Dynamic Model of a High-Capacity Electric Boiler with an Immersed Electrode

The chapter carried out research of the process of heating water in high-capacity electric boiler with an immersed electrode. Attention is paid to the obtaining the dynamic model of the heating process, as well as building charts of the dynamic characteristics of the boiler. An analysis of the existing models high-capacity electric boiler with an immersed electrode was carried out. In the article, three sections of heat exchange are distinguished for a boiler with immersed electrodes. The first section is the lower one, in which heat energy is not transferred. The water actually does not come into contact with the electrodes and does not heat up. The water in the container expands, the flow rate decreases. This section is necessary due to the design features of the boiler with movable screens. In the next section, water enters the space where the current flows from the electrode to the counter electrode and, accordingly, heating begins. Next, the water gradually rises up, passes the area of contact with the electrode and actually completes its heating. In the upper part of the boiler tank, the heated water mixes with the water that gets there bypassing the heating section. After that, the water of the final temperature leaves the boiler and goes to the heat exchanger. Obtained mathematical models of dynamics for the heating section and the mixing section. Modeling of transient processes at various boiler load changes was carried out. According to the simulation results, the larger the position of the screens changes, the longer the water heating process lasts. In turn, the duration of the heating process depends on the speed of changing the position of the screens. The speed of change of electric load of existing models of electric boilers with a submerged electrode allows them to be used as consumers-regulators for secondary regulation of frequency and power in the power system. In order to analyze the operation of the control system of this boiler according to the water temperature at the boiler outlet, it is necessary to conduct additional studies.