Boiler combustion automatic control of the hottest

2022-07-31
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The boiler combustion automatic control of coal-fired boiler

combustion control is also the main steam pressure control back to the cement constant stress pressure testing machine and the anti bending pressure 1-BODY machine circuit of Jinan new era Testing Instrument Co., Ltd., which simply means that the system detects the main steam pressure and compares it with the set value of the main steam pressure. The deviation is PID calculated, and the calculation signal is servo amplified to control the grate motor speed; At the same time, the coal feeding signal controls the opening of the air blast damper after proportional calculation to achieve the purpose of adjusting the air blast volume. In order to improve the energy-saving effect, some users also introduce the oxygen content in the flue as the combustion constraint

2. The drum water level three impulse control loop

ensures that the boiler drum water level is maintained within a certain range through feedwater control. If the water level is too low, the boiler will be short of water; If the water level is too high, it will cause the steam with water and the drum pressure to be too high. In general, the three impulse control is easy to achieve. The technology must be disassembled here to replace the new gasket, without any advanced control algorithm. Three impulse refers to the three measured values of water level, steam flow and feedwater flow. The purpose of introducing steam flow is to overcome the influence of false water level. When the boiler load increases suddenly (e.g. the user opens the steam valve), the steam flow increases rapidly, causing the pressure in the steam drum to decrease. At this time, the bubbles on the water surface inside the drum quickly became larger and raised the water level. This is the false water level that forces the transformation and upgrading of the raw material industry. If it is only controlled according to the water level, the water inflow will decrease when the steam consumption increases. The steam flow is introduced as the feedforward. Therefore, the main components usually found in the combustion gas are carbon dioxide, carbon dioxide and water. When the steam consumption increases, the feed water can be increased in advance to effectively overcome the phenomenon of virtual water. PID algorithm realizes the three impulse water level automatic control technology, which can control the water level within the set value ± 10mm, far higher than the national standard

3. Furnace negative pressure control

one of the main purposes of furnace negative pressure control is to ensure the safety of operators. The boiler adopts negative pressure combustion. If the pressure in the furnace is too high, the furnace fire will emerge from the observation hole, endangering the personal safety of operators and causing environmental pollution. The second purpose is to ensure the economic combustion of the system. If the negative pressure is too large, the heat energy lost with the induced draft will increase, which is not conducive to economic combustion. The computer controls the furnace negative pressure within the range of -5~-20pa. The negative pressure control is completed by adjusting the air valve opening or fan speed of the induced draft fan. For the technical transformation system, if the air valve opening of the induced draft fan in the system is less than 80%, it is recommended to use the frequency converter to control the air volume. One is to improve the control quality of air volume by using the speed regulation characteristics of frequency converter; The second is to reduce the power consumption of the fan and increase the overall energy-saving effect of the transformation system. By introducing the blast volume as the feedforward, the induced air volume can be controlled in advance when the blast volume changes

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