Research Of Thermochemistry Kinetics On Mercury Adsorption With Original And Modified Fly Ash

As the main primary energy of China, coal is widely used.Serious pollution problems and mercury releases comes with the burning of coal, which have attracted the attention from the world. Compared with aboard, the study on the mereuryreleasescontrolin coal power plants, Domes tic research is just in the primary stage, the pollutants are discharged without handling. Therefore, it is important to strengthen the systematic research on the primary mercury releasecontrol during the process of coal burning, both forthe implementationof the sustainable development strategy and the protection of human environment.To study the mercury absorption process of fly ash and modified fly ash and to exploit efficient adsorbent, the writer raises adsorption rate and equilibrium absorption capacity as two prime referential parameters, which are based on the evaluation of mercury absorption process of fly ash and modified fly ashby the using designed fixed bed absorption plant.At present, there’s not too much study onmercury absorption process of fly ash fromthe view of dynamics in domestic, while undoubtedly it is of high importance to analyze based on dynamics.It is found in the thesisthat the adsorption process is more in line with the pseudo-first-orderabsorption model according to the fitwith two selected dynamical model. A further analysis reliedon Langmuir isothermal absorptive theory gives a strong prove to the experimental results, then the mercury absorption balancing characteristic curve at different temperature can be obtained. The comparison of the change of absorption isotherm at different temperature shows that the mercury absorption of fly ash possibly is a exothermic process along with the decrease of enthalpy and that when the temperature rises, it may reduce the mercury concentration of the fly ash in the condition ofadsorption equilibrium.When the study is carried on about the impacts of stimulation mercury concentration on absorption process, it is found that the increase of the inlet mercury concentration, which means the improve of the contact odds of the mercury and fly ash, improves the absorption rate and amount due to a positive effect on the absorption process.Temperature, as one of the most important experimental parameters plays a key role in the absorption process. For the original fly ash, the experimental results indicates that the absorption capability decreases as the adsorption temperature increases, which maybe resulted from the which is inhabited with temperature increasing. But for the modified fly ash, the mercury absorption capability increases with increasing temperature Thus, it is a better choice for power plant to set modified ash sprayed before dust removal.Exploiting efficient adsorbent, as one of the main purposes of the thesis, can be reached in the way of improving the mercury absorption properties of fly ashes by surfacechemical modifying. The quantity and quality of active sites on the fly ash are the main influencing factors in the mercury absorption process and they can be obviously changed via chemical modification. Experiments reveal that the HBr modified fly ash enhance better in absorption properties in the adsorption process.