Method for controlling the amount of calcium powder used in flue gas desulfurization of dry quenching

Abstract

The present application relates to a kind of methods for controlling dry quenching flue gas desulfurization calcium powder dosage, according to coke composition, CO2, CO in flue gas CO2 / CO Volume ratio, the air volume consumed by coke combustion is calculated;According to coke composition and the air volume consumed by combustion, further calculate the flue gas volume and flue gas volume / air volume coefficient;According to the flue gas volume and oxygen content variation, based on oxygen balance, the combustion air volume increased during coke loading process is calculated;Utilize the air volume involved in combustion during non-coke loading and coke loading, the air volume consumed by coke combustion, calculate the coke combustion rate;Utilize the coke combustion rate and coke sulfur content, calculate the flue gas SO2 generation rate;According to the effective content of calcium powder Ca (OH) 2 and calcium powder utilization rate, under the premise of setting SO2 removal rate, the calcium powder dosage during non-coke loading and coke loading is calculated respectively.The present application realizes the accurate control of desulfurization calcium powder dosage in different operation stages, and reduces the error caused by artificial adjustment.

Description

TECHNICAL FIELD

[0001] The application relates to a method for controlling the amount of calcium powder used in dry quenching flue gas desulfurization, and belongs to the technical field of dry quenching flue gas treatment. BACKGROUND

[0002] Dry quenching flue gas needs to be desulfurized so that SO2 and particulate matter can be discharged after reaching the standard. With the conversion of coke loading and non-coke loading operations, the dry quenching flue gas flow and SO2 concentration are significantly intermittent and fluctuate greatly, making it difficult to accurately control the amount of desulfurizing agent in actual production.

[0003] The patent with the publication number CN208244396U, a device for reducing the sulfur dioxide of the chimney of a dry quenching environment ground dust removal system, solves the problem of sulfur dioxide emission exceeding the standard by connecting the dry quenching flue gas to the coke oven flue gas desulfurization system through a pipeline.

[0004] The patent with the publication number CN209276442U, a dry quenching pre-storage section circulating flue gas desulfurization and dust removal purification system, mixes dry quenching pre-storage section circulating flue gas with high SO2 concentration with coke oven flue gas, and then uses a coke oven flue gas desulfurization and denitrification device to achieve flue gas purification.

[0005] The patent with the publication number CN215276253U, a dry quenching desulfurization and dust removal device for a coking plant, discloses a dry quenching desulfurization device that has a separate spray desulfurization tower.

[0006] The patent application with the publication number CN113828129A, a high-efficiency dry quenching desulfurizing agent and application, discloses a high-efficiency dry quenching desulfurizing agent composed of multiple substances, which can achieve deep desulfurization of dry quenching flue gas.

[0007] The use of high-activity calcium powder for dry quenching flue gas desulfurization is a new technology that has emerged in recent years, and there are few published research reports. Among the existing dry quenching flue gas desulfurization technologies: some (such as the patents with the publication numbers CN208244396U and CN209276442U) focus on directing dry quenching flue gas into other desulfurization devices for treatment. This method not only increases the load of the original desulfurization device, but also greatly impacts the operation control of the original device due to the large fluctuations in dry quenching flue gas flow and pollutant load. Another part (such as the patent with the publication number CN215276253U) separately constructs a dry quenching desulfurization device. The construction and operation costs of these technologies are relatively high, and they can be considered for new plant sites, but they cannot be implemented in existing plant sites. Moreover, the above-mentioned technical solutions are only theoretically feasible, but in order to achieve ideal purification results, many process factors still need to be explored and considered comprehensively, and they cannot be applied to different working conditions.

[0008] In view of the above reasons, in recent years, the technology of directly spraying desulfurizer in the dry quenching flue has gradually increased, and the desulfurizer used is mainly divided into sodium-based and calcium-based. The sodium-based desulfurizer is mainly baking soda, the desulfurization effect of the desulfurizer is good, but the reaction temperature requirement is high, and the product is difficult to handle, so the application of the technology is limited. The calcium-based desulfurizer is mainly calcium oxide or calcium hydroxide, because its applicable temperature range is larger, and the desulfurization product is easier to handle, so it is more and more used.

[0009] Although the calcium-based desulfurization method has become the main technology of dry quenching flue gas desulfurization, there is almost no report on the control method related to the calcium powder consumption at present, especially the control method considering the intermittent characteristics of dry quenching flue gas.

[0010] In view of the deficiencies in the prior art, the present application provides a method for accurately controlling the consumption of desulfurizing calcium powder in different operation stages by using the existing detection data of the dry quenching system without adding new detection equipment. SUMMARY

[0011] In order to solve the above problems, the present application discloses a method for controlling the consumption of dry quenching flue gas desulfurizing calcium powder, and the specific technical scheme is as follows:

[0012] A method for controlling the consumption of dry quenching flue gas desulfurizing calcium powder, comprising the following steps:

[0013] Step (1) calculating the air consumption of coke combustion according to the coke composition, the volume ratio of CO2 / CO in the dry quenching flue gas, CO2 and CO;

[0014] Step (2) further calculating the flue gas quantity after combustion and the coefficient of flue gas quantity after combustion / air consumption of coke combustion according to the coke composition and the air consumption of coke combustion calculated in step (1);

[0015] Step (3) calculating the increased combustion air quantity during the charging process based on oxygen balance according to the flue gas quantity after combustion and the oxygen content change;

[0016] Step (4) calculating the coke combustion rate by using the air quantity participating in combustion during non-charging and charging, and the air consumption of coke combustion;

[0017] Step (5) calculating the SO2 generation rate in the flue gas after combustion by using the coke combustion rate and the sulfur mass content in the coke;

[0018] Step (6) calculating the calcium powder consumption during non-charging and charging respectively under the set SO2 removal rate according to the effective content of calcium powder Ca(OH)2 and the calcium powder utilization rate, and then controlling the calcium powder consumption in stages.

[0019] Further, the calculation process of step (1) is:

[0020] The air consumption of coke combustion is the sum of the air consumption of each element in coke, and the element composition of air consumption in coke combustion includes C, H and S, wherein the reaction of carbon and oxygen includes complete combustion to generate CO2 and incomplete combustion to generate CO, and the oxygen consumption of C element in coke is calculated according to the volume ratio of CO2 and CO in flue gas and chemical equation; H and S are finally changed into H2O and SO2 in the combustion process, and the oxygen consumption of H and S elements is calculated by chemical equation; according to the oxygen content of air being 21%, the air consumption calculation formula of coke combustion is derived by simplifying,

[0021] ,

[0022] In the formula, V ca is the air consumption of coke combustion, m 3 / kg; C%, H% and S% are the mass percentage contents of carbon, hydrogen and sulfur elements in coke, respectively; C rate is the volume ratio of CO2 and CO in flue gas.

[0023] Further, the calculation process of step (2) is: the flue gas generated by coke combustion includes the flue gas generated after the combustion of each element in coke and the remaining nitrogen gas after the combustion of air, and the calculation formula is,

[0024] ,

[0025] In the formula, V cf is the flue gas volume generated by coke combustion, m 3 / kg; N% is the mass percentage content of nitrogen element in coke;

[0026] The flue gas volume / air volume coefficient is the volume ratio of the flue gas volume generated after coke combustion to the air consumption of coke combustion, and the calculation formula is,

[0027] ,

[0028] In the formula, C o is the volume ratio of the flue gas volume generated after coke combustion to the air consumption of combustion.

[0029] Further, the calculation process of step (3) is:

[0030] Air is sucked in during coke charging, part of the air does not participate in chemical reaction, and is directly mixed with flue gas and discharged, and part of the air participates in combustion reaction to increase coke loss;

[0031] According to the changes of flue gas volume and oxygen content during coke charging and non-coke charging, the mixed air volume sucked in during coke charging is calculated by oxygen balance, and the calculation formula is,

[0032] ,

[0033] V0=V1-O1 mix is the mixed air volume sucked in during the coking process, m 3 / h; V1, O1 are the flue gas volume and oxygen content during the coking process; V0, O0 are the flue gas volume and oxygen content during the non-coking process.

[0034] Further, the combustion-supporting air volume increased during the coking process is calculated by the formula,

[0035] ,

[0036] V1=V0+V b is the combustion-supporting air volume increased during the coking process, m 3 / h.

[0037] Further, the calculation process of the step (4) is as follows:

[0038] The air volume participating in the combustion during the non-coking process is the circulating gas air supplement volume, and the air volume participating in the combustion during the coking process is the sum of the circulating gas supplement volume and the combustion-supporting air volume increased during the coking process, thus,

[0039] ,

[0040] Coke0=V0 / C0 a is the circulating gas air supplement volume, m 3 / h; Coke1 is the coke combustion rate during the coking process.

[0041] Further, the calculation process of the step (5) is as follows: the SO2 in the flue gas is derived from the combustion of sulfur elements in the coke, the S contained in the coke is changed into SO2 entering the flue gas, the molecular weight of S is 32, and the molecular weight of SO2 is 64, thus the SO2 generation rate is twice the S element in the coke, the sulfur content in the coke is: coke mass ✖ sulfur percentage content ✖ 2, thus the SO2 generation rates of the flue gas during the non-coking and coking processes are

[0042] , Further simplification obtains the calculation formula,

[0043] ,

[0044] S0=V0 / C0

[0045] Further, the desulfurization reaction equation is SO2+Ca(OH)2+0.5O2=CaSO4+H2O, the effective content of Ca(OH)2 in calcium powder and the calcium powder utilization rate are determined through sample detection and data statistics, the calcium powder consumption is calculated in combination with the SO2 generation rate of flue gas under the premise of setting the SO2 removal rate, and the calculation formula is,

[0046] ,

[0047] In the formula, AM0 is the calcium powder consumption during non-coke charging, kg / h; AM1 is the calcium powder consumption during coke charging, kg / h; Dr is the SO2 removal rate; Ca% is the effective content of Ca(OH)2 in calcium powder; Eff is the calcium powder utilization rate, 64 is the molecular weight of SO2, and 74 is the molecular weight of Ca(OH)2.

[0048] The present application has the following beneficial effects:

[0049] The present application makes full use of the basic detection data of the existing dry quenching system, and realizes precise control of the desulfurization calcium powder consumption in different operation stages without adding new equipment.

[0050] The present application is convenient for realizing programmed and online control, and reduces the operation errors caused by human adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is a flowchart of the present application.

[0052] Figure 2 is a calcium powder consumption control curve of the present application. DETAILED DESCRIPTION

[0053] The present application will be further illustrated below in combination with the drawings and specific embodiments. It should be understood that the following specific embodiments are only used for illustrating the present application and are not used for limiting the scope of the present application.

[0054] In combination with the drawings, Figure 1 It can be seen that the method for controlling the calcium powder consumption of dry quenching flue gas desulfurization of the present application has the following detailed technical solutions:

[0055] 1. The air consumption consumed by coke combustion is calculated according to the volume ratio CO2 / CO of CO2 and CO in flue gas, and the coke components including the contents of C, H, N and S.

[0056] The air consumption of coke combustion is the sum of the air mass consumed by each element in coke, mainly including C, H, and S, and other elements basically do not consume or only consume a little air which can be ignored. Carbon reacts with oxygen including two kinds of complete combustion to generate CO2 and incomplete combustion to generate CO. According to the volume ratio of CO2 and CO in flue gas and chemical equation, the oxygen consumption of C element in coke is calculated; H and S are finally changed into H2O and SO2 in the combustion process, and the oxygen consumption of H and S elements is calculated through chemical equation. According to the oxygen content of air being 21%, the air consumption calculation formula of coke combustion is derived by simplifying as follows,

[0057] ,

[0058] In the formula, V ca is the air consumption of coke combustion, m 3 / kg; C%, H%, and S% are the mass percentage contents of carbon, hydrogen, and sulfur elements in coke, respectively; C rate is the volume ratio of CO2 and CO in flue gas.

[0059] The derivation process of formula (1) is as follows:

[0060] C, H, and S in coke consume O2 in the combustion process.

[0061] ①Calculate the air consumption of carbon element gasification in 1 kg of coke

[0062] Carbon element gasification includes two reactions of complete combustion reaction 1: C+O2=CO2 and incomplete combustion reaction 2: 2C+O2=2CO, and the oxygen consumptions of the two reactions are different.

[0063] The volume ratio of CO2 and CO in flue gas is C rate , and the coke consumption percentage of the first reaction and the second reaction is a1 and a2 respectively, then the balance equation is

[0064] ,

[0065] Solving the above two equations, we can get , .

[0066] Further calculation of the air consumptions (oxygen content is 21%) of reaction 1 and reaction 2 are respectively,

[0067] ,

[0068] ,

[0069] The sum of the two is the air consumption of carbon element, and the sum is simplified as

[0070] ,

[0071] ②Calculate the air consumption of hydrogen element gasification in 1 kg of coke

[0072] The chemical reaction is 2H2+O2=2H2O, the mass of hydrogen element is H% kg, and the air consumption is

[0073] ,

[0074] ③Calculate the air consumption of S element gasification in 1 kg of coke

[0075] The chemical reaction is S+O2=SO2, the mass of sulfur element is S% kg, and the air consumption is

[0076] ,

[0077] ①+②+③ is the air consumption of 1 kg of coke combustion, and the formula (1) is obtained by combining and simplifying

[0078] .

[0079] 2、According to the composition of coke and the air consumption V ca Further calculate the flue gas volume and the flue gas volume / air volume coefficient. The flue gas volume generated by coke combustion includes the flue gas generated by the combustion of each element in coke and the remaining nitrogen after air combustion, and the calculation formula is,

[0080] ,

[0081] In the formula: V cf is the flue gas volume generated by coke combustion, m 3 / kg; N% is the mass percentage of nitrogen element in coke.

[0082] The flue gas volume / air volume coefficient is the volume ratio of the flue gas volume generated by coke combustion to the air consumption, and the calculation formula is,

[0083] ,

[0084] In the formula: C o is the volume ratio of the flue gas volume generated by coke combustion to the air consumption.

[0085] The elements C, H, N, S in coke will become gas and produce flue gas after combustion, among which C element becomes CO2 and CO, H element becomes H2O, N element becomes N2, and S element becomes SO2. Theoretically, O2 in the combustion air is consumed, and the remaining N2 also enters the flue gas. Therefore, the flue gas volume generated by coke combustion is: .

[0086] The volume of C element after gasification is ,

[0087] The volume of H element after gasification is ,

[0088] The volume of N element after gasification is ,

[0089] The volume of S element after gasification is ,

[0090] The remaining N2 volume after the combustion-supporting air O2 is exhausted is 0.79xV ca .

[0091] The above items are added and simplified to obtain formula (2)

[0092] .

[0093] 3. According to the changes of flue gas volume and oxygen content, the increased combustion-supporting air volume during the coke charging process is calculated based on oxygen balance.

[0094] Air is sucked in during the coke charging process. Part of the air does not participate in the chemical reaction, is directly mixed with the flue gas and is discharged, and part of the air participates in the combustion reaction to increase the coke burn-off.

[0095] According to the changes of flue gas volume and oxygen content during the coke charging and non-coke charging periods, the mixed air volume sucked in during the coke charging process is calculated using oxygen balance, and the calculation formula is

[0096] ,

[0097] In the formula, V mix is the mixed air volume sucked in during the coke charging process, m 3 / h; V1 and O1 are the flue gas volume and oxygen content during the coke charging period; V0 and O0 are the flue gas volume and oxygen content during the non-coke charging period.

[0098] The increased combustion-supporting air volume during the coke charging process is further calculated, and the calculation formula is

[0099] ,

[0100] In the formula, V b is the increased combustion-supporting air volume during the coke charging process, m 3 / h.

[0101] The mixed air volume sucked in during the coke charging process is derived by oxygen balance (the air oxygen content percentage is 21),

[0102] The total oxygen of flue gas during coke charging = total oxygen of non-coke charging flue gas + oxygen content of mixed air, and the formula can be expressed as:

[0103] ,

[0104] Simplify the derivation to obtain formula (4)

[0105] ,

[0106] According to the flue gas volume balance, the following relationship exists:

[0107] The flue gas volume during coke charging = the non-coke charging flue gas volume + the mixed air volume + the newly added coke combustion flue gas volume,

[0108] The newly added coke combustion flue gas volume can be represented by the “combustion air volume ✕ the volume ratio of the flue gas volume generated by coke combustion to the consumed air volume”, that is, V b *C0, so this balance can be represented by formula

[0109] ,

[0110] After transformation, formula (5) is obtained,

[0111] .

[0112] 4. The air volume participating in combustion during non-coke charging and coke charging, and the air volume consumed by coke combustion are used to calculate the coke combustion rate. The air volume participating in combustion during non-coke charging is the circulating gas air supplement volume, and the air volume participating in combustion during coke charging is the sum of the circulating gas supplement volume and the combustion-supporting air volume increased during the coke charging process. Therefore,

[0113] ,

[0114] In the formula: Coke0 is the coke combustion rate during non-coke charging, kg / h; V a is the circulating gas air supplement volume, m 3 / h; Coke1 is the coke combustion rate during coke charging.

[0115] The air consumed by coke combustion during non-coke charging is the circulating gas air supplement volume V a , so the coke combustion rate is obtained by dividing the circulating air supplement volume by the air consumed by coke combustion, and formula (6) is obtained

[0116] ,

[0117] The air consumed by coke combustion during coke charging is the circulating gas supplement volume Va plus the combustion-supporting air volume V b increased during the coke charging process, so the coke combustion rate is obtained by dividing the sum of the circulating air supplement volume and the combustion-supporting air volume increased during the coke charging process by the air consumed by coke combustion, and formula (7) is obtained

[0118] ,

[0119] 5. SO2 in flue gas originates from the combustion of sulfur in coke. Therefore, the SO2 generation rate in flue gas can be calculated using the coke combustion rate and coke sulfur content. The calculation formula is as follows:

[0120] ,

[0121] In the formula: S0 is the SO2 generation rate of flue gas during the non-coking process, kg / h; S1 is the SO2 generation rate of flue gas during the coking process, kg / h.

[0122] When burning coke, sulfur (S) is converted into SO2 and enters the flue gas. The molecular weight of sulfur is 32, while the molecular weight of SO2 is 64. Therefore, the SO2 generation rate is twice that of sulfur in the burning coke.

[0123] The sulfur content in coke is calculated as: coke mass × sulfur percentage × 2. Therefore, the SO2 generation rate in the flue gas during the non-coke loading process is:

[0124] Further simplification yields formula (8).

[0125] ,

[0126] The derivation process of formula (9) is the same as that of formula (8).

[0127] 6. Determine the effective Ca(OH)2 content and utilization rate of calcium powder through sample testing and data statistics. Under the premise of setting the SO2 removal rate, calculate the amount of calcium powder used based on the SO2 generation rate in the flue gas. The calculation formula is as follows:

[0128] ,

[0129] In the formula: AM0 is the amount of calcium powder used during non-coke loading period, kg / h; AM1 is the amount of calcium powder used during coke loading, kg / h; Dr is the SO2 removal rate; Ca% is the effective content of Ca(OH)2 in the calcium powder; Eff is the utilization rate of calcium powder.

[0130] The desulfurization reaction equation is SO2+Ca(OH)2+0.5O2=CaSO4+H2O, where SO2 has a molecular weight of 64 and Ca(OH)2 has a molecular weight of 74. Equations (10) and (11) can be obtained through reaction equilibrium.

[0131] During non-coke loading periods, the calcium powder usage is controlled at AM0; during coke loading, the calcium powder usage is adjusted to AM1. Further consideration is given to the coke loading cycle and cap opening time to determine the calcium powder usage control curve. Figure 2 As shown.

[0132] Three specific examples of the present application are given below:

[0133] Example 1

[0134] 1, The percentage content of carbon, hydrogen and sulfur in the coke is C%=86, H%=0.2, S%=0.85, and the volume ratio of CO2 and CO in the flue gas after coke combustion is 9. According to formula (1), the air consumption V of coke combustion is calculated ca = 7.08 m 3 / kg.

[0135] 2, The percentage content of nitrogen in the coke is N%=0.8, and the flue gas volume V generated by coke combustion is calculated by substituting the content of various elements in the coke into formula (2) cf = 7.23 m 3 / kg, and further the flue gas volume / air volume coefficient Co is calculated according to formula (3) Co=1.02.

[0136] 3, According to the online monitoring data of flue gas, the flue gas volume V0 during non-coke charging is 60100 m 3 / h, the oxygen content O0 is 17.5, the flue gas volume V1 during coke charging is 144000 m 3 / h, and the oxygen content O1 is 18.3. The mixed air volume V mix = 75402 m 3 / h is calculated by formula (4) during the coke charging process, and further the increased combustion air volume V b = 8331 m 3 / h is calculated by formula (5) during the coke charging process.

[0137] 4, The coke combustion rate is calculated using the air volume involved in combustion during non-coke charging and coke charging, and the air volume consumed by coke combustion. The air volume involved in combustion during non-coke charging is the circulating gas air supplement, and the air volume involved in combustion during coke charging is the sum of the circulating gas supplement and the increased combustion air volume during the coke charging process. The circulating air supplement V a = 6000 m 3 / h, the coke combustion rate Coke0 during non-coke charging is calculated according to formula (6) as 847 kg / h, and the coke combustion rate Coke1 during coke charging is calculated according to formula (7) as 2024 kg / h.

[0138] 5, SO2 in the flue gas is derived from the combustion of sulfur elements in the coke, so the SO2 generation rate of the flue gas is calculated using the coke combustion rate and the sulfur content of the coke. Substituting Coke0=847 kg / h, Coke1=2023 kg / h, S%=0.85 into formula (8) and (9) respectively, the SO2 generation rates of the flue gas during non-coke charging and coke charging are S0=14.4 kg / h and S1=34.4 kg / h respectively.

[0139] 6. The effective content of Ca(OH)2 and the utilization rate of calcium powder are Ca%=90% and Eff=20%, respectively. The expected SO2 removal rate Dr=80%. According to formula (10), the calcium powder usage during non-coke loading period is calculated to be AM0=74.0kg / h. According to formula (11), the calcium powder usage during coke loading period is calculated to be AM1=176.8kg / h. The calcium powder usage during non-coke loading period is controlled at AM0, and the calcium powder usage during coke loading is adjusted to AM1. Further, the calcium powder usage is determined by combining the coke loading cycle and the opening time. Figure 2 The calcium powder dosage control curve is shown.

[0140] Example 2

[0141] 1. The percentage contents of carbon, hydrogen, and sulfur in coke are C%=85.8%, H%=0.22%, and S%=0.75, respectively. The volume ratio of CO2 to CO in the flue gas after coke combustion is 3. Calculate the air consumption V for coke combustion according to formula (1). ca =6.24m 3 / kg.

[0142] 2. The nitrogen content in coke is N% = 0.75. Substitute the contents of various elements in coke into formula (2) to calculate the amount of flue gas V produced by coke combustion. cf = 6.57m 3 / kg, further calculate the flue gas volume / air volume coefficient C according to formula (3). o =1.05.

[0143] 3. According to online flue gas monitoring data, the flue gas volume during non-coke loading period is V0 = 50500 m³ / h. 3 / h, oxygen content O0=16.4, flue gas volume during coking V1=114000m³ 3 / h, oxygen content O1=17.6. The amount of mixed air V drawn in during the coking process is calculated using formula (4). mix =56105m 3 / h, further calculate the increased combustion air volume V during the coking process using formula (5). b =7042m 3 / h.

[0144] 4. Calculate the coke combustion rate using the amount of air involved in combustion during both the non-coke loading and coke loading periods, and the amount of air consumed by coke combustion. The amount of air involved in combustion during the non-coke loading period is the amount of recirculated gas supplementary air; the amount of air involved in combustion during the coke loading period is the sum of the recirculated gas supplementary air and the amount of combustion-supporting air added during the coke loading process. The recirculated air supplementary air amount V... a =5400m 3= 865 kg / h and the coke burning rate during the coke charging Cokei = 1994 kg / h according to equation (7).

[0145] 5. SO2 in the flue gas comes from the burning of sulfur element in the coke, so the flue gas SO2 production rate is calculated by the coke burning rate and the coke sulfur content. Substituting Cokeo = 865 kg / h, Cokei = 1994 kg / h, S% = 0.75 into equation (8) and (9) respectively, the flue gas SO2 production rate during non-coke charging and coke charging is S0= 13.0 kg / h, Si = 29.9 kg / h respectively.

[0146] 6. The effective content of Ca(OH)2 in the calcium powder and the calcium powder utilization rate are Ca% = 91%, Eff = 25% respectively, and the expected SO2 removal rate Dr = 90% is set, the calcium powder consumption AM0= 59.5 kg / h during non-coke charging is calculated according to equation (10), and the calcium powder consumption AMi = 136.8 kg / h during coke charging is calculated according to equation (11). The calcium powder consumption is controlled as AM0during non-coke charging, and the calcium powder consumption is adjusted as AMi during coke charging, further combined with the coke charging period and the uncovering time to determine the calcium powder consumption control curve as shown in FIG. 1, wherein the uncovering time is the coke charging section, and the covering time is the non-coke charging section. Figure 2

[0147] Example 3

[0148] 1. The percentage contents of carbon, hydrogen and sulfur in the coke are C% = 85.2, H% = 0.19, S% = 0.91 respectively, and the volume ratio of CO2 and CO in the flue gas after the coke burning is 5. The air volume V ca = 6.62 m 3 / kg consumed by the coke burning is calculated according to equation (1).

[0149] 2. The percentage content of nitrogen in the coke is N% = 1.11, and the flue gas volume V cf = 6.86 m 3 / kg produced by the coke burning is calculated by substituting the contents of various elements in the coke into equation (2), and further the flue gas volume / air volume coefficient C o = 1.02 is calculated according to equation (3).

[0150] 3. According to the online monitoring data of the flue gas, the flue gas volume V0= 45600 m 3 / h during non-coke charging, and the oxygen content O0= 17.2, the flue gas volume V1= 109000 m 3 / h during coke charging, and the oxygen content Oi = 17.6. The mixed air volume V mix = 54004 m​3 Further, the combustion air amount V added during the coke charging process is calculated using equation (5) b = 9035 m 3 / h.

[0151] 4. The coke combustion rate is calculated using the air amount participating in combustion during non-coke charging and coke charging, and the air amount consumed by coke combustion. The air amount participating in combustion during non-coke charging is the circulating gas air make-up amount, and the air amount participating in combustion during coke charging is the sum of the circulating gas make-up amount and the combustion air amount added during the coke charging process. The circulating air make-up amount V a = 6200 m 3 / h. The coke combustion rate Cokeo during non-coke charging is calculated as 937 kg / h according to equation (6), and the coke combustion rate Cokei during coke charging is calculated as 2301 kg / h according to equation (7).

[0152] 5. The SO2 in the flue gas is derived from the combustion of sulfur elements in the coke, so the flue gas SO2 generation rate is calculated using the coke combustion rate and the coke sulfur content. Substituting Cokeo = 937 kg / h, Cokei = 2301 kg / h, and S% = 0.91 into equations (8) and (9) respectively, the flue gas SO2 generation rates during non-coke charging and the coke charging process are S0 = 17.1 kg / h and Si = 41.9 kg / h respectively.

[0153] 6. The effective content of Ca(OH)2 in the calcium powder and the calcium powder utilization rate are Ca% = 90% and Eff = 20% respectively, and the expected SO2 removal rate Dr is set as 80%. The calcium powder consumption AMo during non-coke charging is calculated as 87.9 kg / h according to equation (10), and the calcium powder consumption AMi during coke charging is calculated as 215.3 kg / h according to equation (11). The calcium powder consumption is controlled as AMo during non-coke charging, and the calcium powder consumption is adjusted as AMi during coke charging, and further combined with the coke charging period and the uncovering time to determine the calcium powder consumption control curve as shown in Figure 2 .

[0154] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have meanings consistent with those in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless otherwise defined.

[0155] With the above ideal embodiments according to the present application as the inspiration, through the above description, relevant staff can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. A method for controlling the amount of calcium powder used in dry quenching flue gas desulfurization, characterized by, The method comprises the following steps: Step (1) calculating the air consumption of coke combustion according to the coke composition, the volume ratio of CO2 to CO in dry quenching flue gas, the calculation process being: The air consumption of coke combustion is the sum of the air consumption of each element in coke, and the element composition of air consumption in coke includes C, H and S, wherein the reaction of carbon and oxygen includes complete combustion to generate CO2 and incomplete combustion to generate CO, the oxygen consumption of C element in coke is calculated according to the volume ratio of CO2 to CO in flue gas and the chemical equation; H and S are finally changed into H2O and SO2 in the combustion process, and the oxygen consumption of H and S elements is calculated through the chemical equation; according to the oxygen content of 21% in air, the air consumption calculation formula of coke combustion is derived through simplification, （1） wherein: V ca is the air consumption for coke combustion, m 3 / kg; C%, H%, S% are the mass percentage of carbon, hydrogen, and sulfur in the coke, respectively; C rate is the volume ratio of CO2, CO in the flue gas; Step (2) further calculating the flue gas quantity after combustion and the coefficient of flue gas quantity after combustion to air consumption according to the coke composition and the air consumption of coke combustion calculated in step (1), the calculation process being: the flue gas generated by coke combustion includes the flue gas generated after the combustion of each element in coke and the nitrogen remaining after the combustion of air, and the calculation formula being, （2） wherein: V cf is the amount of flue gas generated by the coke combustion, m 3 / kg; N% is the mass percentage of nitrogen element in the coke; The flue gas / air quantity coefficient is the volume ratio of the flue gas quantity after coke combustion to the air consumption of coke combustion, and the calculation formula being, （3） In the formula: C o is the volume ratio of the amount of flue gas generated after the coke is burned to the amount of air consumed for burning; Step (3) calculating the increased combustion-supporting air quantity in the coke charging process based on oxygen balance according to the flue gas quantity after combustion and the oxygen content change, the process being: Air is sucked in during the coke charging process, part of the air does not participate in the chemical reaction, is directly mixed with the flue gas and is discharged, and part of the air participates in the combustion reaction to increase the coke burn loss; The mixed air quantity sucked in during the coke charging process is calculated by oxygen balance according to the flue gas quantity and the oxygen content change during the coke charging and non-coke charging periods, and the calculation formula being, （4） wherein: V mix V0+ V1= V 3 V0+ V1= V V0+ V1= V The increased combustion-supporting air quantity in the coke charging process is further calculated, and the calculation formula being, (5) where: V b m is the amount of combustion air added for the focusing process, m 3 / h; Step (4) calculating the coke combustion rate by using the air quantity participating in combustion during non-coke charging and coke charging and the air consumption of coke combustion, the process being: The air quantity participating in combustion during non-coke charging is the air supplement quantity of circulating gas, the air quantity participating in combustion during coke charging is the sum of the circulating gas supplement quantity and the increased combustion-supporting air quantity in the coke charging process, and therefore, （6） （7） wherein: Coke0 is the coke burn rate during non-coke charging, kg / h; V a is the make-up air rate for the recycle gas, m 3 / h; Coke1 is the coke burn rate during coke charging; Step (5) calculates the SO2 production rate in the flue gas after combustion by using the coke combustion rate and the sulfur mass content in the coke. The process is as follows: the SO2 in the flue gas comes from the combustion of sulfur elements in the coke. The S contained in the coke becomes SO2 and enters the flue gas. The molecular weight of S is 32, and the molecular weight of SO2 is 64. Therefore, the SO2 production rate is twice the S element in the coke. The sulfur content in the coke is: coke mass Sulfur content 2, thus obtaining the SO2 production rate of the flue gas in the non-coke charging and coke charging processes: , , further simplifying, we get the calculation formula as, （8） （9） In the formula, S0 is the SO2 generation rate of flue gas during non-coke charging, kg / h; S1 is the SO2 generation rate of flue gas during coke charging, kg / h; Step (6) calculating the calcium powder quantity during non-coke charging and coke charging respectively according to the effective content of calcium powder Ca(OH)2 and the calcium powder utilization rate under the set SO2 removal rate, and then controlling the calcium powder quantity in stages, the desulfurization reaction equation being SO2+Ca(OH)2+0.5O2=CaSO4+H2O, the effective content of Ca(OH)2 in calcium powder and the calcium powder utilization rate are determined through sample detection and data statistics, the calcium powder quantity is calculated under the premise of the set SO2 removal rate, and the calculation formula being, （10） （11） In the formula: AM0 is the calcium powder consumption during non-coke charging, kg / h; AM1 is the calcium powder consumption during coke charging, kg / h; Dr is the SO2 removal rate; Ca% is the effective content of Ca(OH)2 in the calcium powder; Eff is the calcium powder utilization rate; 64 is the molecular weight of SO2; and 74 is the molecular weight of Ca(OH)2.

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