都會下水污泥及其焚化灰渣之輕質資材化研究; Lightweight Materials Study on Municipal Sewage Sludge and Incinerated Ash

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Title:	都會下水污泥及其焚化灰渣之輕質資材化研究;Lightweight Materials Study on Municipal Sewage Sludge and Incinerated Ash
Authors:	邱英嘉;Ing-Jia Chiou
Contributors:	環境工程研究所
Keywords:	下水污泥;發泡反應;燒結效應;孔隙結構;輕質建材;foaming reaction;sewage sludge;lightweight materials;pore structure;sinter effect
Date:	2005-01-18
Issue Date:	2009-09-21 12:14:24 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	目前廢污泥的資源化多半僅能部分摻加或取代傳統生料的方式，故資源化途徑與消耗量受到限制。本研究藉由下水污泥及其灰渣的特性加以調質與全程使用廢污泥，以達節能與資源化的創新性。本研究利用下水污泥及其焚化灰渣燒製人造骨材，並以下水污泥灰常溫產製發泡輕質材。探討「下水污泥及其焚化灰渣混合料燒製輕質骨材」、「下水污泥灰發泡輕質材的發泡行為與巨微觀特性」，以及「下水污泥灰發泡輕質材的熱傳機制與熱學行為」等三個研究子題。實驗結果顯示：首先，在「下水污泥及其焚化灰渣混合料燒製輕質骨材」方面，下水污泥及其灰渣可單獨或併同燒製常重或輕質骨材，下水污泥具成分調質劑的功能；灰渣中增加污泥用量會降低滾動造粒的成球率。在1,050-1,100˚C燒製範圍內，灰渣中每增加1%有機質可降低骨材的容積密度0.056-0.491g/cm3。純污泥灰的配比適合燒製常重骨材，較低下水污泥用量的配比(0-10%)適合燒製中密度骨材(1.0-1.6g/cm3)，較高下水污泥用量的配比(20-30%)則適合燒製低密度骨材(<1.0g/cm3)。下水污泥輕質骨材發泡混凝土的的熱傳導率介於0.216-0.354W/mºK，僅輕質混凝土的0.33-0.50。其次，在「下水污泥灰發泡輕質材的發泡行為與巨微觀特性」方面，下水污泥灰無法提供足量的鹼度促使鋁粉產生發泡反應，需提供相當於0.1 mole/L 的NaOH水溶液鹼度方有起始發泡反應，而最低的水泥量受制於抗壓強度，而非鹼度；一級廠污泥灰發泡輕質材比二級廠試體具有較高的發泡率、抗壓強度、熱傳導率，及較低的體比重。水泥的水化作用與金屬鋁粉的發泡反應分別以形成小於1µm及大於10µm的孔隙尺寸為主；在相同配比條件下，一級廠試體的總孔隙體積均高於二級廠試體；一級廠及二級廠下水污泥灰發泡輕質材的主要孔隙分布範圍分別為0.6-4.0μm及0.02-0.6μm。在高用水量與高量的大於10μm孔隙存在，容易形成開放且連通孔隙。使用廢五金粉末的試體發泡率平均約比試藥級鋁粉低18%，廢五金粉末用量較鋁粉增加約10-15%時，可獲得相近的發泡率與抗壓強度；廢五金粉末在試體中，其孔隙尺寸能較均勻分佈，別於鋁粉集中在大於10μm。最後，在「下水污泥灰發泡輕質材的熱傳機制與熱學行為」方面，下水污泥灰發泡輕質材的熱傳方式為固體傳導及氣體傳導，而輻射熱傳與自然對流均可忽略。下水污泥灰具有多孔特性、不規則顆粒形狀與低熱傳率(0.185 W/moK)的特性，配比參數對下水污泥發泡輕質材的熱傳導率影響權重依序為發泡劑用量(F/S)、水固比(W/S)、灰固比(A/S)。一級廠及二級廠下水污泥灰發泡輕質材的熱傳導率介於0.088-0.251W/moK及0.074-0.151W/moK，分別有75%及100%符合絕熱材料對熱傳導率的要求。而在高溫行為方面，下水污泥灰的燒結效應對發泡輕質材的體比重及體積收縮率的影響顯著於水化產物分解及脫水行為的影響；在1,000-1,093˚C高溫作用下，水泥量對下水污泥灰發泡輕質材的抗壓強度呈負效應，而增加下水污泥灰用量則因燒結效應能顯著提高抗壓強度。下水污泥灰發泡輕質材經1,093°C定溫焚燒後，因高溫熔流作用產生的緻密效應使0.1-1.0µm以下的孔隙明顯降低，而大於1.0μm的孔隙則明顯增加；前述溫度使試體達到液相燒結的粗化階段，使總孔隙體積較未焚燒前降低29.71%，而以毛細孔體積減少28.98%最顯著，而膠孔體積僅微幅變化，此時試體以存在大於1μm的孔隙為主。 Nowadays, most of the reuse and recycling of waste sewage sludge can only partially add in or replace the traditional raw materials. Therefore, recycling application and consumption are limited. In this study, the compositions of sewage sludge and its incinerated residues were adjusted, and sewage sludge was used for the whole process to save energy and to innovate the recycling methodology. Sewage sludge and incinerated residues were used to sinter artificial aggregates. In addition, sewage sludge ash was adopted to make foamy lightweight material under room temperature. Then, three topics, “Lightweight Aggregate Made from Sewage Sludge and Incinerated Ash”, “Foaming Behavior and Macro/Micro Properties of Foamy Lightweight Materials Made of Sewage Sludge Ash”, and “Thermal Conductivity Mechanism and Thermal Behavior of Sewage Sludge Ash Lightweight Materials”, were studies. The experimental results indicated that: In “Lightweight Aggregate Made from Sewage Sludge and Incinerated Ash”, sewage sludge alone or with incinerated residues could be sintered normal-weight or lightweight aggregates. Sewage sludge could be used as the adjusting agent of composition. Adding sewage sludge amount in incinerated residues would decrease the palletizing ratio. At 1,050-1,100˚C, increasing every 1% of organic matters in the sewage sludge ash would decrease the bulk density of aggregates by 0.056-0.491g/cm3. The mixing proportion of pure sewage sludge ash was suitable to sinter normal-weight aggregates, the mixing proportion with only 0-10% of sewage sludge in the incinerated residues was good to sinter moderate density aggregates (1.0-1.6g/cm3), and the mixing proportion with 20-30% of sewage sludge in the incinerated residues would be used to sinter high density aggregates (<1.0g/cm3). The thermal conductivity of lightweight aggregate foamed concrete made of sewage sludge ranged between 0.216 W/mºK and 0.354W/mºK, which was only 0.33-0.50 of conventional lightweight concrete. In “Foaming Behavior and Macro/Micro Properties of Foamy Lightweight Materials Made of Sewage Sludge Ash”, sewage sludge ash could not provide sufficient alkalinity to cause the foaming reaction of Aluminum powder until the addition of 0.1 mole/L equivalence of NaOH solution. The least cement amount in sewage sludge ash foaming lightweight materials (SSAFLM) were restrained by compressive strength, not alkalinity. Compared with secondary sewage sludge ash foaming lightweight materials (SSSAFLM), primary sewage sludge ash foaming lightweight materials (PSSAFLM) would have higher foaming ratio, compressive strength, thermal conductivity and lower bulk specific gravity. The hydration reaction of cement and foaming reaction of aluminum powder were mainly to produce the pores smaller than 1µm and pores larger than 10µm respectively. With the same mixing proportion, PSSAFLM would have greater total pore volume than SSSAFLM. The pore size distributions of PSSAFLM and SSSAFLM were 0.6-4.0μm and 0.02-0.6μm respectively. With high water usage and great amount of pores larger than 10μm, the open and connected pores would be easily formed. The foaming ratio of SSAFLM with mixed scrap metal waste powder was averagely lower than that of aluminum powder by 18%. When increasing the mixed scrap metal waste powder by 10-15% more than aluminum powder, SSAFLM would have similar foaming ratio and compressive strength. Pore sizes in SSAFLM with mixed scrap metal waste powder distributed evenly, which was different from that most of the pores in SSAFLM with aluminum powder were larger than 10μm. In “Thermal Conductivity Mechanism and Thermal Behavior of Sewage Sludge Ash Lightweight Materials”, at the room temperature in air, the thermal conduction of the SSAFLM would be via solid and gas conduction, and both radiative thermal conduction and natural convection could be ignored. The porous structure and irregular particles of the SSA make it have the characteristics of low thermal conductivity (0.185 W/moK). The influence weighting of mixing parameters to the thermal conductivity of SSAFLM were foaming agent amount (F/S), water-to-solids ratio (W/S), and sewage sludge ash amount (A/S) in turn. The thermal conductivities of PSSAFLM and SSSAFLM were 0.088-0.251 W/m.oK and 0.074-0.151W/m.oK respectively. Besides, 75% of PSSAFLM and 100% of SSSAFLM met the requirement of insulating materials in thermal conductivity. In high temperature behavior, the sintering effect of sewage sludge ash affected bulk specific gravity and volume shrinkage of SSAFLM more significantly than hydrates decomposition and dewater behavior did. Between 1000°C and 1093°C, the compressive strength of SSAFLM was in an inverse relationship with the amount of cement, and increasing the amount of sewage sludge ash would enhance the strength significantly. After fired at 1093°C, SSAFLM completed the enlarging stage of liquid phase sintering, and thus decreased total pore volume by 29.71% averagely than that before fired. Of which, 28.98% out of 29.71% was owing to the decrease of capillary pore volume, and however, the gel pore volume only changed slightly. In the meantime, most of the pore sizes in SSAFLM were larger than 1.0μm.
Appears in Collections:	[Graduate Institute of Environmental Engineering ] Electronic Thesis & Dissertation

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