الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
 |  | from | 113 |  |  |
| | | from | 113 | | |
Abstract
Carbon dioxide from fossil fuel burning is the major contributor to the greenhouse effect from human activities. Within the many options and actions for mitigation of greenhouse gas emissions, CO2 capture and storage is emerging as a viable option to achieve the very deep cuts in emissions that might be needed in the medium term. One promising means of CO2 capture for fossil fuels based power plants is to use a lime carbonation–calcination cycle. A jetting fountain fluidized bed reactor has been designed, fabricated and installed to carry out the experimental work. It has 105 mm ID and 4000 mm height. Jabal al-Tair limestone has been utilized as bed materials. During the tests a mixture of nitrogen and carbon dioxide, that simulates exhaust gases (15% CO2), is fed through a bed of lime particles. The lime particles are carbonated by capturing CO2. The concentration of CO2 is measured after the bed to estimate the quantities of CO2 that combined with the lime particles. The influences of operating conditions including bed temperature, fluidization velocity, jet air ratio and jet orifice height on the capture efficiency of CO2 have been studied.
The findings of the present work indicate that the jetting fountain fluidized bed is more efficient in carbonation where the CaO conversion rate increases and the time required for full conversion reduces. Applying jetting fountain configuration enhances gas solids contact and improves the interphases mass exchange between bubbles and emulsion. The capture efficiency of CO2 rate was found to improve with bed temperature and fluidization velocity. On the other side, studying the influences of jet gas ratio and jet orifice height demonstrate that there is an intermediate value at which the capture efficiency records an optimal.
The aim of the thesis:
Enhancing Carbonation Process during Carbon Dioxide Capturing Applying Jetting Fountain Fluidized Bed.
The aim of the present work is to apply a novel configuration of fluidized bed, namely, jetting fountain fluidized bed (JFFB) in Carbonation Process during Carbon Dioxide Capturing. JFFB is characterized by excellent gas-solids contact due to creating a jet in the upper part of the bed, establishing a fountain in the freeboard and moderating bubbles size in the main bed.
The present work presents a comparison study between the JFFB and the conventional fluidized when applied to the Carbonation process of CO2 Capture. The influences of operating conditions on the effectiveness of Carbonation process have been explored. The bed temperatures of 550oC, 600 oC, 650 oC, 675 oC and 700 oC have been considered. Fluidization velocity has been tested at three cases 0.4 m/s, 0.8 m/s and 1.2 m/s. In jetting fountain configuration, a part of gases is fed through the jet while the remaining part is fed through the distributor. Jet gases ratio is varied from 0.2 to 0.6. The orifice height of introducing jet gases above the distributor plate is also an important parameter. It is varied from 8 cm to 16 cm. In all tests the static bed height is fixed to 15 cm.