Experimental Study on Dynamic Simulation of Circulating Cooling Water Biofouling

Abstract

To study the formation mechanism and the chemical component of biofouling, the biofouling formation was simulated by the dynamic simulation device of circulating cooling water under the constant condition of 30°C and 0.4 m/s. The slime-forming bacteria and Iron Bacteria were selected as the research subject. Adsorption theory of bacteria in the solid/liquid interface was analyzed by colloidal stability theory. The two kinds of bacteria on heat transfer and the relationship between the total number of bacteria and fouling resistance were studied. The main component of biofouling was characterized using XPS. The results show that Iron Bacteria on the negative effects of heat transfer is greater than the slime-forming bacteria. The total number of bacteria is the maximum in the end of the induction period. The main component of biofouling of the slime-forming bacteria of iron bacteria is C, O, N, Fe, Ca, Mg, etc. The major elements of the ratio in different strains exists diversity in the stainless steel heat exchanger, but the most important elements is carbon and oxygen.

The Experiment Investigation of Cooling-Water Fouling Mechanism-Associated Water Quality Parameters in Two Kinds of Heat Exchanger

“…Researches have showed that the corrosion rate of metal surface is depended on the relationship between metal oxide solubility and pH value [8]. In acid solution, Fe 3+ is a kind of cathode oxidation accelerator.…”

“…After decades of exploration and research by scholars, many studies about cooling water fouling mechanism had been done [5][6][7], however, it was still difficult to understand. Generally, the influence factors of cooling water fouling could be summarized as follows: operation conditions [8][9][10], water quality With the technology development, more and more scholars concern on factors correlation analysis. Zhao and Chen [18] tried to relate a number of factors to fouling rate, and classified these factors into three categories: solution composition, operating parameters, and heat exchanger surface characteristics, then discussed each aspect from the crystallization viewpoint At present, the research about cooling water fouling mechanism is still inadequate and the relationship between water parameters and fouling resistance are not clear.…”