Method for evaluating quality of limestone-gypsum wet flue gas desulfurization slurry

Abstract

The present application relates to the technical field of limestone-gypsum wet flue gas desulfurization, and particularly relates to a method for evaluating the quality of limestone-gypsum wet flue gas desulfurization slurry, comprising the following steps: A) classifying the quality indicators of the desulfurization tower slurry to realize dimension reduction description of the quality indicators of the desulfurization tower slurry; B) according to the classified quality indicators of the desulfurization tower slurry, establishing a calculation model of each performance characterization parameter of the ideal desulfurization slurry as a target value for evaluating the quality of the desulfurization tower slurry; C) actually measuring each characterization parameter of the quality of the desulfurization tower slurry to obtain a relative deviation from the target value; D) setting a slurry quality grade range of the relative deviation according to engineering needs to evaluate the quality of the limestone-gypsum wet flue gas desulfurization slurry. The present application realizes quantitative description of the quality of the slurry, is used for analyzing the change trend of the quality of the slurry, and greatly improves the safety, reliability and economic level of the desulfurization system.

Description

Technical Field

[0001] This invention relates to the field of limestone-gypsum wet flue gas desulfurization technology, and in particular to a method for evaluating the quality of limestone-gypsum wet flue gas desulfurization slurry. Background Technology

[0002] Limestone-gypsum wet desulfurization technology is widely used in the field of flue gas desulfurization. The SO2 absorption system is the core of the limestone-gypsum wet flue gas desulfurization process, and the quality of the desulfurization tower slurry directly determines the operating level of the SO2 absorption system.

[0003] The desulfurization tower slurry provides a site for limestone dissolution and reaction, and supports the heat and mass transfer processes of the chemical reaction between SO2 and limestone. Furthermore, it ensures the formation of gypsum crystals. It is evident that the desulfurization tower slurry plays a crucial role in all stages of the entire desulfurization system. In actual production, the quality of the desulfurization tower slurry not only affects the economic efficiency of the desulfurization system but also its safety and reliability.

[0004] The failure of desulfurization slurry quality manifests as one or more of the following combined phenomena: a large amount of foam in the slurry, accumulation of suspended matter on the slurry surface, scaling on the desulfurization tower wall, scaling on the spray nozzles, and clogging of the circulating pump filter. Essentially, it is caused by some external factor that prevents the SO2 absorption reaction process from proceeding normally or that impurities brought into the desulfurization system cannot be discharged normally, leading to accumulation and thus changes in the quality of the desulfurization slurry.

[0005] With the gradual implementation of ultra-low emission and comprehensive water resource utilization upgrades for flue gas, the process water quality of some desulfurization systems has undergone significant changes. For example, concentrated wastewater from chemical systems and circulating water discharge are now used as desulfurization process water; other system water sources are being discharged into the desulfurization system, such as wet electrostatic precipitator flushing water being discharged into the desulfurization tower. Furthermore, the increased proportion of fine particulate matter in flue gas, changes in flue gas composition due to wastewater concentration and evaporation, and changes in limestone quality procurement structures have led to a gradual increase in desulfurization slurry quality failures. Therefore, there is an urgent need to develop a slurry quality evaluation method to assess changes in slurry quality in order to improve the safety, reliability, and economy of desulfurization systems. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a method for evaluating the quality of limestone-gypsum wet flue gas desulfurization slurry.

[0007] This invention provides a method for evaluating the quality of limestone-gypsum wet flue gas desulfurization slurry, comprising the following steps:

[0008] A) Classify the quality indicators of the desulfurization tower slurry to achieve a dimensionality-reduced description of the quality indicators of the desulfurization tower slurry;

[0009] B) Based on the classified desulfurization tower slurry quality indicators, establish a calculation model for each performance characterization parameter of the ideal desulfurization slurry, which serves as the target value for evaluating the quality of the desulfurization tower slurry.

[0010] C) Measure the various characterization parameters of the desulfurization tower slurry quality and obtain the relative deviation from the target value;

[0011] D) Set the slurry quality grade within the relative deviation range according to the project requirements, and evaluate the quality of limestone-gypsum wet flue gas desulfurization slurry.

[0012] Preferably, in step A), the quality indicators of the classified desulfurization slurry include the comprehensive performance of the desulfurization slurry, the solid phase performance of the desulfurization slurry, and the liquid phase performance of the desulfurization slurry.

[0013] Preferably, the comprehensive performance characterization parameters of the desulfurization slurry include slurry density ρ, slurry solid content ξ, and slurry pH value.

[0014] Preferably, the relative deviation is calculated according to the following formula:

[0015]

[0016] in, The actual measured results of the comprehensive performance characterization parameters of the desulfurization slurry at time i; A j,min A j,max Recommended values ​​are set for the comprehensive performance characterization parameters of ideal desulfurization slurry; the unit of ρ is kg / m³. 3 The unit of ξ is %.

[0017] Preferably, the performance characterization parameters of the desulfurization slurry solid phase system include the concentrations of CaSO4·2H2O, CaSO3·1 / 2H2O, CaCO3, and MgCO3 in the slurry.

[0018] Preferably, the performance characterization parameters of the ideal desulfurization slurry solid phase system are calculated according to the following formula:

[0019]

[0020] Where, ω j The content of gypsum component j, a byproduct of the dried basis, is expressed as a percentage (%). j Let j be the concentration of solid component j in the slurry, in mol / m³. 3 M j α is the molar mass of solid component j in the slurry, kg / kmol; α is the hydrocyclone underflow recovery rate, %; and ρ is the slurry density, kg / m³. 3 ξ represents the solid content of the slurry, in percentages.

[0021] Preferably, the recommended parameter range for the calculation model of the ideal desulfurization slurry solid phase system performance characterization parameters is as follows:

[0022] α ≥ 70%.

[0023] Preferably, the performance characterization parameters of the desulfurization slurry liquid phase system include the Ca content in the slurry liquid phase system. 2+ concentration of Mg 2+ concentration of Na + concentration, K + concentration of SO4 2- concentration of SO3 2- concentration of HSO3 - concentration and Cl - The concentration.

[0024] Preferably, the performance characterization parameters of the ideal desulfurization slurry liquid phase system are calculated according to the following formula:

[0025]

[0026] in, Mg in the liquid phase of desulfurization slurry 2+ Concentration, Na + Concentration, K + Concentration, Cl - Concentration, mol / m 3 ; Mg in process water 2+ Concentration, Na + Concentration, K + Concentration, mg / L; ρ w ρ l These are the density of process water and the density of the discharged water solution, respectively, in kg / m³. 3 M w M ls These represent process water consumption and limestone consumption, respectively, in kg / h; V l,o The flow rate of the discharged aqueous solution is m. 3 / h; The mass fraction of MgCO3 in limestone, %. The utilization rate of MgCO3 in limestone, in %; Set the chloride ion concentration (ppm) for the discharged aqueous solution;

[0027]

[0028] in, The Ca in the liquid phase system of desulfurization slurry are respectively 2+ Concentration, SO4 2- Concentration, SO3 2-Concentration, HSO3 - Concentration, H + Concentration, mol / m 3 ; The solubility product constants of gypsum and calcium sulfite in the desulfurization slurry are respectively, in mol. 2 / m 6 ; These represent the supersaturation degrees of gypsum and calcium sulfite, respectively; KS2 is the second-order ionization equilibrium constant of sulfurous acid, mol / m 3 pH refers to the acidity or alkalinity of the slurry.

[0029] Preferably, the relative deviation is calculated according to the following formula:

[0030]

[0031] in, The values ​​represent the actual measured results of the solid and liquid phase components of the desulfurization slurry at time i, in mol / m 3 C j The calculated values ​​of solid and liquid phase components for an ideal desulfurization slurry are given in mol / m³. 3 ; The relative deviation of the liquid phase component concentration of the desulfurization slurry at time i is %.

[0032] This invention provides a method for evaluating the quality of limestone-gypsum wet flue gas desulfurization slurry, comprising the following steps: A) classifying the quality indicators of the desulfurization slurry tower to achieve a dimensionality-reduced description of the slurry quality indicators; B) establishing a calculation model for each performance characterization parameter of the ideal desulfurization slurry based on the classified slurry quality indicators, serving as the target value for evaluating the slurry quality; C) actually measuring each characterization parameter of the desulfurization slurry quality and obtaining the relative deviation from the target value; D) setting the slurry quality grade within the relative deviation range according to engineering needs, and evaluating the quality of the limestone-gypsum wet flue gas desulfurization slurry. This invention addresses the multi-factor coupled desulfurization tower slurry, achieving a dimensionality-reduced description of the complex desulfurization tower slurry system, proposing quantitative indicators characterizing the desulfurization slurry quality, establishing a calculation model for the slurry quality of an ideal desulfurization system, and providing a slurry quality evaluation method, which can provide decision-making reference for actual production operators and managers. This invention achieves a quantitative description of slurry quality, used to analyze slurry quality change trends, significantly improving the safety, reliability, and economic level of the desulfurization system. Attached Figure Description

[0033] Figure 1 A schematic diagram of a desulfurization slurry quality evaluation method provided in one embodiment of the present invention;

[0034] Figure 2A diagram illustrating a method for calculating performance characterization parameters of desulfurization slurry liquid phase system according to an embodiment of the present invention. Detailed Implementation

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] This invention provides a method for evaluating the quality of limestone-gypsum wet flue gas desulfurization slurry, comprising the following steps:

[0037] A) Classify the quality indicators of the desulfurization tower slurry to achieve a dimensionality-reduced description of the quality indicators of the desulfurization tower slurry;

[0038] B) Based on the classified desulfurization tower slurry quality indicators, establish a calculation model for each performance characterization parameter of the ideal desulfurization slurry, which serves as the target value for evaluating the quality of the desulfurization tower slurry.

[0039] C) Measure the various characterization parameters of the desulfurization tower slurry quality and obtain the relative deviation from the target value;

[0040] D) Set the slurry quality grade within the relative deviation range according to the project requirements, and evaluate the quality of limestone-gypsum wet flue gas desulfurization slurry.

[0041] Figure 1 A schematic diagram of a desulfurization slurry quality evaluation method provided in an embodiment of the present invention.

[0042] In step A):

[0043] The quality indicators of desulfurization tower slurry are classified to achieve a dimensionality-reduced description of the quality indicators of desulfurization tower slurry.

[0044] This invention first analyzes the key factors affecting the quality of desulfurization tower slurry, and then classifies the quality indicators of desulfurization tower slurry to achieve a dimensionality-reduced description of the quality indicators of desulfurization tower slurry.

[0045] In some embodiments of the present invention, the quality indicators of the classified desulfurization slurry include the comprehensive performance of the desulfurization slurry, the solid phase performance of the desulfurization slurry, and the liquid phase performance of the desulfurization slurry.

[0046] In some embodiments of the present invention, the comprehensive performance characterization parameters of the desulfurization slurry include slurry density ρ, slurry solid content ξ, and slurry pH value.

[0047] In some embodiments of the present invention, the performance characterization parameters of the desulfurization tower slurry solid phase system include the concentrations of CaSO4·2H2O, CaSO3·1 / 2H2O, CaCO3, and MgCO3 in the slurry.

[0048] In some embodiments of the present invention, the performance characterization parameters of the desulfurization slurry liquid phase system include Ca in the slurry. 2+ concentration of Mg 2+ concentration of Na + concentration, K + concentration of SO4 2- concentration of SO3 2- concentration of HSO3 - concentration and Cl - The concentration.

[0049] In step B):

[0050] Based on the classified desulfurization slurry quality indicators, a calculation model for each performance characterization parameter of the ideal desulfurization slurry is established, which serves as the target value for evaluating the quality of the desulfurization tower slurry.

[0051] This invention establishes relevant characterization parameters for the quality of desulfurization tower slurry. Based on the reaction mechanism of the desulfurization system, it establishes a calculation model for the characterization parameters of various properties of ideal desulfurization tower slurry, which serves as the target value for evaluating the quality of desulfurization tower slurry.

[0052] In some embodiments of the present invention, the characterization parameters of the ideal desulfurization system include the characterization parameters of the solid phase components of the ideal desulfurization slurry and the characterization parameters of the liquid phase components of the ideal desulfurization slurry.

[0053] In some embodiments of the present invention, the performance characterization parameters of the ideal desulfurization slurry solid phase system are calculated according to the following formula:

[0054]

[0055] Where, ω j The content of gypsum component j, a byproduct of the dried basis, is expressed as a percentage (%). j Let j be the concentration of solid component j in the slurry, in mol / m³. 3 M j α is the molar mass of solid component j in the slurry, kg / kmol; α is the hydrocyclone underflow recovery rate, %; and ρ is the slurry density, kg / m³. 3 ξ represents the solid content of the slurry, in percentages.

[0056] In some embodiments of the present invention, the recommended parameter range for the calculation model of the ideal desulfurization slurry solid phase system performance characterization parameters is as follows: α ≥ 70%.

[0057] In some embodiments of the present invention, the performance characterization parameters of the ideal desulfurization slurry liquid phase system are calculated according to the following formula:

[0058]

[0059] in, Mg in the liquid phase of desulfurization slurry 2+ Concentration, Na + Concentration, K + Concentration, Cl - Concentration, mol / m 3 ; The Mg content in process water (process water refers to fresh water supplied by other systems, such as water treated from rivers, used by the desulfurization system) is respectively... 2+ Concentration, Na + Concentration, K + Concentration, mg / L; ρ w ρ l These are the density of process water and the density of the discharged water solution, respectively, in kg / m³. 3 M w M ls These represent process water consumption and limestone consumption, respectively, in kg / h; V l,o The flow rate of the discharged aqueous solution is m. 3 / h; The mass fraction of MgCO3 in limestone, %. The utilization rate of MgCO3 in limestone, in %; Set the chloride ion concentration (ppm) for the discharged aqueous solution;

[0060]

[0061] in, The Ca in the liquid phase system of desulfurization slurry are respectively 2+ Concentration, SO4 2- Concentration, SO3 2- Concentration, HSO3 - Concentration, H + Concentration, mol / m 3 ; The solubility product constants of gypsum and calcium sulfite in the desulfurization slurry are respectively, in mol. 2 / m 6 ; These represent the supersaturation degrees of gypsum and calcium sulfite, respectively; KS2 is the second-order ionization equilibrium constant of sulfurous acid, mol / m 3 pH refers to the acidity or alkalinity of the slurry.

[0062] Based on the above relationship, the liquid phase system of the slurry can be obtained. Values ​​for each indicator.

[0063] In some embodiments of the present invention, step B) includes:

[0064] Input the performance characterization parameters of the ideal desulfurization slurry into the computer, and combine the calculation models of the solid phase performance characterization parameters and the liquid phase performance characterization parameters of the desulfurization slurry to calculate the target value of the ideal desulfurization slurry quality.

[0065] In this invention, the slurry liquid phase system characterization parameter calculation program involves setting input parameters based on the performance characterization parameters of an ideal desulfurization slurry liquid phase system, and combining this with a calculation model to obtain the slurry liquid phase system's... Based on the chemical reaction control parameters of the ideal desulfurization system, and combined with the calculation model and existing data... Obtaining the liquid phase system of slurry Values ​​for each indicator.

[0066] Figure 2 A diagram illustrating a method for calculating performance characterization parameters of desulfurization slurry liquid phase system according to an embodiment of the present invention.

[0067] In step C):

[0068] The various characterization parameters of the desulfurization tower slurry quality were actually measured, and the relative deviations from the target values ​​were obtained.

[0069] In some embodiments of the present invention, the relative deviation is calculated according to the following formula:

[0070]

[0071] in, The actual measured results of the comprehensive performance characterization parameters of the desulfurization slurry at time i; A j,min A j,max Recommended values ​​are set for the comprehensive performance characterization parameters of ideal desulfurization slurry; the unit of ρ is kg / m³. 3 The unit of ξ is %.

[0072] In some embodiments of the present invention, the relative deviation is calculated according to the following formula:

[0073]

[0074] in, To obtain the actual results of the solid and liquid phase components of the desulfurization slurry at time i, mol / m 3 C j The calculated values ​​of solid and liquid phase components for an ideal desulfurization slurry are given in mol / m³. 3 ; The relative deviation of the liquid phase component concentration of the desulfurization slurry at time i is %.

[0075] In step D):

[0076] The quality grade of the slurry is set according to the relative deviation range according to the project requirements, and the quality of the limestone-gypsum wet flue gas desulfurization slurry is evaluated.

[0077] The beneficial effects of this invention are:

[0078] This invention addresses the multi-factor coupled desulfurization tower slurry, achieving a dimensionality-reduced description of the complex desulfurization tower slurry system. It proposes quantitative indicators to characterize the quality of the desulfurization slurry, establishes a calculation model for the slurry quality of an ideal desulfurization system, and provides a method for evaluating slurry quality. This invention can provide decision-making references for actual production operators and managers.

[0079] In addition to evaluating the quality of desulfurization tower slurry, slurry quality characterization parameters can be incorporated into the monitoring system. They can also be used to analyze the trend of slurry quality changes, assess the impact of changes in absorbent source, water quality fluctuations, and flue gas composition on the quality of desulfurization tower slurry, and establish a desulfurization tower slurry quality database for correcting desulfurization big data analysis and other work.

[0080] To further illustrate the present invention, the following detailed description of the method for evaluating the quality of limestone-gypsum wet flue gas desulfurization slurry provided by the present invention is provided in conjunction with embodiments, but it should not be construed as a limitation on the scope of protection of the present invention.

[0081] Example

[0082] Reference Figure 1 First, the key factors affecting the quality of desulfurization tower slurry are analyzed. Based on this, the quality indicators of desulfurization tower slurry are classified to achieve a dimensionality-reduced description of the quality indicators. Second, relevant characterization parameters of desulfurization slurry quality are formulated. Based on the reaction mechanism of the desulfurization system, a calculation model for each performance characterization parameter of ideal desulfurization slurry is established as the target value for evaluating the quality of desulfurization tower slurry. Finally, each characterization parameter of desulfurization tower slurry quality is actually measured, and the relative deviation of each characterization parameter from the target value is calculated. According to the engineering needs, the slurry quality grade within the range of relative deviation is set to evaluate the quality of limestone-gypsum wet flue gas desulfurization slurry.

[0083] Reference Figure 2 Calculate the performance characterization parameters of the desulfurization slurry liquid phase system;

[0084] Taking a single-tower desulfurization system as an example, the specific calculation results are shown in Table 1; Table 1 is the evaluation of the comprehensive performance characteristics of the desulfurization slurry at time t; Table 2 is the evaluation of the performance characteristics of the solid phase system of the desulfurization slurry at time t; Table 3 is the evaluation of the performance characteristics of the liquid phase system of the desulfurization slurry at time t.

[0085] Table 1 Evaluation of comprehensive performance characteristics of desulfurization slurry at time t

[0086]

[0087] Table 2 Evaluation of the solid phase performance parameters of the desulfurization slurry at time t

[0088]

[0089]

[0090] Table 3 Evaluation of the performance characteristics of the desulfurization slurry liquid phase system at time t

[0091]

[0092]

[0093]

[0094] The method for evaluating the quality of limestone-gypsum wet flue gas desulfurization slurry provided by this invention is not limited to the determination of "qualified" and "unqualified", but can also be divided into multiple levels according to actual engineering needs.

[0095] The descriptions of the above embodiments are merely illustrative of the methods and core ideas of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for evaluating the quality of limestone-gypsum wet flue gas desulfurization slurry, comprising the following steps: A) Classify the quality indicators of the desulfurization tower slurry to achieve a dimensionality-reduced description of the quality indicators of the desulfurization tower slurry; the classified desulfurization slurry quality indicators include the comprehensive performance of the desulfurization slurry, the solid phase performance of the desulfurization slurry, and the liquid phase performance of the desulfurization slurry. B) Based on the classified desulfurization tower slurry quality indicators, establish a calculation model for each performance characterization parameter of the ideal desulfurization slurry, which serves as the target value for evaluating the quality of the desulfurization tower slurry. The performance characteristics of the ideal desulfurization slurry liquid phase system are calculated according to the following formula: in, Mg in the liquid phase of desulfurization slurry 2+ Concentration, Na + Concentration, K + Concentration, Cl - Concentration, mol / m 3 ; Mg in process water 2+ Concentration, Na + Concentration, K + Concentration, mg / L; ρ w ρ l These are the density of process water and the density of the discharged water solution, respectively, in kg / m³. 3 M w M ls These represent process water consumption and limestone consumption, respectively, in kg / h; V l,o The flow rate of the discharged aqueous solution is m. 3 / h; The mass fraction of MgCO3 in limestone, %. The utilization rate of MgCO3 in limestone, in %; Set the chloride ion concentration (ppm) for the discharged aqueous solution; in, The Ca in the liquid phase system of desulfurization slurry are respectively 2+ Concentration, SO4 2- Concentration, SO3 2- Concentration, HSO3 - Concentration, H + Concentration, mol / m 3 ; The solubility product constants of gypsum and calcium sulfite in the desulfurization slurry are respectively, in mol. 2 / m 6 ; These represent the supersaturation degrees of gypsum and calcium sulfite, respectively; KS2 is the second-order ionization equilibrium constant of sulfurous acid, mol / m 3 pH refers to the acidity or alkalinity of the slurry. C) Measure the various characterization parameters of the desulfurization tower slurry quality and obtain the relative deviation from the target value; The relative deviation is calculated according to the following formula: in, The values ​​represent the actual measured results of the solid and liquid phase components of the desulfurization slurry at time i, in mol / m 3 C j The calculated values ​​of solid and liquid phase components for an ideal desulfurization slurry are given in mol / m³. 3 ; The relative deviation of the liquid phase component concentration of the desulfurization slurry at time i, in %; D) Set the slurry quality grade within the relative deviation range according to the project requirements, and evaluate the quality of limestone-gypsum wet flue gas desulfurization slurry.

2. The evaluation method according to claim 1, characterized in that, The comprehensive performance characterization parameters of the desulfurization slurry include slurry density ρ, slurry solid content ξ, and slurry pH value.

3. The evaluation method according to claim 2, characterized in that, The relative deviation is calculated according to the following formula: in, The actual measured results of the comprehensive performance characterization parameters of the desulfurization slurry at time i; A j,min A j,max Recommended values ​​are set for the comprehensive performance characterization parameters of ideal desulfurization slurry; the unit of ρ is kg / m³. 3 The unit of ξ is %.

4. The evaluation method according to claim 1, characterized in that, The performance characterization parameters of the desulfurization slurry solid phase system include the concentrations of CaSO4·2H2O, CaSO3·1 / 2H2O, CaCO3, and MgCO3 in the slurry.

5. The evaluation method according to claim 4, characterized in that, The performance characterization parameters of the ideal desulfurization slurry solid phase system are calculated according to the following formula: Where, ω j The content of gypsum component j, a byproduct of the dried basis, is expressed as a percentage (%). j Let j be the concentration of solid component j in the slurry, in mol / m³. 3 M j α is the molar mass of solid component j in the slurry, kg / kmol; α is the hydrocyclone underflow recovery rate, %; and ρ is the slurry density, kg / m³. 3 ξ represents the solid content of the slurry, in percentages.

6. The evaluation method according to claim 5, characterized in that, The recommended parameter range for the calculation model of the ideal desulfurization slurry solid phase system performance characterization parameters is as follows: α≥70％。 7. The evaluation method according to claim 1, characterized in that, The performance characterization parameters of the desulfurization slurry liquid phase system include the Ca content in the slurry liquid phase system. 2+ concentration of Mg 2+ concentration of Na + concentration, K + concentration of SO4 2- concentration of SO3 2- concentration of HSO3 - concentration and Cl - The concentration.

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