The Effect of the Design Paddle Electrothermomechanical System on Duration of Heating Substance in the Biogas Reactor

For rational use organic raw materials, it is necessary to create microclimate parameters in biogas reactors that correspond to conditions anaerobic fermentation. The creation of these parameters and the selection of the necessary equipment for this is a complex and important issue from the point of view of saving electricity and increasing the interest investors in introduction of biogas production. Purpose of study was to investigate influence of positional law of changes in applied power to the heating device of an electrothermo mechanical system with different paddle designs. The electrothermomechanical system includes paddles with surface-mounted electric heaters protected by a steel casing. In the research, paddles of two designs were used, namely: steel monolithic and steel hollow paddles, the cavity of which is filled with a filler (wax). To achieve goal, mathematical model was built using differential equations. Numerical calculations were performed in the Wolfram Mathematica application program. The power applied to the electric heater changed according to the positional law. The result of the conducted research was obtaining graphic dependences temperature change of substance using monolithic and wax-filled paddles. It is established that electric heating of volume <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{0.04}\ \mathbf{m}^{\mathbf{3}}$</tex> of matter from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{34}\ {}^{\circ}\mathbf{C}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{35.8}\ {}^{\circ}\mathbf{C}$</tex> using paddles whose cavity is filled with wax occurs faster by 8.2% on average. The average rate of increase in temperature substance in first 100 seconds of heater operation is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{0.0008}\ {}^{\circ}\mathbf{C}/\mathbf{s}$</tex>, which is 56% more than the average rate of increase in temperature when using monolithic steel paddles. The conducted research made it possible to establish that average value temperature of spiral heating cable placed on paddle with filler (wax) is on average 4.6% higher compared to temperature spiral of heating device placed on monolithic steel paddle. Provided it is placed in a biogas reservoir (reactor) with a volume of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{0.04}\ \mathbf{m}^{\mathbf{3}}$</tex>. In work shows a graphical dependence and established for the first time that in the first 200 seconds of operation the heating device, change in temperature filler (wax) occurs according to a parabolic law. The obtained positive results can be used in investigation and creation systems for automatic control of heating devices in reactors, which will allow create energy-efficient systems and increase profitability of processes of heating substances in reactors.