Modified Effectiveness Model for Crossflow Packed-Bed Humidifiers

2019 ◽  
Vol 5 (1) ◽  
pp. 27-33
Author(s):  
Mostafa Sharqawy ◽  
◽  
Robert Zinni
Author(s):  
Hassan Pahlavanzadeh ◽  
Parisa Nooriasl

Desiccant evaporation cooling technology is compatible with the environment and can be used as an air conditioner in the indoor environment of the buildings. The characteristics of dehumidification column of the liquid desiccant evaporation cooling air conditioning system (LDCS) are introduced in this paper. This system was designed and manufactured for this purpose. Lithium chloride (LiCl), as liquid desiccant, and a packed bed column were used for the dehumidification. The described system includes a part for processed air simulation in various temperatures, humidities, and flow rates. The effectiveness model, based on heat and mass transfer equations, is considered for predicting performance of the lithium chloride dehumidification system. For validation purpose, a comparison was performed between experimental outlet data of the system and the corresponding results of the experimental model that showed a satisfactory correlation i.e., increase in the mass transfer unit number (NTU) leads to a better performance of the dehumidification system. In addition, factors leading to increase in NTUs are also investigated.


TAPPI Journal ◽  
2016 ◽  
Vol 15 (4) ◽  
pp. 265-272 ◽  
Author(s):  
ROHAN BANDEKAR ◽  
JIM FREDERICK ◽  
JAROSLAV STAVIK

This study addresses the challenges a dissolving-grade pulp mill in Canada faced in 2014 in meeting its total reduced sulfur (TRS) gas emission limit. These emissions from the recovery boiler exit are controlled by passing the boiler exit gas through a TRS scrubber system. The mill employs a cyclonic direct contact evaporator to concentrate black liquor to firing solids content. The off-gases from the direct contact evaporator flow to the effluent gas control system that consists of a venturi scrubber, a packed bed scrubber, and a heat recovery unit. Emissions of TRS greater than the regulated limit of 15 ppm were observed for a 4-month period in 2014. The level of emissions measured during this period was significantly higher than about 12 ppm, the expected average value based on historic experience. The problem persisted from mid-June 2014 until the annual mill shutdown in October 2014. The main TRS components detected and the performance of the Teller scrubber in capturing them are examined. Other potential causes for these emissions are identified, including mechanical problems such as broken packing in the TRS packed bed scrubber, broken baffle plates in the scrubber, and cyclone evaporator leaks causing air ingress. Repairs were carried out during the mill shutdown, which eliminated the TRS emissions problem.


2015 ◽  
Vol 135 (7) ◽  
pp. 435-436 ◽  
Author(s):  
Kazuhiro Takahashi ◽  
Kohki Satoh ◽  
Hidenori Itoh ◽  
ichi Itakura

2018 ◽  
Author(s):  
Bassem Hallak ◽  
N. Linn ◽  
Eckehard Specht ◽  
Fabian Herz

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