, resulting in a catalyst service life of less than half a year, which greatly increases the material cost. The technical stability has also been criticized, which seriously hinders the promotion and application of fine desulfurization technology. There are two main reasons for the deactivation of the hydrolysis catalyst: first, trace oxygen in the blast furnace gas oxidizes species such as H2S into elemental sulfur or even sulfate deposited on the catalyst surface, covering the active sites; second, the chloride ions in the blast furnace gas combine with the alkaline active sites on the catalyst surface, causing it to lose activity.

[0004] Therefore, it is urgent to develop a blast furnace gas fine desulfurization device and a blast furnace gas fine desulfurization method to solve the above technical problems. Summary of the invention

[0005] In view of this, the present application provides a blast furnace gas fine desulfurization device and a blast furnace gas fine desulfurization method to solve the technical problem that the hydrolysis catalyst in the existing blast furnace gas fine desulfurization device is easily poisoned and deactivated.

[0006] The object of the present invention is achieved through the following technical solutions: In order to achieve the above technical objectives, this application adopts the following technical solutions: The present invention provides a blast furnace gas fine desulfurization device, comprising a first absorption tower, a first conversion tower, a second absorption tower, a second conversion tower and a third absorption tower connected in sequence through pipelines; Among them, the first absorption tower is used to remove H2S and chloride ions in the blast furnace gas to be purified to obtain the first gas; the first conversion tower is used to convert half of the mass content of COS in the first gas into H2S to obtain the second gas; the second absorption tower is used to remove H2S in the second gas to obtain the third gas; the second conversion tower is used to convert COS in the third gas into H2S to obtain the fourth gas; the third absorption tower is used to completely absorb the H2S in the fourth gas to obtain the purified blast furnace gas.

[0007] Preferably, the first absorption tower, the second absorption tower and the third absorption tower are all filled with activated carbon.

[0008] Preferably, the volume space velocity of the first absorption tower, the second absorption tower and the third absorption tower is 1000-2000h -1 The reaction temperature is 40~120℃.

[0009] Preferably, the first conversion tower and the second conversion tower are both filled with a hydrolysis catalyst, and the hydrolysis catalyst is used to convert COS into H2S.

[0010] Preferably, the hydrolyzing agent comprises honeycomb γ-Al2O3.

[0011] Preferably, the volume space velocity of the first conversion tower and the second conversion tower is 1000-3000h -1 The reaction temperature is 50~120℃.

[0012] Preferably, the blast furnace gas fine desulfurization device has a total COS conversion rate of greater than or equal to 95% for the blast furnace gas to be purified, and a total sulfur removal rate of greater than or equal to 90%.

[0013] Accordingly, the present invention also provides a method for desulfurizing blast furnace gas using the blast furnace gas desulfurization device as described above, the method comprising the following steps: S10, providing a blast furnace gas fine desulfurization device, transporting the blast furnace gas to be purified to a first absorption tower for a first absorption treatment after gravity dust removal, and obtaining a first gas; S20, transporting the first coal gas to a first conversion tower for a first conversion treatment to obtain a second coal gas; S30, transporting the second coal gas to a second absorption tower for a second absorption treatment to obtain a third coal gas; S40, transporting the third coal gas to a second conversion tower for a second conversion treatment to obtain a fourth coal gas; S50, transporting the fourth coal gas to the third absorption tower for a third absorption treatment to obtain purified blast furnace gas.

[0014] Preferably, the first absorption tower, the second absorption tower and the third absorption tower are all filled with activated carbon; the volume space velocity of the first absorption tower, the second absorption tower and the third absorption tower is 1000-2000h -1 The reaction temperature is 40~120℃.

[0015] Preferably, the first conversion tower and the second conversion tower are both filled with a hydrolysis catalyst, which is used to convert COS into H2S; the volume space velocity of the first conversion tower and the second conversion tower is 1000-3000h -1 The reaction temperature is 50~120℃.

[0016] Beneficial effect: The present invention provides a blast furnace gas fine desulfurization device and a blast furnace gas fine desulfurization method, which first removes H2S and chloride ions in the blast furnace gas to be purified through a first absorption tower to obtain a first gas; then converts half of the mass content of COS in the first gas into H2S through a first conversion tower to obtain a second gas; then removes H2S in the second gas through a second absorption tower to obtain a third gas; then converts COS in the third gas into H2S through a second conversion tower to obtain a fourth gas; finally, the H2S in the fourth gas is completely absorbed by the third absorption tower to obtain purified blast furnace gas; the above-mentioned blast furnace gas fine desulfurization device is provided with three absorption towers and two conversion towers, on the one hand, reduces the content of harmful impurities such as chloride ions in the gas in the catalytic section (two conversion tower stages through which the blast furnace gas passes), and on the other hand, reduces the H2S content in the gas in the catalytic section, thereby inhibiting the generation of elemental sulfur or sulfate, thereby improving the oxidation resistance and chlorination poisoning resistance of the hydrolysis catalyst in the two conversion towers, and finally alleviating the poisoning problem of the hydrolysis catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the overall structure of a blast furnace gas fine desulfurization device provided in an embodiment of the present application; Figure 2 A method flow chart of a blast furnace gas fine desulfurization device provided in an embodiment of the present application; In the attached figure: 100 - blast furnace gas fine desulfurization device; 10 - first absorption tower; 20 - first conversion tower; 30 - second absorption tower; 40 - second conversion tower; 50 - third absorption tower. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] The technical problem that the hydrolysis catalyst in the existing blast furnace gas fine desulfurization device 100 is easily poisoned and deactivated is addressed. The blast furnace gas fine desulfurization device 100 is provided with three absorption towers and two conversion towers, which, on the one hand, reduces the content of harmful impurities such as chloride ions in the catalytic stage gas, and on the other hand, reduces the H2S content in the catalytic stage gas, thereby suppressing the generation of elemental sulfur or sulfate, thereby improving the oxidation resistance and chlorination poisoning resistance of the hydrolysis catalyst in the two conversion towers, and finally alleviating the poisoning problem of the hydrolysis catalyst.

[0020] See also Figure 1 , Figure 1 The overall structural schematic diagram of the blast furnace gas fine desulfurization device 100 provided in an embodiment of the present application; wherein the present invention provides a blast furnace gas fine desulfurization device 100, comprising a first absorption tower 10, a first conversion tower 20, a second absorption tower 30, a second conversion tower 40 and a third absorption tower 50 connected in sequence by pipelines; Among them, the first absorption tower 10 is used to remove H2S and chloride ions in the blast furnace gas to be purified to obtain the first gas; the first conversion tower 20 is used to convert half of the mass content of COS in the first gas into H2S to obtain the second gas; the second absorption tower 30 is used to remove H2S in the second gas to obtain the third gas; the second conversion tower 40 is used to convert COS in the third gas into H2S to obtain the fourth gas; the third absorption tower 50 is used to completely absorb the H2S in the fourth gas to obtain the purified blast furnace gas.

[0021] In the embodiment of the present invention, the first absorption tower 10, the second absorption tower 30 and the third absorption tower 50 are all filled with activated carbon; wherein the activated carbon has a highly developed pore structure, and this pore structure enables the activated carbon to have a huge specific surface area. For impurities such as hydrogen sulfide (H2S) and chloride ions in blast furnace gas, these impurity molecules can be adsorbed on the surface of the pores by physical adsorption. For example, H2S molecules can be adsorbed by van der Waals forces on the inner surface of the activated carbon pores, thereby being effectively removed from the blast furnace gas. When blast furnace gas containing chloride ions passes through activated carbon, the chloride ions will be captured by the pores of the activated carbon, and some chloride ions may also react chemically with some functional groups on the surface of the activated carbon, such as reacting with carbon-hydrogen groups on the surface of the activated carbon, further enhancing the removal effect of chloride ions.

[0022] In the embodiment of the present invention, the volume space velocity of the first absorption tower 10, the second absorption tower 30 and the third absorption tower 50 are all 1000-2000h -1 , preferably 1500h -1 The reaction temperatures of the first absorption tower 10, the second absorption tower 30 and the third absorption tower 50 are all 40-120°C, preferably 80°C.

[0023] Specifically, space velocity refers to the volume of gas passing through a unit volume of adsorbent per unit time. -1 This range means that a large amount of blast furnace gas can pass through the three absorption towers mentioned above every hour.

[0024] Specifically, the temperature range of 40~120℃ is more favorable for adsorption and desulfurization reactions. Taking the removal of hydrogen sulfide (H2S) as an example, within this temperature range, the adsorption and reaction kinetics of H2S molecules on the surface of activated carbon will be positively affected. When the temperature rises, the movement speed of gas molecules accelerates, and H2S molecules are more likely to diffuse into the pores of activated carbon, thereby improving the adsorption efficiency. For activated carbon in the absorption tower, the temperature range of 40~120℃ helps to maintain its good physical and chemical properties. Too low a temperature may cause the adsorption rate of gas molecules to be too slow, while too high a temperature may have an adverse effect on the structure of activated carbon, such as causing the destruction of the pore structure.

[0025] In the embodiment of the present invention, the first conversion tower 20 and the second conversion tower 40 are both filled with a hydrolysis catalyst, and the hydrolysis catalyst is used to convert COS into H2S; preferably, the hydrolysis agent includes honeycomb γ-Al2O3.

[0026] Specifically, when carbonyl sulfide (COS) in blast furnace gas comes into contact with a hydrolysis catalyst, a hydrolysis reaction occurs under the action of the active sites of the catalyst. Taking honeycomb γ-Al2O3 as an example, its surface has abundant active centers. COS molecules are adsorbed on the active sites of γ-Al2O3, and then react with water molecules to obtain H2S and CO2, thereby effectively removing H2S.

[0027] In the embodiment of the present invention, the volume space velocity of the first conversion tower 20 and the second conversion tower 40 are both 1000-3000h -1 , preferably 2000h -1 The reaction temperatures of the first conversion tower 20 and the second conversion tower 40 are both 50-120°C, preferably 80°C.

[0028] Specifically, for hydrolysis catalysts, the appropriate temperature can ensure the stable performance of their performance. If the temperature is too low, such as below 50°C, the reaction rate may be too slow and COS cannot be converted in a timely and effective manner. If the temperature is too high, such as above 120°C, it may have an adverse effect on the structure and performance of the catalyst, such as causing the catalyst to sinter or reduce active sites.

[0029] In an embodiment of the present invention, the blast furnace gas fine desulfurization device 100 has a total COS conversion rate of greater than or equal to 95% and a total sulfur removal rate of greater than or equal to 90% for the blast furnace gas to be purified. Among them, blast furnace gas is often used in various industrial production links later, such as gas turbine power generation, as chemical raw material gas, etc. The presence of COS and sulfur will have a corrosive effect on downstream equipment. For example, high-temperature components in gas turbines are prone to high-temperature corrosion in a gas environment containing sulfur and other impurities, resulting in reduced equipment performance and shortened service life. The total sulfur removal rate is greater than or equal to 90% and the COS total conversion rate is greater than or equal to 95%, which means that the content of these corrosive substances is greatly reduced, which can effectively reduce equipment maintenance costs, extend the safe and stable operation cycle of equipment, and ensure the smooth progress of the entire process.

[0030] See also Figure 2 The present invention also provides a method for fine desulfurization of blast furnace gas using the blast furnace gas fine desulfurization device 100 as described above, the method comprising the following steps: S10, providing a blast furnace gas fine desulfurization device 100, transporting the blast furnace gas to be purified to a first absorption tower 10 for a first absorption treatment after gravity dust removal, to obtain first gas; S20, transporting the first coal gas to the first conversion tower 20 for a first conversion treatment to obtain a second coal gas; S30, transporting the second coal gas to the second absorption tower 30 for a second absorption treatment to obtain a third coal gas; S40, transporting the third coal gas to the second conversion tower 40 for a second conversion treatment to obtain a fourth coal gas; S50, transporting the fourth coal gas to the third absorption tower 50 for a third absorption treatment to obtain purified blast furnace gas.

[0031] Specifically, the first absorption tower 10, the second absorption tower 30 and the third absorption tower 50 are all filled with activated carbon; the volume space velocity of the first absorption tower 10, the second absorption tower 30 and the third absorption tower 50 is 1000-2000h -1 The reaction temperature is 40~120℃.

[0032] Specifically, the first conversion tower 20 and the second conversion tower 40 are both filled with a hydrolysis catalyst, which is used to convert COS into H2S; the volume space velocity of the first conversion tower 20 and the second conversion tower 40 is 1000-3000h -1 The reaction temperature is 50~120℃.

[0033] Specifically, the specific working process of the blast furnace gas fine desulfurization device 100 provided in an embodiment of the present invention is as follows: first, the first absorption tower 10 absorbs and removes H2S (about 25% of the total sulfur) and chloride ions originally contained in the blast furnace gas to be purified; the first conversion tower 20 converts about half of the mass content of COS into H2S; the second absorption tower 30 absorbs the H2S converted in the first conversion tower 20; the second conversion tower 40 converts the other half of the mass content of COS into H2S; the third absorption tower 50 absorbs the H2S converted in the second conversion tower 40, and finally obtains the purified blast furnace gas.

[0034] The technical solution of the present invention is now further described in conjunction with specific embodiments.

[0035] Embodiment 1: See also Figure 1 , this embodiment 1 provides a blast furnace gas fine desulfurization device 100, providing a blast furnace gas fine desulfurization device 100, comprising a first absorption tower 10, a first conversion tower 20, a second absorption tower 30, a second conversion tower 40 and a third absorption tower 50 connected in sequence by pipelines; Among them, the first absorption tower 10 is used to remove H2S and chloride ions in the blast furnace gas to be purified to obtain the first gas; the first conversion tower 20 is used to convert half of the mass content of COS in the first gas into H2S to obtain the second gas; the second absorption tower 30 is used to remove H2S in the second gas to obtain the third gas; the second conversion tower 40 is used to convert COS in the third gas into H2S to obtain the fourth gas; the third absorption tower 50 is used to completely absorb the H2S in the fourth gas to obtain the purified blast furnace gas.

[0036] In this embodiment 1, the first absorption tower 10, the second absorption tower 30 and the third absorption tower 50 are filled with activated carbon, and the single tower volume space velocity is 1500h -1 , reaction temperature 80℃.

[0037] In this embodiment 1, the first conversion tower 20 and the second conversion tower 40 are filled with a hydrolysis catalyst, and the single tower volume space velocity is 2000h -1 , reaction temperature 80℃.

[0038] In this embodiment 1, the specific process of the blast furnace gas fine desulfurization method is as follows: The blast furnace gas to be purified flows through the first absorption tower 10, the first conversion tower 20, the second absorption tower 30, the second conversion tower 40 and the third absorption tower 50 in sequence to obtain the purified blast furnace gas. The first absorption tower 10 absorbs and removes the H2S (about 25% of the total sulfur) and chloride ions originally contained in the blast furnace gas to be purified to obtain the first gas; the first conversion tower 20 converts half of the COS in the first gas into H2S to obtain the second gas; the second absorption tower 30 absorbs the H2S in the second gas to obtain the third gas; the second conversion tower 40 converts the remaining COS in the third gas into H2S to obtain the fourth gas; the third absorption tower 50 absorbs the H2S in the fourth gas to obtain the purified blast furnace gas; wherein, the blast furnace gas fine desulfurization device 100 has a total COS conversion rate of greater than or equal to 95% and a total sulfur removal rate of greater than or equal to 90%.

[0039] Comparative Example 1: Comparative Example 1 provides a blast furnace gas fine desulfurization device 100, including a first absorption tower 10 and a first conversion tower 20 connected in sequence by pipelines, the first absorption tower 10 is used to remove H2S and chloride ions in the blast furnace gas to be purified to obtain a first gas; the first conversion tower 20 is used to convert COS in the first gas into H2S to obtain a second gas.

[0040] Specifically, the total sulfur content in the blast furnace gas to be purified is set to C0, of which COS accounts for 75% and H2S accounts for 25%; in the reaction of H2S oxidation to elemental sulfur or sulfate, the reaction order of H2S is 1, that is, under the same conditions, the oxidation amount is only proportional to the average concentration.

[0041] Under the above setting, the average H2S concentration of the catalytic section in Comparative Example 1 is 0.65C0, and the average H2S concentration of the catalytic section in Example 1 is 0.1875C0. Therefore, under the same conditions, the oxidation amount of H2S in the catalytic section in Example 1 is only 30% of the H2S in the catalytic section in Comparative Example 1, and the corresponding hydrolysis catalyst service life can be extended to more than 3 times.

[0042] In order to solve the problem that the hydrolysis catalyst is easily poisoned and deactivated, the blast furnace gas fine desulfurization device 100 provided by the present invention changes the one-turn and one-absorption into three-absorption and two-turn operation. On the one hand, it reduces the content of harmful impurities such as chloride ions in the catalytic stage gas, and on the other hand, it reduces the H2S content in the catalytic stage gas. The formation of elemental sulfur or sulfate is inhibited, thereby improving the catalyst's resistance to oxidation and chlorination poisoning and alleviating the catalyst poisoning problem.

[0043] In summary, different from the prior art, the present invention provides a blast furnace gas fine desulfurization device 100 and a blast furnace gas fine desulfurization method, which first removes H2S and chloride ions in the blast furnace gas to be purified through a first absorption tower 10 to obtain a first gas; then, half of the COS by mass in the first gas is converted into H2S through a first conversion tower 20 to obtain a second gas; then, the H2S in the second gas is removed through a second absorption tower 30 to obtain a third gas; then, the COS in the third gas is converted into H2S through a second conversion tower 40 to obtain a fourth gas. gas; finally, the H2S in the fourth gas is completely absorbed by the third absorption tower 50 to obtain purified blast furnace gas; the above-mentioned blast furnace gas fine desulfurization device 100 is provided with three absorption towers and two conversion towers, on the one hand, reduces the content of harmful impurities such as chloride ions in the gas in the catalytic section (the two conversion tower stages through which the blast furnace gas passes), and on the other hand, reduces the H2S content in the gas in the catalytic section, thereby inhibiting the formation of elemental sulfur or sulfate, thereby improving the oxidation resistance and chlorination poisoning resistance of the hydrolysis catalyst in the two conversion towers, and finally alleviating the poisoning problem of the hydrolysis catalyst.

[0044] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A blast furnace gas fine desulfurization device, characterized in that: It includes a first absorption tower, a first conversion tower, a second absorption tower, a second conversion tower and a third absorption tower which are connected in sequence through pipelines; Among them, the first absorption tower is used to remove H2S and chloride ions in the blast furnace gas to be purified to obtain the first gas; the first conversion tower is used to convert half of the mass content of COS in the first gas into H2S to obtain the second gas; the second absorption tower is used to remove H2S in the second gas to obtain the third gas; the second conversion tower is used to convert COS in the third gas into H2S to obtain the fourth gas; the third absorption tower is used to completely absorb the H2S in the fourth gas to obtain the purified blast furnace gas.

2. The blast furnace gas fine desulfurization device according to claim 1, characterized in that: The first absorption tower, the second absorption tower and the third absorption tower are all filled with activated carbon.

3. The blast furnace gas fine desulfurization device according to claim 2, characterized in that: The volume space velocity of the first absorption tower, the second absorption tower and the third absorption tower is 1000-2000h -1 The reaction temperature is 40~120℃.

4. The blast furnace gas fine desulfurization device according to claim 1, characterized in that: The first conversion tower and the second conversion tower are both filled with a hydrolysis catalyst, and the hydrolysis catalyst is used to convert COS into H2S.

5. The blast furnace gas fine desulfurization device according to claim 4, characterized in that: The hydrolyzing agent includes honeycomb γ-Al2O3.

6. The blast furnace gas fine desulfurization device according to claim 4, characterized in that: The volume space velocity of the first conversion tower and the second conversion tower is 1000-3000h -1 The reaction temperature is 50~120℃.

7. The blast furnace gas fine desulfurization device according to claim 1, characterized in that: The blast furnace gas fine desulfurization device has a total COS conversion rate of greater than or equal to 95% and a total sulfur removal rate of greater than or equal to 90% for the blast furnace gas to be purified.

8. A method for fine desulfurization of blast furnace gas using the blast furnace gas fine desulfurization device according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: S10, providing the blast furnace gas fine desulfurization device, and transporting the blast furnace gas to be purified to the first absorption tower for a first absorption treatment after gravity dust removal, to obtain the first gas; S20, transporting the first coal gas to the first conversion tower for a first conversion treatment to obtain the second coal gas; S30, transporting the second coal gas to the second absorption tower for a second absorption treatment to obtain the third coal gas; S40, transporting the third coal gas to the second conversion tower for a second conversion treatment to obtain the fourth coal gas; S50, conveying the fourth coal gas to the third absorption tower for a third absorption treatment to obtain the purified blast furnace gas.

9. The method for fine desulfurization of blast furnace gas according to claim 8, characterized in that: The first absorption tower, the second absorption tower and the third absorption tower are all filled with activated carbon; the volume space velocity of the first absorption tower, the second absorption tower and the third absorption tower is 1000-2000h -1 , the reaction temperature is 40-120°C.

10. The method for fine desulfurization of blast furnace gas according to claim 8, characterized in that: The first conversion tower and the second conversion tower are both filled with a hydrolysis catalyst, which is used to convert COS into H2S; the volume space velocity of the first conversion tower and the second conversion tower is 1000-3000h -1 , the reaction temperature is 50-120°C.

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