| CPC G06Q 10/0633 (2013.01) [B01D 53/60 (2013.01); B01D 53/64 (2013.01); B01D 53/75 (2013.01); G06F 30/20 (2020.01); G06Q 10/0631 (2013.01); B01D 2257/302 (2013.01); B01D 2258/0283 (2013.01)] | 5 Claims |
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1. A computer-implemented method for controlling simultaneous removal of multi-pollutant including nitrogen oxide (NOx), sulfur oxide (SO2 and SO3), particulate matter (PM) and mercury (Hg), comprising:
(a) modeling of a multi-device multi-pollutant simultaneous removal process of an emission system by including prediction of a multi-pollutant generation process, modeling of a multi-pollutant simultaneous removal process of a desulfurization system, modeling of a multi-pollutant simultaneous removal and transformation process of a denitration system, and modeling of a multi-pollutant removal process of a precipitation system;
(b) evaluating multi-pollutant emission reduction costs under a plurality of loads, coal qualities, pollutant concentrations and operating parameters through a global operating cost evaluation method of the ultra-low emission system;
(c) realizing minute-level planning and optimization of emission reductions of a global pollutant emission reduction device under different emission targets through a multi-pollutant, multi-target and multi-condition global operating optimization method; and
(d) removing multi-pollutant simultaneously according to a predetermined emission standard of the multi-pollutant;
wherein, in step (a), the prediction of the multi-pollutant generation process is as follows:
establishing a boiler operating database and a multi-pollutant outlet concentration database under different conditions and variable coal qualities by acquiring long-term operating data of a boiler and a continuous emission monitoring system and combining coal quality detection data and test reports of the multiple pollutants including NOx, SO2, SO3, PM and Hg; and
establishing a model for describing a corresponding relationship of boiler parameters and coal quality parameters with the concentrations of the multiple pollutants at a boiler outlet under different coal qualities and loads, based on the boiler operating database and the multi-pollutant outlet concentration database through a data modeling method;
wherein, in step (a), modeling of the multi-pollutant simultaneous removal process of the desulfurization system is as follows:
a corresponding relationship of inlet SO2 concentration, inlet flue gas temperature, liquid-gas ratio, slurry density and pH with outlet SO2 concentration of the desulfurization system, a corresponding relationship of inlet SO3 concentration, inlet SO2 concentration, inlet dust content, inlet flue gas temperature, liquid-gas ratio and flue gas velocity with outlet SO3 concentration of the desulfurization system, and a corresponding relationship of inlet Hg concentration, inlet dust content, load, flue gas velocity and inlet flue gas temperature with outlet Hg concentration are established by combining coal qualities, boiler operating parameters, inlet flue gas parameters of the desulfurization system, and operating parameter historical data of the desulfurization system, and then, a model for the multi-pollutant simultaneous removal process of the desulfurization system is obtained;
wherein, in step (a), modeling of the multi-pollutant simultaneous removal and transformation process of the denitration system is as follows:
based on an operating mechanism of a selective catalytic reduction (SCR) denitration system, a corresponding relationship of inlet NOx concentration, flue gas parameters, reaction condition and reducer supply with outlet NOx concentration of the denitration system a corresponding relationship of inlet SO2 concentration, flue gas parameters, reaction condition and reducer supply with SO2-to-SO3 transformation rate in the denitration system, and a corresponding relationship of inlet Hg concentration, flue gas parameters, reaction condition and reducer supply with transformation ratio of particulate mercury, mercury oxides and elementary mercury in the denitration system are established by combining inlet flue gas parameters, online detection results of a pollutant continuous emission monitoring system (CEMS) and operating parameter historical data of the denitration system, and then, a model for describing the multi-pollutant simultaneous removal and transformation process of the denitration system under different conditions and operating parameters is obtained based on these corresponding relationships;
wherein, in step (a), modeling of the multi-pollutant removal process of the precipitation system is as follows:
based on a particulate matter removal mechanism of an electrostatic precipitation system, a corresponding relationship of coal quality, load, flue gas temperature, flue gas rate, operating voltage and outlet particulate matter concentration of a dry electric precipitator, a corresponding relationship of coal quality, load, flue gas temperature, flue gas rate, theoretical SO3 concentration of the denitration system, operating voltage and outlet SO3 concentration of the dry electric precipitator, a corresponding relationship of coal quality, load, flue gas temperature, flue gas rate, theoretical Hg concentration of the denitration system and outlet Hg concentration of the dry electric precipitator, a corresponding relationship of coal quality, load, flue gas temperature, flue gas rate, circulating water quantity, operating voltage and outlet particulate matter concentration of a wet electric precipitator, a corresponding relationship of coal quality, load, flue gas temperature, flue gas rate, inlet NOx concentration, circulating water quantity, circulating water pH, operating voltage and outlet NOx concentration of the wet electric precipitator, a corresponding relationship of coal quality, load, flue gas temperature, flue gas rate, inlet SO2 concentration, circulating water quantity, circulating water pH, operating voltage and outlet SO2 concentration of the wet electric precipitator, a corresponding relationship of coal quality, load, flue gas temperature, flue gas rate, inlet SO3 concentration, circulating water quantity, circulating water pH, operating voltage and outlet SO3 concentration of the wet electric precipitator, and a corresponding relationship of coal quality, load, flue gas temperature, flue gas rate, inlet Hg concentration, circulating water quantity, circulating water pH, operating voltage and outlet Hg concentration of the wet electric precipitator are established by combining coal quality, boiler operating parameters, inlet flue gas parameters of the electrostatic precipitation system, and historical operating data; then, a model for describing the multi-pollutant simultaneous removal process of the precipitation system is obtained;
wherein, in step (a), the prediction of the multi-pollutant generation process refers to prediction of the concentration of the multiple pollutants, including NOx, SO2, SO3, PM and Hg at a boiler outlet according to real-time boiler operating data and periodically-updated coal quality reports;
a boiler model is established through the following steps:
S101: collecting boiler parameters, coal quality parameters and a boiler outlet test report;
S102: collecting long-term operating historical data including boiler coal feed, flue gas, water, and boiler outlet pollutant concentrations detected by the CEMS;
S103: marking out typical boiler load intervals according to the test report and online operating data, and obtaining corresponding datasets of boiler operating parameters, coal qualities and outlet pollutant concentrations in the typical boiler load intervals;
S104: for pollutants, data of which is monitored online by the CEMS, obtaining a corresponding relationship of the boiler operating data and coal quality parameters with outlet pollutant concentrations through a data modeling method, based on the datasets;
S105: for pollutants, data of which is not monitored online by the CEMS, obtaining a corresponding relationship of the boiler operating data and the coal quality parameters with outlet pollutant concentrations through a data modeling method according to coal quality data and the test report, based on the datasets; and
S106: combining the model obtained in S104 and the model obtain in S105 to obtain the multi-pollutant concentration prediction model of the boiler;
wherein, in step (a), the model for describing the multi-pollutant simultaneous removal process of the desulfurization system is obtained specifically through the following steps:
S201: collecting design parameters and test reports of all devices of the desulfurization system;
S202: collecting online operating historical data of the desulfurization system, including boiler load, inlet flue gas parameters, flue gas rate, pH, liquid-gas ratio, slurry density, and inlet concentration and outlet concentrations;
S203: marking out typical load intervals and pollutant concentration intervals according to data distribution, and obtaining corresponding datasets of boiler loads, coal qualities and outlet pollutant concentrations in the typical boiler load intervals and the pollutant concentration intervals;
S204: based on the datasets, establishing an SO2 removal mechanism model in the typical boiler load intervals and in the pollutant concentration intervals according to an SO2 removal mechanism of a desulfurization tower, and correcting the model according to historical data to obtain corresponding relationships of inlet SO2 concentration, inlet flue gas parameters, liquid-gas ratio, slurry density and pH with outlet SO2 concentration in the typical boiler load intervals and the pollutant concentration intervals;
S205: based on the datasets, obtaining corresponding relationships of inlet SO3 concentration, inlet SO2 concentration, inlet dust content, inlet flue gas temperature, liquid-gas ratio and flue gas velocity with outlet SO3 concentration of the desulfurization system and corresponding relationships of inlet Hg concentration, inlet dust content, load, flue gas velocity and inlet flue gas temperature with outlet Hg concentration, in the typical boiler load intervals and the pollutant concentration intervals through a data modeling method according to results of the test reports; and
S206: based on these corresponding relationships, obtaining the model for describing the multi-pollutant simultaneous removal and transformation process of the desulfurization system under different conditions and operating parameters;
wherein, in step (a), the model for describing the multi-pollutant simultaneous removal and transformation process of the denitration system is established specifically through the following steps:
S301: collecting design parameters of a denitration device, catalyst parameters, a catalyst test report, and a reducer test report;
S302: collecting historical data having an influence on online operation of the denitration device, including boiler load, operating temperature, flue gas rate, reducer supply, and inlet and outlet pollutant concentrations detected by the CEMS;
S303: marking out typical load intervals and a pollutant concentration intervals according to data distribution, and obtaining corresponding datasets of boiler load, coal quality and outlet pollutant concentration in the typical boiler load intervals and the pollutant concentration intervals;
S304: based on the datasets, establishing a mechanism model of the denitration device in the typical boiler load intervals and the pollutant concentration intervals according to an NOx removal mechanism of the denitration system, and correcting the model according to the historical data to obtain corresponding relationships of inlet NOx concentration, flue gas parameter, reaction condition and reducer supply with the outlet NOx concentration of the denitration device, in the typical boiler load intervals and the pollutant concentration intervals;
S305: based on the datasets, obtaining corresponding relationships of inlet SO2 concentration, flue gas parameters, reaction condition and reducer supply with the SO2-to-SO3 transformation rate in the denitration device, and corresponding relationships of inlet Hg concentration, flue gas parameters, reaction condition and reducer supply with the transformation rate of particulate mercury, mercury oxides and elementary mercury in the denitration system, in the typical boiler load intervals and the pollutant concentration intervals according to results in the test reports through a data modeling method; and
S306: based on these corresponding relationships, obtaining the model for describing the multi-pollutant simultaneous removal and transformation process of the denitration system under different conditions and operating parameters;
wherein, in step (a), the model for describing the multi-pollutant simultaneous removal process of the precipitation system is established specifically through the following steps:
S401: collecting design parameters and test reports of electrostatic precipitators;
S402: collecting historical data having an influence on online operation of the electrostatic precipitators, including boiler load, operating temperature, flue gas rate, secondary voltage, secondary current, and inlet and outlet pollutant concentrations detected by the CEMS;
S403: marking out typical load intervals and pollutant concentration intervals according to data distribution, and obtaining corresponding datasets of boiler load, coal quality and outlet pollutant concentration in the typical boiler load intervals and the pollutant concentration intervals;
S404: based on the datasets, establishing PM removal mechanism models of the electrostatic precipitators in the typical boiler load intervals and the pollutant concentration intervals according to a PM removal mechanism of the electrostatic precipitators, and correcting the models by means of the historical data to obtain corresponding relationships of inlet PM concentration, flue gas parameter and operating voltage with the outlet PM concentration of the electrostatic precipitators, in the typical boiler intervals and the pollutant concentration intervals;
S405: based on the datasets, obtaining corresponding relationships of inlet SO3 concentration, inlet PM concentration, boiler load, operating temperature, flue gas rate operating voltage and outlet SO3 concentration and corresponding relationships of inlet Hg concentration, inlet PM concentration, boiler load, operating temperature, flue gas rate, operating voltage and outlet Hg concentration in the typical boiler load interval and the pollutant concentration interval through a data modeling method according to results of the test report; and
S406: based on these corresponding relationships, obtaining the model for describing the multi-pollutant simultaneous removal and transformation process of the precipitation system under different conditions and operating parameters;
wherein by means of modeling of the multi-pollutant removal and transformation process of the denitration system, real-time description of a dynamic transformation process of NOx, SO2, SO3 and Hg and prediction of the concentration are realized; during modeling of the multi-pollutant simultaneous removal process of the desulfurization system, inlet flue gas parameters include inlet flue gas temperature, inlet SO2 concentration, inlet SO3 concentration, inlet particulate matter concentration and inlet Hg concentration, and outlet flue gas parameters include outlet flue gas temperature, outlet SO2 concentration, outlet SO3 concentration, outlet particulate matter concentration and outlet Hg concentration; the established mechanism models are corrected by coherent combination;
wherein the global operating cost evaluation method of the ultra-low emission system specifically includes operating costs and fixed costs of all pollutant emission reduction systems;
regarding to a limestone-gypsum wet desulphurization system, a total operating cost and a fixed cost are expressed as:
COSTWFGD=COSTbf+COSTsa+COSTscp+COSToab+COSTCaCO3+COSTWFGD_w−RCaSO4
COSTWFGD_fix=COSTWFGD_d+COSTWFGD_r+COSTWFGD_m
wherein, power consumption of booster fans COSTbf, power consumption of oxidization blowers COSTsa, power consumption of slurry circulating pumps COSTscp, power consumption of slurry agitators COSToab, a limestone slurry cost COSTCaCO3, a process water cost COSTWFGD_w, a by-product gypsum revenue RCaCO4, a depreciation cost COSTWFGD_d, a repair cost COSTWFGD_r, and a manual cost COSTWFGD_m are included;
the operating cost of the desulfurization system includes energy consumption and material consumption, wherein the energy consumption is mainly generated by a motor of the desulfurization system and includes the power consumption of booster fans, the power consumption of oxidization blowers, the power consumption of slurry circulating pumps and the power consumption of the slurry agitators, and the cost are calculated as follows:
 wherein, q is a real-time boiler load, nbf, nsa, nscp and noab respectively represent the number of booster fans in operation, the number of oxidization fans in operation, the number of slurry circulating pumps in operation and the number of slurry agitators in operation, Ui and Ii respectively represent the voltage and current of an ith facility, cos φ is a power factor, and PE is the electricity price;
αWFGD is the ratio of the resistance of a desulfurization tower to the total resistance in a second half and is calculated as follows:
 wherein, pdt is a pressure drop of the desulfurization tower, pWESP is a pressure drop of the wet electrostatic precipitator under resistance, and pgd2 is a pressure drop of a gas duct under resistance;
material consumption of the desulfurization system includes limestone consumption and process water consumption, the limestone consumption is calculated as follows:
 wherein, cSO2_in and cSO2_out respectively represent SO2 concentrations of inlet flue gas and outlet flue gas of the desulfurization system, MCaCO3 and MSO2 respectively represent molecular weights of CaCO3 and SO2, λ represents the purity of limestone, PCaCO3 represents the price of limestone, δ1 represents a calcium-sulfur ratio, and V represents the flue gas rate which is in a positive correlation with the boiler load and is calculated according to the following formula:
V=m×q×Vtc
wherein, Vtc is the amount of flue gas generated by coal per unit, and m is coal quality;
the process water consumption is calculated as follows:
 wherein, MH2O s the molecular weight of water, and is the price of water;
gypsum, as revenue obtained in the operating process of the desulfurization system, is included in cost calculation of the limestone-gypsum wet desulfurization system, and the revenue is calculated as follows:
 wherein, MCaSO4 is the molecular weight of gypsum, and PCaSO4 is the price of gypsum;
the fixed cost of the desulfurization system includes the depreciation cost COSTWFGD_d, the repair cost COSTWFGD_r and the manual cost COSTWFGD_m which are respectively calculated as follows:
 wherein, Q is the capacity of a unit, H is annual operating hours of the unit, PWFGD_init s an initial investment cost of the desulfurization system, ηWFGD is a fixed assets formation rate of the desulfurization system, YWFGD is a depreciable life of the desulfurization system, ηWFGD_r is the proportion of the repair cost of the desulfurization system to an investment cost, ηWFGD is the total number of workers, and SWFGDi is the annual salary of an ith worker of the desulfurization system;
regarding to the SCR denitration system, a total operating cost and a fixed cost are expressed as follows:
COSTSCR=COSTSCR_idf+COSTsb+COSTadf+COSTNH3+COSTC
COSTSCR_fix=COSTSCR_d+COSTSCR_r+COSTSCR_m
the operating cost includes energy consumption and material consumption, and the energy consumption includes power consumption of induced draft fans, power consumption of soot blowers and power consumption of dilution fans, which are respectively calculated as follows:
 wherein, nidf, nsb and nadf are respectively the number of induced draft fans in operation, the number of soot blowers in operation and the number of dilution fans in operation, Psteam is empirical steam consumption, CVs is empirical reference catalyst consumption, and CV is actual catalyst consumption;
αSCR represents the ratio of the resistance of a denitration reactor to the total resistance in a first half and is calculated as follows:
 the material consumption of the denitration system includes a liquid ammonia cost and a catalyst cost, the liquid ammonia cost is calculated as follows:
 wherein, CNOx_in and CNOx_out respectively represent NOx concentrations of inlet flue gas and outlet flue gas of the denitration system, MNH3 and MNO respectively represent molecular weights of NH3 and NO, and PNH3 is the price of liquid ammonia;
the catalyst cost is calculated as follows:
 wherein, Pc is the price of a catalyst, Q is the capacity of a unit, and h is the annual operating hours of the unit;
the fixed cost of the denitration system includes a depreciation cost COSTSCR_d, a repair cost COSTSCR_r and a manual cost COSTSCR_m, which are respectively calculated as follows:
 wherein, PSCR_init is an initial investment cost of the denitration system, ηSCR is a fixed assets formation rate of the denitration system, YSCR is a depreciable life of the denitration system, ηSCR_r is the proportion of the repair cost of the denitration system to the investment cost, nSCR is the total number of workers of the denitration system, SSCRi is the annual salary of an ith worker;
regarding to electrostatic precipitation systems, total operating costs and fixed costs of a dry electrostatic precipitation system and a wet electrostatic precipitation system are respectively expressed as follows:
COSTESP=COSTESP_idf+COSTESP_e
COSTESP_fix=COSTESP_d+COSTESP_r+COSTESP_m
COSTWESP=COSTWESP_idf+COSTWESP_e+COSTWESP_w+COSTNa+COSTwc
COSTWESP_fix=COSTWESP_d+COSTWESP_r+COSTWESP_m
the operating costs include power consumption,
power consumption of a dry electrostatic precipitator includes power consumption of induced draft fans and power consumption of power supplies, which are respectively calculated as follows:
 wherein, ne is the number of electric fields, and αESP is the proportion of the resistance of the dry electrostatic precipitator to the total resistance in the first half and is calculated as follows:
 power consumption of a wet electrostatic precipitator includes power consumption of induced draft fans, power consumption of power supplies, a power cost and a material cost, and the power consumption of induced draft fans of the wet electrostatic precipitator is calculated as follows:
 the power consumption of power supplies of the wet electrostatic precipitator is:
 the power cost is calculated as follows:
 the material cost of the wet electrostatic precipitator includes a process water cost and an alkali consumption cost, which are calculated as follows:
 the fixed costs of the dry electrostatic precipitation system and the wet electrostatic precipitation system include depreciation costs COSTESP_d and COSTWESP_d, repair costs COSTESP_r and COSTWESP_r, and manual costs COSTESP_m and COSTWESP_m, which are respectively calculated as follows:
  wherein, PESP_init and PWESP_init respectively represent initial investment costs of the dry electrostatic precipitation system and the wet electrostatic precipitation system, ηESP and ηWESP respectively represent fixed assets formation rates of the dry electrostatic precipitation system and the wet electrostatic precipitation system, YESP and YWESP respectively represent a depreciable life of the dry electrostatic precipitation system and a depreciable life of the wet electrostatic precipitation system, ηESP_r and ηWESP_r respectively represent the ratio of the repair cost of the dry electrostatic precipitation system to the investment cost and the ratio of the respectively represent the total number of workers of the dry electrostatic precipitation system, and SESPi and SWESPi respectively represent the annual salary of an ith worker of the dry electrostatic precipitation system.
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