Experimental and Modeling Investigation of Heat and Mass Transfers in an Airlift Packed Column Humidifier
Issue:
Volume 10, Issue 5, September 2022
Pages:
89-102
Received:
22 July 2022
Accepted:
25 August 2022
Published:
21 September 2022
DOI:
10.11648/j.ajche.20221005.11
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Abstract: Background: the use of air humidification in order to produce pure water from saline or waste water take more and more importance since it allows to add value to non-pure water. In this case, the aim of this study was to simulate of air humidification. Material Methods: The experimental device used, for the humidification of the air through its contact with water, is a vertical column filled with packing. It works on the principle of an air lift pump. Modeling equations for heat and material transfer between fluids have been established. Results: Established models are verified by experimental results. The humidification of the air is proportional to the operating parameters such as: the initial level of water in the column, the air flow, the temperature of the liquid and the height of contact between fluids. The air temperature and humidity profiles increase as a function of the packing height. Conclusion: Air humidification is effective if heat and mass transfers between fluids are high. The temperature of the liquid water has a greater effect than those of the other operating parameters on the shape of the air temperature and humidity profiles as a function of the height of the column.
Abstract: Background: the use of air humidification in order to produce pure water from saline or waste water take more and more importance since it allows to add value to non-pure water. In this case, the aim of this study was to simulate of air humidification. Material Methods: The experimental device used, for the humidification of the air through its con...
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A Study on Portland Limestone Cement Blended with Animal Bone Ash and Metakaolin
Jarumi Luka,
Tijani Mohammed Isah,
Olubajo Olumide Olu
Issue:
Volume 10, Issue 5, September 2022
Pages:
103-115
Received:
13 October 2022
Accepted:
7 November 2022
Published:
22 November 2022
DOI:
10.11648/j.ajche.20221005.12
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Abstract: The increased discriminate disposal of agricultural wastes from slaughter houses has become a serious concern resulting in contamination of human environment, thus there is a need to consider utilizing such waste to solve the challenges faced in the production of cement. This study examines the impact of cement replacement with Animal Bone Ash (ABA) and Metakaolin (MK) up to 12.5 wt.% on the physical and mechanical properties of blended cement. The consistence, setting times and soundness test were conducted on thirty-six ABA- MK-cement pastes via Vicat and Le Chatelier apparatus respectively while the mortar strength tests were conducted using a compression testing machine at 3, 7, 28, 60 and 90 days. The chemical analysis for MK revealed that the sum of oxides of silicon, aluminum and iron content was greater than 70% (97.06 wt.%) and thus, a good pozzolan according to ASTMC 618 whereas ABA was less than 70%, but could be regarded as a cementitious filler/additive. Results revealed ABA comprising mainly lime (53.86 wt.%) and Phosphate (40.96 wt.%) from X-ray analyses which agreed with X-ray diffractogram and scanning electron microscopy analyses. Results indicated a slightly higher water consistency between 32 to 36%; a higher volume expansion (unsoundness) between 0.5 – 5 mm whereas the accelerated initial setting time (260 to 126 mins) and retarded final setting time (183 to 315 mins) as the cement replacement was gradually increased. An increase in the blending ratio led to a slightly higher water consistency between 32 – 36%; increment in the volume expansion from 0.5 – 5 mm and lower setting times. Most of the cement blends exhibited enhanced 28 days mortar strengths in comparison with control despite diminution of clinker content due to pozzolanic activity. An increase in strength gain for all cement blends and control were experienced as the curing days were extended despite clinker diminution. The highest strength gain for various testing days and comparison with control: 28.33 N/mm2 (106.5%), 32.42 N/mm2 (109.9), 36.88 N/mm2 (122.61), 41.31 N/mm2 (120.37) and 50.91 N/mm2 (122.35%) respectively.
Abstract: The increased discriminate disposal of agricultural wastes from slaughter houses has become a serious concern resulting in contamination of human environment, thus there is a need to consider utilizing such waste to solve the challenges faced in the production of cement. This study examines the impact of cement replacement with Animal Bone Ash (ABA...
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