Fenton Combined Hydrothermal Carbonization For Sludge Volume Reduction And Quality Improvement

With the improvement of China’s urbanization and industrialization,the burden of sludge treatment is becoming increasingly serious.Aiming at the problems of huge sludge production,complex composition,high water content,and difficult removal in China,this paper applies Fenton’s reagent combined with hydrothermal carbonization to sludge treatment.Firstly,the influencing factors that influence the capacity reduction of hydrothermal carbonization reaction system were explored.Secondly,the influencing factors that influence the upgrading ability of hydrothermal carbonization reaction system were explored.Finally,the combustion performance of hydrothermal charcoal prepared by hydrothermal carbonization is studied,the most suitable hydrothermal conditions for combustion are selected,and the combustion process is designed and calculated.First,using sludge as a raw material,the effects of reaction temperature,residence time,and introduction of Fenton reagent on the volume reduction effect of sludge system were studied.Aiming at the effect of the single component of Fenton reagent on the volume reduction of the reaction system and the optimal dosage of the sludge reagent of the reaction system;finally,according to the previously explored reaction properties and reaction reagent measurement,the best suitable Fenton bound water Reaction conditions for thermal carbonization.Combining Fenton’s reagent with hydrothermal carbonization can achieve a more ideal volume reduction effect than the two alone.Under the same conditions,the introduction of Fenton reagent increased the volume reduction rate of hydrothermal charcoal from 31.03% to 41,07%.After investigation,the optimal dosage of Fenton reagent combined with hydrothermal charcoal was 1.25 g hydrogen peroxide / 20 g dry sludge And 0.42 g of ferrous chloride/ 20 g of dry sludge.The optimal reaction conditions were 160 ℃ and 1 hour.At this time,the system achieved a capacity reduction rate of 40.7%.Secondly,the influence of different factors on the quality of hydrothermal system was studied.Prolonging the hydrothermal time and increasing the hydrothermal temperature can improve the quality of hydrothermal system.Different heavy metals have their own suitable p H environment,and the differences are obvious.For the treatment of complex systems,the optimal option at p H = 7.The combination of biomass and sludge can achieve excellent quality improvement effect under the action of Fenton’s reagent.The results show that the sludge and wood chips are cohydrothermally heated at a ratio of 1: 3.The project modified sludge-wood shavings hydrothermal charcoal with the best quality improvement effect to produce modified hydrothermal charcoal.The adsorption kinetics of Pb on unmodified and modified hydrothermal carbon was studied.The project concluded that the adsorption of Pb by hydrothermal charcoals conforms to a pseudo-secondary kinetic process,and that compared with modified hydrothermal charcoal(Q = 22.13 mg / g),the modified hydrothermal charcoal has a higher adsorption capacity(Q = 49.36 mg / g).Finally,the application of hydrothermal carbonization product-hydrothermal charcoal as fuel is studied.Sludge and its thermal char products are considered unsuitable as fuel because of their high ash content and low calorific value.The mixing of biomass can complement the shortcomings of sludge-based hydrothermal charcoal.After co-heating with wood chips,the carbon content of hydrothermal charcoal increased from 20.32% to 50.32%;its dry basis calorific value increased from 9.29MJ/ kg to 20.9MJ / kg.From the point of ignition,sludge and hydrothermal charcoal have a low ignition point,which makes such substances easy to burn,but is not suitable for long-distance transportation.The process of sludge-based hydrothermal charcoal for combustion was integrated,and mass balance and energy balance were calculated.This process can significantly improve the utilization rate of sludge resources.Processing 1ton of sludge can produce 224.85 kg of hydrothermal charcoal which can be used as fuel.The combustion of this part of fuel can release 4698.74 MJ of energy.