Numerical Simulation Study Of Gas-liquid Two-phase In Hydrothermal Reactor For Oily Sludge

Oily sludge includes a significant quantity of accessible resources,and if it is not properly processed,it can result in resource waste,pollution and other undesirable consequences.Reduction,resource conservation and safe treatment of oily sludge is pressing issue that must be addressed.The hydrothermal treatment method has promising industrial applications in the treatment of oily sludge with high water content.The key to oily sludge dewatering is mixing of steam and oily sludge in hydrothermal reactor.As a result,it is critical to investigate the type of hydrothermal reactor that can efficiently improve the mixing impact of steam and oily sludge.The CFD method was used to simulate the mixing of gas-liquid phase in the hydrothermal reactor,based on a new technology for hydrothermal treatment of oily sludge.Firstly,the air-water medium was used to explore the effects of air inlet structure and volume on the gas hold-up and liquid phase flow field distribution in the reactor.Secondly,using air and oily sludge as the medium,the mixing of gas-liquid phase in the single-paddle and double-paddle reactors was explored,as well as the effects of the oily sludge viscosity and the number of paddles on the gas hold-up and liquid phase flow field distribution.Finally,a mathematical model of a hydrothermal reactor was established with non-stirred structure.Using saturated steam and oily sludge as the medium,the mixing process with non-stirred structure was investigated,and the impacts of steam inlet volume and inlet pipe diameter on the gas hold-up and gas phase velocity distribution were also studied.The simulation results showed that the annular distributor was more beneficial for the gas distribution in the reactor.With the decrease of oily sludge viscosity,the gas-phase distribution became more uniform.Compared with the single-paddle reactor,the oily sludge in the upper part of double-paddle reactor was disturbed better,and the mass transfer effect of gas-liquid mixing was better.In the reactor with non-stirred structure,the increase of air inlet volume was beneficial to reduce the mixing dead zone.The gas hold-up distribution was summarized by changing the inlet diameter.It was discovered that the gas hold-up distribution was better when the diameter of the reactor was 3.5 mm and the number of holes was 8.