الفهرس 
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Abstract
Recently, natural gas (NG) has been considered an attractive alternative of conventional fuels as it is cheaper and has less carbon dioxide and other pollutants emissions making it more suitable environmentally wise. Methane (CH4) is the main constituent of natural as it presents about 70-90 % of the total mixture. Storing natural gas (NG) is one of the central challenges that hinder its utilization in a wide range. Natural gas is commonly stored in a compressed form (CNG) or in a liquefied state (LNG). Compressed natural gas requires compressing natural gas to less than 1% of its volume at standard conditions. CNG cylinders are usually under high pressures of about 20 - 25 MPa. On the other hand, LNG requires a pressure of about 1-2 MPa and a temperature of about -162° C. Therefore, it requires very special and expensive equipment. A promising new alternative for storing natural gas under relatively low and mild pressures (less than 4 MPA) is adsorption storage, which is based on the principle of storing natural gas molecules on the surface of a porous adsorbent with a large surface area such as activated carbons. Due to relatively low working pressure, ANG tanks have a number of advantages over CNG and LNG tanks such as light weight, cheaper materials, safer operation environment and lower overall cost The Research Problem : Experimental investigation of the dynamic characteristics of adsorbed natural gas (ANG) storage during charging and discharging process. And the research aims : Unlike most previous studies which dealt with a pure single component (Methane), the commercially available Egyptian natural gas is used. Results are analyzed considering natural gas as ; (i) pure methane, (ii) ideal gas mixture and (iii) real gas mixture. The study also investigates the effect of internal cooling of the ANG tank during charging on the performance of the system. Moreover, the study aims to develop a model for predicting the kinetics during the charging process accurately for the adsorbent/adsorbate pair. Steps of study : Experiments have been carried out using a natural gas storage tank packed with 1009 ± 1 g of Granular Activated Carbon (GAC) commercially known as Cell Carb GM100. The storage tank has been supported with an internal gas distributer and a cooling coil heat exchanger. The function of the gas distributer is to expedite and improve the flow of natural gas through the packed adsorbent, whilst the cooling coil heat exchanger is used to cool down the adsorption bed during charging process. Measurements have been conducted within temperatures ranging from 30 to 50 ºC and pressures up to 10 bar using the volumetric technique. Temperature distribution through the ANG tank and pressure profile of the load cell during charging and discharging processes have been presented. The instantaneous adsorption uptake is also estimated. charging process has been carried out with and without internal cooling of the ANG tank. Adsorption kinetics have been investigated using two models namely ; (i) the well-known linear driving force model (LDF) and (ii) a modified version of LDF model proposed in another study. The study concludes : Based on the present study and obtained results, the following conclusions may be drawn; (i) Temperature of adsorption bed increases sharply at the early stages of adsorption process, it then decreases gradually until reaching the equilibrium condition. (ii) The instantaneous adsorption uptake predicted considering natural gas as an ideal gas mixture is consistent with that predicted considering natural gas as a real gas mixture within the operating conditions of the experiments. (iii) Cooling of ANG tanks during charging process removes the heat of adsorption faster and helps controlling the thermal fluctuations. It also reduces the required time for charging at maximum capacity to about 25 %. (iv) Using LDF model to predict the uptake values may be possible after a passed time but using it at the start of the adsorption process results in high errors. (v) A modified version of the LDF model has been developed which can predict the adsorption uptake kinetics from the start to the end with high accuracy within the investigated range (30- 50 ºC temperature and 4-10 bar pressure).