發(fā)布時間：2018-01-06 06:00

  本文關(guān)鍵詞：城市污泥水熱提質(zhì)及重金屬析出特性研究　出處：《東南大學》2017年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 城市污泥 水熱提質(zhì) 物化特性 重金屬 穩(wěn)定化 燃燒特性

【摘要】：污泥是污水處理過程中產(chǎn)生的副產(chǎn)物,其高水分、多污染物(重金屬、病菌體等)、低熱值等特性成為其清潔利用的最大瓶頸。水熱處理是一種能夠?qū)崿F(xiàn)污泥無害化處理的新技術(shù),已成為當前研究的熱點之一。本文基于水熱處理方法,研究了不同水熱條件(反應終溫和反應停留時間)下,城市污泥水熱處理前后液相和固相產(chǎn)物的理化特性及重金屬的遷移與轉(zhuǎn)化規(guī)律;探討了水熱處理促進城市污泥中重金屬穩(wěn)定化的機制;研究了水熱固體產(chǎn)物的燃燒特性以及重金屬析出特性;從而為城市污泥的高效清潔利用提供實驗研究基礎(chǔ)。采用傅里葉變換紅外光譜(FTIR)、X射線衍射分析(XRD)、X射線熒光光譜分析(XRF)等儀器研究了不同水熱條件下城市污泥水熱處理后固相產(chǎn)物的理化特性。結(jié)果表明:污泥經(jīng)過水熱處理后具有較高的脫水率,特別是反應終溫為280℃時,處理后的污泥含水率降低至50%以下。污泥中含有的一些含氮、硫和氯的化合物也被脫除,從而減少了后期熱利用過程中污染物的生成。污泥經(jīng)過水熱后80%左右的礦物質(zhì)元素保存在固體產(chǎn)物中(Na除外)。隨著反應終溫增加,污泥中礦物質(zhì)元素更易于在液相產(chǎn)物中富集。延長反應停留時間則使得Al、Ca、Fe、Mg四種礦物質(zhì)更易于在固相產(chǎn)物中富集,而Na、K礦物質(zhì)更易于在液相產(chǎn)物中富集。采用歐盟提出的三態(tài)連續(xù)取樣法(BCR)及重金屬毒性浸出方法(TCLP),研究了污泥在水熱過程中,重金屬(As、Cd、Zn、Cr、Cu、Pb、Ni、Mn)遷移與轉(zhuǎn)化的特性;探討了污泥中重金屬水熱穩(wěn)定化的機理。結(jié)果表明:水熱處理后,污泥中大部分重金屬保存在固體產(chǎn)物中,少量保存在液體產(chǎn)物中(As除外)。水熱處理能夠促進城市污泥中的重金屬從不穩(wěn)定形態(tài)(酸溶態(tài)+還原態(tài))向相對穩(wěn)定形態(tài)(氧化態(tài))和穩(wěn)定形態(tài)(殘渣態(tài))轉(zhuǎn)化,從而實現(xiàn)重金屬的穩(wěn)定化。經(jīng)過水熱處理后,污泥中大部分重金屬(Pb、Cd除外)的浸出毒性大幅下降,尤其在反應終溫為280℃時,Ni、Cu、Zn、As的浸出濃度分別降低了 86.69%、97.18%、51.78%和75.9%。城市污泥中重金屬在水熱過程中的遷移分為三個過程:溶出或解吸過程、胞內(nèi)吸附及螯合過程、沉淀過程,這三個過程受到城市污泥本身的理化特性、水熱處理環(huán)境及重金屬結(jié)合形態(tài)的影響�；跓嶂胤治龇ㄑ芯苛顺鞘形勰嗨疅崽幚砬昂蠊坍a(chǎn)物的燃燒特性及重金屬的析出特性。結(jié)果表明:水熱處理后,固產(chǎn)物的著火溫度T1和燃燼溫度Th均升高,燃燒過程延長,而峰值溫度Tm則下降。經(jīng)過水熱處理后的城市污泥在揮發(fā)分燃燒階段的活化能較原始污泥有所提高,在碳燃燒階段的活化能低于原始污泥。重金屬析出特性結(jié)果表明:水熱固體產(chǎn)物經(jīng)過焚燒后,其含有的重金屬會更多的以相對穩(wěn)定或者穩(wěn)定形態(tài)存在于焚燒后殘渣物中。
[Abstract]:Sludge is a by-product produced in the process of sewage treatment, its high moisture, multi-pollutant (heavy metals, bacteria, etc.). The characteristics such as low calorific value have become the biggest bottleneck of its clean utilization. Hydrothermal treatment is a new technology which can realize the harmless treatment of sludge, which has become one of the hot spots of current research. This paper is based on hydrothermal treatment method. The physical and chemical properties of liquid and solid phase products and the migration and transformation of heavy metals in municipal sludge before and after hydrothermal treatment were studied under different hydrothermal conditions (reaction end temperature and reaction residence time). The mechanism of promoting the stabilization of heavy metals in municipal sludge by hydrothermal treatment was discussed. The combustion characteristics and heavy metal precipitation characteristics of hydrothermal solid products were studied. Thus, it provides the experimental research basis for the efficient and clean utilization of municipal sludge. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) are used. The physicochemical properties of solid phase products after hydrothermal treatment of municipal sludge under different hydrothermal conditions were studied by means of X-ray fluorescence spectroscopy (XRF) and other instruments. The results showed that the sludge had a high dehydration rate after hydrothermal treatment. In particular, when the final temperature is 280 鈩，

本文編號：1386570