A performance evaluation method for waste heat boiler of cement kiln

Abstract

The present invention discloses a cement kiln waste heat boiler performance evaluation method, comprising the following steps: S1, measuring the boiler evaporation amount X m , boiler exhaust side pressure loss measurement value P 测量 Correction is performed to obtain the boiler evaporation correction value X and the boiler exhaust gas side pressure loss correction value P 修正 ; S2, based on the boiler evaporation correction value X and the boiler exhaust side pressure loss correction value P 修正 The performance of the cement kiln waste heat boiler is evaluated. If both conditions 1 and 2 are met, the performance of the cement kiln waste heat boiler meets the standard. Otherwise, the performance of the cement kiln waste heat boiler does not meet the standard. Condition 1: The boiler evaporation correction value X is greater than the boiler evaporation guarantee value; Condition 2: The boiler exhaust gas side pressure loss correction value P 修正 The present invention analyzes the performance of the cement kiln waste heat boiler system from two aspects: boiler evaporation correction and boiler waste gas side pressure loss correction, and provides a fair and scientific method for evaluating the performance of waste heat boilers for customers and suppliers.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial production equipment, and more specifically, the present invention relates to a performance evaluation method for a cement kiln waste heat boiler. Background Art

[0002] How to fairly and scientifically evaluate the performance of cement kiln waste heat boilers has always been a difficult problem in the industry. At present, the performance of boilers is roughly evaluated based on the evaporation volume of waste heat boilers at home and abroad. This evaluation method is neither fair nor scientific, and the evaluation indicators are single. It cannot comprehensively analyze the performance of the boiler system, nor can it determine the responsibilities of each participant (engineering design party and equipment supplier). Summary of the invention

[0003] The invention provides a cement kiln waste heat boiler performance evaluation method, which evaluates the cement kiln waste heat boiler system performance from two aspects of boiler evaporation amount and boiler exhaust gas side pressure loss.

[0004] The present invention is implemented as follows: a cement kiln waste heat boiler performance evaluation method, the method specifically comprising the following steps:

[0005] S1, the measured value of boiler evaporation X m , boiler exhaust side pressure loss measurement value P 测量 Correction is performed to obtain the boiler evaporation correction value X and the boiler exhaust gas side pressure loss correction value P 修正 ;

[0006] S2, based on the boiler evaporation correction value X and the boiler exhaust side pressure loss correction value P 修正 Evaluate the performance of the cement kiln waste heat boiler. If both conditions 1 and 2 are met, the performance of the cement kiln waste heat boiler meets the standard. Otherwise, the performance of the cement kiln waste heat boiler does not meet the standard.

[0007] Condition 1: The boiler evaporation correction value X is greater than the boiler evaporation guarantee value;

[0008] Condition 2: Boiler exhaust gas side pressure loss correction value P 修正 Less than the guaranteed value of pressure loss on the boiler exhaust gas side.

[0009] Furthermore, the calculation formula of the boiler evaporation correction value X is as follows:

[0010]

[0011] Where X is the evaporation correction value at the boiler superheater outlet, that is, the boiler evaporation correction value X; X m is the measured value of the evaporation at the boiler superheater outlet, that is, the boiler evaporation measurement value X; A is the evaporation deviation value, which is caused by the deviation between the actual exhaust gas volume at the boiler inlet and the reference exhaust gas volume, and the deviation between the actual exhaust gas temperature and the reference exhaust gas temperature; F wis the boiler feed water temperature correction coefficient; F p is the boiler steam pressure correction factor; F t is the boiler steam temperature correction factor.

[0012] Furthermore, the boiler exhaust side pressure loss correction value P 修正 The calculation formula is as follows:

[0013] P 修正 =P 入修正 +P 出修正 +P 本修正

[0014] Among them, P 修正 P is the correction value of the pressure loss on the boiler exhaust gas side; 入修正 P is the correction value of the pressure loss of the flue gas duct at the boiler inlet; 出修正 P is the correction value of the pressure loss of the flue gas duct at the boiler outlet; 本修正 is the boiler body pressure loss correction value;

[0015] P 入修正 =P 入测量 ×(Vg 参标况入 / Vg 实标况入 ) 2 ×(273.15+T 参考入 ) / (273.15+T 实际入 )×[(P 1 +P 2 ) / 2 / P 基准入 ];

[0016] P 本修正 =P 本测量 ×(Vg 参标况本 / Vg 实标况本 ) 2 ×(273.15+T 参考本 ) / (273.15+T 实际本 )×[(P 2 +P 3 ) / 2 / P 基准本 ];

[0017] P 出修正 =P 出测量 ×(Vg 参标况出 / Vg 实标况出 ) 2 ×(273.15+T 参考出 ) / (273.15+T 实际出 )×[(P 3 +P 4 ) / 2 / P 基准出 ];

[0018] Vg 参标况入Vg is the standard air volume of the inlet duct, 实标况入 Vg is the actual standard air volume of the inlet duct, 参标况出 Vg is the standard air volume of the outlet duct. 实标况出 Vg is the actual standard air volume of the outlet duct, 参标况本 Vg is the standard air volume of the boiler body. 实标况本 is the actual standard air volume of the boiler body; T 参考入 is the reference exhaust gas qualitative temperature of the inlet duct, T 实际入 is the actual exhaust gas qualitative temperature of the inlet duct, T 参考本 is the reference exhaust gas qualitative temperature of the boiler body, T 实际本 is the actual exhaust gas qualitative temperature of the boiler body, T 参考出 is the reference exhaust gas qualitative temperature of the outlet air duct, T 实际出 is the actual exhaust gas qualitative temperature of the outlet air duct; P 基准入 is the design basis exhaust gas pressure of the inlet duct, P 基准本 is the design reference exhaust gas pressure of the boiler body, P 基准出 It is the design base exhaust gas pressure of outlet air duct.

[0019] Furthermore, the boiler exhaust side pressure loss measurement value P 测量 The calculation formula is as follows:

[0020] P 测量 =P 入测量 +P 本测量 +P 出测量

[0021] Among them, P 测量 is the measured value of the pressure loss on the boiler exhaust gas side; P 入测量 is the measured value of the pressure loss of the flue gas duct at the boiler inlet, P 入测量 =(P 1 -P 2 )×1000 / 9.80665;P 出测量 is the measured pressure loss of the flue gas duct at the boiler outlet, P 出测量 =(P 4 -P 3 )×1000 / 9.80665;P 本测量 is the measured value of boiler body pressure loss, P 本测量 =(P 3 -P 2 )×1000 / 9.80665;

[0022] P 1 is the static pressure measurement value at the boiler inlet air duct interface, P 2 is the static pressure measurement value of the boiler body inlet, P 3 is the static pressure measurement value at the boiler outlet, P 4It is the static pressure measurement value at the boiler outlet air duct interface point.

[0023] The present invention analyzes the performance of a cement kiln waste heat boiler system from two aspects of boiler evaporation amount correction and boiler exhaust gas side pressure loss correction, and provides a method for customers and suppliers to fairly and scientifically evaluate the performance of waste heat boilers. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flow chart of a cement kiln waste heat boiler performance evaluation method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The specific implementation modes of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0026] Figure 1 A flow chart of a cement kiln waste heat boiler performance evaluation method provided by an embodiment of the present invention, the method specifically comprises the following steps:

[0027] S1, the measured value of boiler evaporation X m , boiler exhaust side pressure loss measurement value P 测量 Correction is performed to obtain the boiler evaporation correction value X and the boiler exhaust gas side pressure loss correction value P 修正 ;

[0028] S2, based on the boiler evaporation correction value X and the boiler exhaust side pressure loss correction value P 修正 Evaluate the performance of the cement kiln waste heat boiler. If both conditions 1 and 2 are met, the performance of the cement kiln waste heat boiler meets the standard. Otherwise, the performance of the cement kiln waste heat boiler does not meet the standard.

[0029] Condition 1: The boiler evaporation correction value X is greater than the boiler evaporation guarantee value;

[0030] Condition 2: Boiler exhaust gas side pressure loss correction value P 修正 Less than the guaranteed value of pressure loss on the boiler exhaust gas side.

[0031] Boiler evaporation correction

[0032] The boiler evaporation capacity is a basic performance indicator that reflects whether the waste heat boiler meets the standard, and this indicator is affected by the waste heat boiler inlet exhaust gas flow, exhaust gas temperature, drum feed water temperature, main steam pressure, main steam temperature and other parameters. The above parameters change instantaneously during operation and cannot be completely consistent with the boiler design benchmark parameters. It is necessary to adopt objective and reasonable corrections to correct the actual operating parameters to the benchmark values. The corrected boiler evaporation capacity is compared with the guaranteed evaporation capacity in the contract or technical specifications. If the corrected boiler evaporation capacity is greater than the guaranteed evaporation capacity, the boiler evaporation capacity index meets the standard. If it is less than the guaranteed evaporation capacity, the boiler evaporation capacity index does not meet the standard, and the boiler supplier needs to repair and rectify or compensate the customer for losses.

[0033] The boiler evaporation correction formula is as follows:

[0034]

[0035] X is the correction value of the boiler superheater outlet evaporation, that is, the boiler evaporation correction value, unit: [t / h]; X m is the measured value of the evaporation at the boiler superheater outlet, that is, the measured value of the boiler evaporation, unit: [t / h]; A is the evaporation deviation value, which is caused by the deviation between the actual exhaust gas volume at the boiler inlet and the reference exhaust gas volume, and the deviation between the actual exhaust gas temperature and the reference exhaust gas temperature. Based on the actual exhaust gas flow and actual exhaust gas temperature at the boiler inlet, the correction curve provided by the supplier can be checked to determine the value of A; unit: [t / h]; F w F is the boiler feed water temperature correction coefficient, which is determined based on the actual boiler feed water temperature and the correction curve provided by the supplier; p F is the boiler steam pressure correction factor, which is determined based on the actual steam pressure of the boiler and the correction curve provided by the supplier; t It is the boiler steam temperature correction factor, and its value is determined by checking the correction curve provided by the supplier based on the actual steam temperature of the boiler.

[0036] Correction of pressure loss on boiler exhaust gas side

[0037] The boiler exhaust gas side pressure loss is an important indicator of boiler performance. The size of this indicator determines the power consumption of the boiler smoke and air outlet fan. The greater the exhaust gas pressure loss, the greater the fan power consumption and the worse the performance. The size of the boiler exhaust gas side pressure loss is mainly affected by the boiler inlet air volume, inlet air temperature, outlet air volume, outlet air temperature and other parameters. When the boiler duct and boiler are determined, the greater the inlet and outlet air volume, the greater the exhaust gas side pressure loss. In the actual operation process, the actual inlet air temperature and air volume of the boiler deviate from the design reference value. How to correct the exhaust gas pressure loss of the actual operating boiler according to the inlet and outlet air volume, air temperature correction value or correction coefficient to the reference air volume and air temperature, and compare the corrected exhaust gas pressure loss with the guaranteed value in the contract or technical specification. If the corrected exhaust gas side pressure loss is less than the guaranteed value of the boiler exhaust gas side pressure loss, the boiler exhaust gas side pressure loss index meets the standard. If the corrected exhaust gas side pressure loss is about the guaranteed value, the boiler exhaust gas side pressure loss index does not meet the standard, and the boiler supplier needs to repair and rectify or compensate the customer for the loss.

[0038] P 测量 =P 入测量 +P 本测量 +P 出测量

[0039] P 测量 is the measured value of the pressure loss on the boiler exhaust side mm H 2 O

[0040] P 入测量 is the measured value of the pressure loss of the smoke and air duct at the boiler inlet (mm H) 2 O

[0041] P 出测量 is the measured value of the pressure loss of the flue gas duct at the boiler outlet mm H 2 O

[0042] P 本测量 is the measured value of boiler body pressure loss mm H 2 O

[0043] P 入测量 =(P 1 -P 2 )×1000 / 9.80665

[0044] P 本测量 =(P 3 -P 2 )×1000 / 9.80665

[0045] P 出测量 =(P 4 -P 3 )×1000 / 9.80665

[0046] P 1The static pressure measurement value at the boiler inlet air duct interface kPa

[0047] P 2 kPa is the static pressure measurement value of the boiler body inlet

[0048] P 3 kPa is the static pressure measurement value at the boiler outlet

[0049] P 4 The static pressure measurement value at the boiler outlet air duct interface kPa

[0050] P 修正 =P 入修正 +P 出修正 +P 本修正

[0051] P 修正 is the actual pressure loss correction value of the boiler system mm H 2 O

[0052] P 入修正 is the correction value of the pressure loss of the flue gas duct at the boiler inlet mm H 2 O

[0053] P 出修正 is the correction value of the pressure loss of the flue gas duct at the boiler outlet mm H 2 O

[0054] P 本修正 is the boiler body pressure loss correction value mm H 2 O

[0055] P 入修正 =P 入测量 ×(Vg 参标况入 / Vg 实标况入 ) 2 ×(273.15+T 参考入 ) / (273.15+T 实际入 )×[(P 1 +P 2 ) / 2 / P 基准入 ]

[0056] P 本修正 =P 本测量 ×(Vg 参标况本 / Vg 实标况本 ) 2 ×(273.15+T 参考本 ) / (273.15+T 实际本 )×[(P 2 +P 3 ) / 2 / P 基准本 ]

[0057] P出修正 =P 出测量 ×(Vg 参标况出 / Vg 实标况出 ) 2 ×(273.15+T 参考出 ) / (273.15+T 实际出 )×[(P 3 +P 4 ) / 2 / P 基准出 ]

[0058] Vg 参标况入 The standard air volume of the inlet duct is Nm 3 / h

[0059] Vg 实标况入 The actual standard air volume of the inlet duct Nm 3 / h

[0060] Vg 参标况出 The standard air volume of the outlet duct is Nm 3 / h

[0061] Vg 实标况出 The actual standard air volume of the outlet air duct Nm 3 / h

[0062] Vg 参标况本 The standard air volume of the boiler body Nm 3 / h

[0063] Vg 实标况本 The actual standard air volume of the boiler body Nm 3 / h

[0064] T 参考入 is the reference exhaust gas qualitative temperature of the inlet air duct ℃

[0065] T 实际入 is the actual exhaust gas qualitative temperature of the inlet duct ℃

[0066] T 参考本 The reference exhaust gas qualitative temperature of the boiler body ℃

[0067] T 实际本 is the actual exhaust gas qualitative temperature of the boiler body ℃

[0068] T 参考出 The standard exhaust gas temperature at the outlet duct is ℃

[0069] T 实际出 is the actual exhaust gas qualitative temperature of the outlet air duct ℃

[0070] P 基准入 The design basis exhaust gas pressure of the inlet air duct is kPa

[0071] P 基准本 The design reference exhaust gas pressure of the boiler body kPa

[0072] P 基准出 The design base exhaust pressure of the outlet air duct is kPa

[0073] Note: The above exhaust gas qualitative temperature is calculated based on the average of the exhaust gas temperatures at the inlet and outlet of the inlet duct, boiler body, and outlet duct. For example, two temperature detection points are set at the inlet duct, the inlet duct inlet and the outlet of the inlet duct. Assuming that the actual exhaust gas qualitative temperature at the inlet duct inlet is 350°C, and the actual exhaust gas qualitative temperature at the outlet of the inlet duct is 340°C, the actual exhaust gas qualitative temperature of the inlet duct is = (350°C + 340°C) / 2 = 345°C;

[0074] The above-mentioned benchmark standard air volume, benchmark exhaust gas qualitative temperature and benchmark exhaust gas pressure are all benchmark values ​​set during boiler design.

[0075] Calculation of boiler exhaust gas flow

[0076] Cement kiln waste heat boilers are mainly of two types: PH boilers and AQC boilers. The exhaust gas flow rate calculation will be carried out according to the following method:

[0077] 1) Exhaust gas enthalpy;

[0078] 2) Calculate steam and feed water enthalpy based on standard pressure and temperature parameters;

[0079] 3) Calculate the boiler surface heat loss based on standard temperature parameters;

[0080] 4) Calculate the exhaust gas flow rate based on the approximate data calculated.

[0081] Based on the above method, the exhaust gas flow rate of the inlet duct in the boiler evaporation correction formula, the reference standard air volume of the inlet duct in the boiler exhaust gas side pressure loss correction formula, the reference standard air volume of the outlet duct and the reference standard air volume of the boiler body, the actual standard air volume of the inlet duct, the actual standard air volume of the outlet duct and the actual standard air volume of the boiler body can be obtained.

[0082] PH boiler exhaust gas flow calculation

[0083]

[0084] Vg is the exhaust gas flow rate [Nm 3 / h]

[0085] F is the rated steam flow rate at the superheater outlet [kg / h]

[0086] Jg 1 is the heat enthalpy of the dusty exhaust gas at the boiler inlet [kcal / Nm 3 ]

[0087] Jg 2 is the heat enthalpy of the dusty exhaust gas at the boiler outlet [kcal / Nm 3 ]

[0088] h 1 is the boiler inlet feed water enthalpy [kcal / kg]

[0089] h 2 is the enthalpy of steam at boiler outlet [kcal / kg]

[0090] L is the heat loss from the boiler outer surface [kcal / h]

[0091]

[0092] K is the heat transfer coefficient (K = 4.186 × 10 kJ / m 2 h℃)

[0093] A 1 is the surface area of ​​the boiler inlet shell [m 2 ]

[0094] A 2 is the surface area of ​​the boiler shell [m 2 ]

[0095] A 3 is the boiler outlet shell surface area [m 2 ]

[0096] A 4 is the pipe surface area [m 2 ]

[0097] T 1 is the boiler inlet shell surface temperature [℃]

[0098] T 2 is the boiler shell surface temperature [℃]

[0099] T 3 is the boiler outlet shell surface temperature [℃]

[0100] T 4 is the pipe surface temperature [℃]

[0101] T 0 is the atmospheric temperature [℃]

[0102] AQC boiler exhaust gas flow calculation

[0103]

[0104] Vg is the exhaust gas flow rate [Nm 3 / h]

[0105] F is the rated steam flow rate at the superheater outlet [kg / h]

[0106] F" is the rated feed water flow rate at the economizer inlet [kg / h]

[0107] Jg 1 is the heat enthalpy of the dusty exhaust gas at the boiler inlet [kcal / Nm 3 ]

[0108] Jg 2 is the heat enthalpy of the dusty exhaust gas at the boiler outlet [kcal / Nm 3 ]

[0109] h 0 is the feed water enthalpy at the economizer inlet [kcal / kg]

[0110] h 1 is the boiler inlet feed water enthalpy [kcal / kg]

[0111] h 2 is the enthalpy of steam at boiler outlet [kcal / kg]

[0112] L is the heat loss from the boiler outer surface [kcal / h]

[0113]

[0114] K is the heat transfer coefficient (K = 4.186 × 10 kJ / m 2 h℃)

[0115] A 1 is the surface area of ​​the boiler inlet shell [m 2 ]

[0116] A 2 is the surface area of ​​the boiler shell [m 2 ]

[0117] A 3 is the boiler outlet shell surface area [m 2 ]

[0118] A 4 is the pipe surface area [m 2 ]

[0119] T 1 is the boiler inlet shell surface temperature [℃]

[0120] T 2 is the boiler shell surface temperature [℃]

[0121] T 3 is the boiler outlet shell surface temperature [℃]

[0122] T 4 is the pipe surface temperature [℃]

[0123] T 0 is the atmospheric temperature [℃]

[0124] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A cement kiln waste heat boiler performance evaluation method, characterized in that: The method specifically comprises the following steps: S1, measured value of boiler evaporation X m , boiler exhaust side pressure loss measurement value P 测量 Correction is performed to obtain the boiler evaporation correction value X and the boiler exhaust gas side pressure loss correction value P 修正 ; S2, based on the boiler evaporation correction value X and the boiler exhaust side pressure loss correction value P 修正 Evaluate the performance of the cement kiln waste heat boiler. If both conditions 1 and 2 are met, the performance of the cement kiln waste heat boiler meets the standard. Otherwise, the performance of the cement kiln waste heat boiler does not meet the standard. Condition 1: The boiler evaporation correction value X is greater than the boiler evaporation guarantee value; Condition 2: Boiler exhaust gas side pressure loss correction value P 修正 Less than the guaranteed value of pressure loss on the boiler exhaust gas side; The calculation formula of boiler evaporation correction value X is as follows: Where X is the evaporation correction value at the boiler superheater outlet, that is, the boiler evaporation correction value X; X m is the measured value of boiler superheater outlet evaporation, that is, the boiler evaporation measurement value X m ; A is the evaporation deviation value, which is caused by the deviation between the actual exhaust gas volume at the boiler inlet and the reference exhaust gas volume, and the deviation between the actual exhaust gas temperature and the reference exhaust gas temperature; F w is the boiler feed water temperature correction coefficient; F p is the boiler steam pressure correction factor; F t is the boiler steam temperature correction factor; Boiler exhaust gas side pressure loss correction value P 修正 The calculation formula is as follows: P 修正 =P 入修正 +P 出修正 +P 本修正 Among them, P 修正 P is the correction value of the pressure loss on the boiler exhaust gas side; 入修正 P is the correction value of the pressure loss of the flue gas duct at the boiler inlet; 出修正 P is the correction value of the pressure loss of the flue gas duct at the boiler outlet; 本修正 is the boiler body pressure loss correction value; P 入修正 =P 入测量 ×(Vg 参标况入 / Vg 实标况入 ) 2 ×(273.15+T 参考入 ) / (273.15+T 实 际入 )×[(P1+P2) / 2 / P 基准入 ]; P 本修正 =P 本测量 ×(Vg 参标况本 / Vg 实标况本 ) 2 ×(273.15+T 参考本 ) / (273.15+T 实际 本 )×[(P2+P3) / 2 / P 基准本 ]; P 出修正 =P 出测量 ×(Vg 参标况出 / Vg 实标况出 ) 2 ×(273.15+T 参考出 ) / (273.15+T 实际 出 )×[(P3+P4) / 2 / P 基准出 ]; Vg 参标况入 Vg is the standard air volume of the inlet duct. 实标况入 Vg is the actual standard air volume of the inlet duct, 参标况出 Vg is the standard air volume of the outlet duct. 实标况出 Vg is the actual standard air volume of the outlet duct, 参标况本 Vg is the standard air volume of the boiler body. 实标况本 is the actual standard air volume of the boiler body; T 参考入 is the reference exhaust gas qualitative temperature of the inlet duct, T 实际入 is the actual exhaust gas qualitative temperature of the inlet duct, T 参考本 is the reference exhaust gas qualitative temperature of the boiler body, T 实际本 is the actual exhaust gas qualitative temperature of the boiler body, T 参考出 is the reference exhaust gas qualitative temperature of the outlet air duct, T 实际出 is the actual exhaust gas qualitative temperature of the outlet air duct; P 基准入 is the design basis exhaust gas pressure of the inlet duct, P 基准本 is the design reference exhaust gas pressure of the boiler body, P 基准出 It is the design base exhaust gas pressure of outlet air duct.

2. The cement kiln waste heat boiler performance evaluation method according to claim 1, characterized in that: Boiler exhaust side pressure loss measurement value P 测量 The calculation formula is as follows: P 测量 =P 入测量 +P 本测量 +P 出测量 Among them, P 测量 is the measured value of the pressure loss on the boiler exhaust gas side; P 入测量 is the measured value of the pressure loss of the flue gas duct at the boiler inlet, P 入测量 =(P1-P2)×1000 / 9.80665; P 出测量 is the measured pressure loss of the flue gas duct at the boiler outlet, P 出测量 =(P4-P3)×1000 / 9.80665; P 本测量 is the measured value of boiler body pressure loss, P 本测量 =(P3-P2)×1000 / 9.80665; P1 is the static pressure measurement value of the boiler inlet air duct interface point, P2 is the static pressure measurement value of the boiler body inlet, P3 is the static pressure measurement value of the boiler body outlet, and P4 is the static pressure measurement value of the boiler outlet air duct interface point.

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