| Through the fieldwork of the circulating water system in the textile factory,it was found that there is a serious scale phenomenon in the water system,and the water droplets cannot be fully atomized by nozzles,so the efficiency of heat and moisture exchange between the air and water was low,and there were along with problems such as algae and bacteria breeding,silt deposit and corrosion under the scale,affecting the service life of equipment and pipes seriously.In addition,investigation found that circulating water equipment electricity consumption accounts for about 25%of the total electricity consumption,and water consumption is accounted for about 80%of the total water consumption,and the problem of scaling restricts the development of textile air-conditioning to low-carbon,green,circular textile economy.Therefore,combined with the existing water treatment methods,through making economic analysis of the application of the water treatment methods in circulating water system,select an economically effective approach to solve the problem of the water system,such as the problem of running not so well and low energy efficiency caused by circulating water quality problem,that was the scale,in the textile factory.After market research and access to information,there are five commonly used water treatment methods,respectively,1)adding scale inhibitors;2)electronic water treatment;3)ultrasound water treatment;4)electro-adsorption water treatment;5)reverse osmosis water treatment.Through economic analysis of principle and applicable place of these water treatment methods,the initial costs of equipment investment,operation management costs and the ease of maintenance,it was found that the method of adding scale inhibitor slightly better than the other four water treatment methods,Therefore,the water treatment method with scale inhibitor was chosen to treat the circulating water in textile mills.After that,the selection of experimental sites was carried out.According to the National Water Quality Standard（GB/T14848-2017）,the p H and hardness of the circulating water in Xian yang and Xi’an were analyzed,and it was found that the average total hardness of the circulating water in Xian yang was 476mg/L,the average total hardness of Xian yang running water was 174.7mg/L,the average total hardness of the circulating water in Xi’an was 331.3mg/L,the average total hardness of Xi’an running water was 153.3mg/L,the average total hardness of the circulating water and running water in Xian yang were144.7mg/L and 21.4mg/L respectively.There was little difference between the p H of the circulating water in the two places,so choose the site with a high hardness,that is,Xian yang textile factory to carry out the experiments of water quality.Investigation on scale of circulating water system in Xian yang textile factory,and utilizing Scanning Electron Microscope and Energy Dispersive Spectrometer to analysis the appearance and element of the scale sample,we found that the main categories of the scale are three,these were magnesium scale,carbonate scale and silicate scale,and the fiber was obviously mixed with scale.Among the methods of adding scale inhibitors,two kinds of scale inhibitors with low economic cost and wide application were selected to test their performance.One acidic scale inhibitor was HEDP,an alkaline scale inhibitor called PC2566),taking water samples from circulating water in Xian yang Textile Factory,we tested the static scale inhibitor rate and their corrosion on water system pipes and equipment,the conclusion was:best use ratio of HEDP was obtained,that was:scale inhibitor/circulating water=2.5mg/1000m L,the scale resistance rate was 89%with this ratio,while the best effect of PC2566 was used with a ratio of scale inhibitor/circulating water=0.2m L/1000m L,the scale resistance rate was 69.3%with this ratio,according to the best use of the ratio,we did the test of corrosion with the mixed liquid of scale inhibitor and circulating water,and the test cycle was one month,such as in the corrosion test of HEDP,we found that the weight of galvanized steel sheet was reduced 7.685%,and in the corrosion test of PC2566,the weight of galvanized steel sheet was only reduced 4.797×10-3%.Finally,compared with the scale inhibitor rate and characteristics of corrosion of these two scale inhibitors,we chose the low-corrosive alkaline scale inhibitors PC2566,as it was considered to be better for water system pipes and equipment,and then applied it to the circulating water system in textile mills.The water quality of circulating water and replenishing water（local tap water）in two air conditioning rooms with similar operating conditions in Xian yang Textile Factory were tested respectively.One of the air conditioning rooms was 3#which adding scale inhibitor,the other one was 5#which not adding scale inhibitor,as a blank control group.The volume of both rooms is 17.404 m~3,according to the optimum concentration ratio,which is scale inhibitor/circulating water=0.2m L/1000m L,so the initial dosage of scale inhibitor is3.4808 L.In order to obtain the law of water quality change and reflect the difference of water quality change between adding scale inhibitor and not adding scale inhibitor.According to"Water Quality of Heating and Air Conditioning System"（GB/T29044-2012）,the main test contents were calcium hardness,total hardness,total alkalinity,p H and conductivity of circulating water and replenishing water（local tap water）for 35days.The change of water quality is:after adding scale inhibitor,the indices of circulating water rises faster than the circulating water without adding scale inhibitor,the water is clear,there was no fouling phenomenon;the indices of circulating water in the non-adding scale inhibitor are less than that of adding scale inhibitor,while the indices of the circulation water had been increasing all the time,and the value was far exceed the water quality index standard value,the water in 5#air conditioning room was turbid,and there had fouling phenomenon.Therefore,the water treatment approach of adding scale inhibitors can be used to deal with the circulating water in textile mills,so that the goals of reducing scale and optimizing the problems of water system when it running,saving the water resources can be attained. |
