A double closed loop energy-saving optimization control method applied to an electric dust removal system

Abstract

The application provides a double closed loop energy-saving optimization control method applied to an electric dust removal system, according to feedback information of output flue gas turbidity of the electric dust removal system, corresponding adjustment of average secondary current is carried out, an outer ring closed loop control of the electric dust removal system is formed, so that current working power meets the requirement of outlet flue gas turbidity control index; and an optimized duty cycle is used to make the spark number not greater than a constraint upper limit value, an inner ring closed loop control of the electric dust removal system is formed, so as to maintain the working power in the outer ring closed loop control. The application adopts a comprehensive index optimization control strategy combining spark control and intermittent power supply mode, which can not only avoid the safety risk of equipment, but also achieve the best energy-saving effect.

Description

Technical Field

[0001] This invention belongs to the field of dust removal control technology, specifically a dual-closed-loop energy optimization control method applied to electrostatic precipitators. Background Technology

[0002] Currently, most domestic electrostatic precipitator systems adopt an intermittent power supply mode, which has a certain energy-saving effect due to the setting and control of the secondary current for the output dust turbidity. However, changes in the amount of dust in the flue gas directly affect the number of sparks, and in severe cases, can even lead to flashover. Therefore, although the system has an intermittent power supply mode, it is usually not used in unattended situations due to equipment safety risks.

[0003] In the control methods of electrostatic precipitator (ESP) systems, selecting a single-indicator control method with the output flue gas dust turbidity as the control target, such as adjusting the secondary current in real time based on the outlet flue gas turbidity, can meet the outlet flue gas turbidity control target, but it cannot achieve effective energy-saving operation of the ESP system. This is because the ESP process is a complex system with multi-variable coupling and significant time lag characteristics. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a dual-closed-loop energy optimization control method for electrostatic precipitators. It adopts a comprehensive index optimization control strategy that combines spark control with intermittent power supply mode, which can eliminate equipment safety risks and achieve the best energy-saving effect.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows:

[0006] A dual-closed-loop energy optimization control method for electrostatic precipitators (ESPs) involves adjusting the average secondary current based on feedback information about the turbidity of the output flue gas from the ESP to form the outer closed-loop control of the ESP, ensuring that the current operating power meets the turbidity control requirements of the outlet flue gas. The method also optimizes the duty cycle to ensure that the number of sparks does not exceed the upper limit of the constraint, forming the inner closed-loop control of the ESP to maintain the operating power in the outer closed-loop control.

[0007] As a further embodiment of the present invention, the outer loop closed-loop control specifically comprises:

[0008] Based on the current turbidity of the flue gas at the outlet of the electrostatic precipitator system, determine the set value of the average secondary current:

[0009] I 2-setup =F1(Δρ)

[0010] Δρ=ρ aim -ρ

[0011] Where F1() is the average secondary current setting model based on flue gas turbidity deviation; Δρ is the flue gas turbidity deviation; ρ aim ρ represents the target turbidity of the flue gas currently emitted by the electrostatic precipitator system; ρ represents the detected turbidity of the emitted flue gas.

[0012] At this time, the operating power of the electrostatic precipitator system is W = UI 2-setup =I 2-setup 2 R.

[0013] As a further embodiment of the present invention, the inner loop closed-loop control specifically refers to:

[0014] To maintain the operating power W, based on the currently set average secondary current I 2-setup Based on the spark detection information, determine the set value of the duty cycle within the given intermittent power supply mode pulse period T:

[0015] γ setup =F2(Δn)

[0016] Δn=n max -n,Δn>=0

[0017] In the formula, F2() is the duty cycle setting model based on the spark count constraint; n max is the upper limit of the spark count constraint; n is the current number of sparks detected.

[0018] As a further embodiment of the present invention, if Δρ>0, or ρ aim If the turbidity ρ of the emitted flue gas is greater than ρ, then the turbidity ρ of the emitted flue gas does not meet the standard. In this case, according to the dust removal efficiency formula, the corona current should be increased, that is, the average secondary current I should be increased. 2-setup So that Δρ=ρ aim –ρ=0.

[0019] As a further embodiment of the present invention, the dust removal efficiency formula is specifically as follows:

[0020] η=(1-ρ / ρ i 100%

[0021] or

[0022] η = 1 - exp(-Aω / Q)

[0023] ω=qE / 6πaμ

[0024] Where, ρ i Where A is the inlet flue gas turbidity, Q is the dust collecting electrode area, ω is the flue gas flow rate, q is the dust ingress velocity, and q is the dust charge, along with the corona current and the maximum average electric field strength E. p Peak operating voltage U p Average operating voltage U avIt is directly proportional to E; E is the electric field strength for dust collection, and is proportional to the average field strength E. av Average operating voltage U av Proportional; a is the particle radius; μ is the gas viscosity.

[0025] As a further embodiment of the present invention, the intermittent power supply mode process is as follows:

[0026] Let the pulse period of the intermittent power supply mode be T, and the duty cycle be γ = Δt / T, where Δt is the on-time within T; to maintain the minimum operating power, i.e.

[0027] W min =UI 2min =I 2min 2 R

[0028] When the charge within a pulse is determined, then we have

[0029] Δq=I2Δt=I 2min Δt max

[0030] Right now

[0031] γ max =Δt max / T

[0032] Then, under spark constraint conditions, the minimum average secondary current I 2min Or the average secondary current setpoint I 2-setup :

[0033] I 2min =I 2-setup =Δq / γ max T

[0034] stn=n max , or Δn = 0

[0035] Where, n max Here, n represents the upper limit of the spark constraint, and n is the current number of detected sparks; the current average secondary current setpoint I... 2-setup The corresponding maximum duty cycle γ of the constraint is adjusted through spark number feedback. max That is, the set value γ setup .

[0036] The beneficial effects of this invention are:

[0037] Based on feedback information regarding the turbidity of the output flue gas from the electrostatic precipitator (ESP), the average secondary current is adjusted accordingly to form the outer closed-loop control of the ESP system. This ensures that the operating power at this point meets environmental protection requirements for the dust content in the outlet flue gas. To maximize the dust removal effect and meet the operating power requirements of the outer closed-loop control, the duty cycle is optimized to ensure that the spark count does not exceed the constraint limit, thus forming the inner optimized control of the ESP system. Utilizing existing spark detection capabilities, the duty cycle of intermittent power supply is minimized to the maximum extent possible, provided that the spark count is less than or equal to the constraint limit. This achieves the target dust removal effect that meets environmental protection standards at the current operating power. By constraining the spark count, the advantages of the intermittent power supply mode are fully utilized while ensuring equipment safety. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the invention. Detailed Implementation

[0039] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] Example 1

[0042] A dual-closed-loop energy optimization control method applied to electrostatic precipitator systems includes:

[0043] 1. External links can be controlled:

[0044] Based on the current turbidity of the flue gas at the outlet of the electrostatic precipitator system, determine the set value of the average secondary current:

[0045] I 2-setup =F1(Δρ)

[0046] Δρ=ρ aim -ρ

[0047] Where F1() is the average secondary current setting model based on flue gas turbidity deviation; Δρ is the flue gas turbidity deviation; ρ aim ρ represents the target turbidity of the flue gas currently emitted by the electrostatic precipitator system; ρ represents the detected turbidity of the emitted flue gas.

[0048] At this time, the operating power of the electrostatic precipitator system is W = UI 2-setup =I 2-setup 2 R.

[0049] Emission flue gas turbidity ρ, inlet flue gas turbidity ρ i The dust removal efficiency is:

[0050] η=(1-ρ / ρ i 100%

[0051] or

[0052] η = 1 - exp(-Aω / Q)

[0053] ω=qE / 6πaμ

[0054] Where A is the area of ​​the collecting electrode, Q is the flue gas flow rate, ω is the dust ingress velocity, q is the dust charge, and is related to the corona current and the maximum average electric field strength E. p Peak operating voltage U p Average operating voltage U av It is directly proportional to E; E is the electric field strength for dust collection, and is proportional to the average field strength E. av Average operating voltage U av Proportional; a is the particle radius; μ is the gas viscosity.

[0055] Therefore, if the turbidity ρ of the emitted flue gas does not meet the standard, i.e., Δρ>0, or ρ aim If ρ > 1, then according to the dust removal efficiency formula above, the corona current should be increased, that is, the average secondary current I should be increased. 2-setup So that Δρ=ρ aim –ρ=0. That is:

[0056] η=(1-ρ aim / ρ i 100%.

[0057] 2. Inner-loop optimization control:

[0058] To maintain operating power W, maximize dust removal efficiency, and ensure equipment safety, based on the currently set average secondary current I... 2-setup Based on the spark detection information, determine the set value of the duty cycle within the given intermittent power supply mode pulse period T:

[0059] γ setup =F2(Δn)

[0060] Δn=n max -n,Δn>=0

[0061] In the formula, F2() is the duty cycle setting model based on the spark count constraint; n max is the upper limit of the spark count constraint; n is the current number of sparks detected.

[0062] The intermittent power supply mode process is as follows:

[0063] Let the pulse period of the intermittent power supply mode be T, and the duty cycle be γ = Δt / T, where Δt is the on-time within T; to maintain the minimum operating power, i.e.

[0064] W min =UI 2min =I 2min 2 R

[0065] When the charge within a pulse is determined, then we have

[0066] Δq=I2Δt=I 2min Δt max

[0067] Right now

[0068] γ max =Δt max / T

[0069] Therefore, the minimum average secondary current I under spark confinement conditions 2min Or the average secondary current setpoint I 2-setup :

[0070] I 2min =I 2-setup =Δq / γ max T

[0071] stn=n max , or Δn = 0

[0072] Where, n max Here, n represents the upper limit of the spark constraint, and n is the current number of detected sparks; the current average secondary current setpoint I... 2-setup The corresponding maximum duty cycle γ of the constraint is adjusted through spark number feedback. max That is, the set value γ setup .

[0073] The double-closed loop completed by steps 1 and 2 above can optimize control.

[0074] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A dual-closed-loop energy optimization control method applied to an electrostatic precipitator system, characterized in that, Based on the feedback information of the turbidity of the flue gas output by the electrostatic precipitator system, the average secondary current is adjusted accordingly to form the outer closed-loop control of the electrostatic precipitator system, so that the current working power meets the requirements of the outlet flue gas turbidity control index; the duty cycle is optimized to ensure that the number of sparks does not exceed the upper limit of the constraint, thus forming the inner closed-loop control of the electrostatic precipitator system to maintain the working power in the outer closed-loop control. The outer loop closed-loop control specifically refers to: Based on the current turbidity of the flue gas at the outlet of the electrostatic precipitator system, determine the set value of the average secondary current: I 2-setup =F1(Dr) Dr=r aim -r Where F1() is the average secondary current setting model based on flue gas turbidity deviation; Δρ is the flue gas turbidity deviation; ρ aim ρ represents the target turbidity of the flue gas currently emitted by the electrostatic precipitator system; ρ represents the detected turbidity of the emitted flue gas. At this time, the operating power of the electrostatic precipitator system is W = UI 2-setup =I 2-setup 2 R; The inner loop closed-loop control is specifically as follows: To maintain the operating power W, based on the currently set average secondary current I 2-setup Based on the spark detection information, determine the set value of the duty cycle within a given intermittent power supply mode period T: γ setup =F2(Δn) Δn=n max -n,Δn>=0 In the formula, F2() is the duty cycle setting model based on the spark count constraint; n max This represents the upper limit of the spark count constraint; n is the current number of sparks detected. The intermittent power supply mode process is as follows: Let the pulse period of the intermittent power supply mode be T, and the duty cycle be γ = Δt / T, where Δt is the on-time within T; to maintain the minimum operating power, i.e. W min =UI 2min =I 2min 2 R When the charge within a pulse is determined, then we have Δq=I2Δt=I 2min Δt max Right now c max =Δt max / T Then, under spark constraint conditions, the minimum average secondary current I 2min Or the average secondary current setpoint I 2-setup : I 2min =I 2-setup =Δq / γ max T stn=n max , or Δn = 0 Where, n max Here, n represents the upper limit of the spark constraint, and n is the current number of detected sparks; the current average secondary current setpoint I... 2-setup The corresponding maximum duty cycle γ of the constraint is adjusted through spark number feedback. max That is, the set value γ setup .

2. The method for optimizing the control of a double closed loop applied to an electrostatic precipitator system according to claim 1, characterized in that, If Δρ>0, or ρ aim If the turbidity ρ of the emitted flue gas is greater than ρ, then the turbidity ρ of the emitted flue gas does not meet the standard. In this case, according to the dust removal efficiency formula, the corona current should be increased, that is, the average secondary current I should be increased. 2-setup So that Δρ=ρ aim –ρ=0.

3. The method for optimizing the control of a double closed loop applied to an electrostatic precipitator system according to claim 2, characterized in that, The dust removal efficiency formula is as follows: n=(1-r / r) i )100% or η = 1 - exp(-Aω / Q) ω=qE / 6πaμ Where, ρ i Where A is the inlet flue gas turbidity, Q is the dust collecting electrode area, ω is the flue gas flow rate, q is the dust ingress velocity, and q is the dust charge, along with the corona current and the maximum average electric field strength E. p Peak operating voltage U p Average operating voltage U av It is directly proportional to E; E is the electric field strength for dust collection, and is proportional to the average field strength E. av Average operating voltage U av Proportional; a is the particle radius; μ is the gas viscosity.

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