Coal mill outlet temperature control system and method based on CO monitoring

Abstract

The invention discloses a coal mill outlet temperature control system and method based on CO monitoring. The coal mill outlet temperature control system comprises a signal processor and a controller.The signal processor receives CO concentration signals measured by the CO measuring device, a coal mill outlet temperature set value is obtained through calculation according to CO concentration and coal quality, the controller controls the opening degrees of a coal mill hot air adjusting door and a coal mill cold air adjusting door, the ratio of hot primary air volume to cold primary air volume is changed, the coal mill outlet temperature is adjusted, the coal mill outlet temperature measured by a coal mill outlet temperature measuring device is used as a feedback signal, closed-loop controlover the coal mill outlet temperature is achieved, and the purpose of optimizing and adjusting the coal mill outlet temperature is achieved. According to the system, accurate control over the coal mill outlet temperature is achieved by introducing the CO concentration signals, on the premise that the safety of a coal pulverizing system is guaranteed, the coal mill outlet temperature is increased,the cold air mixing amount of the coal pulverizing system is reduced, the smoke exhaust temperature is reduced, the boiler efficiency is improved, and safe and economical operation of a unit is facilitated.

Description

【Technical field】 [0001] The invention belongs to the energy-saving technical field of pulverizing systems in coal-fired power plants, and relates to a coal mill outlet temperature control system and method based on CO monitoring. 【Background technique】 [0002] The outlet temperature of the coal mill is the main parameter reflecting the drying output of the coal mill. The temperature of the outlet of the coal mill is an important safety indicator to prevent the spontaneous combustion of coal powder and the explosion of the gas-powder mixture, and it is also an important indicator of the economy of the pulverization system. Increase the outlet temperature of the coal mill, increase the amount of hot air in the primary air, increase the flue gas-air exchange heat of the air preheater, reduce the heat loss of the exhaust gas, increase the initial temperature of the pulverized coal airflow, and the required time for the pulverized coal to ignite The lower the heat of ignition, ...

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Problems solved by technology

[0003] At present, coal-fired power plants control the outlet temperature of coal mills mainly according to the requirements of DL / T5145-2012 "Technical Regulations for Design and Calculation of Coal Milling System in Thermal Power Plants". For control, most power plants are conservative in controlling the outlet temperature of the coal mill, which leads to an increase in the amount of cold air mixed in the pulverizing system, a decrease in the amount of cold air passing through the air preheater, an increase in the exhaust gas temperature, and a decrease in boiler efficiency

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