Automated system for control and monitoring of explosion safety of the coal grinding process in ball drum mills

Abstract

The article presents the results of research on automated systems of control and monitoring of explosion safety of dust and gas mixture during coal grinding in ball drum mills (BDM). The problem of the gas-dynamic factor, which arises at the disintegration of coals of middle stage of metamorphism (gas coals) in the atmosphere of closed or limited space, for example in mine workings, chambers, furnace furnaces, etc., is considered. Earlier, when burning anthracite coals, such a problem did not arise, since anthracite does not have a gas component of hydrocarbons. Therefore, all automated control systems were developed from the condition of grinding quality and optimal loading of the BDM. The work aims to develop an automated system of control and monitoring of explosion safety of coal-gas mixture in ball drum mills in the process of grinding gas coals in preparation for combustion. It is established that the sizes of coal grinding fractions in the BDMs from 50 microns to 250 microns correspond to the sizes of supermelonites from 10 microns to 200 microns to particles that are formed during sudden coal and gas emissions in mines. Coal supermelonites are the main source of gas emission into the atmosphere of mine workings, as at their formation there is the disintegration of the supramolecular organization of coal macromolecule and generation of methane. Crushing of gas coals in the BDM inevitably leads to the formation of the explosive methane-coal mixture, which further enters the furnace of the boiler unit. As a result, a new functional scheme for automatic regulation and optimization of parameters of the BDM with a measuring and computing system for controlling the temperature of the gas medium, pressure drop, and a self-tuning microprocessor controller was developed. A technological scheme for installing control and measuring equipment has been developed for preparing coal for burning in a thermal power plant boiler unit. Explosion safety control in the technological cycle of preparing gas coals for burning is carried out constantly using methane and oxygen concentration sensors. The operability of the control system was confirmed on the industrial mill of the boiler unit BKZ-160-100PT TPP of "Kramatorskteploenergo" TPP. Keywords: ball drum mill, coal grinding, methane, explosion safety, control system.