A method for testing and calculating the impact value of boiler efficiency with a bypass flue gas drying tower

Abstract

The present invention discloses a bypass flue gas drying tower boiler efficiency impact value test and calculation method, comprising the following steps: 1) taking the basic low calorific value Q received by the coal powder fed into the boiler as the d As the input heat of the boiler; 2) measure the inlet temperature of the blower t 0 , while measuring the exhaust gas temperature of the air preheater when the unit is running and the bypass flue gas drying tower is not in operation py and flue gas flow V py , using flue gas analyzer to test N in flue gas 2 , O 2 , CO 2 , H 2 The volume fraction of O#imgabs0# is used to calculate the exhaust loss Q 2 ; 3) Keep the same operating conditions, put the bypass flue gas drying tower into operation, and after it stabilizes, measure the flow rate V of the flue gas extracted by the bypass flue gas drying tower. 旁 and temperature θ ky , and measure the flue gas flow rate V′ at the outlet of the air preheater py and temperature θ′ py , to calculate the exhaust loss Q′ 2 ; 4) According to Q′ 2 With Q 2 The difference between the values ​​of Δq and Δq is used to calculate the boiler efficiency impact value of the bypass flue gas drying tower. This method can realize the test of the boiler efficiency impact value of the bypass flue gas drying tower.

Description

Technical Field

[0001] The invention belongs to the technical field of zero-discharge of desulfurized wastewater and relates to a method for testing and calculating the efficiency impact value of a bypass flue gas drying tower boiler. Background Art

[0002] Bypass flue gas drying tower technology is a desulfurization wastewater zero discharge technology that has been widely used in recent years. More and more power plants are building and putting into operation bypass flue gas drying towers. Figure 1 As shown, a high temperature of about 300-350°C is extracted from the flue between the denitration SCR device and the air preheater in the boiler flue gas system to the bypass flue gas drying tower. At the same time, the desulfurization wastewater is sent to the tower and the wastewater is atomized into droplets with a particle size of 30-100μm by an atomizer. The droplets are dispersed in the flue gas and quickly evaporate and dry. The moisture enters the flue gas and the tail gas is discharged to the flue after the air preheater and enters the electrostatic precipitator. The residual salt, suspended particles, etc. after the wastewater is evaporated are combined with the fly ash. One part enters the dust collector with the flue gas, and the other part falls into the cone bucket at the bottom of the drying tower and is sent to the ash storage through the ash conveying device.

[0003] However, this technology extracts part of the high-temperature flue gas before the air preheater for wastewater drying, which will have a certain impact on the unit boiler efficiency. Accurately and conveniently testing and calculating the impact value of the bypass flue gas drying tower boiler efficiency is conducive to objectively analyzing and evaluating the actual energy consumption of the bypass flue gas drying technology and the operation management of the power plant. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for testing and calculating the efficiency impact value of a bypass flue gas drying tower boiler, which can realize the test of the efficiency impact value of a bypass flue gas drying tower boiler.

[0005] To achieve the above object, the bypass flue gas drying tower boiler efficiency impact value test and calculation method of the present invention comprises the following steps:

[0006] 1) The basic low calorific value Q received by the pulverized coal fed into the boiler d As input heat to the boiler;

[0007] 2) Measure the inlet temperature t0 of the blower, and at the same time measure the exhaust gas temperature θ of the air preheater when the unit is running and the bypass flue gas drying tower is not in operation py and flue gas flow V py , use the flue gas analyzer to test the volume fraction of N2, O2, CO2, and H2O in the flue gas To calculate the smoke exhaust loss Q2;

[0008] 3) Maintain the same operating conditions, put the bypass flue gas drying tower into operation, and after it stabilizes, measure the flow rate V of the flue gas extracted by the bypass flue gas drying tower.旁 and temperature θ ky , and measure the flue gas flow rate V′ at the outlet of the air preheater py and temperature θ′ py , to calculate the smoke exhaust loss Q′2;

[0009] 4) Calculate the boiler efficiency impact value Δq of the bypass flue gas drying tower based on the difference between Q′2 and Q2.

[0010] The exhaust loss Q2 in step 2) is:

[0011] Among them, V py is the flue gas volume, and They are respectively N2, O2, CO2 and H2O in the flue gas from constant pressure t0 to θ py Specific heat capacity.

[0012] The exhaust loss Q′2 is:

[0013]

[0014] in, and are N2, O2, CO2 and H2O in the flue gas from t0 to θ′ py The specific heat capacity at constant pressure, and are N2, O2, CO2 and H2O in the flue gas from t0 to θ ky Specific heat capacity at constant pressure.

[0015] The boiler efficiency impact value Δq of the bypass flue gas drying tower is:

[0016]

[0017] The present invention has the following beneficial effects:

[0018] The bypass flue gas drying tower boiler efficiency impact value testing and calculation method described in the present invention, during specific operation, measures the flue gas flow rate, temperature, flue gas composition, and flow rate and temperature of the extracted flue gas after the air preheater before and after the bypass flue gas drying tower is put into operation, so as to calculate the boiler efficiency impact value of the bypass flue gas drying tower. The operation is convenient and simple, and there is no need to tediously calculate the boiler efficiency of the entire unit. The actual energy consumption brought about by the commissioning of the bypass flue gas drying tower can be more accurately reflected, which facilitates the inclusion of relevant data into the overall energy consumption management and analysis system of the power plant, and is convenient for decision makers to refer to. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the system schematic diagram of the desulfurization wastewater flue gas drying tower. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0021] The bypass flue gas drying tower boiler efficiency impact value test and calculation method of the present invention comprises the following steps:

[0022] 1) The basic low calorific value Q received by the pulverized coal fed into the boiler d As input heat to the boiler;

[0023] 2) Measure the inlet temperature t0 of the blower, and at the same time measure the exhaust gas temperature θ of the air preheater when the unit is running and the bypass flue gas drying tower is not in operation py and flue gas flow V py , use the flue gas analyzer to test the volume fraction of N2, O2, CO2, and H2O in the flue gas To calculate the smoke exhaust loss Q2;

[0024] The exhaust loss Q2 in step 2) is:

[0025] Among them, V py is the flue gas volume, and They are respectively N2, O2, CO2 and H2O in the flue gas from constant pressure t0 to θ py Specific heat capacity.

[0026] 3) Maintain the same operating conditions, put the bypass flue gas drying tower into operation, and after it stabilizes, measure the flow rate V of the flue gas extracted by the bypass flue gas drying tower. 旁 and temperature θ ky , and measure the flue gas flow rate V′ at the outlet of the air preheater py and temperature θ′ py , to calculate the smoke exhaust loss Q′2;

[0027] The exhaust loss Q′2 is:

[0028]

[0029] in, and are N2, O2, CO2 and H2O in the flue gas from t0 to θ′ py The specific heat capacity at constant pressure, and are N2, O2, CO2 and H2O in the flue gas from t0 to θ ky Specific heat capacity at constant pressure.

[0030] 4) Calculate the boiler efficiency impact value Δq of the bypass flue gas drying tower based on the difference between Q′2 and Q2.

[0031] The boiler efficiency impact value Δq of the bypass flue gas drying tower is:

[0032]

Claims

1. A method for testing and calculating the impact value of a bypass flue gas drying tower boiler efficiency, characterized in that: The following steps are involved: 1) The basic low calorific value Q received by the pulverized coal fed into the boiler d As input heat to the boiler; 2) Measure the inlet temperature t0 of the blower, and at the same time measure the exhaust gas temperature θ of the air preheater when the unit is running and the bypass flue gas drying tower is not in operation py and flue gas flow V py , use the flue gas analyzer to test the volume fraction of N2, O2, CO2, and H2O in the flue gas To calculate the smoke exhaust loss Q2; 3) Maintain the same operating conditions, put the bypass flue gas drying tower into operation, and after it stabilizes, measure the flow rate V of the flue gas extracted by the bypass flue gas drying tower. 旁 and temperature θ ky , and measure the flue gas flow rate V′ at the outlet of the air preheater py and temperature θ′ py , to calculate the smoke exhaust loss Q′2; 4) Calculate the boiler efficiency impact value Δq of the bypass flue gas drying tower based on the difference between Q′2 and Q2; The exhaust loss Q2 in step 2) is: Among them, V py is the flue gas volume, and They are respectively N2, O2, CO2 and H2O in the flue gas from constant pressure t0 to θ py Specific heat capacity; The exhaust loss Q′2 is: in, and are N2, O2, CO2 and H2O in the flue gas from t0 to θ′ py The specific heat capacity at constant pressure, and are N2, O2, CO2 and H2O in the flue gas from t0 to θ ky Specific heat capacity at constant pressure; The boiler efficiency impact value Δq of the bypass flue gas drying tower is:

Images