發(fā)布時(shí)間：2018-06-26 00:00

  本文選題：鐵釋放 + 管道腐蝕產(chǎn)物　； 參考：《哈爾濱工業(yè)大學(xué)》2015年博士論文

【摘要】：供水管網(wǎng)水質(zhì)安全是當(dāng)前供水行業(yè)的熱點(diǎn)問題之一,隨著研究的逐步深入,供水管道鐵腐蝕和鐵釋放已變成了兩個(gè)意義不同的概念。本文首先進(jìn)行了城市供水管道腐蝕產(chǎn)物的物理化學(xué)特性和管道鐵釋放規(guī)律的研究,然后,從鐵形態(tài)學(xué)角度,進(jìn)行了管道中鐵的遷移轉(zhuǎn)化研究,之后,基于鐵釋放機(jī)理分析,建立了管道鐵釋放通量模型和城市供水管網(wǎng)鐵釋放風(fēng)險(xiǎn)評(píng)價(jià)體系,最后提出了控制管道鐵釋放的管理措施。實(shí)驗(yàn)數(shù)據(jù)說明城市舊有水源出廠水水質(zhì)腐蝕性較高,從而導(dǎo)致管段內(nèi)壁腐蝕嚴(yán)重,形成了發(fā)達(dá)且分層的腐蝕管垢層。鑄鐵管和鍍鋅鋼管腐蝕產(chǎn)物的主要元素均為鐵和氧,兩種元素在鑄鐵管和鍍鋅鋼管腐蝕產(chǎn)物中的質(zhì)量百分比之和分別平均大于80%和90%。晶態(tài)鐵氧化物主要是磁鐵礦、針鐵礦、纖鐵礦、四方纖鐵礦、綠銹和菱鐵礦,但是,在不同的管道腐蝕產(chǎn)物中,晶態(tài)鐵氧化物的含量存在差異。硫酸根濃度從30mg/L提高到195mg/L和氯離子濃度從10mg/L提高到190mg/L,管道鐵釋放速率均明顯上升；pH值從7.05提高到8.25和堿度從125mg/L提高到185mg/L,管網(wǎng)鐵釋放均得到有效控制；溶解氧在8.0mg/L到16.0mg/L范圍內(nèi)變化,鐵釋放速率先下降后上升；余氯在0mg/L到1.9mg/L范圍內(nèi)變化,鐵釋放先抑制再促進(jìn)后趨于穩(wěn)定。在管網(wǎng)的運(yùn)行管理中,水流方向的改變會(huì)在短時(shí)間對(duì)鐵釋放產(chǎn)生劇烈的影響；流速在超出一定臨界值之后,流速變大,鐵釋放量隨之變大；隨著水力停留時(shí)間的延長(zhǎng),管道鐵釋放量增加程度明顯。通過7-12月份長(zhǎng)達(dá)140多天的長(zhǎng)期檢測(cè)管網(wǎng)鐵濃度變化和相關(guān)水質(zhì)指標(biāo),分析發(fā)現(xiàn)溫度是影響管網(wǎng)季節(jié)變化中鐵釋放的重要因素。硫酸根和氯離子對(duì)二價(jià)鐵氧化速率影響微弱；pH值從7.03提高到7.89,二價(jià)鐵氧化速率急劇上升；在恒定pH值條件下,溶解氧從2.49mg/L提高到8.46mg/L,二價(jià)鐵氧化速率變化不大；堿度提高,二價(jià)鐵氧化速率會(huì)變大；一氯胺在0～1.12mg/L范圍內(nèi)升高,二價(jià)鐵氧化速率隨之變大。管網(wǎng)水體中鐵顆粒物與濁度存在正相關(guān)性。硫酸根和氯離子分別在34-389mg/L和9-292mg/L變化,鐵顆粒物的形成量變化不大；pH值從7.03提高到7.89,鐵顆粒物的形成量上升；溶解氧從2.49mg/L提高到8.46mg/L,鐵顆粒物的形成量變化不大；堿度從118mg/L提高到247mg/L,鐵顆粒物的形成量上升；一氯胺在0～1.12mg/L范圍內(nèi)升高,鐵顆粒物的形成量隨之增加；隨著時(shí)間的累積,鐵顆粒物的形成量也會(huì)逐漸增加。在管道鐵釋放較高階段,管道腐蝕產(chǎn)物中的總鐵以及游離氧化鐵含量較高,不穩(wěn)定鐵化合物和過渡態(tài)鐵化合物含量會(huì)上升,隨著水溫下降以及溶解氧、pH、堿度等逐漸上升,管道鐵釋放水平下降,管道腐蝕產(chǎn)物中的總鐵以及游離氧化鐵含量也隨之降低,不穩(wěn)定鐵化合物和過渡態(tài)鐵化合物同時(shí)被緩慢氧化,形成穩(wěn)定的磁鐵礦和針鐵礦。硫酸根在凈水工藝中基本沒有變化,氯離子只在預(yù)氯化和混凝階段略有增加,堿度在混凝階段有所下降,但是氯離子和堿度的變化均微弱。pH在混凝過程中會(huì)有所下降,溶解氧會(huì)受到臭氧工藝的影響。拉森指數(shù)隨著混凝劑投加量的增加而上升；在研究期間的8月份到11月份,碳酸鈣沉淀勢(shì)CCPP在時(shí)間上呈現(xiàn)上升趨勢(shì),在工藝單元中變化微弱。采用一維移流擴(kuò)散方程和物料平衡方法兩種方式,建立了城市供水管網(wǎng)鐵釋放通量模型,通過比較管道鐵釋放量的實(shí)測(cè)值與管網(wǎng)鐵釋放通量模型的預(yù)測(cè)值,兩者的絕對(duì)誤差在-0.008-0.019mg/L,相對(duì)誤差在-6.74-7.77%,該模型對(duì)管道系統(tǒng)的鐵釋放預(yù)測(cè)較為準(zhǔn)確。基于管網(wǎng)鐵釋放的不確定性,結(jié)合系統(tǒng)工程和運(yùn)籌學(xué)知識(shí),建立了城市供水管網(wǎng)鐵釋放風(fēng)險(xiǎn)模糊評(píng)價(jià)體系,力求表達(dá)供水管網(wǎng)水體中鐵濃度存在的風(fēng)險(xiǎn)狀況,優(yōu)化日常鐵檢測(cè)取樣點(diǎn)位置和便于供水行業(yè)運(yùn)行管理。針對(duì)南水北調(diào)中線工程通水后的天津市城市供水管網(wǎng)鐵釋放風(fēng)險(xiǎn)問題,從管道腐蝕產(chǎn)物的物理化學(xué)特性,水質(zhì)特點(diǎn)與水力條件三方面分析,在做好水源地水質(zhì)保護(hù)和長(zhǎng)距離輸水管渠水質(zhì)不被污染的前提下,城市供水管網(wǎng)不會(huì)發(fā)生大面積的“黃水”現(xiàn)象。但是,需要做好管網(wǎng)供水分界線和重點(diǎn)管段的水質(zhì)安全保障。
[Abstract]:The water quality safety of the water supply network is one of the hot issues in the current water supply industry. With the gradual deepening of the research, the iron corrosion and iron release of the water supply pipeline have become two different concepts. Firstly, the physical and chemical properties of the corrosion products of the urban water supply pipeline and the law of the release of the iron in the pipeline are studied, and then, from the iron morphology angle. On the basis of the analysis of iron release mechanism, the Guan Daotie release flux model and the iron release risk assessment system of urban water supply network were established. Finally, the management measures to control the release of iron in the pipeline were put forward. The experimental data showed that the water quality of the old water source in the city was highly corrosive, thus leading to the result of the experimental data. The corrosion of the inner wall of the tube formed a developed and stratified corrosion scale. The main elements of the corrosion products of cast iron pipes and galvanized steel pipes are iron and oxygen. The percentage of the two elements in the corrosion products of cast iron pipes and galvanized steel pipes is more than 80% and 90%. crystalline iron oxides are mainly magnetite, goethite and fibrite. Tetragonal iron ore, green rust and siderite, but there are differences in the content of crystalline iron oxide in different pipeline corrosion products. The release rate of pipe iron is obviously increased from 30mg/L to 195mg/L and the concentration of chloride ion from 10mg/L to 190mg/L, and the pH value increases from 7.05 to 8.25 and alkalinity increases from 125mg/L to 185mg/L. The release of iron in the pipe network is effectively controlled, the dissolved oxygen changes in the range of 8.0mg/L to 16.0mg/L, the release rate of iron decreases first and then rises, and the residual chlorine changes in the range of 0mg/L to 1.9mg/L, and the release of iron is suppressed first and then then tends to stabilize. When the flow velocity exceeds a certain critical value, the flow velocity becomes larger and the release amount of iron becomes larger. With the prolongation of the hydraulic retention time, the release of iron in the pipeline increases obviously. Through a long period of more than 140 days in 7-12 days, the iron concentration changes and the related water quality indexes are detected, and the results show that the temperature is influenced by the iron release in the seasonal change of the pipe network. The effect of sulphate and chloride ions on the oxidation rate of two valent iron is weak, the pH value increases from 7.03 to 7.89, the oxidation rate of two valence iron oxide increases sharply, and the dissolved oxygen is increased from 2.49mg/L to 8.46mg/L under constant pH value, and the rate of two valence iron oxidation is not changed little; the oxidation rate of two valence iron will increase with the increase of alkalinity; and the one chloramine is 0. The oxidation rate of two iron oxide increases with the increase of 1.12mg/L range. The iron particles and turbidity are positively correlated with the iron particles in the pipe network. The variation of the sulfate and chlorine ions in 34-389mg/L and 9-292mg/L, the formation of iron particles is little, the pH value increases from 7.03 to 7.89, the formation of iron particles increases, and the dissolved oxygen is increased from 2.49mg/L. At 8.46mg/L, the formation of iron particles changed little; the alkalinity increased from 118mg/L to 247mg/L, the formation of iron particles increased; the formation of iron particles increased in the range of 0 to 1.12mg/L, and the formation of iron particles increased with the accumulation of time. The content of total iron and free iron oxide in the corrosion products is higher, the content of unstable iron compounds and transition iron compounds will rise. With the decrease of water temperature and dissolved oxygen, pH, alkalinity and so on, the release level of pipe iron decreases, and the total iron and free iron oxide content in pipeline corrosion products also decrease, and the ironchemical compound is unstable. The iron compounds and transition states were slowly oxidized to form stable magnetite and goethite. The sulphuric acid roots did not change basically in the water purification process, and the chloride ions only slightly increased in the prechlorination and coagulation stages, and the alkalinity decreased in the coagulation stage, but the changes of chloride ions and alkalinity decreased in the process of coagulation, which decreased in the coagulation process. The dissolved oxygen is affected by the ozone process. The Larsen index increases with the increase of coagulant dosage; in the period of August to November, the CCPP of the calcium carbonate precipitate potential is on the rise in time, and the change is weak in the process unit. The city is established by two ways of using the one-dimensional flow diffusion equation and the material balance method. The iron release flux model of the water supply pipe network, by comparing the measured value of the pipeline iron release and the prediction of the iron release flux model of the pipe network, the absolute error between the two is -0.008-0.019mg/L, the relative error is in the -6.74-7.77%, the model is more accurate to the iron release prediction of the pipeline system. With the knowledge of operational research, the fuzzy evaluation system of iron release risk in urban water supply network is established to express the risk of iron concentration in water supply network, optimize the location of the daily iron detection sampling point and facilitate the operation and management of the water supply industry. The risk of iron release from the urban water supply network of Tianjin city after the middle route of the south to North Water Transfer Project is released. From the three aspects of the physical and chemical characteristics of the pipeline corrosion products, the water quality characteristics and the hydraulic conditions, the urban water supply network will not have a large area of "yellow water" on the premise of the water quality protection and the water quality of the long distance water pipeline. However, it is necessary to do well the dividing line and the key pipe section of the pipe network. Water quality safety guarantee.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU991.33
，

本文編號(hào)：2068118