A chlorine-fixing agent, its preparation method and application

Abstract

This invention provides a chlorine-fixing agent, its preparation method, and its application. The chlorine-fixing agent comprises: 25-70 parts by weight of an active component, 1-20 parts by weight of an auxiliary agent, 10-30 parts by weight of a carrier, 15-25 parts by weight of a binder component, and 1-5 parts by weight of rare earth oxides; the auxiliary agent includes at least one of titanium dioxide, iron oxide, and silicon dioxide. The chlorine-fixing agent, especially under high-temperature conditions, exhibits a high chlorine-fixing rate, is not easily decomposed or caking, and alleviates chlorine corrosion in industrial gasification furnaces.

Description

Technical Field

[0001] This invention belongs to the field of flue gas purification and treatment technology, specifically relating to a solid chlorine agent that removes HCl gas under high temperature conditions, its preparation method, and its application. Background Technology

[0002] China is a country rich in coal, poor in oil, and with limited natural gas. Coal resources are abundant and account for the largest proportion of China's primary energy consumption. Methanol production primarily uses coal and natural gas as raw materials, and China's energy structure dictates that industrial production mainly uses coal to produce methanol. In the coal-to-methanol process, chlorides in the coal evaporate and transform in a pressurized coal gasifier. A small portion of the reaction products remain in the slag, while the majority precipitates as HCl and enters the crude coal gas. This HCl, along with other acidic gases, causes severe corrosion to the gasifier and subsequent equipment. This leads to numerous technical problems during coal utilization, and chlorine emissions from coal combustion have become one of the main sources of atmospheric chlorine pollution.

[0003] If the chlorine content in the raw coal for gasification is high, the resulting high-temperature gas will inevitably have a high chlorine content. In light of this, to mitigate gasifier corrosion caused by the coal gasification process, chemical adsorption technology can be used to solidify and remove the HCl produced during high-temperature coal gasification. This is achieved by adding a chlorine-fixing agent to the raw coal, causing some chlorine-containing compounds to react chemically with the agent during coal combustion and gasification, thereby fixing some chlorine in the slag and reducing the HCl content in the crude gas. This approach mitigates the corrosion of the gasifier and subsequent equipment by the corrosive HCl formed during the combustion and gasification of high-chlorine coal at its source, extends equipment operating cycles, reduces the toxicity to shift catalysts and synthesis catalysts, improves the company's economic efficiency, and removes obstacles to the clean utilization of high-chlorine coal.

[0004] CN111617624A discloses a dechlorination agent, its preparation method, and its uses. The main raw materials of the dechlorination agent include alkaline earth metal compounds, alumina powder, molecular sieves, minerals, and composite molding aids such as zirconium oxide particles and resin powder. The dechlorination agent achieves a chlorine penetration capacity of over 45% at 50°C.

[0005] CN1334139A discloses a high-temperature gas dechlorination agent and its preparation method. This dechlorination agent uses natural sepiolite, alkali metals, and alkaline earth metal compounds as active components. Sepiolite serves as both the active component and the dechlorination agent carrier. A certain amount of inorganic or organic binder and pore-expanding agent are added, and the mixture is calcined at 350–800°C after molding. At a reaction temperature of 650°C, the HCl content in the high-temperature gas can be reduced to below 0.5 ppm, with a chlorine penetration capacity of 36%.

[0006] CN110624382A discloses a high-temperature flue gas dechlorination agent and its preparation method. The dechlorination agent uses at least one of calcium hydroxide, calcium carbonate, magnesium carbonate, calcium oxide, or magnesium oxide as the active component, and at least one of carbon powder, starch, attapulgite, or sucrose powder as the pore-forming agent; at least one of sodium carboxymethyl cellulose, silica sol, or water as the binder. It is then shaped by adding alkali-modified aluminum-based powder and calcined at 300–600°C. This dechlorination agent can be used at high temperatures up to 500°C without caking or strength reduction after use, and exhibits high dechlorination activity and precision.

[0007] CN103041769A discloses a high-temperature dechlorination agent and its preparation method. The dechlorination agent uses one or more of calcium nitrate, calcium hydroxide, magnesium nitrate, copper nitrate, and zinc nitrate as active components, aluminum nitrate or aluminum hydroxide as carrier and additives, and adds a certain amount of clay. The dechlorination agent prepared can efficiently and deeply remove chlorine-containing gases from flue gas in the temperature range of 450 to 750°C, with a chlorine penetration capacity of more than 60%.

[0008] The aforementioned dechlorinating agents are all focused on removing chlorine-containing gases from flue gas. Most of these agents operate at temperatures between 100 and 800°C, making them unsuitable for higher-temperature dechlorination processes. Ordinary dechlorinating agents used in coal chemical processes are prone to caking at high temperatures, and the reaction products exhibit poor high-temperature stability and are susceptible to high-temperature hydrolysis, resulting in a removal rate of less than 20%. Furthermore, their chlorine-fixing activity and precision are low, and there are few reports or methods for preparing chlorine-fixing agents applicable to coal combustion and gasification processes. Therefore, it is necessary to develop high-temperature chlorine-fixing agents that operate under high-temperature conditions, referencing the operating conditions of industrial gasifiers, to ensure the long-term stable operation of enterprise facilities. Summary of the Invention

[0009] To address the problems of existing dechlorination agents in high-temperature coal chemical applications, such as easy caking, low dechlorination activity and precision, and high-temperature decomposition of reaction products, the present invention aims to provide a chlorination-fixing agent, its preparation method, and its application. This chlorination-fixing agent, especially under high-temperature conditions, exhibits a high chlorination fixation rate, is not easily decomposed or caking, and alleviates chlorine corrosion in industrial gasifiers.

[0010] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0011] The first aspect of the present invention provides a chlorine-fixing agent, the chlorine-fixing agent comprising: 25 to 70 parts by weight of an active component, 1 to 20 parts by weight of an auxiliary agent, 10 to 30 parts by weight of a carrier, 15 to 25 parts by weight of an adhesive component, and 1 to 5 parts by weight of rare earth oxides.

[0012] The additives include at least one of titanium dioxide, iron oxide, and silicon dioxide; preferably at least one of iron oxide and silicon dioxide.

[0013] According to the present invention, preferably, the additives include silicon dioxide and iron oxide.

[0014] According to the present invention, the mass ratio of silicon dioxide to iron oxide is further 0.2:1 to 5:1, preferably 0.5:1 to 5:1. Examples of the mass ratio of silicon dioxide to iron oxide include, but are not limited to, the following values: 0.55:1, 0.6:1, 1:1, 2:1, 3:1, 3.5:1, 4:1, and 4.5:1. Silicon dioxide and iron oxide have a synergistic effect, and the solid chloride agent formed in combination with the active components can effectively remove chlorides at high temperatures.

[0015] According to the present invention, the active component includes at least one of calcium oxide, sodium oxide, potassium oxide, and strontium oxide.

[0016] According to the present invention, the mass ratio of the active component to the adjuvant is 1.25:1 to 20:1, preferably 3:1 to 12:1. Examples of the mass ratio of the active component to the adjuvant include, but are not limited to, the following values: 4:1, 5:1, 6:1, 7:1, 8:1, 8.5:1, 9:1, 9.5:1, 10:1, 10.5:1, 11:1, and 11.5:1.

[0017] According to the present invention, the carrier comprises aluminum oxide; the rare earth oxide comprises at least one of cerium oxide and lanthanum oxide.

[0018] According to the present invention, the chlorine-fixing agent is a high-temperature chlorine-fixing agent; the application temperature of the chlorine-fixing agent is 600-1100℃, preferably 700-1100℃, more preferably 800-1100℃, and even more preferably 900-1100℃.

[0019] A second aspect of the present invention provides a method for preparing the above-mentioned solid chlorine agent, comprising the following steps:

[0020] (1) After grinding and mixing the active component source and the auxiliary agent evenly, react with an alkaline solution to separate the solid, wash, dry and calcine to obtain the composite active component;

[0021] (2) Mix the pore-expanding agent, carrier precursor, binder and the composite active component obtained in step (1) evenly; add water, knead into shape, dry to obtain the molded product;

[0022] (3) The molded material obtained in step (2) is immersed in a rare earth metal salt solution, and then dried and calcined to obtain a solid chlorine agent.

[0023] According to the present invention, the active component source in step (1) includes at least one of calcium hydroxide, calcium carbonate, calcium acetate, sodium carbonate, potassium carbonate, and strontium carbonate; the alkaline solution in step (1) is ammonia water.

[0024] According to the present invention, the molar concentration of the alkaline solution in step (1) is further 2 to 6 mol / L. The amount of alkaline solution added is adjusted to control the solid-liquid mass ratio in the reaction liquid in the reactor to be 1:5 to 1:15, preferably 1:5 to 1:9.

[0025] According to the present invention, the grinding in step (1) is preferably carried out in a vibratory grinding mill; the particle size after grinding is 200-500 mesh; the reaction is carried out under stirring at 50-100 rpm; the reaction temperature is 65-98°C and the time is 6-20 h; the separation method of the solid can be selected from conventional solid-liquid separation methods as needed, such as filtration, vacuum filtration, preferably vacuum filtration; the washing degree is to wash to neutral; the drying conditions are a temperature of 100-150°C and a time of 4-12 h; the calcination conditions are a temperature of 800-900°C and a time of 2-8 h.

[0026] According to the present invention, in step (2), the pore-expanding agent, carrier precursor, and binder are ground and then mixed with the composite active component, and ground to 200-500 mesh; the amount of water added in step (2) is 10%-50% of the mass of the pore-expanding agent, carrier precursor, binder, and composite active component in step (2); the water is preferably deionized water. The amount of pore-expanding agent added is 1%-5% of the mass of the solid chlorine agent. The pore-expanding agent includes ammonium bicarbonate; the carrier precursor includes boehmite; the binder includes kaolin.

[0027] According to the present invention, the kneading and shaping in step (2) can be selected as needed, preferably kneading in a kneader at a speed of 15-40 r / min for 0.5-2 h until a paste is formed; the paste is then extruded in a screw extruder into strips with a diameter of 1-2 mm. The drying conditions are: temperature 100-120°C, time 4-24 h.

[0028] According to the present invention, the rare earth metal salt in step (3) is preferably a rare earth nitrate. The impregnation is an equal-volume impregnation. The drying conditions are: temperature 100-150℃, time 3-12h; the drying equipment is an oven. The calcination conditions are: temperature 450-700℃, time 2-10h.

[0029] The third aspect of this invention provides the application of the above-mentioned solid chlorine agent in coal chemical industry at high temperatures.

[0030] The application conditions are: temperature 600-1100℃, preferably 700-1100℃, even more preferably 800-1100℃, and even more preferably 900-1100℃.

[0031] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0032] (1) In this invention, the chlorine-fixing agent comprises: 25-70 parts by weight of an active component (at least one of calcium oxide, sodium oxide, potassium oxide, and strontium oxide), 1-20 parts by weight of an auxiliary agent, 10-30 parts by weight of a carrier, 15-25 parts by weight of a binder component, and 1-5 parts by weight of rare earth oxides; the auxiliary agent comprises at least one of titanium dioxide, iron oxide, and silicon dioxide, preferably at least one of iron oxide and silicon dioxide. Within a specific content range, in the composition of the chlorine-fixing agent of this invention, at least one of calcium oxide, sodium oxide, potassium oxide, and strontium oxide forms excellent compatibility with iron oxide and silicon dioxide, generating a composite phase that is difficult to decompose under high temperature conditions, which can effectively alleviate and prevent the hydrolysis or decomposition of chlorine-containing phases. When the chlorine-fixing agent of this invention is applied in coal chemical industry at high temperature, it has a high chlorine-fixing rate, is not easily decomposed or caking, and alleviates chlorine corrosion in industrial gasifiers.

[0033] (2) In the present invention, the preparation method is to first mix a certain amount of pretreated active components, additives, molding aids and carriers, then knead them into a paste, then extrude and mold them, dry them and load them with a small amount of rare earth elements, and finally calcine them to obtain the product, which can effectively remove chlorides under high temperature conditions.

[0034] (3) In this invention, the chlorine-fixing agent prepared by this invention has a high chlorine-fixing rate in the high-temperature range (600-1100℃), which can delay the high-temperature sintering of the chlorine-fixing reactants, and the generated chlorine-containing thermally stable salt is not easily decomposed under high-temperature conditions, which can effectively alleviate chlorine corrosion in industrial gasification furnaces. At 1100℃, the chlorine-fixing rate can be as high as 63% or more. Detailed Implementation

[0035] The following embodiments are a further detailed description of the present invention.

[0036] In this invention, pore volume and specific surface area were measured using an ASAP 2420 low-temperature nitrogen adsorption instrument.

[0037] In this invention, the particle strength is measured using a VCS universal packing strength tester.

[0038] In this invention, the chlorine content in the absorption liquid is determined using an RPP-200C salt content analyzer. The method for testing the chlorine content is as follows: the chlorine gas released after burning coal samples without added chlorine-fixing agent and coal samples with added chlorine-fixing agent is absorbed by an absorption bottle, and the chlorine content in the gas is measured.

[0039] The solid chlorine content is:

[0040]

[0041] In the formula: η—chlorine fixation rate, %;

[0042] C0—Chlorine content measured after chlorine precipitation in coal samples without added chlorine-fixing agent, in μg / g;

[0043] C — Chlorine content of coal sample after chlorine precipitation with added chlorine-fixing agent, μg / g.

[0044] Example 1:

[0045] (1) Weigh out 23 parts of calcium hydroxide (calcium oxide), 21 parts of sodium carbonate (sodium oxide), 20 parts of strontium carbonate (strontium oxide), 13 parts of silicon dioxide, and 6 parts of iron oxide. Grind them evenly in a vibratory grinder to a fineness of 200 mesh. Mix the sieved material with a 2 mol / L ammonia solution and add it to a reaction vessel for reaction. Adjust the amount of alkali solution added to control the solid-liquid mass ratio in the reaction vessel to be 1:5. Heat the mixture uniformly at 65°C for 6 hours; the reaction is carried out with stirring at 50 rpm. After the reaction is complete, vacuum filter the mixture. Wash the filter cake with distilled water until neutral, and then dry it at 120°C for 4 hours to obtain a homogeneous solid mixture. Calcine the obtained solid mixture at 800°C for 3 hours to obtain the composite active component.

[0046] (2) Grind ammonium bicarbonate (3% of the solid chlorine agent mass), kaolin (equivalent to 18 parts of the binder component), and boehmite (equivalent to 15 parts of alumina) to a fineness of 200 mesh or higher. Take the sieved mixed powder and mix it evenly with the composite active component obtained in step (1). Then add deionized water, the amount of which is 30% of the mass of the pore expander, carrier precursor, binder, and composite active component. Knead the mixture in a kneader at a speed of 20 r / min for 1 h until the material is in paste form. Extrude the paste into a shape using a 2 mm round die in a twin-screw extruder and dry it in a 100℃ oven for 6 h to obtain the molded product.

[0047] (3) The molded material obtained in step (2) is immersed in a 0.14 mol / L cerium nitrate aqueous solution, dried at 120℃ for 8 h, and then calcined at 600℃ for 6 h to obtain the required high-temperature chlorination agent A. The composition of the chlorination agent is shown in Table 1, and the effect is shown in Table 2.

[0048] Example 2:

[0049] (1) Calcium hydroxide (equivalent to 18 parts calcium oxide), potassium carbonate (equivalent to 20 parts potassium oxide), silicon dioxide, and ferric oxide were ground evenly in a vibratory grinder to a fineness of 300 mesh. The sieved material was mixed with a 4 mol / L ammonia solution and added to a reaction vessel for reaction. The amount of alkali added was adjusted to control the solid-liquid mass ratio in the reaction vessel to be 1:8. The mixture was heated uniformly at 80°C for 10 hours, and stirred at 80 rpm. After the reaction was completed, the mixture was vacuum filtered, the filter cake was washed with distilled water until neutral, and then dried at 120°C for 4 hours to obtain a homogeneous solid mixture. The obtained solid mixture was calcined at 800°C for 4 hours to obtain the composite active component.

[0050] (2) Grind ammonium bicarbonate (4% by mass of the solid chlorine agent), kaolin (equivalent to 22 parts by mass of the binder component), and boehmite (equivalent to 17 parts by mass of alumina) to 300 mesh. Take the sieved mixed powder and mix it evenly with the composite active component obtained in step (1). Then add deionized water, the amount of which is 40% of the mass of the pore expander, carrier precursor, binder, and composite active component. Knead in a kneader at a speed of 35 r / min for 0.5 h until the material is in paste form. Take the above paste material and extrude it into shape using a twin-screw extruder with a 2 mm round die. Dry it in a 100℃ oven for 8 h to obtain the molded product.

[0051] (3) The molded product obtained in step (2) is immersed in a 0.20 mol / L lanthanum nitrate aqueous solution, dried at 120℃ for 8 h, and then calcined at 500℃ for 5 h to obtain the required high-temperature chlorination agent B. The composition of the chlorination agent is shown in Table 1, and the effect is shown in Table 2.

[0052] Example 3:

[0053] (1) Calcium hydroxide (equivalent to 18 parts calcium oxide), potassium carbonate (equivalent to 20 parts potassium oxide), silicon dioxide, and iron oxide were ground evenly in a vibratory grinder to a fineness of 300 mesh. The sieved material was mixed with a 4 mol / L ammonia solution and added to a reaction vessel for reaction. The amount of alkali added was adjusted to control the solid-liquid mass ratio in the reaction vessel to be 1:8. The mixture was heated uniformly at 80°C for 10 hours, and the reaction was carried out with stirring at 80 rpm. After the reaction was completed, the mixture was vacuum filtered, the filter cake was washed with distilled water until neutral, and then dried at 120°C for 4 hours to obtain a homogeneous solid mixture. The obtained solid mixture was calcined at 800°C for 4 hours to obtain the composite active component.

[0054] (2) Grind ammonium bicarbonate (4% by mass of the solid chlorine agent), kaolin (equivalent to 22 parts by mass of the binder component), and boehmite (equivalent to 17 parts by mass of alumina) to 300 mesh. Take the sieved mixed powder and mix it evenly with the composite active component obtained in step (1). Then add deionized water, the amount of which is 40% of the mass of the pore expander, carrier precursor, binder, and composite active component. Knead in a kneader at a speed of 35 r / min for 0.5 h until the material is in paste form. Take the above paste material and extrude it into shape using a twin-screw extruder with a 2 mm round die. Dry it in a 100℃ oven for 8 h to obtain the molded product.

[0055] (3) The molded product obtained in step (2) was immersed in a 0.20 mol / L lanthanum nitrate aqueous solution, dried at 120°C for 8 h, and then calcined at 500°C for 5 h to obtain the desired high-temperature chlorine-fixing agent C. The composition of the chlorine-fixing agent is shown in Table 1, and the effect is shown in Table 2.

[0056] Example 4:

[0057] (1) Calcium hydroxide (equivalent to 18 parts calcium oxide), potassium carbonate (equivalent to 20 parts potassium oxide), and silicon dioxide (equivalent to 9 parts) were ground evenly in a vibratory grinder to a fineness of 300 mesh. The sieved material was mixed with a 4 mol / L ammonia solution and added to a reaction vessel for reaction. The amount of alkali solution added was adjusted to control the solid-liquid mass ratio in the reaction vessel to be 1:8. The reaction was uniformly heated to 80°C for 10 hours, and the reaction was carried out under stirring at 80 rpm. After the reaction was completed, the mixture was vacuum filtered, the filter cake was washed with distilled water until neutral, and then dried at 120°C for 4 hours to obtain a homogeneous solid mixture. The obtained solid mixture was calcined at 800°C for 4 hours to obtain the composite active component.

[0058] (2) Grind ammonium bicarbonate (4% by mass of the solid chlorine agent), kaolin (equivalent to 22 parts by mass of the binder component), and boehmite (equivalent to 17 parts by mass of alumina) to 300 mesh. Take the sieved mixed powder and mix it evenly with the composite active component obtained in step (1). Then add deionized water, the amount of which is 40% of the mass of the pore expander, carrier precursor, binder, and composite active component. Knead in a kneader at a speed of 35 r / min for 0.5 h until the material is in paste form. Take the above paste material and extrude it into shape using a twin-screw extruder with a 2 mm round die. Dry it in a 100℃ oven for 8 h to obtain the molded product.

[0059] (3) The molded product obtained in step (2) was immersed in a 0.20 mol / L lanthanum nitrate aqueous solution, dried at 120°C for 8 h, and then calcined at 500°C for 5 h to obtain the required high-temperature chlorine-fixing agent D. The composition of the chlorine-fixing agent is shown in Table 1, and the effect is shown in Table 2.

[0060] Example 5:

[0061] (1) Calcium hydroxide (equivalent to 18 parts calcium oxide), potassium carbonate (equivalent to 20 parts potassium oxide), and titanium dioxide (equivalent to 9 parts) were ground evenly in a vibratory grinder to a fineness of 300 mesh. The sieved material was mixed with a 4 mol / L ammonia solution and added to a reaction vessel for reaction. The amount of alkali added was adjusted to control the solid-liquid mass ratio in the reaction vessel to be 1:8. The mixture was heated uniformly at 80°C for 10 hours, and the reaction was carried out with stirring at 80 rpm. After the reaction was completed, the mixture was vacuum filtered, the filter cake was washed with distilled water until neutral, and then dried at 120°C for 4 hours to obtain a homogeneous solid mixture. The obtained solid mixture was calcined at 800°C for 4 hours to obtain the composite active component.

[0062] (2) Grind ammonium bicarbonate (4% by mass of the solid chlorine agent), kaolin (equivalent to 22 parts by mass of the binder component), and boehmite (equivalent to 17 parts by mass of alumina) to 300 mesh. Take the sieved mixed powder and mix it evenly with the composite active component obtained in step (1). Then add deionized water, the amount of which is 40% of the mass of the pore expander, carrier precursor, binder, and composite active component. Knead in a kneader at a speed of 35 r / min for 0.5 h until the material is in paste form. Take the above paste material and extrude it into shape using a twin-screw extruder with a 2 mm round die. Dry it in a 100℃ oven for 8 h to obtain the molded product.

[0063] (3) The molded product obtained in step (2) was immersed in a 0.20 mol / L lanthanum nitrate aqueous solution, dried at 120°C for 8 h, and then calcined at 500°C for 5 h to obtain the required high-temperature chlorine-fixing agent E. The composition of the chlorine-fixing agent is shown in Table 1, and the effect is shown in Table 2.

[0064] Example 6:

[0065] (1) Calcium hydroxide (equivalent to 18 parts calcium oxide), potassium carbonate (equivalent to 20 parts potassium oxide), and iron oxide (equivalent to 9 parts) were ground evenly in a vibratory grinder to a fineness of 300 mesh. The sieved material was mixed with a 4 mol / L ammonia solution and added to a reaction vessel for reaction. The amount of alkali solution added was adjusted to control the solid-liquid mass ratio in the reaction vessel to be 1:8. The mixture was heated uniformly at 80°C for 10 hours, and the reaction was carried out with stirring at 80 rpm. After the reaction was completed, the mixture was vacuum filtered, the filter cake was washed with distilled water until neutral, and then dried at 120°C for 4 hours to obtain a homogeneous solid mixture. The obtained solid mixture was calcined at 800°C for 4 hours to obtain the composite active component.

[0066] (2) Grind ammonium bicarbonate (4% by mass of the solid chlorine agent), kaolin (equivalent to 22 parts by mass of the binder component), and boehmite (equivalent to 17 parts by mass of alumina) to 300 mesh. Take the sieved mixed powder and mix it evenly with the composite active component obtained in step (1). Then add deionized water, the amount of which is 40% of the mass of the pore expander, carrier precursor, binder, and composite active component. Knead in a kneader at a speed of 35 r / min for 0.5 h until the material is in paste form. Take the above paste material and extrude it into shape using a twin-screw extruder with a 2 mm round die. Dry it in a 100℃ oven for 8 h to obtain the molded product.

[0067] (3) The molded product obtained in step (2) was immersed in a 0.20 mol / L lanthanum nitrate aqueous solution, dried at 120°C for 8 h, and then calcined at 500°C for 5 h to obtain the desired high-temperature chlorination agent F. The composition of the chlorination agent is shown in Table 1, and the effect is shown in Table 2.

[0068] Example 7:

[0069] (1) Weigh out 23 parts calcium carbonate (calcium oxide), 21 parts sodium carbonate (sodium oxide), 10 parts potassium carbonate (potassium oxide), 10 parts strontium carbonate (strontium oxide), 3 parts silicon dioxide, and 5 parts iron oxide. Grind them evenly in a vibratory grinder to a fineness of 200 mesh. Mix the sieved material with a 2 mol / L ammonia solution and add it to a reaction vessel for reaction. Adjust the amount of alkali solution added to control the solid-liquid mass ratio in the reaction vessel to be 1:5. Heat the mixture uniformly at 65°C for 6 hours; the reaction is carried out with stirring at 50 rpm. After the reaction is complete, vacuum filter the mixture. Wash the filter cake with distilled water until neutral, and then dry it at 120°C for 4 hours to obtain a homogeneous solid mixture. Calcine the obtained solid mixture at 800°C for 3 hours to obtain the composite active component.

[0070] (2) Grind ammonium bicarbonate (3% of the solid chlorine agent mass), kaolin (equivalent to 20 parts of the binder component), and boehmite (equivalent to 25 parts of alumina) to a fineness of 200 mesh or higher. Take the sieved mixed powder and mix it evenly with the composite active component obtained in step (1). Then add deionized water, the amount of which is 30% of the mass of the pore expander, carrier precursor, binder, and composite active component. Knead the mixture in a kneader at a speed of 20 r / min for 1 h until the material is in paste form. Extrude the paste into a shape using a 2 mm round die in a twin-screw extruder and dry it in a 100℃ oven for 6 h to obtain the molded product.

[0071] (3) The molded material obtained in step (2) is immersed in an aqueous solution containing 0.14 mol / L cerium nitrate and 0.14 mol / L lanthanum nitrate, dried at 120°C for 8 hours, and then calcined at 600°C for 6 hours to obtain the desired high-temperature chlorination agent G. The composition of the chlorination agent is shown in Table 1, and the effect is shown in Table 2.

[0072] Table 1

[0073]

[0074] Test case

[0075] The application effect of the solid chlorine agent was tested. The chlorine content of the coal sample used in this invention was 3052 μg / g. The solid chlorine agent prepared in the example was placed in a customized high-temperature combustion hydrolysis furnace at an agent-to-coal mass ratio of 1:25. The reaction temperature was adjusted to 700–1100℃ as needed, and the oxygen volume hourly space velocity was 420 h⁻¹. -1 The ratio of water vapor to oxygen, by volume, is 0.5:70. The performance parameters of the solid chlorine agent and the results of solid chlorine determination are shown in Table 2.

[0076] Table 2

[0077] Chlorine-fixing agent A B C D E F G Pore ​​volume, mL / g 0.76 0.69 0.58 0.56 0.69 0.64 0.68 <![CDATA[Specific surface area, m 2 / g]]> 202.8 190.2 180.5 167.8 176.7 172.8 196.1 Particle strength, N / cm 100.4 86.6 87.4 92.6 72.7 89.2 97.3 Chlorine fixation rate at 600℃, % 89.2 87.2 72.9 64.1 56.3 63.6 89.3 Chlorine fixation rate at 700℃, % 85.5 79.4 67.4 45.3 41.5 46.3 86.5 Chlorine fixation rate at 750℃, % 79.3 76.8 58.6 38.8 33.8 39.6 78.2 Chlorine fixation rate at 800℃, % 74.2 72.4 46.1 31.0 28.7 33.4 77.9 Chlorine fixation rate at 900℃, % 69.1 68.3 37.7 17.2 15.6 18.1 74.1 Chlorine fixation rate at 1000℃, % 67.7 66.9 29.5 9.4 7.8 10.4 68.6 Chlorine fixation rate at 1100℃, % 65.4 63.1 18.3 4.7 2.1 6.2 64.8

[0078] As can be seen from Table 2, changing the content of each component has a certain impact on the effect of the chlorine-fixing agent. The present invention has a better chlorine-fixing effect at temperatures of 600–1100℃, especially 750–1100℃.

[0079] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A chlorine-fixing agent, characterized in that, include: The active component comprises 25-70 parts by weight, 1-20 parts by weight of additives, 10-30 parts by weight of carrier, 15-25 parts by weight of binder component, and 1-5 parts by weight of rare earth oxides; the carrier is alumina; the additives include silicon dioxide and iron oxide; wherein the mass ratio of silicon dioxide to iron oxide is 0.6:1 to 5:1; and the mass ratio of the active component to the additives is 3:1 to 12:

1.

2. The chlorine-fixing agent according to claim 1, characterized in that, In the additive, the mass ratio of silicon dioxide to iron oxide is 0.6:1 to 3.5:

1.

3. The chlorine-fixing agent according to claim 1, characterized in that, The active component includes at least one of calcium oxide, sodium oxide, potassium oxide, and strontium oxide.

4. The chlorine-fixing agent according to claim 1, characterized in that, The rare earth oxides include at least one of cerium oxide and lanthanum oxide.

5. The chlorine-fixing agent according to claim 1, characterized in that, The chlorine-fixing agent is a high-temperature chlorine-fixing agent; the application temperature of the chlorine-fixing agent is 600~1100℃.

6. The chlorine-fixing agent according to claim 5, characterized in that, The chlorine-fixing agent is a high-temperature chlorine-fixing agent; the application temperature of the chlorine-fixing agent is 700~1100℃.

7. The chlorine-fixing agent according to claim 5, characterized in that, The chlorine-fixing agent is a high-temperature chlorine-fixing agent; the application temperature of the chlorine-fixing agent is 800~1100℃.

8. The chlorine-fixing agent according to claim 5, characterized in that, The chlorine-fixing agent is a high-temperature chlorine-fixing agent; the application temperature of the chlorine-fixing agent is 900~1100℃.

9. A method for preparing the solid chlorine agent according to any one of claims 1 to 8, comprising the following steps: (1) After grinding and mixing the active component source and the auxiliary agent evenly, react with an alkaline solution to separate the solid, wash, dry and calcine to obtain the composite active component; (2) Mix the pore-expanding agent, carrier precursor, binder and the composite active component obtained in step (1) evenly; add water, knead into shape, dry to obtain the molded product; (3) The molded material obtained in step (2) is immersed in a rare earth metal salt solution, dried and calcined to obtain a solid chlorine agent.

10. The preparation method according to claim 9, characterized in that, In step (1), the alkaline solution is ammonia water; adjust the amount of alkaline solution added to control the solid-liquid mass ratio in the reaction liquid in the reactor to be 1:5~1:

15.

11. The preparation method according to claim 10, characterized in that, The molar concentration of the alkaline solution in step (1) is 2~6 mol / L.

12. The preparation method according to claim 10, characterized in that, In step (1), adjust the amount of alkali solution added to control the solid-liquid mass ratio in the reaction liquid in the reactor to be 1:5~1:

9.

13. The preparation method according to claim 9, characterized in that, In step (1), the reaction temperature is 65~98℃ and the time is 6~20 h; the reaction is carried out under stirring at 50~100 rpm. And / or, the drying conditions are a temperature of 100~150 ℃ and a time of 4~12 h; And / or, the calcination conditions are a temperature of 800~900 ℃ and a time of 2~8 h.

14. The preparation method according to claim 9, characterized in that, The pore-expanding agent in step (2) includes ammonium bicarbonate; the carrier precursor includes boehmite; and the binder includes kaolin.

15. The preparation method according to claim 14, characterized in that, In step (2), the amount of the pore-expanding agent added is 1% to 5% of the mass of the solid chlorine agent.

16. The preparation method according to claim 9, characterized in that, The impregnation in step (3) is an equal volume impregnation; the drying conditions are: temperature 100~150℃, time 3~12 h; the calcination conditions are: temperature 450~700℃, time 2~10 h.

17. The application of a solid chlorine agent according to any one of claims 1 to 8 or a solid chlorine agent prepared by any one of claims 9 to 16 in coal chemical industry.

Images