模擬利用水熱處理進行有害事業廢棄物的資源化技術成效

Simulation of the Efficiency by Using Hydrothermal Treatment Technique Applied on the Recycling of Hazardous Industrial Solid Wastes

施孟豪(Meng-Hao Shih)

指導教授 ： 黃武章

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2015年)

https://doi.org/10.6346/NPUST.2015.00094

摘要

本研究利用Gambit及Fluent等計算流體力學模擬軟體來進行水熱環境模擬，同步搭配實體水熱反應器實驗來進行一般及有害事業廢棄物的處理，探討其處理成效並且將水熱法作為一種廢棄物資源化的有力技術。
在水熱模擬方面，初始階段(0分鐘處)壓力由底部產生並逐漸加壓，底部壓力為3 atm；模擬中段(模擬60分鐘處)時蒸氣產生速度較凝結沉降的速度快，故底部介面蒸氣壓力略高於頂部，為20.9 atm；中後段至最終段(模擬時間80分鐘至90分鐘)時，其內部蒸氣壓力趨於平衡，壓力為20.0 atm，此一平衡為一穩定的動態平衡。
以水熱法進行螢光粉的釔回收，螢光粉原樣中的釔含量為2.85 wt %，單純使用鹽酸進行回收之效果最高可達57.46 wt %；鹽酸混合草酸進行處理，發現螢光粉中的鈣會與草酸形成大量草酸鈣沉澱，而鈮與釹則有少量沉澱，導致釔難以回收。
將鋁渣與廢玻璃粉末做為材料以水熱法在鹼性溶液中進行沸石的合成，從SEM/EDS、XRD、FI-IR的分析及BET試驗結果可得知其結果是有效的，其中以150°C/5M NaOH/2小時條件合成之樣品成效最好。
以120°C低溫水熱法進行土壤重金屬砷的去除，以不改變土壤性質與晶相的條件進行水熱處理，由SEM/EDS分析可知低溫水熱條件並不會造成土壤性質與晶相改變；經原子吸收光譜法進行土壤中砷濃度的檢測，結果顯示可去除土壤中92.7% 的重金屬砷。
在飛灰重金屬的水熱促溶試驗中，操作溫度在90°C的水熱條件下對於鉛的去除效果最好。溶劑選用上使用去離子水的效果最佳，其鉛溶出率可達68.98%。而在水熱條件下去除效果隨溫度提升而下降，故飛灰重金屬的水熱促溶效果在高溫條件下是無效的。

關鍵字

水熱法 ； CFD模擬 ； 釔回收 ； 鋁渣 ； 重金屬去除

並列摘要

The study used CFD simulation software (Gambit and Fluent) to simulate a hydrothermal environment, and a hydrothermal reactor to treat general and hazardous industrial wastes in order to investigate the effectiveness of hydrothermal treatment. The hydrothermal method was used as a powerful recovery technique of wastes.
In the simulation of hydrothermal reaction, at the initial phase (0 minute), the pressure generated from the bottom and gradually pressurized to 3 atm. In middle stage (60 minutes), vapor generation rate was faster than the coagulation, so the pressure on the interface of bottom was slightly higher than the top of the reactor at 20.9 atm. In later stage to the final stage (simulation time in 80 to 90 minutes), the vapor pressure tended to be balanced, with an internal pressure of 20.0 atm. At this stage, this balance was observed as a stable dynamic balance.
The hydrothermal method was used to recover yttrium of phosphor. The yttrium content of phosphor was 2.85 weight %. The recovery effect of using hydrochloric acid increased to 57.46 weight %. When mixing hydrochloric acid and oxalic acid to treat phosphor, it was found that oxalic acid with the calcium of phosphor formed large amounts of calcium oxalate precipitation, and small amounts of precipitated niobium and neodymium. This was observed to cause difficulty in yttrium recovery.
To synthesize zeolites, the aluminum slag and waste glass powder as material in alkaline solution was carried out by using the hydrothermal method. From the SEM/EDS, XRD, FI-IR analysis and BET tests, the results probed the method to be effective. The best condition to synthesize samples was at 150 ° C / 5M NaOH / 2 hours.
At 120 °C low-temp hydrothermal method to remove arsenic in soil with conditions of hydrothermal treatment, did not change the properties and crystal phase in the soil. The SEM / EDS analysis showed that low-temp hydrothermal conditions did not cause changes of properties and crystal phase in the soil. By using atomic absorption spectrometry to determine the concentration of arsenic in soil, the result showed that arsenic can be removed at 92.7% from soil.
In the hydrothermal leaching of heavy metals in fly ash, the best hydrothermal condition of removing lead was operated at a temperature of 90 ° C. The best solvent was deionized water, and the leaching rate of lead was up to 68.98%. Under hydrothermal conditions, the removal effect decreased when temperature increased. The effect of high-temp hydrothermal leaching of heavy metals in fly ash is ineffective.

並列關鍵字

Hydrothermal method ； CFD simulation ； Recovery of yttrium ； Aluminum slag ； Removal of heavy metals

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