Research On The Resource Recovery And Reduction Of Oily Sludge From Lanzhou Petrochemical Company

At present,the output of oily sludge has reached more than 10,000 tons per year,putting tremendous pressure on environmental protection.Due to the problems of cost,technology,and energy consumption,the industrialization process of existing processing methods has been slow.This project takes the oily sludge of refinery wastewater treatment plant in Lanzhou as the research object,abandoning a single method of treatment,adopts the method of hot water washing combined with thin-layer drying.The research contents are mainly divided into three parts,the physicochemical properties of oily sludge,hot water washing experiment,thin-layer drying experiment and the regression analysis.The physicochemical properties of the oily sludge were tested.The azeotropic distillation,extraction and ignition methods were used to measure the water content,oil content and ash respectively.The results showed that the water content was 76.94%,the volume was large,and the dewatering was difficult.The oil content was 9.42%and ash content was 8.9%.The oxygen bomb calorimeter,elemental analyzer,and thermogravimetric analyzer were used for analysis.The results showed that the thermal value is 2680 kcal/kg,which is of heat recovery value;the types of heavy metals are abundant;the drying and dehydration stage mainly occurs at 10¹10°C,which provides a reference for drying experiments.The hot water washing experiment was conducted on the oily sludge,and the flocculant and demulsifier were selected through stirring experiments.The results showed that when the PFC:PAM=5:1 and the demulsifier was H₂O₂,dehydration and deoiling effect was achieved better.The influence of seven factors,such as solid-liquid ratio,on the washing effect were explored through the method of controlling variables.The best conditions were:the solid-liquid ratio is 1:3,the stirring speed is 300 rpm,PH=4,the temperature is 80°C,the stirring time is 30 min,the centrifuge speed is 3500 rpm,the centrifuge time is 20min.After this condition,the oil resource recovery rate can reached 52.2%.A thin layer drying experiment was carried out to explore the effects of three factors by means of control variables.The results showed that the higher the temperature,the higher the wind speed,the smaller the thickness,and the better the drying.The sample with a thickness of 3mm was used,drying at 120°C with a wind speed of 2.75 m/s for 110 min.When the equilibrium state is reached,the water content is<2%,the volume is significantly reduced,and the powder is ground and has no tackiness.The drying data were analyzed by 1StOpt.The results show that the Karathanos model is most suitable for the drying process,and the corresponding diffusion coefficient and activation energy are calculated.After hot water washing combined with thin-layer drying treatment,oily sludge can achieve resource recovery and reduction.And through regression analysis,drying model is fitted,which can be help to predict the drying process,and provide technical guidance for the industrial treatment.