| The fouling is a common problem in the field of power system, chemical and other industries. How to fulfill anti-scaling and descaling target is a technical problem. For many years, because of simple, economic, pollution-free advantages, the magnetic field for anti-scaling and descaling water treatment technology has been widely studied.This paper designed a set of bipolar pulse magnetic field generator and made simulation analysis of the bipolar pulse magnetic field inside the air-gap. First of all, we calculated uniformity of magnetic induction intensity was less than 0.15% in the water treatment chamber. It meets the requirements of magnetic field uniformity in anti-scaling experiments. According to the basic theory of Maxwell’s equations, we found that magnetic induction intensity distribution of 8-fan assembled one ring-type permanent magnets can’t be calculated through the basic theory method of electromagnetic field, common equivalent electric current and the equivalent magnetic charge method. Solving the problem must use the numerical calculation of finite element method. The simulation got magnetic induction intensity distribution inside the water treatment chamber by ANSYS software. Namely, magnetic induction intensity remained 0.4T in the effective distance of 0.02 m.When the ring type device rotates, the magnetic induction intensity in the center of processing chamber can range from-0.4T to 0.4T changing alternately four times. In the end, magnetic induction intensity is 0.4T of bipolar pulse magnetic field in the pipe and is vertical with the direction of water flow.In this paper we made a mini-circulating water system to do anti-scaling experiments with multi-parameter real-time monitoring function. It include the bipolar pulse magnetic field generator, circulating water device and measuring instruments. Lab X software was used to on-line monitoring the pH, electrical conductivity and temperature at the same time. It shorten the time interval of data recording and reduce the workload of manual recording. We verified the repeatability of anti-scaling experiments through the preliminary experiment. Orthogonal experiment data showed that the best scale inhibition effect was the condition of the initial concentration of calcium ion as 6mmol/L, pulse frequency as 40 Hz and circulating water temperature as 40°C.The highest scale inhibition rate was 49.33%. We did the single factor analysis of variance for the results of orthogonal scale experiment and get the influence degree of the scale inhibition rate with the order as pulse frequency, the initial calcium ion concentration and water temperature in three factors and three levels layout. Namely, the initial concentration of calcium ion is 5mmol/L, pulse frequency is 40 Hz and circulating water temperature is 40°C. The experiments showed that pH values vibrated with the temperature, the higher the temperature increased, the more violently pH waved.Finally, we studied the concentration with calcium ion, conductivity and time correlation, and set up the BP neural network model basing on pulsed magnetic field orthogonal scale experiment and have a scale parameter optimization in combination with the BP model and genetic algorithm. The result shows that pulsed magnetic field plays an important role in promoting for steady of circulating water solution ion with the increase of frequency, calcium ion balance quickly. We also established the forecast model of BP neural network as the fitness function of genetic algorithm. We got the maximum number 84.37% of scale inhibition rate in a certain range, namely, the initial concentration of calcium ion is 4.45mmol/L, magnetic induction intensity is 0.395 T, pulse magnetic field frequency is 77.5Hz and circulating water temperature is 56.86°C. |
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