Experimental Study On Co-pyrolysis Of Solid Waste Incineration Fly Ash And Biomass To Prepare Activated Carbon

Waste incineration fly ash production is huge in China,but the widely used treatment methods are traditional with problems such as complicated processing and high cost.At the same time,biomass is more and more widely used in the field of activated carbon preparation because of its low cost and wide source.It is known that alkali metals can improve the performance of activated carbon.Therefore,waste incineration fly ash is mixed into biomass raw material and pyrolyzed to prepare activated carbon.It not only realizes the efficient utilization of biomass resources,but also finds a new way for the treatment of fly ash.Activated carbon with strong adsorption performance and stable chemical properties can be prepared by activating and modifying the carbonized products obtained from pyrolysis,which can be used in the fields of cooperative removal of gas pollutants and wastewater purification.The yield and adsorption properties of activated carbon are the main factors to be considered during the preparation.The properties of activated carbon are affected by pore structure and surface functional groups,which in turn depend on the raw materials and preparation conditions.In this paper,poplar bark and waste incineration fly ash were used as raw materials,and water vapour was used as activator to prepare active coke in horizontal high temperature tubular furnace.The effects of mixing ratio of raw materials,carbonization and reaction conditions in activation process on product yield,specific surface area and functional groups on the surface of pore structure were studied.Because there are many research variables,in the carbonization experiment,the carbonization conditions selected for research are raw material ratio and carbonization temperature.In the activation experiment,raw material ratio and activator concentration were selected as activation conditions.By studying the variation trend of yield and specific surface area of carbonized products with the above two factors,the better carbonization temperature and raw material ratio were selected.The experimental results show that the yield of activated coke decreases with the increase of temperature,and the change trend of specific surface area is just the opposite.Because the specific surface area of carbonized products of each group is very low,the carbonization temperature is 300℃ with the highest yield.As far as raw material ratio is concerned,the best carbonization conditions are as follows:the ratio of poplar bark to fly ash is 2:1 and 5:1,and the yield and specific surface area of carbonized products prepared under these two experimental conditions are larger.According to the above two groups of selected carbonization conditions,the activation process was continued,and the effects of activator concentration and raw material ratio on the yield,specific surface area and pore structure of activated coke were investigated.According to the experimental results,the blending ratio of fly ash in raw materials was further reduced,and it was found that when the blending ratio of biomass and fly ash was 10:1,the product had higher yield and better performance.In order to explore the influence of activation atmosphere,the range of 0-25%water vapor concentration was taken as the research scope.It was found that the experimental conditions with better preparation effect were concentrated in 10-20%,indicating that the activation effect will be limited whether the concentration of activator is too large or too small.