Porous catalysts has big advantage in our life, activated carbon is an example of these porous materials. It is used in water and air pollution treatment. The effect of activated carbon depends on several properties such as pore size, diameter, and internal surface area of it. Therefore, it is essential to measure the surface area of activated carbon or any porous material. Hence, in this project a surface area analyzer was designed, it is the first attempt to design such analyzer.
Theory behind the surface area measurements was studied. BET theory is used in designing and testing the apparatus. The analyzer was designed and tested for operation. To insure the safety and ease of use of the analyzer, HAZOP study was applied to the system.
One of the more important things in the design is to create a vacuum system to operate the adsorption-desorption process at constant temperature. Liquid Nitrogen is used as coolant because adsorption process requires very low temperature. Eleven experiments of experiments were conducted to measure surface area of varies types of adsorbents. Silica jel adsorbent of known surface area was used to calibrate the analyzer, after that many types of activated carbon was tested for its surface area.
Commercial activated carbon was tested 3 times with different time of preparation (0.5, 1 and 2) hrs and the results are (1279, 1672 and 1182) m2/g respectively. The other activated carbon that produced from olive stone in the university with different types of preparation, 5 types was tested and the resulting surface area are (610, 675, 926, 3790 and 2335) m2/g.
Surface area measured were in line with literature values, therefore, the designed analyzer work well, but still needs a little modification (such as use a digital measurements for pressure) to make the result more accurate.