臺灣博碩士論文加值系統

本研究是以連續式流體化床，探討中華映管公司所排出廢水污泥之乾燥實驗。實驗是在內徑90毫米，高1.3公尺的流體化床內進行，了解入口氣體速度(1.13~1.46Umf)、入口氣體溫度(30~60oC)、床體溫度(30~60oC)、污泥進料速率(0.83~1.33g/s)及靜床高對於乾燥特性的影響。在此研究中，廢水污泥加入玻璃珠於流體化床內進行乾燥，在不同操作條件下測量入口、出口氣體濕度及溫度，隨時間之變化來計算污泥含水量及其乾燥速率。實驗結果發現，乾燥效果會隨著入口氣體速度、進氣溫度、床體溫度、靜床高增加而增加，但是隨著污泥的進料速率增加而減少。連續式流體化床乾燥器的實驗結果可以用連續式乾燥動力和出口污泥的滯留時間分佈來預測。本研究之出口污泥溼度的計算值與實驗值誤差在15%以內。

The drying characteristics of sewage sludge from CPT (Chinese Picture Tube Co.) were experimentally studied in a continuous fluidized bed. Experiments were carried out in a 90mm I.D., 1.3m in height laboratory-scale fluidized bed to visualize the effects of superficial air velocity (1.13~1.46Umf), inlet air temperature (30~60oC), bed temperature (30~60oC), feeding rate of sewage sludge (0.83~1.33g/s) and static bed height (130~190 mm). Sewage sludge was continuously fed to a fluidized bed with glass beads being fluidized by hot inlet air, then the time variations of humidity and temperature of inlet and outlet air were measured under different operating conditions.
The experimental results indicate that the drying degree increases with increasing superficial air velocity, inlet air temperature, bed temperature and static bed height, but with decreasing feeding rate of sewage sludge. The performance of the continuous fluidized bed dryer can be predicted from continuous dryer kinetics and the residence time distribution of exited sludge. The calculated outlet moisture contents are in agreement with the experimental data within 15% in this study.

ACKNOWLEDGEMENTS…………………………………………..iii
ABSTRACT(ENGLISH)………………………………………………..iv
ABSTRACT(CHINESE)………………………………….……………v
LIST OF TABLES………………………………………………………ix
LIST OF FIGURES………………………………………………………x
NOMENCULTURE……………………………………………………xvi
CHAPTER
1 INTRODUCTION.........................................................................1
2 LITERATURE SURVEY……………………………………...7
2.1 Drying kinetics……………………………………………...7
2.1.1 Drying kinetics for fluidized bed dryer.…...…………7
2.1.2 Constant rate period…………………….…………..11
2.1.3 Falling rate period…………………………………..11
2.1.4 Drying mechanism in a media fluidized bed………..13
2.2 Effect of gas velocity………………………………………16
2.3 Effect of temperature………………………………………16
2.4 Effect of feeding rate………………………………………20
2.5 Effect of static bed height………………………………….20
2.6 The degree of drying sludge……………………………….23
2.7 Predicting the performance of a continuous fluidized bed
dryer……………………………………………………….26
3 EXPERIMENTAL……………………………………………...29
3.1 Apparatus…………………………………………………..29
3.2 Experimental procedure……………………………………33
3.2.1 Sludge drying in a continuous fluidized bed dryer…..33
3.2.2 Residence time distribution of solids in the continuous
fluidized bed………………..………...……………...35
3.3 Experimental materials…………………………………….37
3.4 Data arrangement…………………………….…………….39
3.4.1 Drying rate of sludge………………….……………..39
3.4.2 The degree of drying sludge…………………………40
4 RESULTS AND DISCUSSION...……………………………42
4.1 Effect of superficial air velocity…………………………..46
4.2 Effect of bed temperature…………………………………46
4.3 Effect of inlet air temperature……….…………………….49
4.4 Effect of sludge feeding rate……………………….………49
4.5 Effect of static bed height………………………….………52
4.6 Particle size distribution of sludge after drying……………52
4.7 Degree of drying sludge…………………………………...59
4.8 Predicting the performance of a continuous fluidized
bed dryer…….…………………………………………….62
5 CONCLUSIONS……………………………………………….75
REFERENCES………………………………………………………….76
APPENDIX A………………………………………………………..79
APPENDIX B………………………………………………………..80
APPENDIX C………………………………………………………..81

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