Adsorption characteristics of various adsorbent-adsorbate pairs

• Main Author: Soo, Jun Hao
• Other Authors: Anutosh Chakraborty
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/75110
• Institution: Nanyang Technological University

In recent years, global warming has become a serious threat to our planet due to the emission of carbon dioxide generated from burning of fossil fuels such as oil, natural gas and coal to meet the high demand for energy. Hence, adsorption chiller has become the alternative to replace the current vapour compression system to minimise the ozone depletion and global warming potentials. In comparison of adsorption assisted and vapour compression system, the advantage of adsorption assisted system has no coolant pollution, simplifies system control, enables low cost production and reduces noise pollution. To increase the efficiency and reduce the size of adsorption assisted system, the improvement of water adsorption with fast kinetics is essential. Hence, this report shows on improvised AQSOA-Z05 zeolite + water interaction by impregnate calcium chloride (CaCl2) ion to the zeolite material and form a composite adsorbent. The modified AQSOA-Z05 undergoes a gravimetric uptake water adsorption experiment at temperature of 25 ˚C, 30 ˚C, 40 ˚C, 50 ˚C and 60 ˚C with the relative humidity that varying from Henry’s region up to 90% under static and dynamics condition. N2 adsorption experiment is conducted to determine the surface and porous characteristics of the adsorbent materials. Next, the experimental datas are fitted with various isotherm model to understand the thermodynamics properties between the zeolite + water interaction. The adsorption kinetics data are fitted with modified Langmuir kinetics equation under dynamics condition to evaluate the time needed for the interaction to achieve steady-state. The results show at 25 ˚C, 30wt.% CaCl2 solution re-impregnated in AQSOA-Z05 perform approximately 3.7 times better in terms of adsorption uptake and shorter hydrophobic length as compared to the conventional AQSOA-Z05. However, the 30wt.% CaCl2 solution re-impregnated in AQSOA-Z05 takes approximately 3 times of the adsorption rate as compared to conventional AQSOA-Z05. Hence, CaCl2 in AQSOA-Z05 adsorbents are potentially suitable for designing chiller, which could be derives at the heat source temperature of 60˚C or lower.