Device and method for controlling the fuel-air ratio during the combustion of ground coal in the firing system of a coal power plant

Abstract

The invention relates to a device and method for controlling the fuel-air ratio during the combustion of ground coal in the firing system of a coal power plant, which comprises means for the pneumatic delivery of ground coal to the burners of the firing system of the coal power plant and means for feeding combustion air to the burners or into the firing chamber of the firing system of the coal power plant and in which the amount of combustion air and the amount of carrier air is controlled. The aim of the invention is to achieve a high reliability of the control combined with low maintenance of the air mass measurement devices for measuring the amount of combustion air and carrier air. According to the invention, this aim is achieved by a measurement device for measuring the amount of combustion air which, according to the correlation measurement method, evaluates the triboelectric effects on sensors which are arranged in series in the direction of flow of the combustion air and thus measures the flow velocity of the combustion air. To this end, between 0.1 mg and 10 mg of fine-grained particles having a particle diameter of between 20 mirometers and 200 micrometers are introducedper m3 air into the suctioned fresh air. The introduction of particles into the suctioned fresh air is carried out essentially during the starting phase of a firing system of a coal power plant. The measurement of the amount of carrier air is preferably carried out by means of a correlation measurement device that evaluates the triboelectric effects on sensors which are arranged in series in the carrier air stream in the direction of flow of the carrier air.

Description

technical field [0001] The present invention relates to an apparatus for controlling the fuel-air ratio during the combustion of ground coal in a combustion system of a coal-fired power station, comprising: means for pneumatically conveying the ground coal to the combustion furnace of a coal-fired power station, and A device for providing combustion-supporting air in the combustion furnace or combustion chamber of the combustion system of a power station, wherein at least the following equipment is arranged along the direction of air flow: a fresh air blower for absorbing fresh air from the atmosphere; a part of the inhaled fresh air Fan coal mills for delivery of carrier air carrying pulverized coal; regenerative air preheaters for preheating intake fresh air and a portion of carrier air by using exhaust heat from the combustion system of coal-fired power stations, Among them, the storage block of the regenerative air preheater is alternately heated by the hot exhaust gas and...

AI Technical Summary

Problems solved by technology

The problem is that the degree of contamination of the pressure sensor cannot be determined solely from the measured pressure difference, so there is a huge possibility of large errors in the measurement results in the case of continuous operation

This will cause a bias in the air volume measurement which is difficult to detect

Ultimately, this leads to inaccurate control of the fuel-air ratio, with attendant loss of efficiency and increased emissions of pollutants

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