臺灣博碩士論文加值系統

本研究是以批式流體化床，探討映管工廠所排出廢水污泥之乾燥實驗。實驗是在內徑90毫米，高1.36公尺的流體化床內進行，了解入口氣體速度(1.18~1.35Umf)、入口氣體溫度(30~60oC)、床內溫度(50~80oC)、污泥含水量(16.5~42.8%)、玻璃珠和污泥重量比(12~20)和污泥粒子大小(0.336~0.503毫米)對於乾燥特性的影響。在此研究中,廢水污泥加入大粒子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。經由入口及出口氣體濕度隨時間的記錄來計算污泥含水量及其乾燥速率。實驗結果發現，最大乾燥速率值會隨著表面速度、進氣溫度、床體溫度、玻璃珠和污泥重量比的增加而增加,但是卻隨著污泥粒子大小的增加而減少。並且提出用以預測最大乾燥速率值之經驗式,其估算值與實驗數據的相關係數值為0.95而計算標準差則為0.18。

The drying of sewage sludge from CPT (Chinese Picture Tube Co.) was experimentally studied in a batch fluidized bed. Experiments were carried out in a 90mm I.D., 1.36m in height laboratory-scale fluidized bed to visualize the effects of superficial air velocity (1.18~1.35 Umf), inlet air temperature (30~60oC), bed temperature (50~80oC), initial moisture content of sludge (16.5~42.8%), weight ratio of glass beads to sludge (12~20) and particle sizes of sewage sludge (0.336~0.503 mm) on the drying characteristics. In this study, sewage sludge was fed to a fluidized bed with coarse particles 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 maximum drying rate increases with increasing of superficial air velocity, inlet air temperature, bed temperature, weight ratio of glass beads to sludge but decreases with increasing the particle sizes. The empirical correlation for the maximum drying rate is proposed to fit the experimental data with a correlation coefficient of 0.95 and standard error of estimate of 0.18.

ACKNOWLENDGMENTS…………………………………………iii
ABSTRACT(ENGLISH)………………………………….…………iv
ABSTRACT(CHINESE)……………………………………………..v
LIST OF TABLES……………………………………………………ix
LIST OF FIGURES……….………………………………………….x
CHAPTER 1 INTRODUCTION……………………………………..1
CHAPTER 2 LITERATURE SURVEY……..………………………7
2.1 Drying kinetic……...…….….…………………………7
2.1.1 Drying kinetics for batch operation……….……7
2.1.2 Constant rate period………………………………9
2.1.3 Falling rate period……………………………….10
2.1.4 Drying mechanism for batch operation………..11
2.2 Effect of temperature…………………………………14
2.3 Effect of superficial air velocity…………………….15
2.4 Effect of particle sizes and weight ratio…..….…….16
2.5 Effect of moisture………………………………….…16
CHAPTER 3 EXPERIMENTAL……………..…………………….18
3.1 Apparatus………………………………………………18
3.2 Experimental procedure………………………………21
3.3 Experimental material………………………………..25
3.4 Data arrangement……………………………………..25
CHAPTER 4 RESULTS AND DISCUSSION…………………….27
4.1 Drying rate value of fluidized bed dryer…………..31
4.1.1 Bed temperature effect………………………….31
4.1.2 Inlet air temperature effect……………………..33
4.1.3 Superficial air velocity effect………………….35
4.1.4 Weight ratio effect……………………………….36
4.1.5 Particle sizes effect……………………………..39
4.1.6 Initial moisture effect…………………………..39
4.1.7 Particle distribution of sludge…………………41
4.2 The maximum drying rate of fluidized bed dryer…48
4.2.1 Experimental parameters effect………………..48
4.2.2 Correlation of maximum drying rate, Vd,max….54
CHAPTER 5 CONCLUISIONS……………….…………………..59
NOMENCLATURE…………….…………………………………………61
REFERENCES………………………………………………………63
APPENDIX……………………………………..…………………..66

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