Preparation Of Biomass Fuel By Chinese Medicine Residue Combined With Sewage Sludge

Since the 21st century,the amount of urban sewage treatment in China has been increasing,resulting in a large amount of sludge,which,if not handled properly,will cause serious harm to the environment and humans.The sludge incineration method is a simple and effective sludge treatment method,which can maximize the safe and harmless disposal of sludge.In addition,China is a big country in the production of traditional Chinese medicine,and the Chinese medicine residue,a by-product of the Chinese medicine production process,needs to be properly disposed of.Due to the high moisture content of sludge in China,it is necessary to further dry the sludge when it is incinerated,which increases the time cost and economic cost.Therefore,this paper studies the feasibility of using traditional Chinese medicine slag as raw material to prepare biochar as skeleton particle by slow pyrolysis method to improve the dewatering performance and combustion performance of municipal sludge.Firstly,a series of biochar was prepared by orthogonal test method under different pyrolysis temperature,heating rate and retention time,and its basic physical and chemical properties and structural characteristics were systematically analyzed.The results showed that the yield of biochar decreased with the increase of heating rate,pyrolysis temperature and retention time;the fixed carbon content of biochar gradually increased;the calorific value increased first and then decreased;the pyrolysis temperature on the shape of biochar The appearance and pore structure characteristics have an important influence.As the pyrolysis temperature increases,the pore structure expands continuously,the pore walls become thinner and the surface gradually flattens.The main factors affecting the quenching and tempering of municipal sludge by mechanical vacuum dewatering were studied by vacuum suction filtration.The moisture content and specific resistance of sludge filter cake were used to illustrate the dewatering effect of biochar on sludge.Surface electron microscopy and other methods reveal the mechanism of biochar on the dewatering of municipal sludge.The results show that when the pyrolysis temperature is 500°C,the biochar particle size is 75～150μm,and the addition amount is 3g/100ml sludge,the biochar has the best dewatering effect on municipal sludge,and the sludge filter cake moisture content is from the original.The sludge volume decreased from 81.10%to 68.71%,and the sludge specific resistance decreased from 1.42×10¹³m/kg to4.19×10¹²m/kg.It shows that biochar has a significant improvement on the dewatering performance of municipal sludge,which provides conditions for sludge incineration.The combustion characteristics of biochar,municipal sludge and dewatered mixed filter cake were analyzed by thermogravimetric analysis.The combustion characteristics were studied and the reaction kinetics model was established.The results show that:the biochar ignition temperature is high,the burning speed is fast,the urban sludge has low ignition temperature and the burning rate is slow.The combustion characteristics of the mixed filter cake are generally represented by the interaction of sludge and biochar,and the mixed filter cake.The burning rate is faster than that of a single sludge,and as the proportion of biochar added to the sludge increases,the calorific value and combustion performance are gradually enhanced.The comprehensive combustion performance of the mixed filter cake was significantly improved,indicating that the biochar can effectively improve the combustion performance of the sludge.