An evaluation method combining boiler energy efficiency and economic and technical performance for coupled pollutant emission reduction

Abstract

The present invention discloses an evaluation method for combining boiler energy efficiency and economic and technical characteristics for coupled pollutant emission reduction, and belongs to the field of boiler energy efficiency. The method comprises the following steps: S100, calculating the desulfurization cost and the unit standard energy consumption of desulfurization; S200, calculating the denitrification cost and the unit standard energy consumption of denitrification; S300, calculating the dust removal cost and the unit standard energy consumption of dust removal; S400, calculating the cost of energy saving of waste heat recovery, the energy saving profit and the net unit standard saving of waste heat recovery; S500, adding the desulfurization cost, denitrification cost, dust removal cost, the cost of energy saving of waste heat recovery and the energy saving profit to form the final cost or profit; adding the unit standard energy consumption of desulfurization, denitrification and dust removal and the net unit standard saving of waste heat recovery to form the final unit standard energy consumption or standard saving.

Description

Technical Field

[0001] The invention relates to an evaluation method combining boiler energy efficiency with economic and technical performance for coupled pollutant emission reduction, and belongs to the technical field of boiler energy efficiency and environmental protection management. Background Art

[0002] Since the State Council issued the "Action Plan for Air Pollution Prevention and Control" on September 10, 2013, more and more boilers have adopted ultra-low emissions to control the emission of air pollutants. Especially in recent years, in order to control haze, the requirements for boiler air pollutant emission control have become increasingly stringent, which has also put forward new requirements for energy conservation and environmental protection. That is to say, under the premise of ensuring the requirements for air pollutant emission control, within the scope permitted by technical conditions, try to save energy and reduce costs.

[0003] Boiler air pollutant emissions mainly control or treat NO x 、SO 2 In actual use, in the treatment of SO 2 There are many technical routes that can be used. For example, in the desulfurization of circulating fluidized bed boilers, in-furnace desulfurization, a combination of in-furnace desulfurization and external desulfurization, external desulfurization, etc. can be used. Which desulfurization technical route can achieve both SO 2 The control standard requirements and energy saving or cost reduction are important technical fields. For the emission of smoke (particulate matter), the currently available technologies mainly include bag filter, electric bag filter, wet electrostatic and the combination of the above. Which method is used to save energy and reduce costs is also an important issue to achieve energy conservation and emission reduction. NO x Ultra-low emission is a typical application of the combination of in-furnace control and out-furnace treatment. After the furnace is controlled by low-nitrogen combustion and other methods, the cost of out-furnace treatment will be significantly reduced, saving material resources and energy. At the same time, it is also necessary to consider the reasonable range of low-nitrogen combustion, that is, the impact of low-nitrogen combustion on boiler combustion efficiency.

[0004] Therefore, developing a technical route that can provide a technical route for controlling and treating air pollutant emissions at the beginning of the design, and can also provide a technical route for energy saving and cost reduction in transformation and operation, has become an urgent problem that needs to be solved by technical personnel in this field. Summary of the invention

[0005] The purpose of the present invention is to propose an evaluation method combining boiler energy efficiency with economic and technical performance for coupled pollutant emission reduction, so as to solve the problems existing in the prior art.

[0006] A method for evaluating boiler energy efficiency and economic and technical performance in coupling pollutant emission reduction, the method being an evaluation method based on unit direct or indirect costs, comprising the following steps:

[0007] S100, calculating the desulfurization cost and the desulfurization unit energy consumption;

[0008] S200, calculating the denitration cost and the denitration unit energy consumption;

[0009] S300, calculating the dust removal cost and the unit energy consumption of the dust removal;

[0010] S400, calculating the cost of waste heat recovery energy saving, energy saving profit and waste heat recovery net unit discount saving;

[0011] S500. Add the desulfurization cost, denitrification cost, dust removal cost, waste heat recovery energy saving cost and energy saving cost to form the final cost; add the unit discounted energy consumption of desulfurization, denitrification and dust removal and the net unit discounted savings of waste heat recovery to form the final unit discounted energy consumption.

[0012] Furthermore, in S100, the desulfurization economic index evaluation process includes the following steps:

[0013] S110, firstly set the calcium-sulfur molar ratio, when the calcium-sulfur molar ratio is ≤2.0, directly calculate the desulfurization cost in the furnace; when 2.0<calcium-sulfur molar ratio≤2.5, calculate the desulfurization heat loss, obtain the increase of fuel consumption cost by calculating the desulfurization heat loss, and then calculate the desulfurization cost in the furnace; when the calcium-sulfur molar ratio is ≥2.5, calculate the desulfurization heat loss, obtain the increase of fuel consumption cost, and calculate the desulfurization cost in the furnace;

[0014] S120, calculate the SO at the inlet of the desulfurization facility under different calcium-sulfur molar ratio conditions 2 Concentration: calculate the semi-dry desulfurization cost and wet desulfurization cost according to the imported concentration, and calculate other costs at the same time;

[0015] S130, respectively calculating the furnace desulfurization cost plus the semi-dry desulfurization cost including other costs, and the furnace desulfurization cost plus the wet desulfurization cost including other costs under different calcium-sulfur ratio conditions;

[0016] S140. Compare the total cost differences under different calcium-sulfur molar ratios, select the lowest total cost, and form an optimized design and operation technology route.

[0017] Furthermore, the other expenses include depreciation costs, maintenance costs, labor costs and financial costs.

[0018] Furthermore, in S100, the desulfurization energy efficiency index evaluation process includes the following steps:

[0019] S150, setting the calcium-sulfur molar ratio. When the calcium-sulfur molar ratio is ≤2.0, directly calculate the unit standard energy consumption of desulfurization in the furnace; when 2.0<calcium-sulfur molar ratio≤2.5, perform desulfurization heat loss calculation, obtain the energy consumption increase of fuel consumption by calculating the desulfurization heat loss, and then calculate the desulfurization energy consumption in the furnace; when the calcium-sulfur molar ratio is ≥2.5, it is necessary to calculate the desulfurization heat loss, obtain the energy consumption increase of fuel consumption, and calculate the unit standard energy consumption of desulfurization in the furnace;

[0020] S160, calculate the SO at the inlet of the desulfurization facility under different calcium-sulfur molar ratio conditions 2 Concentration: calculate the unit energy consumption of semi-dry desulfurization and wet desulfurization according to the imported concentration, and calculate the unit energy consumption of other consumption at the same time;

[0021] S170, respectively calculating the unit energy consumption of furnace desulfurization plus the unit energy consumption of semi-dry desulfurization, and the unit energy consumption of furnace desulfurization plus the unit energy consumption of wet desulfurization under different calcium-sulfur ratios;

[0022] S180. Compare the unit energy consumption under different calcium-sulfur molar ratios, select the lowest unit energy consumption, and form an optimized design and operation technology route.

[0023] Furthermore, in S200, the denitrification economic index evaluation process includes the following steps:

[0024] S210, first set the denitration facility inlet NO x Concentration index, when low nitrogen combustion technology is adopted, NO x ≤100mg / Nm3, directly calculate the denitration cost of SNCR in the furnace or SCR at the tail end; when 100<NO x When NO ≤200mg / Nm3, the heat loss of denitrification is calculated. By calculating the heat loss of denitrification, the cost increase of fuel consumption is obtained, and then the SNCR or SCR denitrification cost is calculated; when NO x When the concentration is greater than 200 mg / Nm3, it is necessary to calculate the heat loss of denitration, obtain the cost increase of fuel consumption, and calculate the cost of SNCR or SCR denitration;

[0025] S220, calculate the different NO inlet of denitrification facilities separately x The cost of low-nitrogen combustion plus SNCR denitrification and the cost of low-nitrogen combustion plus SCR denitrification;

[0026] S230. Compare the costs under different inlet NOx concentrations and the same outlet concentration index conditions, select the lowest cost, and form an optimized design and operation technology route.

[0027] Furthermore, in S200, the denitration energy efficiency index evaluation process includes the following steps:

[0028] S240, first set the denitrification facility entrance NO x Concentration index, when low nitrogen combustion technology is adopted, NO x ≤100mg / Nm3, directly calculate the unit energy consumption of SNCR or tail SCR denitrification in the furnace; when 100<NO x When NO ≤200mg / Nm3, the heat loss of denitrification is calculated. By calculating the heat loss of denitrification, the energy consumption increase of fuel consumption is obtained, and then the unit energy consumption of SNCR or SCR denitrification is calculated; when NO x When the concentration is greater than 200mg / Nm3, it is necessary to calculate the heat loss of denitration, obtain the unit energy consumption increase of fuel consumption, and calculate the unit energy consumption of SNCR or SCR denitration;

[0029] S250, calculate the different NO inlet of denitrification facilities separately x The unit energy consumption of low-nitrogen combustion plus SNCR denitrification and the unit energy consumption of low-nitrogen combustion plus SCR denitrification are as follows;

[0030] S260, compare different inlet NO x Concentration index, same outlet NO x The unit standard energy consumption under the concentration index conditions forms the optimized design or operation technology route.

[0031] Furthermore, in S300, the dust removal economic evaluation process is specifically as follows: the dust removal technical route is optimized for different furnace types: different furnace types use a combination of bag dust removal, electrostatic dust removal and wet dust removal for dust removal, and the costs of different combinations of the above dust removal methods are calculated respectively, and the lowest cost is selected to form an optimized design and operation technical route.

[0032] Furthermore, in S400, the waste heat recovery evaluation process is specifically as follows: for the exhaust gas temperature quality, according to the proportion of waste heat recovery of high-temperature flue gas in front of the desulfurization tower of different furnace types and waste heat recovery during the desulfurization process, the costs and energy saving profits of different recovery methods are calculated respectively.

[0033] Furthermore, the different furnace types include: layer-fired boilers, pulverized coal boilers and circulating fluidized bed boilers.

[0034] The main advantages of the present invention are: the present invention proposes a method for evaluating the energy efficiency of boilers coupled with pollutant emission reduction and economic and technical performance, and evaluates various technical combinations by comprehensively considering the coordination of atmospheric pollutant treatment inside and outside the furnace, and the coordination of low-temperature and high-temperature waste heat recovery. The traditional boiler energy efficiency evaluation method does not consider the significant impact of atmospheric pollutant control inside the boiler furnace on the energy consumption of the boiler system. The present invention comprehensively considers the comprehensive energy efficiency after the coordination of in-furnace control and out-furnace treatment, constructs a coordinated mechanism of efficient and low-nitrogen combustion, efficient desulfurization and low-nitrogen combustion inside the furnace, proposes a technical route that matches the control of atmospheric pollutants inside the furnace with the treatment of tail gas and can achieve long-term operation, forms a coordination method for the recovery of flue gas waste heat and desulfurization waste heat, and develops a comprehensive consideration of the boiler body efficiency, waste heat recovery and atmospheric pollutant treatment optimization design and operation method, which is of great significance to improving the level of atmospheric pollutant treatment and reducing the operating energy consumption of atmospheric pollutant emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a method for evaluating the economic efficiency of desulfurization;

[0036] Figure 2 It is a desulfurization energy efficiency evaluation method;

[0037] Figure 3 It is a method for evaluating the economic efficiency of denitrification;

[0038] Figure 4 It is a method for evaluating the energy efficiency of denitrification. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The economic and technical evaluation of boilers includes the comprehensive use of the control of atmospheric pollutants inside the furnace, the treatment of atmospheric pollutants outside the furnace, the coordinated control inside and outside the furnace, and the coordination of waste heat recovery of high-temperature flue gas and low-temperature flue gas. There are two ways to evaluate the economic and technical evaluation of boilers, one is the evaluation method based on unit direct or indirect costs, and the other is the evaluation method based on unit energy consumption. The present invention evaluates the application of various technical combinations by comprehensively considering the coordination of atmospheric pollutant treatment inside and outside the furnace, and the coordination of waste heat recovery of low temperature and high temperature.

[0041] Control of atmospheric pollutants in the furnace includes NO x 、SO 2 Control, NO x Low nitrogen combustion technology, SNCR, etc. are generally used for control. 2Control generally uses in-furnace limestone desulfurization, etc.

[0042] Treatment of atmospheric pollutants outside the furnace, including NO x 、SO 2 and particulate matter control, NO x Treatment generally adopts SCR technology, ozone method, etc. 2 Treatment generally adopts wet desulfurization, semi-dry desulfurization, etc.

[0043] The control of particulate matter outside the furnace generally adopts bag dust removal, electrostatic dust removal, and a combination of bag and electrostatic dust removal.

[0044] The waste heat recovery of high-temperature flue gas generally adopts a partition-type heat exchanger, and the waste heat recovery of low-temperature flue gas after desulfurization generally adopts a direct contact heat exchanger.

[0045] NO x The core concept is to optimize the NO inside and outside the furnace. x The technical route of coordinated control and governance coordinates the relationship between efficient combustion and low pollutant emissions, and scientifically sets NO x Original emission concentration, through the furnace NO x Reasonable setting of scientific indicators and calculation of technical economy or energy consumption.

[0046] Layer-fired boiler furnace control technology gives priority to fuel distribution, combustion atmosphere organization, flue gas recirculation, fly ash recirculation, etc., tail or outside the furnace NO x SCR technology is preferred as the treatment technology, but other technologies may also be used.

[0047] Low nitrogen combustion technology is preferred for internal control of pulverized coal boilers, and NO x SCR technology is preferred as the treatment technology, but other technologies may also be used.

[0048] The air pollutant control technology for circulating fluidized bed boilers preferably adopts the method of combining low nitrogen combustion technology with SNCR technology. x The treatment technology can adopt SCR technology or ozone oxidation technology.

[0049] SO 2 Coordinated evaluation of in-furnace control and out-furnace governance. The core concept is to follow the principle of suitability and choose whether in-furnace desulfurization technology is needed according to the furnace type. For out-furnace desulfurization, semi-dry or wet desulfurization technology is preferred, and the technical route is arranged reasonably.

[0050] Particle control and treatment technology. The core concept is to arrange different particle removal technology routes according to emission requirements and optimize the configuration of removal equipment.

[0051] The waste heat of high-temperature flue gas and low-temperature flue gas are recovered in coordination. High-temperature flue gas mainly refers to the outlet of boiler air preheater and the inlet of the first-stage dust collector; low-temperature flue gas mainly refers to the waste heat of flue gas in the desulfurization tower. The core concept of the evaluation is to optimize the combination of waste heat recovery of high-temperature flue gas and low-temperature flue gas.

[0052] Comprehensive evaluation. The core concept is to comprehensively consider boiler combustion efficiency, waste heat recovery, etc. according to emission requirements, with the focus on evaluating the impact of different air pollutant control and treatment methods and waste heat recovery methods on boiler energy efficiency, and providing optimized air pollutant emission reduction and waste heat recovery design solutions and operation methods. Under the condition of meeting the air pollutant emission targets, after optimizing the technical route, calculate the comprehensive energy consumption and economic indicators of the boiler and its system.

[0053] Data source: If it is the design stage, the design data can be used for evaluation. The design data mainly include boiler thermal calculation, initial emission of atmospheric pollutants, smoke and wind resistance calculation (or fan selection), hydraulic calculation (or water pump selection), SNCR design data, SCR design data, in-furnace desulfurization design data, out-furnace desulfurization design data, dust removal design data, etc. If it is the operation stage, the actual test data can be used for evaluation. The test data mainly include boiler combustion efficiency, boiler thermal efficiency, initial emission of atmospheric pollutants, SNCR denitrification reaction resources and energy consumption, SCR denitrification reaction resources and energy consumption, in-furnace desulfurization reaction resources and energy consumption, out-furnace desulfurization reaction resources and energy consumption, dust removal resources and energy consumption, etc.

[0054] Reference Figure 1 As shown, a method for evaluating boiler energy efficiency and economic and technical performance in coupling pollutant emission reduction is provided, wherein the evaluation method is an evaluation method based on unit direct or indirect cost, and comprises the following steps:

[0055] S100, calculating the desulfurization cost and the desulfurization unit energy consumption;

[0056] S200, calculating the denitration cost and the denitration unit energy consumption;

[0057] S300, calculating the dust removal cost and the unit energy consumption of the dust removal;

[0058] S400, calculating the cost of waste heat recovery energy saving, energy saving profit and waste heat recovery net unit discount saving;

[0059] S500. Add the desulfurization cost, denitrification cost, dust removal cost, waste heat recovery energy saving cost and energy saving profit to form the final cost or profit; add the unit discounted energy consumption of desulfurization, denitrification and dust removal and the net unit discounted savings of waste heat recovery to form the final unit discounted energy consumption or discounted savings.

[0060] Furthermore, in S100, the desulfurization economic index evaluation process includes the following steps:

[0061] S110. First, the calcium-sulfur molar ratio is set. When the calcium-sulfur molar ratio is ≤2.0, the furnace desulfurization cost is directly calculated. When 2.0<calcium-sulfur molar ratio≤2.5, it is recommended to calculate the desulfurization heat loss. Alternatively, the furnace desulfurization cost can be directly calculated. By calculating the desulfurization heat loss, the increase in fuel consumption cost is obtained, and then the furnace desulfurization cost is calculated. When the calcium-sulfur molar ratio is ≥2.5, the desulfurization heat loss is calculated, the increase in fuel consumption cost is obtained, and the furnace desulfurization cost is calculated.

[0062] S120, calculate the SO at the inlet of the desulfurization facility under different calcium-sulfur molar ratio conditions 2 Concentration: calculate the semi-dry desulfurization cost and wet desulfurization cost according to the imported concentration, and calculate other costs at the same time;

[0063] S130, respectively calculating the furnace desulfurization cost plus the semi-dry desulfurization cost including other costs, and the furnace desulfurization cost plus the wet desulfurization cost including other costs under different calcium-sulfur ratio conditions;

[0064] S140. Compare the total cost differences under different calcium-sulfur molar ratios to form an optimized design or operation technology route.

[0065] Furthermore, in S100, the desulfurization energy efficiency index evaluation process includes the following steps:

[0066] S150, set the calcium-sulfur molar ratio. When the calcium-sulfur molar ratio is ≤2.0, directly calculate the unit standard energy consumption of desulfurization in the furnace; when 2.0<calcium-sulfur molar ratio≤2.5, it is recommended to calculate the desulfurization heat loss. You can also choose to directly calculate the unit energy consumption of desulfurization in the furnace (the problem here is the same as above). By calculating the desulfurization heat loss, the energy consumption increase of fuel consumption is obtained, and then the desulfurization energy consumption in the furnace is calculated; when the calcium-sulfur molar ratio is ≥2.5, it is necessary to calculate the desulfurization heat loss, obtain the energy consumption increase of fuel consumption, and calculate the unit standard energy consumption of desulfurization in the furnace;

[0067] S160, calculate the SO at the inlet of the desulfurization facility under different calcium-sulfur molar ratio conditions 2 Concentration: calculate the unit energy consumption of semi-dry desulfurization and wet desulfurization according to the imported concentration, and calculate the unit energy consumption of other consumption at the same time;

[0068] S170, respectively calculating the unit energy consumption of furnace desulfurization plus the unit energy consumption of semi-dry desulfurization, and the unit energy consumption of furnace desulfurization plus the unit energy consumption of wet desulfurization under different calcium-sulfur ratios;

[0069] S180. Compare the unit energy consumption under different calcium-sulfur molar ratios to form an optimized design or operation technology route.

[0070] Furthermore, in S200, the denitrification economic index evaluation process includes the following steps:

[0071] S210, first set the denitration facility inlet NO x Concentration index, when low nitrogen combustion technology is adopted, NO x ≤100mg / Nm3, directly calculate the denitration cost of SNCR in the furnace or SCR at the tail end; when 100<NO x When NO ≤200mg / Nm3, it is recommended to calculate the heat loss of denitration. You can also choose to directly calculate the SNCR or SCR denitration cost. By calculating the heat loss of denitration, you can get the cost increase of fuel consumption and then calculate the SNCR or SCR denitration cost. x When the concentration is greater than 200 mg / Nm3, it is necessary to calculate the heat loss of denitration, obtain the cost increase of fuel consumption, and calculate the cost of SNCR or SCR denitration;

[0072] S220, calculate the different NO inlet of denitrification facilities separately x The cost of low-nitrogen combustion plus SNCR denitrification and the cost of low-nitrogen combustion plus SCR denitrification;

[0073] S230. Compare the costs under different inlet NOx concentrations and the same outlet concentration index conditions to form an optimized design or operation technology route.

[0074] Furthermore, in S200, the denitration energy efficiency index evaluation process includes the following steps:

[0075] S240, first set the denitrification facility entrance NO x Concentration index, when low nitrogen combustion technology is adopted, NO x ≤100mg / Nm3, directly calculate the unit energy consumption of SNCR or tail SCR denitrification in the furnace; when 100<NO x When NO ≤200mg / Nm3, it is recommended to calculate the heat loss of denitration. You can also choose to directly calculate the unit energy consumption of SNCR or SCR denitration. By calculating the heat loss of denitration, the energy consumption increase of fuel consumption can be obtained, and then the unit energy consumption of SNCR or SCR denitration can be calculated. When NO x When the concentration is greater than 200mg / Nm3, it is necessary to calculate the heat loss of denitration, obtain the unit energy consumption increase of fuel consumption, and calculate the unit energy consumption of SNCR or SCR denitration;

[0076] S250, calculate the different NO inlet of denitrification facilities separately xThe unit energy consumption of low-nitrogen combustion plus SNCR denitrification and the unit energy consumption of low-nitrogen combustion plus SCR denitrification are as follows;

[0077] S260, compare different inlet NO x Concentration index, same outlet NO x The unit standard energy consumption under the concentration index conditions forms the optimized design or operation technology route.

[0078] Furthermore, in S300, the dust removal economic evaluation process is specifically as follows: the dust removal technical route is optimized for different furnace types: different furnace types respectively use a combination of bag dust removal, electrostatic dust removal and wet dust removal for dust removal, and the costs of different dust removal method combinations in the above dust removal methods are calculated respectively to form an optimized design or operation technical route.

[0079] Furthermore, in S400, the waste heat recovery evaluation process is specifically as follows: for the exhaust gas temperature quality, according to the proportion of waste heat recovery of high-temperature flue gas in front of the desulfurization tower of different furnace types and waste heat recovery during the desulfurization process, the costs and energy saving profits of different recovery methods are calculated respectively.

[0080] Furthermore, the different furnace types include: layer-fired boilers, pulverized coal boilers and circulating fluidized bed boilers.

[0081] The following is the calculation method of various data involved in this evaluation method:

[0082] Economic evaluation of in-furnace desulfurization:

[0083] Limestone consumption: The limestone consumption can be calculated using formula (1) during design. Formula (1) can also be used during operation, or the measured limestone consumption data can be used directly.

[0084]

[0085] Where:

[0086] W-limestone consumption, t;

[0087] a-purity of limestone, which can be the test data or 0.9;

[0088] K- Sulfur in solid fuels burns to generate SO 2 The share can be measured by SO 2 After calculation, you can also take 0.9;

[0089] B j -Boiler fuel consumption, measured data or statistical data, t / h;

[0090] S ar - Fuel as received sulfur content, test data, %;

[0091] K glb -Probability molar ratio, measured or set data;

[0092] H- Annual operating time of boiler, measured or expected data.

[0093] Limestone Cost:

[0094]

[0095] Where:

[0096] V 1 -Operating cost (limestone), 10,000 yuan;

[0097] u 1 - Unit price of limestone, yuan / ton;

[0098] Operating power consumption:

[0099] There are two situations, one is to directly purchase limestone powder, and the other is to have a limestone preparation workshop.

[0100]

[0101] V 2 -Operation cost (limestone powder making), 10,000 yuan;

[0102] P t -Total rated power of the motor, kW;

[0103] w Ca - limestone production, t / h;

[0104] P c - Rated power of air compressor, kW;

[0105] β-compression air coefficient, generally 1.92;

[0106] w Ca - Compressed air production, m3 / min;

[0107] B S -Limestone consumption in the furnace, t / h;

[0108] u 2 - Electricity price (on-grid), W / kWh.

[0109] If you purchase limestone powder directly, the electricity consumption for this part of the operation will be zero.

[0110] Energy efficiency evaluation of desulfurization in furnace:

[0111] Operating power consumption: Discounts are made from the perspective of energy consumption.

[0112]

[0113] Where:

[0114] E 2 - Energy consumption of limestone powder production, tons of standard coal;

[0115] -Electricity discount (equivalent value), 0.1229kgce / (kW·h).

[0116] Desulfurization heat loss in the furnace:

[0117] The change in heat loss of the boiler due to the addition of desulfurizer is calculated separately, the desulfurization heat loss under different calcium-sulfur molar ratio conditions in the furnace is calculated separately, and the change in fuel consumption is further calculated.

[0118]

[0119] Where:

[0120] F I - Discounted energy consumption of desulfurization heat loss, t;

[0121] B A - Calculated or measured fuel quantity after adding limestone for desulfurization, t / h;

[0122] B B - Calculated or measured fuel quantity after adding limestone for desulfurization, t / h;

[0123] H- boiler operation hours, h.

[0124] -Discount coefficient, 0.7143kgce / kg.

[0125] Operating costs: The transportation costs of limestone are included in the unit price of limestone and are no longer calculated separately.

[0126] Economic evaluation of wet desulfurization:

[0127] Limestone Cost:

[0128] To calculate the limestone consumption outside the wet flue gas desulfurization furnace, first determine the desulfurization efficiency in the furnace based on the calcium-sulfur molar ratio in the furnace. 2 Emission limit, calculate the desulfurization efficiency that should be achieved outside the furnace. If it is an operating situation, the calcium-sulfur molar ratio outside the furnace can be obtained by combining the power plant test data, which can be calculated by calculating the SO 2 The total amount is the limestone consumption.

[0129] The desulfurization efficiency outside the wet desulfurization furnace is:

[0130]

[0131] Where:

[0132] C SO2 - Wet desulfurization inlet (or furnace desulfurization outlet) SO 2 Concentration, mg / Nm3;

[0133] C-Emission limit, mg / Nm 3 ;

[0134] η tl -Desulfurization efficiency in the furnace, %.

[0135] The cost of limestone outside the wet desulfurization furnace is:

[0136]

[0137] Where:

[0138] K′ glb is the calcium-sulfur molar ratio outside the wet desulfurization furnace, -;

[0139] u′ 1 is the unit price of limestone, Yuan / ton.

[0140] Electricity consumption of wet desulfurization operation:

[0141] The main energy-consuming equipment in the wet flue gas desulfurization process is the slurry circulation pump and oxidation fan, which account for about 60%-70% of the total energy consumption of the desulfurization system. The contribution rate of the desulfurization tower resistance is about 20% of the energy consumption of the induced draft fan. In actual operation, for different desulfurization system inlet SO 2 Concentration, different power circulation pumps will be used to combine to achieve the lowest energy consumption, and this part of the impact is ignored in the calculation here. In addition, no flue gas reheater (GGH) is set. The power consumption cost of the wet desulfurization furnace is:

[0142] V′ 2 =P 1 u' 2 H×10 -4 (8)

[0143] Where:

[0144] P 1 is the total power consumption of the wet flue gas desulfurization system, kW;

[0145] u′ 2 is the electricity price, Yuan / kWh.

[0146] Operating water consumption cost:

[0147] The water consumption points of the desulfurization system mainly include water vapor carried away by flue gas, liquid water carried by flue gas, water carried away by gypsum, and discharged wastewater. The water consumption cost is:

[0148]

[0149] Where:

[0150] B H2O is the water consumption of the external desulfurization system, t;

[0151] u′ 3 The unit price of water use is Yuan / ton.

[0152] Gypsum benefits of wet flue gas desulfurization:

[0153] The industrial byproduct of off-furnace desulfurization is gypsum, the main component of which is crystalline calcium sulfate, and the water content is generally 10% to 20%. The benefits of off-furnace desulfurization gypsum are:

[0154]

[0155] Where:

[0156] After desulfurization in the furnace, SO 2 Remaining amount, t;

[0157] is the moisture content of gypsum, —;

[0158] u′ 4 The selling price of gypsum is Yuan / ton.

[0159] Wastewater treatment costs for wet flue gas desulfurization:

[0160] V′ 5 =B fl u' 5 H×10 -4 (10)

[0161] Where:

[0162] B fl is the desulfurization wastewater treatment capacity, t;

[0163] u′ 5 is the wastewater treatment price, Yuan / ton.

[0164] Energy consumption evaluation of wet desulfurization

[0165] Running power consumption discount

[0166] The main energy-consuming equipment in the wet flue gas desulfurization process is the slurry circulation pump and the oxidation fan, which account for about 60%-70% of the total energy consumption of the total desulfurization system. The contribution rate of the desulfurization tower resistance is about 20% of the energy consumption of the induced draft fan. In actual operation, different power circulation pumps will be combined to achieve the lowest energy consumption for different SO2 concentrations at the inlet of the desulfurization system. This part of the impact is ignored in the calculation here. In addition, there is no flue gas reheater (GGH). The power consumption of the wet flue gas desulfurization furnace is:

[0167]

[0168] Where:

[0169] P1-Total power consumption of wet flue gas desulfurization system, kW.

[0170] -Electricity discount coefficient, 0.1229kgce / kg.

[0171] Operation water consumption discount:

[0172] The water consumption points of the desulfurization system mainly include water vapor carried away by flue gas, liquid water carried by flue gas, water carried away by gypsum, and discharged wastewater. The water consumption cost is:

[0173]

[0174] Where:

[0175] B H2O is the water consumption of the external desulfurization system, t;

[0176] -New water discount coefficient, 0.0875kgce / t.

[0177] Economic evaluation of semi-dry desulfurization:

[0178] The cost of semi-dry limestone outside the furnace is:

[0179]

[0180]

[0181] Where:

[0182] a″ is the purity of quicklime, —;

[0183] K″ glb is the molar ratio of calcium to sulfur outside the semi-dry desulfurization furnace, -;

[0184] u″ 1 is the unit price of quicklime, Yuan / ton.

[0185] Semi-dry operation power consumption:

[0186] Compared with the wet desulfurization process, the semi-dry desulfurization process requires the addition of a high-efficiency bag filter, so it is necessary to consider the contribution of the semi-dry desulfurization system resistance and the bag filter resistance to the induced draft fan power consumption. Existing design data show that the sum of the resistance of the semi-dry desulfurization system and the bag filter is approximately twice the resistance of the wet desulfurization system, so this part of the power consumption is approximately twice the power consumption of the induced draft fan caused by the wet desulfurization resistance. The power consumption cost of the semi-dry desulfurization furnace operation is:

[0187] V″ 2 =P′ 1 u″ 2 H×10 -4 (15)

[0188] Where:

[0189] P′ 1 is the total power consumption of the semi-dry desulfurization system, kW;

[0190] u″ 2 is the electricity price, Yuan / kWh.

[0191] Water consumption cost of semi-dry operation:

[0192]

[0193] Where:

[0194] is the water consumption of the external desulfurization system, t;

[0195] u″ 3 The unit price of water use is Yuan / ton.

[0196] Energy consumption evaluation of semi-dry desulfurization:

[0197] Semi-dry operation power consumption index:

[0198]

[0199] Where:

[0200] P′ 1 -Total power consumption of semi-dry desulfurization system, kW;

[0201] -Electricity discount coefficient, 0.1229kgce / kg.

[0202] Semi-dry operation water consumption discount:

[0203]

[0204] Where:

[0205] -Water consumption of the external desulfurization system, t;

[0206] -New water discount coefficient, 0.0875kgce / t.

[0207] Other expenses, report depreciation costs, repair costs, labor costs, and finance costs.

[0208] Depreciation cost:

[0209] The depreciation period of the desulfurization device is 15 years, and the fixed asset formation rate is 95%. The depreciation cost is:

[0210]

[0211] Where:

[0212] F is the total static investment cost of the desulfurization device, ten thousand yuan;

[0213] n is the number of years the equipment is in use, years.

[0214] Repair costs:

[0215] The maintenance cost is calculated as 3% of the static investment, so the maintenance cost is:

[0216] V 维修 =F×3% (20)

[0217] Labor cost:

[0218] Assuming that each unit adds n operators, and each has an average annual salary of y million yuan, the labor cost is:

[0219] V 人工 =n·y (21)

[0220] Financial costs:

[0221] The financial cost is calculated as 5% of the static investment, so the financial cost is:

[0222] V 财务 =F×5% (22)

[0223] Economic evaluation of denitrification in furnace:

[0224] SNCR denitrification agent (urea) cost:

[0225] The denitrification efficiency is directly related to the ammonia nitrogen molar ratio. According to the value of the inlet flue gas volume, the critical denitrification efficiency that makes the NOx emission value less than 50mg / Nm3 can be calculated, and the required ammonia nitrogen molar ratio can be deduced.

[0226] Ammonia nitrogen molar ratio:

[0227]

[0228] Urea consumption is:

[0229]

[0230] Where:

[0231] η tx is the denitrification efficiency in the furnace, %;

[0232] Bns is urea consumption, t / h;

[0233] γ is the ammonia nitrogen molar ratio, —;

[0234] C NOx is the NOx content at the SNCR inlet, mg / Nm 3 (Calculated based on NO accounting for 95% and NO2 accounting for 5%);

[0235] Vy is the flue gas volume at the SNCR inlet, Nm 3 / h.

[0236] Urea costs are:

[0237] W 1 =B ns v 1 H×10 -4 (25)

[0238] Where:

[0239] v 1 is the unit price of urea, Yuan / ton.

[0240] SNCR water costs:

[0241] Urea needs to be diluted with water to a certain concentration of urea solution before use. The water cost is:

[0242]

[0243] Where:

[0244] b is the concentration of urea solution, —;

[0245] v 2 Water fee, Yuan / ton.

[0246] SNCR operation power consumption cost:

[0247] Determine the denitrification power consumption P2 based on the actual boiler denitrification data. The approximate relationship between power consumption and urea consumption obtained from the operation data statistics is as follows:

[0248] P 2 =20B ns (27)

[0249] The operating power consumption is:

[0250] W 3 =P 2 v 3 H×10 -4 (28)

[0251] Where:

[0252] v 3 is the electricity price, Yuan / kWh.

[0253] Energy consumption evaluation of SNCR denitrification (using urea) in furnace:

[0254] Operation water consumption

[0255]

[0256] Where:

[0257] B ns -Water consumption of the external denitration system, t;

[0258] -New water discount coefficient, 0.0875kgce / t.

[0259] Power consumption

[0260]

[0261] Where:

[0262] -Electricity discount coefficient, 0.1229kgce / kg.

[0263] Heat loss of denitrification in the furnace:

[0264] When the SNCR system uses urea as a reducing agent, the urea solution needs to be diluted and sprayed directly into the reaction area. Obviously, entering the furnace in the form of a solution has a greater impact on boiler efficiency. Therefore, using urea as a reducing agent, the impact of the SNCR denitrification process on boiler efficiency is analyzed.

[0265] After the SNCR reducing agent is sprayed into the furnace, it undergoes the main processes of reducing agent solution evaporation, denitration reaction, and exhaust with flue gas. From the above main processes, it can be summarized that the impact of SNCR technology on boiler efficiency is mainly in the following three aspects: reducing agent solution evaporation endothermic, denitration reaction exothermic and increase in boiler exhaust enthalpy.

[0266] The reducing agent solution evaporates and absorbs heat:

[0267] After the reducing agent solution is sprayed into the furnace, it will go through three main processes: solution absorption of heat, liquid evaporation, and the temperature of the evaporated gas rising to the flue gas temperature.

[0268] The mass flow rate of reducing agent solution is calculated as follows:

[0269]

[0270] The heat absorption of the reducing agent solution from the injection temperature (20°C) to the evaporation temperature (100°C) is calculated as follows:

[0271]

[0272] The reducing agent solution then enters the evaporation process, and the evaporation heat absorption is calculated as follows:

[0273]

[0274] After the reducing agent solution evaporates, its steam continues to absorb heat and eventually reaches the same temperature as the exhaust gas temperature. The heat absorption calculation formula for this process is as follows:

[0275]

[0276] In summary, the total heat absorption during the whole process of evaporation of the reducing agent solution is calculated as follows:

[0277] q 1 =q a +q b +q c (35)

[0278] Denitrification reaction exothermic:

[0279] The reaction equation between urea and NOx in the SNCR system is as follows:

[0280]

[0281]

[0282] HNO, HNO 2 are the reaction heats corresponding to the two reactions. Both reactions are exothermic reactions, and the calculation formula for the heat release of the denitrification reaction is as follows:

[0283]

[0284] Boiler exhaust enthalpy change:

[0285] After the reducing agent solution is sprayed into the furnace, the water vapor, CO2 and N2 generated by the reaction will increase the flue gas volume, causing the boiler flue gas exhaust enthalpy to increase, thereby increasing the exhaust loss and causing the overall boiler efficiency to decrease. Existing studies have shown that the effect of boiler exhaust enthalpy changes on boiler efficiency is very small and can be ignored.

[0286] The heat loss of denitrification can also be approximately calculated according to the following provisions:

[0287] When the inlet NOx concentration is ≤00mg / m3 and the denitrification efficiency is above 40%, the total heat loss of denitrification is calculated as 0.1%, and the increase in fuel volume is calculated as 0.11%Bj, and the discounted price is 0.11B j 0.7413; when the inlet 100 is less than the NOx concentration ≤ 300 mg / m3, and the denitrification efficiency is more than 40%, the total heat loss of denitrification is calculated as 0.4%, and the increase in fuel volume is calculated as 0.44% Bj, and the discounted price is 0.44 B j 0.7413; When the inlet NOx concentration is greater than 300mg / m3 and the denitration efficiency is above 40%, the total heat loss of denitration is calculated as 1%, and the increase in fuel volume is calculated as 1.11%Bj, and the discounted price is 1.11B j 0.7413.

[0288] Economic evaluation of SCR denitrification (using liquid ammonia):

[0289] SCR denitration (using liquid ammonia) reducing agent cost:

[0290] When liquid ammonia is used in SCR, the denitrification efficiency can reach 90% when the ammonia-nitrogen molar ratio is 0.9. Therefore, the following ammonia-nitrogen molar ratio is 0.9, which can meet the emission requirements.

[0291] Liquid ammonia consumption is:

[0292]

[0293] Where:

[0294] is the consumption of liquid ammonia, t / h;

[0295] γ′ is the molar ratio of ammonia to nitrogen, —.

[0296] The cost of liquid ammonia is:

[0297]

[0298] In the formula,

[0299] v' 1 is the unit price of liquid ammonia, Yuan / ton.

[0300] SCR denitrification (using liquid ammonia) operating power consumption:

[0301] The main power-consuming equipment in the SCR liquid ammonia denitrification process includes the liquid ammonia unloading compressor, liquid ammonia pump, dilution fan and wastewater pump. This standard treats the shaft power of fixed continuous operation equipment and the power consumption of other equipment separately according to the change of liquid ammonia amount. Determine the power consumption P′ of denitrification based on boiler operation data. 2 , then the power consumption is:

[0302]

[0303] The operating power consumption is:

[0304] W' 2 =P' 2 v' 2 H×10 -4 (40)

[0305] Where:

[0306] v′ 2 is the electricity price, Yuan / kWh.

[0307] SCR denitrification (using liquid ammonia) steam consumption cost

[0308] Steam is consumed for soot blowing and heating the reducing agent. The cost of steam consumption is:

[0309] W′ 3 =sv' 3 H×10 -4 (40)

[0310] Where:

[0311] s is the steam consumption per hour, t / h;

[0312] v′ 3 is the steam price, Yuan / ton (180 Yuan / ton can be taken here).

[0313] SCR denitrification (using liquid ammonia) catalyst cost

[0314] The operating cost of the SCR denitration (using liquid ammonia) catalyst is:

[0315]

[0316] In the formula,

[0317] V is the annual replacement volume of the catalyst, m3;

[0318] h is the life cycle of the catalyst, h;

[0319] v′ 4 is the catalyst price, Yuan / m3.

[0320] SCR denitrification (using liquid ammonia) other costs

[0321] SCR denitrification (using liquid ammonia) depreciation cost

[0322] The depreciation period of the denitrification device is 15 years, and the fixed asset formation rate is 95%. The depreciation cost is:

[0323]

[0324] Where:

[0325] F is the total static investment cost of the denitrification device, ten thousand yuan;

[0326] n is the number of years the equipment is in use, years.

[0327] SCR denitrification (using liquid ammonia) maintenance cost:

[0328] The maintenance cost is calculated as 3% of the static investment, so the maintenance cost is:

[0329] V 维修 =F×3% (43)

[0330] SCR denitrification (using liquid ammonia) labor cost

[0331] Assuming that each unit adds n operators, and each has an average annual salary of y million yuan, the labor cost is:

[0332] V 人工 =n·y (44)

[0333] SCR denitrification (using liquid ammonia) financial costs

[0334] The financial cost is calculated as 5% of the static investment, so the financial cost is:

[0335] V 财务 =F×5% (45)

[0336] Energy consumption evaluation of SCR denitrification (using liquid ammonia)

[0337] SCR denitrification (using liquid ammonia) operating power consumption standard energy consumption

[0338] The main power-consuming equipment in the SCR liquid ammonia denitrification process includes the liquid ammonia unloading compressor, liquid ammonia pump, dilution fan and wastewater pump. This standard treats the shaft power of fixed continuous operation equipment and the power consumption of other equipment separately according to the change of liquid ammonia amount. Determine the power consumption P′ of denitrification based on boiler operation data. 2 , then the power consumption is:

[0339]

[0340] Where:

[0341] P′ g -Fixed continuous operation equipment shaft power, kwh.

[0342] The operating power consumption is discounted as follows:

[0343]

[0344] Where:

[0345] -Electricity discount factor, 0.1229kgce / (kWh).

[0346] SCR denitrification (using liquid ammonia) steam consumption discount

[0347] Steam is consumed for soot blowing and heating the reducing agent. The cost of steam consumption is:

[0348]

[0349] Where:

[0350] s is the steam consumption per hour, t / h;

[0351] - Steam standard reduction factor, 0.1286kgce / (kWh).

[0352] Economic and energy efficiency evaluation of coupled dust removal process

[0353] Economic Evaluation of Bag Dust Collector

[0354] If it is the design stage, the increased power of the induced draft fan caused by resistance, the increased power consumption of the compressed air system, and the power consumption of the dust collector operation can be calculated based on the design data. If it is the operation stage, the increased power of the induced draft fan caused by resistance, the increased power consumption of the compressed air system, and the power consumption of the dust collector operation can be calculated based on the operation data.

[0355] Increased power consumption cost of induced draft fan due to resistance

[0356] W bdc1 =ΔpQv bdc1 H×10 -4 / 0.85 (49)

[0357] Where:

[0358] W bdc1 -Operational expenses, 10,000 yuan;

[0359] Δp-dust collector inlet and outlet pressure difference, Pa;

[0360] Q-dust collector inlet air volume, m3 / s;

[0361] v bdc1 -Electricity price, RMB / kWh.

[0362] Increased power consumption costs of compressed air systems

[0363] W bdc2 =0.746P adc2 Hv adc2 [R adc2 +R′ adc2 ]×10 -4 / 0.9 (50)

[0364] Where:

[0365] W bdc2 -Operational expenses, 10,000 yuan;

[0366] P adc2 - Full load horsepower of the motor, hp;

[0367] v bdc2 -Electricity price, RMB / kWh;

[0368] R adc2 -Full load operation time ratio, %;

[0369] R′ adc2 -No-load operation time ratio, %.

[0370] Energy Consumption Evaluation of Bag Dust Collector

[0371] Increased power consumption of induced draft fan due to resistance

[0372]

[0373] Where:

[0374] -Electricity discount factor, 0.1229kgce / (kWh).

[0375] Increased power consumption discount for compressed air systems

[0376]

[0377] Where:

[0378] -Electricity discount factor, 0.1229kgce / (kWh).

[0379] Economic Evaluation of Electric Bag Precipitator

[0380] The power consumption of the electric bag composite dust collector should be the cumulative power consumption of the electric dust collector and the bag dust collector.

[0381] Power consumption of induced draft fan

[0382] The power consumption cost of the induced draft fan is calculated according to formula (49).

[0383] Increased power consumption costs of compressed air systems

[0384] The additional power consumption cost of the compressed air system is calculated according to formula (50).

[0385] Energy consumption cost of main equipment

[0386] The energy consumption of the electric bag dust collector includes all electrical equipment in the dust removal facility, such as primary and secondary rectifier transformers, frequency conversion equipment, heating devices, etc.

[0387] Energy Consumption Evaluation of Electric Bag Precipitator

[0388] Energy consumption discount of induced draft fan

[0389] The power consumption of the induced draft fan is calculated according to formula (51).

[0390] Increased power consumption costs of compressed air systems

[0391] The additional power consumption and energy consumption discount of the compressed air system is calculated according to formula (52).

[0392] Energy consumption cost of main equipment

[0393] The energy consumption of the electric bag dust collector includes all electrical equipment in the dust removal facility, such as primary and secondary rectifier transformers, frequency conversion equipment, heating devices, etc.

[0394] Economic Evaluation of Wet Electrostatic Precipitator

[0395] Dust collector resistance power consumption cost

[0396] The dust collector resistance power consumption cost is calculated according to formula (49).

[0397] Other electricity consumption costs of dust collector

[0398] The power consumption of the high-voltage power supply equipment and low-voltage power-consuming equipment of the electrostatic precipitator is calculated in hours according to (49).

[0399] Energy Consumption Evaluation of Wet Electrostatic Precipitator

[0400] Energy consumption discount standard of dust collector resistance power consumption

[0401] The dust collector resistance power consumption cost is calculated according to formula (50).

[0402] Energy consumption discount for other power consumption of dust collector

[0403] The power consumption of the high-voltage power supply equipment and low-voltage power-consuming equipment of the electrostatic precipitator is calculated in hours according to (49).

[0404] Other expenses

[0405] Bag filter depreciation cost

[0406] The depreciation period of the denitrification device is 15 years, and the fixed asset formation rate is 95%. The depreciation cost is:

[0407]

[0408] Where:

[0409] F is the total static investment cost of the dust removal device, ten thousand yuan;

[0410] n is the number of years the equipment is in use, years.

[0411] Bag filter maintenance cost

[0412] The maintenance cost is calculated as 3% of the static investment, so the maintenance cost is:

[0413] V 维修 =F×3% (54)

[0414] Bag filter labor cost

[0415] Assuming that each unit adds n operators, and each has an average annual salary of y million yuan, the labor cost is:

[0416] V 人工 =n·y (55)

[0417] Economic evaluation of waste heat utilization from desulfurization

[0418] The input required for the evaluation of the utilization of desulfurization waste heat is shown in Table 1, and the calculation part is shown in Table 2.

[0419]

[0420]

[0421] Table 1 Economic evaluation of desulfurization waste heat utilization

[0422] Calculation part

[0423]

[0424]

[0425]

[0426] Table 2 Calculation of energy resource consumption for desulfurization waste heat utilization

[0427] Energy resource consumption calculation

[0428]

[0429]

[0430] Table 3 Economic evaluation calculation of desulfurization waste heat utilization

[0431] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An evaluation method combining boiler energy efficiency and economic and technical performance for coupled pollutant emission reduction, It is characterized in that The evaluation method is an evaluation method based on unit energy consumption, comprising the following steps: S100, calculating the desulfurization cost and the desulfurization unit energy consumption; In S100, the following steps are included: S150, SO in the furnace 2 Control the use of limestone desulfurization in the furnace, set the calcium-sulfur molar ratio, and when the calcium-sulfur molar ratio is ≤2.0, directly calculate the unit standard energy consumption of desulfurization in the furnace; when 2.0<calcium-sulfur molar ratio≤2.5, calculate the desulfurization heat loss, and obtain the energy consumption increase of fuel consumption by calculating the desulfurization heat loss, and then calculate the unit standard energy consumption of desulfurization in the furnace; when the calcium-sulfur molar ratio is ≥2.5, calculate the desulfurization heat loss, obtain the energy consumption increase of fuel consumption, and calculate the unit standard energy consumption of desulfurization in the furnace; S160, calculate the SO at the inlet of the desulfurization facility under different calcium-sulfur molar ratio conditions 2 Concentration, according to inlet SO 2 The unit energy consumption of semi-dry desulfurization and the unit energy consumption of wet desulfurization are calculated based on the concentration. S170, respectively calculating the unit energy consumption of furnace desulfurization plus the unit energy consumption of semi-dry desulfurization, and the unit energy consumption of furnace desulfurization plus the unit energy consumption of wet desulfurization under different calcium-sulfur molar ratios; S180. Compare the difference between the unit energy consumption of furnace desulfurization plus the unit energy consumption of semi-dry desulfurization and the unit energy consumption of furnace desulfurization plus the unit energy consumption of wet desulfurization under different calcium-sulfur molar ratios, select the lowest unit energy consumption of desulfurization, and form an optimized design and operation technology route; S200, calculating the denitration cost and the denitration unit energy consumption; In S200, the following steps are included: S240, first set the denitration facility entrance NO x Concentration index, when low nitrogen combustion technology is adopted, NO x ≤100mg / Nm 3 When SNCR technology or tail SCR technology denitrification unit energy consumption is directly calculated; when 100<NO x ≤200mg / Nm 3 When NO x >200mg / Nm 3 When calculating the heat loss of denitrification, the unit discounted energy consumption increase of fuel consumption is obtained, and the unit discounted energy consumption of denitrification of SNCR technology or tail SCR technology is calculated; S250, calculate the different NO inlet of denitrification facilities separately x Under the concentration, the unit standard energy consumption of low nitrogen combustion plus SNCR technology denitrification, and the unit standard energy consumption of low nitrogen combustion plus tail SCR technology denitrification; S260, compare the different NO inlet of denitrification facilities x Concentration, same outlet NO x Under the concentration index conditions, the difference between the unit energy consumption of low-nitrogen combustion plus SNCR technology denitrification and the unit energy consumption of low-nitrogen combustion plus tail SCR technology denitrification is selected to form an optimized design and operation technology route; S300, calculating the dust removal cost and the unit energy consumption of the dust removal; S400, calculating the cost of waste heat recovery energy saving, energy saving profit and waste heat recovery net unit discount saving; S500. Add the desulfurization cost, denitrification cost, dust removal cost, waste heat recovery energy saving cost and energy saving cost to form the final cost; add the desulfurization unit discounted energy consumption, denitrification unit discounted energy consumption, dust removal unit discounted energy consumption and waste heat recovery net unit discounted energy consumption to form the final unit discounted energy consumption.

2. According to claim 1, a method for evaluating boiler energy efficiency and economic and technical performance in coupling pollutant emission reduction, It is characterized in that In S100, the desulfurization economic index evaluation process includes the following steps: S110, firstly set the calcium-sulfur molar ratio, when the calcium-sulfur molar ratio is ≤2.0, directly calculate the desulfurization cost in the furnace; when 2.0<calcium-sulfur molar ratio≤2.5, calculate the desulfurization heat loss, obtain the increase of fuel consumption cost by calculating the desulfurization heat loss, and then calculate the desulfurization cost in the furnace; when the calcium-sulfur molar ratio is ≥2.5, calculate the desulfurization heat loss, obtain the increase of fuel consumption cost, and calculate the desulfurization cost in the furnace; S120, calculate the SO at the inlet of the desulfurization facility under different calcium-sulfur molar ratio conditions 2 Concentration, according to inlet SO 2 The semi-dry desulfurization cost and wet desulfurization cost are calculated based on the concentration, and other expenses are calculated at the same time, and the other expenses are depreciation cost, maintenance cost, labor cost and financial cost; S130, respectively calculating the furnace desulfurization cost plus the semi-dry desulfurization cost including other costs, and the furnace desulfurization cost plus the wet desulfurization cost including other costs under different calcium-sulfur molar ratio conditions; S140. Compare the difference between the in-furnace desulfurization cost under different calcium-sulfur molar ratios plus the semi-dry desulfurization cost including other costs and the in-furnace desulfurization cost plus the wet desulfurization cost including other costs, select the lowest cost, and form an optimized design and operation technical route.

3. The evaluation method for combining boiler energy efficiency and economic and technical performance for coupled pollutant emission reduction according to claim 1, It is characterized in that In S200, the denitrification economic index evaluation process includes the following steps: S210, first set the denitration facility inlet NO x Concentration index, when low nitrogen combustion technology is adopted, NO x ≤100mg / Nm 3 When 100<NO x ≤200mg / Nm 3 When NO is used, the heat loss of denitrification is calculated. By calculating the heat loss of denitrification, the cost increase of fuel consumption is obtained, and then the denitrification cost of SNCR technology or tail SCR technology is calculated; when NO x >200mg / Nm 3 When calculating the heat loss of denitrification, the cost increase of fuel consumption is obtained, and the denitrification cost of SNCR technology or tail SCR technology is calculated; S220, calculate the different NO inlet of denitrification facilities separately x Under the concentration, the cost of denitrification of low nitrogen combustion plus SNCR technology, and the cost of denitrification of low nitrogen combustion plus tail SCR technology; S230, compare different inlet NO x Concentration, same outlet NO x Based on the difference in denitrification costs between low-nitrogen combustion plus SNCR technology and low-nitrogen combustion plus tail SCR technology under concentration index conditions, the lowest cost is selected to form an optimized design and operation technology route.

4. The evaluation method for combining boiler energy efficiency and economic and technical performance for coupled pollutant emission reduction according to claim 1, It is characterized in that In S300, the dust removal economic evaluation process is as follows: Optimize the dust removal technology route for different furnace types: Different furnace types use a combination of bag dust removal, electrostatic dust removal, and wet dust removal for dust removal, calculate the cost of different dust removal method combinations, select the lowest cost, and form an optimized design and operation technology route.

5. The evaluation method for combining boiler energy efficiency and economic and technical performance for coupled pollutant emission reduction according to claim 1, It is characterized in that In S400, the waste heat recovery evaluation process is specifically as follows: for the exhaust gas temperature quality, according to the proportion of waste heat recovery of high-temperature flue gas in front of the desulfurization tower of different furnace types and waste heat recovery during the desulfurization process, the costs and energy saving profits of different recovery methods are calculated respectively.

6. A method for evaluating boiler energy efficiency and economic and technical performance in coupling pollutant emission reduction according to claim 4 or 5, It is characterized in that The different boiler types include: layer-fired boilers, pulverized coal boilers and circulating fluidized bed boilers.

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