Study On Preparation Of Bio-Asphalt From Liquefaction Of Municipal Sludge

Municipal sludge is the accompanying product after the treatment of urban residents’domestic sewage.Its output is huge,the components contained are complex,and the content of organic matter is high.If it is improperly disposed of,the toxic substances（such as virus bacteria,parasites,heavy metals,etc.）will cause serious harm to the living environment and health of residents,and at the same time,it is a waste of solid waste resources in disguise.In order to realize the efficient resource utilization of urban sludge and promote the sustainable development of pavement materials,this paper uses urban sludge as raw material to liquefy sludge heavy oil,and prepare bio-asphalt by blending different amounts of sludge heavy oil with 50^#matrix asphalt.Study the blending mechanism of heavy oil and base asphalt,and comprehensively evaluate the road performance of bio-asphalt using three major indicators,anti-aging,adhesion,storage stability and high and low temperature performance.This article first analyzes the physical and chemical characteristics of municipal sludge.On this basis,absolute ethanol is selected as the liquefaction solvent,nitrogen is used as the liquefied protective gas,and the reactor is used as the liquefaction device.The liquefied product prepared is subjected to suction filtration and rotary distillation to obtain sewage.Mud heavy oil.Through orthogonal experiment analysis of the influence of solid-liquid ratio（dry sludge:absolute ethanol）,residence time and reaction temperature on the sludge oil production rate,it is determined that the best preparation process for sludge liquefaction is solid-liquid ratio 1:15,the reaction temperature is 275°C,the residence time is 1 h,and the oil yield is 22.36%.The elemental analyzer,gel permeation chromatograph,thermal analyzer,GC-MS and fourier infrared spectrometer were used to study the elemental composition,molecular weight,thermal stability,functional group structure and chemical composition of sludge heavy oil,and compare it with the difference in petroleum pitch.The results show that most of the C and H elements of the municipal sludge are transferred to the sludge heavy oil during the liquefaction process,and the process mainly reacts to form ester compounds;the element composition,molecular weight and functional group structure of the sludge heavy oil and 70^#matrix asphalt There are differences,but its thermal stability is good.The sludge heavy oil was mixed into 50^#matrix asphalt in a certain proportion to prepare bio-asphalt.The blending mechanism of sludge heavy oil and matrix asphalt was analyzed by fluorescence microscope and fourier infrared spectrometer.Compare the three indexes of bio-asphalt prepared with different amounts of sludge heavy oil and 50^#,70^#and 90^#matrix asphalt;take the mass loss,penetration ratio and residual ductility of the residue after the aging of the film oven as the indexes,research anti-aging properties of bio-asphalt;use water boiling method to evaluate the adhesion of bio-asphalt and aggregate;test the storage stability of bio-asphalt through segregation test and fluorescence analysis;use dynamic shear rheometer to test the rutting of bio-asphalt and base asphalt factor and irrecoverable creep compliance J_nr,compare its high temperature performance;use a curved beam rheometer to test the creep stiffness S and creep rate m of bio-asphalt and base asphalt to compare their low-temperature performance.The results show that when the sludge heavy oil content is 5%to 10%and 15%to 20%,the three major indicators of bio-asphalt meet the requirements of the 70^#and 90^#asphalt specifications;when the sludge heavy oil content is 5%to 20%%,bio-asphalt has good anti-aging properties,adhesion properties,storage stability and low-temperature performance,but the anti-rutting performance of bio-asphalt decreases with the increase of sludge heavy oil content,so its content should not be too high.The suitable dosage range is 5%to 10%.