Mechanism And Experiment Research On Reaction Control Of Extracting Silica From Typical Biomass

Biomass resources are pretty abundant in our country, but a lot of biomass resources are perennial accumulation with taking fertile farmland or situ burning with waste and environmental pollution. The main points of mechanism and experiment research on reaction control of extracting silica from typical biomass are as follows: the reasearch of feasibilit y and economy for extracting silica from biomass, effects of biomass drying and particle combustion reaction control for extracting silica, and experimental research of preparing hydrated silica from biomass activated ash. Various factors for the extraction process of silica are studied, and dynamics characteristics of the extraction of silica from biomass ash are analysied.The major works could be summarized as the following aspects:Four kinds of biomass(rice husk, corn stalks, rice straw and soybean straw) have been fully oxidized by improved Harrion method. Analyzing the morphology, structure, content and other parameters of biomass-silica by FT-IR, SEM and TEM. The results show that rice husk is the most suitable material for extracting silica from its ash.Drying experiments of biomass(rice husk) which is suitable for extracting silica have been carried out for the research of drying characteristics. Establishing drying kinetic model of rice husk, the effective moisture diffus ion coefficient of rice husk sample and other parameters can be obtained by diffus ion equation based on the experimental data, and the corresponding kinetic model can be obtained too. We consider that the combustion process of a dry spherical rice husk particle can be devised into three distinguished stages: preheating, pyrolysis and char combustion. Here, we demonstrate a control model of spherical rice husk particle combustion, and numerical analysis on the combustion model is carried out under different initial condit ions. The predictions are given to compare with experimental data for verifying the validity of this combustion model.Alkaline- heating and precipitation method is used to prepare hydrated silica from biomass activated ash. The effect of different factor for p reparation of hydrated silica has been studied and the optimum conditions for the production of hydrated silica have been obtained. Various indices of hydrated silica product are superior to the standard requirements HG/T3061(2009). Furthermore, the significant of different factor and dynamic characteristics of the extraction process are studied by second-order rate law.The study of biomass drying and validity combustion control model for extraction of silica can provide theoretical foundation for the design, manufacture and operation. Preparing hydrated silica by alkaline- heating and precipitation method and reaction dynamic of the extraction process of silica from biomass activated ash have been studied. This study has been used on industrialize production of hydrated silica from rice husk ash in Wanyuan biomass power plant. This production line can dispose 12000 ton rice husk ash and produce 5000 ton fine quality hydrated silica each year.