Studies On Preparation Of Spherical Shaped Cotton Stalk Based、Cow Bone Char And Its Machinery And Mechanical Properties

At present, the Commonly used activated carbon adsorbent at home and abroadwas mainly refers to powdered activated carbon adsorption material. The powderactivated carbon with a low bulk density, Thus there are another inconvenience aboutstore and recycling,Further more it can be easily contaminated dust from by air, andany other shortcomings. But the molding activated carbon adsorbent can beovercoming and covering the drawbacks of powder activated carbon it mentionedabove. And it has convenience on processing, so it is easily processed into the anyshapes needed. So it has widely application range at home and abroad.In this paper, firstly analyzed the main component and confirmed pyrolysischaracteristics of cow bone and raw cotton stalks by thermal and component analysis.And as a raw material, Activated carbon was prepared from cow bone and cotton stalkby chemical activation with potassium hydroxide (KOH) using activator. The specificsurface area is become objective function and optimized the preparation conditions ofbiomass charcoal (affecting factors such as activation temperature, activation time,alkali carbon mass ratio, impregnation time) by orthogonal experiment method.The spherical formed (biochar) activated carbon was prepared using by the bonechar and cotton stalk based carbon respectively prepared at optimized conditionsabove as material, attapulgite clay as a binder (additive) prepared spherical shape(biochar) activated carbon. The mechanical compressive strength is become objectivefunction and optimized the preparation conditions spherical shape biomass charcoal,such as quality of soil carbon ratio, calcination temperature and calcination time byorthogonal experiment and single factor experiment method. And characterized thepore structure and performance by scanning electron microscopy (SEM) analysis,BET analysis and purification of including COD industrial waste water.At the end, the hydrodynamic properties of spherical activated carbons werestudied. And the affecting factors to pressure drop, such as the diameters of activated Carbon particels, the heights and voidages of the fixed bed, and the gas superficialvelocity, were observed. The results showing that the spherical formed activatedcarbon have the best hydrodynamic property and among the affecting factors the bedvoidage has a maximum impact.The optimum preparation conditions for cow bone char and cotton stalk basedcarbon were respectively: the activation temperature800℃, activation time20min,alkali-carbon ratio (g/g)1:1, impregnation time36h; the activation temperature750℃,activation time30min, alkali-carbon ratio (g/g)1:1, impregnation time24h. optainingfrom three parallel validation experiment resuls revealing that the product yields wererespectively:63.36%、63.42%、63.29%；25.88%、24.06%、23.36%.the surface areameasured by methylene blue adsorption methods were respectively:389.3m2/g、411.7m2/g、386.1m2/g；1083.7m2/g、1113.1m2/g、1147.3m2/g.Attapulgite clay content, calcination temperature and calcination time is themain affecting factor on the overall performance of spherical formed activated carbon.Since the attapulgite clay can be more effectively improve the wet molding ability ofspherical formed activated carbon. therefore, increasing with clay content well beincrease the dry strength and it also has a wet strength too. Spherical formed activatedcarbon particles not only used for air purification in ower daily life, but also can beused in wet environments and wastewater treatment. Fully considering the singlefactor test and orthogonal experimental results，when the results were respectively:Soil carbon ratio4:6, calcining temperature380℃, calcining time50min forSpherical formed cow bone char; and soil carbon ratio5:5, calcining temperature380℃, calcination time50min for spherical shaped cutton stalk activated carbon particleshave a good mechanical compressive strength. Under the maximum load the averagevalue of dry and wet strength were respectively:18.9N、12.7N、9.3N、5.7N. Thethree parallel validation experiments resulting that the dry and wet compressivestrength of spherical shaped activated carbon particles were respectively:18.9N、17.7 N、18.1N；5.7N、5.1N、6.3N for Spherical formed cow bone char;13.1N、11.9N、12.7N;8.8N、9.3N、9.8N for spherical shaped cutton stalk activated carbonparticles.It can be known from SEM analysis results, the pore structures of cotton stalkbased carbons are superior than cow bone char. The specific area of cotton stalk basedcarbon before and after spherical forming were respectively:1026.10m2/g、344.13m2/g,And the pore size were focused on mesoporous adsorbents3nm and4nm around. Andit having good adsorption bleaching effect on methylene blue and COD industrialwastewater.Its shown from adsorption purification experiment of COD industrial wastewater.The shaped particles and unshaped powdere are also having purification effects onhigh COD wastewater. The minimum COD value of water sampels after adsorptionprocess by using powdere and shaped particle of cotton stalk based carbon arerespectively102.85mg/L and112.68mg/L.have reached the secondary standard ofnational wastewater discharge. the shaped particles will be failed after using twice,and will be saturated after using5h continuasly.Becoming the characteristic parameters for fixed bed the bed voidage has amaximum impacts on resistant pressure drop at unit packing height of the adsorptioncolumn filler. At the same bed height the size of the particle become larger, the bedvoidage will be larger too, instead of this the pressure drop will be smaller. Therefore,the selecting of larger sized particles as a filler is more reasonable for industry,because of the resistant pressure drop the large sized particles has a great demandingon to the Industrial equipment and it can be cause bad economy.