The change in pyrolysis parameters has a significant effect on the pyrolysis reaction of oil sludge. According to the research and analysis, the parameters that have a great influence on the pyrolysis process of oil sludge are pyrolysis temperature and pyrolysis time, while other parameters such as heating rate, residence time of pyrolysis gas, type of sludge, particle size, heat The type of solution furnace and whether there are other additives will also have a certain impact on the pyrolysis reaction of oil sludge.
(1) Effect of pyrolysis temperature on pyrolysis characteristics of oil sludge
The pyrolysis reaction temperature is the most critical parameter in the pyrolysis process of oil sludge. The pyrolysis experiment of oil sludge is carried out under different pyrolysis conditions to investigate the effects of different factors on the pyrolysis of oil sludge. The results show that : Thermal cracking temperature > Other factors. From the kinetic point of view, the temperature mainly affects the activation energy of the reaction, and then changes the chemical reaction rate. From the thermodynamic point of view, the temperature affects the change of the Gibbs free energy in the reaction process, which in turn affects the direction of the reaction, and finally determines the product. Composition the pyrolysis temperature of oil sludge will affect the yield and oil and gas quality of the three-phase product produced by pyrolysis of oil sludge. In order to cause thermal cracking and thermal condensation reaction of hydrocarbon organic matter and non-hydrocarbon organic matter in oil sludge, it must be provided sufficient energy, when the pyrolysis temperature is too low, the organic matter in the oil sludge will not get enough energy to generate sufficient thermal cracking reaction, which will cause the pyrolysis residue to reach the discharge standard; when the pyrolysis temperature is too high, not only will it Increasing the energy consumption and the oil resources generated by the cracking will also cause a secondary cracking reaction and increase the gas production.
(2) Effect of heating rate on pyrolysis characteristics of oil sludge
By selecting petroleum refinery oil to explore the effects of different heating rates on pyrolysis experiments, studies have shown that as the heating rate increases, more liquid components undergo secondary cracking at higher heating rates, resulting in the liquid phase yield is lower and the gas production is significantly increased. The effect of pyrolysis rate on pyrolysis characteristics was investigated under high temperature conditions. The experimental results show that the pyrolysis rate has little effect on pyrolysis, and the effect becomes smaller as the temperature increases, but it has a great influence on the gas production. Through the study of different heating methods, it was found that the liquid phase yield under rapid heating was lower than that in the slow heating mode, and it was found that the difference in heating mode had an effect on the gas phase, but there was almost no solid phase yield. The effect is mainly due to the secondary cracking of hydrocarbons. Most scholars believe that when pyrolysis is carried out at a relatively slow pyrolysis rate, the residence time of the pyrolysis oil in a relatively hot pyrolysis temperature environment becomes longer, so that the thermal pyrolysis oil undergoes secondary thermal cracking to form small molecules. The gaseous product results in a decrease in the yield of the oil sludge pyrolysis oil phase product.
(3) Effect of pyrolysis time on pyrolysis characteristics of oil sludge
The pyrolysis reaction time generally refers to the residence time of the pyrolysis reaction of the oil sludge in the reaction equipment under high temperature conditions, and the length of the reaction is affected by a series of parameters such as the characteristics of the sludge itself, the particle size of the material, and the reaction temperature. Insufficient reaction time may result in the residue still not meeting the discharge standard after treatment, and the reaction time is too long, which will increase the energy consumption and increase the treatment cost. The pyrolysis reaction time of oil sludge was determined as 30min, 40min, 50min, 60min, 70min, 80min respectively. The experimental results showed that the conversion rate increased with time before 60min, and the conversion rate remained stable after 60min. The waste plastic was selected as the research material of pyrolysis, and the influence of pyrolysis reaction time on the yield of pyrolysis oil produced by oil sludge was investigated. The reaction time was set from 0 to 120 min. The experimental results showed that the pyrolysis reaction time of oil sludge was 30 min. The pyrolysis reaction has almost been completed. The influence of the pyrolysis reaction time of the oil sludge on the thermal cracking reaction depends mainly on whether the pyrolysis reaction of the material is completed. As the reaction time of the material is prolonged, the yield of the liquid phase product is gradually increased, but when the reaction time exceeds a certain value, the reaction is almost completed, and the yield is no longer increased.
The gas phase generated by pyrolysis in a high temperature atmosphere may affect the progress of the secondary cracking reaction due to the difference in residence time, thereby affecting the liquid and gas production rate. The oil sludge was selected for research. It was found that the residence time of the pyrolysis gas affected the yield of the liquid phase product. The yield was the highest at 525 ° C and 1.5 s, which was 30% of the total weight. The difference in carrier gas permeation rate during the pyrolysis reaction of oil sludge will affect the gas residence time and thus the yield of the gas phase product.
(4) Effect of different types of oil sludge on pyrolysis characteristics
The pyrolysis characteristics of different types of oil sludge vary greatly. The oil sludge from different oil fields is selected as the research object. The research shows that the gas-liquid fraction yield of oil sludge is related to the volatility in sludge, and it is highly volatile. The pyrolysis of the oil sludge is obvious, while the oil content of the low-volume oil sludge is lower, and the residue content is higher. This is because the pyrolysis process of the oil sludge is the volatile component. The process of thermal volatilization and thermal conversion. The higher the volatile content, the higher the gas-liquid yield; the lower the volatile content, the higher the solid phase yield. Pyrolysis experiments were carried out on different types of oil sludges. Under the same pyrolysis conditions, the pyrolysis products of the two types of oil sludges were different, and the liquid phase yield of the oil sludge with high ash content was higher than that of volatiles. Liquid phase yield of oil sludge. According to the above research, the yield of the three-phase product is closely related to the original oil sludge itself. Different types of oil sludge, in which the three-phase components and the content of ash and volatile matter are different, these will affect the pyrolysis reaction of oil sludge and the product.
