Energy-saving transformation method for existing boiler induced draft fan and primary fan

Abstract

The invention discloses an energy-saving transformation method for an induced draft fan and a primary fan of an existing boiler, which comprises the following steps of: 1, adding a frequency converter power distribution room in a boiler air and smoke system, respectively connecting a motor of the induced draft fan and a motor of the primary fan with an intelligent frequency converter, and connecting the intelligent frequency converter into the frequency converter power distribution room; secondly, the logic configuration of the control system is modified, the control system automatically controls the rotating speed of the motor through the intelligent frequency converter, and the air speed and the air volume are adjusted; and thirdly, production loads and rotating speed parameters of the draught fan and the primary draught fan are obtained and analyzed and processed, the operation state of the intelligent frequency converter is adjusted according to the analysis and processing result, and operation of the draught fan and the primary draught fan is stabilized. Electric energy is saved, and unmanned full-automatic operation can be achieved in combination with a control system.

Description

Technical Field

[0001] The invention relates to the technical field of energy-saving transformation of boilers, and in particular to an energy-saving transformation method for an existing boiler induced draft fan and a primary fan. Background Art

[0002] In recent years, in the newly built large-scale coal chemical enterprises in my country, the three major fans of the boiler - the forced draft fan, the induced draft fan and the primary fan (or dust exhaust fan) are one of the main auxiliary machines used in the process of large-scale coal chemical enterprises. Their power consumption accounts for about 1.5%-2.5% of the total power generation of the power plant. The safety and economy of their operation are directly related to the safe and economic operation of the generator set and even the entire enterprise. Therefore, the reliability and economy of the fan operation of the enterprise manufacturer have always been a matter of great concern to coal chemical enterprises. The number of enterprises that adopt hydraulic coupling fans for speed adjustment has gradually increased. However, since the original speed adjustment of the boiler primary fan and induced draft fan uses hydraulic coupling, the adjustment accuracy is poor and the power consumption is high. Generally, the manufacturers of forced draft fans, induced draft fans and primary fans all use dynamically adjusted axial flow fans. The annual average total power consumption rate of the three major fans (the percentage of the total power generation of the power plant) is generally above 2%, and the best is close to 2%. Compared with the advanced level abroad, there is still a gap, and the overall operation economy needs to be further improved.

[0003] The main reason for the modification of induced draft fans and primary fans is low operating efficiency and high energy consumption. In recent years, more and more manufacturers have reported problems with induced draft fans to the State Power Thermal Engineering Research Institute (hereinafter referred to as TPRI). The main problems of induced draft fans and primary fans are low operating efficiency, high energy consumption, and the wear problem is still prominent. After analysis, the main reasons for the low operating efficiency and high energy consumption of induced draft fans and primary fans are: first, improper selection; second, the actual performance of the fan does not reach the design value; third, the hydraulic coupling speed regulation efficiency is low, and its efficiency is proportional to the speed ratio. The lower the speed of the load, the lower its efficiency and the higher its loss.

[0004] In summary, there is an urgent need to develop a method for energy-saving transformation to further improve the economic performance of the boiler system and better achieve efficient and stable operation of the boiler system. Summary of the invention

[0005] The current problem is that coal chemical enterprises mostly use hydraulic couplings in their boiler systems, which have poor regulation accuracy and high power consumption.

[0006] In order to solve the above technical problems, the present application provides an energy-saving transformation method for an existing boiler induced draft fan and a primary fan, wherein the boiler air and smoke system includes a blower, a primary fan, an induced draft fan, a duct connection pipe, a furnace, a flue, an air preheater, a dust collector, a chimney and other equipment, the furnace outlet is connected to the air preheater; a dust collector group is installed at the outlet of each air preheater; each group of dust collectors is connected to an induced draft fan; the induced draft fan outlet is connected to the chimney through the flue; the blower is installed at the air inlet of the air preheater; the primary fan is connected to the air inlet of the air preheater; the control host is connected to the primary fan and the induced draft fan respectively; the control system is connected to the control host, and the energy-saving transformation of the induced draft fan and the primary fan includes the following steps:

[0007] Step 1: Add a frequency converter power distribution room in the boiler air and smoke system. The motors of the induced draft fan and primary fan are connected to an intelligent frequency converter respectively, and the intelligent frequency converter is connected to the frequency converter power distribution room;

[0008] Step 2: Modify the logic configuration of the control system. The control system automatically controls the speed of the motor through the intelligent inverter to adjust the wind speed and air volume;

[0009] Step 3: Obtain the production load and speed parameters of the fan and primary fan, analyze and process them, adjust the operating status of the intelligent inverter according to the analysis and processing results, and stabilize the operation of the fan and primary fan.

[0010] According to an embodiment of the present application, based on step two, the intelligent frequency converter controls the rotation speed of the motor to adjust the fan speed, and the rotation speeds of the fan and the primary fan are consistent with the rotation speeds of the motors to which they are respectively connected.

[0011] According to the embodiment of the present application, based on step three, the programmable controller of the control system performs processing and analysis, calculates the air volume value required for the production load through the built-in control algorithm analysis, and outputs a control quantity signal to adjust the speed of the fan to prevent the loss of the boiler induced draft fan and the primary fan.

[0012] According to an embodiment of the present application, a programmable controller includes a CPU, a high-speed counting module, an A / D module, a D / A module, an I / O module and a wireless communication module.

[0013] According to an embodiment of the present application, the wireless communication module adopts one or more of fiber optic Ethernet ring network, NB-IOT, 4G, WIFI, and Bluetooth transmission.

[0014] According to an embodiment of the present application, the intelligent inverter is connected to a control host.

[0015] According to an embodiment of the present application, the control system is a DCS control system or a PLC control system.

[0016] According to an embodiment of the present application, the induced draft fan has an electricity load of 483 kwh per hour.

[0017] According to an embodiment of the present application, the primary fan has an hourly power load of 273 kwh.

[0018] According to the embodiment of the present application, an intelligent frequency converter is used for adjustment, and the speed adjustment frequency control accuracy of the primary fan and the induced draft fan is 0.01HZ.

[0019] The beneficial effects of the technical solution of the present invention compared with the prior art are:

[0020] 1. This application can reduce energy consumption and noise by automatically optimizing energy consumption and modulation frequency; the intelligent frequency converter controls the frequency conversion of boiler induced draft fans and primary fan motors, reduces the impact of motor startup on the power grid, reduces the vibration and noise of boiler induced draft fans and primary fans, and extends the service life of the equipment. Through simple parameter settings, the control system automatically optimizes the motor energy consumption and makes the motor run at maximum efficiency. This application adopts variable frequency speed regulation, without slip loss, which can save the loss of hydraulic couplings of induced draft fans and primary fans.

[0021] 2. The present invention saves electric energy and can realize unmanned fully automatic operation in combination with DCS and PLC; one-key start and stop operation can be realized based on the wireless transmission function; the present invention has a high degree of application integration, small footprint and low investment.

[0022] 3. In practical applications, the present invention reduces the hourly power load of boiler induced draft fan from 586kwh to 483kwh, saving 103kwh; the hourly power load of boiler primary fan is reduced from 437kwh to 273kwh, saving 164kwh. In general, the present invention saves 267kw / h of electricity, saves 2.34 million kwh of electricity per year, reduces carbon emissions by 1,353 tons, and creates benefits of 1.68 million yuan. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The figure is a functional block diagram of an example device of the present invention. Specific implementation method:

[0024] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] The air supply method of the boiler induced draft fan is related to the position of the fuel relative to the combustion chamber. The boiler induced draft fan sends air from the air port into the boiler fuel combustion area through the wind wheel, which promotes the combustion process and takes away a large amount of exhaust gas to ensure the normal combustion of the boiler. The primary fan introduces compressed air from the outside of the boiler into the boiler burner, fully mixes it with the fuel, and achieves efficient combustion. There are many ways to install the primary fan. Some are installed directly through the exhaust duct and directly connected to the burner, and some are sent to the boiler after pressure is divided by the air handling equipment.

[0026] See also Figure 1 As shown, a method for energy-saving transformation of an existing boiler induced draft fan and a primary fan is shown, comprising the following steps:

[0027] Step 1: Add a frequency converter power distribution room in the boiler air and smoke system. The motors of the induced draft fan and primary fan are connected to an intelligent frequency converter respectively, and the intelligent frequency converter is connected to the frequency converter power distribution room;

[0028] Step 2: Modify the logic configuration of the control system. The control system automatically controls the speed of the motor through the intelligent inverter to adjust the wind speed and air volume;

[0029] Step 3: Obtain the production load and speed parameters of the fan and primary fan, analyze and process them, adjust the operating status of the intelligent inverter according to the analysis and processing results, and stabilize the operation of the fan and primary fan.

[0030] It can be understood that in this embodiment, the boiler air and smoke system includes a blower, a primary blower, an induced draft fan, a duct connection pipe, a furnace, a flue, an air preheater, a dust collector, a chimney and other equipment. The furnace outlet is connected to the air preheater; a dust collector group is installed at the outlet of each air preheater; each group of dust collectors is connected to an induced draft fan; the induced draft fan outlet is connected to the chimney through the flue; the blower is installed at the air inlet of the air preheater; the primary blower is connected to the air inlet of the air preheater; the control host is connected to the primary blower and the induced draft fan respectively; the control system is connected to the control host. The current boiler air and smoke system is designed that after the dust collector, the flue is connected and converged as a whole, and then enters the induced draft fan in two ways. The induced draft fan adopts a parallel operation mode, and the flue gas is sent to the desulfurization system after the blower works.

[0031] Furthermore, based on step two, the intelligent frequency converter controls the rotation speed of the motor to adjust the fan speed, and the rotation speeds of the fan and the primary fan are consistent with the rotation speeds of the motors to which they are respectively connected.

[0032] Furthermore, based on step three, the programmable controller of the control system performs processing and analysis, calculates the air volume value required for the production load through the built-in control algorithm analysis, and outputs a control quantity signal to adjust the fan speed to prevent the loss of the boiler induced draft fan and the primary fan.

[0033] Furthermore, the programmable controller includes a CPU, a high-speed counting module, an A / D module, a D / A module, an I / O module and a wireless communication module. The wireless communication module adopts one or more of optical fiber Ethernet ring network, NB-IOT, 4G, WIFI, and Bluetooth transmission.

[0034] Furthermore, the intelligent frequency converter is connected to the control host, and the control host is also connected to the air preheater, the blower, the primary blower, the induced draft fan and other equipment power distribution online monitoring systems.

[0035] Furthermore, the control system can be a DCS control system or a PLC control system. The control system can complete the automatic control task of the fan negative pressure and speed by writing a program, setting the corresponding proportional, integral, and differential parameters in the software, and outputting the current signal to the intelligent frequency converter.

[0036] Furthermore, the induced draft fan has an hourly power load of 483 kwh, and the primary fan has an hourly power load of 273 kwh.

[0037] Furthermore, intelligent frequency converter is used for adjustment, and the speed adjustment frequency of primary fan and induced draft fan has a control accuracy of 0.01HZ.

[0038] In the embodiment of the present invention, taking two 130t / h boilers producing high-pressure steam as an example, the above-mentioned energy-saving transformation method of an existing boiler induced draft fan and a primary fan is adopted, and the hourly power load of the boiler induced draft fan is reduced from 586kwh to 483kwh, saving 103kwh; the hourly power load of the boiler primary fan is reduced from 437kwh to 273kwh, saving 164kwh. In summary, the present invention saves 267kw / h of electricity, saves 2.34 million kWh of electricity per year, reduces carbon emissions by 1,353 tons, and creates benefits of 1.68 million yuan.

[0039] In summary, the technical solution of this application has the following beneficial effects:

[0040] 1. This application can reduce energy consumption and noise by automatically optimizing energy consumption and modulation frequency; the intelligent frequency converter controls the frequency conversion of boiler induced draft fans and primary fan motors, reduces the impact of motor startup on the power grid, reduces the vibration and noise of boiler induced draft fans and primary fans, and extends the service life of the equipment. Through simple parameter settings, the control system automatically optimizes the motor energy consumption and makes the motor run at maximum efficiency. This application adopts variable frequency speed regulation, without slip loss, which can save the loss of hydraulic couplings of induced draft fans and primary fans.

[0041] 2. The present invention saves electric energy and can realize unmanned fully automatic operation in combination with DCS and PLC; one-key start and stop operation can be realized based on the wireless transmission function; the present invention has a high degree of application integration, small footprint and low investment.

[0042] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for energy-saving transformation of existing boiler induced draft fans and primary fans, characterized in that: The boiler air and smoke system includes a blower, a primary blower, an induced draft fan, a duct connection pipe, a furnace, a flue, an air preheater, a dust collector, a chimney and other equipment. The furnace outlet is connected to the air preheater; a dust collector group is installed at the outlet of each air preheater; each group of dust collectors is connected to an induced draft fan; the outlet of the induced draft fan is connected to the chimney through the flue; the blower is installed at the air inlet of the air preheater; the primary blower is connected to the air inlet of the air preheater; the control host is connected to the primary blower and the induced draft fan respectively; the control system is connected to the control host, and the energy-saving transformation of the induced draft fan and the primary blower includes the following steps: Step 1: Add a frequency converter power distribution room to the boiler air and smoke system, the motors of the induced draft fan and the primary fan are respectively connected to an intelligent frequency converter, and the intelligent frequency converter is connected to the frequency converter power distribution room; Step 2: modifying the logic configuration of the control system, wherein the control system automatically controls the speed of the motor through the intelligent inverter to adjust the wind speed and air volume; Step three: Obtain the production load and speed parameters of the fan and the primary fan, perform analysis and processing, adjust the operating state of the intelligent inverter according to the analysis and processing results, and stabilize the operation of the fan and the primary fan.

2. The energy-saving transformation method of an existing boiler induced draft fan and primary fan according to claim 1 is characterized in that: Based on step 2, the intelligent frequency converter controls the rotation speed of the motor to adjust the fan speed, and the rotation speeds of the fan and the primary fan are consistent with the rotation speeds of the motors to which they are respectively connected.

3. The energy-saving transformation method of an existing boiler induced draft fan and primary fan according to claim 1 is characterized in that: Based on step three, the programmable controller of the control system performs processing and analysis, calculates the air volume value required for the production load through the built-in control algorithm analysis, and outputs a control quantity signal to adjust the speed of the fan to prevent the loss of the boiler induced draft fan and the primary fan.

4. The energy-saving transformation method of an existing boiler induced draft fan and primary fan according to claim 3 is characterized in that: The programmable controller comprises a CPU, a high-speed counting module, an A / D module, a D / A module, an I / O module and a wireless communication module.

5. The energy-saving transformation method of an existing boiler induced draft fan and primary fan according to claim 4 is characterized in that: The wireless communication module adopts one or more of optical fiber Ethernet ring network, NB-IOT, 4G, WIFI, and Bluetooth transmission.

6. The energy-saving transformation method of an existing boiler induced draft fan and primary fan according to claim 1, characterized in that: The intelligent frequency converter is connected to the control host.

7. The energy-saving transformation method of an existing boiler induced draft fan and primary fan according to claim 1 is characterized in that: The control system is a DCS control system or a PLC control system.

8. The energy-saving transformation method of an existing boiler induced draft fan and primary fan according to claim 1 is characterized in that: The induced draft fan has an electricity load of 483 kwh per hour.

9. The energy-saving transformation method of an existing boiler induced draft fan and primary fan according to claim 1, characterized in that: The primary fan has an hourly power load of 273 kwh.

10. The energy-saving transformation method of an existing boiler induced draft fan and primary fan according to claim 1, characterized in that: By adopting the intelligent frequency converter for adjustment, the speed adjustment frequency control accuracy of the primary fan and induced draft fan is 0.01HZ.

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