| Oily sludge is the main by-product in the process of oil extraction,transportation,refining and storage.Due to the concentration of toxic and harmful substances,such as heavy metals and chemical reagents,the disposal of oily sludge is always a challenging problem.At the same time,due to its rich hydrocarbon and refractory petroleum hydrocarbon resources,oil sludge is considered to be a highly valuable renewable resource,which is important to meet today’s increasingly depleted energy needs.The purpose of this paper is to quantitatively study the degree of influence of certain conditions on the reaction,and establish a systematic and effective data set.The main work contents are as follows:(1)The pyrolysis characteristics of sludge and forest waste(biomass)are studied by industrial analysis,elemental analysis and thermogravimetric method.The interaction between the two is the most intense in the devolatilification stage,and the rate of the reaction increases and the reaction is completed faster.The results of thermodynamic and kinetic calculations show that the reaction activation energy of blends also decreases at the devolatilization stage,and the activation energy of the reaction is lower than that of pure Oily Sludge studied by scholars before,so the pyrolysis reaction is easier to proceed.Fourier infrared spectroscopy,X-ray photoelectron spectroscopy and thermogravimetric-mass spectrometry are used to analyze the migration rules of major pollutant elements N,S and Cl in the two samples and their blends during co-pyrolysis(combustion).It is found that the order of magnitude of N pollutants among the three pollutants is much higher than that of S and Cl pollutants,and most N pollutants are small molecules NH3.(2)The relationship between three phase pyrolysis products and pyrolysis temperature,pyrolysis time and material mixing ratio s studied by pyrolysis experiment and machine learning model.Random forest algorithm shows that pyrolysis time is the most important factor affecting the distribution of three-phase products.Pyrolysis temperature and material mixing ratio have different effects on different products.In addition,the addition of biomass can improve the quality of pyrolysis products and significantly increase the yield of pyrolysis gas.Most of the N substance in the sludge finally enters the pyrolytic oil,which will affect the secondary utilization of pyrolytic oil to a certain extent.The radial basis network has incomparable advantages in training and generalizing the three-phase yield data of pyrolysis.The model not only has low time complexity and space complexity,but also has high prediction efficiency.(3)The combustion process of two samples and their blends under O2/CO2 is studied.The presence of oxygen accelerates the reaction compared with the pyrolysis process,and the peak value of DTG curve increases obviously.On the other hand,CO2,as a greenhouse gas,absorbs excessive heat in the early stage of the reaction,resulting in a delay in the devolatilization stage.In the actual combustion process,the circulating flue gas is high temperature CO2 gas,so this loss can be ignored.The random forest algorithm is used to analyze various factors affecting oxygen-rich combustion.Different from pyrolysis,the influence of temperature is more than 60%,while the increase of oxygen concentration had a great impact on the reaction at first,and then the influence gradually decreased,indicating that dynamic increase of oxygen could be used to reduce energy consumption in the actual process.Finally,the accuracy of the generalized time series model is quite high,and the results of the model training are basically consistent with the experimental results. |
