Control method for preventing parallel running fans from tacking phenomenon

A control method and fan technology, applied in pump control, separation method, machine/engine, etc., can solve problems that endanger the operation safety of boiler units, endanger the safety of fan equipment, and the life of fan blades, and achieve a smooth switching process

Inactive Publication Date: 2017-06-20
SHANGHAI LONGKING ENVIRONMENTAL PROTECTION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Since many power plants have already been built, the new desulfurization device is often limited by the site, and the desulfurization fan can only be considered in a given limited area. For the parallel operation of two desulfurization fans, the inlet and outlet flue It is difficult to achieve a symmetrical arrangement, so although the flue gas deflector is set in the flue during design to change the flue resistance, when the flue gas volume load changes from the design working condition, the inlet and / or outlet smoke of the two fans will There will be different changes in the duct resistance, which will change the working point of the fans, causing the flue resistance of one fan to be smaller than that of the other fan, and the fan with small resistance will pass through more flue gas at this time. If measures are taken, this phenomenon will gradually intensify, more and more flue gas will pass through the fan with low resistance, and eventually the fan with high resistance will not work normally, forming the so-called "wind grabbing" phenomenon, which will endanger the fan equipment on the one hand On the other hand, it will endanger the safety of the entire desulfurization system and the operation safety of the boiler unit

Method used

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  • Control method for preventing parallel running fans from tacking phenomenon

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Example 1 - Parallel operation of two fans

[0041] When two fans, fan A and fan B, are running at the same time, the positions of gain switcher 3 and switcher 8 are as follows: figure 1 As shown, that is, the gain signal value output by the gain switcher 3 is adjustable within the range of 0.6 to 0.75, the preferred gain signal value output by the gain switcher 3 is 0.7, the output of the switcher 8 is the output of the second multiplier 11, and the output of the second multiplier 11 is The output value of the double multiplier 11 represents the difference between the output signals of the two fan outlet and inlet differential pressure transmitters 21 and 23 and is corrected by the conversion coefficient output by the coefficient setter 12 to the corresponding baffle opening correction value. The output values ​​of the gain switcher 3 and the switcher 8 enter the speed limiter 4 and the two-way speed limiter 7 respectively to ensure the smooth progress of the switching...

Embodiment 2

[0045] Example 2 - Operating conditions of a single fan

[0046] When a single fan in fan A or fan B is running, the gain switcher 3 and switcher 8 switch to the same figure 1 The opposite position, that is, the gain signal value of the gain switcher 3 output is 1, the output of the switcher 8 is 0, the gain signal value of the speed limiter 4 output after entering the steady state is 1, and the output value of the two-way speed limiter 7 is 0. At this time, the furnace negative pressure adjustment instruction is calculated by the main regulator 1 and then output the adjustment signal value to the first multiplier 2, and multiplied by the gain signal value output by the speed limiter 4 in the first multiplier 2, and the result remains unchanged, the gain adjustment value output by the first multiplier 2 is simultaneously sent to the adder A 5 and the adder B 6 . Since the two-way speed limiter 7 does not receive the output value of the second multiplier 11 at this moment, it...

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Abstract

The invention relates to a control method for preventing parallel running fans from tacking phenomenon. The method comprises the following steps: adopting a pressure difference transmitter for measuring pressure difference at outlet and inlet of each fan; performing subtraction on the measured pressure difference signal values of the two fans; applying an operation result to a regulation control loop for an opening degree of a baffle of each fan; and under the conditions that no correction function is executed when a single fan runs and each pressure difference signal and the smoke volume passing by each fan are in direct proportion to each other when the two fans run, correcting the regulation control loop for the opening degree of the baffle of the fan by the operation result of the pressure difference signal subtraction according to different directions and strengths, maintaining the equal smoke volume passing by each fan as far as possible and balancing the fan running, and meanwhile, receiving a boiler furnace negative pressure regulation instruction by the regulation control loop for the opening degree of the baffle of the fan, thereby synchronously acting according to the boiler furnace negative pressure regulation instruction and reducing the influence on the running safety of the boiler.

Description

technical field [0001] The present invention relates to the technical field of thermal control, and in particular to a control method for avoiding wind grabbing of fans running in parallel, specifically to the desulfurization fans running in parallel in the limestone (or lime) wet sulfur dioxide removal process Control Method. Background technique [0002] Limestone (or lime, the same below) wet desulfurization technology is currently widely used in the flue gas treatment system of coal-fired boilers to remove the environmentally harmful component SO in the flue gas 2 . In this technology, the flue gas discharged from the coal-fired boiler is guided to the middle of the desulfurization tower through the desulfurization fan, and then flows upward after entering the desulfurization tower, and meets and scrubs with the limestone slurry that falls from the nozzle arranged on the upper part of the desulfurization tower. , SO in flue gas 2 Chemically react with limestone to fin...

Claims

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Application Information

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IPC IPC(8): B01D53/80B01D53/50F04D27/00F04D25/16
Inventor 陈天光
Owner SHANGHAI LONGKING ENVIRONMENTAL PROTECTION
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