Preparation Of Sandwich Ash Ceremsites And Application Research In Biofilter For Nitric Oxide Denitrification

Utilizing fly ash as raw material to prepared the sandwich ash ceramisites and its application to the study of purifying the simulated nitric-oxide-containing waste gas, not only can reduce the excessive accumulation of fly ash effects on the environment but can make the industrial air pollution situation caused by exhaust emissions be improved.In the experiment of preparation of sandwich ash ceramisites, we could acquire unburned's sandwich ash ceramisites of large specific surface area, high porosity, high intensity, with fly ash, cement as the main raw material, plastic foam particles as the core, lime and plaster as activator, water glass as adhesives, FeCl₃·6H₂O as surface modification agent, mixed with light materials, through mixing, molding, natural curing process. Effect of binder content, activator content, surface modification agent content on the characters of sandwich ash ceramisites were found through experiment.Through experiments, the rational ration of fly ash, cement and other materials and conditions were confirmed. Process recipe was: the fly ash 75%, cement 10%, activator 8%, light materials 7%, in addition, each l00g raw with water 35ml, the modification reagent 5ml of concentration 2mol/l, sodium silicate about 10g; performance of the sandwich ash ceramisite was tested and analyzed. The results showed: specific surface area 4.12m2/g, porosity 52.5%, anti-static strength 3.87kg; Appearance and scanning electron microscopy showed that sandwich ash ceramisites diameter of 5⁸mm, rough surface, the internal porosity developed.The sandwich ash ceramisites were applied in the biofilter with biofilm carrier. Scanning electron microscopy showed that: sandwich ash ceramisites were attached by a large number of micro-organisms on the surface and in the interior. The simulated nitric-oxide-containing waste gas was purified by denitrfication. The influences of operation parameters such as carbon sources, gas flow, inlet nitric-oxide-containing concentration, the flux of drenching liquid and inlet O2 concentration were studied. The results showed that: benzyl alcohol was more suitable as the carbon resources to remove nitric-oxide-containing by denitrification than alcohol and glucose; The less gas flow enters into the biofilter and the lower inlet nitric-oxide-containing concentration, the higher the removal efficiency would be gained; In the experimental parameter range, the flux of drenching liquid almost had no effect on the performance of biofilter; To get higher removal efficiency, the inlet oxygen concentration must be less than 6%. When the air flow rate Q=0.2m³/h, spray volume L=10ml/min, the inlet concentration of NO is stabilized at 400mg/m³, oxygen volume content is 4% or less, purification efficiency of the biotrickling filter was 82% or more.