The effect of noncondensable gas on heat transfer in the preheater of the sewage sludge drying system |
| |
Authors: | Young Cheol Park Joeng-Geun Kim Gyoung Tae Jin Sang-Ho Lee Jong-Ho Moon Seung-Yong Lee Sang-Il Choi |
| |
Affiliation: | 155. Korea Institute of Energy Reserch, 152, Gajeong-ro, Yuseong-gu, Daejeon, 305-343, Korea
|
| |
Abstract: | We used a shell-and-tube type preheater to investigate the effect of noncondensable gas on heat transfer. In the preheater of the drying system, heat is exchanged between steam-air mixed gas which is dryer outlet gas and sewage sludge. To evaluate the performances of the preheater, water was first used in the tube-side material instead of sewage sludge and steam-air mixed gas in the shell-side material. The test variables were as follows: mixed gas inlet temperatures range from 95 to 120 °C; inlet air content, m air /m steam from 55 to 83%; tube-side water flow rate from 42 to 62 kg/h. The shell-side heat transfer coefficient varied from 150 to 550W/m2K, which corresponds to the amount of noncondensable gas in the steam-air mixed gas and the overall heat transfer coefficient varied from 60 to 210W/m2K. Using sewage sludge as a tube-side material the overall heat transfer coefficient varied from 60 to 130W/m2K and the outlet temperature of sewage sludge was above 90 °C, which is high enough for reducing energy consumption in the dryer by preheating the sewage sludge. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|