阅读说明：本技术 复合铁酸钙协同脱除高炉煤气中的硫化物和co2的方法 (Synergistic removal of sulfide and CO in blast furnace gas by composite calcium ferrite2Method (2) ) 是由 魏振浩 徐庆余 徐华祥 于 2019-09-23 设计创作，主要内容包括：本发明涉及高炉煤气脱除有机硫和CO_2领域,具体涉及以功能性复合铁酸钙协同脱除高炉煤气中的硫化物和CO_2的方法；其特征在于：这种以功能性复合铁酸钙协同脱除高炉煤气中的硫化物和CO_2的方法：除尘后的高炉煤气进入脱硫脱碳装置,经复合铁酸钙后,CO_2被功能性复合铁酸钙吸附碳酸化；羰基硫在功能性复合铁酸钙碱性中心发生水解,产生H_2S,H_2S与功能性复合铁酸钙的金属氧化物活性中心发生反应,转化为金属硫化物；通过CO_2的吸附碳酸化和羰基硫的化学反应,实现协同脱除高炉煤气中硫化物和CO_2,通过在氧气气氛下实现氧化再生后功能性复合铁酸钙循环使用。(The invention relates to the removal of organic sulfur and CO from blast furnace gas 2 The field, in particular to the synergistic removal of sulfide and CO in blast furnace gas by functional composite calcium ferrite 2 The method of (1); the method is characterized in that: the functional composite calcium ferrite is used for synergistically removing sulfide and CO in blast furnace gas 2 The method of (1): the blast furnace gas after dust removal enters a desulfurization and decarbonization device, and is subjected to CO after being compounded with calcium ferrite 2 is absorbed and carbonated by functional composite calcium ferrite; carbonyl sulfide is hydrolyzed in the basic center of functional composite calcium ferrite to generate H 2 S，H 2 S reacts with the active center of the metal oxide of the functional composite calcium ferrite to be converted into metal sulfide; by CO 2 The chemical reaction of the adsorption carbonation and the carbonyl sulfide realizes the synergistic removal of sulfide and CO in the blast furnace gas 2 The functional composite calcium ferrite circulation after oxidation regeneration is realized under the oxygen atmosphereThe preparation is used.)

1. A preparation method of composite calcium ferrite is characterized by comprising the following steps:

(1) Mixing a ferric nitrate solution and a calcium nitrate solution to obtain a mixed solution A, wherein the ferric nitrate and the calcium nitrate are added according to a molar ratio of Ca to Fe (0.5-1.5): 1, preferably (0.8-1): 1;

(2) Adding an ammonium oxalate solution into the solution A, uniformly stirring to obtain a mixed solution B, heating the mixed solution B to 50-80 ℃, and adjusting the pH value with an alkaline reagent to generate an emulsion C; wherein the adding amount of the ammonium oxalate is 0.5-3 times of the molar amount of (Ca + Fe) in the mixed solution A, and preferably 1-3 times; the PH value is 6-10;

(3) Placing the emulsion C in a microwave reactor at 100-300 ℃ for 0.5-2 h, washing with water, washing with alcohol, drying and grinding to obtain solid powder D;

(4) And (3) placing the solid powder D in a muffle furnace, heating to 500-850 ℃ at a heating rate of 3-5 ℃/min, calcining at a constant temperature for 2-6 h, and grinding the calcined solid powder D to finally obtain the composite calcium ferrite.

2. The method of claim 1, wherein: the concentrations of the ferric nitrate and the calcium nitrate in the step (1) are 0.25-1.0 mol/L; the concentration of the ammonium oxalate solution in the step (2) is 0.25-1.0 mol/L, preferably 0.35-0.85 mol/L.

3. The method of claim 1, wherein: and (3) the alkaline reagent in the step (2) is one or more of urea, ammonia water, NaOH and monoethanolamine, and the PH is 7.5-10.

4. The method of claim 1, wherein: and (4) the temperature is 550-750 ℃, and the calcining time is 3-6 h.

5. The complex calcium ferrite obtained by the production method according to any one of claims 1 to 4.

6. A composite calcium ferrite obtained by the preparation method of any one of claims 1 to 4 is used for synergistically removing sulfides and CO in blast furnace gas₂The method of (1).

7. The method of claim 6, wherein: the composite calcium ferrite is crushed into 5-10 mesh catalyst particles after being pressed and formed.

8. The method of claim 6, wherein: filling the composite calcium ferrite in a desulfurization and decarburization device at the middle part of a desulfurization and decarburization reactor, feeding the blast furnace gas subjected to dust removal into the desulfurization and decarburization reactor, and performing synergistic removal of sulfide and CO in the blast furnace gas after the composite calcium ferrite₂。

9. The method of claim 6, wherein: the compound calcium ferrite synergistically removes sulfide and CO in blast furnace gas₂the reaction temperature of (a) is 200 to 500 ℃, preferably 250 to 500 ℃; the airspeed is 500-5000 h^-1Preferably 2500-5000 h^-1(ii) a The pressure is 6 to 20Kpa, preferably 8 to 16 Kpa.

10. A regeneration method of composite calcium ferrite is characterized in that: and regenerating the inactivated composite calcium ferrite in an oxygen atmosphere at 850 ℃ and preferably at 800 ℃ and 500 ℃ for 0.5-6h, preferably 0.5-1.5 h to obtain the regenerated composite calcium ferrite.

Technical Field

The invention relates to the removal of organic sulfur and CO from blast furnace gas₂The field, in particular to the synergistic removal of sulfide and CO in blast furnace gas by functional composite calcium ferrite₂the method of (1).

Background

The iron and steel industry is an important basic industry in China, and the refined iron and steel has the characteristics of large process energy consumption, high emission, serious environmental pollution and the like. Blast furnace gas as a steel production streamImportant byproducts of the in-process blast furnace ironmaking process are preheated air, coke and CO and H generated in the combustion process of iron ore₂、CO₂、N₂And CH₄And the like, and generally accounts for more than 50% of the energy supply amount in blast furnace ironmaking. The main components of blast furnace gas are CO and N₂、CO₂、H₂、CH₄Sulfide, wherein CO accounts for about 25 percent, CO₂、N₂about 16% and 58% respectively, and the total sulfur content is about 200mg/m³。

The sulfur in the blast furnace gas mainly comprises carbonyl sulfide (COS) and hydrogen sulfide (H)₂S), carbon disulfide (CS)₂) Mainly, the three sulfur components account for about 95 percent of the total sulfur, wherein carbonyl sulfur accounts for about 68 percent of the total sulfur, hydrogen sulfide accounts for about 28 percent of the total sulfur, and carbon disulfide accounts for about 19 percent of the total sulfur.

With the improvement of the environmental protection standard and the implementation of the greenhouse gas emission reduction policy, the efficient, reasonable and clean utilization of the blast furnace gas is the key for realizing energy conservation, consumption reduction, low carbon and emission reduction of steel enterprises. The method has low cost, large-scale removal of sulfides in blast furnace gas and high efficiency CO capture₂The method is two major technical problems for realizing the resource utilization of the blast furnace gas in the steel industry.

Aiming at the blast furnace gas desulfurization technology, no mature and accepted technical route exists at present. The main technical problems are as follows: the existence form of sulfur in blast furnace gas is complex, and the existing inorganic sulfur H₂S, COS and CS₂And the like, and high-temperature treatment easily causes a series of problems of reactor corrosion, catalyst poisoning and the like, thereby seriously restricting the resource utilization of the blast furnace gas.

In general, the process for removing organic sulfur is more SO than SO₂、H₂The removal process of S is complex and has higher cost, and the blast furnace gas desulfurization also relates to the safety problem, so the blast furnace gas desulfurization technology is more complex than the common flue gas desulfurization technology. The removal method of COS mainly comprises catalytic hydrolysis, namely carbonyl sulfide is converted into H under the condition of catalyst₂And S. Common catalytic systems include transition metal oxides such as Fe₂O₃、MoO₃、ZrO₂、ZnO、TiO₂、SnO₂Etc., alkaline earth metal carbonate-modified metal oxides and rare earth metal oxides such as CeO₂、La₂O₃And the like. Generation of H₂S is removed through the sulfurization reaction of metal oxide and can be used for H₂the metal oxides removed by S include CaO and Fe₂O₃And ZnO, etc.

Chinese patent application CN108315070A discloses a method for removing carbonyl sulfide in liquefied petroleum gas by metal-doped KP type molecular sieve, which provides an alkaline center for carbonyl sulfide hydrolysis by a method for loading metal on KP type molecular sieve. The method is carried out by physical adsorption of carbonyl sulfide and H₂And the chemical adsorption synergistic effect of the S realizes the high-efficiency removal of carbonyl sulfide in the liquefied petroleum gas. The method has high removal efficiency, but the method has small amount of purified gas and short service life of the metal-doped KP molecular sieve, needs continuous hydrothermal regeneration, and has long and complicated regeneration process.

The development of green and low carbon is a common consensus and trend. Worldwide, projects around Low carbon steel manufacturing are started in succession, including the European Union Ultra-Low CO2 Steelmarking (ULCOS), American Iron and Steel institute with technology roadmap Programme (AISI) in the United states, and CO2 MultimateReduction in Steelmarking Process by innovative technology for cool Earth 2050 (COARSE) in Japan. The research on the carbon dioxide capture of blast furnace gas is the focus of the research on the carbon dioxide capture in the industrial sector.

Existing blast furnace gas CO₂The trapping technology is mainly divided into three categories: 1) decarburization in front of the furnace, and iron making by adopting non-carbon (such as hydrogen) or zero-carbon (such as biomass) fuels; 2) carbon dioxide in the furnace is enriched, and the recycling of the top gas, pure oxygen and vacuum pressure swing absorption are adopted to realize the CO in the blast furnace tail gas₂Enriching; 3) gas CO after furnace₂And (4) separating, namely separating the carbon dioxide in the blast furnace gas by adopting solution absorption or a solid absorbent. The technology of decarburization in the front of the furnace and carbon dioxide enrichment in the furnace has the problems of high cost, large-scale transformation of the existing iron-making process and the like, and is difficult to popularize in a short period. After-furnace CO₂separation technique, flexibilityStrong, more simple to popularize, can be designed to be novel and has CO₂the blast furnace for trapping energy supply can be reformed based on the original blast furnace, and is the most promising blast furnace gas CO₂Separation techniques. Patent CN 108970332a discloses a "decarburization method for converter and/or blast furnace gas", which completes decarburization of converter and/or blast furnace gas by two steps of pressure swing adsorption rough decarburization and MDEA solution fine decarburization. The method can not only convert CO₂the content of the phosphorus is removed to PPM level, and meanwhile, the phosphorus hydride in the converter and blast furnace gas can be removed. However, the method has the defects of complicated steps, high investment, high energy consumption, high solvent consumption and the like, and has an unclear industrial prospect.

In conclusion, the near zero emission of blast furnace ironmaking is not separated from each other and the CO is cooperated with the desulfurization₂There is no solution to capture the support of two important technologies. Aiming at the problems that calcium, iron, copper and other metal oxides are frequently used in the desulfurization and decarburization processes, and the calcium and iron oxides are common raw materials for steel production, the method can not only solve the problem of removing sulfur-containing gas in blast furnace gas, but also can efficiently capture CO₂The multifunctional synergistic catalytic system can form an integrated technology of low-cost desulfurization and decarbonization of blast furnace gas.

Disclosure of Invention

The invention aims to provide the method for removing sulfide and CO in blast furnace gas by using functional composite calcium ferrite₂The method can remove the sulfide in the blast furnace gas in a large scale with low cost and can efficiently capture CO₂。

The technical scheme adopted by the invention for solving the technical problems is as follows: synergistic removal of sulfide and CO in blast furnace gas by functional composite calcium ferrite₂The method of (2), characterized by: the functional composite calcium ferrite is used for synergistically removing sulfide and CO in blast furnace gas₂The method of (1): the blast furnace gas after dust removal enters a desulfurization and decarbonization device, and is subjected to CO after being compounded with calcium ferrite₂Is absorbed and carbonated by functional compound calcium ferrite; carbonyl sulfide is hydrolyzed in the basic center of functional composite calcium ferrite to generate H₂S，H₂S and functionalityThe active center of the metal oxide of the composite calcium ferrite reacts and is converted into metal sulfide; by CO₂The chemical reaction of the absorption carbonation and the carbonyl sulfide realizes the synergistic removal of sulfide and CO in the blast furnace gas₂The functional composite calcium ferrite can be recycled after oxidation and regeneration under the oxygen atmosphere.

Specifically, the invention relates to a preparation method of composite calcium ferrite, which is characterized by comprising the following steps:

(1) Mixing a ferric nitrate solution and a calcium nitrate solution to obtain a mixed solution A, wherein the ferric nitrate and the calcium nitrate are added according to a molar ratio of Ca to Fe (0.5-1.5): 1, preferably (0.8-1): 1;

(2) Adding an ammonium oxalate solution into the solution A, uniformly stirring to obtain a mixed solution B, heating the mixed solution B to 50-80 ℃, and adjusting the pH value with an alkaline reagent to generate an emulsion C; wherein the adding amount of the ammonium oxalate is 0.5-3 times of the molar amount of (Ca + Fe) in the mixed solution A, and preferably 1-3 times; the PH value is 6-10;

(3) Placing the emulsion C in a microwave reactor at 100-300 ℃ for 0.5-2 h, washing with water, washing with alcohol, drying and grinding to obtain solid powder D;

(4) And (3) placing the solid powder D in a muffle furnace, heating to 500-850 ℃ at a heating rate of 3-5 ℃/min, calcining at a constant temperature for 2-6 h, and grinding the calcined solid powder D to finally obtain the composite calcium ferrite.

Preferably, the concentration of the ferric nitrate and calcium nitrate solution in the step (1) is 0.25-1.0 mol/L.

Preferably, the concentration of the ammonium oxalate solution in the step (2) is 0.25-1.0 mol/L, and more preferably 0.35-0.85 mol/L.

More preferably, the ammonium oxalate solution is added dropwise to the mixed solution a.

Preferably, the alkaline reagent in the step (2) is one or more of urea, ammonia water, NaOH and monoethanolamine, and the pH is 7.5-10.

Preferably, the temperature in the step (4) is 550-750 ℃, and the calcination time is 3-6 h.

The invention also relates to the composite calcium ferrite obtained by the preparation method.

The invention also relates to the synergistic removal of sulfide and CO in blast furnace gas by the composite calcium ferrite obtained by the preparation method₂The method of (1).

Preferably, the composite calcium ferrite is crushed into 5-10 meshes of catalyst particles after being pressed and formed.

Preferably, the invention relates to the synergistic removal of sulfide and CO in blast furnace gas by the composite calcium ferrite obtained by the preparation method of any one of the above₂The method of (2), characterized by: filling composite calcium ferrite in a desulfurization and decarbonization device at the middle part of a desulfurization and decarbonization reactor, feeding the blast furnace gas subjected to dust removal into the desulfurization and decarbonization device, and performing composite calcium ferrite to realize synergistic removal of sulfide and CO in the blast furnace gas₂。

More preferably, the composite calcium ferrite synergistically removes sulfide and CO in blast furnace gas₂The reaction temperature of (a) is 200 to 500 ℃, preferably 250 to 500 ℃; the airspeed is 500-5000 h^-1Preferably 2500-5000 h^-1(ii) a The pressure is 6 to 20Kpa, preferably 8 to 16 Kpa.

The invention also relates to a regeneration method of the composite calcium ferrite, which is characterized by comprising the following steps: and regenerating the inactivated composite calcium ferrite in an oxygen atmosphere at 850 ℃ and preferably at 800 ℃ and 500 ℃ for 0.5-6h, preferably 0.5-1.5 h to obtain the regenerated composite calcium ferrite.

The invention has the beneficial effects that:

(1) The invention adopts a multifunctional composite calcium ferrite material to circulate the carbon carrier and the sulfur carrier and creatively realizes the synergistic desulfurization and decarburization of blast furnace gas, the removal rate of carbonyl sulfide in the blast furnace gas treated by the composite calcium ferrite is 60-90 percent, and H is₂The removal rate of S is 80-98%, and CO is removed₂The removal rate is 30-70%;

(2) The preparation method of the multifunctional composite calcium ferrite is simple, and the materials used for synthesis are cheap and easy to obtain, so that the multifunctional composite calcium ferrite has a wide industrial application prospect;

(3) the multifunctional composite calcium ferrite has simple regeneration process, can realize the recycling by oxidizing regeneration in the oxygen atmosphere, and reduces the investment cost.

Detailed Description

The present invention will be further described with reference to the following examples. The described embodiments and their results are only intended to illustrate the invention and should not be taken as limiting the invention described in detail in the claims.