Research On Preparation Of Catalytic Oxide For Mercury And Mechanism Of The Oxidation

Emission of flue gas has done great harm to the environment: green house effect, acid rain and metal pollution. Trace metal pollution destroys people's health, especially the mercury. It causes fatal damage to mental system. It is urgent to control the mercury emission of coal-fired power plants, which causes the main mercury polluting. Several technologies are considered for reducing mercury from coal combustion flue gases.Adsorption is the most promising technology for mercury removing from coal-fired boilers. However, its use is limited because of its high cost, poor capacity, low applicable temperature range, regeneration and slow adsorption rate. Attention on cost reduction and high mercury removal efficiency should be paid on in the future research and development.This article is aimed to find an abundant, cheap and high efficient catalyst to control mercury emission from coal combustion.First, the physical and chemical properties of mercury are analyzed. Under the principle of catalytical oxidation reaction, the thought of design and project of the catalysts had been brought forward. six sorbents (V₂O₅/TiO₂ ; WO₃/TiO₂ ; V₂O₅/SiO₂ ;V₂O₅/TiO₂-SiO₂;WO₃/TiO₂-SiO₂;V₂O₅-WO₃/TiO₂) were prepared by Sol-gel method and impregnation. The XRD curve of the samples were obtained on XRD Instrument, a type of software named "Philips X'pert Highscore" was employed to analyze the results. The method of Infrared Ray(IR) detection was utilized as comparation with others.Surface area and pore structure were acquired on the Surface Area and Pore Size Determination Instrument. By determining the adsorption process and quantity of N2 on catalysts in the pressure range of saturated gas, pore volume and pore area of the sample were calculated, according to the theory of BET and BJH, under the temperature of liquid nitrogen. Isothermal nitrogen adsorption experiments were carried out at the same time. Relationship between pore volume, pore surface area and pore types was discussed, so was their influence on adsorption ability of the catalysts. We have investigated various disciplines of the form variety of mercury from simulated flue gas by testing the prepared catalysts on an experiment platform of mercury catalytical oxidation. The effect of temperature, ammonia concentration and various catalysts was discussed, either. In the end, we evaluated performances of adsorption of the catalysts, filtered samples with comparatively better catalytic and adsorptive function.At last, WO₃/TiO₂ and V₂O₅-WO₃/TiO₂ own the best performance of removing mercury among six patterns. They are novel adsorbents of high efficiency and low cost for mercury removing.