Basic Research On Reducing Heavy Oil Viscosity By Cavitation Technology

As a novel technology,cavitation technique has good prospects for development because of its own unique advantages.This dissertation aims to study hydraulic cavitation and ultrasonic cavitation on reducing heavy oil viscosity and main research contents are as follows:1.Different crude oils under different storage conditions,its properties like volatility may change greatly through preliminary research on different crude oils.Designed and set up oil and gas balance experimental device,determining distillation range,releasing gas volume and its compositions of Venezuelan crude oil,Bo Hai oil and Russian crude oil,in order to ensure safe storage of crude oil in oil tank.Finally,safe storage suggestions are proposed according to the results.Experimental results show that releasing gas volume from per 100 mL crude oil not only has high value but also proportion of C3+C4 is above 50% when paraffinic crude oil and gas are in balance.We suggest monitor releasing gas proportion of C3+C4 in the process of paraffinic crude oil storage,in order to ensure safe storage of paraffinic crude oil in oil tank.Though releasing gas proportion of C3+C4 is more than 50%,even 70%,releasing gas volume from per 100 mL crude oil is tiny when naphthenic crude oil and gas are in balance.So in the actual storage,naphthenic crude oil can not be monitored temporarily.2.Designing and setting up ultrasonic cavitation device for study reducing heavy oil viscosity.Study different reaction time,whether ultrasonic cavitation or not,whether methanol/ethanol or not and different volume fractions of cavitation reagent on effect of reducing heavy oil viscosity.Experimental results show that alcohol reagents are good for ultrasonic cavitation,especially,effect of adding ethanol reagent is better than adding methanol reagent.Effect of reducing heavy oil viscosity is best under 3h,150 ?,5% ethanol reagent.Determining distillation range of oil sample(3h,5% ethanol,150 ?)and Da Qing vacuum residuum,though the temperature difference is tiny,it was obvious that temperatures of both appear reversal phenomenon,which indicates that ultrasonic cavitation exert chemical action.however,intensity of the ultrasonic cavitation need to be further improved.3.Simulate different venturi cavitation structure and determine the optimal venturi structure by Fluent software.Designing and setting up hydraulic cavitation device for study reducing heavy oil viscosity preliminarily.Experimental results show that hornsventuri without throat has the most widespread of gas holdup in tube,strength and distance of gas holdup near wall are both the biggest and longest,which indicates that it is the optimal venturi cavitation structure.Adding methanol regent into cavitation process and determining sample viscosity after 1h,3h,5h,results show that viscosity fell by 3.0%,6.5% and 6.5% respectively,which indicates that applying horns venturi without throat into reducing heavy oil viscosity is feasible.Determining distillation range of oil sample and Venezuelan crude oil,it was obvious that temperatures appear reversal phenomenon,even the temperature difference is huge,which indicates that hydraulic cavitation exert strong chemical action.