Control method for preventing parallel running fans from tacking phenomenon

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...

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

Images