A method for calculating the SO2 content of exhaust gas from a gas-fired boiler mainly blended with blast furnace gas

Abstract

The invention discloses a method for calculating SO2 of exhaust gas from a gas-fired boiler mainly mixed with blast furnace gas. 2 The method for determining sulfur content in ton iron smelting and gas boiler combustion technology includes the following steps: sample collection, standard sample preparation, detection of sulfur content adsorbed on the surface of standard coke sample, conversion of sulfur form, calculation of sulfur content per ton iron SO 2 Emission, calculation of gas generation per ton of iron, calculation of combustion per m 3 Required air volume for complete combustion of gas, calculation of 1m 3 Flue gas generated by coal gas and calculation of SO in flue gas of gas boiler when blast furnace gas: converter gas = 9:1 2 The method of the present invention can predict the sulfur content in the exhaust gas of gas boilers in advance by combining the sulfur content adsorbed on the coke surface with the sulfur balance calculation model. 2 content, so that the coke ratio structure can be optimized and adjusted in advance to ensure that SO 2 The content is kept under control at all times.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace ironmaking and smelting and gas boiler combustion, and in particular to a method for calculating the SO2 content of waste gas from a gas boiler that mainly burns blast furnace gas. Background Art

[0002] Domestic coking plants mainly produce coke in horizontal coking furnaces, and all of them adopt quenching outside the furnace. There are two types of quenching outside the furnace: dry quenching and wet quenching. Among them, wet quenching has a simple process, low investment and low cost. Most domestic coking plants adopt wet quenching. In the wet quenching process, the high-temperature coke produced by the coke oven is transported to the quenching tower by a quenching truck, and water is directly sprayed on the high-temperature coke to cool it down.

[0003] With the continuous introduction of new environmental protection policies in the steel coking industry, the emission reduction standards for coking enterprises are becoming increasingly stringent. Coking plants mainly recycle coking wastewater (including desulfurization waste liquid) and treated circulating water in the quenching process to reduce water consumption and wastewater treatment costs. Coking wastewater (including desulfurization waste liquid) and treated circulating water contain a large amount of sulfur-containing substances and alkali metals and alkaline earth metals such as potassium, sodium, calcium, and magnesium. After participating in the coke quenching operation, the above-mentioned compounds are adsorbed on the surface of the coke in large quantities, and the sulfur adsorbed on the surface of the coke basically exists in the form of organic sulfur.

[0004] The sulfur-containing substances inside the coke include inorganic sulfur and organic sulfur, which eventually enter the blast furnace slag, and only a small proportion enters the blast furnace raw gas. The main reasons are: (1) The inorganic sulfur in the coke exists in the form of sulfides and sulfates, among which CaS directly enters the slag at the bottom of the blast furnace. When sulfates come into contact with SO2, Al2O3, Fe2O3, etc., they will also decompose or generate silicates and directly enter the blast furnace slag; (2) About 50% to 75% of the organic sulfur in the coke evaporates into the coal gas in the form of S, SO2, H2S, etc. before reaching the tuyere, and the rest burns before the tuyere to generate SO2. Under high-temperature reducing atmosphere conditions, SO2 is quickly reduced by C and generates sulfur vapor, CS, CS2, HS, H2S and other sulfides under the action of other substances, which rise with the coal gas. During the rising process, except for a small part being carried away by the coal gas, the rest is absorbed by the CaO, iron oxide or reduced Fe in the charge and transferred into the charge, and falls with the charge; the CaS generated by the reaction enters the slag at the lower part of the blast furnace, and part of the FeS is distributed in the slag, and the remaining sulfur or sulfide rises with the coal gas. Most of the sulfur is absorbed by the charge during the rising process and falls. In this way, the sulfur in the coke circulates in the furnace over and over again.

[0005] Therefore, the sulfur element in blast furnace gas mainly comes from sulfur-containing substances attached to or adsorbed on the surface of coke, and the sulfur element mainly comes from coking wastewater including desulfurization waste liquid, ammonia vapor wastewater and circulating water of the whole plant entering the coke quenching pool to participate in the coke quenching operation, resulting in the adsorption of a large amount of sulfur-containing substances on the surface of coke. When the gas-fired boiler of a steel enterprise mainly burns blast furnace gas, as the blast furnace gas burns, various forms of sulfur elements in the gas undergo oxidation reaction with oxygen, and finally exist in the gas-fired boiler exhaust gas mainly in the form of SO2. At present, there is still a lack of a method for calculating the SO2 content in the exhaust gas of a gas-fired boiler mainly burning blast furnace gas by detecting the content of sulfur-containing substances adsorbed on the surface of coke. Therefore, the present invention proposes a method for calculating the SO2 content in the exhaust gas of a gas-fired boiler mainly burning blast furnace gas, so as to solve the shortcomings in the prior art. Summary of the invention

[0006] In view of the above problems, the purpose of the present invention is to provide a method for calculating the SO2 content in the exhaust gas of a gas-fired boiler that mainly burns blast furnace gas. By combining the sulfur element adsorbed on the coke surface with a sulfur element balance calculation model, the SO2 content in the exhaust gas of the gas-fired boiler can be predicted in advance, thereby optimizing and adjusting the coke ratio structure in advance to ensure that the SO2 content in the exhaust gas of the gas-fired boiler is always kept under control.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for calculating the SO2 content of exhaust gas from a gas-fired boiler mainly mixed with blast furnace gas comprises the following steps:

[0009] Step 1: Sample collection: Sample the incoming coke according to GB / T 1997-2008, the standard for the collection and preparation of coke samples;

[0010] Step 2: Preparation of standard samples: subjecting the coke samples collected in step 1 to two-stage screening, and using the coke samples obtained after screening as standard coke samples;

[0011] Step 3: Detecting the sulfur content adsorbed on the surface of the standard coke sample, soaking the standard coke sample, filtering it, collecting the soaking liquid, and measuring the sulfur content in the soaking liquid;

[0012] Step 4: Convert the sulfur element form, and convert the sulfur element measured in step 3 into SO2 using formula (1);

[0013] M SO2 =(S)÷S(atomic weight)×(molecular weight) (1)

[0014] Step 5: Calculate the SO2 emission per ton of iron. Use formula (2) to calculate the SO2 emission per ton of iron.

[0015] Q SO2 =M SO2 × Focal ratio (2)

[0016] In formula (2), Q SO2 It is the SO2 emission per ton of iron, unit: mg / t·iron;

[0017] Step 6: Calculate the amount of coal gas generated per ton of iron. Use formula (3) to calculate the amount of coal gas generated per ton of iron.

[0018] V g =C g ×22.4÷[12×((CO2)+(CO)+(CH4))] (3)

[0019] Step 7: Calculate the burning time for 1m 3 The amount of air required for gas combustion is calculated using formula (4). 3 The amount of air required for gas;

[0020] L = α × L o (4)

[0021] Step 8: Calculate the complete combustion of 1m 3 The flue gas produced by coal gas is calculated using formula (5) for complete combustion of 1m 3 The amount of smoke produced by coal gas;

[0022] V y =V CO2 +V H2O +V N2 +V O2 +V SO2 (5)

[0023] Step 9: Calculate the amount of SO2 in the flue gas of the gas-fired boiler when the ratio of blast furnace gas to converter gas is 9:1. Use formula (6) to calculate the amount of SO2 in the flue gas of the gas-fired boiler when the ratio of blast furnace gas to converter gas is 9:1.

[0024] C SO2 =Q SO2 ÷V y ×V g× 90% (6).

[0025] A further improvement is that when the coke sample is subjected to two-stage screening in step 2, sieves with 25mm×25mm and 40mm×40mm meshes are used to perform two-stage screening on the coke sample, and the coke sample with a particle size of 25mm-40mm obtained after screening is used as the standard coke sample.

[0026] A further improvement is that the specific operation of detecting the sulfur content adsorbed on the surface of the standard coke sample in step three is: soaking the standard coke sample in deionized water, filtering out the standard coke sample after soaking for four hours, and then taking the soaking liquid for testing to detect the sulfur content.

[0027] A further improvement is that: in the formula (1) of step 4, M SO2 is the amount of sulfur adsorbed on the surface of the standard coke sample converted into boiler flue gas SO2, in mg / kg; (S) is the total sulfur content in the standard coke sample immersion solution, in mg / L; S (atomic weight) is the atomic weight of sulfur; SO2 (molecular weight) is the molecular weight of SO2.

[0028] A further improvement is that: in the formula (3) of step 6, V g is the amount of gas per ton of iron, in m 3 / t; (CO2), (CO), (CH4) are the proportions of the corresponding components in the furnace top gas; C g It is the amount of gasified carbon per ton of pig iron, that is, the amount of carbon present in the coal gas, in kg.

[0029] A further improvement is that: the gasified carbon amount C g The calculation formula is shown in formula (7):

[0030] C g =K×(C) 焦 +M×(C) 煤 -C 尘 -C 渗 (7)

[0031] In formula (7), K and M are the coke ratio and coal ratio of blast furnace smelting, respectively, and the unit is kg / t; (C) 焦 (C) 煤 are the carbon content ratios of coke and coal powder respectively; C 尘 , C 渗 They are the amount of carbon carried away by furnace dust and the amount of carbon carburized in pig iron, respectively, in kg / t.

[0032] A further improvement is that: in the formula (4) of step 7, L is the total combustion volume of 1m 3 Actual air volume required for gas, m 3 ; L o For complete combustion 1m 3 Theoretical air volume required for gas, m 3 ; α is the excess air coefficient. Under complete combustion conditions, α takes the value of 1.05.

[0033] A further improvement is that: in the formula (4) of step 7, L o The calculation formula is shown in formula (8):

[0034] L o =(0.5(CO)+0.5(H2)+2(CH4)) / 21 (8).

[0035] A further improvement is that: in the formula (5) of step eight, V y For complete combustion 1m 3 The amount of flue gas produced by coal gas, in m 3 ; V CO2 For complete combustion 1m 3 The amount of CO2 produced by coal gas, in m 3 ; V H2O For complete combustion 1m 3 The amount of water vapor produced by coal gas, in m 3 ; V N2 For complete combustion 1m 3 The amount of N2 produced by coal gas, in m 3 ; V O2 For complete combustion 1m 3 The amount of O2 produced by coal gas, in m 3 ;

[0036] Among them, V CO2、 V H2O、 V N2和 V O2 The calculation formulas are shown in formulas (9), (10), (11), and (12) respectively:

[0037] V CO2 =0.01×((CO2)+(CO)+(CH4)) (9)

[0038] V H2O =0.01×((H2)+2(CH4)+(H2O)) (10)

[0039] V N2 =0.01×(N2)+0.79×L (11)

[0040] V O2 =0.21×(α-1)×L o。 (12)

[0041] A further improvement is that: in the formula (6) of step nine, C SO2 is the amount of SO2 in boiler flue gas, in mg / m 3 ; 90% is the proportion of blast furnace gas blended into gas boilers.

[0042] The beneficial effects of the present invention are as follows: the method of the present invention can realize the prediction and pre-control of the SO2 content in the exhaust gas of the gas boiler through scientific detection and calculation; the method of the present invention has the characteristics of rapid measurement, high efficiency, high throughput and environmental protection; through the sulfur content adsorbed on the coke surface, combined with the sulfur element balance calculation model, the SO2 content in the exhaust gas of the gas boiler can be predicted in advance, so that the coke ratio structure can be optimized and adjusted in advance, ensuring that the SO2 content in the exhaust gas of the gas boiler is always kept under control, which has a positive promoting effect on maintaining a stable production level of the enterprise;

[0043] Moreover, the difference between the predicted value of SO2 content in the gas boiler exhaust gas obtained by the method of the present invention and the actually detected SO2 content in the gas boiler exhaust gas is relatively small. The predicted value obtained by the method of the present invention has the advantage of high accuracy and can be stably used as a basis for optimizing and adjusting the coke ratio structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the process of the present invention;

[0045] Figure 2 Schematic diagram of the destination of sulfur adsorbed on the coke surface in the method of the present invention. DETAILED DESCRIPTION

[0046] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0047] according to Figure 1-2 As shown, this embodiment proposes a method for calculating the SO2 content of exhaust gas from a gas-fired boiler that mainly burns blast furnace gas, comprising the following steps:

[0048] Step 1: Sample collection: Sample the incoming coke according to GB / T 1997-2008, the standard for the collection and preparation of coke samples;

[0049] Step 2: Preparation of standard samples. The coke samples collected in step 1 are subjected to two-stage screening, and the coke samples obtained after screening are used as standard coke samples. When performing the two-stage screening, sieves with 25mm×25mm and 40mm×40mm meshes are used to perform two-stage screening on the coke samples, and the coke samples with a particle size of 25mm-40mm obtained after screening are used as standard coke samples. In this embodiment, 1kg of coke samples with a particle size of 25mm-40mm are taken as standard coke samples;

[0050] Step 3: Detect the content of sulfur adsorbed on the surface of the standard coke sample. Soak 1 kg of the standard coke sample in 1 L of deionized water. After soaking for four hours, filter out the standard coke sample, and then take the soaking liquid for testing to detect the sulfur content.

[0051] In this embodiment, coke samples produced by 10 enterprises were taken to perform the above steps, and the sulfur content of the 10 groups was measured as shown in Table 1 below:

[0052] Table 1

[0053]

[0054]

[0055] Step 4: Convert the sulfur element form, and convert the sulfur element measured in step 3 into SO2 using formula (1);

[0056] M SO2 =(S)÷S(atomic weight)×(molecular weight) (1)

[0057] In formula (1), M SO2 is the amount of sulfur adsorbed on the surface of the standard coke sample and converted into boiler flue gas SO2, in mg / kg; (S) is the total sulfur content in the standard coke sample soaking solution, in mg / L; S (atomic weight) is the atomic weight of sulfur; SO2 (molecular weight) is the molecular weight of SO2;

[0058] In this embodiment, the sulfur content data detected in Table 1 is used to perform sulfur conversion, and the results shown in Table 2 are obtained:

[0059] Table 2

[0060] Suppliers unit ZGPM SHJS ZJT YNQ XCN PX XAY G JZ LLJ CYJ <![CDATA[M SO2 ]]> mg / kg 1021 646 866 577 626 725 1336 994 614 616

[0061] Step 5: Calculate the SO2 emission per ton of iron. Use formula (2) to calculate the SO2 emission per ton of iron.

[0062] Q SO2 =M SO2 × Focal ratio (2)

[0063] In formula (2), Q SO2 It is the SO2 emission per ton of iron, unit: mg / t·iron;

[0064] In this embodiment, according to the ten groups of M calculated in Table 2 SO2 The SO2 emission per ton of iron was calculated and the results are shown in Table 3 below:

[0065] Table 3

[0066] Suppliers unit ZGPM SHJS ZJT YNQ XCN PX XAY G JZ LLJ CYJ <![CDATA[Q SO2 ]]> mg / t·Fe 387950 245564 329050 219351 237834 275576 507786 377834 233381 234103

[0067] Step 6: Calculate the amount of coal gas generated per ton of iron. Use formula (3) to calculate the amount of coal gas generated per ton of iron.

[0068] Vg =C g ×22.4÷[12×((CO2)+(CO)+(CH4))] (3)

[0069] In formula (3), V g is the amount of gas per ton of iron, in m 3 / t; (CO2), (CO), (CH4) are the proportions of the corresponding components in the furnace top gas; C g The gasified carbon content per ton of pig iron, i.e., the amount of carbon present in the coal gas, is expressed in kg. g The calculation formula is shown in formula (7):

[0070] C g =K×(C) 焦 +M×(C) 煤 -C 尘 -C 渗 (7)

[0071] In formula (7), K and M are the coke ratio and coal ratio of blast furnace smelting, respectively, and the unit is kg / t; (C) 焦 (C) 煤 are the carbon content ratios of coke and coal powder respectively; C 尘 , C 渗 They are the carbon amount carried away by the furnace dust and the carbon amount carburized by the pig iron, in kg / t;

[0072] In this embodiment, the carbon content of coke in the coke samples provided by the 10 selected companies is shown in Table 4 below:

[0073] Table 4

[0074] Suppliers ZGPM SHJS ZJT YNQ XCN PX XAY G JZ LLJ CYJ <![CDATA[(C) 焦 %]]> 84.49 84.48 84.22 83.71 85.12 84.11 83.92 83.51 84.12 84.19

[0075] Tested: Pulverized coal injection in blast furnace (C) 煤 The carbon content is 74.43%; the volatile content of coke is 1.62%; the volatile content of pulverized coal injection is 18.0%;

[0076] Blast furnace coal ratio, blast furnace hot metal C 渗、 Blast furnace dry dust removal ash C 尘 , Gravity dust removal C 尘 , gravity dust removal ash amount, dry dust removal ash amount, and gas composition are taken as the average values ​​of the ten companies providing coke samples in the previous month. The specific parameters are shown in Table 5 below:

[0077] Table 5

[0078] Gravity dust removal capacity kg / t 7.69 <![CDATA[Dry dust removal carbon content C 尘 > 37％ Gas carbon monoxide content CO 24.10％ Dry dust removal capacity kg / t 6.39 <![CDATA[Carbon content C of gravity dust removal 尘 > 34％ <![CDATA[CO2 content in coal gas]]> 20.82％ Coal ratio kg / t 170 <![CDATA[Carbon content C in hot metal 渗 > 4.30％ <![CDATA[CH4 content in coal gas]]> 0.60％ <![CDATA[Hydrogen content H2 of coal gas]]> 3.46％

[0079] Then, according to the parameters in Table 5 above, the results of the coal gas volume per ton of iron calculated according to formula (3) are shown in Table 6 below:

[0080] Table 6

[0081] Suppliers ZGPM SHJS ZJT YNQ XCN PX XAY G JZ LLJ CYJ Coal gas volume per ton of iron m3 / t.Fe 1638 1638 1634 1626 1647 1632 1629 1623 1632 1633

[0082] Step 7: Calculate the burning time for 1m 3 The amount of air required for gas combustion is calculated using formula (4). 3 The amount of air required for gas;

[0083] L = α × L o (4)

[0084] L is complete combustion 1m 3 Actual air volume required for gas, m 3 ; L o For complete combustion 1m 3 Theoretical air volume required for gas, m 3 ; α is the excess air coefficient. Under complete combustion conditions, α takes the value of 1.05.

[0085] L o The calculation formula is shown in formula (8):

[0086] L o =(0.5(CO)+0.5(H2)+2(CH4)) / 21 (8)

[0087] L = α × L o =1.05×(0.5×24.10+0.5×3.46+2×0.6) / 21=0.749m 3

[0088] Step 8: Calculate the complete combustion of 1m 3 The flue gas produced by coal gas is calculated using formula (5) for complete combustion of 1m 3 The amount of smoke produced by coal gas;

[0089] V y =V CO2 +V H2O +V N2 +V O2 +V SO2 (5)

[0090] In formula (5), V y For complete combustion 1m 3 The amount of flue gas produced by coal gas, in m 3 ; V CO2 For complete combustion 1m 3 The amount of CO2 produced by coal gas, in m 3 ; V H2O For complete combustion 1m 3The amount of water vapor produced by coal gas, in m 3 ; V N2 For complete combustion 1m 3 The amount of N2 produced by coal gas, in m 3 ; V O2 For complete combustion 1m 3 The amount of O2 produced by coal gas, in m 3 ;

[0091] Among them, V CO2、 V H2O、 V N2和 V O2 The calculation formulas are shown in formulas (9), (10), (11), and (12) respectively:

[0092] V CO2 =0.01×((CO2)+(CO)+(CH4)) (9)

[0093] V H2O =0.01×((H2)+2(CH4)+(H2O)) (10)

[0094] V N2 =0.01×(N2)+0.79×L (11)

[0095] V O2 =0.21×(α-1)×L o。 (12)

[0096] Furthermore,

[0097] V y =0.01×(20.82+24.10+0.6)+0.01×(3.46+2×0.6)+0.01×(100-24.10-20.82-0.6-3.46)+0.79×0.749+0.21×(1.06-1)×0.749=1.613m 3 Step 9: Calculate the amount of SO2 in the flue gas of the gas-fired boiler when the ratio of blast furnace gas to converter gas is 9:1. Use formula (6) to calculate the amount of SO2 in the flue gas of the gas-fired boiler when the ratio of blast furnace gas to converter gas is 9:1.

[0098] C SO2 =Q SO2 ÷V y ×V g× 90% (6)

[0099] In formula (6), C SO2 is the amount of SO2 in boiler flue gas, in mg / m 3 ; 90% is the proportion of blast furnace gas in gas boilers;

[0100] (9) In this embodiment, using formula (6) C SO2 =Q SO2 ÷V y ×V g× 90%, the results of predicting the amount of SO2 in the flue gas of the power generation boilers after coking of each manufacturer are shown in Table 7 below:

[0101] Suppliers unit ZGPM SHJS ZJT YNQ XCN PX XAY G JZ LLJ CYJ <![CDATA[SO2 content in flue gas]]> mg / m3 125.20 79.25 106.45 71.29 76.32 89.23 164.71 123.01 75.57 75.75

[0102] According to the prediction results, the proportion of coke used by each manufacturer is controlled to ensure that the SO2 content in the flue gas of the power generation boiler is ≤100mg / m 3 The specific proportion of coke usage is shown in Table 8 below:

[0103] Table 8

[0104] Suppliers unit ZGPM SHJS ZJT YNQ XCN PX XAY G JZ LLJ CYJ total Ratio ％ 0％ 0％ 10％ 30％ 0％ 0％ 10％ 10％ 20％ 20％ 100％ <![CDATA[SO2 content in boiler flue gas]]> mg / m3 0.00 0.00 10.64 21.39 0.00 0.00 16.47 12.30 15.11 15.15 91.07

[0105] On the day of sampling, the actual value of SO2 content in boiler flue gas of 10 enterprises was monitored and the total result was 94.06 mg / m 3 The difference between the predicted total value of boiler flue gas SO2 content obtained by the method of the present invention and the total value is only 2.99 mg / m 3 .

[0106] The method of the present invention can realize the prediction and pre-control of the SO2 content in the exhaust gas of the gas boiler through scientific detection and calculation; the method of the present invention has the characteristics of rapid measurement, high efficiency, high throughput and environmental protection; through the sulfur content adsorbed on the coke surface, combined with the sulfur element balance calculation model, the SO2 content in the exhaust gas of the gas boiler can be predicted in advance, so that the coke ratio structure can be optimized and adjusted in advance, ensuring that the SO2 content in the exhaust gas of the gas boiler is always kept under control, which has a positive promoting effect on maintaining a stable production level of the enterprise;

[0107] Moreover, the difference between the predicted value of SO2 content in the gas boiler exhaust gas obtained by the method of the present invention and the actually detected SO2 content in the gas boiler exhaust gas is relatively small. The predicted value obtained by the method of the present invention has the advantage of high accuracy and can be stably used as a basis for optimizing and adjusting the coke ratio structure.

[0108] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for calculating the SO2 content of exhaust gas from a gas-fired boiler mainly mixed with blast furnace gas, characterized in that: The following steps are involved: Step 1: Sample collection: Sample the incoming coke according to GB / T 1997-2008, the standard for the collection and preparation of coke samples; Step 2: Preparation of standard samples: the coke samples collected in step 1 are subjected to two-stage screening, and the coke samples obtained after screening are used as standard coke samples; Step 3: Detecting the sulfur content adsorbed on the surface of the standard coke sample, soaking the standard coke sample, filtering it, collecting the soaking liquid, and measuring the sulfur content in the soaking liquid; Step 4: Convert the sulfur element form, and convert the sulfur element measured in step 3 into SO2 using formula (1); M SO2 =(S)÷S(atomic weight)×SO2(molecular weight) (1); In formula (1), M SO2 is the amount of sulfur adsorbed on the surface of the standard coke sample and converted into boiler flue gas SO2, in mg / kg; (S) is the total sulfur content in the standard coke sample soaking solution, in mg / L; S (atomic weight) is the atomic weight of sulfur; SO2 (molecular weight) is the molecular weight of SO2; Step 5: Calculate the SO2 emission per ton of iron. Use formula (2) to calculate the SO2 emission per ton of iron. Q SO2 =M SO2 × focal ratio (2); In formula (2), Q SO2 is the SO2 emission per ton of iron; Step 6: Calculate the amount of coal gas generated per ton of iron. Use formula (3) to calculate the amount of coal gas generated per ton of iron. V g =C g ×22.4÷[12×((CO2)+(CO)+(CH4))] (3); In formula (3), V g is the amount of coal gas per ton of iron, in m 3 / t; (CO2), (CO), (CH4) are the proportions of the corresponding components in the furnace top gas; C g The amount of gasified carbon per ton of pig iron, that is, the amount of carbon present in the coal gas, in kg; The gasified carbon content C g The calculation formula is shown in formula (7): C g =K×(C) 焦 +M×(C) 煤 -C 尘 -C 渗 (7); In formula (7), K and M are the coke ratio and coal ratio of blast furnace smelting, respectively, and the unit is kg / t; (C) 焦 、(C) 煤 are the carbon content ratios of coke and coal powder respectively; C 尘 , C 渗 They are the carbon amount carried away by the furnace dust and the carbon amount carburized by the pig iron, in kg / t; Step 7: Calculate the burning time for 1m 3 The amount of air required for gas combustion is calculated using formula (4). 3 The amount of air required for gas; L=α×L o (4); In formula (4), L is the total combustion of 1m 3 Actual air volume required for gas; L o For complete combustion 1m 3 The theoretical amount of air required for gas; α is the excess air coefficient. Under complete combustion conditions, α is 1.05; L o The calculation formula is shown in formula (8): L o =(0.5(CO)+0.5(H2)+2(CH4)) / 21 (8); Step 8: Calculate the complete combustion of 1m 3 The flue gas produced by coal gas is calculated using formula (5) for complete combustion of 1m 3 The amount of smoke produced by coal gas; V y =V CO2 +V H2O +V N2 +V O2 +V SO2 (5) In formula (5), V y For complete combustion 1m 3 The amount of flue gas produced by coal gas, in m 3 ; V CO2 For complete combustion 1m 3 The amount of CO2 produced by coal gas, in m 3 ; V H2O For complete combustion 1m 3 The amount of water vapor produced by coal gas, in m 3 ; V N2 For complete combustion 1m 3 The amount of N2 produced by coal gas, in m 3 ; V O2 For complete combustion 1m 3 The amount of O2 produced by coal gas, in m 3 ; Among them, V CO2、 V H2O、 V N2和 V O2 The calculation formulas are shown in formulas (9), (10), (11), and (12) respectively: IN CO2 =0.01×((CO2)+(CO)+(CH4)) (9); V H2O =0.01×((H2)+2(CH4)+(H2O)) (10); In N2 =0.01×(N2)+0.79×L (11); V O2 =0.21×(α -1)×L o (12); Step 9: Calculate the amount of SO2 in the flue gas of the gas-fired boiler when the ratio of blast furnace gas to converter gas is 9:

1. Use formula (6) to calculate the amount of SO2 in the flue gas of the gas-fired boiler when the ratio of blast furnace gas to converter gas is 9:

1. C SO2 =Q SO2 ÷V y ×V g ×90% (6); In formula (6), C SO2 is the amount of SO2 in boiler flue gas, in mg / m 3 ; 90% is the proportion of blast furnace gas blended into gas boilers.

2. The method for calculating the SO2 content of exhaust gas from a gas-fired boiler mainly mixed with blast furnace gas according to claim 1, characterized in that: When the coke sample is subjected to two-stage screening in the step 2, sieves with 25mm×25mm and 40mm×40mm meshes are used to perform two-stage screening on the coke sample, and the coke sample with a particle size of 25mm-40mm obtained after screening is used as the standard coke sample.

3. The method for calculating the SO2 content of exhaust gas from a gas-fired boiler mainly blended with blast furnace gas according to claim 1, characterized in that: The specific operation of detecting the content of sulfur adsorbed on the surface of the standard coke sample in step 3 is: soaking the standard coke sample in deionized water, filtering out the standard coke sample after soaking for four hours, and then taking the soaking liquid for testing to detect the sulfur content.

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