Study On Compatibility Of Bacteriostatic Scale Inhibitor In Circulating Water Of Power Plant

In this study,SSB16L and SS317L were used as the research materials to isolate and purify the sulfate-reducing bacteria(SRB)from the sludge in the bottom of the circulating cooling tower of a thermal power plant in Beijing.The experiment was to supplement the water with the circulating cooling water system of a thermal power plant in Beijing Recycled water for the experimental water,selected in the circulating cooling water treatment commonly used in the three categories of fungicides:non-oxidizing fungicide 1227(dodecyl dimethyl benzyl ammonium chloride),oxidizing fungicide sodium hypochlorite(NaClO),composite(XR-119);Class 4 scale inhibitors:phosphine scale inhibitor hydroxyethylidene diphosphate(HEDP)and 2-phosphonobutane-1,2,4-tricarboxylic acid(PBTCA),horse(HAMP),green scale inhibitor polyaspartic acid(PASP).The corrosion behavior of SRB and its biofilm on two kinds of stainless steel test pieces under the condition of reclaimed water were studied by X-ray photoelectron spectroscopy,contact angle,Zeta potential,atomic force microscopy,electrochemical polarization curve and AC impedance.The optimum concentration of the three kinds of fungicides is discussed,and the sterilization mechanism is explored.The optimum concentration of the four kinds of scale inhibitors is optimized,and the mechanism of scale inhibition and corrosion inhibition is discussed.Scale inhibitor and corrosion inhibition synergistic analysis;compatibility of SRB concentration of 3 times in the regeneration of water under the conditions of various types of fungicide scale inhibitor compatibility and compatibility mechanism of the study.The results are as follows:(1)The corrosion behavior of SRB and its biofilm on two kinds of stainless steel test pieces under the condition of reclaimed water was studied.The adsorption of SRB on stainless steel SS317L was strong,but it could inhibit the growth of adherent bacteria,which indicated that the adsorption of bacteria on the surface of stainless steel And the content of its metabolites is not positively correlated.The content of Cr in SS317L is higher,and the passivation film such as Cr03 and NiO is formed on the surface of SS317L.In particular,Cr03 can make the passivation film more dense,Play a more protective role.Therefore,the stainless steel SS317L in corrosion resistance of the durability and stability are significantly better than SS316L.(2)The results showed that the three fungicides showed excellent bactericidal effect,which effectively reduced the adsorption of bacteria on the surface of stainless steel.The bactericidal performance of the three fungicides was as follows:XR-119>1227>NaClO,the optimum concentration was 38mg/L,50mg/L,20mg/L,the corresponding sterilization rate was 94.7%,93.3%,90.1%.Compared with traditional fungicides,XR-119 has a more effective bactericidal rate and corrosion inhibition rate.XR-119 increases the positive charge density of the quaternary nitrogen in the molecule by the two positively charged N+ in the double quaternary ammonium salt molecule,which is favorable for the adsorption of the fungicide molecules on the bacterial surface,thereby altering the cell wall Permeability,so that the body rupture;the other hand,XR-119 polar groups and metal have a greater affinity and priority in the metal surface adsorption,the formation of hydrophobic surface,inhibit the microbial adsorption on the surface of stainless steel.In addition,the existence of XR-119 will increase the surface of the polarization resistance of the Rct value,with a certain degree of corrosion inhibition.(4)The results showed that the scale inhibition performance of four kinds of scale inhibitors was:HPMA>PBTCA>PASP>HEDP,the best concentration was 15mg/L,5mg/L,15mg/L,10mg/L,the corresponding scale inhibition rate was 95.7%,94.8%,93.4%,89.1%.HPMA and PBTCA,HPMA and HEDP have the synergistic effect of scale inhibition and corrosion inhibition,the best scale inhibition rate is 97.8%,96.4%,the best inhibition rate is 95%,96%,HPMA and PASP do not have the synergistic effect of scale and corrosion inhibition.(4)Studies have shown that the combination of fungicides and scale inhibitors when used sterilization,scale inhibition effect will be slightly decreased.Among them,HPMA + XR-119 and PBTCA+NaClO had lower bacterial concentration and 90%sterilization effect.HPMA + XR-119 and PASP+NaClO were not only good in scale inhibition,Scale efficiency of 88%and 89%,from a hydrophobic point of view,to a greater extent also slow down the deposition of biofilm.(5)In the experiment,the three groups have the advantages of sterilization,scale inhibition and corrosion inhibition synergies,and can provide the feasible reference for the actual production and application.Among them,PBTCA+NaCIO has the best bactericidal,scale inhibition,corrosion inhibition synergism,sterilization rate of up to 90%;scale inhibition rate of 82%,inhibition rate of 81%,the two can be well miscible,solution clarification And no turbidity phenomenon.For fouling,corrosive reclaimed water can choose PBTCA+NaCIO as the main compatibility agent to control the water quality of the fouling and corrosion tendency and microbial growth;for the scale of water quality can choose to HPMA+XR-119 or PASP+NaCIO combination of agents to control the water quality of the scaling and microbial growth.Compatibility of agents with excellent bactericidal scale and corrosion inhibition effect,but also help reduce the total amount of pharmaceutical dosage,reduce the dosing process,reduce production costs.