Method for measuring and calculating solid particulate matter emission reduction of multi-pipe dust removal system for chain grate

Abstract

The invention relates to the technical field of ironmaking pellets, in particular to a method for measuring and calculating the solid particle emission reduction of a multi-pipe dust removal system for a chain grate, which comprises the following steps of: continuously measuring the air temperature and the air speed of direct-flow section pipelines behind a preheating II section of a chain loopback pellet roasting system and in front of a multi-pipe dust remover and behind the multi-pipe dust remover and in front of a regenerative fan; the temperature and wind speed fluctuation curves of the hot air before and after flowing through the multi-pipe dust remover along with time are obtained, so that the pipeline wind temperature and the pipeline working condition wind volume are quantified, the pipeline wind particulate matter concentration is measured through a gravimetric method, and the solid particulate matter emission reduction amount and the overflow wind discharge particulate matter mass range of the multi-pipe dust removal system for the chain grate are calculated; according to parameters such as the pipeline air temperature, the pipeline working condition air volume and the pipeline air particulate matter concentration, the unit time solid particulate matter emission reduction amount and the unit time overflow air exhaust particulate matter mass range of the multi-pipe dust removal system under different working conditions are measured and calculated, and therefore the dust removal effect judgment precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ironmaking pellets, and in particular to a method for calculating the emission reduction of solid particles in a multi-tube dust removal system for a chain grate. Background Art

[0002] Chinese patent publication number CN202022958019.0 discloses a three-electric-field pelletizing dust collector, comprising an electrostatic precipitator housing, an electrostatic generating chamber, a filter bag chamber, a support frame, an upper guardrail, a lower guardrail, a maintenance manhole, a high-voltage rectifier transformer, a flue gas inlet pipe, a purified gas exhaust pipe, a ladder frame, an ash hopper, and an ash storage box. The electrostatic generating chamber and the filter bag chamber are integrated into the left and right sides of the electrostatic precipitator housing, respectively. The support frame is bolted to the lower part of the electrostatic precipitator housing. This utility model removes particulate dust from flue gas emitted during pelletizing or sintering, significantly reducing the amount of dust discharged into the atmosphere. It is an important environmental protection device for improving environmental pollution and air quality. The first anode plate, the second anode plate, the third anode plate, the first cathode plate, the second cathode plate, and the third cathode plate form a three-electric-field arrangement, which improves dust removal and operating efficiency.

[0003] Chinese patent publication number ZL201710796486.8 discloses an industrial air purification system. Aiming at the main physical and chemical characteristics and particle size distribution of unorganized smoke emissions generated in industrial production processes, the invention adopts a three-stage particle capture method of louvers + high-efficiency separation troughs + electrostatic integration, and proposes a two-stage particle cleaning process of spraying + liquid film flushing, ultimately achieving efficient capture of unorganized smoke in industrial production processes and thoroughly improving the working environment. On the basis of "louvers + high-efficiency separation troughs + electrostatic integration three-stage particle capture" and "spraying + liquid film flushing two-stage particle cleaning", it further adopts "filtration concentration + filter press particle raw material recovery" to realize the resource utilization of dust particles and industrial water recycling.

[0004] However, the exhaust gas purification systems and purification effect evaluations involved in the above-mentioned patents all use the exhaust gas particulate matter concentration value after dust removal as a reference basis, and do not calculate the dust collection mass per unit time of the dust collector. Since this value can be used as an important indicator for the particle purification ability of each dust collector, most people in the industry use the product method of the difference in particle concentration before and after purification and the flue gas flow rate for calculation. Due to the limitations of the process equipment conditions of the dust removal system, when the flue gas air volume before purification is greater than the exhaust gas emissions after purification, hot air will overflow from the dust collector and its related pipelines to varying degrees, and the entrained solid particles will be directly discharged into the atmosphere. This part of the unmonitored exhaust pollutant emissions will reduce the accuracy of the conventional calculation method for the solid particulate emission reduction of the multi-tube dust removal system for the chain grate. Summary of the Invention

[0005] The present invention provides a method for calculating the emission reduction of solid particulate matter in a multi-tube dust removal system for a chain grate. By using parameters such as duct air temperature, duct operating air volume, and duct air particulate matter concentration, the method calculates the emission reduction of solid particulate matter per unit time and the mass range of particulate matter discharged per unit time by overflow wind of the multi-tube dust removal system under different operating conditions, thereby improving the accuracy of judging the dust removal effect.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for calculating the reduction in solid particulate matter emissions from a multi-tube dust removal system for a chain grate comprises the following steps:

[0008] S1. Duct air temperature measurement: Use thermocouples to continuously measure the duct air temperature in the direct-flow section from the preheating II stage to the front of the multi-tube dust collector, and from the back of the multi-tube dust collector to the front of the regenerative heat fan in the chain return ball pellet roasting system. Obtain the hot air temperature fluctuation curves F(t) and f(t) before and after the multi-tube dust collector over time. Then calculate the flue gas temperature T0 before and after purification by the multi-tube dust collector.

[0009] S2. Duct working air volume measurement: Continuously measure the wind speed at the same location as the duct air temperature measurement to obtain the hot air velocity fluctuation curves V0(t) and V(t) before and after passing through the multi-tube dust collector. Then calculate the flue gas working flow rate Q0 before and after purification through the multi-tube dust collector and the flue gas working flow rate Q after purification.

[0010] S3. Duct air particle concentration measurement: The duct air particle concentration measurement point is the same as the duct air temperature and duct operating air volume measurement location. A fixed volume of gas is extracted at a constant rate so that the particles are trapped on a filter membrane of known mass. After drying, the particle concentrations q0 and q (mg·Nm) before and after passing through the multi-tube dust collector are obtained based on the weight difference of the filter membrane before and after sampling and the ratio of the sampling volume. -3 ;

[0011] S4. Quantitative calculation: Based on the above-measured duct air temperature, duct operating air volume and duct air particulate matter concentration data, calculate the solid particulate matter emission reduction of the multi-tube dust removal system for the chain grate machine and the mass range of the particulate matter discharged by the overflow air.

[0012] Furthermore, the flue gas temperature T0 before and after purification by multi-tube dust removal is calculated as follows:

[0013]

[0014]

[0015] Where t is the test synchronization time, t0 is the test start time, and t1 is the test completion time. The units of T0 and T are both K.

[0016] Furthermore, the calculation method of the flue gas working flow rate Q0 before and after purification by the multi-tube dust removal is as follows:

[0017]

[0018] Among them, S0 is the cross-sectional area of the test position before the multi-tube dust removal purification, unit is m 2 ; S is the cross-sectional area of the test position after multi-tube dust removal and purification, unit: m 2 ; Q0, Q unit m 3 ·h -1 .

[0019] Furthermore, the method for calculating the solid particulate matter emission reduction of the multi-tube dust removal system for the chain grate in step S4 is as follows:

[0020]

[0021] Where M is the solid particulate matter emission reduction per unit time, kg·h -1 ;

[0022] q0 is the concentration of particulate matter before pipeline gas purification, mg·Nm -3 ;

[0023] q is the concentration of particulate matter after pipeline gas purification, mg·Nm -3 ;

[0024] η is the correction factor, dimensionless;

[0025] Q0 is the flue gas flow rate before purification, m 3 ·h -1 ;

[0026] Q is the working flow rate of flue gas after purification, m 3 ·h -1 ;

[0027] T0 is the flue gas temperature before purification, K;

[0028] T is the flue gas temperature after purification, K.

[0029] Furthermore, the q0∈[10mg·Nm -3 , 200mg·Nm -3 ], q∈[0mg·Nm -3 , 10mg·Nm -3 )、η∈(0,1)、Q0∈[50000m 3 ·h -1 ,∞)、Q∈[20000m 3 ·h -1, ∞), T0∈[493.15K, 923.15K], T∈[473.15K, 903.15K].

[0030] Furthermore, the method for calculating the mass range of particulate matter discharged by the overflow wind in step S4 is as follows:

[0031]

[0032]

[0033] Among them, m min is the lower limit of the mass of particulate matter discharged by overflow wind per unit time, kg·h -1 ;

[0034] m max is the upper limit of the mass of particulate matter discharged by overflow wind per unit time, kg·h -1 .

[0035] Furthermore, the product of the flue gas operating flow rate before purification and the flue gas temperature after purification is greater than or equal to the product of the flue gas operating flow rate after purification and the flue gas temperature before purification.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention introduces concepts such as dust collector and its pipeline overflow and discharge of particulate matter into the calculation of solid particulate emission reduction of multi-tube dust removal system for chain grate machine, weakens the error caused by unmonitored exhaust pollutant emission and improves measurement accuracy; in the prior art, only the solid particulate concentration of exhaust gas after dust removal is used as the basis for evaluating the dust removal effect, which has the disadvantage of being unable to quantify. The method of the present invention synchronously measures parameters such as wind speed, wind temperature and particulate matter content in the front and rear pipelines of the multi-tube dust removal system, and considers the influence of the absolute overflow air volume on the measurement accuracy. The result is more comprehensive, more factors are considered, and the final result is more obvious for investigating the effect of the dust collector. Compared with the conventional method, the error of the solid particulate emission reduction per unit time calculated by the method of the present invention is reduced from 32.23% to 70.22% to below 13.92%, and the average error is reduced by 39.45%. DETAILED DESCRIPTION

[0038] The specific embodiments of the present invention are further described below:

[0039] Those skilled in the art can refer to the content of this article and appropriately improve the process parameters. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments. It is obvious that relevant persons can modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0040] The present invention provides a method for calculating the amount of solid particulate matter emission reduction of a multi-tube dust removal system for a chain grate, comprising the following steps:

[0041] S1. Duct air temperature measurement: Use thermocouples to continuously measure the duct air temperature in the direct-flow section from the preheating II section of the chain return ball pellet roasting system to the front of the multi-tube dust collector, and from the multi-tube dust collector to the front of the regenerative heat fan. Obtain the hot air temperature fluctuation curves F(t) and f(t) before and after the multi-tube dust collector. Then calculate the flue gas temperature T0 before and after purification by the multi-tube dust collector. The calculation method is as follows:

[0042]

[0043]

[0044] Where t is the test synchronization time, t0 is the test start time, and t1 is the test completion time. The units of T0 and T are both K.

[0045] S2. Measurement of duct working air volume: The measurement point of duct working air volume is the same as the measurement position of duct air temperature. The working principle of Pitot tube flow velocity measurement is used to continuously measure the duct wind velocity of the direct current section from the preheating II stage to the front of the multi-tube dust collector and from the back of the multi-tube dust collector to the front of the heat recovery fan in the chain return ball ball roasting system. The hot air velocity fluctuation curves V0(t) and V(t) before and after the multi-tube dust collector are obtained. Then, the working flow rate Q0 of the flue gas before and after purification by the multi-tube dust collector and the working flow rate Q of the flue gas after purification are calculated. The calculation method is as follows:

[0046]

[0047] Among them, S0 is the cross-sectional area of the test position before the multi-tube dust removal purification, unit is m 2 ; S is the cross-sectional area of the test position after multi-tube dust removal and purification, unit: m 2 ; Q0, Q unit m 3 ·h -1 .

[0048] S3. Duct air particulate matter concentration measurement: The duct air particulate matter concentration measurement point is the same as the duct air temperature and duct operating air volume measurement location. The measurement adopts the gravimetric method. A fixed volume of gas is extracted at a constant rate so that the particles are trapped on a filter membrane of known mass. After drying, the particle concentrations q0 and q before and after passing through the multi-tube dust collector are obtained based on the weight difference of the filter membrane before and after sampling and the ratio of the sampling volume. -3 .

[0049] S4. Quantitative calculation: Based on the above-measured duct air temperature, duct operating air volume, and duct air particulate matter concentration data, calculate the solid particulate matter emission reduction of the multi-tube dust removal system for the chain grate machine and the mass range of the particulate matter discharged by the overflow air;

[0050] The calculation method for solid particulate matter emission reduction of multi-tube dust removal system for chain grate is as follows:

[0051]

[0052] Where M is the solid particulate matter emission reduction per unit time, kg·h -1 ;

[0053] q0 is the concentration of particulate matter before pipeline gas purification, mg·Nm -3 ;

[0054] q is the concentration of particulate matter after pipeline gas purification, mg·Nm -3 ;

[0055] η is the correction factor, dimensionless;

[0056] Q0 is the flue gas flow rate before purification, m 3 ·h -1 ;

[0057] Q is the working flow rate of flue gas after purification, m 3 ·h -1 ;

[0058] T0 is the flue gas temperature before purification, K;

[0059] T is the flue gas temperature after purification, K;

[0060] The calculation method for the mass range of particulate matter discharged by overflow wind is as follows:

[0061]

[0062] Among them, m min is the lower limit of the mass of particulate matter discharged by overflow wind per unit time, kg·h -1 ;

[0063] m max is the upper limit of the mass of particulate matter discharged by overflow wind per unit time, kg·h -1 ;

[0064] Formulas (12)-(14) satisfy the following conditions:

[0065] q0∈[10mg·Nm -3 , 200mg·Nm -3 ], q∈[0mg·Nm -3 , 10mg·Nm -3)、η∈(0,1)、Q0∈[50000m 3 ·h -1 ,∞)、Q∈[20000m 3 ·h -1 , ∞), T0∈[493.15K, 923.15K], T∈[473.15K, 903.15K], Q0×T≥Q×T0.

[0066] The following examples are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0067] [Example]

[0068] A method for calculating the solid particulate matter emission reduction of a multi-tube dust removal system for a chain grate is presented. Field tests of parameters such as duct air temperature, duct operating air volume, and duct air particulate matter concentration under different operating conditions of multiple chain grate multi-tube dust removal systems are conducted, and the results of the selection of correction coefficients are shown in Table 1:

[0069] Table 1 Test data

[0070]

[0071] The solid particulate matter emission reduction per unit time M and the mass range of particulate matter discharged by overflow wind per unit time m are calculated by formulas (12)-(14). min and m max As shown in Table 2:

[0072] Table 2 Calculation results

[0073]

[0074] In the embodiment, the solid particulate matter emission reduction per unit time calculated by the method of the present invention is compared with the conventional method. The error is reduced from 32.23% to 70.22% to below 13.92%, and the average error is reduced by 39.45%. The accuracy of the solid particulate matter emission reduction evaluation of the multi-tube dust removal system for the chain grate machine is greatly improved. At the same time, the concept of exhausting particulate matter by overflow air is proposed for the first time. The average emission in the above embodiment is 0.2043 to 0.5806 kg·h -1 This has brought attention to this part of exhaust particulate matter emissions that has not yet been monitored.

[0075] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for calculating the reduction of solid particulate matter emissions from a multi-tube dust removal system for a chain grate, characterized in that: The steps include: S1. Duct air temperature measurement: Use thermocouples to continuously measure the duct air temperature in the direct-flow section from the preheating II stage to the front of the multi-tube dust collector, and from the back of the multi-tube dust collector to the front of the regenerative heat fan in the chain return ball pellet roasting system. Obtain the hot air temperature fluctuation curves F(t) and f(t) before and after the multi-tube dust collector over time. Then calculate the flue gas temperature T0 before and after purification by the multi-tube dust collector. S2. Duct working air volume measurement: Continuously measure the wind speed at the same location as the duct air temperature measurement to obtain the hot air velocity fluctuation curves V0(t) and V(t) before and after passing through the multi-tube dust collector. Then calculate the flue gas working flow rate Q0 before and after purification through the multi-tube dust collector and the flue gas working flow rate Q after purification. S3. Duct air particle concentration measurement: The duct air particle concentration measurement point is the same as the duct air temperature and duct operating air volume measurement location. A fixed volume of gas is extracted at a constant rate so that the particles are trapped on a filter membrane of known mass. After drying, the particle concentrations q0 and q (mg·Nm) before and after passing through the multi-tube dust collector are obtained based on the weight difference of the filter membrane before and after sampling and the ratio of the sampling volume. -3 ; S4. Quantitative calculation: Based on the above-measured duct air temperature, duct operating air volume and duct air particulate matter concentration data, calculate the solid particulate matter emission reduction of the multi-tube dust removal system for the chain grate machine and the mass range of the particulate matter discharged by the overflow air.

2. The method for calculating the reduction in solid particulate matter emissions from a multi-tube dust removal system for a chain grate according to claim 1, characterized in that: The calculation method of the flue gas temperature T0 before and after purification by multi-tube dust removal is as follows: Where t is the test synchronization time, t0 is the test start time, and t1 is the test completion time. The units of T0 and T are both K.

3. The method for calculating the reduction in solid particulate matter emissions from a multi-tube dust removal system for a chain grate according to claim 1, wherein: The calculation method of the flue gas working flow rate Q0 before and after purification by multi-tube dust removal is as follows: Among them, S0 is the cross-sectional area of the test position before the multi-tube dust removal purification, unit is m 2 ; S is the cross-sectional area of the test position after multi-tube dust removal and purification, unit: m 2 ; Q0, Q unit m 3 ·h -1 .

4. The method for calculating the reduction in solid particulate matter emissions from a multi-tube dust removal system for a chain grate according to claim 1, wherein: The method for calculating the solid particulate matter emission reduction of the multi-tube dust removal system for the chain grate in step S4 is as follows: Where M is the solid particulate matter emission reduction per unit time, kg·h -1 ; q0 is the concentration of particulate matter before pipeline gas purification, mg·Nm -3 ; q is the concentration of particulate matter after pipeline gas purification, mg·Nm -3 ; η is the correction factor, dimensionless; Q0 is the flue gas flow rate before purification, m 3 ·h -1 ; Q is the working flow rate of flue gas after purification, m 3 ·h -1 ; T0 is the flue gas temperature before purification, K; T is the flue gas temperature after purification, K.

5. The method for calculating the reduction in solid particulate matter emissions from a multi-tube dust removal system for a chain grate according to claim 4, wherein: The q0∈[10mg·Nm -3 , 200mg·Nm -3 ], q∈[0mg·Nm -3 , 10mg·Nm -3 )、η∈(0,1)、Q0∈[50000m 3 ·h -1 ,∞)、Q∈[20000m 3 ·h -1 , ∞), T0∈[493.15K, 923.15K], T∈[473.15K, 903.15K].

6. The method for calculating the reduction in solid particulate matter emissions from a multi-tube dust removal system for a chain grate according to claim 5, characterized in that: The method for calculating the mass range of particulate matter discharged by the overflow wind in step S4 is as follows: Among them, m min is the lower limit of the mass of particulate matter discharged by overflow wind per unit time, kg·h -1 ; m max The upper limit of the mass of particulate matter discharged by overflow wind per unit time, kg·h -1 .

7. The method for calculating the reduction in solid particulate matter emissions from a multi-tube dust removal system for a chain grate according to claim 6, characterized in that: The product of the working flow rate of the flue gas before purification and the temperature of the flue gas after purification is greater than or equal to the product of the working flow rate of the flue gas after purification and the temperature of the flue gas before purification.

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