| The energy structure optimization and strategic development directions of China have already been pointed out in the 13 th 5-Year Plane. Now, the current situation of China is in the period of strategic opportunities of optimizing energy structure, and its purpose is to build a green, safe, diverse, intelligent, clean and efficient energy system. With the smooth running of China's economic transition, the concept of globalization gradually interiorize, and the mercury pollution which comes from the coal combustion has become an urgent environmental issue. From the point of control methods of mercury emissions, there is still a large optimization space no matter from the aspects of economy or environmental benefits. In the present work, on the basis of coal combustion emission control, raw materials prices, production cost and industrial application, the suitable and cheap silicate raw material was selected, and the porous nano-sorbent was employed by using sol-gel method preparation to deal with major national needs of energy conservation and emissions reduction. The synthesis method was carried on the preliminary discussion through physical and chemical properties characterization methods, and the samples with high specific surface area and prosperous structure were obtained through appropriate, stable and synthesis methods. According to a series of mercury removal experiments, the performance index and mercury removal mechanism of sorbent were analyzed to obtain a cheap, amorphous carbon and high performance mercury sorbent. Additionally, it could provide the reference in pilot tests and power plant pratical applications.Firstly, a novel silicate mineral sorbent was developed through the sol-gel method. Results indicated that under some preparation conditions, it could be obtained a larger specific surface area(514.2 m2/g) and a more developed pore structure. The appropriate ratio of alcohol/acid could not only avoid inhibition to the hydrolysis reaction, but also make the solution more even. The increase of reaction temperature was benefit to the hydrolysis reaction, but too high temperature would affect the quantity of colloid. With the increase of calcination temperature, the speed of crystal formation increased, but too high temperature made the grain deformation and uneven grain size, resulting in the specific surface area smaller. Through scanning electron microscope(SEM), and it demonstrated that the characterization of sorbent was porous structure and its pore size distribution was uniform. Additionally, it had a complete crystal structure. Compared with sorbent loading KBr or not, there was no obvious change in macro structure, and it was still porous.The mercury removal characteristics of novel sorbent were investigated through mercury removal tests, to understand its main influencing factors and reaction mechanisms. Results indicated that under the same condition, as the quantity of load was increased, the chemical adsorption ability of sorbent was improved. As the absorption temperature was risen, the chemical adsorption ability was promoted, while its physical adsorption ability was restrained. There was a turning point temperature between 90 and 120?. With the increase of initial concentration of mercury, the mercury removal efficiency decreased, while the adsorption quantity of mercury increased, and there was an optimal value between sorbent dosage and initial concentration of mercury. A larger specific surface area and a large number of large pore structures were benefit to adsorb mercury. A series of chemical reactions between halogen elements and mercury which was taken place at the external surface of sorbent and its internal holes, improved the chemical adsorption capacity of sorbent. And results showed that under same conditions, the mercury removal efficiency was improved significantly by adopting the modification of halogen sorbent, and the maximum mercury removal efficiency in simulated flue gas and real furnace flue gas was 90% and 80%, respectively. |
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