CN115874001A - Method for Determining Composition of Blast Furnace Bosh Gas with Multimedia Injection - Google Patents

Abstract

The invention relates to a method for determining components of coal gas at a furnace belly of a multi-medium injection blast furnace, belonging to the field of blast furnace iron making. The specific method comprises the following steps: firstly, determining the types of the blowing media of the blast furnace tuyere, and inputting the components, the blowing amount and the coke components of each blowing media of the tuyere; secondly, calculating the coke amount consumed by the tuyere raceway; then, the conversion of each injected medium and coke into CO and N is calculated respectively ₂ 、H ₂ And the content of SiO; then, calculating the content of each component of the furnace belly coal gas; and finally, calculating the total gas quantity of the furnace bosh and the proportion of each component according to the content of each component of the furnace bosh gas. The invention overcomes the problem of deviation of the traditional furnace chamber coal gas quantity calculation method, can accurately calculate the furnace chamber coal gas quantity and the composition of the blast furnace, provides reliable data for the calculation of important parameters of the blast furnace, namely furnace chamber coal gas quantity index and theoretical combustion temperature, and provides better guidance for the operation of the blast furnace.

Description

Method for Determining Composition of Blast Furnace Bosh Gas with Multimedia Injection

technical field

The invention belongs to the field of blast furnace ironmaking, and relates to a method for determining the composition of the bosh gas of a multi-media injection blast furnace.

Background technique

计算的，其中V_B为风量，不包含富氧量，m³/min；V_O2为总富氧量，m³/min；W_B为鼓风湿度，g/m³；P_c为喷吹煤粉量kg/h；H煤粉含氢量，％。该公式仅考虑了煤粉固定碳和挥发分中氢元素的影响，未考虑挥发分中CO₂、碳氢化合物中C、CO、N₂、H₂O及煤粉物理水、煤粉灰分中SiO₂、Fe₂O₃还原产生CO、喷煤载气等的影响。高炉工序碳排放占高-转长流程工艺碳排放的70％以上。Blast furnace is one of the main equipments for producing molten iron at home and abroad. Bosh gas volume index and theoretical combustion temperature are two important parameters of blast furnace smelting. Among them, the bosh gas volume index is the superficial flow velocity of the gas produced in the tuyere swirl area under the standard state, and is an important index for evaluating the production efficiency of the blast furnace. The theoretical combustion temperature is an important reference index for judging the thermal state of the blast furnace hearth. The accuracy of bosh gas calculation directly determines the accuracy of the above two parameters. The inaccurate calculation of the theoretical combustion temperature and bosh gas volume index may cause the blast furnace operator to misjudge the furnace condition and affect the stability of the blast furnace. Under the condition of pulverized coal injection in the blast furnace, the bosh gas volume V _BG generally adopts

Calculated, where V _B is air volume, excluding oxygen enrichment, m ³ /min; V _O2 is total oxygen enrichment, m ³ /min; W _B is blast humidity, g/m ³ ; P _c is injection The amount of pulverized coal kg/h; the hydrogen content of H pulverized coal, %. This formula only considers the influence of carbon fixed in coal powder and hydrogen in volatile matter, and does not consider CO ₂ in volatile matter, C, CO, N ₂ , H ₂ O in hydrocarbons, physical water in coal powder, and coal dust in coal powder. The reduction of SiO ₂ and Fe ₂ O ₃ produces CO, coal injection carrier gas and so on. The carbon emission of the blast furnace process accounts for more than 70% of the carbon emission of the high-to-long process.

The composition of bosh gas, especially the content of CO and H ₂ in bosh gas, directly affects the reduction behavior of blast furnace charge. After the blast furnace adopts the new carbon reduction technology, the tuyere has changed from the original two injection media of hot air and coal injection to three injection media of hot air, coal powder, and CO-H2-CH4-CH ₄ rich reducing gas. The traditional coal injection blast furnace The formulas for calculating belly gas volume and composition are no longer applicable to low-carbon blast furnace multi-medium injection blast furnaces.

Contents of the invention

In view of this, the object of the present invention is to provide a method for determining the bosh gas composition of a multi-medium injection blast furnace, so as to overcome the problem of deviation in the traditional calculation method of bosh gas.

To achieve the above object, the present invention provides the following technical solutions:

A method for determining the composition of the bosh gas of a multi-medium injection blast furnace, comprising the following steps:

S1 determines the type of injection medium at the tuyere of the blast furnace, and inputs the composition, injection volume and coke composition of each injection medium at the tuyere;

S2 Calculate the amount of coke consumed in the tuyere gyration zone by the mass conservation of oxygen elements before and after the reaction in the tuyere gyration zone;

S3 According to the characteristics of the tuyere injection medium and coke consumed by the tuyere, the gas is composed of _four components: CO, N ₂ , H ₂ and SiO after the reaction in the tuyere swirl zone, according to Gaiss' law, according to the tuyere injection medium and coke composition and consumption Calculate the content of each injection medium and coke converted into CO, N ₂ , H ₂ and SiO;

S4 calculates the content of each component of bosh gas according to the content of CO, N ₂ , H ₂ and SiO produced by each injection medium and coke;

S5 calculates the total bosh gas volume and the ratio of each component from the content of each component of the bosh gas.

Optionally, the injection medium at the tuyere of the blast furnace is one or more combinations of air, coal powder, CO-H ₂ -CH ₄ -rich reducing gas, and oxygen; ₂ -CH ₄ reduced gas is one or more of coke oven gas, natural gas, coal bed methane, converter gas decarbonization gas, Ouye furnace decarbonization gas, blast furnace top decarbonization gas, etc.

Optionally, the components of the pulverized coal that can be converted into bosh gas mainly include pulverized coal fixed carbon, volatile matter in pulverized coal, SiO ₂ and Fe ₂ O ₃ in pulverized coal ash, and pulverized coal physical water; the coke can be The main components converted into bosh gas are coke fixed carbon, SiO ₂ and Fe ₂ O ₃ in coke ash.

Optionally, the fixed carbon in the pulverized coal combines with oxygen to form CO into the bosh gas at a ratio of 60% to 100%, and all volatiles are converted into CO, H ₂ and N ₂ into the bosh gas.

Optionally, the SiO ₂ in the pulverized coal and coke ash is reduced to CO and the ratio of SiO is 0%-50%.

Optionally, the reduction ratio of Fe ₂ O ₃ in the pulverized coal and coke ash to CO is 50%-100%.

Optionally, the oxygen in the air and the oxygen in the injection medium are all combined with CO in coke, coal powder, and hydrocarbons in the injection gas to enter the bosh gas.

Optionally, the composition input of the pulverized coal in the tuyere injection medium includes industrial analysis components, pulverized coal ash components, and pulverized coal volatile components.

Optionally, the air in the blast furnace tuyere injection medium mainly includes nitrogen and water.

Optionally, the composition input of the air in the blowing medium at the tuyere includes oxygen content, nitrogen content and humidity content.

The beneficial effects of the present invention are:

A method for determining the composition of blast furnace bosh gas by multi-media injection described in the present invention overcomes the problem of deviation in the traditional calculation method of bosh gas volume, and can accurately calculate the volume and composition of blast furnace bosh gas, which is an important parameter of blast furnace —The calculation of bosh gas volume index and theoretical combustion temperature provides reliable data and better guidance for blast furnace operation.

Other advantages, objects and features of the present invention will be set forth in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the investigation and research below, or can be obtained from It is taught in the practice of the present invention. The objects and other advantages of the invention may be realized and attained by the following specification.

Description of drawings

In order to make the purpose of the present invention, technical solutions and advantages clearer, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

Fig. 1 is the flow chart of the present invention.

Detailed ways

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the diagrams provided in the following embodiments are only schematically illustrating the basic concept of the present invention, and the following embodiments and the features in the embodiments can be combined with each other in the case of no conflict.

Wherein, the accompanying drawings are for illustrative purposes only, and represent only schematic diagrams, rather than physical drawings, and should not be construed as limiting the present invention; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, Enlargement or reduction does not represent the size of the actual product; for those skilled in the art, it is understandable that certain known structures and their descriptions in the drawings may be omitted.

In the drawings of the embodiments of the present invention, the same or similar symbols correspond to the same or similar components; , "front", "rear" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred devices or elements must It has a specific orientation, is constructed and operated in a specific orientation, so the terms describing the positional relationship in the drawings are for illustrative purposes only, and should not be construed as limiting the present invention. For those of ordinary skill in the art, the understanding of the specific meaning of the above terms.

See Figure 1, Example 1

This embodiment relates to a method and system for determining the composition of the bosh gas of a multi-media injection blast furnace. The method for calculating the composition of the bosh gas of a low-carbon blast furnace multi-media injection is performed according to the following steps:

Step 1. In this embodiment, the tuyere injection medium is air, coal powder (including coal injection carrier gas), coke oven gas, and oxygen, and the components are shown in Table 1-Table 3 respectively. The carrier gas for coal injection is N ₂ , and the carrier gas ratio is 30kg/kgN ₂ . The injection volumes of air, pulverized coal, coke oven gas and oxygen are 855m ³ /tHM, 131.3kg/tHM, ^{50m 3} /tHM and 64m ³ /tHM respectively.

Table 1 Air composition, volume fraction

project O₂ N₂ H₂O unit % % % value twenty one 78 1

Table 2 Composition of pulverized coal injection at blast furnace tuyere, mass percentage%.

Table 3 Composition of blast furnace tuyere injection gas, volume percentage %.

CH₄ H₂ CO CO₂ N₂ H₂O 24.80 63.51 7.85 2.36 1.48 0.0

Step 2, the components of the coke consumed by the blast furnace tuyere are shown in Table 4. According to the mass conservation of oxygen elements before and after the reaction in the tuyere gyration, the coke consumption in the tuyere gyration is calculated to be 223.65kg/tHM.

Table 4 Composition of coke consumed by blast furnace tuyere, mass percentage%.

In step 3, coal powder fixes carbon and combines with oxygen to generate CO into bosh gas at a ratio of 80%, and the reduction rates of Fe ₂ O ₃ and SiO ₂ in ash are 6% and 100%, respectively. From coal powder composition, injection amount, C+O ₂ =2CO, C+H ₂ O=CO+H ₂ , CnHm+n/2O ₂ =nCO+m/2H ₂ , CO ₂ +C=2CO, SiO ₂ +C＝SiO+CO, Fe ₂ O ₃ +3C＝3CO+2Fe and the pulverized coal volatile CO, H ₂ , N ₂ directly enter the bosh gas, and it can be calculated that the bosh gas produced by the pulverized coal is 193.688m ³ /tHM, where H ₂ , CO, N ₂ and SiO are 11.822, 180.080, 1.691, ^{0.095m 3} /tHM, respectively.

Step 4: Calculate the bosh gas volume produced by the pulverized coal carrier gas from the amount of coal injection and the carrier gas ratio to be 3.502m ³ /tHM.

Step 5, from coke oven gas components, C+H ₂ O=CO+H ₂ , CnHm+n/2O ₂ =nCO+m/2H ₂ , CO ₂ +C=2CO and CO, H ₂ , N ₂ directly enters the bosh gas, and the bosh gas volume generated by the injection gas is calculated to be 75.980m ³ /tHM, of which H ₂ , CO, and N ₂ are 56.555, 18.685, and 0.740m ³ /tHM, respectively.

Step 6, from the amount of air injection, composition, C+H ₂ O=CO+H ₂ and N ₂ in the air directly into the bosh gas, the calculated bosh gas volume generated by air injection is 686.143m ³ / tHM, where H ₂ , CO, and N ₂ are 8.837, 8.837, and 668.468m ³ /tHM, respectively.

In step 7, the reduction rates of Fe ₂ O ₃ and SiO ₂ in the coke ash consumed by the tuyeres are 6% and 100%, respectively. According to the tuyere coke consumption, composition, C+O ₂ =2CO, SiO ₂ +C=SiO+CO, Fe ₂ O ₃ +3C=3CO+2Fe, the bosh gas volume produced by the tuyere consumption coke is calculated to be 332.683m ³ /tHM, where CO and SiO are 332.392 and 0.291m ³ /tHM, respectively.

Step 8, the amount of gas calculated from steps 3 to 7, the total amount of bosh gas can be calculated as 1288.494m ³ /tHM, of which H ₂ , CO, N ₂ and SiO are 77.214, 539.995, 674.401, and 0.386m ³ respectively /tHM, the volume fractions are 5.99%, 41.91%, 52.34%, 0.03%, respectively.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements, without departing from the spirit and scope of the technical solution, should be included in the scope of the claims of the present invention.

Claims (10)

1. A method for determining the gas composition of a multi-medium injection blast furnace belly is characterized by comprising the following steps:

s1, determining the types of blowing media of a blast furnace tuyere, and inputting the components, the blowing amount and the coke components of each blowing media of the tuyere;

s2, calculating the coke amount consumed by the tuyere raceway by mass conservation of oxygen before and after reaction in the tuyere raceway;

s3, according to the fact that the tuyere blows the medium and the tuyere consumes the coke, the coal gas is reacted by CO and N through a tuyere convolution area ₂ 、H ₂ And SiO ₄ The characteristic of the composition of the components is calculated according to the components and the consumption of the blowing medium and the coke at the tuyere by the Gauss law ₂ 、H ₂ And the content of SiO;

s4, according to CO and N generated by each injection medium and coke ₂ 、H ₂ And the content of SiO, calculating the content of each component of the furnace bosh gas;

s5, calculating the total gas quantity of the furnace bosh and the proportion of each component according to the content of each component of the furnace bosh gas.

2. The method for determining the coal gas composition of the multi-medium blowing blast furnace belly according to claim 1, characterized in that the blast furnace tuyere blowing medium is air, pulverized coal, rich in CO-H ₂ -CH ₄ Reducing one or more of coal gas and oxygen; CO-H-enriched air is sprayed in the tuyere injection medium ₂ -CH ₄ The reducing gas is one or more of coke oven gas, natural gas, coal bed gas, converter gas decarburization gas, european and metallurgical furnace decarburization gas, blast furnace top decarburization gas and the like.

3. The method for determining the composition of coal gas in a multi-media injection blast furnace according to claim 2, wherein the composition of coal dust which can be converted into coal gas in the furnace is mainly coal dust fixed carbon, coal dust volatile matter, siO in coal dust ash ₂ And Fe ₂ O ₃ Physical water of the pulverized coal; the coke can be converted into furnace gas mainly containing coke fixed carbon and SiO in coke ash ₂ And Fe ₂ O ₃ 。

4. The method for determining the coal gas composition of the multi-medium injection blast furnace belly according to claim 2, characterized in that the ratio of CO generated by combining fixed carbon in the pulverized coal and oxygen to enter the coal gas of the furnace belly is 60-100%, and all volatile components are converted into CO and H ₂ And N ₂ And enters the furnace chamber coal gas.

5. The method for determining the gas composition of the multi-media injection blast furnace belly according to claim 2, characterized in that SiO in the pulverized coal and coke ash ₂ The proportion of reducing to CO and SiO is 0-50%.

6. The method for determining the gas composition of the multi-media injection blast furnace belly according to claim 2, characterized in that the Fe in the coal dust and the coke ash ₂ O ₃ The proportion of reduced CO is 50% ~ to100％。

7. The method for determining the composition of the coal gas of the multi-medium injection blast furnace belly according to claim 2, characterized in that the oxygen in the air and the oxygen in the injection medium are combined with the carbon in the carbon-containing compound in the coke, the coal powder and the injection gas to form CO, and then the CO enters the coal gas of the belly.

8. The method for determining the coal gas composition of the multi-medium injection blast furnace belly according to claim 2, characterized in that the composition input of the pulverized coal in the tuyere injection medium comprises composition components of industrial analysis components, ash components of the pulverized coal and volatile components of the pulverized coal.

9. The method for determining the composition of a gas in a multi-media injection blast furnace muffle of claim 1, wherein the composition of the gas in the blast furnace tuyere injection media is primarily convertible to the gas in the muffle; nitrogen and moisture.

10. The method of claim 1, wherein the composition inputs of air in the tuyere injection medium comprise oxygen content, nitrogen content and humidity content.

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