| In today's increasingly scarce fossil energy,China has actively implemented the strategy of sustainable development and achieved a lot.Among them,heat pump technology is one of the important energy-saving technologies.Air source heat pumps have been rapidly developed due to their wide range of heat sources and they are easy to install and use,a significant contribution have been made by Air source heat pump to the energy conservation and emission reduction of the whole society.However frost problem in winter has become a bottleneck restricting the development of air source heat pump,wuzhou refrigeration company creatively used sodium formate solution of low freezing point to solve this problem in a low cost.they adopt the way of spray solution to solve the problem of the air source heat pump frost,this way had introduced a new problem-sodium formate solution can esaily errosion carbon steel heat exchanger,the cost of replacing carbon steel with stainless steel is really a big mount.what's more,stainless steel heat exchangers are not easy to integrate with other devices.Therefore,we hope to find a kind of anticorrosion method to delay the corrosion and retain the excellent performance of carbon steel heat exchanger.It is an economical and convenient method to add inhibitor to solution to delay corrosion.In this study,the properties of carbon steel and sodium formate media and the demands of enterprises under this working condition were firstly analyzed.Then,the four commonly used green and inorganic corrosion inhibitors--zinc sulfate,sodium molybdate,sodium silicate and sodium hetaphosphate--were found in the literature under similar working conditions.Subsequently,the static weight loss method was used to conduct preliminary experiments,and two kinds of obvious functions were selected,namely sodium molybdate and sodium silicate,and zinc sulfate for compounding.Then in 15% sodium formate solution for sodium molybdate,sodium silicate and different concentrations of zinc sulfate static coupon corrosion experiment,the concentration is 5 mg/L respectively,10 mg/L,15 mg/L,20 mg/L,25 mg/L,30 mg/L,blank control group to 0 mg/L,the results showed that sodium molybdate corrosion for zinc plated carbon steel in 15% sodium formate effect increases with the increase of concentration of sodium molybdate,if the concentration reaches to 30 mg/L,the relative corrosion rate reach to 57.4%;The corrosion inhibition rate for galvanized carbon steel in 15% sodium formic acid by sodium silicate increased first and then decreased with the increase of concentra-tion,reaching the maximum at 25mg/L,and the corrosion inhibition rate was 65.1%.The third step is based on the theory of compound with the possibility of the above three kinds of corrosion inhibitors were analyzed,and put forward the combination of two and three combinations of the mixed solution,and to a set of sodium molybdate and sodium silicate compound with verification,the results showed that the sodium silicate,sodium molybdate is 15 mg/L,5 mg/L,the anticorrosion rate was 61.3%,the relative anti-corrosion rate was 1.3 times than that with the concentration of sodium silicate role alone,1.8 times is with the concentration of sodium molybdate separate.In addition,this paper takes sodium silicate corrosion inhibitor as an example to compare and analyze the two antisepsis schemes of stainless steel heat exchanger and adding corrosion inhibitor,and the results show that adding corrosion inhibitor has obvious economic advantages.Each 11 kw frost-free air source heat pump unit using corrosion inhibitor can save about 2391.43 yuan per year. |
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